COA Contact Lens Fundamentals 2

Question 1

A patient complains of giant papillary conjunctivitis (GPC) after months of soft contact lens wear. What is the most likely cause?

Accepted Answer

Mechanical irritation and immune response to lens deposits or the lens edge

Answer

Corneal neovascularization from lens hypoxia

Answer

Bacterial infection from contaminated lens case

Answer

Lens dehydration causing anterior surface dryness

Question 2

What does 'Dk/t' represent in contact lens science?

Accepted Answer

Oxygen transmissibility, calculated as permeability divided by lens thickness

Answer

Lens diameter divided by thickness

Answer

Diffusion coefficient of the cleaning solution

Answer

Dioptric power adjusted for lens thickness

Question 3

During a soft contact lens over-refraction, what is the primary purpose of this procedure?

Accepted Answer

To determine the final contact lens power needed by refracting over a trial lens

Answer

To measure the fit of the trial lens on the cornea

Answer

To assess corneal curvature changes from lens wear

Answer

To evaluate the tear film stability under the lens

Question 4

What is orthokeratology (ortho-k)?

Accepted Answer

Use of specially designed rigid lenses worn overnight to temporarily reshape the cornea

Answer

Surgical reshaping of the cornea using a laser

Answer

An exercise regimen to strengthen extraocular muscles

Answer

A method of measuring corneal curvature with a keratometer

Question 5

Which fluorescein staining pattern is commonly associated with a poorly fitting rigid gas-permeable lens causing 3 and 9 o'clock staining?

Accepted Answer

Desiccation of the corneal epithelium at the 3 and 9 o'clock limbal positions due to inadequate tear coverage

Answer

Corneal hypoxia causing diffuse superficial punctate keratitis

Answer

Bacterial keratitis from contaminated lens storage

Answer

Allergic reaction to lens care solution preservatives

Question 6

What is the recommended patient education regarding hydrogen peroxide contact lens care systems?

Accepted Answer

Lenses must complete a full neutralization cycle (minimum 6 hours) before insertion

Answer

Lenses can be inserted immediately after placing them in the peroxide solution

Answer

Hydrogen peroxide systems can be used with any contact lens type including daily disposables

Answer

Rinsing with tap water is acceptable after the neutralization step

Question 7

A keratometry reading is 44.00 D @ 180 / 46.00 D @ 090. When fitting a spherical soft contact lens, the effective lens power on the eye will primarily correct which component?

Accepted Answer

The spherical equivalent, leaving residual astigmatism uncorrected

Answer

The full astigmatic correction with no residual error

Answer

Only the steepest meridian power

Answer

Only the flattest meridian power