Amblyopia

Question 1

Definition of Amblyopia

Answer 1

refers to a unilateral or bilateral decrease in vision acuity caused by abnormal vision development in childhood or infancy, without identifiable pathology of the eye or visual pathway.

Question 2

Clinical Definition of Amblyopia

Answer 2

Difference of 2 or more lines on a Snellen chart in unilateral amblyopia.
Visual acuity of 6/12 or worse in bilateral amblyopia.

Question 3

Prevalence of Amblyopia

Answer 3

Worldwide prevalence: 2-5%.
WHO estimates 19 million children under 15 are visually impaired, with 12 million due to uncorrected refractive errors and amblyopia.
Leading cause of unilateral visual impairment in children/young adults (50-73%).

Question 4

Pathophysiology of Amblyopia

Answer 4

Critical period: Birth to 7-8 years.
Poor/mismatched visual information leads to brain suppression and disuse of the eye.
Lack of visual stimuli results in underdevelopment of the visual cortex.

Question 5

Causes of Amblyopia

Answer 5

Stimulus deprivation (e.g., ptosis, cataract, occlusion).
Strabismus.
Significant refractive error.
Visual cortical cells losing the ability to respond to stimulation

Question 5

Strabismic Amblyopia

Answer 5

Poor alignment of the eyes, leading to blurred images.
Brain suppresses the image from the misaligned eye to avoid double vision.

Question 6

risk Factors for Amblyopia

Answer 6

Family history of strabismus or amblyopia.
Premature birth.
Low birth weight.
Developmental delays with increasing age.

Question 7

Types of Amblyopia

Answer 7

Strabismic Amblyopia
Refractive Amblyopia
Anisometropic Amblyopia
Isoametropic Amblyopia
Meridional Amblyopia
Visual (Sensory) Deprivation Amblyopia
Organic Amblyopia
Reverse Amblyopia
Idiopathic Amblyopia

Question 8

Refractive Amblyopia

Answer 8

Anisometropic: Different refractive errors in each eye cause the brain to suppress the less clear image.
Isoametropic: Bilateral visual acuity decrease from large, approximately equal uncorrected refractive errors in both eyes.
Meridional: From uncorrected bilateral astigmatism in early childhood

Question 9

Organic Amblyopia

Answer 9

Subtle sub-ophthalmoscopic retinal damage without gross detectable anomalies.

Question 10

Visual Deprivation Amblyopia

Answer 10

Caused by eye abnormalities obstructing the visual axis.
Examples: Cataracts, unilateral complete ptosis, vitreous hemorrhage, corneal opacities.

Question 11

Reverse Amblyopia

Answer 11

Visual deprivation in the fellow eye due to patching.

Question 12

Suspecting Amblyopia

Answer 12

Decreased visual acuity not improving with correction.
Decreased contrast sensitivity.
Poor hand-eye coordination.
Depth perception issues.
Blurred vision.

Question 13

Investigations for Amblyopia

Answer 13

Comprehensive history and eye examination.
Inquiry about difficulty in viewing, head tilting, and eye drifting/wandering.
Visual assessment for differences between eyes or impaired vision.

Question 14

Management of Amblyopia

Answer 14

Eliminate obstacles to vision.
Correct refractive errors.
Force use of the poorer eye by limiting the use of the better eye during the sensitive period of visual development.

Question 15

Management Techniques

Answer 15

Optical correction with spectacles.
Patching: Covering the good eye to develop vision in the amblyotic eye.
Atropine penalization: Using cycloplegic drops to degrade the vision of the better eye.
Surgery for cataracts or strabismus

Question 16

Prognosis of Amblyopia

Answer 16

Generally good if treatment starts before age five. Prognosis worsens with age, with potential for total vision loss in the affected eye.