Eagleview Eye Clinic

Archives October 2025

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.

MADDOX ROD

The Maddox rod is a cylindrical lens with parallel rods that convert a point source of light into a streak or line. It’s used in ophthalmology and optometry to assess and measure strabismus (misaligned eyes) and heterophoria (latent strabismus).

How it works:

  1. Light source: A point source of light is shone through the Maddox rod.
  2. Streak formation: The rods convert the light into a streak or line, which is perceived by the patient.
  3. Alignment assessment: The orientation and position of the streak relative to the other eye help diagnose and quantify deviations in eye alignment.

Types of Maddox rods:

  1. Single Maddox rod: Used to assess horizontal or vertical deviations.
  2. Double Maddox rod: Used to assess torsional deviations.

Clinical applications:

  1. Strabismus diagnosis: Helps diagnose and quantify esotropia, exotropia, hypertropia, and other types of strabismus.
  2. Heterophoria diagnosis: Detects latent strabismus, which can cause eye strain or other symptoms.
  3. Treatment planning: Guides treatment decisions, such as prism correction or strabismus surgery.

The Maddox rod is a valuable tool in ophthalmology and optometry, enabling practitioners to accurately diagnose and manage strabismus and heterophoria.

WORTH 4 DOT TEST

The Worth 4-Dot test is a clinical test used in ophthalmology and orthoptics to assess binocular vision and detect suppression or anomalies in binocular vision.

Key Features:

  1. Four dots: The test involves four dots or lights, typically arranged in a square or diamond pattern.
  2. Color filters: The patient wears red-green glasses or filters, with one eye seeing two dots (or lights) and the other eye seeing the other two.
  3. Binocular fusion: The test assesses the patient’s ability to fuse the images from both eyes.

Purpose:

The Worth 4-Dot test is used to:

  1. Assess binocular vision: Evaluate the patient’s ability to combine images from both eyes.
  2. Detect suppression: Identify suppression or anomalies in binocular vision, which can indicate conditions like strabismus or amblyopia.
  3. Monitor treatment: Track changes in binocular vision during treatment or therapy.

How it works:

  1. Patient views the dots: The patient looks at the four dots or lights through the red-green glasses.
  2. Response evaluation: The practitioner evaluates the patient’s response, noting whether they see four dots (indicating binocular fusion), two dots (indicating suppression), or some other pattern.

The Worth 4-Dot test provides valuable information about binocular vision and can help diagnose and manage various vision disorders.

AMSLER’S GRID

An Amsler grid is a square-shaped grid with evenly spaced horizontal and vertical lines, used to detect vision problems related to the macula, particularly in conditions like age-related macular degeneration (AMD).

Key Features:

  1. Square grid: The grid consists of evenly spaced horizontal and vertical lines, forming small squares.
  2. Central dot: A small dot is typically placed at the center of the grid, which serves as a fixation point.
  3. Symmetrical pattern: The grid’s symmetrical pattern helps identify distortions or irregularities in vision.

Purpose:

The Amsler grid is used to:

  1. Detect macular problems: Identify distortions or blind spots in the central visual field, which can be indicative of macular degeneration or other conditions.
  2. Monitor vision changes: Track changes in vision over time, allowing for early detection of potential issues.
  3. Self-monitoring: Patients can use the Amsler grid at home to monitor their vision and report any changes to their healthcare provider.

How to use:

  1. Look at the grid: View the grid with one eye covered, focusing on the central dot.
  2. Check for distortions: Note any distortions, wavy lines, or missing areas in the grid.
  3. Repeat with the other eye: Cover the first eye and repeat the process with the second eye.

The Amsler grid is a valuable tool for detecting and monitoring macular problems, enabling early intervention and treatment.

ASTIGMATIC FAN DIAL

An astigmatic fan dial, also known as a fan dial or astigmatic dial, is a tool used in ophthalmology and optometry for detecting and measuring astigmatism. Here’s a more detailed description:

Key Features:

  1. Radial lines: The dial consists of multiple radial lines, often in a fan-like or dial shape, with lines spaced at regular intervals (usually 10-15 degrees).
  2. Rotating dial: The dial can be rotated to different positions, allowing the practitioner to determine the axis of astigmatism.
  3. Measurement markings: The dial typically has measurement markings or degree indicators to record the axis of astigmatism.

How it works:

  1. Patient views the dial: The patient views the fan dial through a phoropter or trial frame, often with corrective lenses in place.
  2. Determine astigmatism axis: The practitioner rotates the dial while asking the patient to identify the orientation of the lines that appear clearest or most distinct.
  3. Measure astigmatism: By determining the axis of the clearest lines, the practitioner can estimate the axis of astigmatism and prescribe corrective lenses accordingly.

Purpose:

The astigmatic fan dial is used to:

  1. Detect astigmatism: Identify the presence and amount of astigmatism in a patient’s eye.
  2. Measure astigmatism: Determine the axis and amount of astigmatism to prescribe corrective lenses.
  3. Refine prescriptions: Fine-tune prescriptions for patients with astigmatism.

The astigmatic fan dial is a useful tool in ophthalmology and optometry for diagnosing and correcting astigmatism, helping practitioners provide accurate and effective treatment.

ASTIGMATIC FAN DIAL

An astigmatic fan dial, also known as a fan dial or astigmatic dial, is a tool used in ophthalmology and optometry for detecting and measuring astigmatism. Here’s a more detailed description:

Key Features:

  1. Radial lines: The dial consists of multiple radial lines, often in a fan-like or dial shape, with lines spaced at regular intervals (usually 10-15 degrees).
  2. Rotating dial: The dial can be rotated to different positions, allowing the practitioner to determine the axis of astigmatism.
  3. Measurement markings: The dial typically has measurement markings or degree indicators to record the axis of astigmatism.

How it works:

  1. Patient views the dial: The patient views the fan dial through a phoropter or trial frame, often with corrective lenses in place.
  2. Determine astigmatism axis: The practitioner rotates the dial while asking the patient to identify the orientation of the lines that appear clearest or most distinct.
  3. Measure astigmatism: By determining the axis of the clearest lines, the practitioner can estimate the axis of astigmatism and prescribe corrective lenses accordingly.

Purpose:

The astigmatic fan dial is used to:

  1. Detect astigmatism: Identify the presence and amount of astigmatism in a patient’s eye.
  2. Measure astigmatism: Determine the axis and amount of astigmatism to prescribe corrective lenses.
  3. Refine prescriptions: Fine-tune prescriptions for patients with astigmatism.

The astigmatic fan dial is a useful tool in ophthalmology and optometry for diagnosing and correcting astigmatism, helping practitioners provide accurate and effective treatment.

CONTRAST SENSITIVITY

Contrast sensitivity refers to the ability to detect differences in luminance or color between objects and their background. It’s a crucial aspect of visual perception, enabling us to:

  • Distinguish objects: Contrast sensitivity helps us identify objects, textures, and patterns.
  • Navigate environments: It’s essential for tasks like driving, walking, or reading.
  • Perform daily activities: Contrast sensitivity affects our ability to perform tasks that require visual detail.

Factors Affecting Contrast Sensitivity:

  • Age: Contrast sensitivity can decline with age.
  • Eye conditions: Conditions like cataracts, glaucoma, or macular degeneration can affect contrast sensitivity.
  • Neurological disorders: Certain conditions, such as multiple sclerosis or stroke, can impact contrast sensitivity.

Testing Contrast Sensitivity:

  • Pelli-Robson chart: A standardized chart used to measure contrast sensitivity.
  • Functional Acuity Contrast Test (FACT): A test that assesses contrast sensitivity at different spatial frequencies.

Improving Contrast Sensitivity:

  • Correcting underlying conditions: Treating eye conditions or updating prescriptions can help improve contrast sensitivity.
  • Visual training: Certain visual training programs can help improve contrast sensitivity in some individuals.

By understanding contrast sensitivity, we can better appreciate the complexities of visual perception and take steps to maintain healthy vision.

PELLI ROBSON CONTRAST SENSITIVITY CHART

The Pelli-Robson contrast sensitivity chart is a tool used to measure an individual’s ability to detect differences in contrast, which is essential for everyday activities like reading and driving. Here’s how it works:

Key Features:

  • Contrast Sensitivity Measurement: The chart consists of rows of letters with decreasing contrast, allowing practitioners to assess the patient’s ability to detect subtle differences in contrast.
  • Standardized Design: The chart is designed to provide a reliable and repeatable measure of contrast sensitivity.

Clinical Applications:

  • Detecting Visual Impairments: The Pelli-Robson chart can help identify visual impairments, such as cataracts, glaucoma, or age-related macular degeneration, which can affect contrast sensitivity.
  • Monitoring Treatment: It can be used to monitor the effectiveness of treatments or interventions aimed at improving contrast sensitivity.

The Pelli-Robson chart is a valuable tool for eye care professionals to assess and monitor patients’ contrast sensitivity, helping to identify potential issues and develop effective treatment plans.

DUO CHROME TEST

The duochrome test is a subjective refraction technique used in ophthalmology and optometry to refine the spherical endpoint of a patient’s prescription. It works by utilizing the principle of chromatic aberration, where different colors of light are refracted differently by the eye’s optics.

How it works:

  1. Red and Green Filters: The test involves presenting the patient with two colors, typically red and green, which are focused at slightly different points due to chromatic aberration.
  2. Comparing Clarity: The patient is asked to compare the clarity of letters or symbols on both the red and green backgrounds.
  3. Adjusting the Prescription: Based on the patient’s responses, the practitioner adjusts the spherical power to achieve equal clarity between the two colors.

Purpose:

  • Refine Spherical Correction: The duochrome test helps fine-tune the spherical component of a prescription, ensuring the most accurate correction for nearsightedness or farsightedness.
  • Confirm Endpoint: It can confirm the endpoint of a subjective refraction, providing additional assurance in the final prescription.

The duochrome test is a valuable tool in clinical practice, particularly for patients with high visual demands or those requiring precise corrections.

TRIAL LENS SET

A trial lens set is a collection of lenses used to determine the correct prescription for eyeglasses or contact lenses. These sets typically include a variety of lenses with different powers and types, such as spherical, cylindrical, and prismatic lenses.

Types of Trial Lens Sets:

  • Full-aperture trial lens sets: These sets have lenses with full apertures, allowing for unobstructed vision during exams. They often come in metal or plastic rims and may include accessory lenses.
  • Compact trial lens sets: These sets are designed to be more portable and space-efficient, making them ideal for mobile practitioners or small clinics ¹ ².

Features to Consider:

  • Lens material: Glass or high-quality plastic lenses ensure accurate and reliable results.
  • Rim material: Metal rims are durable, while plastic rims are lighter and more resistant to corrosion.
  • Number of lenses: Sets can range from a few dozen to several hundred lenses, depending on the intended use and practitioner preference.
  • Accessory lenses: Some sets include additional lenses, such as prism lenses, Maddox lenses, or occluders, to facilitate more comprehensive eye exams ¹ ² ³.

Popular Brands:

  • Veatch Ophthalmic Instruments: Known for their high-quality, full-aperture trial lens sets with metal rims.
  • Rexxam: Offers trial lens sets with plastic or metal rims, along with robust trial frames.
  • UCanSee: Provides affordable trial lens sets with high-quality lenses and durable cases.
  • Keeler: A well-established brand in the ophthalmic industry, offering trial lens sets and frames