A stage IV macular hole is an advanced full-thickness hole, with vitreous separation from the optic disc and macula. Patients usually report a rather abrupt loss of central vision. 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.
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. 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.