SNPs in the COL5A1 region, which regulate normal variation in CCT, may play a role in the thinning associated with keratoconus.

No abstract

Purpose: To compare the ability to detect preoperative ectasia risk among LASIK candidates using classic ERSS (Ectasia Risk age and RSB provided 100% sensitivity and 94% specificity, with better AUC (0.989; 95% CI: 0.969 to 0.998)

Background/Aims To develop parameters using a combination of optical coherence tomography (OCT) and videokeratography to ‘early’ detect keratoconus. Methods We performed videokeratography, wavefront analysis and measured OCT indices on 180 normal, 46 moderate keratoconus, 54 early keratoconus, 7 ‘forme fruste’ keratoconus and 16 keratoconus ‘suspect” eyes, to determine the most sensitive parameters for separating these groups. Results A combination of videokeratography and OCT indices (I-S value and Minimum pachymetry) was statistically the most significant in separating the keratoconus groups from normals (P<.001). Using a newly derived index, the Minimum pachymetry divided by the I-S value (PA/I-S index) with a cut off of 100, we could identify 100% of “early” and ‘forme fruste’ keratoconus as being abnormal with 7 normals misclassified (misclassification rate of 2.7%). By adding keratoconus ‘suspects’ to the analysis and an I-S value of 1.2 as a cut of point, we classified 5 ‘suspects’ as normal and 11 normals as abnormal (misclassification rate 7.8%). The PA/I-S index, with a cut of point of 100, reduced this misclassification rate to 4.4%. Conclusion These results suggest that OCT combined with videokeratography may be more useful for differentiating mild forms of keratoconus, than videokeratography alone.

Corneal epithelial thickness was first available using digital very-high-frequency ultrasound. Advances in anterior segment optical coherence tomography enabled such fundamental evaluation, which accelerated progress. Such knowledge significantly impacts safety and efficacy of refractive surgery, and also allows for significant improvement for therapeutic procedures. VIDEO ABSTRACT.