A macular scar is a scar at the central part of retina at the back of the eye. Fovea is a smaller area at macula where sharpest image is formed. Macula is responsible for central vision and any disease of macula results into poor central vision.
There are many diseases and pathological processes which affect the macula by first causing inflammation, bleeding and/or exudation and then proliferative or atrophic scarring of macula. These pathologies may be present at the time of birth or may appear later during childhood or even develop later in middle age or old age.
Some causes of macular scar are genetic disorders while some are infective or degenerative in nature. Depending on the cause, the disease and the consequent macular scars may be found in one or both eyes.
Some of the causes of macular scar in children and young adults are macular dystrophies (premature death of macular tissue), retinal telangiectasia (abnormal vessels at macula) and some ocular infections such as Toxoplasmosis and Ocular Histoplasmosis Syndrome (OHS).
While there are other less common disease processes which could potentially affect the macula and therefore cause scarring in young adults and middle age individuals, the most common cause of macular scar in older age group is neovascular type of Age-related Macular Degeneration also known as wet AMD.
Anomalies in central vision is tested with Amsler grid chart. This test can be done even at home.
In cases where the pathological process is associated with pain and redness of the eye, consequent visual loss is almost always noticed by the patient. In cases where the disease process is ‘silent’, loss of vision because of macular scarring may not be noticed by the patient when it is only in one eye and the other eye has normal vision.
There are many such patients with unilateral macular scar who cannot detect poor vision in the affected eye for many months or even years. They only notice it when they, for some reason, cover their good eye and notice that the uncovered eye has poor vision.
There are two important points for such patients here. First, they should consult an ophthalmologist for a detailed eye examination to ensure that the disease process in not progressive and that it is not bilateral. In either case, appropriate treatment will be prescribed depending on the cause.
The second point is that macular scarring usually causes irreversible loss of vision in the eye. If it is present in only one eye, the other eye has to be properly taken care of. Since the patient is left with only one functional eye, it is important to immediately consult an ophthalmologist as soon as any symptoms (especially visual) appear.[Image by National Eye Institute/ CC BY 2.0]