Retinochoroidal coloboma is an eye abnormality that occurs before birth. It is characterized by missing pieces of tissue in both the retina (the light-sensitive tissue lining the back of the eye) and choroid (the blood vessel layer under the retina). In many cases, retinochoroidal coloboma does not cause symptoms. However, complications such as retinal detachment may occur at any age. Other possible complications include loss of visual clarity or distorted vision; cataract; and abnormal blood vessel growth in the choroid (choroidal neovascularization). Retinochoroidal coloboma can involve one or both eyes, and may occur alone or in association with other birth defects. It can be inherited or can occur sporadically.
There is no cure for retinochoroidal coloboma. Treatment varies depending on the conditions or complications that present in each individual. In some instances, retinochoroidal colobomas do not cause any symptoms and treatment is not necessary. Complications that commonly occur include:
- Tear or detachment of the retina (retinal detachment)
- Growth of new blood vessels beneath the retina that disrupt vision (choroidal neovascularization)
- Clouding of the lens (cataracts)
- Increased eye pressure leading to damage to the optic nerve (glaucoma)
Treatment of retinal detachment depends on the severity of the condition. For smaller retina tears, laser surgery (photocoagulation) or freezing treatment (cryopexy) may be utilized to induce a scar that helps to secure the retina to the eye wall. For larger tears or a detachment, surgery is typically needed to place the retina back into its proper position. Options may include: scleral buckle, pneumatic retinopexy, or vitrectomy. Surgical treatment of retinal detachment in individuals with retinochoroidal coloboma can be challenging and has variable success.
Treatment for choroidal neovascularization may include administration of medications that can block the abnormal growth of blood vessels (anti-VEGF treatment), thermal laser treatment to destroy abnormal blood vessels, and photodynamic therapy to damage unwanted blood vessels.
Cataracts are usually treated surgically via a technique called phacoemulsification. In this procedure, an instrument is used to break up and remove the cloudy lens. A lens implant is then placed to allow light to pass through and focus properly on the retina.
Glaucoma treatment varies and may include medication or surgery. Various surgical techniques can be utilized including: laser trabeculoplasty, laser iridotomy, peripheral iridectomy, trabeculectomy, and aqueous shunt surgery. The goal of surgery in glaucoma is to reduce the pressure on the eye.
The American Academy of Ophthalmology provides information and videos on treatment for retinal detachment, choroidal neovascularization, cataracts, and glaucoma.
The visual outlook (prognosis) for people with colobomas varies greatly and depends on the severity and extent of involvement. In many cases, retinochoroidal colobomas do not cause any symptoms. However, complications are not uncommon and often cause decreased visual acuity or distorted vision, especially when they extend to the macula or optic disc. A complication can develop at any age throughout life. The most common complications are retinal detachment (in up to 43% of cases) and choroidal neovascularization (abnormal growth of new blood vessels in the choroid).
Visual acuity has been found to be worse in people who have associated structural abnormalities (particularly retrobulbar cyst) or retinal detachment. Colobomas without microcornea (abnormally small cornea) or microphthalmia (abnormally small eyes) reportedly have the best visual prognosis, while complex colobomas associated with microphthalmia and retrobulbar cysts have the worst visual prognosis.
Early recognition and treatment of any associated complications, including cataracts, glaucoma, and retinal detachment, is important.