The center of the retina is called the macula, which is responsible for sharp central vision. A healthy retina is firmly affixed to the back wall of the eye, and the vitreous is a jelly-like substance that fills the eye in front of the retina. As a person ages, the vitreous may form small clumps or strands, and the vitreous may shrink in volume. A minor result of these changes is the occasional ‘floater.’ The vitreous may also exert horizontal forces (somewhat akin to rubbing your hands) on the retina leading to the formation of a ‘stretch’ hole in the macula.
For most patients, a macular hole causes a slight visual distortion or reduction, but a hole that penetrates through the entire retina may cause significant vision loss. In either case, a retina surgeon will perform vitrectomy surgery to remove the thickening vitreous and replace it with a gas bubble that eventually fills with natural fluids. The surgeon may also manipulate retinal membranes to reduce the horizontal pressure.
Surgery is generally effective in closing the hole and produces significant vision improvements in just over 50% of patients. However, an untreated macular hole can lead to permanent legal blindness, so surgery is usually warranted.
The animation below provides more information on macular holes.