Vitrectomy for idiopathic macular hole

Background
A macular hole is an opening in the retina (the layer at the back of the eye that is sensitive to light) that develops at the fovea (the part of the eye that is responsible for sharp vision) and causes a small dark spot in the central vision, often preventing those with the condition from recognising very small objects, and particularly from reading ordinary print. Macular holes can be seen in people with highly myopic eyes (who cannot see clearly in the distance) or following ocular trauma, but in the great majority of cases the cause is unknown (idiopathic).

Pars plana vitrectomy has been used for more than a decade to treat full-thickness macular holes, which if left untreated cause a blind spot in central vision that only rarely improve naturally. Vitrectomy is a surgical technique involving the removal of the vitreous body (the clear gel that fills the eye). The surgeon inserts thin tubes called cannulas into the eyes through scleral (white part of the eye) incisions or incision of the eye wall to relieve traction exerted by the vitreous to the central retina and close the hole. The objective of this review was to examine the effects on visual acuity of vitrectomy for idiopathic macular hole.

Study characteristics
We included three studies, published between 1996 and 2004 and conducted in the USA and the UK, including 270 eyes in analyses, comparing vitrectomy and observation after 6 or 12 months. The evidence is current as of March 2015.

Key results
Vitrectomy improved visual acuity in participants with macular hole by about 1.5 lines of a standard distance acuity chart. Macular hole closure was much more likely with vitrectomy compared to observation, with mean closure rates of 76% versus 11%, respectively.

Cataract surgery was common in operated eyes. In the largest study, retinal detachment occurred in the months following vitrectomy in about 5% of cases.

Quality of the evidence
The evidence was of moderate quality, as the visual acuity measurement was unmasked.

Conclusion
Vitrectomy is effective in improving visual acuity, resulting in a moderate visual gain, and in achieving hole closure in people with macular hole. However, as vitrectomy technology has improved since the included trials were conducted, with use of a smaller incision and outpatient care, the results of this review may not apply to modern surgery.

Authors' conclusions: 

Vitrectomy is effective in improving visual acuity, resulting in a moderate visual gain, and in achieving hole closure in people with macular hole. However, these results may not apply to modern surgery due to technological improvements in vitrectomy techniques.

Read the full abstract...
Background: 

A macular hole is an anatomic opening in the retina that develops at the fovea. Macular holes can be seen in highly myopic eyes or following ocular trauma, but the great majority are idiopathic. Pars plana vitrectomy was introduced to treat full-thickness macular holes, which if left untreated have a poor prognosis since spontaneous closure and visual recovery are rare.

Vitrectomy is a surgical technique involving the removal of the vitreous body that fills the eye. The surgeon inserts thin cannulas into the eyes through scleral incisions to relieve traction exerted by the vitreous or epiretinal membranes to the central retina and to induce glial tissue to bridge and close the hole.

Objectives: 

The primary objective of this review was to examine the effects of vitrectomy for idiopathic macular hole on visual acuity. A secondary objective was to investigate anatomic effects on hole closure and other dimensions of visual function, as well as to report on adverse effects recorded in included studies.

Search strategy: 

We searched the Cochrane Eyes and Vision Group Trials Register (4 March 2015), the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 2), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to March 2015), EMBASE (January 1980 to March 2015), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to March 2015), the Web of Science Conference Proceedings Citation Index-Science (CPCI-S) (January 1980 to March 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 4 March 2015.

Selection criteria: 

We included randomised controlled trials comparing vitrectomy (with or without internal limiting membrane peeling) to no treatment (that is observation) for macular holes.

Data collection and analysis: 

We used standard methodological procedures expected by Cochrane. Two review authors independently extracted the data. We estimated best corrected visual acuity and macular hole closure at 6 to 12 months of follow-up.

Main results: 

Three studies provided data on the comparison between vitrectomy and observation in eyes with macular hole and visual acuity less than 20/50. Two studies, conducted in the USA and published in 1996 and 1997, used a similar protocol and included participants with stage II macular hole (42 eyes randomised, 36 analysed, number of participants not reported) or participants with stage III/IV hole (129 eyes of 120 participants, 115 eyes in analyses). The third study, conducted in the UK and published in 2004, included 185 eyes of 174 participants with full-thickness macular hole (41 eyes with stage II holes and 74 eyes with stage III/IV holes in analyses). Studies were of good quality for randomisation and allocation concealment, whereas visual acuity measurement was unmasked.

At 6 to 12 months, visual acuity was improved by about 1.5 Snellen lines (-0.16 logMAR, 95% confidence intervals -0.23 to -0.09 logMAR, 270 eyes, moderate-quality evidence). The chances of macular hole closure at 6 to 12 months were greatly increased using vitrectomy, yielding an odds ratio of 31.4 (95% confidence intervals 14.9 to 66.3, 265 eyes, high-quality evidence; raw sum data: 76% vitrectomy, 11% observation). Vitrectomy was beneficial both in smaller (stage II) and in larger (stage III/IV) macular holes.

The largest study reported that cataract surgery was needed in about half of cases at two years after operation and that retinal detachment occurred in about 5% of operated eyes.

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