Abstract
Purpose :
There has been increased interest in defining early corneal topographical changes in younger subjects prior to the onset of keratoconus. If a topographical index can predict the development of corneal ectasia, early intervention may prevent the poor outcomes commonly associated with keratoconus when left untreated or treated late in the disease. A group in Israel recently described use of a color-coded topographic map analysis as a primary indicator. The origin of this method is dated but it was utilized to help seek out primary indicators of early diagnosis to determine if this method was beneficial in the interpretation of our scans.
Methods :
Our clinical program has run > 3000 scans on children and adolescents over the past 3 years. A study of the first 400 scans were categorized based on interpretation of the color-coded corneal topography on the Pentacam (Oculus, Wetzlar, Germany). The reviewers (3) categorized the shape (axial (front) - Topometric/KC-Staging map) ranging from round to unclassifiable which then was correlated with parameters associated with corneal changes (ART Max, pachymetry, the Belin- Ambrósio A, B, C, and Final D), as well as, refractive error (cylinder, spherical equivalent).
Results :
There were 200 subjects in this study (53% male) with a mean age of 11.2 + 2.81 (SD) years (range: 5-20 years), 49% Hispanic, 49% Black. The range of refractive error was: cyl 0.25-6.75, sph eq -3.28-+3.30. An analysis compared the shape as determined by the reviewers to other corneal factors. The results revealed no significant correlation with these factors: ART Max, pachymetry, A, D, C, Final D. There was a statistically significant but clinically irrelevant negative correlation between the shape and the amount of spherical equivalent and cylinder.
Conclusions :
The current understanding of the development of keratoconus is that the posterior surface of the cornea changes prior to the front surface. Based on this statement, qualitative interpretation of the front corneal surface would not be expected to demonstrate a significant correlation as a potential indicator of risk toward keratoconus development as opposed to current corneal indices. Our data confirms that interpreting color-coded corneal topography would not be beneficial in children nor adolescents that have no other visible changes in topography.
This is a 2020 ARVO Annual Meeting abstract.