Severe dry eye symptoms developing in the first months after LASIK are primarily attributed to which mechanism?

• A Loss of goblet cells from topical anaesthetic use
• B Meibomian gland destruction by the excimer laser plume
• C Transection of corneal sensory nerves reducing afferent lacrimal reflex input ✓
• D Increased evaporation due to permanent loss of the lipid layer

Explanation

Creating the LASIK flap severs stromal nerves, reducing corneal sensory feedback from the ophthalmic division of the trigeminal nerve to the lacrimal functional unit. Decreased afferent signalling lowers reflex tear secretion and blink rate, producing transient neurotrophic dry eye that typically improves over 3 to 6 months as nerves regenerate. SMILE spares the central subepithelial plexus better, hence less dry eye. The other mechanisms do not explain post-LASIK dryness.

Reference: Ganong, Review of Medical Physiology, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.