Macular hole, epiretinal membrane
Epiretinal membrane is a thin film of fibrous tissue that sometimes forms on the surface of the retina in response to age-related changes in the vitreous, or occasionally, because of inflammation, diabetes or trauma. The membrane can sometimes contract like scar tissue, which in this case is called “macular pucker” – which changes the shape of the surface of the part of the retina which confers the sharpest vision (the macula) and distorts vision even further.
Macular pucker can progress, tearing what’s called a “macular hole”, in which the fluid that occupies the space between the shrinking vitreous and the retina can enter through that hole, into the macula, causing blurring and irritation. A number of other conditions can increase the chances of developing a macular hole, including high myopia (short sightedness), diabetic retinopathy, eye injury or trauma, and retinal detachments.
Macular holes tend to affect your central, rather than peripheral, vision, and it can impair your ability to read or do “close work” (such as sewing or using a smartphone). The visual disturbances often take time to manifest, but people tend to notice that straight lines (such as windows or traffic lights) appear bent or wavy, although sometimes black spots and blank holes can be present too. One way of testing for macular hole is to use an Amsler grid (below), in which patients look with each eye separately at the small dot in the center of the grid. Patients with macular disease might see broken or wavy lines.
Amsler grid – on screen or on paper (A), or as seen by people with macular disease (B).