A Study of Axial Length, Keratometry, and the Predictability of SRK Formula in Intraocular Lens Power Calculation in Southern Thai Patients

Prut Hanutsaha, M.D.,
Visootr Chayakul, M.D., Dr. Med.
Department of Ophthalmology, Faculty of Medicine, Songklanagarind Hospital Prince of Songkla University Haadyai 90110

ABSTRACT The three hundred thirty one patients (378 eyes) underwent cataract extraction and posterior chamber lens implantation in Songklanagarind Hospital from January 1, 1986 to December 31, 1987 was retrospectively studied. The mean values of the keratometry in females were 45.00 diopter and 43.99 diopter in males, and were statistical significant difference (P = 2.60 x loll).

The axial length in males (23.55mm.) and females (22.92 mm.) were also statistical significant difference (P = 3.82 x 1012). Vision by calculation from the SRK formula is 64 percent within +1-1 diopter. However, if we calculate with the new formula which is adapted for Thai patients, the vision is 72 percent within +1-1 diopter. But in the cases that we can not calculate the in traocular lens power, we can use +17.5 diopter as the standard intraocular lens power, the result of the vision is 48 percent within +1-1 dioper.

Thai J Ophthalmol 1990; July - Dec 4 (2): 109-117