CO Optical Instruments & Diagnostic Equipment Flashcards

The Frisby stereotest differs from polarized or anaglyphic stereotests because it:

Answer: Uses real depth without any glasses

The Frisby test presents real physical depth differences using transparent plates of different thicknesses, requiring no special glasses.

In the Maddox rod test, when the red streak passes through the white light source, this indicates:

Answer: Orthophoria — no deviation is present

When the streak passes through the light, the eyes are aligned (orthophoria) since no dissociated deviation exists.

Which instrument uses the principle of fogging one eye to measure the accommodative convergence to accommodation (AC/A) ratio?

Answer: Gradient method with trial lenses

The gradient AC/A method uses lenses (typically +1.00 or -1.00 D) to alter accommodation and measures the resultant change in alignment to calculate the ratio.

The Amsler grid is used to assess which visual function?

Answer: Central visual field and metamorphopsia

The Amsler grid detects scotomas and distortion (metamorphopsia) in the central 20 degrees of visual field, commonly used to monitor macular disease.

A slit lamp biomicroscope allows examination of the anterior segment using which illumination technique to assess corneal edema?

Answer: Specular reflection

Specular reflection from the corneal endothelium reveals cell density and morphology, and disturbance of this pattern indicates corneal edema.

The distance Randot stereotest measures stereoacuity at distance using which technology?

Answer: Polarized vectograph targets

The distance Randot uses polarized vectograph technology to present disparate images to each eye, testing stereopsis at 3 meters or 10 feet.