EVALUATING THE EFFECTS OF EPIRETINAL MEMBRANE THICKNESS AND MACULAR HOLE SIZE ON IOL ACCURACY IN COMBINED PHACOEMULSIFICATION-VITRECTOMY PROCEDURES

To assess refractive outcomes following combined phacoemulsification and vitrectomy for epiretinal membrane (ERM) and macular hole (MH) from May 2020 to August 2024, focusing on the influence of ERM thickness and MH size on postoperative refractions and the accuracy of the IOL formula, specifically with the Barrett True K with Total Keratometry formula.

A retrospective analysis conducted within the high-volume ophthalmology practice, Ophthalmos Research and Educational Institute, in Nicosia, Cyprus, analysing 139 surgical cases with advanced biometric data and postoperative refractions.

We reviewed 139 cases, including 125 ERM and 14 MH cases. Key preoperative and postoperative variables—ERM thickness, MH size, axial length, and keratometry—were analysed in relation to refractive outcomes. Cases were evaluated for postoperative spherical equivalent accuracy within +/-0.5D and +/-1.0D. We also compared results with standard phacoemulsification cases without macular pathology over the same period to establish baseline refractive predictability with the Barrett True K with Total Keratometry formula.

Approximately 72% of ERM cases achieved a postoperative spherical equivalent within +/-0.5D, and 28% were within +/-1.0D.
Preliminary analysis suggests that greater ERM thickness preoperatively may lead to increased variability in refractive outcomes. A subset comparison indicated that cases with reduced postoperative ERM thickness, such as those from 420 µm pre-op to 350 µm or lower post-op, tended to show slightly improved predictability.
68% of MH cases achieved a postoperative spherical equivalent within +/-0.5D.
While the sample size of MH cases is smaller, initial findings suggest that larger preoperative MH sizes such as > 400μm may introduce more variability in refractive predictability, warranting close attention to IOL calculations in these cases.
Comparative analysis with standard phacoemulsification cases without macular pathology during the same period showed slightly better predictability with the Barrett True K with Total Keratometry formula, with a higher percentage achieving within +/-0.5D. This comparison reinforces the need for potential adjustments in IOL calculations when ERM or MH is present.

These findings indicate that specific preoperative factors, such as ERM thickness and MH size, can influence refractive accuracy in phacoemulsification and vitrectomy for ERM and MH. Adjustments to IOL formulas or calculation techniques may improve postoperative outcomes for patients with retinal pathology, aligning refractive predictability closer to that of standard phaco-only cases.