A posterior staphyloma represents an outward bulging or outpouching of the back wall of the eye. It is a structural change most commonly observed in individuals with severe nearsightedness, where the eye’s shape is significantly altered. This localized thinning and stretching of the eye wall can impact vision.
The Link Between High Myopia and Staphyloma Development
The primary factor driving the development of a posterior staphyloma is pathologic myopia, also known as high myopia. In this condition, the eyeball progressively elongates, causing the sclera, the eye’s tough outer layer, to stretch and thin.
As the eye continues to grow longer, certain areas of the sclera become particularly susceptible to expansion, resulting in the characteristic outward bulge. While high myopia is the predominant cause, the exact factors determining why some individuals with significant nearsightedness develop staphylomas and others do not are still being investigated, suggesting a complex interplay of genetic and environmental influences.
Symptoms and Diagnostic Imaging
A posterior staphyloma itself does not cause direct symptoms. Instead, any visual symptoms experienced, such as distorted vision, blind spots, or a gradual decline in sharpness, usually arise from associated complications that develop within the thinned and stretched eye wall.
Ophthalmologists can identify a staphyloma during a dilated fundus examination. Modern diagnostic imaging techniques provide detailed insights into the condition. Optical Coherence Tomography (OCT) uses light waves to create cross-sectional images of the retina and underlying structures, revealing the extent of the outpouching and any related retinal changes.
B-scan ultrasonography employs sound waves to create a two-dimensional image of the eye’s internal structures, which is particularly useful for visualizing the overall shape and depth of the staphyloma. Widefield fundus imaging captures a broad view of the retina, helping to map the full extent of the staphyloma and monitor for peripheral changes.
Associated Vision-Threatening Complications
A posterior staphyloma significantly increases the risk of several vision-threatening complications. The stretching and thinning of the eye wall place considerable stress on the delicate layers of the retina and choroid, leading to various issues that directly impair vision.
One common complication is myopic maculopathy, which involves the thinning and atrophy of the macula, the central part of the retina responsible for sharp, detailed vision. Another serious concern is choroidal neovascularization (CNV), where new, fragile blood vessels grow abnormally beneath the retina. These vessels can leak fluid or bleed, causing rapid and severe vision loss if left untreated.
Macular holes, which are small breaks in the center of the macula, and foveoschisis, a splitting of the retinal layers, can also develop due to the stretching forces. These conditions disrupt the normal architecture of the central retina, leading to distorted or missing central vision.
Furthermore, the altered shape of the eye in a staphyloma can increase the likelihood of a retinal detachment, where the retina pulls away from its underlying support layers, potentially causing extensive vision loss across the visual field.
Treatment and Monitoring Strategies
There is currently no medical or surgical treatment available to reverse or “fix” the posterior staphyloma itself. The primary focus of management is therefore on diligent monitoring for the development of associated complications and promptly treating those complications if they arise. Regular, lifelong follow-up appointments with a retina specialist are recommended.
These monitoring visits involve repeated diagnostic imaging, such as OCT scans, to track any changes in the retinal and choroidal layers. This allows clinicians to detect early signs of complications like choroidal neovascularization, macular holes, or retinal detachment.
Treatment strategies are directed at managing the specific complications. For example, choroidal neovascularization is treated with anti-VEGF injections, medications delivered directly into the eye to inhibit abnormal blood vessel growth and leakage. Macular holes or retinal detachments require vitreoretinal surgery to repair the retinal structure and preserve vision. The overall goal is to proactively manage these secondary conditions, aiming to preserve useful vision for as long as possible.