Fundoscopy is examination of the retina. This is done by instilling dilating drops in the eye. The pupil dilates and the retina can be examined by direct or indirect ophthalmoscopy.
The retina is the light sensitive layer at the back of the eye. When this layer separates from the underlying choroid, a retinal detachment is said to occur. This happens due to retinal tears, holes or lattices. The patient experiences flashes of light or floaters in his vision followed by a black “curtain dropping” visual experience.
Retinal detachment requires immediate surgery. Vitrectomy is done to remove the vitreous inside the eye. The subretinal fluid is drained and oil or gas is injected to reposition the retina. After this procedure the patient is required to maintain a certain head position for 2 weeks to ensure complete retinal attachment.
Vitreous hemorrhage refers to bleeding inside the eye, within the vitreous cavity. This occurs due to advanced diabetic retinopathy, proliferative vein occlusions, retinal tears, acute posterior vitreous detachment and trauma. The cause of vitreous hemorrhage will determine the treatment. Most cases can be treated with anti-VEGF injections but some require immediate surgery.
Floaters are spots in your vision. They can look like cobwebs, rings, lines, dots, circles. These are mostly particles in the vitreous casting a shadow on the retina. Most of the time floaters are physiological. Floaters can also occur when bleeding occurs inside the eye and when inflammation occurs in a condition called vitritis. This is why a person with sudden onset of floaters needs a complete retinal examination.
Cataract is a clouding of the clear lens of the eye. This causes blurring of vision and in advanced cases complete loss of vision. Surgery is required to remove cataracts. The latest procedure is called phacoemulsification in which a fine instrument is introduced into the eye through a very small opening and the lens is eaten up. This is then replaced with an intraocular lens of your power. The intraocular lens can be unifocal or multifocal. Unifocal lenses ensure good distance vision but you would require glasses for reading. Multifocal lenses remove the dependency on glasses completely. Phacoemulsification has best results when the cataract is not too advanced. Early surgery is advocated unlike in the early days where we would wait for the cataract to “ripen”.
Diabetic retinopathy is a complication of diabetes that affects the retina. This occurs in patients with long standing diabetes and progresses with time if not treated. In this condition, blood supply to the retina slowly comes down. As a result, new blood vessels grow on the retina which are fragile and break causing bleeds or vitreous hemorrhage. This eventually leads to tractional retinal detachment and complete loss of vision.
Diabetic Macular Edema or swelling in the central part of the retina also occurs causing early blurring of vision. This can be treated with injections and laser. A complete kidney function test is advised for patients with diabetic retinopathy as retinopathy and nephropathy often occur together.
Laser surgery for PDR or proliferative diabetic retinopathy is done to the periphery of the retina, avoiding the central macula. A green light is passed on to the retina using a contact lens. The light produces a small burn on the unhealthy retina and diverts blood flow to the healthy retina. This can be done in a single sitting and takes about 5 minutes.
Retinal laser is a very simple procedure done in an outpatient setting. Anesthetic drops are instilled in the eye of the patient. A contact lens is applied on the eye and a green light is passed onto the retina through the lens. This is a painless procedure without any side effects. It takes about 5 minutes.
Macular degeneration is a condition in which the macula or the central portion of the retina undergoes degenerative changes. This causes distortion or loss of central vision. The two types of macular degeneration are dry and wet type.
In dry macular degeneration there is a slow and gradual loss of central vision. There is no treatment for this condition and is an age-related process.
In wet macular degeneration, also called choroidal neovascularization or CNV, a vascular membrane grows under the macula causing bleeding and leakage of fluid. This causes sudden loss of central vision or sudden distortion of vision. Patients often describe a black patch in the vision. This requires immediate treatment with anti-VEGF injections.
What is Dry Macular Degeneration?
A macular hole is a punched-out defect or a hole in the macula. The causes loss of central vision. This condition is mostly idiopathic, but can occur due to trauma.
Macular hole is treated only with surgery. Vitrectomy is done to remove the vitreous inside the eye and then a thin film called Internal limiting membrane is peeled off from over the macula. Later gas or oil is injected into the eye and the patient is give face down positioning for a few hours a day, for a week.