Differentiating Normal Corneas From Those with Form Fruste Keratoconus
It is possible to differentiate normal corneas from those with form fruste keratoconus by measuring the posterior cornea with a dual Scheimpflug Analyzer, noted David Smadja, MD, researcher associate at the Institute of Nanotechnology and Advanced Materials at Bar Ilan University in Tel Aviv, Israel, during the American Society of Cataract and Refractive Surgery’s 2018 annual meeting in Washington, DC.
Dr. Smajda and colleagues conducted a retrospective comparative study involving 201 normal corneas in 104 participants. They had postop LASIK follow-up of 36 months that were imaged with a Placido-Dual Scheimpflug system, and compared to 39 contralateral normal eyes of clinically evident keratoconus in the fellow eye. Investigators measured and categorized posterior surface variables. Among the results:
- Differences related to asymmetry and elevation of the posterior surface were significantly different between the 2 groups.
- Eccentricity and curvature-related parameters were not significantly different.
- Posterior I-S value and the asphericity asymmetry index best differentiated normal corneas and form frust keratoconus.
Smadja D. Differences in posterior corneal features in normal corneas and subclinical keratoconus. Talk presented at: 2018 ASCRS-ASOA Annual Meeting; April 13-17, 2018; Washington, DC.