COA Contact Lens Fundamentals 3

Question 1

Which condition is most directly associated with chronic corneal hypoxia from extended contact lens wear?

Accepted Answer

Corneal neovascularization (pannus)

Answer

Pterygium formation

Answer

Pinguecula

Answer

Fuchs endothelial dystrophy

Question 2

What is the most appropriate initial management for a contact lens wearer who presents with a red, painful eye and a central corneal infiltrate?

Accepted Answer

Immediately discontinue lens wear and refer to a physician for evaluation of possible microbial keratitis

Answer

Refit with a daily disposable lens

Answer

Prescribe artificial tears and resume lens wear in 24 hours

Answer

Switch to hydrogen peroxide disinfection and continue lens wear

Question 3

What is the purpose of the sagittal depth (sag) in contact lens fitting?

Accepted Answer

It describes the vault of the lens over the cornea, determining how the lens sits relative to the corneal surface

Answer

It measures the oxygen transmissibility of the lens material

Answer

It indicates the dioptric power needed to correct the patient's refractive error

Answer

It measures the thickness at the lens center to calculate Dk/t

Question 4

A patient switches from glasses (spectacle Rx: -5.00 D) to contact lenses. Due to vertex distance, the expected contact lens power will be approximately:

Accepted Answer

Less minus than the spectacle prescription

Answer

More minus than the spectacle prescription

Answer

Exactly the same as the spectacle prescription

Answer

More plus than the spectacle prescription

Question 5

Which parameter is most important when fitting a toric soft contact lens?

Accepted Answer

The axis orientation and stabilization mechanism to minimize lens rotation

Answer

The base curve radius only

Answer

The lens overall diameter and water content

Answer

The back vertex power of the spherical component only

Question 6

When teaching a patient to insert a soft contact lens, which instruction is most important for preventing infection?

Accepted Answer

Wash and dry hands thoroughly before handling lenses

Answer

Always insert the lens straight from the storage case without rinsing

Answer

Wear lenses for extended periods to reduce handling frequency

Answer

Clean the lens only once per week to preserve the disinfecting solution

Question 7

Which contact lens parameter should be steepened if a patient's RGP lens shows excessive movement and falls inferiorly with each blink?

Accepted Answer

Base curve should be steepened (smaller radius of curvature)

Answer

Overall diameter should be decreased

Answer

Center thickness should be reduced

Answer

Back vertex power should be increased