Central and peripheral corneal thickness measured with the TOPCON specularmicroscope SP-2000P

Authors
Citation
P. Cho et Sw. Cheung, Central and peripheral corneal thickness measured with the TOPCON specularmicroscope SP-2000P, CURR EYE R, 21(4), 2000, pp. 799-807
Citations number
16
Categorie Soggetti
da verificare
Journal title
CURRENT EYE RESEARCH
ISSN journal
02713683 → ACNP
Volume
21
Issue
4
Year of publication
2000
Pages
799 - 807
Database
ISI
SICI code
0271-3683(2000)21:4<799:CAPCTM>2.0.ZU;2-C
Abstract
Purpose. Modern refractive surgery and follow up relies on a knowledge of c orneal thickness (CT) and shape, and the reliability of modern instrumentat ion providing such data is important. This study sought to determine the pe rformance of the TOPCON SP-2000P specular microscope in measuring CT. The a ims of this study were: (a) to determine if there is any difference between the CT results obtained from the first image, the clearest of three images and the mean of measurements from three images; (b) to determine the corre lation between central and peripheral CT and (c) to investigate the reliabi lity (repeatability and reproducibility) of the SP-2000P in the determinati on of central and peripheral CT. Methods. The central and peripheral CT measurements shown on the first (f), the clearest (c) of three images and the mean (m) CT shown in three images captured with the SP-2000P of 43 subjects were compared. All images were c aptured by the same examiner. Nineteen of the subjects (male) returned on a nother day and measurements were taken by two examiners. Results. fCT, cCT and mCT were not significantly different from each other. The intraclass correlation coefficients (ICC) between the three values wer e > 0.9 for all corneal locations measured. However, the variability in the differences between fCT and cCT was relatively greater for peripheral CT ( except temporal). The peripheral CT values obtained were all significantly greater than the central CT, and statistically significant correlations wer e found between the central and each of the peripheral thickness. There was no statistically significant between-visit or between-examiner differences in the central or peripheral CT. The ICC values for between-visit differen ces for central and temporal measurements were > 0.9 but for the other corn eal locations, the ICC values were 0.81 to 0.88. For between-examiner diffe rences, the ICC value was 0.82 for inferior CT and > 0.9 for the other four CT. Conclusions. Differences in CT measurements obtained from the first and cle arest images captured by the SP-2000P were not statistically significant bu t can be clinically significant for peripheral CT. We therefore suggest the use of the CT value obtained from the clearest of three images. For every unit change in central CT, there is an approximately equivalent change in p eripheral CT. Based on the ICC values, the SP-2000P showed very good repeat ability and reproducibility in the determination of central CT. For the det ermination of peripheral CT, the repeatability and reproducibility of the S P-2000P were good and reasonably good respectively. These findings have rel evance to the measurement of the cornea before and after refractive surgery .