The accuracy and repeatability of optical biometry for cataract patients who have changed macular thickness with retinopathy

PURPOSE:The aim of this study was to compare the accuracy of optical and ultrasonic biometry for using IOL (Intraocular lens) power calculation between cataract patients groups who have increased retinal thickness with maculopathy and normal retinal thickness without maculopathy. MATERIAL & METHOD: The cataract patients who have increased retinal thickness with maculopathy including diabetic macular edema in 31 (50%), age related macular degeneration in 16 (26%) and epiretinal membrane in 15 (%24) were recruited to study from Ege University Medical Faculty Department of Ophthalmology. Fifty four patients were included to study without retinal pathology for control group. Preoperatively, all patients underwent complete ophthalmic examination including best-corrected visual acuity using a Snellen chart, Goldmann applanation intraocular pressure measurement, slit-lamp biomicroscopic examination, and dilated fundus examination was performed using 90D lens, additionally optic biometry (Nidek, Japanese), applanation A-scan ultrasonic biometry (Sonogage Eye mod, Cleveland) ophthalmological exams were performed with optical biometry (Al-Scan, , OH,USA) and posterior segment optical coherence tomography (Topcon 3D OCT-2000, Tokyo Japan). Success rate to targeted refraction of calculated intraocular lens power with SRK-T and SRK-2 formulas which detected by optical and ultrasonic biometry, at postoperative first month and 3th months were compared. RESULTS:The average age of maculopathy group was 67.65 ± 9 (49-82 years) and without maculopathy group was 66.98 ± 8 (24-82years). There was no significant difference between two groups for age, sex, axial length and keratometric variables (all of p value >0.05) but both groups was different according to preoperative central retinal thickness (maculopathy group - 282.52 ± 64µm; control group - 233.11 ± 13µm) and best corrected visual acuity (maculopathy group - 0.92 ± 0.51 logMAR ve control group - 0.68 ± 0.30 logMAR ) (p value ˂0.001 and 0.004 respectively). Mean aritmetical deviation from targeted refraction values using SRK-T formulas (in maculopathy group -0.06 D, in control group -0.11 D (p=0.658)) or SRK-2 formulas (in maculopathy group -0.10 D, in control group -0.04 D (p=0.585)) which detected by optical biometry and which detected by ultrasonic biometry using SRK-T formula (in maculopathy group -0.03 D, in control group 0.14(p=0.098) was not significantly difference between both groups. But mean aritmetical deviation from targeted refraction values using SRK-2 formula which detected by ultrasonic biometry(in maculopathy group 0.12 D, in control group 0.35(p=0.036)) was significantly difference between both groups. Mean absolute deviation from targeted refraction values using SRK-T formulas which detected by optical biometry in maculopathy group was 0.42 D, in control group was 0.43 D (p=0.90), using SRK-2 formula which detected by optical biometry in maculopathy group was 0.46 D, in control group was 0.44 D (p=0.76). On the other hand SRK-T formula which detected by ultrasonic biometry in maculopathy group was 0.44 D, in control group was 0.41 D (p=0.68), SRK-2 formula which detected by ultrasonic biometry in maculopathy group was 0.50 D, in control group was 0.47 D (p=0.73). CONCLUSİON: In cataract cases who have increased retinal thickness with maculopathy, optical and ultrasonic biometry methods for IOL power calculation have a similar success rate to achieve targeted refraction if they have adequate fixation stability.