Amblyopia (Lazy Eye)

Understanding Amblyopia (Lazy Eye): Causes, Symptoms, and Treatment

Amblyopia, commonly known as lazy eye, is a condition characterized by reduced visual acuity in one or both eyes due to abnormal visual development during childhood. It occurs when the brain fails to process input from the affected eye.

Types of Amblyopia

1. Strabismic Amblyopia: Caused by suppression of the deviated eye in strabismus.

2. Refractive Amblyopia: Due to uncorrected refractive errors (especially anisometropia).

3. Deprivation Amblyopia: Caused by conditions that obstruct visual input (e.g., cataracts, ptosis).

4. Meridional Amblyopia: Associated with uncorrected astigmatism.

Pathophysiology

During the critical period of visual development (birth to 8 years), visual stimuli are necessary for proper maturation of the visual cortex. If one eye provides blurred or misaligned input, the brain suppresses that eye’s signal, leading to amblyopia.

Clinical Features

- Poor visual acuity in the affected eye

- Suppression of visual input from the amblyopic eye

- Lack of binocular vision

- Poor depth perception

Diagnosis

1. Visual Acuity Testing: Snellen chart or age-appropriate tests (e.g., Lea symbols).

2. Ocular Examination: Rule out structural abnormalities.

3. Cycloplegic Refraction: Identify refractive errors.

4. Binocular Vision Testing: Worth 4-dot test, stereopsis tests.

Management of Amblyopia

1. Treat the Underlying Cause: Correct refractive errors with glasses, remove cataracts or treat ptosis.

2. Occlusion Therapy (Patch Therapy): Cover the dominant eye to force use of the amblyopic eye.

3. Atropine Penalization: Atropine drops in the good eye to blur vision and encourage use of the amblyopic eye.

4. Vision Therapy: Exercises to improve visual function.

5. Monitoring: Regular follow-up to assess visual acuity improvement.