Contact Lenses & Fitting Flashcards

Giant papillary conjunctivitis (GPC) is defined by papillae on the upper tarsal conjunctiva that are larger than:

Answer: 1.0 mm

GPC is characterized by papillae larger than 1.0 mm on the upper tarsal conjunctiva, differentiating it from normal papillary response.

Contact lens-induced acute red eye (CLARE) is most commonly associated with colonization by which category of organism?

Answer: Gram-negative bacteria

CLARE is most commonly associated with Gram-negative bacterial colonization of extended wear contact lenses, with endotoxins triggering the inflammatory response.

Which contact lens-related complication presents with deep stromal infiltrates, significant anterior chamber reaction, mucopurulent discharge, and severe pain, representing the most vision-threatening condition?

Answer: Microbial keratitis

Microbial keratitis presents with deep stromal infiltrates, severe pain, and discharge, and represents the most serious and vision-threatening contact lens-related complication.

Superior epithelial arcuate lesions (SEAL) are primarily caused by which mechanism?

Answer: Mechanical trauma from the edge of a soft contact lens

SEALs result from mechanical trauma where the upper eyelid forces the peripheral edge of a soft lens against the superior corneal epithelium, creating an arcuate split.

Which exposure is considered the primary risk factor for Acanthamoeba keratitis in contact lens wearers?

Answer: Exposure to tap water or swimming while wearing lenses

Water exposure (tap water, swimming, showering with lenses) introduces Acanthamoeba to the lens environment and is the primary modifiable risk factor for Acanthamoeba keratitis.

Corneal neovascularization in contact lens wearers is primarily driven by which pathophysiologic mechanism?

Answer: Chronic hypoxia inducing VEGF release from the corneal epithelium

Chronic corneal hypoxia triggers vascular endothelial growth factor (VEGF) release, stimulating new vessel ingrowth from the limbal vascular plexus into the avascular cornea.

A contact lens patient presents with a small (<1 mm), round, white peripheral stromal infiltrate with overlying epithelial staining, minimal pain, and no anterior chamber reaction. The most likely diagnosis is:

Answer: Contact lens peripheral ulcer (CLPU)

CLPU presents as a small, round, peripheral stromal infiltrate with overlying epithelial staining in extended wear users, and is distinguished from microbial keratitis by its peripheral location, small size, and minimal pain.