In the JournalsPerspective

Eyes experience thinning of ganglion cell-inner plexiform layer after epiretinal membrane surgery

Eyes that underwent epiretinal membrane surgery experienced progressive thinning of the ganglion cell-inner plexiform layer and worsening Humphrey visual field mean deviation at 5 years’ follow-up, according to a study.

“Our 5-year findings that there is progressive thinning of the inner retina after vitrectomy surgery lend further support to a causal association of vitrectomy surgery with risk of glaucoma,” study co-author Stephen J. Kim, MD, told Healio/OSN.

Researchers evaluated functional outcomes in the inner retina in 20 study eyes that underwent epiretinal membrane surgery and 20 fellow control eyes. The 20 patients were examined preoperatively and at 3, 12, 24, 36, 48 and 60 months postoperatively. Spectral domain OCT was used to analyze retinal nerve fiber layer and ganglion cell-inner plexiform layer (GC-IPL).

At every time point, the mean GC-IPL thickness in study eyes was less than the mean GC-IPL of fellow eyes. For all time points, the overall mean GC-IPL thickness was 68.7 µm in study eyes and 77.4 µm in fellow eyes. Progressive thinning of the GC-IPL in study eyes was observed with statistically significant differences between mean GC-IPL thickness in study eyes and fellow eyes at baseline, 3 months and 5 years (P ≤ .05). Additionally, there was statistically significant thinning of the superotemporal GC-IPL in study eyes compared with fellow eyes at 3 months and 60 months (P < .05).

Study eyes experienced a mean deviation on Humphrey visual field testing that was statistically significantly greater (more negative) compared with fellow eyes at 12 months and 24 months but at no other time point. – by Robert Linnehan

Disclosures: The authors report no relevant financial disclosures.

Eyes that underwent epiretinal membrane surgery experienced progressive thinning of the ganglion cell-inner plexiform layer and worsening Humphrey visual field mean deviation at 5 years’ follow-up, according to a study.

“Our 5-year findings that there is progressive thinning of the inner retina after vitrectomy surgery lend further support to a causal association of vitrectomy surgery with risk of glaucoma,” study co-author Stephen J. Kim, MD, told Healio/OSN.

Researchers evaluated functional outcomes in the inner retina in 20 study eyes that underwent epiretinal membrane surgery and 20 fellow control eyes. The 20 patients were examined preoperatively and at 3, 12, 24, 36, 48 and 60 months postoperatively. Spectral domain OCT was used to analyze retinal nerve fiber layer and ganglion cell-inner plexiform layer (GC-IPL).

At every time point, the mean GC-IPL thickness in study eyes was less than the mean GC-IPL of fellow eyes. For all time points, the overall mean GC-IPL thickness was 68.7 µm in study eyes and 77.4 µm in fellow eyes. Progressive thinning of the GC-IPL in study eyes was observed with statistically significant differences between mean GC-IPL thickness in study eyes and fellow eyes at baseline, 3 months and 5 years (P ≤ .05). Additionally, there was statistically significant thinning of the superotemporal GC-IPL in study eyes compared with fellow eyes at 3 months and 60 months (P < .05).

Study eyes experienced a mean deviation on Humphrey visual field testing that was statistically significantly greater (more negative) compared with fellow eyes at 12 months and 24 months but at no other time point. – by Robert Linnehan

Disclosures: The authors report no relevant financial disclosures.

    Perspective

    This was a prospective interventional cohort study called the Prospective Retinal and Optic Nerve Vitrectomy Evaluation (PROVE) study. Although the title of the manuscript was “Five-year functional outcomes after epiretinal membrane surgery,” the study assessed both functional and anatomic outcomes over a 5-year period, using automated OCT analysis of the ganglion cell-inner plexiform layer (GC-IPL) as well as mean deviation and pattern standard deviation on Humphrey visual fields. The authors designed the study to examine the hypothesized relationship between vitrectomy and secondary open-angle glaucoma.

    Forty eyes of 20 patients undergoing unilateral vitrectomy surgery for idiopathic epiretinal membrane were enrolled. Baseline GC-IPL thickness was thinner at baseline and at 3 months postoperatively in surgical eyes compared with fellow eyes; the authors state these automated measurements were unreliable at baseline and month 3, which may explain this discrepancy. Subsequently, there was progressive thinning of the GC-IPL in surgical eyes compared with fellow eyes, which reached statistical significance at 5 years. In terms of functional outcomes, there was a statistically significant difference in mean deviation between surgical eyes and fellow eyes at 12 and 24 months after surgery, although the authors do not state specifically whether this was driven by the phakic group; there was no difference in pattern standard deviation between surgical and fellow eyes.

    The authors hypothesized that progressive temporal GC-IPL thinning might have been caused at the site of epiretinal membrane peel initiation, although one would think that there would have been a difference in thinning pattern between right and left eyes if that were the case. Another hypothesis was possible increasing IOP leading to progressive GC-IPL thinning, although this was not supported by progressive visual field changes, and IOP was not reported. The authors suggest that progressive GC-IPL thinning may be associated with an increased risk for glaucoma, although only one patient in this cohort required IOP-lowering eye drops postoperatively.

    Overall, this was an ambitious endeavor, and the authors should be commended for the study design. Further studies with larger patient populations will be necessary to more thoroughly evaluate the effects of macular surgery on the inner retinal layers and visual function, and to further elucidate the relationship between vitrectomy and glaucoma.

    • Andre J. Witkin, MD
    • New England Eye Center, Boston

    Disclosures: Witkin reports no relevant financial disclosures.