Eye allergies, also called allergic conjunctivitis, occur when the protective outer layer of the eye and eyelid, called the conjunctiva, becomes swollen and inflamed because of allergens or irritants.

Whenever you have eye allergies, the mast cells lining the conjunctiva release histamine when being exposed to allergens and irritants. These allergens and irritants cause the eye conjunctiva to swell and symptoms of eye allergies to occur. 

Common symptoms include:

• red, irritated, watery and itchy eyes
• burning sensation in eyelid, swelling blurred vision ,sensitivity to light.
• Hot, dry weather dries out the eyes and makes eye allergy symptoms worse.

Allergens as well as irritants can cause allergic conjunctivitis.

Environmental triggers of allergic conjunctivitis include:

•  Pollens
• Molds
• Dust mites
• Pets

 Irritants that may cause eye allergies include:

• Cigarette to smoke
• Cosmetics
• Perfumes
• Contact lenses
• Contact lens solutions

• Eye puffiness or swelling is a common manifestation of allergic conjunctivitis, along with itchy, red eyes, a burning sensation and a clear, watery eye discharge.  
• At the time of an allergic reaction, white blood cells attach to protective mast cells in the mucus membranes of the eyes and nasal passages, and fluid builds up.
• Eyelid swelling often occurs at night. Important reason this happens is exposure to allergens in the bedroom – primarily dust mites and/or pet dander.  

This is also called the “allergic shiner” – when there is swelling of tissue and fluid buildup in and around the eyes, blood starts to pool around, darkening the skin and creating dark circles. The “allergic shiner” is also a very common sign of environmental allergies to pollen, dust mites or pet dander, and it may also indicate food allergy.  

The best possible thing to do is to totally avoid whatever eye allergens and irritants that troubles your eyes. But, this is hard since these triggers are airborne.  

Here are some suggestions to keep your eyes clear, clean and comfortable: 

• Use a preservative-free eye wash or artificial tears to moisten dry, irritated eyes and help clear out allergens and irritants. 
• Put a damp washcloth in the freezer for some minutes and then apply it to your eyelids to reduce itching and swelling.  
• Keep your hands away from your eyes. Wash your hands and face after coming from outside on high pollen and mold days. 

• First of all, consult with your doctor about developing an allergy treatment plan that addresses nasal, respiratory and eye symptoms.  You can read from here
• Over-the-counter and prescription eyedrops and oral medications can also be used to treat eye allergies.  options available here

If your eyes are feeling dry and irritated in the winter months when there are  very fewer outdoor allergens, then you might have a form of tear dysfunction known as dry eye, or “keratoconjunctivitis sicca.” This isn't an allergic reaction – it happens when your eyes either do not make enough tears or the tears they make go away very quickly.  You can read detail here

Artificial tears or lubricant eye drops – are the mainstay treatment for dry eye. They will keep the eye moist and reduce symptoms. You can buy artificial tears at a drug store without a prescription or online from here. They come in liquid, gel or ointments. Preservative-free artificial tears are best for long-term use, but they are more expensive.  

Different things you can do to improve dry eye include:  

• Try to blink a lot, specially whenever you are reading or using a laptop /computer. This helps to keep your eyes moist. 
• Avoid excess air conditioning or heating as much as possible. Also always try to avoid sitting directly in the flow of cold or hot air.