Inner Microcystoid Changes Inadequate as Postoperative Acuity Biomarker

Preoperative inner microcystoid changes were present in more than half of eyes with epiretinal membrane (ERM) and concurrent glaucoma, and are likely poor prognostic biomarkers of surgical outcomes, according to a study published in Ophthalmology Retina. The research employed optical coherence tomography (OCT) images to identify potential biomarkers of visual acuity (VA) outcomes after pars plana vitrectomy (PPV) for idiopathic ERM. 

Researchers reviewed a total of 103 eyes of 103 patients with ERM and glaucoma for a mean of 656±421 days after PPV with membrane peel (MP), surgery with glaucoma being classified as open angle in 98 (95.1%) eyes and closed angle in 5 (4.9%) eyes. VA improved from 0.72±0.48 logMAR (20/105) to 0.55±0.51 logMAR (20/71) at 6 months and to 0.50±0.56 logMAR (20/63) at final follow-up (P <.001 for both timepoints). While vision improved significantly in patients with mild and moderate disc cupping, improvements were statistically insignificant in patients with advanced disc cupping. Moreover, investigators note that, “advanced disc cupping was the only independent predictor of worse vision outcomes on multivariate analysis.” 

The investigation shows patients with ERM and concurrent glaucoma experienced worse vision outcomes compared with eyes with ERM alone — particularly those with advanced disc cupping. Advanced disc cupping is independently associated with poorer visual outcomes after surgery in patients with ERM and glaucoma compared with individuals with mild and moderate disc cupping, the report shows. 

Regarding OCT analysis, inner microcystoid changes were more likely to occur in eyes with advanced disc cupping. Further, patients with preoperative inner microcystoid changes on OCT displayed worse vision at all time points compared with patients’ eyes without this OCT feature.

Patients with preoperative inner microcystoid changes (n=59, 57.3%) had significantly worse outcomes at preoperative, postoperative month 6, and final VA compared with those without inner microcystoid changes (P =.028, P =.004 and P =.007, respectively). Researchers then compared patients’ eyes with a matched control group of 139 eyes without glaucoma. Individuals with ERM and glaucoma displayed a higher rate of microcystic changes both preoperatively (P <.001) and at postoperative month 6 (P <.001). Patients with both conditions also had a worse VA at 6 months (P =.03) and final follow-up (P =.04). In multivariate analysis, advanced disc cupping was the only factor independently correlated with worse 6-month (P =.01) and final (P =.007) VA.

Researchers utilized a previously described ERM grading scale for OCT analysis with a primary outcome of VA at postoperative month 6. 

“Field deterioration occurred most prominently in the superior outer and inferior outer sectors, areas known to have the thinner RNFL in control (nonglaucomatous) eyes. These findings suggest that (those) with more advanced glaucoma and RNFL loss may be more susceptible to central visual field deterioration, helping to explain the worse vision outcomes at 6 months and final follow up,” researchers explain.

Limitations of this retrospective study include the fact that results of visual field testing, retinal nerve fiber layer (RNFL) thickness, and ganglion cell layer (GCL) thickness measurements were not available for analysis. Therefore, correlation of visual and OCT findings to glaucoma severity could not be performed. Further, use of Snellen acuity with habitual correction may have underestimated VA gains and other symptoms associated with ERM were not quantified.

Findings may better inform preoperative expectations and shed light on surgical strategies for patients with ERM and glaucoma — particularly those with advanced disc cupping.

Reference

Peck T, Salabati M, Mahmoudzadeh R,et al. Epiretinal membrane surgery in eyes with glaucoma: visual outcomes and clinical significance of inner microcystoid changes. Ophthalmol Retina. 2022;99(3):241-252. doi:10.1016/j.oret.2022.02.016