Back to basics, part 3
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It is autumn on the North Coast. Longer nights lead to deeper insights as we contemplate the winter solstice. As usual, I am thinking dry eye. It is, as they say, how I roll.
If you recall, I promised one of the guests at a dinner presentation that I would spend a column or four on topics that touched on the basics of diagnosing and treating dry eye disease (DED). While this doctor may have been gently poking fun at the DED-obsessed and our interest in the nuanced and the new, they really did seem to have a sincere interest in learning more foundational concepts.
In part 1, I reviewed the three types of human tears and their characteristics when they are normal. Part 2 was snuck into my annual anti-inflammatory review last month; after a long discussion about the state of the state for steroids, immunomodulators and of course my white whale AzaSite (azithromycin ophthalmic solution 1%, Thea), I pointed out that immunomodulators continue to form the backbone of our treatment paradigms. Almost all types of DED have some aspect of inflammation, a foundational concept, and addressing that inflammation in some manner is an equally foundational aspect of DED treatment.
What could be more basic than making the diagnosis of DED? In a recent dry eye blog post, I shared recent statistics on dry eye prevalence and the demographics of people who suffer from DED. For the first time since 2017, we have updated information. As many as 150 million Americans may be experiencing dry eye symptoms, and nearly 38 million have been diagnosed. For the first time in more than a decade, we are seeing the number of people who are being actively treated start to inch up from 1.25 million; at the time I wrote this, we were over the 1.5 million mark and climbing. Why have these numbers climbed? A greater awareness of DED in both the general public as well as the eye care community is certainly a factor, as is the arrival of more effective, better tolerated treatments.
The diagnosis of DED begins with the very first encounter a patient has with your practice. Whether a patient schedules their visit by phone or online, they are being asked why they wish to see you. It is simply astonishing how frequently they tell your staff that they need an appointment because — wait for it — their eyes are dry! Yup, the most frequent complaint made by a dry eye sufferer is dryness. No way to miss that.
If your patient is not quite that accommodating, it will be necessary to ask them some questions. There are several symptom surveys that have been used to diagnose DED and stratify its severity. The simplest among these is the SkyVision Centers one-question survey: Do you take eye drops? We have found that 95% of patients who end up with a relevant diagnosis have DED. No lie. Most of them think they are treating “sinus.” I have no idea what “sinus” is. No one does. It is the low back pain of head and neck medicine. If you discover what it is and find a cure, you will win Nobel Prizes in Medicine, Literature and Peace.
“Sinus.” Sheesh.
Three other surveys are in common use. The Ocular Surface Disease Index (OSDI), developed by Allergan, is particularly good in aqueous-deficient DED and neurogenic pain. The Symptom Assessment in Dry Eye (SANDE) and visual analog scale (VAS) are both linear scales. VAS is particularly simple: Put your finger on a “button” and move it from zero symptoms on the left to however badly you feel on a scale up to 100. We are seeing this in most FDA trials of late. We tend to favor the Standard Patient Evaluation of Eye Dryness (SPEED) test. As many as 85% of DED sufferers have a least a component of evaporative DED, and SPEED is particularly good at following symptom trends in this type of DED. It tends to predict which patients will benefit from in-office therapy, too. We lop off the bottom half to make it quicker and easier.
This is a series on the basics of DED, so we are going to keep things super simple. Got a slit lamp of two? Great! You can be a DED doc. It does not matter who does the slit lamp stuff, but I think it matters that the aspects of the exam that occur at the slit lamp in a basic workup should go in something close to the order I am about to propose. Got a rock star tech working up your patients? Good for you! All you need is data acquired in a consistent manner to make your treatment decisions.
Do not put anything in the eyes before you start your exam. Not kidding. Nothing. You want to get a look and do some testing before you muddy the waters, so to speak. Look at the lids. Are there angry-looking blood vessels covering the lid margin? No touching; not yet. Have the patient look up and observe whether or not the lower lid maintains contact with the eye. Next, ask them to look down and examine the base of the eyelashes for collarettes, those cylinders that cuff the bottom of the lashes when the follicles are teeming with Demodex mites. Yuck. Push on the lid margin with your fingertip and observe the oil that appears at the meibomian gland orifices. Normal is easily expressed clear oil.
Now, take a wisp of tissue, a Q-tip with its cotton drawn out or, for you fancy types, a piece of dental floss and use it to test for corneal sensitivity. Non-mentholated! Are you a barbarian?! Your patient should blink like someone just poked them in the eye. If they just sit there calmly allowing you to plop something on their cornea, well, that would be abnormal.
OK. Now you can put stuff in the eye. Moisten a fluorescein strip, place it in the inferior cul-de-sac and ask your patient to blink a few times. Do they complete the task by fully closing the lid? Does the conjunctiva “wiggle?” Count how long it takes for the first dark spot to appear in the tear film to determine the tear breakup time; the tear film should remain smooth and uninterrupted for 8 to 10 seconds. Is there any fluorescein staining of either the cornea or the conjunctiva? Any staining of either or both surfaces is abnormal.
I know this is a “basics” primer, but almost anyone can do two more very simple tests at this point. If you want to be super complete in your search for inflammation, or if you want to show off at a dinner talk, you can now put a bit of lissamine green in the eye to more accurately diagnose conjunctival involvement. Otherwise lovely people become downright indignant over the question of whether you wait 2 or 5 minutes to take a look. We are in your office; you make the call. To be honest, we should probably all be doing a Schirmer test with anesthesia on a first DED visit. This is the time to put a drop of anesthetic in the eye and let those strips percolate for 5 minutes. Anything under 10 mm is abnormal.
There you have it. The most basic of basic dry eye exams. All of this can be achieved with as little as 5 minutes of your direct time. Next month, we will review what kinds of diagnoses the typical combinations of findings add up to. Because this is Ocular Surgery News, I reserve to right to add in topography and biometry as basic tests. Eventually, we will get around to talking about DED treatment 101.
Unless Brent Saunders buys or sells something. Or Bob Dempsey comes out of witness protection.
- References:
- Millions of Americans experience dry eye symptoms, yet new national survey shows sufferers struggle to find relief. https://ir.bausch.com/press-releases/millions-americans-experience-dry-eye-symptoms-yet-new-national-survey-shows. Published July 8, 2024. Accessed Sept. 3, 2024.
- Multi-sponsor Surveys’ 2022 study of dry eye sufferers. https://www.multisponsor.com/wp-content/uploads/2023/01/Dry-Eye-Sufferers-MS2215.pdf. Published August 2022. Accessed Sept. 3, 2024.
- For more information:
- Darrell E. White, MD, of SkyVision Centers in Westlake, Ohio, can be reached at dwhite@healio.com.
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