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To determine whether inter-ocular differences in axial length (AL), corneal power (K), and adjusted emmetropic IOL power (EIOLP) and inter-visit differences in these ocular biometric values measured on different days are related with refractive outcomes.
We retrospectively reviewed 296 patients who underwent phacoemulsification. Patients underwent measurement of ocular biometry twice (1 to 4 weeks before and on the surgery day). Patients with interocular AL differences (IALD) ≥ 0.2 mm or interocular K differences (IKD) ≥ 0.5 D or interocular EIOLP differences ≥ 0.5 D were considered to have interocular biometry differences. Patients were divided into 3 groups; group S (similar interocular biometry), group P (interocular differences persisted after second measurement) and group D (interocular difference diminished after second measurement), and postoperative refractive outcomes (mean absolute errors (MAE)) were compared among 3 groups.
A total of 296 patients were included (221 in group S, 41 in group P, 44 in group D). IALD and IKD were significantly greater in group P and D than group S on first measurement. (IALD, group S, 0.05 mm, group P, 0.27 mm, group D, 0.20 mm, p<0.001; IKD, group S, 0.21 D, group P, 0.67 D, group D, 0.61 D, p<0.001). IALD and IKD were significantly decreased on second measurement in group D (IALD 0.20 to 0.14 mm, IKD 0.61 to 0.43 D). Postoperative MAE measured by second examination was significantly lesser than MAE measured by first examination in group D (0.55 D vs 0.46 D, p=0.029), however no significant differences in the other two groups (group S, 0.47 D vs 0.47 D, group P, 0.64 D vs 0.68 D).
Interocular biometry differences were associated with refractive outcomes after phacoemulsification. When interocular biometry differences decreased on repeated evaluation performed on different day, biometric measurements with reduced interocular differences may assure more accurate refractive outcomes.