A giant retinal tear is a serious condition involving a full-thickness break in the retina, the eye’s light-sensitive tissue. The retina functions much like film in a camera, capturing images that are sent to the brain. A tear is defined as “giant” when it extends for at least 90 degrees, or one-quarter of the way around the peripheral retina. This type of tear is distinct from smaller retinal breaks and can lead to rapid vision loss, representing a sight-threatening emergency that requires immediate intervention.
Symptoms and Causes
The onset of a giant retinal tear is marked by sudden and severe visual disturbances. Patients report an abrupt increase in floaters, appearing as dark spots or cobwebs moving through their vision. These are often accompanied by flashes of light (photopsia), particularly in the peripheral vision. A defining symptom is a dark shadow or curtain obscuring a large portion of sight, a sign the retina is beginning to detach.
The development of a giant retinal tear is initiated by a posterior vitreous detachment, where the eye’s gel-like vitreous pulls away from the retina. If this separation is forceful or the vitreous is strongly attached, it can create a large, zipper-like rip. Direct trauma to the eye, such as a blunt or penetrating injury, is another cause.
Certain individuals are at higher risk. High myopia, or severe nearsightedness, is a primary risk factor. Genetic disorders affecting connective tissue, like Marfan syndrome and Stickler syndrome, also predispose individuals to retinal tears. A tear can also occur as a complication of previous eye surgery or without any identifiable cause (idiopathic).
Diagnosis and Immediate Management
Confirming a giant retinal tear requires a thorough examination by an ophthalmologist. The primary tool is a dilated fundus examination, where eye drops widen the pupil, allowing the specialist to view the back of the eye. This direct visualization allows for assessment of the tear’s size, location, and any associated retinal detachment.
If the view of the retina is obscured by blood or a dense cataract, a B-scan ultrasonography is employed. This non-invasive procedure uses sound waves to create an image of the eye’s internal structures. It is a reliable method for identifying the tear and any detachment when a direct view is not possible.
A diagnosis of a giant retinal tear is an ophthalmological emergency. The tear’s large size allows fluid to pass through the break and accumulate underneath the retina, leading to rapid retinal detachment. Immediate management focuses on preventing this progression and preparing the patient for urgent surgery.
Surgical Interventions
The primary surgery for repairing a giant retinal tear is a pars plana vitrectomy. A surgeon makes small incisions in the sclera (the white of the eye) to introduce microscopic instruments. The goal is to remove the vitreous gel, which relieves the pulling forces on the retina that caused the tear.
With the vitreous removed, the surgeon flattens the retina into its proper position. A heavy liquid, perfluorocarbon liquid (PFCL), is injected into the eye. This liquid is denser than the fluid under the retina, so it gently pushes the retina back against the eye wall.
Once flattened, the tear is permanently sealed to the underlying tissue using either laser photocoagulation (burns) or cryotherapy (freezing). To hold the retina in place as it heals, a tamponade agent like a gas bubble or silicone oil replaces the PFCL. A scleral buckle, a flexible silicone band, may also be placed around the eyeball for additional support.
Postoperative Care and Prognosis
Following surgery, patients must follow specific instructions for proper healing. If a gas bubble was used as the tamponade agent, strict head positioning is required for days to weeks. The gas bubble is lighter than fluid in the eye and rises, so the head must be positioned so the bubble presses directly against the retinal tear.
Activity is restricted during recovery. Patients must avoid strenuous exercise, heavy lifting, and jarring motions that could disrupt the healing retina. Air travel is forbidden for patients with a gas bubble in their eye, as atmospheric pressure changes can cause the bubble to expand dangerously.
The visual prognosis after repair varies. While surgery successfully reattaches the retina in most cases, final visual acuity depends on whether the macula, the central part of the retina, was detached before the operation. Complications can include proliferative vitreoretinopathy (PVR), which is scar tissue on the retina and the most common cause of surgical failure. Other issues include cataracts and elevated eye pressure, which may require further treatment.