The effectiveness of surgery for treating lamellar macular holes

Why is this question important?
Lamellar macular holes are small partial-thickness defects affecting the centre of the retina, called the macula. The retina is the layer at the back of the eye that detects light, and the macula is essential for detailed vision. It has been suggested that surgery can prevent vision loss (or improve vision) in people with lamellar macular holes, but there is no current consensus. We reviewed published research to determine whether surgery improves vision for people with a lamellar macular hole.

How did we identify and evaluate the evidence?
First, we searched for randomised controlled studies (clinical studies where people are randomly put into one of two or more treatment groups), because these studies provide the most robust evidence about the effects of treatment. We then planned to compare the results, and summarise the evidence from the studies. Finally, we then aimed to rate our confidence in the evidence, based on factors such as study methods and sizes, and how similar the findings of the different studies were.

What did we find?
We found one study that involved a total of 36 people with a diagnosis of a lamellar macular hole. This study showed that people who underwent surgery may achieve better vision six months after their surgery compared with people who were observed without receiving surgery. However, limitations in the study design and its small size means that our confidence in the evidence was low.

What does this mean?
It remains unclear whether surgery is effective for people with lamellar macular holes. Further research is required.

How up-to-date is this review?
The evidence in this Cochrane Review is current to 20 July 2021.

Authors' conclusions: 

The included single trial demonstrated improvements in visual and anatomical outcome measures for participants with a LMH who underwent surgery compared with observation only. Therefore, we can conclude that participants who undergo surgery may achieve superior post-operative best corrected visual acuity and anatomical outcomes compared with observation only. However, the results of a single and small RCT provides limited evidence to support or refute surgery as an effective management option for LMHs. Future RCTs with a larger number of participants and with fewer methodological limitations and biases are necessary to inform future clinical practice.

Read the full abstract...
Background: 

Lamellar macular holes (LMHs) are small, partial-thickness defects of the macula defined by characteristic features on optical coherence tomography (OCT), including a newly recognised type of epiretinal membrane termed ‘epiretinal proliferation’. There may be a rationale to recommend surgery for individuals with LMHs, particularly those with functional or anatomical deterioration, or poor baseline vision causing significant disability, to stabilise the LMH and prevent further visual deterioration; however, there is currently no evidence-based consensus.

Objectives: 

To assess the effect of surgical interventions on post-operative visual and anatomical outcomes in people with a confirmed LMH.

Search strategy: 

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE Ovid, Embase Ovid, Scopus SciVerse, ISRCTN registry, US National Institutes of Health Ongoing Trials Register, ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We also searched reference lists of included trials to identify other eligible trials which our search strategy may have missed. The date of the search was 20 July 2021.

Selection criteria: 

We included randomised controlled trials (RCTs) involving participants with a confirmed LMH diagnosis which reported one or more surgical intervention(s), alone or in combination, in at least one arm of the RCT.

Data collection and analysis: 

We used standard methods as expected by Cochrane. Two study authors independently extracted data and assessed the risk of bias for included trials. Trial authors were contacted for further information and clarification.

Main results: 

A single RCT was eligible for inclusion. Thirty-six participants were randomised in a 2:1 ratio; 24 were allocated to undergo surgery (pars plana vitrectomy, peeling of the epiretial proliferation followed by fovea-sparing removal of the internal limiting membrane) and 12 (10 following two participant dropouts) to observation.

Overall, the certainty of the evidence was low for all outcomes due to selection and detection bias, and the low number of participants enrolled in the study which may affect the accuracy of results and reliability of conclusions.

At six-month follow-up, change in vision was better in the surgery group (-0.27 logMAR improvement) than observation (0.02 worsening) (mean difference (MD): -0.29 logMAR, 95% confidence intervals (CI): -0.33 to -0.25). Central retinal thickness increased in the surgery group over 6 months 126 μm increase) compared with observation group (decrease by 11μm) (MD: 137 μm, 95% CI: 125.87 μm to 148.13 μm). Finally, at six-month follow-up, retinal sensitivity was better in the surgery group (3.03 dB increase) compared with the observation group (0.06 dB decrease) (MD: 3.09 dB , 95% CI: 2.07 to 4.11 dB).

Vision-related quality of life and metamorphopsia were not reported. No adverse outcomes or complications were reported in the study, however, authors could not provide information on whether any individuals developed deterioration in vision of 0.2 logMAR or worse.