Can you tell me something about eye allergy and swelling in the iris?

This eye allergy comes only in monsoons. It is very painful and we cannot face sunlight or any light.

In anatomy, the iris (plural irises or irides) is the most visible part of the eye of vertebrates, including humans. The following covers the iris of vertebrates, not the separately evolving iris found in some cephalopods. The word comes from Greek mythology, in which Iris is the personification of the rainbow.

The iris consists of pigmented fibrovascular tissue known as a stroma. The stroma connects a sphincter muscle (sphincter pupillae), which contracts the pupil, and a set of dialator muscles (dilator pupillae) which open it. The back surface is covered by a two-cell-thick epithelial layer, the iris pigment epithelium, but the front surface has no epithelium. The outer edge of the iris, known as the root, is attached to the sclera and the anterior ciliary body. The iris and ciliary body together are known as the anterior uvea. Just in front of the root of the iris is the region through which the aqueous humour constantly drains out of the eye, with the result that diseases of the iris often have important effects on intraocular pressure, and indirectly on vision.

When photographed with a flash, the iris only reacts to protect the retina, and not fast enough to avoid the red-eye effect. This represents reflection of light from the back of the eye, and is closely related to the term red reflex, used by ophthalmologists in describing appearances on fundal examination.

When used as a descriptive term in medicine, the meaning of "red eye" is quite different, and indicates that the bulbar conjunctiva is reddened due to dilatation of superficial blood vessels. Leaving aside rarities, it indicates surface infection (conjunctivitis), intraocular inflammation (e.g., iridocyclitis) or high intraocular pressure (acute glaucoma or occasionally severe, untreated chronic glaucoma). This use of "red eye" implies disease. The term is therefore not used in medicine for ocular albinism, in which the eye is otherwise healthy despite an obviously red pupil and a translucent pinkish iris due to reflected light from the fundus. "Red eye" is used more loosely in veterinary practice, where investigation of eye diseases can be difficult, but even so albinotic breeds are easily recognised and are usually described as having "pink eye" rather than "red eye".

Are you sure it is an allergy?
In the allergy,two eyes are affected.There is conjuctivitis (red eyes) and tears,often with nose secretion.
Maybe mechanical iritation is with you.
GO GET CHECKED OUT HUN!