Management of Suspected Keratoconus with Corneal Crosslinking Request

Confirm the progression of keratoconus by comparing two pentacam reports before approving crosslinking treatment.

Assessment of Current Findings

The patient presents with blurry vision and has pentacam findings showing a K max of 50 D and corneal thickness of 420 μm, which are consistent with moderate keratoconus 1
A K max of 50 D indicates moderate keratoconus but is not by itself sufficient to warrant immediate crosslinking without evidence of progression 1
The corneal thickness of 420 μm is concerning as it approaches the safety threshold of 400 μm required for standard crosslinking protocols 2

According to the American Academy of Ophthalmology's Preferred Practice Pattern, documented progression is a minimal requirement before proceeding with corneal crosslinking 1
Progression is defined by at least 2 of the following: steepening of the anterior corneal surface, steepening of the posterior corneal surface, or thinning/increase in the rate of corneal thickness change from periphery to thinnest point 1
Serial topographic analysis with comparison of at least two pentacam reports taken at different time points is essential to document disease progression 1

While the patient shows signs of keratoconus, immediate crosslinking without documented progression could expose them to unnecessary risks 1, 2
The FDA approval for corneal crosslinking was based on studies that included patients with documented progressive keratoconus, not just the presence of keratoconus 1
The thin corneal thickness (420 μm) is particularly concerning as epithelial removal during standard CXL would likely reduce the stromal thickness below the 400 μm safety threshold 2

Schedule a follow-up pentacam examination in 3-6 months to compare with the current findings and assess for progression 1
Advise the patient to refrain from eye rubbing, which has been associated with keratoconus progression 1, 2
Consider adding a mast cell stabilizer if ocular allergy is present to reduce eye rubbing 1
If progression is documented on follow-up and CXL is still desired, special considerations for the thin cornea (420 μm) will be needed 2

If progression is documented and the cornea remains thin, modified approaches may be considered:
- Hypotonic riboflavin can be used to transiently thicken the cornea to reach the 400 μm threshold 2
- Alternative protocols such as contact lens-assisted CXL might be appropriate, though these are not FDA-approved in the United States 1, 2
- Referral to a specialist with experience in modified CXL protocols for thin corneas would be appropriate 2

Performing crosslinking without documented progression may expose the patient to unnecessary risks without clear benefit 1
Proceeding with standard CXL on a thin cornea (420 μm) without appropriate modifications risks endothelial damage 1, 2
Delaying treatment too long in a truly progressive case could lead to further vision deterioration and potentially require more invasive interventions 1, 3