Contact Lens Basics Flashcards

Which complication is characterized by blood vessels growing into the normally avascular cornea due to contact lens hypoxia?

Answer: Corneal neovascularization

Corneal neovascularization (pannus) occurs when the cornea is oxygen-deprived, stimulating blood vessel ingrowth from the limbus.

A rigid gas-permeable (RGP) lens that is too flat will typically:

Answer: Decentrate inferiorly and show excessive movement

A flat-fitting RGP lens rides on the apex of the cornea and moves excessively, often decentering inferiorly.

What does the term 'orthokeratology' refer to in contact lens practice?

Answer: Using rigid lenses overnight to temporarily reshape the cornea

Orthokeratology (ortho-k) uses specially designed rigid lenses worn overnight to temporarily flatten the cornea and reduce myopia.

Which contact lens design is most appropriate for a patient with irregular corneal astigmatism due to keratoconus?

Answer: Rigid gas-permeable lens

RGP lenses vault over the irregular corneal surface and provide a smooth optical surface via the tear lens, making them the preferred option for keratoconus.

Giant papillary conjunctivitis (GPC) associated with contact lens wear most commonly affects which ocular surface?

Answer: Upper tarsal conjunctiva

GPC is characterized by large papillae on the upper tarsal (palpebral) conjunctiva, often caused by lens deposits or mechanical irritation.

What is the recommended minimum waiting period after removing soft contact lenses before performing corneal topography for a new fit?

Answer: At least 2 weeks

Soft lenses can temporarily alter corneal shape; waiting at least 2 weeks ensures the cornea returns to its natural contour before topography.

A patient using hydrogen peroxide lens care systems must neutralize the solution before inserting lenses to avoid:

Answer: Severe ocular burning and pain

Inserting lenses still containing active hydrogen peroxide causes severe burning, stinging, and potential corneal damage.