Pathological conditions.pdf

DESCRIPTION –
Achromatopsia is a hereditary conditions in which the cones have
not developed properly leads to an absence of colour description.
There are two types of achromatopsia :
1. Rod monochromatism,which is true color blindness.
2. Blue cone monochromatism,which is caused by a loss of red
and green cones.
ETIOLOGY –
Rod monochromatism is the most common form of achromatopsia
and is transmitted as an autosomal recessive trait.
Blue cone monochromatism is transmittedas an X- linked recessive
inherited person & symptoms to be milder than rod
monochromatism.

INCIDENCE –
This condition is found in 3 of 100000 males.
Occurance of females is slightly less.
VISUAL ACUITY –
Distance VA ranges from 20/60 to 20/200.
Vision is beeter in dim illumination & wosre in bright
illumination.
VISUAL FIELDS –
Visual fields are usually normal but can be slightly
constricted, particularly to colours.

OCULAR SINGS AND SYMPTOMS-
Absence of cones results in reduced central VA in bright
light, decrease in color perception and photophobia.
Pendular nystagmus
Pupils react sluggishly to light .
These pt. Typically have blond fundi and fine disturbances
of retinal pigment epithelium in the macula.
ADJUNCT TESTING –
Electrodiagnostic testing results normal EOG & scotopic
ERG & subnormal photopic ERG responses.
Color testing, Diagnostic this condition.
Fluorescein angiography may show mild hyper
fluorescence when, RPE is abnormal.

LOW VISION MANAGEMENT –
The patient will function better in an environment with
reduced illumination.
Filters, tints, and sunglasses aids in decrease illumination
both indoors and outdoors.
Side shields on a spectacle frame along with hats with large
brims may be helpful for outdoors.
Red tinted contact lenses & red sun lenses hv been used to
reduce photophobia.
Magnification devices for distance and near are also helpful
in these patients.

AGE RELATED
MACULAR
DEGENERATION

DESCRIPTION –
ARMD is an acquired retinal disorder i.e. Caused by
degenerative changes in the RPE with subsequent
degeneration of the overlying cones and rods.
ARMD results in progressive, irreversible loss of central
vision from fibrous scarring or geographic atrophy of the
macular area.
ETIOLOGY –
There are defects in the processing of photoreceptor outer
segments by the RPE as well as a deposition of abnormal
material within the RPE & underlying Bruch’s membrane.
It appears hereditary and genetic factors predispose certain
eyes.

RISK FACTORS –
A no. Of ocular, systemic, behavioural and genetic,
environmental & family history, risk factors for the
development of ARMD.
Hypermetropia, increased cup disc ratio, increased serum
cholesterol level and hypertension, smoking, sunlight
exposure.
INCIDENCE AND PREVALENCE –
It is the second leading cause of Legal blindness in the
United States.
It is the leading cause in individuals older than 65 yrs.
ARMD increases with age and commonly affected women
than males.
It seems to be more frequently seen in white than in blacks.

VISUAL ACUITY –
VA may vary with severity of degeneration.
With dry ARMD,acuity can range from 20/20 to 20/400 .
With wet ARMD,acuity can show loss worse than 20/400.
Approx.750000 Americans haveVA worse than 20/200 in one eye
or both,a result of ARMD.
VISUAL FIELDS(VF) –
VF shows a central or paracentralscotoma with normal peripheral
findings.
It may be completely asymptomatic.
Blurred vision, metamorphopsia,micropsia or a central scotoma
are the first symptoms in wet ARMD.
Patients , visual complaints,need for increased light intensity to
read,fading of vision after a few minutes in bright light and easy
fatigability while during close work.

1. Visual hallucinations, seeing people’s, animals or objects, in bilateral
ARMD.This hallucinations us k/as Charles – Bonnet syndrome.
Dry stage-
It may include Dryden or RPE abnormalities or both.
Due to an abnormal underlying Bruch’s mem. Associated with drusen,
development of choroidal neovascularization (CNV) in patients.
RPE alterations occuring as dry ARMD consist of geographic atrophy,
reticular degeneration, other pigmentary changes.
Wet stage-
It includes gray RPE discoloration, sun RPE elevation, sunretinal or retinal
exudate, or hemorrhage, subretinal fluid in the macular area.
In many eyes, fibrovascular tissue scar formation within Bruch’s membrane
or under the retina, k/as disciform scar, with the overlying retina
undergoing cystic degeneration.

ADJUNCTTESTING –
Scotoma/ distortion can be mapped on an amsler grid.
ICG angiographymay be indicated CNV Associated with PED,
recurrent CNV , poor media quality dur to cataract,blood in the
vitreous,exudative material.
Angiography resultsvhelp to determine whether the pt.Would
benefit from laser treatment of CNV.
PROPHYLAXIS –
The age related eye disease study has been initiated & is currently
in progress to evaluate whether dietary supplementation with high
dose of antioxidants shows the onset/progression of macular
degeneration or lens opacities or both.
UV and visible blue light blocking lenses can be prescribed for
aphakia,pseudophakia,young patients with a family history of
ARMD.

Increased direct illumination should be recommended for
all near tasks.
Most patients respond well to magnification at distance and
near.
Optical and non optical devices, filters, tints, sunlenses for
improved contrast, glare and photophobia should be
evaluated.
In addition to optical and non optical devices, patients or
family involvement, or both, in a support group may be
beneficial.

DESCRIPTION-
It is a congenital condition characterizedby lack of pigment or the
body’s inability to produce pigment.
It can occur as oculocutaneousalbinism,in which the skin, hair and eyes
are affected or as ocular albinism,which only involved the eyes.
ETIOLOGY –
Oculocutaneousalbinism may be inherited as either an autosomal
recessive Or autosomal dominant trait.
Patients with recessive form,can have either the tyrosinasepositive &
negative form.
Ocular albinism is usually inheritedvas an X linked recessive trait.
Females are carrier,have hypopigmentationscattered among areas of
normally pigmented retina.

In oculocutaneous albinism, is reduction in the amount of
pigment (melanin) in each eye of the pigment melanosomes.
In Ocular albinism, is reduction in the no. Of melanosomes.
INCIDENCE –
It occurs in 1 in 20000 individuals in the general population.
Ocular albinism occurs in 1 in 40000.
VISUAL ACUITY –
VA range from 20/200 to 20/400.
In ocular albinism,VA is usually 20/25 to 20/100.
Visual acuity does not appear to improve greatly with age.
VISUAL FIELDS –
VF are full,without defects in all forms of albinism.

SYSTEMIC SIGNS AND SYMPTOMS –
It is the result of decresed pigmentation that can affect
the skin , hair ,eyes.
OCULAR SIGNS AND SYMPTOMS –
These patients have white eyebrows, and eyelashes, light
blue irises, photophobia.
Macular hypoplasia/ complete aplasia resulting in
reduced VA & pendular nystagmus and high refractive
errors.
Poor stereopsis, resulting in high incidence of
strabismus.
Absence of foveal reflex and depigmented fundus.

ASSOCIATED SYNDROMES –
1. Yellow mutant oculocutaneous albinism,pts.Gradually accumulate
pigment & yellow- red hair with cream yellow skin.
2. Albinoidism,pts.Often sunburn easily but have goodVA & no
nystagmus but foveal reflex are full are common.
3. Hermansky-Pudlaksyndrome
4. Chediak-Higashi syndromE
ADJUNCTTESTING –
The hair bulb test to distinguish b/w tyrosinasenegative & positive
albinism.
Hairs epilated from the scalp are incubated in tyrosine solution.

Initially, corrective refractive errors and reduce
nystagmus.
Controlling illumination with sun lenses, tints & UV
protection, apertures or colored contact lenses, visors &
hats often reduce photophobia.
Genetic counseling is also indicated.
Albinotic patients are ideal candidates for magnification
due to the absence of Central or peripheral visual field
defects.

DESCRIPTION –
It implies absence of iris.
This is a bilateral anomaly, which has a tendency to form
peripheral anterior synechia.
ETIOLOGY –
It is a congenial anomaly that develops 12th week of gestation.
2/3rd of the cases are inhereted in the autosomal dominant
fashion.
1/3rd remaining cases appear spontaneous mutation.
INCIDENCE –
It is found in 1 in 50000-100000 of the population.

VISUAL ACUITY –
VA, range from 20/100-20/400 associated with macular
hypoplasia.
VISUAL FIELDS –
It may occur due to secondary glaucoma.
SYSTEMIC SIGNS & SYMPTOMS –
Significant associated with kidney tumour, genitourinary
abnormalities & mental retardation are found with ANIRIDIA.
OCULAR SIGNS & SYMPTOMS –
photophobia due to their enlarged pupillary apertures.
Microcornea with peripheral Corneal pannus, which
extends centrally causing Corneal opacification, cataract &
lens dislocation .

Glaucoma, macular hypoplasia, sensory nystagmus & optic
nerve hypoplasia may also be seen in case of aniridia.
ASSOCIATED SYNDROME –
Miller’s syndrome.
MEDICAL TREATMENT –
Medical therapy should be prescribed to control IOP.
Goniotony be performed to prevent blackage of trabecular
meshwork by iris adhesion.
Cyclocryotherapy may be preferred for advanced
glaucoma.
Corneal transplantation due to opacification.
Cataract extraction i.e. IOL implantation.

Pupillary apeeture controls contact lenses reduce
photophobia & may be improve VA & decrease nystagmus.
In some patients, contact lenses may be contraindicated if
the cornea is compromised.
Magnification devices for visual enhancement for distance &
near.
Uses of sunlenses, filters.
Genetic counseling is extremely important.
PROGNOSIS –
Secondary glaucoma in pts.With ANIRIDIA is difficult to
manage & can lead to blindness .

DESCRIPTION –
It is a congenial notch i.e. A defect in the closure of the
embryonic cleft.
The optic nerve, choroid, retina can be involved posteriorly.
Anteriorly, the defect can extend forward & affect the iris.
ETIOLOGY –
A no. Of cases in which sporadic, non inherited colobomas can
be acquired in association with chromosomal abnormalities.
INCIDENCE –
Commonly bilateral.

VISUAL ACUITY –
VA range from normal to 20/400, depending on the extent & location of
the colobomas.
If coloboma involves the optic nerve, vision is usually 20/200 or worse.
VISUAL FIELDS –
Coloboma located in the posterior pole may result in superior visual
field loss.
Iris coloboma appears as an inferior, keyhole- shaped pupil, glare
induces.
Optic nerve coloboma appears as an excavation within the nerve head,
induce retinal detachment.
Retinochoroidal coloboma, where sensory retin is present but RPE and
choroid are absent. STRABISMUS and nystagmus commonly seen.

▪Trisomy13- Colobona is associated with chromosomal
disorder In almost 100%cases. Failure to thrive results in
death with in 1st months of life.
▪ Aicardi’s syndrome- severe mental retardation.
▪ Goldenhar’s syndrome- coloboma, dermoids,
microphthalmia, preauricular skin, main features of this
disorder.Vertebral, cardiovascular, renal and genitourinary
anomalies may also be present.
▪ Charge- coloboma, heart disease, genital hypoplasia and ear
anomalies.
Renal detachment and retinal breaks associated with
colobomas require surgical repair.

Initially, refractive errors should be investigated.
Aperture control or painted iris contact lenses can help with
cosmesis & glare caused by coloboma.
CPF filters, sunlenses are also helpful for glare & photophobia.
Patients may function better in environment with reduced
illumination & magnification is high.
Mobility is generally unaffected by superior field loss caused
by posterior coloboma, pt. Can be instructed to scan the
environment to avoid superior obstruction.
PROGNOSIS –
Colobomas generally stable, but complications such as retinal
detachment & neovascularization, should be monitored
routinely.

DESCRIPTION –
Corneal dystrophy is a bilateral inherited eventually that
begins in early life & is usually progressive.
ETIOLOGY –
Most Corneal dystrophies are inherited in an autosomal
dominant fashion.
VISUAL ACUITY –
VA range from normal to light perception depending on the
type of dystrophy & the severity of the condition.
VISUAL FIELD –
Usually unaffected by dystrophy but may show generalized
depression depending on severity.

Lattice dystrophy and central crystalline dystrophy may be
associated by systemic disease.
Lattice dystrophy, amyloid deposits b/w the epithelium,
bowman layer .
Central dystrophy, ring shaped crystalline opacities in the
central cornea, associated with systemic hyperlipidemia.
Corneal opacification, recurrent corneal erosion,
astigmatism, nystagmus & strabismus.
Lacrimation, photophobia, monocular diplopia, foreign body
sensation & pain are common symptoms due to this
dystrophy.

Corneal erosion may be treated with antibiotics,
cycloplegics & a bandage contact lens or pressure patch.
Lubricating drops or hyoerosmotic agents may be recurrent
erosion.
Penetrating keratoplasty, when Corneal dystrophy becomes
severe.
Refractive error should be investigated carefully.
Pinhole spectacle lenses & aperture control contact lenses
can reduce aberrations & ghost images.
Sunlenses, tints, filters, visors are helpful in reducing glare &
photophobia for both indoors & outdoors.

Non optical systems , such as large print reading
material , bold line writing paper, & a typoscope, may
be helpful.
Magnification devices should also be prescribed.
PROGNOSIS –
It is generally a slow progressive condition, which can
be visually devastating idmf severe.

DESCRIPTION –
It is defined as opacification of the crystalline lens, which is
classified by anatomic locations of the opacity.
The types include anterior & posterior subcapsular,anterior
& posterior cortical, equatorial & nuclear.
ETIOLOGY –
It is traumatic, metabolic, toxic, pharmacologic,
inflammatory,. Hereditary, & most commonly age related.
In normal lens, metabolic activity includes transport of
aminoacids & cations across the lens epithelium &
synthesisvof protein in the lens fibre.
Any discruption of this metabolic process may lead to
opacification of the lens & associated decreased vision.

INCIDENCE –
Approx. 95%of individuals older than the age of 65 yrs. Hv some form
of cataract.
VISUAL ACUITY –
VA varies greatly depending on the degree & location of opacity.
VA ranges from normal to severe vision impairment.
VISUAL FIELD –
Central & peripheral field testing generally show a relative
generalized depression without focal defects.
Retinoscopy may reveal a dull or abnormal reflex, severity & location
determines by slit lamp, & leukocoria seen in mature cataracts.
Glare & decreased vision, distortion & monocular diplopia & color
discrimination by yellowish color of the lens from opacity.

ADJUNCT TESTING –
Interferometry or potential acuty meter(PAM) or both,to
assess postoperative potential visual acuity.
USG, provides information regarding retinal integrity in the
presence of dense media opacity, which obscures
visualisation of the retina.
Glare & blurring may eliminate with use of mydriatics.
Surgical removal of the lens.
Flare can be reduced by filters, tints, sunlenses.
Non optical systems, such as large print reading material ,
bold line writing paper, & a typoscope may be helpful.

DESCRIPTION –
Subluxation of the lens is a partial dislocation i.e. Caused by weakened,
stretched, or broken zonules.
Upward, downward or lateral displacement can occur.
ETIOLOGY –
It can be hereditary & may be associated with systemic abnormalities .
OCULAR trauma can cause rupture of the zonules resulting in lens
dislocation.
Intraocular inflammation, buphthalmos, & HMSC can cause a secondary
spontaneous lens dislocation.
VISUAL ACUITY –
VA ranges from normal to severe impairment depending on lens
position.
Functional aphakia can produced if the lens is dislocated.

VISUAL FIELD –
VF defects may occur due to lens induced secondary
glaucoma.
SPHERICAL & astigmatic refractive error, monocular
diplopia, loss of accommodation can occur vdue to lens
dislocation.
Sec glaucoma may result from pupillary block, &
Iridodonesis due to zonukar disruption.
Treatment of sec. Glaucona, followed by iridectomy &
lensectomy.
Lensectomy, if anterior lens displacement poses threat of
corneal compromise.

High plus lenses, form of spectacle lenses or aohakic contact
lens, if an aphakic situation is created by lens dislocation.
Plus addition lenses or magnifier may be necessary for near
tasks due to loss of accommodative ability.
Filters & sunlenses, reduced illumination levels.
If diplopia exists, can be eliminated by pinhole lenses,
stenopeic slits or aperture control contact lenses. &
increased transmission of uv lights, can be reduced by UV
coating of spectacle lens.
PROGNOSIS –
Patients are advised against participating in sports or any
activity that could cause total lens dislocation.

DESCRIPTION –
It is a highly specific vascular complication of both eye type I
(juvenile or IDDM) & type II ( age related or NIDDM) diabetes
mellitus.
It is the leading cause of new cases of blindness .
ETIOLOGY –
In DR, the supporting cells of the retinal capillaries die off, thereby
weakening the capillary wall & allowing formation of
microaneurysms.
With progression, blood retina barrier breakdown, which allows
blood constitute to leak or rupture into the retina.
This decrease the retinal integrity both by a physical change(
oedema) or nutritional deprivation or both, which leads to ischemia
& neovascularization.

Morphological changes include microaneurysms, dot
hemorrhage,. Cotton wool spots, venous abnormalities,
intraretinal microvascular abnormalities, retina & iris
neovascularization.
INCIDENCE –
After a 29 yr duration of diabetes, nearly all patients with
IDDM & more than 60% of patients with NIDDM have some
degree of retinopathy.
VISUAL ACUITY –
VA ranges from 20/20 to total blindness.
VISUAL FIELD –
In proliferative disease, retinal ischemia, laser scars, &
retinal detachment can cause corresponding field loss.

SYSTEMIC SIGNS & SYMPTOMS –
Excessive thirst, excessive urination, excessive hunger,
excessive fatigue, weight loss, recurrent infections & slow
healing.
Early NPDR- microaneurysms, hemorrhage, venous
bleeding & IRMAs.
Severe NPDR- microaneurysms, hemorrhage,venous
bleeding in 2or more quadrant or IRMA In quadrant.
Macular edema, thichening of the retina,.
Patients with diabetic retinopathy are decresed, fluctuating
or distorted vision, accommodative insufficiency, increased
time required for dark adaptation, loss of color vision and
floaters.

ADJUNCT TESTING –
Progression of NPDR to PDR identified by fluorescein
angiography.
Capillary loss & dilation& leakage of fluorescein are risk
factors for progression.
Clinical fundus examination can allow the doctor to identify
the risk of progression.
Surgical treatment- focal laser photocoagulation therapy
Panretinal photocoagulation reduces the risk of severe
vision loss from high risk PDR.
Vitrectomy, indicated in case of severe proliferative
retinopathy.

Refractive errors should be checked.
CPFs & sunlenses that block blue wavelength may improve contrast &
eliminate glare & photophobia.
A flash light is helpful if s patient have poor night vision.
Orientation & mobility training is indicated as the condition
progresses & peripheral VF as well as central field defects.
Distance & near devices also useful for magnification.
Non optical devices such as glucose monitor, & insulin syringe aids,
are helpful for these patients.
Talking books, vocalization devices (computer system) are also
helpful.
Contact lenses to correct refractive errors is contraindicated because
of possible Corneal desenstivity & high risk of infections.

DESCRIPTION –
It is a bilateral, non inflammatory, progressive ectasia of the
cornea characterized by thinning & steepening of the
cornea.
The cone like protrusion produces progresdive decrease in
vision due to irregular myopic astigmatism.
ETIOLOGY –
An association with atopic disease has been observed,
leading to speculation that excessiveveye rubbingvcan
induce, accelerate the condition.
INCIDENCE –
In general population, b/w 1 & 600 per 100000.

VISUAL ACUITY –
VA ranges from normalbto markedly finished, depending on
the extent of the condition.
VISUAL FIELD –
No definitive VF defect, but distortion of field is noted.
Atopic dermatitis, vernal catarrh, asthma, hay fever.
Myopia with irregular astigmatism, thinning of the cornea.
Scissor reflex during retinoscopy and keratometric mires
Are apparent in early stage.

Vertical striae of the posterior stroma, fine Anterior stromal
scars, iron deposition around the base of the cone.
Munson‘s sign, a V shaped confirmation of the lower lid
producing by the bulging central cornea, in advanced
keratoconus.
Spectacle blurring, image distortion, starbursts around
objects, monocular diplopia, necessitating the use of RGP
contact lens.
Down syndrome, Marfan syndromE, osteogenesis
imperfecta.

ADJUNCT TESTING –
Keratometry, Placido disc & CCT are used to document
topographic changes.
Central/paracentral corneal steepening with irregular
astigmatic changes are common in keratoconus patients.
Penetrating keratoplasty is indicated when the pt is unable
to obtain clear, comfortable vision with CL or unable to
tolerate wearing a contact lens.
Lamellar keratoplasty & epikeratophakia are alteranative
procedures.

A careful refraction should be performed.
RGP CLs can provide a regular, to eliminate irregular
astigmatism.
Pinhole lenses, stenopeic slit & aperture contact lens may be
indicated to limit the refractive area of the cornea to prevent
ghost images.
CPFs , tints, sunlenses are helpful due to glare &
photophobia. Excessive light should be avoided.
CCTV for magnification of distance, intermediate and near.

DESCRIPTION –
It appears as a round red lesion in the fovea, usually from 1/3rd -
2/3rd of a disc diameter in size, with a gray halo of surrounding
(marginal) retinal detachment.
ETIOLOGY –
It may be caused by trauma, myopia, cystoid macular edema,
inflammation.
INCIDENCE –
Macular holes occurs more commonly in middle aged to elderly
women, unilateral more chances.
VISUAL ACUITY –
VA, 1 & 2 stage, range from 20/25-20/80.
VA, 3 & 4 stage, usually stabilizes at the 20/200 level.

VISUAL FIELD –
Full thickness holes result in dense Central scotonas.

Patients with macular holes report distortion or decressed
vision or both.
Vitrectomy, to relieve traction have shown favourable results
when treated early.
Refractive errors should be evaluated.
Magnification at near & distance with microscopes,
magnifiers & telescopic devices.
Eccentric viewing techniques & direct lighting in
conjunction with low vision devices may be beneficial.

DESCRIPTION –
It is an optic neuropathy caused by elevated IOP & reduced
blood flow to the optic nerve resulting in peripheral visual
field loss progressing to central vision loss when severe.
It is classified as open angle or angle closure glaucoma .
Developmental glaucoma is caused by maldevelopment of
the anterior segment.
ETIOLOGY –
Several risk factors, including, family history, advanced age,
systemic vascular disease.
Ocular risk factors include, blunt trauma, pigmentary
dispersion, pseudoexfoliation, rubeosus iridies, uveitis, use
of steroidal agents.

INCIDENCE –
Glaucoma is the second leading cause of blindness.
Approx. 1 of 50,older than the age of 40 yrs.
Approx. 1 million unaware that they have the condition.
VISUAL ACUITY –
Central VA is generally unaffected until the end stage of this
disease.
VUSUAL FIELD –
VF defects include paracentral scotonas, arcuate scotonas,
nasal steps, & temporal wedges.
Progressive VF loss from these areas occurs as the disease
worsens.

Increased IOP,optic cup enlargement,localised vertical notching,or
narrowing of the optic nerve head rim tissue,superficial splinter
hemorrage,loss of nerve fibre layer & asymmetric cupping.
Glaucoma patients with restricted fields report difficulty locating
objects,which affects basich functions such as orientation & mobility
& reading continuity.
ADJUNCTTESTING –
IOP measurements,gonioscopic examination of AC angle,
stereoscopic optic nerve evaluation,& thresholdVF assessment.
IOP above 21 mm Hg should be considered supicious for glaucoma.
Photodocunentationis helpful for monitoring progression of optic
nerve damage.
Computerizedoptic nerve analyzersprovide sensitive evaluation of
glaucomatousdamage by also measuring optic nerve head status in
terms of topography,& NFL thickness.

Medically lowering IOP with aqueous suppressants supplemented
by agents that enhance outflow.
Typically, laser trabeculoplasty, filtering surgery, or cycloablative
procedures may be required when medical theapy fails.
In angle closure glaucoma, to medically break the attack, perform
a peripheral iridectomy & protect the fellow eye.
These patients often are not reffered until the end stage of the
disease at which time they are experiencing both central VA &
peripheral field loss.
CCTV, are useful because they allow for increased contrast &
brightness along with magnification.

CPFs are beneficial in reducing glare & improving contrast for
patients with glaucoma.
Non optical devices should be explored.
Telescopes can be used to enhance the patient’s visual field.
Instruction in long cane travel can also be beneficial to patients
whose problem with orientation and mobility.
Use of flashlight can be helpful for night travel.
Support groups should be considered.
PROGNOSIS –
It can be controlled with medical treatment idmf diagnosed &
treated in a timely manner.
In pt.Who have IOP i.e. Poorly controlled, slowly progressive
vision loss may eventually result in total blindness.

DESCRIPTION –
It occurs when there is excessive stretching & expansion of the
posterior segment of the eye associated with increased axial
length.
Gradual degenerative changes occur as the Sclera, choroid &
retina becoms thinner.
ETIOLOGY –
It nay be geneticall inherited, but the mechanism of
transmission is poorly understood.
INCIDENCE –
It is approx. 2% & us tge 7 th leading cause of blindness.
VISUAL ACUITY –
VA may be correctable to 20/20 .

VISUAL FIELDS –
High degree of myopia can results in a variety of VF defects.
Central ring shaped scotoma, as well as hemianopic & quadratic
defects, can arise in the presence of posterior staphyloma.
Diffuse tessellation of the fundus can be seen due to thinning of the
pigmented epithelium.
Peripapillary scleral crescent results from failurevof the choroid &
RPE to extend to the disc margin.
Posterior staphyloma, represented as an outpouching of the post.
Eyewall.
Lacquer cracks, yellow- appearing linear breaks in Bruch’s
membrane, are axial length changes.
A round black lesion, k/as Fuch’s spot, is a result of hyperplasia of the

Peripheral retinal changes associated with thinning predispose
affected eyes to retinal detachment.
These pathologic changes in the fundus, refractive error of
greater than 6.00-8.00 D of myopia.
Down syndrome- chromosomal anomaly ie associated with
mental deficiency, small stature, high myopia, epicanthus,
telecanthus & esotropia.
Marfan’s syndrome- connective tissue disorder ie associated with
high myopia, keratoconus, subluxated lens, blue Sclera, & retinal
detachment, laxity of joints, sternal deformities.
Stickler’s syndrome- hereditary hyaloideo-retinopathy with
skeletal dysplasia, cleft palate, flattened facies, mental
retardation, high myopia, liquified vitreous, RPE changes, retinal
detachment.

ADJUNCT TESTING –
FA may be indicated if CNV is suspected.
In case if CNV, laser photocoagulation may be helpful.
Prophylactic treatment with cryopexy/ photocoagulation to
symptomatic, peripheral retinal breaks or tears may be
warrented in an effort to prevent retinal detachment.
Spectacles/ contact lens usually improves visual acuity.
Contact lens is better than spectacle lens.
Sun lenses, can eliminate photophobia & direct illumination at
near is helpful.
If night vision is poor, a flash light may be helpful.

DESCRIPTION –
It is an involuntary, rhythmic, to- fro oscillation of the eyes.
It is described by amplitude, frequency, & wave form.
If the eyes move with equal spoed in both durection, pendular
nystagmus & eyes moves faster in one direction, jerk
nystagmus.
ETIOLOGY –
Congenital nystagmus is present at birth & may be transmitted
as an X linked recessive or autosomal dominant trait.
VISUAL ACUITY –
It is variable among patients with congenital nystagmus.
VISUAL FIELD –
It is usually unaffected in patients with nystagmus.

Reduced visual acuity & nystagmus intensity decrease on
convergence & is absent during sleep.
When one eye is covered, the amplitude of nystagmus
increases.
Patients with congenital nystagmus do not experience
oscillopsia.
Correcting high Refractive error will sometimes reduce
nystagmus & improves acuity.
Magnification devices at distance & near are beneficial to
patients with congenital nystagmus.
PROGNOSIS –
It initially Presents itself at 3-6 months of age & persists in a

DESCRIPTION –
It can be classified into 3 categories, Heredodegenerative
optic atrophy should be considered when there is insidious,
bilateral loss of Central vision in childhood.
Prinary optic atrophy, cause damage to retinal ganglion cells
and secondar optic atrophy subsequent to disc edema.
ETIOLOGY –
Primary optic atrophy occurs after many conditions,
including inflammatory, infiltrative, toxic, ischemia, trauma,
demyelination.
These conditions are associated with loss of ganglion cells,
resulting optic nerve atrophy.
Secondary optic atrophy, causes papillitis & papilloedema
that disrupt the NFL.

VISUAL ACUITY –
VA ranges from 20/20 to hand motion.
VISUAL FIELD –
VF defects generally affect Central vision.
Paracentral, cecocentral or central scotonas may be present.
Decreased vision, diminished color perception, sluggish pupillary
response to light, photophobia, NFL thinning & possible nystagmus.
Magnification devices at both distance & near for patients with
decreased vision, & Excessive lighting should be avoided.
Sunlenses, tints, filters may help to eliminate glare, both indoors &
outdoors.

DESCRIPTION –
It results from accumulation of fluid b/w the sensory retina &
the RPE.
This fluid collection occurs in three ways.
A rhegmatogenous RD Results from a break in the retina,
allowing fluid to escape from the vitreous cavity into the
subretinal space.
Exudative RD occurs as a result of damage to the RPE/ retinal
blood vessels, allowing fluid to pass into the subretinal space.
Tractional RD results from vitreous membranes, caused by
penetrating injury or by proliferative retinopathy pulling the
neurosensory retina away from the pigment epithelium.

ETIOLOGY –
Rhegmatogenous RD can be precipitated by posterior vitreous
detachment, an atrophic hole, ab operculated tear.
Predisposing factors include blunt trauma, high myopia, aphakia,
lattice degeneration, choroidal coloboma.
Causes of exudative RD includes choroidal tumours,
chorioretinal inflammation, scleritis, retinal vascular disease
Tractionsl RD- diabetic retinopathy,eales disease, ROP.
VISUAL ACUITY –
It can be severely reduced if there is macular area involvement.
VISUAL FIELDS –
VF defects develop corresponding to the site of retinal
detachment.

Retinal tear, retinal break, floating spots, vitreous
detachment, vitreous hemorrhage,
ADJUNCT TESTING –
Diagnostic ultrasound is important.
Scleral buckling or pneunatic retinooexy are the most
common treatment for rhegmatogenous RD.
During scleral buckling surgery cryotherapy, diathermy or
photocoagulation is performed to create chorioretinal
adhesion at the site of the localised break.
Sub retinal fluid may be surgically drained.

Treatment of exudative RD, managing the underlying
etiology.
Treatment of tractional RD, involving the macula is pars
plans vitrectomy .
COFs, filters, tints can be eliminated glare or photophobia.
Direct illumination for seeing near tasks.
Magnification devices for distant and near may be helpful.
Non optical devices should also be demonstrated.
If bilateral temporal detachment occurs prisms may be
considered for improved mobility along with orientation.

RETINOPATHY OF
PREMATURITY
(ROP) –

DESCRIPTION –
ROP is an abnormal proliferation of the developing retinal
blood vessels in eyes of newborn infants in whom retinal
vascularization is incomplete.
It is commonly seen in low birth weight infants, premature
infants, & infants who received oxygen therapy .
ETIOLOGY –
During normal development,bthe retinal vasculature is built
from the optic nerve outward.
Exposure of immature peripheral retina to high levels of O2
results in failure of normal development of retinal vasculature.
This failure of vascularization, ischemia results, causing
neovascularization.

INCIDENCE –
Approx. 450-500 babies are blinded by ROP each yr.
VISUAL ACUITY –
VA ranges from 20/20 to no light perception, depending on
severity.
VISUAL FIELD –
VF defects are variable, most common nasally, correlating with
the area of non vascularized temporal periphery.
ROP is classified by severity, location & extent.
Severity-
Stage 1- appears as a sharp demarcation line b/w vascularized
& non vascularized retina.

Stage 2- formation of an elevated ridge at the site of the
demarcation line.
Stage 3- extraretinal fibrovascular proliferation tissue extending
from the ridge onto the vitreous from the surface of retina.
Stage 4- subtotal RD without foveal involvement or with foveal
involvement.
Stage 5- a total funnel shaped retinal detachment (RD).
Location –
Zone 1- Consists of a circle, the radius of which extends twice
the disc fovea distance in all directions from the disc.
Zone 2- extends from the edge of zone 1 out to the ora serrata
on the nasal side & slightly anterior to equator temporally.
Zone 3- a crescent that involves the remaining temporal, inferior
& superior retina.

Extent –
The extent of the condition is simply specified in terms of
the clock hours involved.
ASSOCIATED OCUKAR FINDINGS –
High myopia, microphthalmia, glaucoma, cataract,
leukocoria, uveitis, shallow anterior chamber,dragged
macula, retinal pigmentary changes, retinal folds,
amblyopia, anisometropia, strabismus, nystagmus and
retinal detachment, decreased visual acuity & photophobia.
If ROP develops, the pt should be followed more closely
according to the severity of the disease process.
Treatment with cryotherapy should be performed on atleast
one eye in pt.

Photocoagulation therapy for eyes with threshold disease
has been shown to result in outcomes similar to those found
after cryotherapy.
Treatment for stage 4 includes scleral buckling with
drainage of subretinal fluid.
Stage 5 ROP may require vitrectomy, lensectomy, &
membrane peeling to reattach the retina.
Pt with any stage of ROP should be monitored indefinitely
for development of retinal breaks.
Large dosages of vit E has been speculated to reduce the
severity of ROP .
This has not been proved, & complications from high dose
vit E can occur.

Firstly, myopic refractive error can be corrected with
Spectacle or contact lenses.
In spectacles with high prescription, ARC should be
considered.
Pt may also benefit from magnification with microscopes,
magnifiers, CCTV, Telescopic devices.
Various tints & filters may be useful in decreasing
photophobia.
Increased, direct, non glare illumination is helpful at near.
Mobility & orientation services, if their peripheral fields
have been affected.
PROGNOSIS –
Due to secondary complications of glaucoma, cataract, &

DESCRIPTION –
It us characterized by progressive visual field loss, night
blindness, adnormal ERG recording.
It is the most common of the hereditary retinal dystrophies.
ETIOLOGY –
Heredity is extremely important in RP.
Approx. 60-80%, pupolation affected by RP has inherited it
autosomal recessively. Autosomal dominant transfer is the
2nd most prevalent form. The X linked firm is the least
prevelent.
No family history of RP & males are commonly affected
than females.
Dominant inheritance is milder & later onset disease,
whereas X linked cases are more severe .

INCIDENCE –
The occurrence of RP varies b/w 1 in 2000 to 1 in 7000
population.
It is more common in males.
VISUAL ACUITY –
Central vision ranges from 20/20 to no light perception.
VISUAL FIELD –
VF loss begins in the midperiphery, extending inward &
outward, creating a donut shaped field defect.
Many patients are unaware of the field loss becoz it’s slow
progressive nature allows for long term adaptation.

Many fundus changes can occur with RP.
With loss of pigment, the RPE appears moth eaten .
With dispersion of pigment, the underlying choroidal
vasculature becomes prominent, giving the fundusva
tesellated appearance.
Optic nerve appears to have a waxy pallor. & drusen
formation & CD ration reduced.
Loss of Central visual acuity, cystoid macular edema (CME),
posterior subcapsular cataract, high amount of myopia,
astigmatism, nyctalopia & dark & Light adaptation speed
delay, color perception reduced & photophobia.

ADJUNCT TESTING –
ERG shows decreased A & B waves that eventually flatten
in late stages.
At this time, there is no treatment of RP.
Megadise of vit A palmitate may be some benefit in
showing progression of disease process.
▪CME, good response treatment with acetazolamide in
approx 50% patients.
Cataract surgery, when indicated, may be helpful.

Refractive error should be evaluated carefully.
Magnification can be provided at distance and near with low
vision device foemr pt with Central vision loss.
CCTV are useful becoz they allow for incresed contrast &
brightness along with magnification.
CPF lenses are helpful for reduce glare in pr with posterior
subcapsular cataract.
Non optical devices should be explored.
VF loss creates problems with orientation and mobility.
Instruction in long cane ttavek & use of a flashlight for night
travel.
Genetic counseling is necessary.

DESCRIPTION –
It is characterized by a vermillion fundusvcaused by
excessive lipofuscin storage with macular atrophy or flecks
at the level of the RPE in a typical distribution.
ETIOLOGY –
It is inherited autosomal recessively.
Clinical findings showing dominant inheritance.
VISUAL ACUITY –
Patients usually present with bilateral, decreased Central
vision in childhood or young adulthood.
Initially VA may be 20/20 level & by the second decade,VA
declines & stabilizes at the 20)200 level or slightly more.

VISUAL FIELD –
It can reveal a relative central scotoma, progressively to an
absolute scotoma.
Initially, the fundus may appear normal. Loss of foveal reflex
may be the only initial sign.
The fundus appearance of yellow flecks that have been
described as having a pisciforn (fishlike) shape, may be
confined to the macula, or may extend into the equator.
The degree & pattern of RPE atrophy may not correlate with
the degree of vision loss.
The RPE may be heavily pigmented from abnormal lipofuscin
storage, thereby obscuring the choroidal details.
Decreased vision, abnormal color vision, photophobia &

ADJUNCT TESTING –
FA shows prominent retinal vessels on a dark background of
the silent choroid.
Hyperfluorescence will occur in areas of RPE atrophy.
Full field ERG are typically normal, whereas foveal ERG are
abnormal.
A careful refraction should be rule out.
Eccentric viewing & magnification devices for near &
distance are beneficial for these patients.
Direct illumination may be very helpful for near tasks.
Filters & sunlenses can be reduced photophobia.
Non optical devices should be demonstrated.

DESCRIPTION –
It is the most common cause of chorioretinitis.
It is a parasitic disease caused by the organism toxoplasma
gondii.
ETIOLOGY –
Ocular toxoplasmosis is acquired most often congenitally from
exposure to the organism prenatally but may be acquired
through inhalation of oocytes from cat feces or ingestion of
contaminated meat.
T. Gondii is transmitted within the circulating leukocytes & has
a predilection vfor retina & CNS.
The organism multiplies within the infected host cells. If tge
cells bursts, the organism is liberated & inflammation occurs.
If hist cells does not burst, cysts may form with reactivation of

INCIDENCE –
It is estimated b/w 1 in 1000 & 1 in 10000 .
The incidence transplacental transmission, which the pregnent women
becomes infected.
VISUAL ACUITY –
VA can be severely reduced depending on the extent & involvement
of chorioretinitis in the macular area.
VISUAL FIELD –
VF defects are variable, depending on number, size, and location of
chorioretinal scars.
SYSTEMIC SIGN & SYMPTOMS –
In congenital,CNS disturbance such as convulsions & intracranial
calcifications.

In congenitally, Decreased acuity, & Strabismus & retinitis.
In acquired, blurred vision, floaters, lesions- appears white&
elevated.
Muktifocal, gray- white, punctate lesions at pigmented
epithelium.
Overlying vitreous haze occurs due to vitritis.
Iritis, arteritis, periphlebitis, OPTIC neuritis & papillitis may be
seen.
ADJUNCT TESTING –
The indirect fluorescent antibody test is helpful in the diagnosis
of congenital toxoplasmosis.
Enzyme linked immunosorbant assay defects IgG & IgM

A systemic corticosteroid & antitoxoplasmic agents is the
treatment of choice. Or cryotherapy & laser photocoagulation
have been used.
Sulfadiazine, pyrimethamine, tetracycline & clindamycin
commonly used.
The pt platelet count must be monitored closely if
pyrimethamine is used.
Refractive error should be carefully evaluated.
Magnification at both distance & near with optical devices .
Direct illumination is helpful for near tasks.
Absoptive lenses are helpful in reducing glare & photophobia.

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