MACULAR HOLE

SIGNS AND SYMPTOMS
Idiopathic or senile macular holes are typically encountered in patients older than 60, and slightly more often in women than in men. Presenting symptoms include decreased central acuity, a central scotoma and/or metamorphopsia.

Macular holes develop in stages, including: foveal detachments (stage I), partial-thickness holes (stage II), and full-thickness holes (stage III). A stage IV macular hole is an advanced full-thickness hole, with vitreous separation from the optic disc and macula. Depending on the stage, vision may range from 20/20 to <20/400; however, in full-thickness macular holes, the acuity is generally 20/80 to 20/200.

Patients usually report a rather abrupt loss of central vision. A full-thickness macular hole clinically appears as a round, brick-colored lesion in the center of the macula, usually one-third to two-thirds of a disc diameter.

The surrounding retinal tissue appears gray and elevated, and often there are small yellow deposits within the hole, reminiscent of drusen. Foveal detachments and partial-thickness holes do not appear red, but rather present as a loss of the foveolar depression with the development of a central yellow spot or ring. Stage II holes are accompanied by a red, crescent-shaped retinal break at the lesion's edge. Fluorescein angiography reveals an RPE "window defect" with early-stage hyperfluorescence.

PATHOPHYSIOLOGY
Controversy surrounds the etiology of idiopathic macular holes. Diverse mechanisms have been proposed, including systemic vascular disease, hormonal variations, cystic retinal degeneration, anterior vitreoretinal traction, and tangential vitreoretinal tractional forces.

Currently, the most widely held theory proposes that pre-foveal vitreal shrinkage induces tangential traction on the fovea, eventually promoting hole formation. As contraction ensues, the tangential tugging at the fovea induces a separation of the sensory retina from the underlying RPE. The foveal retina, without a firm attachment to the RPE, suffers a compromised nutrient supply and loses its ability to eliminate waste.

Ultimately, the sensory retina atrophies, forming a break and progressing to a full-thickness hole. Macular holes may also result from chronic macular edema, solar retinopathy and blunt ocular trauma.

MANAGEMENT
In the past, the only management for macular holes was patient education, periodic observation in the affected and fellow eye, and the use of protective eyewear.

More recently, research has shown some benefit to surgical excision of the macular vitreoretinal adhesions in eyes at risk for full-thickness holes. The procedure involves pars plana vitrectomy, excision of the attached cortical vitreous and gas/fluid exchange. Growth factors such as transforming growth factor-b2 have been used to induce regeneration of the macular tissue. This procedure has achieved moderate success. Candidates for surgical intervention must have 20/50 visual acuity or worse, and a stage III or IV macular hole in at least one eye.

For cases that do not lend themselves to surgical intervention, consider low vision services.

CLINICAL PEARLS

Idiopathic macular holes affect the elderly. The astute clinician must consider this entity in the differential diagnosis of older patients who present with reduced visual acuity and a seemingly unremarkable examination.

The best way to observe the macula involves a contact fundus lens, be it a standard Goldmann three-mirror goniolens or any of the newer, more compact funduscopy lenses.

For suspected macular holes that appear equivocal or do not lend themselves to observation, consider the Watzke-Allen test. A vertical beam of light is presented to the fovea, using a Maddox rod, slit lamp beam with a fundus lens or a direct ophthalmoscope. Ask the patient if the line is uniform or broken in the center-patients with macular compromise report a broken line.

Macular holes are rarely, if ever, self-limiting. It is your obligation to educate the patient about the nature of the condition, and make the appropriate referrals necessary to ensure maximal visual function.

Other important facts:

50 percent of Stage I holes will progress to Stage II or worse.

70 percent of Stage II holes will progress to Stage III.

Retinal consultation is advisable in Stage I and II holes.

Vitrectomy may be helpful in Stage I holes to prevent progression to Stage II; it may also improve vision.

Vitrectomy is helpful in Stage II holes to preserve vision.