Degenerative myopia is a severe, progressive form of nearsightedness where the eyeball continues to elongate over time, stretching and damaging the structures at the back of the eye. Unlike ordinary myopia, which can be fully corrected with glasses or contacts, degenerative myopia causes permanent structural changes that can lead to irreversible vision loss. It is the second leading cause of visual disability or blindness globally, and it disproportionately affects younger people compared to other blinding conditions.
How It Differs From Regular Myopia
Standard myopia means your eyeball is slightly longer than normal, so light focuses in front of the retina instead of on it. Corrective lenses fix this easily. Degenerative myopia, also called pathological myopia, involves excessive axial elongation that goes well beyond simple blurriness. The eye keeps growing longer, and as it does, the retina, the blood vessel layer beneath it, and the structural membrane between them all get stretched thin and begin to break down.
The condition is often equated with high myopia, typically defined as a prescription of negative 6.00 diopters or stronger, or an eye length greater than 26 millimeters (a normal eye is roughly 23 to 24 mm). But the defining feature isn’t the prescription number itself. It’s the presence of structural damage: thinning and atrophy of the tissue layers at the back of the eye, outward bulging of the eye wall (called a posterior staphyloma), and specific lesions in the macula, the part of the retina responsible for sharp central vision.
What Happens Inside the Eye
As the eyeball elongates, the tissues lining the back of the eye are forced to cover a larger surface area than they were designed for. This stretching produces a cascade of damage that clinicians classify into distinct types of lesions. Early on, the retinal pigment layer thins enough that the blood vessels underneath become visible, a change called tessellation. Over time, patches of the nourishing blood vessel layer (the choroid) and the retinal pigment layer waste away entirely, leaving areas of atrophy that can no longer support healthy vision.
Two hallmark findings are particularly telling. Lacquer cracks are literal breaks in Bruch’s membrane, the thin barrier between the retina and its blood supply. These cracks allow abnormal blood vessels to grow through into the retina, a complication called choroidal neovascularization. When those abnormal vessels eventually scar over and stop leaking, they leave behind a pigmented grayish-white mark known as a Fuchs’ spot.
The posterior staphyloma, an outward bulge in the eye wall near the macula, is one of the most significant structural changes. It distorts the retinal surface and creates traction that can pull retinal layers apart (retinoschisis) or detach the retina from the tissue beneath it. People with high myopia face a retinal detachment risk five to six times greater than those with mild myopia.
Causes: Genetics and Environment
Degenerative myopia has a strong genetic component. Researchers have identified 26 distinct chromosomal regions linked to myopia through family studies, scattered across nearly every chromosome. Several genes play roles in the structural integrity of the eye wall. Variants in the COL1A1 gene, which governs collagen assembly in connective tissues, are associated with Stickler syndrome, a hereditary disorder that frequently involves high myopia. Other genes influence eye elongation more directly: mutations in SLC39A5, for example, have been shown to play a specific role in how the eye grows longer. The PAX6 gene, critical to eye development, and TGFB1, involved in tissue growth regulation, have also been linked to high myopia susceptibility.
Environmental factors compound genetic risk. Prolonged close-up work and limited time outdoors during childhood are well-established contributors to myopia development in general, and they likely accelerate progression in those genetically predisposed to the degenerative form. Global projections estimate that by 2050, half the world’s population will be myopic, with 10% reaching high myopia, making the pool of people at risk for degenerative complications substantially larger than it is today.
Vision-Threatening Complications
The most acute threat to vision in degenerative myopia is choroidal neovascularization, where abnormal blood vessels grow through the cracks in Bruch’s membrane and leak fluid or blood into the macula. This occurs in roughly 4% to 10% of people with pathological myopia, and without treatment, it causes rapid central vision loss. Even after successful treatment, about one in four eyes will experience a recurrence within roughly 16 months.
Other serious complications include macular holes (full-thickness breaks in the central retina), macular detachment caused by traction from the staphyloma, and progressive atrophy of the macula that gradually erodes central vision over years. Pathological myopia is the leading cause of low vision and blindness in about 7% of the European population and 12% to 27% of Asian populations, making it a significant public health concern worldwide.
How It’s Monitored
Optical coherence tomography, or OCT, has become the essential tool for tracking degenerative myopia. It produces detailed cross-sectional images of the retina’s individual layers, revealing changes that are invisible during a standard eye exam. OCT can detect early splitting of retinal layers, subtle fluid accumulation, and thinning of the choroid long before a person notices any symptoms. Because some of these changes develop silently, periodic OCT scans are recommended even for patients who feel their vision is stable.
Wide-field fundus imaging complements OCT by capturing a broad view of the retina in a single photograph, making it easier to document and compare the extent of atrophy, staphyloma, and other changes over time. Together, these tools allow eye specialists to catch complications early, when treatment is most effective.
Treatment Options
There is no cure for degenerative myopia, and no treatment can reverse the structural stretching of the eye. Management focuses on treating complications as they arise and, in some cases, trying to slow further elongation.
Injections for Abnormal Blood Vessel Growth
When choroidal neovascularization develops, the standard treatment is injections of medication directly into the eye that block the growth signal driving the abnormal vessels. These injections shrink the leaking vessels and reduce fluid in the macula. Most patients see meaningful visual improvement within the first year. The treatment burden is relatively low compared to similar injections used for age-related macular degeneration: patients with myopic neovascularization typically need an average of about 2.5 injections over two years. If the abnormal vessels recur, retreatment works well. Studies show that people who experience a recurrence and are treated promptly end up with the same visual outcome as those who don’t recur, needing only about two additional injections on average.
Scleral Reinforcement Surgery
For eyes that are rapidly elongating or developing traction-related complications like retinoschisis or macular detachment, a procedure called posterior scleral reinforcement aims to mechanically stabilize the back of the eye. A piece of donor or synthetic tissue is placed behind the eye to support the thinned wall, limiting further stretching. In one study of eyes averaging nearly 30 mm in length (far beyond normal), axial length showed a statistically significant reduction at six months after surgery, and that stabilization held through 18 months of follow-up. The procedure also appeared to thicken the choroid, the blood vessel layer that nourishes the retina. When combined with anti-growth-factor injections, scleral reinforcement reduced the expansion of surrounding atrophy by over 94% at two years compared to injections alone.
Living With Degenerative Myopia
Because the condition is progressive and lifelong, consistent monitoring is more important than any single treatment. Most vision loss from degenerative myopia comes not from the nearsightedness itself but from the complications that develop over years or decades. Catching choroidal neovascularization early, before significant scarring occurs, makes the difference between preserving functional vision and losing it permanently. Regular dilated eye exams with OCT imaging, typically at least annually for anyone with high myopia and more frequently if complications are present, form the backbone of long-term management.
Low vision aids, including magnifying devices and screen readers, can help people whose central vision has already been affected maintain independence in daily tasks. Because degenerative myopia tends to strike during working-age years rather than in old age, the functional and economic impact of vision loss can be especially significant.