When we walk into a glaucoma evaluation in our clinic, we typically have the results of pachymetry, IOP, visual fields and an OCT image of the nerve. For the most part, we have made the decision on the diagnosis of glaucoma before walking into the room.
On the other hand, in our ocular surface disease (OSD) evaluations, we walk into the room with a good case history from our technicians but still have a lot of work to do at the slit lamp to decide if the symptoms or signs come from dry eye disease (DED) or a dry-eye masquerader. And, once we diagnose DED, we still have to convince the asymptomatic patient that he or she does indeed have DED, which can be very time consuming.
So how do we save time and make our practices more efficient? Easy. Know the diagnosis before you walk through the door.
Thankfully, we have seen an exciting trend toward diagnostic technologies that offer objective data for both the structural AND the functional evaluation of OSD. This allows us to know more than ever about patients we have not even met. Current dry eye diagnostics are fast and affordable, which makes them efficient, accessible screening options for most practices. They give us the power to capture virtually everyone with OSD — especially those who are asymptomatic before surgery.
FIRST, EDUCATE THE PATIENT
Set the scene
As so many of us have discovered, if we fail to mention the diagnosis of OSD prior to surgery, our patients will think the OSD was a complication of the surgery. For example, we know that it’s essential to treat OSD prior to cataract surgery to optimize the ocular surface for biometry and ensure patient satisfaction. Studies have shown up to 80% of cataract patients have OSD, yet only 22% of these patients were diagnosed in the past.1,2
In our advanced dry eye referral center, we examine the ocular surface of those patients referred in for OSD, but we also scrutinize the ocular surface during our cataract evaluations.
MEET THE DIAGNOSTIC TOOLS
Questionnaires guide the exam
We start our exams gathering patient data with a validated, low-cost dry eye questionnaire. Most recently, the TFOS DEWS II report recommended using the OSDI, the most commonly used questionnaire for dry eye clinical trials, or the DEQ-5 due to its short nature and discriminative ability.3 We have also used the SPEED questionnaire.
The questionnaire, however, is only the starting point. Based on each patient’s score and other factors, our technicians perform some combination of the following tests looking at the tear film stability, the tear film composition and the ocular surface.
Tear film stability
- Noninvasive tear break-up time (NIBUT). NIBUT is a fast, automated way to get accurate measurements without worrying about influencing the results based on the amount of fluorescein we apply. Research shows NIBUT and fluorescein tear break-up time (FBUT) correlate.4 We prefer NIBUT — not only because we know this data before walking into the room but also because it is very easy to show patients what is actually happening to their tear film. Many diagnostic instruments provide NIBUT; for example, the NIBUT on the Antares (Lumenis) shows orange and red colors where the tear film is breaking up, which allows patients to see what we see with FBUT (Figure 1). Other diagnostic instruments with similar functions are the HD Analyzer (Visiometrics), LacryDiag (Quantel Medical) and the Keratograph 5M (Oculus).
- Meibography. We have several excellent meibography options. LipiScan (Johnson & Johnson Vision) is a fast, small, intuitive HD device designed to make meibography part of the screening process, and Meibox (Box Medical Solutions) was developed with similar goals. Other meibographers allow a glimpse into the function of the meibomian glands in addition to the structure. LipiView II (Johnson & Johnson Vision) offers HD meibography like LipiScan, blink-rate analysis and lipid-layer thickness. Other devices that can obtain meibography in addition to NIBUT include the Antares, the HD Analyzer, LacryDiag and the Keratograph 5M. These devices allow us to quickly obtain images and correlate structures and functions of the tear film in one instrument to help us diagnose dry eye.
- Tear volume. Traditionally, the Schirmer and the phenol red thread test have helped us identify patients with low tear volumes. Reflex tearing can influence both Schirmer, which is an invasive, time-consuming (five minutes) test, and the phenol red thread test, which has lacked consistent results.3 A new test, strip meniscometry (SMTube, Quidel), which is less invasive and quicker, involves dipping a strip for only five seconds into the tear meniscus. Initial results are promising.5
Tear meniscus height (TMH) is another way to obtain a tear volume measurement. Although measuring TMH at the slit lamp has shown poor inter-visit repeatability,6 the development of video-meniscometry and OCT meniscometry has shown promise.7 The Antares and Keratograph 5M are used to measure the TMH prior to entering the exam room. This gives us the ability to combine meibography with NIBUT and TMH — which aids in determining if the DED is primarily aqueous deficient dry eye (ADDE) or a hybrid DED (both evaporative dry eye and ADDE).
Tear film composition
- Tear osmolarity testing. This quick test informs us about the saltiness of patients’ tears. Abnormal (>308 mOsm/L) or asymmetrical (>8 mOsm/L difference between eyes) results with the TearLab Osmolarity Test (TearLab) are more indicative of the DED process. I-Med Pharma’s I-Pen is another handheld tear osmolarity device.
- Inflammatory mediator testing. Dry eye is an inflammatory condition, so it makes sense to test for inflammation. Our clinic uses InflammaDry (Quidel), which assays tear MMP-9 levels. It’s important to remember that InflammaDry is non-specific to the source of inflammation.
A dry eye case study
A 72-year-old woman was referred to us for visually significant cataracts. As part of her workup, our staff performed several dry eye diagnostics, including some advanced tests based on her dry eye questionnaire. Her test results showed she needed treatment for DED before surgery:
This patient had significant MGD, evidenced by meibography, osmolarity and the presence of inflammatory mediators. I correlated her meibomian gland atrophy and NIBUT to show her the functional effects of the dysfunctional glands. We treated her DED with drops for the first two weeks with loteprednol etabonate gel 0.5% (Lotemax, Bausch + Lomb) and cyclosporine 0.05% (Restasis, Allergan).
We discussed LipiFlow, but she wanted to wait and see what the drops did first. When she returned and her topography was fairly similar, she decided to pursue LipiFlow (Johnson & Johnson Vision). After the treatment, topography showed significant improvement, and the patient underwent cataract surgery with Tecnis multifocal IOLs (Johnson & Johnson Vision).
- Ocular surface staining. Corneal and conjunctival staining with sodium fluorescein and lissamine green can be indicators of DED. However, it is vital to remember that central corneal staining with fluorescein is a sign of late-stage OSD.3 The addition of lissamine green to our classic fluorescein examination of the ocular surface makes evaluation of conjunctival staining and lid wiper epitheliopathy easier, which helps diagnose DED earlier.
- Corneal topography. An easy way to help diagnose dry eye before refractive or refractive cataract surgery is to evaluate topography prior to surgery. Patients with OSD can present with inferior steepening but do not have any corneal thinning or irregularities with their posterior vault.8 The OSD can mimic keratoconus-like topography, but, as the OSD is treated, the amount of inferior steepening decreases.8
Putting the data to work
Having many of these diagnostic technologies now combined into one instrument provides us critical information about the ocular surface before we go into the exam room. It makes our technicians more efficient, and it most certainly makes our doctors more efficient. When we see new patients, we can walk into the room knowing their questionnaire scores, NIBUT, TMH, meibography, osmolarity and whether inflammation is present, so we typically already know if they have OSD.
This knowledge gives us more time to educate patients about their specific OSD, and our diagnostic technologies help make patient education more efficient by giving us images that clearly show the pathology and functional effects of dry eye. Most patients have never heard of dry eye and may not even feel the symptoms, but we can show them their abnormal meibomian glands and poor tear film quality to communicate these ideas quickly and effectively.
More advances to come
As we learn all the capabilities of our current tools, more diagnostic technologies and enhancements for DED are headed for our clinics. Also, we are hopeful in the future to have multiple inflammatory mediators (interleukins and other inflammatory cytokines) on one test chip, combined with osmolarity that would guide our treatment decisions. Our patients will benefit from these advances, helping us diagnose dry eye disease more efficiently — and thus treat it more effectively. OM
- Trattler WB, Majmudar PA, Donnenfeld ED, et al. The Prospective Health Assessment of Cataract Patients’ Ocular Surface (PHACO) study: the effect of dry eye. Clin Ophthalmol. 2017; 11:1423-1430.
- Gupta P, Drinkwater, O, VanDusen KW, Brissette AR, Starr CE. Prevalence of ocular surface dysfunction in patients presenting for cataract surgery evaluation. J Cataract Refract Surg. 2018;44:1090-1096.
- Wolffsohn JS, Arita R, Chalmers R, et al. TFOS DEWS II diagnostic methodology report. Ocul Surf 2017;15:539-574.
- Mooi JK, Wang MT, Lim J, Muller A, Craig JP. Minimising instilled volume reduces the impact of fluorescein on clinical measurements of tear film stability. Cont Lens Anterior Eye. 2017;40:170-174.
- Ibrahim OM, Dogru M, Ward SK, et al. The efficacy, sensitivity, and specificity of strip meniscometry in conjunction with tear function tests in the assessment of tear meniscus. Invest Ophthalmol Vis Sci. 2011;52:2194-2198.
- Nichols KK, Mitchell GL, Zadnik K. The repeatability of clinical measurements of dry eye. Cornea. 2004;23:272-285.
- Chan HH, Zhao Y, Tun TA, Tong L. Repeatability of tear meniscus evaluation using spectral-domain Cirrus HD-OCT and time-domain Visante OCT. Cont Lens Anterior Eye. 2015;38:368-372.
- De Paiva CS, Harris LD, Pflugfelder SC. Keratoconus-like topographic changes in keratoconjunctivitis sicca. Cornea. 2003;22:22-24.