Speaking at SECO, which was held in Atlanta earlier this month, the corneal specialist told delegates that the patient will have an increase of more than 1.00D in steepest keratometry readings, an increase of at least 1.00D in regular astigmatism and a myopic shift of at least 0.50D.
He added that the candidate patient will have the presence of central or inferior steepening with axial topography consistent with keratoconus, the steepest manual K reading of at least 47, and a corneal thickness of at least 300–400µm at the thinnest point.
Describing the cross linking procedure, which creates bonding between collagen fibres in the cornea, he told delegates: “We naturally self cross-link our corneas as we get older. A 70-year-old patient is at much less risk of developing keratoconus than a 20-year-old because that cornea has already been cross-linked. It’s debated whether there’s a benefit to treating older patients.”
Dr Kim also provided insight into the debate around removal of the epithelium, explaining that riboflavin B2 penetrates the cornea better when it is removed. He added: “The problem is that some patients have had delayed healing because of epithelial infections or scarring.”
Delegates were advised that riboflavin can be applied with stromal punctures “to help it penetrate” the cornea, but added: “The issue is: will you get a sustained and high enough level to have the effect of cross linking?”