Allergic conjunctivitis is caused by allergens (substances that cause allergies).

The possible allergens that lead to allergic conjunctivitis are :
- Smoke
- Dust
- Pollens
- Animal hair and feathers.

Redness in the white of the eye and inner side of the eyelid
- Irritation
- Increased amount of tears
- Itching of the eyes
- Ropy discharge from the eyes.

- Avoid exposure to dust
- Contact lenses which are worn must be removed
- For protection, plain glass can be worn
- Hands and eyes must be often washed.
- Use icepacks on eyelids to reduce itching.
- Touching or rubbing the affected eyes must be avoided.
- Steroid eye drops may be used after consulting and under the strict supervision of a registered eye doctor.
- Self-medication with steroids may cause an elevation in the pressure of the eye which may result in glaucoma and eventually irreparable vision loss.

In most of the cases, this disease does not cause vision impairment. This is a chronic disease. So, self-medication should be avoided. Powerful medicines, though sometimes give immediate relief, should not be used with out the advice of a doctor, since they will cause vision threatening side effects.