Eagleview Eye Clinic

Tag eye health

MACULA

The macula is a specialized region at the back of the eye, responsible for central vision and fine detail.

Key functions:

  1. Central vision
  2. Color vision
  3. Fine detail vision

Location:

The macula is located at the center of the retina, including the fovea.

FOVEA CENTRALIS

The fovea centralis is a small pit in the macula of the retina, responsible for sharp central vision.

Key functions:

  1. High-acuity vision
  2. Color vision
  3. Central vision

Importance:

The fovea is crucial for tasks like reading, driving, and recognizing faces.

SEGMENT HEIGHT

Segment height refers to the vertical measurement of a bifocal or progressive lens segment.

What it’s for:

Segment height is used to:

  1. Position the lens segment correctly
  2. Ensure optimal vision through the segment

Measurement:

Segment height is typically measured from the lower eyelid margin to the top of the segment.

Krimsky test

The Krimsky test is used to measure strabismus (misaligned eyes) in patients who can’t fixate or have poor fixation.

What it’s for:

The Krimsky test is used to:

  1. Measure strabismus in patients with poor fixation
  2. Assess ocular alignment

How it’s done:

  1. A light is shone into the patient’s eyes.
  2. Prisms are placed in front of the deviated eye.
  3. The prism is adjusted until the corneal reflections are symmetrical.

What it shows:

The test measures the amount of strabismus, helping diagnose and manage eye alignment issues.

VAN HERRICK TEST

The Van Herrick test is a method used to estimate the depth of the anterior chamber angle in the eye.

What it’s for:

The Van Herrick test is used to:

  1. Assess the risk of angle-closure glaucoma
  2. Evaluate the anterior chamber angle width

How it’s done:

  1. A narrow slit beam is shone onto the peripheral cornea.
  2. The examiner observes the angle between the cornea and iris.
  3. The width of the angle is estimated and graded.

Grading:

The Van Herrick test grades the angle as:

  1. Grade 4: Wide open angle
  2. Grade 3: Moderate angle
  3. Grade 2: Narrow angle
  4. Grade 1: Extremely narrow angle
  5. Grade 0: Closed angle

What it shows:

The test helps identify patients at risk of angle-closure glaucoma, allowing for further evaluation and treatment if necessary.

HORIZONTAL COINCIDENCE TEST

The horizontal coincidence test, also known as the cover-uncover test or Hirschberg’s test, assesses binocular alignment and detects strabismus (misaligned eyes).

How it’s done:

  1. Patient fixates: The patient looks at a target, usually a light or object.
  2. Covering one eye: One eye is covered, and the movement of the uncovered eye is observed.
  3. Uncovering the eye: The covered eye is uncovered, and the movement of both eyes is observed.

Purpose:

The test helps detect:

  1. Strabismus: Misalignment of the eyes (esotropia, exotropia, hypertropia, etc.).
  2. Binocular vision problems: Issues with how the eyes work together.

The test provides valuable information about binocular alignment and helps diagnose and manage strabismus and other binocular vision problems.

THE BJERRUM TANGENT SCREEN

The Bjerrum tangent screen is a device used in ophthalmology to assess the visual field, particularly the central and paracentral areas. It’s a flat surface with a tangent curve marked on it, used to map out the field of vision.

How it’s used:

  1. Patient fixation: The patient fixates on a central point.
  2. Stimulus presentation: A stimulus (e.g., a small object or light) is moved along the tangent screen.
  3. Visual field mapping: The patient indicates when they see the stimulus, allowing the examiner to map out the visual field.

Purpose:

The Bjerrum tangent screen is used to:

  1. Detect visual field defects: Identify defects in the central and paracentral visual field.
  2. Monitor glaucoma: Track changes in the visual field associated with glaucoma.
  3. Assess optic nerve function: Evaluate the function of the optic nerve.

The Bjerrum tangent screen is a useful tool for assessing and monitoring visual field defects, particularly in glaucoma patients.

FARNSWORTH D15 TEST

The Farnsworth D15 test is a color vision test used to assess color perception and detect color vision deficiencies. Here’s a detailed overview:

Test Procedure:

  1. Colored caps: The test consists of 15 colored caps, each with a specific hue.
  2. Arranging the caps: The patient is asked to arrange the caps in a specific order, typically in a hue sequence.
  3. Testing conditions: The test is usually administered in a well-lit room with good color rendering.

Purpose:

The Farnsworth D15 test is used to:

  1. Detect color vision deficiencies: Identify individuals with color vision problems, particularly in the blue-yellow axis.
  2. Assess color discrimination: Evaluate the patient’s ability to distinguish between different colors.
  3. Monitor color vision: Track changes in color vision over time or after treatment.

Scoring and Interpretation:

  1. Error score: The number and type of errors are recorded and scored.
  2. Color confusion index: The results are often presented as a color confusion index, which indicates the severity of color vision deficiency.
  3. Interpretation: The results help diagnose and classify color vision deficiencies, such as tritanopia (blue-yellow deficiency).

Applications:

  1. Occupational vision assessments: Used in industries where color vision is critical, such as aviation, transportation, or graphic design.
  2. Clinical assessments: Helps diagnose and manage color vision problems in patients.
  3. Research: Used in studies on color vision and its applications.

The Farnsworth D15 test is a valuable tool for assessing color vision and detecting color vision deficiencies, enabling targeted interventions and accommodations.

TITMUS FLY TEST

The Titmus fly test, also known as the Titmus stereo test or Titmus test, is a widely used assessment tool for evaluating stereopsis, which is the ability to perceive depth and 3D vision.

How it works:

  1. Polarized glasses: The patient wears polarized glasses.
  2. Image presentation: The patient views a series of images, including a fly or other objects, through the polarized glasses.
  3. Depth perception: The images are designed to create a sense of depth, and the patient is asked to identify the objects or shapes that appear to be raised or recessed.

Purpose:

The Titmus test is used to:

  1. Assess stereopsis: Evaluate the patient’s ability to perceive depth and 3D vision.
  2. Detect binocular vision problems: Identify issues with binocular vision, such as strabismus or amblyopia.
  3. Monitor treatment progress: Track changes in stereopsis during treatment or therapy.

Common applications:

  1. Pediatric vision screening: Often used in children’s vision screenings to assess depth perception.
  2. Vision therapy: Used to evaluate and improve binocular vision and stereopsis.
  3. Occupational vision assessments: May be used in certain occupations that require depth perception.

The Titmus fly test is a valuable tool for assessing stereopsis and binocular vision, helping practitioners diagnose and manage vision problems.

MADDOX WING TEST

The Maddox wing test is a subjective test used in ophthalmology and orthoptics to measure heterophoria (latent strabismus) and assess binocular vision. It involves a device with two wings or handles that are adjusted to align two arrows or lines.

How it works:

  1. Patient views the arrows: The patient looks through the device and sees two arrows or lines, one with each eye.
  2. Adjusting the wings: The patient adjusts the wings until the arrows or lines appear aligned.
  3. Measuring deviation: The amount of deviation is measured from the scale on the device.

Purpose:

The Maddox wing test is used to:

  1. Measure heterophoria: Quantify the amount of latent strabismus.
  2. Assess binocular vision: Evaluate the patient’s ability to fuse images from both eyes.
  3. Diagnose and manage: Help diagnose and manage conditions like esophoria, exophoria, and hyperphoria.

The Maddox wing test provides a subjective measurement of heterophoria, allowing practitioners to plan treatment and monitor progress.