Vitreomacular traction (VMT) is an eye condition that can impact a person’s central vision. It develops when the vitreous, a gel-like substance filling the eye, exerts an abnormal pulling force on the macula, a small but important part of the retina. This pulling can lead to various visual disturbances, affecting the sharpness and clarity of what one sees directly ahead.
Understanding Vitreomacular Traction
The vitreous humor is a clear, gel-like substance that fills the large space between the lens and the retina, making up about 80% of the eye’s volume. Its primary functions include maintaining the eye’s spherical shape, allowing light to pass unobstructed to the retina for clear vision, and acting as a shock absorber. This gel is mostly water, with collagen, proteins, and sugars giving it its consistency.
The macula is a specialized, yellowish area located at the center of the retina at the back of the eye. It is densely packed with photoreceptor cells and is responsible for sharp, detailed central vision, including the ability to see colors and fine print. The macula normally lies flat against the back of the eye, similar to the film in a camera.
As a person ages, the vitreous gel naturally liquefies and shrinks. This process often leads to a complete separation of the vitreous from the retina, known as a posterior vitreous detachment (PVD), a normal part of aging. However, in some individuals, the vitreous does not fully detach and remains abnormally attached to the macula. This persistent attachment causes the shrinking vitreous to pull on the macula, creating traction that can distort its normal shape. This pulling force, if strong enough, can damage the macula and result in vision impairment.
Recognizing Symptoms and Diagnosis
Vitreomacular traction can manifest through several visual symptoms. Common symptoms include blurred central vision. Distorted vision, known as metamorphopsia, occurs when straight lines appear wavy, bent, or broken. People might also notice objects appearing smaller than their actual size (micropsia) or see flashes of light (photopsia). In some cases, a central blind spot, or scotoma, can develop, especially if the macula swells or a hole forms.
Diagnosing VMT involves a comprehensive eye examination performed by an ophthalmologist. This includes a visual acuity test to assess the sharpness of vision.
The primary diagnostic tool used to confirm VMT is Optical Coherence Tomography (OCT). OCT is a non-invasive imaging technique that uses light waves to create detailed, cross-sectional images of the retina’s layers. This allows the ophthalmologist to visualize the vitreous pulling on the macula, assess the extent of the traction, and identify any associated structural changes like foveal distortion, intraretinal cysts, or fluid accumulation. OCT can also differentiate between vitreomacular adhesion (where the vitreous is attached but not causing distortion) and vitreomacular traction (where distortion is present).
In some instances, a dilated fundus exam allows the doctor to directly view the retina and vitreous. Fluorescein angiography might also be used to evaluate blood circulation in the retina and detect macular swelling.
Managing Vitreomacular Traction
Managing vitreomacular traction involves several approaches, depending on the severity of symptoms and the extent of macular distortion. For individuals with mild VMT and minimal or no impact on their vision, observation is a common initial strategy. This “wait-and-see” approach is based on the understanding that some cases of VMT can resolve spontaneously as the vitreous continues to detach. Regular monitoring with follow-up eye exams and at-home vision checks using an Amsler grid are recommended to track any changes.
Pharmacological treatment offers a less invasive option for selected patients. Ocriplasmin, marketed under the brand name Jetrea, is a medication administered as a single injection into the eye. This recombinant protease works by breaking down specific proteins that form the adhesion between the vitreous and the macula. By dissolving these attachments, ocriplasmin aims to release the traction and allow the macula to return to its normal position. It is generally considered for cases with focal vitreous attachment and without certain other macular conditions.
For more severe or persistent VMT, particularly if vision is significantly impaired or complications like a macular hole develop, surgical intervention may be recommended. Vitrectomy is the standard surgical procedure for VMT. During this operation, tiny instruments are inserted into the eye to carefully remove the vitreous gel, thereby relieving the pulling force on the macula. The surgeon may also peel any scar tissue that might be contributing to macular distortion. After the vitreous is removed, it is replaced with a saline solution to help support the retina during healing.
The choice of treatment is individualized and influenced by several factors. These include the severity of symptoms, the degree of vision loss, the presence of complications like macular holes or swelling, and the specific characteristics of the vitreous traction as visualized on OCT scans. The patient’s overall health and their ability to comply with post-procedure instructions also play a role in determining the most suitable management plan.