Dry Eye Evaluation

Why Our Eye Doctor Measures Your Tears and Eye Surface

Why Our Eye Doctor Measures Your Tears and Eye Surface

Many people come to us complaining of burning, stinging, redness, or a scratchy feeling that gets worse as the day goes on. Others notice their eyes water too much, which seems odd but often signals that your tears are not doing their job properly. You might also experience blurry vision that clears when you blink, heavy or tired eyelids, or difficulty wearing contact lenses as comfortably as you used to.

If you find yourself rubbing your eyes frequently or notice symptoms flare up in certain environments like air-conditioned rooms or during screen time, a dry eye evaluation can reveal what is really happening.

When dry eye disease goes untreated, the constant irritation and inflammation can harm the delicate surface of your cornea and conjunctiva. Over time, small scratches and erosions may form. This makes your eyes even more sensitive and prone to infection. Chronic inflammation can also damage the glands responsible for producing tears, creating a cycle that worsens your symptoms.

Early testing helps us catch these changes before they lead to permanent tissue damage or vision problems.

Your symptoms alone do not tell us whether you are making too few tears, if your tears evaporate too quickly, or if inflammation is the main problem. Two patients with identical complaints might need completely different treatments based on what their test results show. By measuring specific aspects of your tear system, we can design a targeted plan instead of trying treatments one by one and hoping something works.

Test data also lets us track whether your treatment is helping or if we need to adjust our approach over time.

Aqueous-deficient dry eye means your lacrimal glands are not producing enough watery tears. Evaporative dry eye happens when your meibomian glands do not secrete enough oil, so tears disappear too fast. Some patients have a mix of both. Others have inflammation or eyelid problems driving their symptoms.

Each type creates a distinct pattern on our tests, allowing us to identify the root cause and choose therapies that address it directly.

Preparing for Your Dry Eye Evaluation

Preparing for Your Dry Eye Evaluation

We begin by asking detailed questions about your symptoms, when they occur, and what makes them better or worse. We also use a validated symptom questionnaire, such as OSDI or SPEED, to quantify how dry eye affects you. Then we perform a series of non-invasive tests that measure tear quantity, quality, and stability, as well as the condition of your eye surface and glands. The entire process is gentle and typically causes little to no discomfort.

You may experience slight irritation from certain dyes we use to highlight areas of damage, but any stinging fades within moments.

On the day of your evaluation, avoid wearing eye makeup because it can interfere with some tests and imaging. Try to arrive well-rested, as fatigue can affect your tear production. If possible, schedule your visit during a time when your symptoms are most typical so we get an accurate picture of your usual eye health.

  • Skip eye makeup on the day of your appointment
  • Get a good night's sleep the night before
  • Choose a time that reflects your normal symptom pattern
  • Avoid using artificial tears, redness relievers, or ointments for at least two hours before your visit unless you need them for comfort
  • Bring your contact lens case and solution in case we ask you to remove lenses
  • Write down any questions you want to ask during the visit

We need to know about all the medications you take, including prescription drugs, over-the-counter pills, vitamins, and supplements. Certain antihistamines, antidepressants, blood pressure medications, and hormone therapies can reduce tear production. Be sure to mention any eye drops you use, even if they are just artificial tears, because some contain preservatives that can worsen dry eye over time.

Please tell us if you use glaucoma drops, isotretinoin, or CPAP, and whether you have conditions like rheumatoid arthritis, thyroid disease, or Sjogren's syndrome. Bring a list or the actual bottles if you are unsure of the names or doses.

Contact lenses can alter your tear film and temporarily change the appearance of your eye surface. If you wear contacts, we may recommend leaving them out for at least 24 hours before your evaluation so we can see your eyes in their natural state. This gives us the most accurate baseline measurements and helps us determine whether your lenses are contributing to your symptoms.

Bring your glasses to wear on the day of the appointment if you need vision correction.

How We Measure Your Tear Production

For this test, we place a small strip of special filter paper inside your lower eyelid while you sit quietly with your eyes closed for five minutes. The paper absorbs your tears, and we measure how many millimeters of the strip become wet. This tells us whether your lacrimal glands are producing a normal volume of tears or if you have an aqueous deficiency. We document whether the test is done with or without a numbing drop, since results differ.

Some patients find the paper slightly ticklish, but the test is not painful and provides valuable information about your baseline tear production.

This test works similarly to the Schirmer test but uses a thin cotton thread coated with a pH-sensitive dye. This test is done with eyes open while you fixate on a target. We place the thread in your lower eyelid for only 15 seconds, during which time your tears wet the thread and cause it to change color. We then measure the length of the color change to assess tear volume.

Because it takes less time, this test is often more comfortable for patients who have trouble sitting still or who blink frequently.

We use a special microscope called a slit lamp to examine the narrow strip of tears that pools along the edge of your lower eyelid. A healthy tear meniscus should be a certain height, and if it looks too shallow, it suggests you are not making enough tears. Typical tear meniscus height is about 0.2 to 0.4 millimeters; values below about 0.2 millimeters suggest low tear volume. Conversely, a very deep tear meniscus combined with symptoms might indicate reflex tearing caused by irritation.

This quick observation takes only seconds and adds context to our other measurements. In some cases, anterior segment OCT can quantify the meniscus more precisely.

Tear osmolarity measures the concentration of salts and other substances in your tears. When your tears evaporate too quickly or you do not produce enough, the remaining tear film becomes more concentrated, or hyperosmolar. High osmolarity is a key marker of dry eye and correlates with inflammation and surface damage.

  • We collect a tiny sample of tears from the corner of your eye
  • We avoid eye drops for at least two hours before this test when possible
  • An automated device analyzes the sample in seconds
  • Values at or above about 308 mOsm per liter, or an inter-eye difference of 8 mOsm per liter or more, support a diagnosis of dry eye
  • This test helps us monitor treatment effectiveness over time
  • We interpret results alongside your other tests, since severity correlation is imperfect

Assessing the Health of Your Eye Surface and Tear Film

After placing a tiny amount of fluorescein dye in your eye, we ask you to blink a few times and then hold your eyes open while we observe under a blue light. We measure how many seconds pass before the first dry spot appears on your cornea. Normal tear breakup time is usually ten seconds or longer, and shorter times suggest your tears are unstable or evaporating too fast.

This test helps us determine if evaporative dry eye is part of your problem. We may also perform a noninvasive tear breakup time using an imaging device so we can assess stability without dye.

These special dyes highlight areas where cells on your cornea and conjunctiva are damaged or missing. Fluorescein glows bright green under blue light and shows corneal damage, while lissamine green stains devitalized cells and mucin-deficient areas on the conjunctiva and does not require a special light. We grade the pattern and extent of staining to assess how much harm dry eye has caused to your eye surface.

The dyes usually rinse away with your tears. They can temporarily discolor tears, skin, soft contact lenses, or clothing, so we protect your clothing and ask you not to reinsert contact lenses for several hours after dye tests.

We may use a quick swab to check for elevated inflammatory markers on the ocular surface, which helps confirm whether inflammation is driving your symptoms.

  • Takes seconds and provides results during your visit
  • A positive result supports adding anti-inflammatory therapy
  • Useful for monitoring response to treatment

Your meibomian glands line the edges of your eyelids and produce the oil that keeps your tears from evaporating. We gently press on your eyelids to see if clear oil flows out easily or if the secretions are thick, cloudy, or absent. We also assess how many glands appear blocked or have stopped working. A healthy oil layer is essential for long-lasting tears.

If we find significant gland dysfunction, we may recommend therapies that target oil production and flow.

We look closely at your eyelid margins for signs of inflammation, crusting, or abnormal blood vessels. Conditions like blepharitis or rosacea can affect your tear quality and contribute to dry eye symptoms. We also watch how completely and frequently you blink, since incomplete blinks prevent your tears from spreading evenly across your eye surface.

  • Check for redness, swelling, or debris along the lash line
  • Identify misdirected lashes that scratch the cornea
  • Observe blink rate and completeness during normal activities
  • Note any eyelid malposition that exposes more of the eye
  • Look for collarettes that suggest Demodex mites
  • Screen for floppy eyelid syndrome and incomplete lid closure during sleep

Infrared meibography lets us visualize the meibomian glands inside your eyelids to assess their structure, length, and any areas of gland dropout. Interferometry can measure the thickness and spread of the tear film's lipid layer during blinking.

We use serial images to monitor stability or progression over time. Photos of the lid margins can document telangiectasia and other signs at the eyelid edge.

What Your Results Tell Us About Your Dry Eye

What Your Results Tell Us About Your Dry Eye

Schirmer test results below five millimeters after five minutes usually indicate severe aqueous deficiency, while values between five and ten millimeters suggest mild to moderate deficiency. Phenol red thread measurements below ten millimeters in 15 seconds also point to low tear volume. These cutoffs assume testing without anesthetic. With anesthetic, baseline values are lower and thresholds differ. These numbers help us decide whether treatments that stimulate tear production or conserve existing tears will benefit you most.

We also consider your symptoms and other test findings to get the full picture.

We use standardized grading systems to score the amount and location of staining on your eye surface. We grade staining with standardized scales so we can track change over time. Central corneal staining often signals severe dry eye or exposure problems, while staining on the nasal or temporal conjunctiva can indicate specific eyelid or blink issues. Higher grades mean more extensive damage and usually require more aggressive treatment.

Tracking staining over multiple visits shows us whether your eye surface is healing or if we need to adjust your therapy.

We combine all your test results, along with your symptoms and how much they affect your daily life, to classify your dry eye as mild, moderate, or severe. We use a composite of symptoms and signs to stage severity and guide stepwise treatment. Mild cases might respond to simple measures like preservative-free artificial tears and lifestyle changes. Moderate dry eye often needs prescription medications or in-office procedures. Severe dry eye may require a combination of therapies and close monitoring to prevent vision loss.

This classification guides our initial treatment plan and helps set realistic expectations for improvement.

If your tests show low tear production, we may recommend treatments that increase secretion or prevent tear drainage from your eyes. If evaporative dry eye is the main problem, we focus on restoring your oil glands and improving lid hygiene. Patients with high osmolarity or significant inflammation might benefit from anti-inflammatory therapies or therapies that address the root cause of the imbalance.

  • Low tear volume: punctal plugs or punctal cautery, tear stimulation with varenicline nasal spray, oral secretagogues when appropriate
  • Gland dysfunction: daily warm compresses and lid hygiene, in-office thermal pulsation, intense pulsed light, or radiofrequency treatments
  • Inflammation and surface damage: short steroid pulses when indicated, prescription anti-inflammatories such as cyclosporine or lifitegrast
  • Tear conservation and protection: preservative-free artificial tears and gels, moisture chamber glasses, environmental modifications
  • Severe disease: autologous serum tears or scleral lenses for surface protection
  • Supplements: discuss options with us, since evidence for omega-3 is mixed

Dry eye is often a chronic condition, so we use follow-up testing to see how well your treatment is working. If your symptoms improve but tests still show significant surface damage, we may intensify therapy. If both symptoms and test results are better, we might simplify your regimen. Repeat testing also alerts us to new problems, such as gland dropout or worsening osmolarity, that require a change in strategy.

We typically recheck your eyes every few months until your condition stabilizes, then less often for maintenance. Follow-up intervals vary by severity and treatment changes.

Frequently Asked Questions

Most dry eye tests cause little to no discomfort. You might feel a slight tickle from paper strips or threads, and some dyes can sting briefly when we apply them. Any irritation fades quickly, and we take care to keep you as comfortable as possible throughout the evaluation.

A comprehensive dry eye assessment usually takes 30 to 45 minutes, depending on which tests we perform and how complex your case is. We set aside enough time to gather thorough information without rushing you through the process.

Coverage varies by insurance plan and the medical necessity of each test. Many diagnostic tests are covered when dry eye symptoms affect your vision or quality of life, but some advanced imaging or specialized measurements might not be. Coverage is typically under medical benefits rather than vision plans. Our office can check your benefits ahead of time and explain any out-of-pocket costs before we proceed.

For the most accurate results, avoid using artificial tears, redness relievers, or ointments for at least two hours before your evaluation unless you need them for comfort. If you do use drops, tell us what and when.

Even on days when your symptoms feel milder, underlying abnormalities in tear production, stability, or surface health usually still show up on testing. If we are concerned that your results do not match your typical experience, we may ask you to return on a day when your eyes feel more symptomatic to capture a complete picture.

Yes. Very low tear production, dry mouth, joint pain, or other systemic symptoms can point to conditions like Sjogren's syndrome. If your testing or history suggests this, we will coordinate appropriate lab work or referrals.

Contact our office right away if you experience a sudden spike in pain, redness, light sensitivity, or vision changes. These could signal an infection, severe inflammation, or a corneal problem that needs prompt attention. We can schedule an urgent visit to assess the situation and adjust your treatment if necessary.

Dry eye tests are very safe, with minimal risks. You might notice temporary blurring or mild stinging from the dyes, and your vision may be slightly hazy for a few minutes afterward. Some patients have a mild allergic reaction to certain dyes, but this is rare. We use sterile, single-use dye strips and materials to reduce infection risk. We monitor you throughout the exam and address any concerns immediately.

Getting Help for Dry Eye Evaluation

If you are struggling with dry, irritated eyes, a thorough evaluation is the first step toward lasting relief. Our eye doctor uses the latest testing methods to identify the specific causes of your discomfort and create a personalized treatment plan that addresses your unique needs. Reach out to schedule your dry eye assessment and start your journey to healthier, more comfortable eyes.