Dry eye

Dry eye is the most common cause of eye discomfort leading to irritation in the eye, eye redness, watering of the eyes, itching of the eyes and tiredness. The incidence of dry eye is increasing day by day and it has been noted that 1 out of 3 persons in the age group of 21-40 years have dry eye. The most common cause is increased screen exposure of more than 4 hours per day. Increased age, Diabetes, hypertension, autoimmune diseases like Rheumatoid arthritis, and thyroid disorders contribute to dry eye.

To understand dry eye better, we should look at the natural tears produced by the eye. Tears have to coat the eyeball so that the eyelids blink smoothly, corneal health is maintained and one keeps on seeing clearly. Any factor that interferes with the tears, eyelids, or ocular surface (cornea) will lead to ocular discomfort and dry eye.

Natural tears are necessary and create a tear film over the eye which is composed of three layers. The outermost layer called the lipid layer which is an oily layer produced by Meibomian glands in the upper and lower eyelids. The aqueous or watery layers form the bulk of the tear film and are produced by lacrimal glands. The innermost thin layer is the mucin layer produced by the goblet cells of the conjunctiva, which is the white part of the eye.


Any imbalance in tear film leads to dry eye. Defect in the oily outermost layer is the most common cause of dry eye. Meibomian gland disease (MGD) is the most common cause of that defect leading to evaporative dry eye. When the aqueous or watery layer is affected the term secretory dry eye is used.

The most common causes of dry eye are

  1. Age: As one age the active secretion from glands of eyelids or lacrimal glands decrease.

  2. Systemic Diseases: Diabetes, Hypertension, thyroid disorders, Autoimmune disorders, hormonal changes

  3. Digital screen exposure: people with more than 4 hours of digital screen exposure have increased chances of developing dry eye

  4. Poor diet and exercise

  5. Contact lens users

  6. Post-surgery: dry eye incidence increases after any eye surgery like cataract surgery or refractive (spectacle removal) surgery, but usually subsides 1-3 months after surgery.

  7. Oral medications: Antihistaminic, Anti-depressants, and hormonal pills can increase dry eye.


Treatment of dry eye begins by finding out the cause of dry eye and trying to eliminate that factor. The next step is to assess severity, which is commonly done by dry eye workup.

Dry eye workup conventionally involves the use of filter paper strips to assess, tear secretion, and tear evaporation. Modern-day equipment or Ocular surface analyzers (Lipiview by johnson, OSA or IDRA) are able to assess tear secretion, tear evaporation, Meibomian gland imaging, osmolarity, lipid layer thickness, conjunctival health with minimal discomfort to the patient.

The most common type of dry eye that is detected after these tests is Evaporative dry eye  (EDE) where the defect is primarily in lipid layer production leading to increased evaporation of tears. Treatment of Evaporative dry eye involves the use of heating pads, eyelid massage, ointments and eye drops. In advanced cases, one may need treatments like Lipiflow, Intense pulsed Light Treatment (IPL) or both.

Aqueous deficient dry eye (ADDE), is the next common type of dry eye where the lacrimal gland is not producing enough tears. Eye drops, Anti-inflammatories, Steroids, Punctal Plugs, and Surgery are various modes of treatment that are used to treat this kind of dry eye.

The third kind which is Mixed dry eye and as the name suggests is a mix of both EDE and ADDE is on a rise and requires a combination of treatments.

This small brief of dry eye is to make you understand the basics and is not treatment aadvice Your doctor at Comet Eye Hospitals will be able to assess you and suggest the best dry eye treatment customized to your needs.

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