Your Dry Eye Evaluation

Why the cause matters

Artificial tears treat a symptom. If the tear film is unstable because the meibomian glands are blocked and the oil layer is missing, drops give a few minutes of relief and the surface dries out again, which is the experience most patients have had before they arrive. Treating the glands treats the cause. If instead tear production is low, or the surface is inflamed, or the lids are the problem, the treatment is different again. The evaluation exists to sort these out.

Before your visit

Bring a list of every drop you use and how often, your medications, and a note of when symptoms are worst. Leave contact lenses out on the day. Do not use drops for two hours before the visit so the tear film can be measured as it is. A short questionnaire scores your symptoms so that improvement can be measured later.

The tests

The tests are selected for your symptoms and may include:

• Tear film analysis: how quickly the tear film breaks up between blinks, imaged without dye, and the thickness of the oil layer measured by interferometry
• Meibography: infrared imaging of the meibomian glands through the eyelid, showing which glands are blocked, shortened or lost
• Tear osmolarity: the salt concentration of the tears, which rises in dry eye and indicates severity
• Inflammation testing: a rapid test for MMP-9, an inflammatory marker, which decides whether anti-inflammatory treatment is needed
• Tear volume: a Schirmer strip or meniscus measurement showing whether production is low
• Slit lamp examination of the lids, lashes, gland openings and the ocular surface with dyes that show dry or damaged areas
• Expression of the glands to see whether oil flows normally, is thick, or is absent

The diagnosis and the plan

The findings place your dry eye in one or more categories: evaporative from meibomian gland dysfunction, aqueous deficient from low production, inflammatory, lid related from blepharitis or rosacea, or mixed. They also grade how severe it is and how much gland structure remains, which shapes what is achievable. You leave with a clear plan: which treatments, in what order, and when to return to measure the effect. Most patients need a combination, started stepwise, rather than one fix.

Dry eye and surgery

A stable tear film is a requirement for accurate measurements before LASIK, cataract and lens surgery, and for a comfortable, clear result afterward. Patients found to have dry eye at a surgical consultation are treated first and re-measured; the surgery is scheduled once the surface is stable. This adds a few weeks and materially improves outcomes.