Intrapersonal comparison of initial axial length, keratometric readings, and intraocular lens power over a 6-month interval using an IOLMaster device

PURPOSE: In order to improve current biometry practice, we investigated changes in axial length (AL), keratometry (K), and intraocular lens (IOL) power measured by the IOLMaster in adults within a 6-month period at the outpatient eye clinic, King Chulalongkorn Memorial Hospital, Bangkok, Thailand. PATIENTS AND METHODS: This was a nonrandomized prospective cohort study. The AL, steepest K, flattest K, and IOL power of nondilated eyes were measured at the initial examination and later at 6 months by the IOLMaster. Changes in AL, K, and IOL power using the SRK (Sanders, Retzlaff, and Kraff)-T formula within 6 months were compared using the paired-sample t-test. RESULTS: The study comprised 90 eyes from 90 patients. The mean age of the patients was 62.99±13.95 years (range 28–87 years). Mean values and standard deviation for AL, steepest K, flattest K, and IOL power at initial visit and 6 months later were 23.56±1.51 mm and 23.56±1.52 mm (P=1.0; 95% confidence interval [CI] −0.01 to 0), 44.94±1.37 D and 44.98±1.43 D (P=0.96; 95% CI −0.13 to 0.04), 43.85±1.43 D and 43.89±1.36 D (P=0.93; 95% CI −0.02 to 0.07), and 20.27±4.12 D and 20.15±4.51 D (P=0.99; 95% CI −0.05 to 0.29), respectively. CONCLUSION: There was no statistically significant difference in AL (P=1.0), both K (P=0.96, P=0.93), or IOL power (P=0.99) within the 6-month period using the IOLMaster. Remeasurement at 6 months may be required in some cases, but should not be routine.