Retina is the innermost light sensitive layer of the eye. It converts the light rays (from any objects in front of eyes) into sensory impulses which travel through the optic nerve to the visual centre of our brain. There only the impulses are interpreted as images of what we see (objects). If you compare the eye with a camera, then the retina represents the film (negative).
Symptoms of various vitreo-retinal disorders:
# Gradual or sudden loss of vision
# Blurring of vision with spots or floaters
# Seeing distorted images or wavy lines
# Shadow in the field of vision
# Flashes of light
Various retinal diseases:
1. Retinal Detachment (RD): In this condition, retina partly or completely lifted up from it’s posterior attachment.
3. Age Related Macular Degeneration (ARMD): ARMD or age related macular degeneration is a disease of the retina which usually affects persons above 65 yrs of age. Oxidative stress also plays an important role in the development of ARMD. In ARMD, the normal photosensitive cells of the retina undergo degenerative changes. The symptoms are mostly blurring of central vision and distorted images.
ARMD can be of two types, Dry and Wet.
Dry AMD is the common and less dangerous variant. However, treatment for dry AMD is only nutritional supplementation.
Wet AMD is the rarer but more vision threatening condition. It is treated with intravitreal injections of various anti VEGF.
4. Retinal vessels occlusion: Retina is a very vascular structure and it’s cells can withstand only 90 minutes of cutoff blood supply or oxygen supply. Beyond that time, irreversible damages happen to the cells of the retina. Retina is supplied by Central Retinal Artery and drained by Central Retinal Vein. Either the artery or the vein or any branches of those can get occluded. These happen more commonly in hypertensive and cardiac disease patients.
Retinal Artery Occlusion – It can be CRAO or Central Retinal Artery Occlusion OR BRAO or Branch Retinal Artery Occlusion. CRAO is an actual eye emergency, as the patient loses vision completely and if retinal circulation could not be re-established within an hour, vision loss would be permanent.
Retinal vein occlusion: It can be CRVO or Central Retinal Vein Occlusion OR BRVO or Branch Retinal Vein Occlusion. These are kind of strokes in the eye. Symptoms would be blurring of vision (when there is macular edema), or completely symptomless (when only peripheral vessels occluded and central retina or macula remains unaffected).
Treatment of Macular Edema is various Anti VEGF (Vascular Endothelial Growth Factor) and long acting corticosteroid implants injection intravitreally. Systemic control of blood pressure and cardiac diseases are very important.
5. Central Serous Chorio-Retinopathy (CSCR): In this condition fluid gets accumulated under the photosensitive layer of the central retina (macula). It can be idiopathic but more commonly happens in young adults (males) with type A personality. It is commonly associated with increased levels of corticosteroids in the body either endogenous or supplied through medicines.
Symptoms are usually blurring of the central image or black spot at the centre of the visual field and wavy or distorted lines.
Treatment is often observation only if the CSR is small, recent and acute onset and symptoms are less. Often lifestyle modification, decreasing level of stress and withdrawal of offending medicines help to dissolve the accumulated fluid under retinal layers. If the condition does not resolve even by 3 months time, usually focal laser treatment of the retina is needed.
6. Macular Hole: In this condition, there is a small round break at the macula which is the most light sensitive central area of the retina. Macula gives us sharpest vision for reading, writing, driving and seeing all finer details. Hence, a macular hole causes blurred and distorted central vision.
Treatment is surgical closure of the macular hole.
7. Retinopathy Of Prematurity (ROP):
ROP is a potentially blinding disease of the retina, that affects premature infants usually of birth weight less than 1500 gms or born before 31st weeks of pregnancy. The earlier the baby is born and less the body weight at birth, the chance of developing ROP is more. Another risk factor for developing ROP is oxygen therapy at incubators for the premature babies. ROP affects both the eyes of a baby, however the grade of involvement can be different in two eyes. If not treated properly, ROP causes permanent loss of vision. Hence it is very important to show each premature baby to a retina specialist who is trained to treat ROP.
ROP has various stages. Higher the stage, more chances of permanent visual impairment. Treatment involves retinal cryotherapy, lasers & Anti VEGF injections inside the eye.
Concerned Doctor at Nayonika Eye Care: