When you think of allergies, you think of sinuses, nose or lungs reacting to airborne allergens and pollutants. Your eyes are just as vulnerable. Apart from pet dander and medicine, dust, pollutants, cigarette smoke, perfume and diesel fumes cause irritation and redness when they come in direct contact with the surface of the eye.
Winter smog makes it almost impossible to protect your eyes from allergens, more so after Diwali, when cracker residue, vehicular exhaust and dust combine to form a deadly aerosol that hangs in the air for days.
Tears cannot always wash out these allergens, causing allergic conjunctivitis (swelling of the membrane under the eyelids). Another fallout is the “dry eye syndrome”, which causes chronic lack of moisture in the eyes, causing grittiness and redness in the eye.
Apart from air allergens, medicines, certain foods such as shellfish or shrimp, insect bites and ultraviolet exposure can also cause swollen eyelids, a condition called allergic lid edema.
Contact-lens users also risk giant papillary conjunctivitis, which is an allergic reaction to the contact lens, the protein deposits on the lens or the preservative in the contact lens solution.
Conjunctivitis caused by allergies and infections have similar symptoms, such as redness, itching and swelling. Allergies, however, usually affects both eyes, while redness caused by a virus and bacteria can affect even one. Since the treatment varies depending on the cause, it’s important to diagnose the cause of the redness.
Using cold compresses — a piece of soft cloth soaked in cold water — reduces some of the discomfort in both cases.
If the redness persists, lubricating eye drops to physically wash away allergens and moisten the eye to reduce the dryness and redness. Medicated eye drops such as aspirin and ibuprofen-based medications can help reduce swelling and pain.
Dr Sachdev is the chairman and medical director of the Centre for Sight Group of Eye Hospitals