Posters

Pachymetric error for the apex, pupillary center, and thinnest point of the cornea on Pentacam corneal tomographer

Poster Details

First Author: S.Faria e Sousa BRAZIL

Co Author(s):    R. Foschini                    

Abstract Details

Purpose:

To determine the pachymetric errors of Pentacan for the apex, pupillary center and thinnest point of the cornea.

Setting:

HOSPITAL DAS CLINICAS DA FACULDADE DE MEDICINA DE RIBEIRÃO PRETO UNIVERSIDADE DE SÃO PAULO .BRASIL

Methods:

We selected 130 eyes (65 OD and 65 OS) with keratoconus with age varying from 12 to 25 years-old. Each eye was measured two times, with a time gap of 10 to 20 minutes, to enforce the repositioning of the patient to the instrument in each consecutive examination. The error was estimated by the coefficient of repeatability (CR) of Bland-Altman using the expression CR=1,96 √(2 ) SW; SW being the within-subject standard deviation. The standard error of CR was determined with the formula SE=(1.71√2 SW )/√N and the 95% CI calculated with the CR±1,98 SE.

Results:

The 95% CI for the coefficients of repeatability for the apex, pupillary center and the thinnest point of the cornea were about the same ranging from 14 to 17 µm.

Conclusions:

Considering the upper limit of the 95%IC of the coefficient of repeatability of the corneal pachymetry as the best estimate of the error of measurement, we wind up with the value of 17 µm for this error, which is the same for the apex, pupillary center and thinnest point of the cornea.

Financial Disclosure:

None