AMBLYOPIA(LAZY EYE)
PRESENTED BY
MADINA KHATUN(B.OPTOM)
INTRODUCTION:
Amblyopia is defined as the reduction of best corrected visual acuity in one
or both eyes caused by abnormal binocular interaction , (abnormal
development of visual pathway) during the critical period of visual
development that cannot be attributed to any ocular or visual system
abnormality or to refractive error.
It is usually unilateral, but it can be bilateral
It develops when there's a breakdown in how the brain and the eye work
together, and the brain can't recognize the sight from 1 eye.
Amblyopia is a common problem in babies and young children(birth to 7
-8years).
VISUAL PATHWAY
ETIOLOGY & EPIDEMIOLOGY:
A. STRABISMIC AMBLYOPIA(50%):Amblyopia results from
abnormal binocular interaction where there is continued
monocular suppression of the deviating eye.
B. REFRACTIVE AMBLYOPIA(15-20%)
ANISOMETROPIC : Amblyopia is caused by a difference in
refractive error between the eyes and may result from a
difference of as little as 1 dioptre(for uncorrected astigmatism
usually>1D). The more ametropic eye receives a blurred image,
in a mild form of visual deprivation. It is frequently associated
with microstrabismus and may coexist with strabismic
amblyopia.
BILATERAL AMETROPIC: Amblyopia results from high
symmetrical refractive errors, usually hypermetropia.
C. VISUAL DEPRIVATION (<5%):
Amblyopia results from vision deprivation. It may be unilateral or
bilateral and is typically caused by opacities in the media or
ptosis that covers the pupil.
Ptosis.
Corneal scar
Cataract etc.
AMBLYOPIC VISION:
CROWDING PHENOMENON: Patient with amblyopia have better visual
acuity(1 or 2 line better) reading single optotype than reading multiple
optotype in a row.
NEUTRAL DENSITY FILTER Rduce the overall luminance without inducing
a color change. Decreased luminance of the visual target results in
diminished central acuity in normal eyes. Decreased illumination of
visual targets has less of an effect on amblyopic eye because they are
not using central acuity.
ECCENTRIC FIXATION: All amblyopes have some degree of extrafoveal
fixation. Mild amblyopes(6/12 to 6/36) fixate so close to the fovea that
they appear to fixate centrally. Severe amblyopes(6/60 to CF) use a large
parafoveal area for viewing . This area of eccentric fixation is not a
pinpoint location but a general area of viewing.
SYMPTOMS:
Poor depth perception.
Squinting or shutting one eye.
Favoring one eye over the other.
Poor academic performance due to visual difficulties.
DIAGNOSIS:
Taking birth history, ocular history, family history, ocular motility
assessment , pupil examination, red reflex examination of
patients.
VISUAL ACUITY TEST: Preferred visual acuity testing according
to the age.(photoscreen or Snellen’s chart).
REFRACTION: Cycloplegic refraction for total refractive error.
OCULAR ALIGNMENT TEST: Cover uncover test for strabismus
detection.
BINOCULAR FUNCTION TESTS: Assessing stereopsis and other
binocular functions.
DIAGNOSIS:
TREATMENT:
CLEAR RETINAL IMAGE: Patient should receive full recfractive
correction to provide a clear retinal image.
CORRECT OCULAR DOMINANCE:
1. OCCLUSION THERAPY: Patching the dominant eye to
force the use of the amblyopic eye.
2.PENALIZATION: Applied to the dominant eye to blur
vision, encouraging the use of the amblyopic eye.
TREATMENT:
SURGICAL INTERVENTIONS: In cases of strabismus or cataracts,
surgery may be necessary to align the eyes or remove opacities.
VISION THERAPY: Vision therapy is a program that aims to improve a
person's visual abilities by using variety of ways such as- eye exercise ,
testing, occlusion .
PROGNOSIS:
Early detection and treatment are critical to improving
outcomes.
Prognosis is generally good if amblyopia is diagnosed and
treated early, typically before the age of 7-8, when the visual
system is most plastic.
Delayed treatment can result in permanent visual impairment.
REFERENCES :
Kanski’s Clinical Ophthalmology -John F. Salmon
Handbook of Pediatric Strabismus and Amblyopia- Kenneth W.
Wright , Peter H Speigel,Lisa S Thompson(editors).
Google sites
ChatGPT.
THANK
YOU….
