COT - Certified Ophthalmic Technician Contact Lens Principles Questions and Answers

Question 1

A technician evaluating a rigid gas-permeable (RGP) lens with fluorescein observes a dark, central area of bearing on the cornea, surrounded by a bright green ring of pooling in the mid-periphery.
What does this pattern indicate?

Accepted Answer

A flat fit (apical bearing)

Answer

A steep fit (apical clearance)

Answer

An ideal alignment fit

Answer

Excessive peripheral clearance

Question 2

The term 'Dk/t' is a critical parameter for contact lens materials. What does this value represent?

Accepted Answer

The oxygen transmissibility of the lens

Answer

The lens's resistance to protein deposits

Answer

The overall diameter divided by the central thickness

Answer

The percentage of water content in the material

Question 3

A long-time soft contact lens wearer complains of increasing itchiness, mucous discharge, and a foreign body sensation that is worse after removing the lenses. Slit-lamp examination of the everted upper eyelid reveals large papillae. Which of the following conditions is the most likely diagnosis?

Accepted Answer

Giant Papillary Conjunctivitis (GPC)

Answer

Microbial Keratitis

Answer

Corneal Neovascularization

Answer

Superior Limbic Keratoconjunctivitis (SLK)

Question 4

A technician is assessing the fit of a new soft contact lens and observes minimal movement with the blink, conjunctival vessel blanching at the limbus, and the patient reports that vision is clear initially but becomes uncomfortable after a short period. What is the most appropriate adjustment?

Accepted Answer

Select a lens with a flatter base curve (larger BC number)

Answer

Increase the plus power of the lens

Answer

Select a lens with a steeper base curve (smaller BC number)

Answer

Decrease the overall diameter of the lens

Question 5

Which type of contact lens care system requires a mandatory neutralization step to prevent severe chemical irritation to the cornea upon lens insertion?

Accepted Answer

Hydrogen peroxide-based system

Answer

Multipurpose solution (MPS)

Answer

Enzymatic protein removers

Answer

Saline solution for rinsing

Question 6

A patient requires a soft toric contact lens to correct their astigmatism. What is the primary purpose of the lens's stabilization design, such as prism ballast or thin zones?

Accepted Answer

To prevent the lens from rotating on the eye

Answer

To increase the water content for better comfort

Answer

To improve the lens's resistance to deposits

Answer

To make the lens easier to see for handling

A technician evaluating a rigid gas-permeable (RGP) lens with fluorescein observes a dark, central area of bearing on the cornea, surrounded by a bright green ring of pooling in the mid-periphery.What does this pattern indicate?

A technician evaluating a rigid gas-permeable (RGP) lens with fluorescein observes a dark, central area of bearing on the cornea, surrounded by a bright green ring of pooling in the mid-periphery.
What does this pattern indicate?