Case Study Of Retinitis Pigmentosa

Case Study Of Retinitis Pigmentosa
Objective :
To provide education, awareness, medical information and medical knowledge on low vision assessment
in Retinitis Pigmentosa.
Introduction : Retinitis Pigmentosa is a group of inherited diseases that damage the light–sensitive rods
and cones located in the retina, the back part of our eyes. Rods, which provide side and night vision are
affected more than the cones that provide color and clear central vision. The prevalence of Retinitis
Pigmentosa worldwide is approximately one in 4000. Up to one–quarter of all patients with Retinitis
Pigmentosa will become legally blind in both eyes, it is rare to lose all vision. More than half of all
patients with Retinitis Pigmentosa have visual acuity of 20/40 or better in at least one eye. ... Show more
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Visual Field Assessment to assess the patient's peripheral vision. Central and peripheral visual field
defects can be detected by performing confrontation visual field test and amsler or threshold amsler grid
assessment. Supplemental testing such as contrast sensitivity testing, glare testing, Visual Evoked
Potential (VEP), Electroretinogram (ERG), Electrooculogram (EOG) and color vision testing is done for
Retinitis Pigmentosa patient. Low Vision exams involve more test than standard examination, hence its
more time–consuming. Based on the low vision examination, low vision specialist will make suggestion
for optical aids or techniques for adjusting to daily life
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Accommodations Project
The disability group that I would like to focus on for my Accommodations Project is blindness and low
vision. According to the textbook, "the statutory definition of blindness is based on visual acuity and
field of vision. Visual acuity is the ability to clearly distinguish forms or discriminate details at a
specified distance" (Heward 345). For example, Mary is able to see the words on the projection screen
from her desk and she can see it clearly. Having 20/20 vision does not mean that a person has perfect
vision it simply means that they can see at a distance of 20 feet. The American Foundation for the Blind
defines being legally blind as having vision "no better than 20/200 corrected vision in the better eye, or a
visual field not extending beyond 20 degrees in the better eye, or a visual efficiency of no more than 20
percent. The "legal" refers to a ... Show more content on Helpwriting.net ...
There are many instructional strategies that are effective in teaching students who are blind or that have
low vision. One example of an instructional strategy would be seating the student in the front of the
classroom so that they can hear the teacher's instructions clearly (Allan). A student that is blind is unable
to see written instructions that are on a chalkboard so the teacher will have to read the instructions aloud.
Another example "would be to avoid leaving doors and drawers ajar or chairs out from under tables and
desks" (Allan). If there are items in the walkway of a student that is blind they could potentially fall and
get hurt which is why it is also important for the teacher to keep from rearranging the classroom. If the
teacher rearranges the classroom they should inform the student that they have done so. The two
examples that I provided are effective because they help the student be successful in the classroom
despite their

Visual Acuity Lab Report
Results
Demographics
Were included 82 eyes of 49 patients, 32 (69%) females and 17 (31%) males. The mean patient age was
33 +/– 7.4 years (range: 21 to 48 years). Mean follow up was 4.8 years (range 9 to 1 year). The mean
anterior chamber depth was 3.2mm (range 2.8 to 3.67mm). Were implanted 42 Artisan IOL and 40
Artiflex IOL with a mean power of –11.1D
Visual Acuity
Mean preoperative UCVA was 1.9 logMAR and post operative UCVA was 0.3 logMAR after phakic IOL
implantation, showing a statistical significance (p=0.000).
After the surgery we observed that 79 eyes gain 4 or more lines of vision, 20/40 or better was achieved
in 76 eyes (92.68%) after the follow up period.
Mean preoperative CDVA was 0.2+/–0.3 logMAR and after post operative follow up period was 0.01+/–
0.1 logMAR, which was statistically ... Show more content on Helpwriting.net ...
Postoperative central endothelial cell count after the follow up period was 2323+/–286.03 cells/mm2,
which was observed a statistically significative decrease in the cells count. The mean ECD yearly lost
was 121.36 +/–111.04 cells/mm2/year.
IOL distance from Endothelium
Mean distance from the center of the pIOL to the endothelium was 2.2 +/– 0.3mm and the mean distance
from the edge of the pIOL was 1.4 +/–0.2mm both distances were lowly correlated to the endothelium
cells loss (r–0.00 p0.000 and r –.308 p0.05 respectively)
Intraoperative Problems and Adverse Events
There were no intraoperative or postoperative problems. However in one patient elevated intraocular
pressure (IOP) were detected at the postoperative control. Were considered steroid induced, the IOP
returned to baseline levels after cessation of steroid. Throughout all follow–up years, a total of 5 eyes of
5 patients have been received a new intervention due to a tilt of the lens or had been dislocated from the
iris. In this patients the endothelial cells loss was much higher than the

Pseudo Myopi The Refractive Anomaly Of The Eye
INTRODUCTION
Myopia is the refractive anomaly of the eye in which close objects appears clearly, while objects far
away appear blurry. With myopia, light comes to focus in front of the retina instead of on the retina
Myopia is the major refractive error having a worldwide prevalence of 1.5 billion. Children with Myopia
feel difficulties in viewing blackboard in school; they avoid outdoor activities and get isolated from the
peer groups. Untreated myopia may lead to Macular degeneration, Glaucoma, Cataract, Retinal
detachment.
Myopia occurs if the eyeball is too long or the cornea (the clear front cover of the eye) is too curved. As
a result, the light entering the eye isn't focused correctly, and distant objects look blurred. Even though ...
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Because there is insufficient contrast for an adequate accommodative stimulus, the eye assumes the
intermediate dark focus accommodative position rather than focusing for infinity.
3. Pseudo myopia
Pseudo myopia is the result of an increase in ocular refractive power due to overstimulation of the eye's
accommodative mechanism or ciliary spasm. The condition is so named because the patient only appears
to have myopia due to an inappropriate accommodative response.
4. Degenerative Myopia
A high degree of myopia associated with degenerative changes in the posterior segment of the eye is
known as degenerative or pathological myopia. The degenerative changes can result in abnormal visual
function, such as a decrease in best corrected visual acuity or changes in visual fields. Sequelae such as
retinal detachment and glaucoma are relatively common.
5. Induced Myopia
Induced or acquired myopia is the result of exposure to various pharmaceutical agents, variation in blood
sugar levels, nuclear sclerosis of the crystalline lens, or other anomalous conditions. This myopia is
often temporary and

Assignment 1: Explain The Concept Of Exam Lane
Goal: Explain the concept of "exam lanes" and rank on Google for the key phrase
Total words in this document:
Title: Excellent Exam Lanes: What You Need to Know
Exam Lanes 101: A Crash Course
More than just an exam room, an exam lane is the comprehensive site where patients have their vision
checked and ophthalmic professionals spend eight to ten hours of their day conducting exams and
meeting with patients.
Exam lanes include a number of pieces and tools to diagnose various conditions, prescribe corrective
lenses for patients, and give detailed, descriptive reports that improve the ease of diagnosis while
reducing the margin of error. These pieces range from the seat where patients sit for the exam to the slit
lamp, visual acuity system, and more in–depth pieces designed to measure and test parts of the eye.
In the past, exam rooms were the ... Show more content on Helpwriting.net ...
Creating an efficient exam lane, first and foremost, is vital to providing professionals with a workstation
that is conducive to good health for the professional as well as the patient. Rather than hunching over a
slit lamp, stretching to reach an ophthalmoscope or visual acuity tool, or contorting your body to fit the
demands of using a manual refractor, newer exam lanes include automated equipment that alleviates
pain. The exam chair and slit lamp are set to an optimal height that helps to reduce the risk of severe
discomfort and later physical conditions.
Compact: An efficient exam lane will have space for each necessary component. By purchasing a
package, the exam lane has been designed to provide a space for each tool. Not only will this increase
the ergonomic benefits, but will also save time during each appointment. Rather that searching for tools
when they are needed, the exam lane will allow professionals to find what they need, when the item is

Amblyopia Essay examples
Amblyopia
This paper provides a brief description of amblyopia and discusses current research regarding the motion
pathway in individuals with amblyopia.
Amblyopia is a condition in which visual acuity in one eye is greatly reduced. It is caused by lack of
stimulation or disuse during visual development (Rose, 1998). Because the eye is not fully developed at
birth (Jarvis, 1992, as cited in Rose, 1998), infants need stimulation to complete the visual neural
pathway. When one or both eyes are inhibited, for example due to misalignment of one eye (strabismus)
or a large difference in refractive power between two eyes (anisometropia), the neural pathway for the
inhibited eye develops abnormally, or does not develop at all. At ... Show more content on
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This information is important because it could provide meaningful insight into the nature of the
underlying problems involved (Hess & Anderson, 1993).
There is a general consensus that amblyopes have reduced contrast sensitivity, grating acuity, and spatial
resolution in one eye and a loss of binocular vision (Levi, 1991; Sireteanu et al., 1977, as cited in Fahle
& Bachmann, 1996). Amblyopes also suffer from "crowding" (Levi & Klein, 1985, as cited in Fahle &
Bachmann, 1996) which causes difficulty, for example, in comprehending a letter found in text rather
than an isolated letter. The mechanisms delegating positional information are also disabled in amblyopes
(Rentschler & Hilz, 1985, as cited in Fahle & Bachmann, 1996).
Even though amblyopia results in a profusion of visual obstacles, there is one area for which amblyopia
may actually provide beneficial. Arguments have been made that while fine spatial detail has been
affected in amblyopes, the motion pathway has not been affected (Chung & Levi, 1997; Kubova, Kuba,
Juran, & Blakemore, 1996), and may even be more acute (Fahle & Bachmann, 1996). It has been
proposed that in amblyopes the parvocellular pathway is impaired resulting in loss of fine spatial detail
(Kubova, et al., 1996). On the other hand, parasol cells that lie in the magnocellular layers

How Vision Loss Affects Psychosocial Well Being Among The...
Abstract Purpose: to examine how vision loss affects psychosocial well being among the people in the
middle and upper class and how the cope with their visual impairment
The purpose of this study is to understand and discover the psychosocial state and well–being for
individuals with vision loss among the upper and middle class. At this stage in the research, the
participants chosen will be asked about their mental state and vision loss, which will be generally
observed through interview questions on PTSD, depression and motivation. Previous studies have stated
that overall poorer mental well–being and quality of life was found in visually impaired people in
comparison to fully sighted people (Stevelink & Fear 2016).
Method: Qualitative study, interview research questions
Keywords: Visual Impairment, Vision loss, Psychosocial well–being, PTSD, depression, motivation
_____________________________________________________________________________________
Introduction
Visual impairment is a state wherein an individual experiences difficulty in seeing or not being able to
see anything physical presented to them. According to Mandal, MD (2013) It is a state where a visually
impaired person's eyesight cannot be corrected back to a "normal level". Visual impairment is often
associated with old age. In Europe, an estimated 15.5 million people have visual impairment and in
seven countries in Europe, about 50% of blindness is caused by age–related macular degeneration.
(Dibb,

Amblyopia Research Paper
AAO
Amblyopia is a unilateral Of, less commonly, bilateral reduction of best–corrected visual acuity that
cannot be attributed directly to the effect of any structural abnormality of the eye or the posterior visual
pathways. Amblyopia is caused by abnormal visual experience early in life resulting from one of the
following: strabismus anisometropia or high bilateral refractive errors (isometropia), stimulus
deprivation
Amblyopia is responsible for more unilaterally reduced vision of childhood onset than all other causes
combined, with a prevalence of 2%– 4% in the North American population. This fact is particularly
distressing because, in principle, most amblyopic vision loss is preventable or reversible with timely
detection and appropriate ... Show more content on Helpwriting.net ...
Force use of the poorer eye by limiting use of the better eye.
Cataract Removal
Cataracts capable of producing amblyopia require surgery without unnecessary delay. In young children,
amblyopia may develop as quickly as 1 week per age of life. Removal of Visually Significant congenital
lens opacities during the first 4–6 weeks of life is necessary for optimal recovery of vision. In symmetric
bilateral cases, the interval between operations on the first and second eyes should be no more than 1– 2
weeks. Acutely developing severe traumatic cataracts in children younger than 6 years should be
removed within a few weeks of injury, if possible.
Refractive Correction
In general, optical prescription for amblyopic eyes should be based on the refractive error as determined
with cycloplegia. Because an amblyopic eye's ability to control accommodation tends to be impaired,
this eye cannot be relied on to compensate for uncorrected hyperopia as would a normal child's eye.
Refractive correction for aphakia following cataract surgery in childhood must be provided promptly to
avoid compounding the visual deprivation effect of the lens opacity with that of a severe optical deficit.
Both anisometropic and ametropic amblyopia may improve or resolve with refractive correction alone
over several

Period Of Susceptibility In Kittens
1. The period of susceptibility, as defined in the present study, is a critical period in which vision is
developed. The researchers discovered that the period of susceptibility in kittens has a sudden onset at
the beginning of the fourth week of life. A gradual decline in the period of susceptibility is seen
sometime between the sixth and eighth weeks of life and continues through the end of the third month of
life. By the end of the third month and the beginning of the fourth month, the period of susceptibility
disappears.
2. Figure 2 consists of two histograms (Figure 2A and Figure 2B) depicting the ocular dominance
distribution of cells in the left visual cortex of two kittens born of the same litter. In this part of the study,
the ... Show more content on Helpwriting.net ...
Figure 9 contains two ocular dominance histograms of the left visual cortexes (9A and 9B) in which two
kittens had a period of monocular deprivation in their right eyes during the first three to four months of
their lives. In Figure 9A, both eyes were kept open for thirty months and then the results were recorded,
which shows ocular dominance in the left eye (expected based on the research). However, in Figure 9B,
following the original period of deprivation in the right eye, the kitten's left eye was then sutured closed
for a complete year, after which remained open with the right eye for four years and ten months. The
results of this cat were recorded at age six years and one month. One may expect the results in Figure 9B
to show ocular dominance in the right eye due to the fact that the left eye was closed for a longer period
of time (roughly 8 months). However, the results instead show ocular dominance in the left eye like
Figure 9A does. This can be explained based off of the research that the period of susceptibility ends
around the fourth month of life. Because the right eye was deprived during the period of susceptibility,
but the left eye deprivation occurred after the conclusion of this sensitive period of cell growth and
connection formation, the left eye displayed dominance. This again suggests that the length of
deprivation does not necessarily matter as long as it does not occur during the period of

Cataract: Currable Blindness In The World
Cataract is the most common cause of curable blind¬ness in the world. It remains the leading cause of
blindness in India (62.60%) (Vijaya L et al 2005 ). High quality, high volume cataract surgery is needed
in community eye care centres to effectively manage the large back–log of cataract blindness (Natchiar
G et al 1994 ). The number of cataract extraction procedures performed all over the world is predicted to
increase under the auspices of Vision 2020 Global Initiative about 35 millions by 2020 (Taylor, 1999 ).
Couching is the first surgical procedure known to treat cataract surgically and is only of historic interest.
Intracapsular cataract extraction (ICCE) is now obsolete. Cataract extraction with intraocular lens
implantation is widely

Clinical Procedures For Ocular Evaluation
Clinical optometrists take on the task of routinely evaluating and dealing with patients on a daily basis
while also attempting to maintain a healthy, successful business environment. The book Clinical
Procedures for Ocular Evaluation describes how clinical optometrists maintain healthy relationships
with patients and also detail different tests that are commonly implemented. These tests allow for
doctors to determine a patient's well–being and follow the necessary steps to improve the state of their
eyes. Clinical Procedures for Ocular Examination is a viable tool that can be used to manage a patient's
complaints and general health history, and assess which phases of examination and problem–specific
testing should be implemented. There ... Show more content on Helpwriting.net ...
Since its creation in 1888, this company has been dedicated to "accelerate learning through intuitive,
engaging, efficient and effective experiences – grounded in research" (mheducation.com). Once again,
because of the esteem and reverence of its publisher, Clinical Procedures for Ocular Examination has
had its content and reliability reinforced. This book consists of several chapters that help outline the best
ways to maintain a functional and healthy work environment. The first chapter does by explaining the
best ways to treat and communicate with your patients. It emphasizes the importance of communication
and making sure the patient feels welcome, is well–informed about whatever issues they may have, and
has their questions fully and accurately answered (Kurtz 3) . The main points in this chapter are as
follows: relating effectively and sensitively to patients, conveying compassion and empathy, perceiving
verbal and non–verbal communication from patients, eliciting information from patients and observing
changes in mood and activity, communicating quickly, effectively and efficiently, reading and legibly
recording observations and test results, and completing assignments, patient records, and correspondence
accurately (Kurtz 2–23). Another important component this chapter covers is how to analyze a patient's
case history and assimilate it with their symptoms. A case history is a record of a

What Is A Cataract?
A cataract is a condition in which the transparent lens becomes progressively opaque due to varying
circumstances such as genetics, environment, and diet, amongst many other variables. Regardless of the
pathogenesis from which the cataract developed, a reduction in visual performance and thus, visual
acuity is exhibited. In order for the visual acuities to be enhanced again, the cataract needs to be
removed. An ophthalmologist will remove it and replace the natural lens with an intraocular lens (IOL).
Cataract surgery has shown to be one of the safest and most effective type of surgery in which patients
report having better vision in a matter of a few days. Briefly, cataracts are cloudy areas that form in the
lens that make it difficult ... Show more content on Helpwriting.net ...
Retinal illuminance is a key factor in the sharpness of someone's vision and in turn, their visual acuities.
If not enough light is reaching the retina, the human brain cannot distinguish between certain details in a
word, much less a letter. The cataract, depending on where it is located in the lens, causes light to bend
around it in an effort to reach the retina with full illuminance. This allows the light to reach the
photoreceptors of the retina, which can then be transduced into a chemical signal that follows its
pathway to eventually, the visual cortex. This results in an image perceived by the brain. However, if the
cataract is big enough, it can prevent the light from reaching the photoreceptors and disrupting the whole
process of the visual system. Therefore, it is imperative that the lens be free of noise in an effort to
transduce as much light as possible to the retina. This means removing the cataract, thereby increasing a
person's visual acuity.
In conclusion, cataracts not only affect visual acuity and contrast sensitivity, it affects the quality of life
for those that have the condition. It is important to detect, monitor, and treat cataracts if it becomes an
issue in performing everyday tasks such as reading, driving, and detailed work at near. By completely
removing cataracts or replacing the lens, patients are better able to improve their visual acuities and
perform such tasks. Removing cataracts at an earlier age can also have long lasting effects on visual
performance and quality of life in their

Safely Inserting Contact Lens
Safely Inserting and Removing a Contact
Inserting a contact lens. A skill I never thought I would need until the day arrived for an annual doctor's
appointment and my doctor told me I should go see an ophthalmologist (an eye doctor). Needless to say,
after a visit with the burly eye doctor, I had gotten glasses and was still refusing to get contacts. I knew I
probably needed them, but the thought of sticking my finger in my eye to but in a rubbery circular thing
gave me the chills. It just wasn't natural. And I went a long time with just my black rimmed glasses, that
is, until soccer season came around. I was fine. I could see... couldn't I? That was what I asked myself
after been hit in the face with the ball during my team's first game. Was ... Show more content on
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Took you long enough. But now, what about safety? You're probably saying "Safety? I'm not riding a
bike." It might be a lot smaller than a bicycle, but it's no less dangerous. An unsanitary contact can cause
bacteria to grow in your eye resulting in certain funguses to grow which can ultimately cause blindness.
Even going to the beach with contacts can be bad. Sand particles can get under your contact and scratch
at your eye without you even noticing until it's too late and your eye is damaged, sometimes beyond
repair. Even sleeping in your cantact are a big no

Cortical Visual Impairment
HISTORY: For early diagnosis of disorders presenting marked cortical visual impairment, VEPs were
considered crucial diagnostic test since advent of EEG and multiple variants to this protocol have come
into existence as described below.
a. FLASH VISUAL EVOKED POTENTIAL:
Adrian et al (1934) proved that the regular repeating flash stimulus could induce the electric response
from the visual cortex. E. Herba et al (2006) employed FVEPs to show that the maternal zinc
supplementation may have a beneficial influence on visual cortical responses in newborn rats. FVEPs
have been regarded as the consequence of increased excitability of cortical circuitry to flash stimulation
(FVEP) (Aguglia et al., 1991; deSeze et al., 1998; Finsterer et al., 1999; ... Show more content on
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Low–speed blinking light (i.e., blinking frequency of less than 3.5 Hz) generates transient VEPs and
characterized with a negative peak of around 75ms and a positive peak of around 100ms. According to
waveform patterns VEPs, categorization seems appropriate as transient VEPs and SSVEPs. The function
of pattern size quantifies visual acuity through electrophysiological parameters of amplitude and
latency26–31. The amplitude and latency of the VEP have been studied in adults, children, 32–33 and
term infants 34. In the preterm infants, it shows developmental kinetics of the VEP response and the age
of its stabilization34, 35–37.The lack of clinical relevance of the VEP in infants in whom ROP stages 4b
and 5 developed also has been established38–40. While transient VEPs occur in reaction to visual
stimuli which blink at a frequency of less than 3.5 Hz, SSVEPs occur in reaction to stimuli of higher
blinking

A Brief Look at Antiangiogenic Therapy
Although laser photocoagulation and PDT destroy pathological vessels, they neither extenuate the
primary angiogenic stimuli nor prevent the development of new vessel. Antiangiogenic substances are
able to resolve these problems. Antiangiogenic therapy prevents recurrence of AMD by reversing the
CNV lesions. Pegaptanib (brand name: Macugen) was the first intravitreal pharmacotherapy approved
by the FDA in 2004. It binds to VEGF165 and is responsible for "blood–retinal barrier breakdown and
pathological intraocular neovascularisation", subsequently inhibiting pathological leakage and
angiogenesis. According to the results of the
VEGF Inhibition Study in Ocular Neovascularisation (VISION) trial, pegaptanib is proven to be an
effective therapy for wet AMD. However, reinjections have to be done regularly as the molecule of
pegaptanib is degraded enzymatically by intraocular nucleases. Endophtalmitis, traumatic lens injury
and retinal detachment were also observed in the patients receiving this treatment.
In 2006, FDA approved the usage of ranibizumab (brand name: Lucentis), a humanized monoclonal
antibody fragment that has a high affinity for VEGF, as a therapeutic option for wet AMD. Ranibizumab
is different from pegaptanib as it is not restricted only to binding VEGF165 isoform but binds to all
human VEGF isoform. It reduces leakage in vessels as well as decreases retinal and choroidal
neovascularisation in animal models. The findings of MARINA study demonstrated that

Reflection Paper
Growing up, my vision appeared to get worse and worse every year. Until I was in first grade I never
thought to told my mom, considering it never caused any problems. It was until I would find myself
squinting at the board everyday did my teacher wonder if something was wrong. Shortly after, I found
out I needed glasses. From first grade to tenth grade, I went through multiple pairs of glasses, and my
vision continued to deplete. I never complained about having glasses because they rarely got in my way.
That was until high school, when I started running. Trying to sprint with glasses on can be extremely
challenging. It took me two years to finally get the courage to get contacts. As someone who struggled
with getting contacts in everyday over the summer and struggles now, I want to help those who go
through the same conflict. Waking up in the morning you are presented with two choices, either take out
the contacts that you had in last night, or you wake up blind, and have to groggily feel your way to the
bathroom. As you reach around for your contacts, you must not forget to knock over various of your
toiletries in the process. Disregarding everything strewn out on the floor, open your contact packages.
Not even caring that you just spilled saline over your shirt, sink, and hands, try helplessly to grab one
contact out of the package. Personally, since I have two different prescriptions for each eye, I start with
my right eye. Now you begin. Set aside five minutes of this

Endophthalmitis Vitrectomy Studies
Postoperative endopthalmitis is one of the most devastating complications of cataract surgery. Despite of
the great progress in the lines of treatment of this serious condition, the visual results are still poor and
about 40% of cases sustain severe visual loss (corrected distance visual acuity of less than 20/200).[1]
The incidence of endophthalmitis after cataract surgery varies according to the surgical technique, it has
ranged from 0.04% to 0.13%.[2–3] This complication can end by evisceration as a last stage in
management.[4]
Endophthalmitis Vitrectomy Study (EVS) results demonstrate that only patients in a subgroup of initial
light perception–only vision or worse derive a benefit from immediate pars plana vitrectomy (PPV).[5]
Immediate ... Show more content on Helpwriting.net ...
Quantitative data was represented as mean, standard deviation, median and range. Data was analyzed
using student t–test to compare means of two groups and paired t–test compared pre and post results.
Qualitative data was presented as number and percentage and compared using either Chi square test or
fisher exact test. Graphs were produced by using Excel or STATA program. P value was considered
significant if it was less than 0.05.
Results
Baseline and postoperative data obtained for both groups are summarized in table I and II. The mean +
standard deviation (SD) of age was 56.95 ± 15.75 and 53.69 ± 12.33 in group 1 and 2 respectively.
Visual Acuity
Snellen visual acuities were converted to a Logarithm of minimum angle of resolution (LogMAR) score
for data analysis. This was performed by taking log10 of the reciprocal of Snellen fraction. Grover et al,
estimated a decimal VA of 0.0025 for counting fingers (CF), 0.002 for hand motion (HM), 0.0016 for
light perception (LP), and 0.0013 for no light perception (NLP).[12] By converting these values to
logMAR score, we considered CF equal to 2.6, HM equal to 2.7, LP equal to 2.8 and No PL equal to

Visual Response Essay
In 2001, Morland et al. (2001) investigate the impact of visual dysfunction on cortical visual responses
with three different studies. This studies differ in the sense that the subjects have visual deficits that are
expressed at different levels of the visual system. First, they describe the effects on the cortical visual
maps of abnormal retinal receptor distributions that are found in rod monochromacy (only possesses
operating rod photoreceptors). Subject KN, aged 56 year old has a complete absence of cone
photoreceptors. KN also has a central scotoma which has been estimated to be between 10 min and 1º,
but estimates are error prone due to nystagmus. The results show that the cortex undergoes a remapping
whereby the regions that would normally ... Show more content on Helpwriting.net ...
Second, they evaluate how the information from each hemifield is represented in the human albino
areas. In human albinism the principle deficits occurs at the optic chiasm, where fibres undergo almost
complete crossing unlike the normal pattern in which approximately half of the fibres project
contralateral to the eye. In order to address the aim, they presented stimuli to the right and left hemifields
of an albino viewing monoculaly. Subject, aged 55 year old, tyrosinase positive, female albino, who had
best corrected acuity of 0.33 and nystagmus no greater than 3º in amplitude. They found abnormal visual
cortical activity in a human albino. Monocular stimulation of each hemifield resulted in activations in
the hemisphere contralateral to the stimulated eye. This is consistent with abnormal decussation at the
optic chiasm in albinism. They believed that the reorganization is a likely consequence of developmental
and not genetic factors as found in the Boston pattern (Guillery, 1986). Finally, they described how
visual field defects can be documented with retinotopic mapping techniques in the case of cortical

Visual Impairment Paper
As a person with a major visual impairment myself, I found the first video fascinating. In the video the
audience is introduced to Mason, a 6–year–old boy, whom is completely blind in one eye and has only
partial vision in the other. His overall visual acuity is approximately 20/300 versus the standard visual
acuity of 20/20. In the video the types of technology introduced and discussed were the Mountbatten
Brailler, iPad, and a Smart Board. A Mountbatten Brailler is a type of Braille machine, which in a
traditional braille machine that has been equipped with audio as well as word processing capabilities. It's
particularly useful for children because of the audio responses. Mason also utilized an iPad at home and
in school as an additional education tool because of the capabilities to run education games and increase
the size of text and images to make it ... Show more content on Helpwriting.net ...
Cerebral Palsy is a permanent and debilitating condition that causes not only a physical impairment and
disability but in cases like Elle can cause communication disabilities or even cognitive defects. Elle is
unable to speak so her main piece of assistive technology is a Dynavox, which is a speech–generating
device that is operated by a head mouse that allows Elle to communicate and express herself. Prior to
acquiring the Dynavox her family had been through multiple devices and assistive technology items.
They used a traditional book chart. Which consists of a book broken into categories of basic needs and
communication symbols and the user shifts their eyes from one category to another in order to
communicate. They used a device called a Pathfinder, which is also an assistive communication device
that looks like a large board with multiple buttons. They eventually began utilizing a laptop with
communication software and eventually the school helped her find the Dynavox, which gave her better
communication

Biological Processing System : Understanding Color And...
Biological Processing System: Understanding Color and Contrast
Introduction
While interacting with the world, human visual system is perhaps the first and foremost biological
process system that directly involves in detecting information. As Colin Ware (2013) noted in
Information Visualization, "We acquire more information through vision than through all of the other
senses combined". Hence, it is crucial for information designers to understand influential factors which
affect our visual system in order to optimize information visualization for users. With visual sensory
system acting as a signal detecting system, this paper intends to look at a variety of perceptual elements
of a particular case but mainly focuses on their visibility in terms of contrast and color. More
specifically, the paper will be examining these concepts as if the website is viewing by an elderly user.
The Case
The Town of Natick website (http://www.natickma.gov) is an online portal which contains information
primarily for town residents, business owners, and potential visitors. The website not only serves as a
portal for information presenting, but also serves to accommodate certain actions, such as applying for
jobs, paying bills online, downloading business related forms. That being said, the website comprises of
two primary goals: 1) to present information; 2) to provide actionable directions to help complete certain
tasks. The goal of this paper is to construct a case where the Natick website

PREVALENCE OF NON STRABISMIC VERGENCE DYSFUNCTIONS
IN AN...
PREVALENCE OF NON STRABISMIC VERGENCE DYSFUNCTIONS IN AN ORTHOPTIC CLNIC
INTRODUCTION
In the preceding generations, fine distance visual acuity and stereoscopic vision were of paramount
importance, since the survival depended absolutely on the capability to farm, hunt and fish. But today,
the emphasis has shifted virtually from distance visual functions to two dimensional near visual tasks
such as desk work, reading, computer usage etc.The presence of non strabismic binocular dysfunctions
such as accommodative and vergence anomalies make it difficult for the visual system to perform these
kind of activities with accuracy and effortlessness. When persons, who are in short of suitable
accommodative and vergence amplitudes, are involved ... Show more content on Helpwriting.net ...
In a clinical study to determine the presence and clinical implications of the general binocular
dysfunctions in a population of university students, Esteban Porcar et al 4 found a prevalence of 32.3 %
of non strabismic binocular anomalies.
To achieve as estimate of the population prevalence of vergence dysfunctions, we have systematically
reviewed the previous studies related to this. So this study was designed to estimate the prevalence of
vergence dysfunctions in an orthoptic clinic set up and also to set up well defined diagnostic criteria for
all the vergence anomalies.
MATERIALS AND METHODS
755 Patients above the age of seven years presented consecutively to the orthoptics clinic of Sankara
Nethralaya, Chennai between March 2010 and February 2011 was considered for this retrospective
cohort study based on the inclusion and the exclusion criteria with the help of Medical Record
Department and Electronic Medical Record (EMR) search engine.
The inclusion criteria used were age more than or equal to seven years, distance best corrected visual
acuity of > 6/9 in both the eyes, near best corrected visual acuity of N6 @ 30–40 cm, adequate sensory
fusion with worth four dot test for distance as well as for near, Random Dot stereo acuity of 500 arc
seconds or more. All the patients who had a history of monocular or binocular amblyopia, manifest

Stereopsis Impairment
Stereopsis is an impairment that prevents those who have it from seeing clearly. Stereopsis vision can be
described as viewing an image during the presence of aberrations. The apparatus is a tool that can give
the viewer the ability to see one clear image when confronted with images that are shown to be of
slightly different angles. The author of this article believed that if the apparatus can be operated to
converge two images then more information may be obtained relating to the association of binocular
vision and stereopsis impairment. By obtaining this information it is possible that Stereopsis Impairment
can be cured for those who have it. It is important to be able to cure the impairment that has been
affecting lives for years.
To complete this experiment a variety of materials were used. A liquid–crystal–on–silicon spatial light
modulator, LCoS–SLM, was used as the phase manipulating device. This modulator contains a liquid
crystal layer which was put between a transparent electrode and a silicon wafer with an array of 800 x
600 pixels.A wavelength of ... Show more content on Helpwriting.net ...
The Dependent Variable is the change in Stereo–acuity of the subjects between the two machines under
the influence of binocular aberration combinations and normal viewing conditions. The basic
components of the BAOVS remained constant. For example, the light– crystal–on–silicon spatial light
modulator. The control group used a Binocular Adaptive Optics Visual Simulator ( BAOVS) to test the
stereo–acuity of their subjects. The experimental group used a modified version of the BAOVS, which is
more compact, does not include a wavefront sensor, does not include a Badal optometer, and the stimuli
are presented within a pair of internal

Visual Acuity Research Paper
What is visual acuity?
Visual acuity is commonly referred to as the clarity of vision and is dependent on both optical and neural
factors, such as the sharpness of the retinal focus in the eye, the health of the retina, and the sensitivity of
the brain. One aspect of visual acuity is the ability of recognizing and discriminating the colours of the
visible spectrum of light. There are two types of cells involved in vision: rod cells and cone cells. Rod
cells are highly sensitive cells that allow for low–acuity vision in dim lit environments, however they
lack the detail and colour information. Cone cells are high–acuity cells that provide colour information
in well–lit environments. Rod cells provide more convergence than the cone cells which results in their
increased sensitivity but also results in the decreased acuity.
Physiology behind differences in visual acuity in men vs women
It is generally believed that woman have higher discriminatory abilities with respect to naming of
colours, which often implies they have superior colour vision. It has been found in many studies that
women perform better than men in the matching of colours from memory, and tend to use a plethora of
different words to describe sets of colour stimuli. It is possible that there exists an underlying
physiological explanation for why there should be ... Show more content on Helpwriting.net ...
This means that the separation of the colours (particularly red) will be affected depending on whether the
serine or alanine pigment variants are expressed. It has been found that these variants can actually result
in measured differences in spectral separation (Rodriguez–Carmona et al, 2008). In males which have a
single X–chromosome approximately half will have the alanine L cone pigment and the other have will
have the serine L cone pigment (Murray et al,

Optician Research Paper
Optician Katy: Helping in enhancing eye care services
Opticians can be described as well trained eye care experts who have to go through extensive training to
practise opticianry. In simple words they are basically those people who dispense and design eye glasses,
low vision devices, contact lenses and other ocular instruments. Professionals have to qualify for a
specific criterion which will certify that they are skilled enough to practise like an optician. They mostly
work in places like hospitals, laboratories, retail stores and eye care clinics. In USA a certified optician is
educated in optical Science and he or she is entitled by the name Ophthalmic Optician.
In recent time the demand for an optician has increased drastically. The main ... Show more content on
Helpwriting.net ...
It also gives a confirmation that children possess the visual acuity to do other educational activities.
Regular checkups will ensure that you get the correct advice which will help in taking care of your eyes
and make you aware of the current condition of your eyes.
Eyes are very essential part of your life and you should take all the essential steps to maintain it.
Regularly visiting your eye doctor will certify that your eyes are in good condition and will detect any
signs of severe disease.
The role of an optician Katy in an eye hospital In recent times most of the eye care clinics and hospitals
have in house opticians. It is very convenient for the patients as it saves them from the trouble of going
somewhere else. Katy Optician is an essential part of any eye care hospital or clinic. They take care of
the important parts of the outpatient services. The duties of an optician have been expanded since its
introduction in a hospital setting. Their duties are providing frontline services in the tertiary structure of
eye care services. They have become a very prominent part of eye care services and every hospital is
incorporating it in their

New Born Infants And Visual Acuity
New born infants have poor visual acuity as opposed to adults. Visual acuity measures to what extent an
individual can detect visual detail. Their lack of visual acuity means they see the world a more ill–
defined manner. Adult visual acuity is thirty times the visual acuity of a new born (Van Hof–van Duin &
Mohn 1985). Atkinson & Bradrick (1981), supported this and found that new born infants could only
detect the separation of lines if they are 30 times wider than the minimum width adults can detect. There
is at least a five–fold improvement by 6 months of age in acuity, though it takes several years for it to
reach adult level, Brown & Yamamoto 1986. New born infants also have poor visual accommodation,
needed to make sharp retinal images at different distances. Although infant perception differs in terms of
acuity, infant perception on size and shape constancy requires less development. Adults understand that
objects have a constant shape and size, regardless of their distance, and the angle of perception. The
developmental question lies on whether size and shape principles guide infant perception, or whether
constancies are developed through experience. This argument is one of many in exploring whether
infants learn through cognitive adaptations, or whether they learn through experience and what the
environment offers them. Previous assumptions by Piaget, state that these principles were not present at
birth, but developed towards the end of the first year. This

The, The Silent Thief, By. Levi, Knill And Bavelier
Draft essay
Amblyopia is described by; Levi, Knill and Bavelier (2015) as a neurodevelopmental disorder of the
visual cortex. A disorder characterised by Rose (1998) as the "silent thief", a term that purportedly
portrays the consequences of amblyopia going undetected. Amblyopia has been reported as the most
common cause of monocular blindness worldwide Wong (2012), and in a recent review conducted by
(Tailor, Bossi, Greenwood and Dahlmann–Noor, 2016) was cited the most common visual deficit among
children in the UK. Bretas and Soriano (2016) describe amblyopia as the result of visual deprivation due
to impaired binocular function. An impairment thought typical of the two most commonly proposed
underlying causal factors; strabismus and ... Show more content on Helpwriting.net ...
Importantly, findings demonstrate the potential plasticity of the adult brain beyond the hypothesised
critical period for visual development, Tailor et al., (2016), Nancy (2015). Critically, binocular
treatments are producing encouraging improvements among adult amblyopes Vedamurthy, Nahum,
Bavelier and Levi (2015), Li et al., (2013), posing important implications for clinical practice. The aim
of this essay is to explain amblyopia with reference to 'strabismus and anisometropia'. To discuss
traditional methods and newly developed binocular treatments that aim to address the binocular
dysfunction of the amblyopic brain.
Amblyopia occurs during the first 3 years of life Levi et al (2015) and doesn't develop beyond the age of
8yrs supporting the 'critical period' of susceptibility. However, this doesn't evident a theory for a null
treatment effect among amblyopes beyond this period.
STUDENT NUMBER 119049491
Anisometropia causes blurred vision usually in one eye inhibiting normal visual perception and thus
causing disparate visual input to the cortex Tailor et al., (2016). Clinically anismetropia is described as a
difference in refraction between the two eyes Barrett (2004). Tailor et al., (2016) describes strabismus as
a misalignment of the visual axes also resulting in incongruent visual input to the visual cortex, thus both
anisometropia and strabismus cause binocular dysfunction. The

Cortical Visual Impairment
Some of the issues that plague individuals with cortical visual impairment are losses within central
and/or peripheral vision, inability to perceive depth, sensitivity to light, color or contrast and frustration.
Research by Roman, Baker–Nobles, Dutton, Luiselli, Flener, Jan, Lantzy, Matsuba, Mayer, Newcomb,
& Nielson states that 'CVI should be defined, albeit arbitrarily, by a reduction in visual acuity, in the
visual fields, or in a child's ability to see compared to other children of the same age." (Roman, Baker–
Nobles, Dutton, Luiselli, Flener, Jan, Lantzy, Matsuba, Mayer, Newcomb, & Nielson, 2010) When an
individual has CVI they usually rely more on their peripheral vision than their central vision. Most of the
items we see require some

Cataract Surgery
Definition
A cataract is defined as an opacity of the lens of the eye that causes partial or total blindness. The word
is derived from the Latin "cataracta", which means "waterfall." To the eye of an observer, the foamy
white opacity of an advanced cataract resembles that of the turbulent water of a waterfall. (Chang,
Cataracts Definition, 2014)
Etiology
The lens is a naturally clear, transparent, and avascular structure located behind the iris. Light passes
through the transparent lens to the retina to produce clear, sharp images on the retina. The lens is made
mostly of water and protein fibers. The protein fibers are arranged in a precise manner that makes the
lens clear and transparent. When the lens undergoes changes, and the structure ... Show more content on
Helpwriting.net ...
Studies show that overall 89.7% of post–surgery cataract patients achieved 20/40 visual acuity or better.
To put into perspective, visual acuity of 20/40 is the acuity necessary to obtain an unrestricted driver's
license (Powe, Schein, Gieser, Tielsch, Luthra, Javitt & Steinberg, 1994).
Patients can resume normal activity such as reading, walking, eating, and watching television the
evening of surgery.The eye may be patched, depending upon whether anesthesia was local or topical.
The eye is typically examined on the first post–operative day. Many surgeons allow resumption of
driving at the level immediately prior to surgery at this time, as long as continued patching is not
required. Sutures are removed at 6 to 12 weeks if there is suture–induced astigmatism. (Jacobs, 2015)
Patients typically are seen one day, one week, and one month after surgery to monitor for complications
and proper healing. Patients with large incisions typically are advised not to undertake heavy lifting or
strenuous activity for several weeks to several months. Patients with smaller incisions could resume
regular activity after a period of days to weeks. (Jacobs,

Reduced Visual Acuity Summary
Summary
Reduced visual acuity can be addressed through a range of options, including: familiarizing the student
with their task and environment moving the student closer to the object(s) and vice–versa, increasing
contrast between the object(s) and background, appropriate lighting, and having an organized
environment with contrasting color to highlight areas like stairs and doorways
For students with reduced visual acuity, use of corrective lenses; sunglasses with photogrey lenses; and
turning away from, or repositioning the light source can be effective methods for addressing reduced
visual acuity
Central visual field loss can be addressed through: non–optical magnification; an organized and visually
simplified environment; if there is glare – appropriate illumination to better see color or less; use of non–
optical magnification
For students – central visual ... Show more content on Helpwriting.net ...
Peripheral visual field loss can be addressed by: helping the student acquire more awareness of their
environment, using visual cues to help with organization; utilizing tinted glass or mini–blinds, using
additional and glare–free illumination; and allowing extra time for light/dark adaptation and time to
complete tasks
For students with peripheral visual field loss, use of a long cane can help identify edges of an object
and/or utilizing sun wear or preferential seating to reduce glare and enhance acuity
Cortical (cerebral) visual impairment can be addressed through: having an environment that is visually
simplified and well–organized, with visual cues to denote sections of the room; presenting visual
information to a student slowly, while allowing adequate response time for visual processing and
integration of information using more than one sense, such as smell or touch; using objects that visually
engage the student (such as red or yellow colors, or favorite toys)
For students with cortical visual impairment, use of mnemonics or a mobility device – such as a long
cane can be

Diagnosis And Treatment Of Nursing Essay
A consecutive series of patients who had undergone anatomically successful MH closure and were
followed for at least 6 months postoperatively were enrolled in this study. All patients were diagnosed
with a stage 2, 3, or 4 idiopathic MH according to the Gass classification system(17) and underwent a
comprehensive ophthalmologic examination before and 1, 3, and 6 months postoperatively, including
measurement of the best–corrected VA (BCVA), binocular indirect ophthalmoscopy, and non–contact
lens slit–lamp biomicroscopy. The SD–OCT examination also was performed in all patients on the same
day as the clinical examination. Standard 3–port pars plana vitrectomy for MH repair consisted of a core
vitrectomy with intravitreal injection of triamcinolone acetonide to visualize the vitreous gel, surgical
creation of a posterior vitreous detachment if it had not yet occurred, ILM peeling using Briliant blue G
(BBG), and fluid–gas exchange followed by flushing with a mixed non–expansile concentration of 20%
sulfur hexafluoride. Patients were instructed to remain facedown for 2 to 7 days postoperatively.
Anatomic success was defined as the presence of a flat or closed MH 1 month postoperatively confirmed
by biomicroscopy.(18) All patients provided written informed consent after they received a detailed
explanation of the surgical procedure and SD–OCT follow–up examinations. Our retina specialist (SB)
performed the surgeries. One of two experienced examiners performed the VA

Comparing Visual Systems: Bats Vs. Humans
Leah Meltser PHBM 207.01 Assignment 1: Comparing Visual Systems 2/12/17 Visual Systems: Bats
Versus Humans One has probably heard the simile, "you must be blind as a bat!" Well in fact, this
statement is false, bats are not blind. Formally known in the mammal family as Chiroptera, bats can be
split into two sub orders known as mega–bats (flying foxes or fruit bats) and micro–bats. Typically,
when bats are thought of it is commonly known to have the characteristics of having echolocation, or
sonar vision, to aid detection of objects in complete darkness. As illustrated in Figure 1, echolocation is
the use of sound waves made by the contraction of the larynx, these waves are then reflected back from
the moving object to signal the bat. ... Show more content on Helpwriting.net ...
Both bats and humans have a threshold of approximately 10–7 Apostilbs, which is a measurement of
light density. However, a flying foxes' acuity is maintained much longer as illumination decreases until
roughly 10–4 Apostilbs, which is when acuity begins to fall off as demonstrated by the Figure 3.
Likewise, both humans and flying foxes have similar positioned eyes toward the front of the skull
providing binocular vision. This means that both eyes are being used at the same time in order to create a
greater depth of field. Both visual systems contain a majority of the same structures, but overall, they are
completely different systems due to the fact that we are not nocturnal, nor do we need to be. Although
the visual systems of bats and humans vary in many ways, both visual systems have evolved to benefit
each species differently. While humans see life in color with their cones during the day, bats are the
kings of nocturnal mammals and are capable of maneuvering throughout the night. It has become clear
that bats are capable of so much more then just echolocation from a visual perspective. It is beyond
fascinating to realize that what was once thought of as true, is actually false in reality. Therefore, it is
safe to say that the phrase "you are as blind as a bat," can be put to

A Brief Note On Common Geriatric Diagnosis Topic Essay
Student Name: Andrew Thorne
Common Geriatric Diagnosis Topic: Cataracts –Impaired sensory perception
Appropriate Activity Describe Activity What are benefits of this activity for these patients? What patient
education should you provide to the patient about this activity? What are contraindications for patients
related to this activity?
Visual acuity exam Snellen eye chart exam –allows one to read a line of letters and numbers varying in
size Informs the pt of visual acuity and how much the cataract has affected vision
–catches visual acuity problems relatively early A large lens machine will be placed in front of your face.
Bring current prescription lenses Patients who are illiterate and do not know the alphabet.
Pt should have good cervical stability (requires leaning forward slightly)
Slit lamp examination Sit in chair with instrument in front. Place chin and forehead on support to keep
steady. Eye drops are instilled Allows HCP to examine your eyes, specifically eyelids, cornea,
conjunctiva, sclera, and iris. A 2nd exam is performed to see the back of the eye Eye drops may be
instilled or a fine strip of paper stained with the dye will be touched to your eye allowing them to dilate
for the HCP to see back of the eye. Bring sunglasses for post procedure as pupils will be dilated. No
absolute contraindications, but pt with open globe injury require extreme caution during examination.
Children may be examined with parental assistance, reassurance, and special

The Perception Of A Infant 's Visual System
The phenomena of perception refer to the sensory processes that enables human beings to recognize and
organized the information that is received from the environment. Such process allows individuals to
perceive the world and objects. For such process to occur, theorists research visual perceptual patterns
during the period of infancy. Research has found that there are differences between the way a newborn
infant perceives the world in comparison to adults, as their visual system is not fully developed at such
an early age. An infant's visual system is heterochronus which disables them from seeing a complete
view of the world, compared to adults.
An individual's visual system is constructed by different components. The eye and the brain perform
different functions and go through different processes from the moment light is reflected from an object
to actually obtaining visual recognition. Vision relies on the response of the nervous system to the light
that has been reflected from an object, during this process many parts of the human eye are active. When
a ray of light enters the pupil of the eye, the cornea refracts the lights and focuses the lights on the lens
which focuses the light at the back of the eye in the retina. The retina then converts the light via optic
nerves which enables the information to be processed in the brain, enabling visual recognition of the
image which we see (Wade, 2001). This process is necessary, so individuals are able to comprehend
what is

Visual Acuity
Visual acuity is a screening procedure that is concentrated on the diagnosis of an illness and measures
visual acuity. This procedure is often done by the medical assistant in a well–light area or room. "The
medical assistant should observe the patient to look for any condition or behavior that could possibly
indicate visual distance, such as tilting the head forward or to the side, excessive blinking or eyes
watering, frowning or puckering the face, closing of one's eyes when testing both of the eyes and signs
of straining to see. Common devices used to measure distant vision is a Snellen chart. This chart will
show the distance an individual can read the chart from. For an individual with reading troubles a chart
with letter E's arranged

Classification System ( 17 ) Essay
All patients were diagnosed with a stage 2, 3, or 4 idiopathic MH according to the Gass classification
system(17) and underwent a comprehensive ophthalmologic examination before and 1, 3, and 6 months
postoperatively, including measurement of the best–corrected VA (BCVA), binocular indirect
ophthalmoscopy, and non–contact lens slit–lamp biomicroscopy. The SD–OCT examination also was
performed in all patients on the same day as the clinical examination. Standard 3–port pars plana
vitrectomy for MH repair consisted of a core vitrectomy with intravitreal injection of triamcinolone
acetonide to visualize the vitreous gel, surgical creation of a posterior vitreous detachment if it had not
yet occurred, ILM peeling using Briliant blue G (BBG), and fluid–gas exchange followed by flushing
with a mixed non–expansile concentration of 20% sulfur hexafluoride. Patients were instructed to
remain facedown for 2 to 7 days postoperatively. Anatomic success was defined as the presence of a flat
or closed MH 1 month postoperatively confirmed by biomicroscopy.(18) All patients provided written
informed consent after they received a detailed explanation of the surgical procedure and SD–OCT
follow–up examinations. Our retina specialist (SB) performed the surgeries. One of two experienced
examiners performed the VA examinations, and experienced technicians conducted the SD–OCT
examinations. The study adhered to the tenets of the Declaration of Helsinki and was approved by the
institutional

Overall Characteristics Of Selected Trials And Quality...
Results Overall Characteristics of Selected Trials and Quality Assessment A total of 1736 articles were
initially identified. Of these, 1687 were excluded according to the exclusion criteria listed above. The 49
remaining articles with full texts that met the inclusion criteria were assessed.11, 14, 17–19, 25 A total of
4 studies were included in this review. One study compared aflibercept with bevacizumab and
ranibizumab for centre–involved DMO using a standardized follow–up and retreatment regimen.17, 18
Due to there being only one study comparing aflibercept with other anti–VEGF agents, it was not
included in the meta–analysis. Figure 1 provides a flow diagram of the search process. In total, there
were 661 patients included in this meta–analysis: 331 patients in the aflibercept group and 330 patients
in the photocoagulation group. The characteristics of the studies included and risk of bias assessment are
summarized in Tables 1 and 2. The DA VINCI study compared photocoagulation with monthly,
bimonthly and as needed or pro re nata (PRN) intravitreous aflibercept regimens. The PRN regimen was
selected for data extraction because this is the current practice with other anti–VEGF drugs. The VISTA
and VIVID studies compared photocoagulation with 4–weekly intravitreous aflibercept (2q4) and a
regimen of five initial 4–weekly intravitreous aflibercept followed by 8–weekly injections (2q8). The
2q8 regimen was selected for data extraction as the total number of injections in

Essay on Visual Acuity as a Function of Retinal Eccentricity
Visual Acuity Measured as a Function of Retinal Eccentricity
Visual acuity is a measure of an observer's ability to see fine spatial detail (Cavonius &
Schumacher, 1966). There are a number of factors that affect visual acuity, such as illumination and
contrast, and various ways to measure it (Kalloniatis & Luu, 2005). One way to measure visual
acuity is through target detection which requires the perception of the orientation of a stimulus such as a
Landolt C or a Snellen E (Kalloniatis & Luu, 2005). The participant in the current experiment was
referred to have their acuity tested. Target detection of a stimulus was used to measure the participant's
visual acuity as a function of retinal eccentricity of the target. ... Show more content on Helpwriting.net
...
The height and width of this optotype is designed to be five times the thickness of the stroke width and
gap width, therefore the size of each critical detail is 1/5th of the overall height (Kalloniatis & Luu,
2005). Four stimulus sizes were used in the experiment as visual acuity was to be tested at four
eccentricities (0˚, 20˚, 40˚ and 60˚). These four stimulus sizes were calculated using the approximate
minimum angle of resolution (MAR) of each eccentricity obtained from Millodot et al.'s (1975) normal
data. This value was then used to find the gap size and hence the stimulus size using a distance of
600cm. The reason for using the distance value of 600cm was because it is close to the threshold and
therefore would be the starting point of stimulus presentation for each of the eccentricities. The formula
used was: gap size = 600*tan(MAR˚) ˃˃ size = 5 (600*tan(MAR˚))
The stimulus sizes (and critical feature sizes) calculated and used for the eccentricities 0˚, 20˚, 40˚ and
60˚ were 0.9cm (0.18cm), 2.2cm (0.44cm), 6.13cm (1.23cm) and 17.5cm (3.5cm) respectively.
Procedure
As already stated, it was decided by the experimenter to test visual acuity at the following eccentricities:
0˚, 20˚, 40˚ and 60˚. Measuring the MAR at each of these eccentricities would give a good indication of
where the participant's visual acuity measure lies in comparison to normal data. Exact vertical and
horizontal

Description Of The Barn Owls Essay
Outline I. Introduction II. Barn Owls a. The Barn Owl is an extremely specialized nocturnal marauder
with exceptional preying skills. b. They are also notorious for their advanced sound–localization
capabilities. c. The visual system in the Barn Owl shows anatomical, purposeful, and physiological
specializations. d. Front Facing Eyes with high–quality optics which create an abnormally large
binocular field of observation which is a sign for increased ethological importance for the use of stereo
vision e. Barn Owls have coupled modification in both eyes and an enlarged Wulst. i. With this comes a
high level of binocular interaction and selectivity for binocular inconsistency. f. Owls have global
stereopsis and use disparity, the inconsistency, as a depth cue with hyperacute exactness. g. Barn Owls
are able to make out illusionary contours. h. Owls have very limited potential in moving its eyes relative
to its head. i. The eyes nor the ears move separately from the head in owls. i. The image quality in the
eyes of the Barn Owl is exceptional. j. III. Vernier Acuity a. Vernier acuity is the capability to identify
tiny spatial offsets in paired lines, dots, or objects. b. Currently, humans can determine the relative
positional alteration of spatially non–aligned features with meticulousness that corresponds to a small
percentage of the eye's resolving power. c. Does the Barn Owl display hyperacuity in a Vernier task? i.
In the experiment, a simple one–up and one–down

Case Study Of Retinitis Pigmentosa

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