Question

How is the risk of microbial keratitis in Ortho-K lenses compared with overnight wear of other contact lens modalities?

A. Ortho-K carries higher risk.
B. Other modalities pose a greater risk.
C. Both have equal risk.
D. Risk depends on lens material, not modality.

Answer 1

Option A. Ortho-K lenses carry a higher risk of microbial keratitis compared to other lens modalities due to their overnight wear design, which promotes conditions conducive to microbial growth.

Step-by-step explanation:

The risk of microbial keratitis in orthokeratology (Ortho-K) lenses compared with overnight wear of other contact lens modalities is somewhat higher. Microbial keratitis, particularly when caused by pathogens like Staphylococcus epidermidis and Pseudomonas aeruginosa, poses a significant risk to contact lens users because these microorganisms adhere well to lens surfaces.

Moreover, conditions like Acanthamoeba keratitis are exacerbated by the presence of contact lenses, particularly in improper hygiene situations such as wearing lenses while swimming or in a hot tub. The risk of infection can be reduced through proper lens care, including avoiding wearing lenses overnight. However, Ortho-K lenses are specifically designed for overnight wear to reshape the cornea, which inherently carries a higher risk.

While risk factors include but are not limited to contact lens material, the modality of wearing lenses overnight, as with Ortho-K, typically presents a higher risk for microbial keratitis infection due to the extended period lenses are in contact with the eye, creating a favorable environment for microbial growth.