Symptoms of Dry Eye:
- Feelings of dryness, grittiness and burning sensation that characteristically worsen over the course of the day.
- Stringy discharge, transient blurring of vision, redness and crusting of the lids are also common.
- Sensitivity to light, Difficulty with nighttime driving.
- Foreign Body (FB) sensation
- Watery eyes, which is the body’s response to the irritation of dry eyes.
- Lack of emotional or reflex tearing is unusual.
Signs of Dry Eye:
1. In Eyelid:
- Posterior (seborrhoeic) blepharitis.
- Meibomian gland dysfunction.
2. In Conjunctiva:
- Redness.
- Staining with fluorescein and rose Bengal.
- Keratinization.
- Conjunctivochalasis.
3. Tear film:
- In the normal eye, When the tear film breaks down the mucin layer becomes contaminated with lipid but is washed away.
- In the dry eye, The lipid-contaminated mucin accumulates in the tear film as particles and debris that move with each blink
- The marginal tear meniscus (strip), In the normal eye the meniscus is 0.20.4 mm in height but in dry eye becomes thin or absent.
4. In Cornea:
- Punctate epithelial erosions, that stain well with fluorescein
- Filaments, stain well with rose Bengal but less with fluorescein.
- Mucous plaques, occur in severe dry eye.
Investigation to diagnose Dry Eye:
- The aim of investigation is to quantify and confirm a clinical diagnosis of dry eye.
- The tests measure the following parameters:
1. Stability of the tear film:
- Tear break-up time (BUT).
2. Tear production:
- Schirmer Test.
- Fluorescein clearance.
- Tear osmolarity.
3. Ocular surface disease:
- Corneal stains
- Impression cytology
- There is no clinical test to confirm the diagnosis of evaporative dry eye.
- Diagnosis is based on the presence of associated clinical findings.
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