Summary Statement:Combined phacovitrectomy as primary repair surgery for rhegmatogenous retinal detachment (RRD) included a small biometric error that was within the tolerable range in most cases.The biometry used for IOL power selection must be checked by comparing with the fellow eye and the known refraction, especially in macula-off RRD cases. 3ABSTRACT PURPOSE: To evaluate the accuracy of intraocular lens (IOL) power estimation in eyes having phacovitrectomy for rhegmatogenous retinal detachment (RRD).METHODS: Retrospective case series review of 100 consecutive eyes that underwent phacovitrectomy for RRD. Axial lengths (ALs) were measured using optical biometry and/or ultrasound. Achieved and predicted refraction were compared to calculate the mean postoperative refractive prediction error and the mean absolute prediction error (MAE).Factorial analysis of variance (ANOVA) models were developed to assess outcome overall and between subgroups. RESULTS: 95 eyes had postoperative refraction; 41 macula-on (43%), 54 macula-off (57%).The mean postoperative prediction error was -0.34 ± 0.89D. There was no statistical significant difference in the refractive outcomes between macula-on and macula-off groups (p>0.05). Overall, using MAE as the outcome measure, optical biometry was more accurate then ultrasound (p=0.040). However, significantly more ultrasound measured ALs were selected for IOL power estimation in macula-off group compared to the macula-on group (p=0.016).CONCLUSIONS: Combined phacovitrectomy in RRD included a small biometric error that was within the tolerable range in most cases. The accuracy of AL used for IOL power calculations must be checked by comparing with the fellow eye and the known refraction, especially in macula-off RRD cases.4

Accurate measurement of axial length is essential for preventing refractive surprises postoperatively. This can often be difficult in eyes with RRDs. Optical biometry may underestimate axial length in macula off rhegmatogenous retinal detachments; however, we present a novel way of adjusting the optical biometry to accurately measure the axial length. METHODS: Axial lengths (ALs) were measured using OB with user adjustment to identify a posterior peak corresponding to the eye's AL and ultrasound (US). These measurements were compared and analysed for accuracy to each other and the post-operative OB as a more accurate indication of the eye's AL.RESULTS: User-adjusted OB was similar to US and post-operative OB measurements.There was no statistically significant difference between the means of the AL measurements derived from user-adjusted OB and ultrasound AL (p=0.964). User-adjusted OB was not statistically significantly different to post-operative OB (p=0.242). Compared to postoperative OB, IOL power was within 0.5 Dioptre in 12 out of 13 cases (92%; 95% confidence interval (77.8%, 100.0%) for user-adjusted OB, and in only 10 out of 13 cases (77%; 95% confidence interval (54.0%, 99.8%) of US measurements. 4 CONCLUSIONS: User-adjusted OB may be used as an alternative method for the measurement of AL in macula-off RRD for primary repair by combined phacovitrectomy.OB will, however, require assessment of agreement with US AL in cases where a posterior peak is not easily identifiable. We have also shown that user-adjusted OB may outperform US AL when calculating IOL power; however, a larger study may be needed to confirm this.