The document discusses the optics and use of a lensometer. A lensometer is a device used to measure the refractive power of lenses. It works using the Badal principle, where the eye is placed at the focal point of a lens and the image always subtends the same visual angle. There are manual and automated lensometers. A manual lensometer uses a telescope, target, and power drum to measure spherical and cylindrical lens powers by bringing lines of the target into focus. An automated lensometer uses an LCD monitor, lens plate, and memory buttons to electronically measure lens parameters. Correct use requires focusing the eyepiece and centering lenses to determine their optical power.
Detailed instumentaion and use of manual Lensometer and just a outline of automated lensometer.
I have used the picture of manual lensometer with out the parts describtion because i have explained orally by showing the picture..
Hope u all like it and may help you in learning better. :)
Detailed instumentaion and use of manual Lensometer and just a outline of automated lensometer.
I have used the picture of manual lensometer with out the parts describtion because i have explained orally by showing the picture..
Hope u all like it and may help you in learning better. :)
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Retinoscopy and Objective Refraction and Subjective Refraction in spherical ametropia and astigmatism
Retinoscopy (Principle & Techniques of Retinoscopy) and objective refraction, Subjective Refracition
Best presentation about retinoscopy and objective refraction techniques, and basis of subjective refraction. If you want to master the technique of retinoscopy, this presentation can be your guidance and partner in your journey to retinoscopy, objective refraction and subjective refraction.
Presentation Layout:
Retinoscope, types of retinoscope and uses of retinoscope
-Introduction to retinoscopy and objective refraction
-Retinoscopy
- In spherical ametropia
- In astigmatism
- Others: strabismus, amblyopia, pediatric pt.,
cycloplegic refraction
-Static and Dynamic Retinoscopy
-Problems seeing reflex during retinoscopy
-Errors in retinoscopy
Objective of retinoscopy and objective refraction
-To locate the far point of the eye conjugate to the retina
- Myopia or hyperopia
-Bring far point to the infinity by using appropriate lenses
- Determines amount of ametropia by retinoscopy and objective refraction
References:
-Clinical Procedures in Optometry by Eskridge, Amos and Bartlett ,
-Primary Care Optometry by Grosvenor T.,
-Borish’s Clinical Refraction by Benjamin W. J.,
-Theory And Practice Of Optics And Refraction by AK Khurana
-Retinoscopy-Student Manual by ICEE Refractive Error Training Package (2009)
-Clinical Optics and Refraction By Andrew Keirl, Caroline Christie
-Clinical Refraction Guide - A Kumar Bhootra
-Clinical Procedures in Primary Eye Care by David B. Elliott
-Internet
Follow me to get in touch with optometric and ophthalmic updates.
what is Duochrome Test, Why do we take Red and Green color only,
What is the Principal of Duochrome Test, Why Hyperopic Pt sees green better than red and vice versa
DIRECT DOWNLOAD LINK ❤❤https://healthkura.com/retinoscopy/❤❤
Dear viewers Check Out my other piece of works at ❤❤❤ https://healthkura.com ❤❤❤
Retinoscopy and Objective Refraction and Subjective Refraction in spherical ametropia and astigmatism
Retinoscopy (Principle & Techniques of Retinoscopy) and objective refraction, Subjective Refracition
Best presentation about retinoscopy and objective refraction techniques, and basis of subjective refraction. If you want to master the technique of retinoscopy, this presentation can be your guidance and partner in your journey to retinoscopy, objective refraction and subjective refraction.
Presentation Layout:
Retinoscope, types of retinoscope and uses of retinoscope
-Introduction to retinoscopy and objective refraction
-Retinoscopy
- In spherical ametropia
- In astigmatism
- Others: strabismus, amblyopia, pediatric pt.,
cycloplegic refraction
-Static and Dynamic Retinoscopy
-Problems seeing reflex during retinoscopy
-Errors in retinoscopy
Objective of retinoscopy and objective refraction
-To locate the far point of the eye conjugate to the retina
- Myopia or hyperopia
-Bring far point to the infinity by using appropriate lenses
- Determines amount of ametropia by retinoscopy and objective refraction
References:
-Clinical Procedures in Optometry by Eskridge, Amos and Bartlett ,
-Primary Care Optometry by Grosvenor T.,
-Borish’s Clinical Refraction by Benjamin W. J.,
-Theory And Practice Of Optics And Refraction by AK Khurana
-Retinoscopy-Student Manual by ICEE Refractive Error Training Package (2009)
-Clinical Optics and Refraction By Andrew Keirl, Caroline Christie
-Clinical Refraction Guide - A Kumar Bhootra
-Clinical Procedures in Primary Eye Care by David B. Elliott
-Internet
Follow me to get in touch with optometric and ophthalmic updates.
what is Duochrome Test, Why do we take Red and Green color only,
What is the Principal of Duochrome Test, Why Hyperopic Pt sees green better than red and vice versa
Optometry instruments is a presentation to describe instrument in a beautiful way. use this tool to improve your knowledge. stay blessed. Regards Muhammad Akbar Rashid Qadri.
For generations, the Synoptophore has been THE standard instrument of choice for the busy Orthoptic clinic. It is ideal for the assessment and treatment of ocular motility disorders by reliably performing the most comprehensive binocular vision assessment available today.
Duane syndrome, also called Duane retraction syndrome (DRS), is a congenital and non-progressive type of strabismus due to abnormal development of the 6th cranial nerve.
It is characterized by difficulty rotating one or both eyes outward (abduction) or inward (adduction).
On the other hands Duane Retraction Syndrome is a congenital strabismus syndrome occurring in isolated or syndromic forms. It presents with a variety of clinical features including diplopia, anisometropia, and amblyopia.
Glaucoma is always a chronic, long term disease.
Glaucoma is always associated with some damage to the optic nerve and often a related change in the visual field.
When parallel rays of light enter the eye ((with accommodation relaxed) and do) and do not come to a single point focus on or near the retina.
Types of Astigmatism:
Sign & Symptoms:
Management:
“sturm Conoid is just a representation of how rays are refracted through two different powered meridians” (eg: a sphero- cylindrical lens). So, instead of one focal point, they form two focal lines.
Sturm’s Conoid/Interval:
Etiology of Sturm’s Conoid :
Focus of Sturm’s Conoid AC/to The Types of Astigmatism:
The term ‘‘aniseikonia” comes from the Greek words ‘‘an” (not) ‘‘is” (equal) & ‘‘eikon” (icon or image) so aniseikonia is a binocular condition in which the apparent sizes of the images seen with the two eyes are unequal.
Whenever refractive ametropias in the two eyes of a person are different (i.e., when there is an anisometropia), the corrected retinal images of the two eyes, and consequently the two visual images, differ in size.
This condition has been termed aniseikonia
Optical aniseikonia
Retinal aniseikonia
Cortical aniseikonia
Eyelid Tumours: A swelling of a part of eyelid generally without inflammation caused by an abnormal growth of tissue.
Types:
Benign &
Malignant
Benign tumors:
Epithelial tumors
Melanocytic tumors
Adnexal cystic lesions
Sweat gland origin
Hair follicle origin
Miscellaneous lesions
Vascular Tumours
Neural Tumours
Malignant tumors:
Glaucoma is a group of eye diseases which result in damage to the optic nerve and cause vision loss.
Congenital (Buphthalmos): Congenital glaucoma (CG) is a developmental glaucoma that results from the abnormal development of the aqueous drainage structure, characterized by an elevated intra-ocular pressure, enlargement of globe (buphthalmos), corneal edema and optic nerve cupping, and presenting clinically with the characteristic triad of epiphora, photophobia and blepharospasm.
Glaucoma is one of the leading causes of blindness for people over the age of 60.
Vision charts/Eye Charts/Acuity chartsAzizul Islam
Visual acuity charts is an eye sight test charts.It is a clinical examination charts used by orthoptists, optometrists and ophthalmologists to determine a patient’s visual acuity (Near & Distance).
A Snellen chart is an eye chart that can be used to measure visual acuity. Snellen charts are named after the Dutch ophthalmologist Herman Snellen.
Snellen chart used for visual testing. Uses, Vision testing.
Landolt C · Lea test · logMAR chart ...
Retinoblastoma (RB) is a rare form of cancer, that rapidly develops from the immature cells of a retina ( the light-detecting tissue of the eye). It is the most common primary malignant intraocular cancer in children.
Cancer of the Eye
Diagnosis: Birth-~6 years olds
Unilateral or Bilateral
~3% of Pediatric Cancers
Brückner, in 1962, published a paper in German describing a "trans-illumination" test extremely useful in the diagnosis of small angle deviations and amblyopia in young uncooperative children. A bright coaxial light source, such as a direct ophthalmoscope, is used.
The visual pathway/visual system is the part of central nervous system which gives organisms the ability to process visual detail , as well as enabling the formation of several non-image photo response functions.
It detects interprets information from visible light to build a representation of the surrounding environment .
The visual system carries out a number of complex tasks , including the reception of light and the formation of monocular representations; the buildup of a nuclear binocular perception from a pair of two dimensional projections ; the identification and categorization of visual objects ; assessing distances to and between objects and guiding body movements in relation to the objects seen.
Neuro-Ophthalmology: is the specialty that is concerned with visual symptoms resulting from brain diseases. The visual symptoms can be divided into visual loss, or problems with eye movements. Visual loss may result from problems within the optic nerve or its connections to the visual portions of the brain.
History Record of neuro ophthalmological patient.
structure of eye ball,eyeball is a specialized sense organ that helps us to understand our environment. It is a sensory unit composed of three parts: receptor, sensory pathway, and a brain center
The main parts of the human eye are The Conjunctiva,
Sclera,Choroid,
Cornea, Iris, Pupil,
Anterior Chamber,
Posterior Chamber, Aqueous humor, Lens, Vitreous humor, Retina,Macula and Optic nerve.
Why we prescribe glass…
Able to detect hypermetropia & myopia…
Subjective correction child patient…
The sequence of prescription writing…
Practical events of glass prescription writing procedure
Conjunctivitis is an inflammation or swelling of the conjunctiva. Often called "pink eye," conjunctivitis is a common eye disease, especially in children. It may affect one or both eyes.
To Know about Extra Ocular muscles
To Know about Ocular Motility & Laws of OM
To Know various Cardinal Gaze of OM
An Idea OM Disorder (Children+ Adult)
Treating protocol OM Disorder
Antibiotic Stewardship by Anushri Srivastava.pptxAnushriSrivastav
Stewardship is the act of taking good care of something.
Antimicrobial stewardship is a coordinated program that promotes the appropriate use of antimicrobials (including antibiotics), improves patient outcomes, reduces microbial resistance, and decreases the spread of infections caused by multidrug-resistant organisms.
WHO launched the Global Antimicrobial Resistance and Use Surveillance System (GLASS) in 2015 to fill knowledge gaps and inform strategies at all levels.
ACCORDING TO apic.org,
Antimicrobial stewardship is a coordinated program that promotes the appropriate use of antimicrobials (including antibiotics), improves patient outcomes, reduces microbial resistance, and decreases the spread of infections caused by multidrug-resistant organisms.
ACCORDING TO pewtrusts.org,
Antibiotic stewardship refers to efforts in doctors’ offices, hospitals, long term care facilities, and other health care settings to ensure that antibiotics are used only when necessary and appropriate
According to WHO,
Antimicrobial stewardship is a systematic approach to educate and support health care professionals to follow evidence-based guidelines for prescribing and administering antimicrobials
In 1996, John McGowan and Dale Gerding first applied the term antimicrobial stewardship, where they suggested a causal association between antimicrobial agent use and resistance. They also focused on the urgency of large-scale controlled trials of antimicrobial-use regulation employing sophisticated epidemiologic methods, molecular typing, and precise resistance mechanism analysis.
Antimicrobial Stewardship(AMS) refers to the optimal selection, dosing, and duration of antimicrobial treatment resulting in the best clinical outcome with minimal side effects to the patients and minimal impact on subsequent resistance.
According to the 2019 report, in the US, more than 2.8 million antibiotic-resistant infections occur each year, and more than 35000 people die. In addition to this, it also mentioned that 223,900 cases of Clostridoides difficile occurred in 2017, of which 12800 people died. The report did not include viruses or parasites
VISION
Being proactive
Supporting optimal animal and human health
Exploring ways to reduce overall use of antimicrobials
Using the drugs that prevent and treat disease by killing microscopic organisms in a responsible way
GOAL
to prevent the generation and spread of antimicrobial resistance (AMR). Doing so will preserve the effectiveness of these drugs in animals and humans for years to come.
being to preserve human and animal health and the effectiveness of antimicrobial medications.
to implement a multidisciplinary approach in assembling a stewardship team to include an infectious disease physician, a clinical pharmacist with infectious diseases training, infection preventionist, and a close collaboration with the staff in the clinical microbiology laboratory
to prevent antimicrobial overuse, misuse and abuse.
to minimize the developme
How many patients does case series should have In comparison to case reports.pdfpubrica101
Pubrica’s team of researchers and writers create scientific and medical research articles, which may be important resources for authors and practitioners. Pubrica medical writers assist you in creating and revising the introduction by alerting the reader to gaps in the chosen study subject. Our professionals understand the order in which the hypothesis topic is followed by the broad subject, the issue, and the backdrop.
https://pubrica.com/academy/case-study-or-series/how-many-patients-does-case-series-should-have-in-comparison-to-case-reports/
R3 Stem Cells and Kidney Repair A New Horizon in Nephrology.pptxR3 Stem Cell
R3 Stem Cells and Kidney Repair: A New Horizon in Nephrology" explores groundbreaking advancements in the use of R3 stem cells for kidney disease treatment. This insightful piece delves into the potential of these cells to regenerate damaged kidney tissue, offering new hope for patients and reshaping the future of nephrology.
We understand the unique challenges pickleball players face and are committed to helping you stay healthy and active. In this presentation, we’ll explore the three most common pickleball injuries and provide strategies for prevention and treatment.
Navigating Challenges: Mental Health, Legislation, and the Prison System in B...Guillermo Rivera
This conference will delve into the intricate intersections between mental health, legal frameworks, and the prison system in Bolivia. It aims to provide a comprehensive overview of the current challenges faced by mental health professionals working within the legislative and correctional landscapes. Topics of discussion will include the prevalence and impact of mental health issues among the incarcerated population, the effectiveness of existing mental health policies and legislation, and potential reforms to enhance the mental health support system within prisons.
CHAPTER 1 SEMESTER V PREVENTIVE-PEDIATRICS.pdfSachin Sharma
This content provides an overview of preventive pediatrics. It defines preventive pediatrics as preventing disease and promoting children's physical, mental, and social well-being to achieve positive health. It discusses antenatal, postnatal, and social preventive pediatrics. It also covers various child health programs like immunization, breastfeeding, ICDS, and the roles of organizations like WHO, UNICEF, and nurses in preventive pediatrics.
Global launch of the Healthy Ageing and Prevention Index 2nd wave – alongside...ILC- UK
The Healthy Ageing and Prevention Index is an online tool created by ILC that ranks countries on six metrics including, life span, health span, work span, income, environmental performance, and happiness. The Index helps us understand how well countries have adapted to longevity and inform decision makers on what must be done to maximise the economic benefits that comes with living well for longer.
Alongside the 77th World Health Assembly in Geneva on 28 May 2024, we launched the second version of our Index, allowing us to track progress and give new insights into what needs to be done to keep populations healthier for longer.
The speakers included:
Professor Orazio Schillaci, Minister of Health, Italy
Dr Hans Groth, Chairman of the Board, World Demographic & Ageing Forum
Professor Ilona Kickbusch, Founder and Chair, Global Health Centre, Geneva Graduate Institute and co-chair, World Health Summit Council
Dr Natasha Azzopardi Muscat, Director, Country Health Policies and Systems Division, World Health Organisation EURO
Dr Marta Lomazzi, Executive Manager, World Federation of Public Health Associations
Dr Shyam Bishen, Head, Centre for Health and Healthcare and Member of the Executive Committee, World Economic Forum
Dr Karin Tegmark Wisell, Director General, Public Health Agency of Sweden
Leading the Way in Nephrology: Dr. David Greene's Work with Stem Cells for Ki...Dr. David Greene Arizona
As we watch Dr. Greene's continued efforts and research in Arizona, it's clear that stem cell therapy holds a promising key to unlocking new doors in the treatment of kidney disease. With each study and trial, we step closer to a world where kidney disease is no longer a life sentence but a treatable condition, thanks to pioneers like Dr. David Greene.
Welcome to Secret Tantric, London’s finest VIP Massage agency. Since we first opened our doors, we have provided the ultimate erotic massage experience to innumerable clients, each one searching for the very best sensual massage in London. We come by this reputation honestly with a dynamic team of the city’s most beautiful masseuses.
Defecation
Normal defecation begins with movement in the left colon, moving stool toward the anus. When stool reaches the rectum, the distention causes relaxation of the internal sphincter and an awareness of the need to defecate. At the time of defecation, the external sphincter relaxes, and abdominal muscles contract, increasing intrarectal pressure and forcing the stool out
The Valsalva maneuver exerts pressure to expel faeces through a voluntary contraction of the abdominal muscles while maintaining forced expiration against a closed airway. Patients with cardiovascular disease, glaucoma, increased intracranial pressure, or a new surgical wound are at greater risk for cardiac dysrhythmias and elevated blood pressure with the Valsalva maneuver and need to avoid straining to pass the stool.
Normal defecation is painless, resulting in passage of soft, formed stool
CONSTIPATION
Constipation is a symptom, not a disease. Improper diet, reduced fluid intake, lack of exercise, and certain medications can cause constipation. For example, patients receiving opiates for pain after surgery often require a stool softener or laxative to prevent constipation. The signs of constipation include infrequent bowel movements (less than every 3 days), difficulty passing stools, excessive straining, inability to defecate at will, and hard feaces
IMPACTION
Fecal impaction results from unrelieved constipation. It is a collection of hardened feces wedged in the rectum that a person cannot expel. In cases of severe impaction the mass extends up into the sigmoid colon.
DIARRHEA
Diarrhea is an increase in the number of stools and the passage of liquid, unformed feces. It is associated with disorders affecting digestion, absorption, and secretion in the GI tract. Intestinal contents pass through the small and large intestine too quickly to allow for the usual absorption of fluid and nutrients. Irritation within the colon results in increased mucus secretion. As a result, feces become watery, and the patient is unable to control the urge to defecate. Normally an anal bag is safe and effective in long-term treatment of patients with fecal incontinence at home, in hospice, or in the hospital. Fecal incontinence is expensive and a potentially dangerous condition in terms of contamination and risk of skin ulceration
HEMORRHOIDS
Hemorrhoids are dilated, engorged veins in the lining of the rectum. They are either external or internal.
FLATULENCE
As gas accumulates in the lumen of the intestines, the bowel wall stretches and distends (flatulence). It is a common cause of abdominal fullness, pain, and cramping. Normally intestinal gas escapes through the mouth (belching) or the anus (passing of flatus)
FECAL INCONTINENCE
Fecal incontinence is the inability to control passage of feces and gas from the anus. Incontinence harms a patient’s body image
PREPARATION AND GIVING OF LAXATIVESACCORDING TO POTTER AND PERRY,
An enema is the instillation of a solution into the rectum and sig
2. Lensometer is also known as Focimeter or avertometer
(The main use of the lensometer is to measure the back
or front vertex power of a spectacle lens.
It is a device designed to measure the refractive power
prescription of a unknown lens. (spherical, cylindrical
with axis and also the optical center)
Types:-
Manual
Automated
LENSOMETER
Manual
Automated
N.B: The lensometer works on the Badal principle with the addition of
an astronomical telescope for precise detection of parallel rays at
neutralization.
The Badal principle is Knapp’s law applied to lensometers. IIEI&H
3. The Badal principle (Ogle, 1968; Southall, 1964) is based on the observation that if the eye is placed at the
focal point of a positive lens, the virtual image of an object located between the lens and the anterior focal
point will always subtend the same visual angle.
Badal optics are disclosed in which an aperture array at an optical system under test is interrogated for the
deflection of light between a detector array conjugate with the aperture array of the optical system under test
being examined. Excursion is measured in a plane normal to the axis of the Badal optics instead of observing
towards and away image focus along the axis of the Badal system.
In the case of an objective refractor, the eye is illuminated at the retina with a test spot, preferably light in the
infrared. An image of a detector array is relayed by a relay lens through the Badal optics to the cornea of the
eye, the lens under test. Light emanating from the test spot on the retina passes through the eye lens at the at
the image of the detector array. This light undergoes excursion in accordance with the power of eye lens under
test at each aperture of the detector array.
The extent of this excursion is determined by a moving boundary locus between the image of the detector
array and the detector array itself. This excursion is related directly to the eye prescription.
Badal principle
IIEI&H
6. General Description of the Lensometer
1. The eyepiece
2. Chrome Knurled Sleeve
3. Prism Compensating Device Knob
4. Lens Holder Handle
5. Marking Device Control
6. Gimbal
7. Ink Pad
8. Spectacle Table Lever
9. Spectacle Table
10. Power Drum
11. Locking Lever
12. Prism Axis Scale
13. Prism Compensating Device
14. Prism Diopter Power Scale
15. On-off Switch
16. Lens Stop
17. Cylinder Axis Wheel
18. Filter Lever
19. Lamp Access Cover IIEI&H
7. 1. The Eyepiece : mounted in a screw-type focusing mechanism, the eyepiece
plays an important role in the accuracy of your readings. It is essential that the
eyepiece be focused to the individual eye of each user. It may be fitted with a
rubber guard to prevent scratching of the user’s own eyewear.
2. Chrome Knurled Sleeve: used to rotate the Reticle to orient prism base.
3. Prism Compensating Device Knob: Used to read prism amounts greater than
five prism diopters.
4. Lens Holder Handle :Used to hold a lens in place against the aperture.
5. Marking Device Control: Used to spot the lens at either the Optical Center or
Prism Reference Point (PRP).
6. Gimbal: A pivoting holder that holds the lens in place.
7. Ink Pad: Holds the spotting ink.
8. Spectacle Table Lever: Used to raise, or lower the level of the Spectacle Table.
IIEI&H
8. 9. Spectacle Table: The resting place for the frame when neutralizing finished eyewear.
10. Power Drum :Hand wheel with numbered scale readings between +20 and -20
Diopters.
11. Locking Lever: Used to elevate or depress the position of the instrument for
individual’s height or posture.
12. Prism Axis Scale: Used for orientation of prism axis
13. Prism Compensating Device: Used to verify or layout large amounts of prism.
14. Prism Diopter Power Scale: Displays prism amount.
15. On-off Switch : Power switch.
16. Lens Stop : Aperture against which the lens rests.
17. Cylinder Axis Wheel: Used to orient or neutralize cylinder axis.
18. Filter Lever: Used to engage or remove green filter.
19. Lamp Access Cover: Provides access to change the lensmeter bulb.
IIEI&H
13. Rotate the eyepiece until fully extended from the
instrument(usually by rotating the eyepiece as far as
possible in an anti clock wise direction).
The graticule visible through the eyepiece will now
appear blurred. The eyepiece should then be rotated
in a clock wise direction until the target cross hairs
and the graticule just come into focus.
Continued rotation of the eyepiece will force the
observer to accommodate in order to keep the
graticule in focus.
With the power wheel at the zero position, the cross
hairs and the target should be in clear focus. Failure
to focus the eyepiece will result in incorrect
readings of lens power.
Procedure Focusing the Eyepiece
IIEI&H
14. Focus the eyepiece of the lensometer for the examiner’s eye
With the power wheel set on zero, turn the eyepiece as far
counter-clockwise as possible
Then slowly turn it clockwise until the reticule first comes
into sharp focus
Insert the spectacles
If testing a pair of glasses, always check the right lens first
Place the pair of glasses in the lensometer with the ocular
surface away from you
The lens is held in place by the lens holder and is held level
on the lens table
Center the lens by moving it so that the image of the
lensometer target is aligned in the center of the eyepiece
reticle
Lens Measurement Preparation
IIEI&H
15. If all the lines or dots of the target are in focus at a
given setting of the power wheel, the lens is spherical,
Marking the optical centre
1. Check that the centre of the lens coincides with the
centre of the target.
2. When this is so, the lens is correctly positioned and
the optical centre could be marked.
3. While there is no centre dot, the whole set of dots
can be ‘framed’ within the lines of the graticule to
locate the centre.
4. Repeat the same procedure for the other lens.
Determining the Lens Power
(Spherical Lenses)
IIEI&H
16. Step 1 (finding the sph: power) : Rotate the power wheel until one set of lines (stretched
dots) becomes clear. Start with the higher positive power (or lower negative power). The
axis drum will need to be rotated to ensure that the lines are unbroken. Note the power on
the power wheel.
Step 2 (finding the cyl: power): Rotate the power wheel until the second set of lines
(stretched dots)becomes clear. The second power reading minus the first reading will
give the power of the cyl (and its correct sign).
Step 3 (finding the axis) : Note the direction of the lines (stretched dots) at the second
reading.This is the axis. The rotatable line in the graticuleis used to line up with the
stretched dots to determine the axis.
Determining the Lens power
(Sphero-Cyllinder)
IIEI&H
18. Take Home Messages
IIEI&H
Always focus the eyepiece before using the instrument
Concentrate on the central circular orientation of dots
(especially in case of toric lenses)
One meridian of the target should always be parallel to
the orientation of central small lines (in toric lens)
Each dot at the center will not be round, instead they will
be small lines oriented in one particular meridian
Except the protractor, everything will be blur when a lens
is placed
The target moves with the movement of the lens
Instrument should not be used more on battery
19. References
Theory and Practice of Optics & Refraction, A. K. Khurana
Lensometry manual by Mr.Sunny Mannava (HCU).
Optical-Dispensing, Arvindo eye care (Gide)
Picture: Me,Book,Google .
IIEI&H