1Mar
Worth 4-Dot Test . Binocular Vision . About Fusion .Dr Rakib Hasan .

Fusion in vision refers to the brain’s ability to combine the images from both eyes into a single, clear, and three-dimensional image. It involves both motor fusion (eye alignment) and sensory fusion (perception of a single image). To check for fusion, several clinical tests are used:

 

Worth 4-Dot Test

Purpose: Assesses the presence of suppression and fusion.

Procedure:

The patient wears red-green glasses (red over the right eye, green over the left).

They look at a Worth 4-dot flashlight or wall-mounted target.

Results:

4 dots seen → Normal fusion

2 red dots (OD suppression) or 3 green dots (OS suppression) → Suppression

5 dots seen → Diplopia (no fusion)

  1. Bagolini Striated Glasses Test

Purpose: Evaluates sensory fusion in natural viewing conditions.

Procedure:

The patient wears Bagolini lenses and looks at a point light source.

Each eye sees a streak of light at 45° and 135°, forming an “X” if fusion is present.

Results:

Continuous X → Normal fusion

One missing line → Suppression

Two separate streaks → Diplopia

 

Stereopsis Tests (Depth Perception Tests)

 

Purpose: Indirectly assess fusion by checking if the patient has binocular depth perception.

Common Tests:

Titmus Fly Test: The patient wears polarized glasses and identifies depth in stereoscopic images.

Randot Stereo Test: Checks fine stereopsis using random-dot patterns.

TNO Test: Uses red-green anaglyphs to test for stereopsis and suppression.

Maddox Rod Test (for Motor Fusion)

 

 

Purpose: Assesses alignment and fusion ability.

Procedure:

A Maddox rod is placed over one eye while the patient looks at a light source.

The patient describes the relative position of the light streak and the actual light source.

Helps detect heterophoria or heterotropia, which can impact fusion.

 

Prism Fusion Range (Motor Fusion Test)

 

Purpose: Evaluates the range of fusional vergence (how much prism the patient can handle before diplopia).

Procedure:

Base-in and base-out prisms are introduced while the patient fixates on a target.

The prism is increased until fusion is lost.

Results:

Low fusional reserves may indicate convergence or divergence insufficiency.

Dr Rakib Hasan

M.Optom 

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Vision Therapy In Kolkata
12Feb
Vision Therapy In Kolkata | Strabismic amblyopia |Amblyopia vision Therapy In Kolkata

Dr Rakib Hasan ,M.Optom

Strabismic amblyopia, also known as strabismus-related amblyopia, is a type of lazy eye (amblyopia) caused by strabismus, a misalignment of the eyes.

Causes

  1. Strabismus: Misalignment of the eyes, causing the brain to favor one eye over the other.
  2. Esotropia: Crossed eyes, where one eye turns inward.
  3. Exotropia: Wall-eyed, where one eye turns outward.
  4. Hypertropia: Vertical misalignment, where one eye is higher than the other.

Symptoms

  1. Blurred vision: Reduced vision in the affected eye.
  2. Double vision: Seeing two images of a single object.
  3. Eye strain: Fatigue, headaches, or discomfort when using the affected eye.
  4. Depth perception difficulties: Trouble judging distances or spatial relationships.

Diagnosis

  1. Comprehensive eye exam: Assessing visual acuity, refraction, and eye alignment.
  2. Cover test: Evaluating eye alignment and movement.
  3. Retinoscopy: Measuring the reflection of light in the eyes.

Treatment

  1. Glasses or contact lenses: Correcting refractive errors and improving eye alignment.
  2. Patch therapy: Covering the stronger eye to strengthen the weaker eye.
  3. Atropine therapy: Dilating the stronger eye to reduce its dominance.
  4. Surgery: Correcting eye misalignment or removing cataracts (if present).
  5. Vision therapy: Customized exercises to improve eye coordination, depth perception, and visual processing.
Dr Rakib Hasan

Prognosis

Early detection and treatment can significantly improve visual outcomes. However, if left untreated, strabismic amblyopia can lead to permanent vision loss in the affected eye.

Complications

  1. Permanent vision loss: If left untreated, amblyopia can lead to irreversible vision loss.
  2. Depth perception difficulties: Untreated amblyopia can cause lifelong difficulties with depth perception.
  3. Social and emotional impacts: Untreated amblyopia can affect self-esteem, social interactions, and overall quality of life.

Regular eye exams and prompt treatment can help prevent these complications and ensure optimal visual development.

Vision Therapy In Kolkata

Vision Therapy In Kolkata | Strabismic amblyopia | Amblyopia vision Therapy In Kolkata


Address: 2nd floor, 1/13, Dover Terrace, opp. Dr Nihar Munsi Eye Foundation, Dover Terrace, Ballygunge, Kolkata, West Bengal 700019