Short-term scleral lens wear in keratoconic patients may cause flattening of the anterior cornea, and practitioners should be aware of these changes, considering scleral lenses may mask the signs of keratoconus progression, a study in Cornea reports.

Researchers also found a history of corneal crosslinking (CXL) did not guarantee corneal shape stability after scleral lens wear.

Investigators fit nine keratoconic patients (14 eyes) with 18.5mm scleral contact lenses. The subjects were divided into two groups: seven eyes without a history of CXL and seven that had previously undergone CXL procedures. Researchers performed corneal topography at baseline and again after two and five hours of lens wear. They then evaluated the differences for simulated flat (Kflat), steep (Ksteep) and maximal (Kmax) corneal curvatures, central corneal astigmatism and central cornea thickness.

The study found no statistically significant difference between the non-CXL and CXL groups in any of the measures. Additionally, both groups exhibited a statistically significant reduction in the keratometric values of Ksteep and at the corneal apex with scleral lens wear.

Other study highlights included:

  • Ksteep decreased on average from 53.1D at baseline to 52.4D at five hours of scleral lens wear
  • Kmax decreased from 56.7D to 55.8D
  • Central corneal astigmatism decreased from 7.2D to 6.3D
  • Kmax showed a trend toward more flattening in the non-CXL group
  • Central cornea thickness showed significant thickening over time from baseline (451mm) to five hours (458mm) of scleral lens wear

“Our results clearly show that despite an absence of lens–cornea contact with scleral lenses, significant corneal flattening can occur after short-term wear,” the researchers wrote in their paper.

Severinsky B, Fadel D, Davelman J, et al. Effect of scleral lenses on corneal topography in keratoconus: a case series of cross-linked versus non–cross-linked eyes. Cornea. May 21, 2019. [Epub ahead of print].