• Synonyms: macular cyst, retinal hole, retinal perforation
• A macular hole is a full-thickness defect of retinal tissue.
• It runs from the internal limiting membrane to the outer segment of the photoreceptor layer. It involves the fovea, so affects central visual acuity (VA).

Etiology

• Usually idiopathic (<10% have a history of trauma). The most widely accepted theory suggests that age-related focal shrinkage of the prefoveolar vitreous cortex causes traction on the foveal area, leading to foveal detachment and subsequent macular hole formation.
• Other risk factors include cystoid macular edema, retinal detachment, laser injury, hypertension, very high myopia and diabetic retinopathy.

Ophthalmic features

• It may rarely be an incidental finding. Symptoms appear gradually over days/weeks:
• Distorted vision as well as visual loss.
• Visual acuity (VA) will depend on the site of the hole.
• Look for a tiny well-defined 'punched out' area of the macula which can be hard to detect. There may be yellow-white deposits at the base with a grey margin around it representing oedema.
• Slit Lamp Examinattion will show 'a round excavation with well-defined borders' interrupting the beam of the slit lamp.
• Most patients also have a semi-translucent tissue over the hole, which may be surrounded by a grey halo caused by detachment of the retina.
• Gass Biomicroscopic Classification
• Stage 1a Seen as a yellow spot. This is not specific for macular hole - can be associated with central serous chorioretinopathy, cystoid macular oedema, and solar maculopathy.
• Stage 1b Occult hole: doughnut-shaped yellow ring (approximately 200-300 μm) centred on the foveola. Approximately 50% of holes progress to stage 2.
• Stage 2 Full thickness macular hole (<400 μm). Prefoveolar cortex usually separates eccentrically creating a semi-transparent opacity, often larger than the hole, and the yellow ring disappears. These generally progress to stage 3.
• Stage 3 Holes >400 μm associated with partial vitreomacular separation.
• Stage 4 Complete vitreous separation from the entire macula and optic disc

Investigations

• Diagnosis is usually made clinically; however, the following may be useful:
• Ocular coherence tomography (OCT) provides high-resolution cross-sectional imaging of the retina and is useful in predicting prognosis.
• Fluorescein angiography (FA), although not usually necessary, may be useful in differentiating macular holes from cystoid macular oedema and choroidal neovascularisation (CNV).
• It typically shows a window defect early in the angiogram that does not expand with time, and there is no leakage or accumulation of dye.
• There may be Amsler grid abnormalities. However, plotting small central scotomas is often difficult.

Treatment

• About 50% of stage 1 holes resolve spontaneously, but almost all stage 2 (and above) progress without surgery.
• The chosen surgery depends on the staging of the hole. Surgical closure of the hole is considered up until stage 3 or 4 associated with a visual acuity (VA) of 6/18 or worse. If the macular hole has been present for 1-3 years, then surgery is likely to work. If it has been present for 5 years or longer, then results may be more variable.
• Vitrectomy may relieve traction on the edge of the hole. The vitreous ± internal limiting membrane are removed and a long-acting gas bubble is introduced to tamponade the macula back into position. Short periods of postoperative prone posturing are being used in some centres in selected patients to aid surgical procedures associated with intraocular gas tamponade to achieve macular hole closure and there is increasing evidence to support its use.
• Vitrectomy (with fluid-gas exchange for stage 2, 3, and 4 holes) improves vision compared with conservative treatment. Series of patients have been variously reported with hole closure rates of 73-95%. Most patients' VA improves by two lines of the Snellen chart.
• Success is also possible if the hole is long-standing (6 months-2 years) or if the patient is aged >80 years.
• Occasionally more than one operation is required to close the hole.
• Standard vitrectomy with internal limiting membrane (ILM) maculorrhexis (peeling) has been performed in patients with stage 3 or 4 idiopathic macular holes. The retina is massaged to approximate the edges of the hole as closely as possible. This technique gives a good anatomical and functional result.
• For those patients who have a condition that precludes surgery, visual rehabilitation may be the only option with, for example, referral to low visual aids clinics if needed.