Accuracy of Intraocular Lens Power Estimation in Eyes Undergoing Phacovitrectomy for Proliferative Diabetic Retinopathy

ABSTRACT

PURPOSE: To evaluate the accuracy of intraocular lens (IOL) power estimation and the factors associated with outcome in eyes undergoing combined phacovitrectomy for proliferative diabetic retinopathy. METHODS: We performed a retrospective case review of 39 consecutive patients (44 eyes) that underwent phacovitrectomy for proliferative diabetic retinopathy. Axial lengths were measured using ultrasound (A-scan) and/or optical biometry (IOL Master). Achieved and predicted refractions were compared to calculate the mean postoperative refractive prediction error (ME) and the mean absolute prediction error (MAE). Systemic conditions of patients and several preoperative and postoperative factors related to the postoperative refraction were analyzed. RESULTS: The ME of 44 eyes were -0.23 +/- 0.52 diopters (D) and -0.23 +/- 0.47 D after 3 and 6 months, respectively (range, -1.40~+0.79 D). There was no statistically significant difference in the refractive outcomes between the refractive errors (p = 0.959). The MAEs were 0.45 +/- 0.35 D and 0.40 +/- 0.33 D after 3 and 6 months, respectively with no statistical significant difference between the results (p = 0.196). When comparing ME in the 20 eyes that achieved both results, ultrasound was more accurate than optical biometry (p = 0.002, 0.002). The factors associated with more inaccurate ME and MAE after phacovitrectomy were diabetic nephropathy and neovascular glaucoma. CONCLUSIONS: Combined phacovitrectomy in proliferative diabetic retinopathy showed small biometric errors within the tolerable range in most cases. Patients with neovascular glaucoma and diabetic nephropathy had more inaccurate postoperative refractive power. Both optical biometry and ultrasound should be used to estimate axial lengths for improving the accuracy of IOL power calculation.