Accuracy Advantage of Color LED Specular Reflection for Early Detection of Keratoconus

Zhang, Xin

Accuracy Advantage of Color LED Specular Reflection for Early Detection of Keratoconus

Saturday, April 26, 2014: 1:21 PM

Room 150 (Boston Convention and Exhibition Center)

Xin Zhang, MD, PhD Den Haag, Netherlands

Victor Arni De Paz Sicam, PhD, Rotterdam Ophthalmic Institute, Rotterdam, Netherlands

Nic J. Reus, MD, PhD, The Rotterdam Eye Hospital, Rotterdam, Netherlands

Annette Geerards, MD, FRCOphth, The Rotteram Eye Instiitute, Rotterdam, Netherlands

Narrative Responses:

Purpose
It has been shown that Color LED specular reflection technique produces more accurate corneal shape reconstruction compared to its Placido based counterparts. This study investigates the consequence of this in early detection of Keratoconus.

Methods
Observational study involving three groups: 1) 41 eyes (N) with no corneal abnormality, 2) 31 eyes (KC) with clear indication of keratoconus, 2) 31 fellow eye of group 2) with no clear indication of keratoconus (suspect keratoconus KCS). Corneal irregularity was measured using SRI, SAI and I-S indices and also using 3^rd and 4^th Order Higher order aberration (Zernike convention, 8^th order, 6 mm corneal zone) derived from corneal height measurements of Color LED Corneal Shape Analyzer (Cassini, i-Optics, The Hague, Netherlands) and Placido Corneal Topography (Keratron, Optikon, Rome, Italy).

Results
Significant differences were found between the Cassini and the Keratron SRI measurements for all three groups: Normal (1.04 ± 0.31 vs 0.45 ± 0.39, p < 0.01), KCS (1.55 ± 0.50 vs 0.70 ± 0.73, p < 0.01) and KC (2.39 ± 0.57 vs 1.98 ± 0.65, p < 0.01). Significant difference was found between Cassini and Keratron SAI (0.94 ± 0.31 vs 0.53 ± 0.20, p < 0.01) and 4^th order HOA (0.45 ± 0.11 vs 0.35 ± 0.17 µm, p < 0.01) of Normal eyes. For all other parameters, there were no significant differences observed.

Conclusion
In most corneal irregularity indicators, Color LED corneal shape analysis agrees well with Placido based corneal topography. However, the differences in SRI measurements suggest that earlier detection of Keratoconus is possible with this new technology which can help in the proper treatment planning of patients.