Abstract
Purpose :
Combining vitrectomy and cataract surgery is effective for treating coexisting pathologies, and provides patients with rapid visual rehabilitation. However, it is unclear if intraocular lens (IOL) calculations should be adjusted in combined procedures. The study compares refractive outcomes of combined phacovitrectomy to those of cataract surgery alone.
Methods :
A retrospective review of patients undergoing surgery over a 3-year period by a single anterior segment surgeon and a single posterior segment surgeon was performed. The difference between the predicted and actual refractions in two groups was compared: 49 eyes undergoing combined vitrectomy and cataract surgery and a control group of 54 eyes undergoing cataract surgery alone. Indications for retinal surgery were limited to epiretinal membrane, macular hole and non-clearing vitreous hemorrhage. Predicted refractive error (RE), based on SRK/T and Holladay 1 formulas, was compared to final RE, and the relationship between pre-operative central foveal thickness (CFT) and final RE was assessed.
Results :
Median visual acuity improved from 20/40 to 20/20 in the control group, and improved from 20/60 to 20/30 for combined procedures. The mean difference in predicted and final RE in the control group was 0.38±0.38 D and 0.40±0.37 D, based on SRK/T and Holladay 1 respectively. In the combined group, the mean difference was 0.57±0.53 D and 0.55±0.53 D for SRK/T and Holladay 1, respectively. This difference between groups was statistically significant for SRK/T (P=0.033) but not Holladay 1 (P>0.05). Regardless of the formula used, final RE was neither significantly hyperopic nor myopic as compared to the target (P>0.05). When stratifying patients according to macular CFT, a trend toward decreased accuracy was present but correlation analysis did not show a significant relationship.
Conclusions :
There was no difference in refractive outcomes following combined procedures as compared to cataract alone when the Holladay 1 formula was used for IOL calculations. There was a statistically significant difference with the SRK/T formula, however the absolute difference was small and likely not clinically significant. Combined phacovitrectomy appears to deliver as predictable refractive results as cataract surgery alone. A correlation between CFT and RE was suggested but not significant.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.