• Tears are a complex mixture of water, fatty

oils, and mucus.

• This mixture helps make the surface of

your eyes smooth and clear, and it helps

protect your eyes from infection.

Sometimes, a person with a dry eye will have excess tears

running down the cheeks, which may seem confusing.

This happens when the eye isn't getting enough lubrication.

The eye sends a distress signal through the nervous

system for more lubrication. In response, the eye is flooded

with tears to try to compensate for the underlying dryness.

However, these tears are mostly water and do not have the

lubricating qualities or the rich composition of normal tears.

They will wash debris away, but they will not coat the eye

surface properly.

1- Poor tear quality

The tear film has three basic layers: oil, water and mucus.

Problems or imbalance with any of these layers can cause dry

eyes symptoms.

2- Decreased tear production as in

•People older than 50 .

•Postmenopausal woman .

•Have a medical condition that reduces your tear production

such as diabetes, rheumatoid arthritis, lupus, scleroderma,

thyroid disorders and vitamin A deficiency.

•Have had laser eye surgery ( LASIK ).

•Have tear gland damage as from inflammation or radiation

3- Eyelid problems

Blinking spreads a continuous thin film of tears across the

surface of your eyes.

If you have an eyelid problem that makes it difficult to

blink, tears may not be spread across your eye

adequately or your tears may evaporate too quickly,

causing dry eyes.

Eyelid problems can include an out-turning of the lids or

an in-turning of the lids .

4- Medications that cause dry eyes

•Some drugs used to treat high blood pressure (BETA

blockers )

•Antihistamines and decongestants

•Hormone replacement therapy

•Certain antidepressants

•Isotretinoin-type drugs for treatment of acne

5- Additional causes

•Wind

•Dry air

•Tasks that require enough concentration that you blink

less often, such as working at a computer, driving or

reading

When tears do not adequately lubricate the eye, a

person may experience:

• Pain

• Light sensitivity

• gritty sensation

• feeling of a foreign body or sand in the eye

• Itching

•Eye fatigue

• Redness

• Blurring of vision

• Artificial tear drops and ointments

• Temporary punctal occlusion

• Non-dissolving punctal plugs and punctal

• occlusion by cautery (application of heat to tear

exit duct).

• There is growing evidence that increasing the

oral intake of fish oil and omega-3 via diet or

supplement is very helpful to those suffering with

dry eye.

THANK YOU