Face-down positioning to improve outcomes following surgery for macular holes

The eye is responsible for focusing and transforming light stimuli into nerve signals that are processed in the brain for visual perception. The back of the eye is lined by the retina, a layered sheet of nerve cells, and filled with clear gel, known as vitreous gel. The macula is the central area of the retina responsible for perception of fine detail and colour vision. Disorders of the macula typically result in significant visual impairment.

Idiopathic macular hole, an age-related disease, is an important cause of visual loss. The disorder affects at least two per 1000 individuals aged over 40 years. Development of macular holes is believed to result from traction exerted by the vitreous, with separation of the hole edges from the underlying pigment epithelial cells. Macular holes are conventionally managed by surgical removal of the vitreous gel to relieve the tractional forces. Injection of gas (intraocular gas tamponade) into the vitreous cavity is performed with the aim of promoting hole closure.

Following surgery for macular hole, a period of face-down positioning for up to two weeks may be advised, with the aim of improving the likelihood of success by maintaining contact of the gas meniscus with the macula. However, face-down positioning is of unproven benefit, uncomfortable and associated with adverse events including ulnar nerve injury.

We conducted a systematic review of outcomes for individuals with idiopathic macular holes following postoperative face-down positioning. We found three randomised controlled trials (RCTs). Two of the three trials suggested a benefit in holes larger than 400 microns in diameter. None demonstrated evidence of a benefit in smaller holes.

Authors' conclusions: 

There is currently insufficient evidence from which to draw firm conclusions about the impact of postoperative face-down positioning on the outcome of surgery for macular hole. Of three RCTs, two suggested a benefit in larger holes but none demonstrated evidence of a benefit in smaller holes.

CONSORT adherent RCTs and large scale, well designed non-randomised observational studies are needed to determine with confidence the value of this intervention.

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Background: 

Macular holes cause significant loss of central vision. With the aim of improving the outcome of surgery, a variable period of face-down positioning may be advised.

Objectives: 

To evaluate the evidence of the impact of postoperative face-down positioning on the outcome of surgery for macular hole.

Search strategy: 

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2011, Issue 8), MEDLINE (January 1950 to August 2011), EMBASE (January 1980 to August 2011), the International Standard Randomised Controlled Trial Number Register (ISRCTN Register) (http://www.controlled-trials.com), the WHO International Clinical Trials Registry Platform (ICTRP) (http://www.who.int/ictrp/search/en) and ClinicalTrials.gov (http://clinicaltrials.gov). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 29 August 2011.

Selection criteria: 

We included randomised controlled trials (RCTs) in which postoperative face-down positioning was compared to no face-down positioning following surgery for macular holes.

Data collection and analysis: 

Data were collected and analysed independently by two authors.

Main results: 

Three RCTs were identified, A, B and C; one of which was unpublished data. We were unable to conduct a meta-analysis due to study heterogeneity regarding duration of face-down positioning and surgical methods (use of inner limiting peel).
All three studies suggested an overall beneficial effect of posturing in terms of closure of holes: (A: risk ratio (RR) 1.10; 95% confidence interval (CI) 1.00 to 1.20, P = 0.05); B: RR 1.58, CI 1.0 to 2.5, P = 0.01; C: RR 1.03, CI 0.9 to 1.17, P = 0.67).
For holes which were smaller than 400 microns in size, all three studies reported that there was no significant effect of face-down positioning on successful hole closure (A: RR 1.03, CI 0.95 to 1.12; B: RR 1.0, CI 0.68 to 1.46; C: RR 1.03, CI 0.9 to 1.17). However, for holes which were larger than 400 microns in size, both of the studies which examined macular holes of this size agreed on the effectiveness of face-down positioning on hole closure following surgery (A: RR 1.2, CI 1.01 to 1.42, P = 0.04; B: RR 2.27, CI 1.04 to 4.97, P = 0.04).

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