What are the common signs and symptoms of dry eye?

Sandy or gritty feeling
Dryness
Redness
Watery eyes
Constant or occasional tearing
Burning
Itching
Contact lens discomfort
Dryness when staring at a computer screen
Sensitivity to light
Eye pain or discomfort
Stickiness
Tired eyes
Fluctuating or decreased vision

Why is it that for the most part, I do not feel anything?

As in many disease entities, tissue degradation and adaptation is very common over time. Most people who have had LASIK do not feel any symptoms because the nerve endings that provide the "feel" sensation to the eye are burned during the procedure. In other cases and common in systemic disorder such as Sjogrens or Arthritis, the tissue changes are chronic and there is a slow adaptation. During the exam we often hear more complaints about signs, most commonly eye redness and tearing. The redness comes from the chronic inflammation and the response of the blood vessels is to dilate or become bigger in diameter thus giving the impression of redness. The typical sign is often a spontaneous tearing that occurs, similar to when you are exposed to any eye irritant and the eyes water and tear.

What is the composition of the tear film?

Mucin layer – This is the most posterior layer of the tear film lying adjacent to the corneal and conjunctival surface. This layer serves as a wetting agent allowing the aqueous (tears) to spread evenly over the front of the eye.
Aqueous layer – This is the largest portion of the tear film lying between the mucin and lipid layers. It serves as the fluid hydrating portion of the tears.
Lipid layer – This is the most anterior (external) layer of the tear film. It prevents evaporation of the aqueous layer.


What is the function of the tear film?

Tears provides the anterior corneal and conjunctival surface of the eye with lubrication, hydration, oxygen, protection, and nutrients. Creates a smooth optical surface for the cornea. Tears also help remove foreign bodies (particles) or microorganisms from the anterior surface of the eye.

Decreased aqueous production– This may be caused by lacrimal gland dysfunction, systemic disease, medications, or trauma.

Evaporation of tears – Evaporation causes decreased tear volume.

Eyelid anomalies - Often after eye surgery

Ectropion – The lower lid turns away from the eye which may increase evaporation of the tears.

Entropion – The lid and lashes turn toward the eye which may affect the tear film.

Exopthalmos – The eye bulges forward abnormally causing the eyelids to spread apart.

Lagopthalmos – With this condition it is difficult to completely close the eyelids.

Lipid deficiency – Decreased lipid layer causes increased evaporation of the aqueous layer

Blepharitis – This eyelid inflammation often has dandruff-like skin cells t rapped on the eyelashes.

Meibomianitis – This is meibomian gland inflammation.

Inspissated meibomian glands – Meibomian gland secretion hardens leaving a cap over the gland orifice.

Mucin deficiency – Loss of this layer decreases tear film stability leading to evaporation of the aqueous layer.

Reduced blink reflex – Loss of corneal sensitivity leads to decreased blink reflex and less reflex tearing.  Causes of decreased corneal sensitivity

Post refractive surgery – Creation of the corneal flap may decrease the function of the nerves in that area reducing corneal sensation and the blink reflex. This tear film status should return to normal approximately six to nine months after the surgery.

Contact lens wear - This may decrease corneal sensitivity. Excessive wear of contact lenses may compromise the corneal surface and lead to abnormal wetting of the surface.

Systemic disorders – These may affect corneal sensitivity.

Uneven distribution of tears – Can lead to exposure of the cornea and conjunctiva.

Are there other factors which may affect dry eye?

Symptoms may be more apparent with:

Do you recommend over the counter tears? NO!!!!

One common problem of over the counter drops is that in low tear volume patients, these compounds dilute the normal proteins that provide protection to the eyes. We DO NOT recommend tears for most of our patients for this reason. 

Are all eye drops the same? NO!!!!

Low viscosity artificial tears – These drops are added to increase the watery portion of the tear film. Preservatives are added to multi-dose (larger) bottles to maintain sterility. Sterile, non-preserved, single-dose containers are also available. Multi-dose bottles can also be made with preservatives that dissipate when in the eye yet still maintain sterility in the bottle.

High viscosity artificial tears - These solutions have an increased concentration of viscosity agents.

High viscosity ointment – These ointments provide a coating over the eye that will not evaporate or drain from the eye as quickly as artificial tears.

Contact lens drops – These solutions are formulated to apply to the eye while wearing soft or hard contacts.


What do you recommend to treat dry eye?

There are various treatment options and ech is dependent on the type of tear dis-function you have:

Cyclosporin A – This immunomodulator is used in patients whose tear production is reduced due to ocular inflammation.
Topical steroid – This is used to treat inflammation.

Doxycycline – This is used when dry eye is caused by blepharitis.

Azythromicin - This antibiotic, on topical use,  has been proven useful in the treatment of Ocular Surface disease

Collagen Inserts- A slow disolvable collagen plug that desintegrates during the day.

Collagen punctal plug – The drainage areas are plugged to retain tears. This temporary plug will dissolve within days.

Silicone punctal plug – This plug does not dissolve and is used as a long term solution to treat severe dry eyes. The plug may be removed if needed.

Mist spray – This spray increases the aqueous layer of the eye.

Humidifier – This device increases the moisture in the environment.

Moisture chamber goggles – Humidity is maintained within the protective glasses due to decreased evaporation.
Nutrition and supplementation – Proper balance of fatty acids may affect the dryness of the eye.

Edited by Dr Gonzalez, adapted from :Prevalence of and Risk Factors for Dry Eye Syndrome Scot E. Moss, MA; Ronald Klein, MD; Barbara E. K. Klein, MD Arch Ophthalmol. 2000;118:1264-1268.