RESUMO
Background: The accurate measurement of the horizontal corneal white-to-white [WTW] diameter is essential and has multiple applications in the field of ophthalmology whether medical or surgical. There are many means of measuring the horizontal white-to-white, which includes the Pentacam, the IOL Master and Manual Calipers. Both the Pentacam and Manual Calipers measure the external white-to-white diameter, whereas the IOL Master measures the internal white-to-white diameter
Objective: The aim of this study is to measure the accuracy of the Pentacam white-to-white camera in measuring the horizontal corneal WTW diameter in comparison to the Manual Calipers, which is considered to be the basic standard
Patients and Methods: The study was a cross sectional one, conducted at Maghrabi Eye Hospital, Cairo, Egypt. It was conducted in accordance with the ethical standards stated by the Ethical Committee of Ain Shams University. Informed consent was obtained from each participant following the explanation of the academic nature of the study
Results: Our study compared the accuracy of the Pentacam HR to the Manual Calipers and found a strong correlation between both methods regarding all parameters. A difference of 0.44 +/- 0.17 mm was found between the manual calipers and the Pentacam [HVID Automated] measurements and a lesser difference of 0.24 +/- 0.27 mm when comparing the manual calipers with the Pentacam manual digital calipers. On the other hand, the difference between the 2 methods of the Pentacam measurement used was 0.19 +/- 0.13 mm. All of which, showed a highly significant correlation
Conclusion: The Pentacam gives larger WTW measurements than the manual calipers as it relies on the gray scale analysis of the HVID in the iris image display