COT Optometry 3

Question 1

A patient wearing +2.50 D lenses moves a held object away and the image appears to move in the same direction. This is called:

Accepted Answer

With motion

Answer

Plus lenses act as converging lenses and produce 'with' apparent motion when the object is beyond the focal point.

Question 2

What does the vertex distance affect most significantly in high-powered prescriptions?

Accepted Answer

Effective power of the lens

Answer

Vertex distance changes the effective power of a lens; this effect is clinically significant for prescriptions exceeding ±4.00 D.

Question 3

Which refractive surgery procedure reshapes the cornea using a microkeratome or laser to create a flap before ablation?

Accepted Answer

LASIK

Answer

LASIK (Laser-Assisted In Situ Keratomileusis) involves creating a corneal flap before excimer laser ablation of the stromal bed.

Question 4

A patient with 20/200 best-corrected visual acuity in the better eye meets the definition of legal blindness in the US. What is the other criterion for legal blindness?

Accepted Answer

Visual field less than 20 degrees

Answer

Legal blindness is defined as best-corrected VA of 20/200 or worse, OR a visual field of 20 degrees or less in the better eye.

Question 5

Induced prism from decentered lenses can be calculated using Prentice's Rule. What is the induced prism for a -4.00 D lens decentered 5 mm?

Accepted Answer

2.0 prism diopters

Answer

Prentice's Rule: prism (Δ) = diopters × decentration (cm) = 4.00 × 0.5 = 2.0 prism diopters.

COT - Certified Ophthalmic Technician Practice Test

COT - Certified Ophthalmic Technician Practice Test

COT Optometry 3