The Dry Eye Zone

Rebecca's Blog

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Study: A snapshot of the scleral lens world today

Contact Lens & Anterior Eye recently published "Visual and physiological outcomes of scleral lens wear" by Muriel Schornack et al.

I enjoyed this study tremendously! It provides a sweeping high-level view of what's going on in the scleral lens world today, across platforms, technologies, practice types and patient types. The authors conducted a survey of scleral lens fitters worldwide, asking them to provide data about the most recent established scleral lens patient they had evaluated, to get a nice random cross-section of scleral lens patients.

In a study like this, you can't lump people together too much, because we are really divided into two very different crowds - the visual indication crowd (dominated presumably by the keratoconus patients) and the dry eye (or "ocular surface disease") crowd. There are other people like me who straddle both - corneal irregularity plus dry eye from LASIK, for example - but most patients have one clear indication for the lenses.

About the doctors surveyed

While the study is focused on the patients, of course, I enjoyed smidgins of data about the medical practitioners:

  • 292 survey responses were analyzed.
  • Only 60% were from the US, which I found pleasantly surprising. 5% Canada, 5% Italy, 4% India, 3% from Switzerland, 3% from South Africa, 2% from Spain, and 1% or less from another 19 countries.
  • Only 12% had more than 10 years' experience fitting scleral lenses. 42% had five or fewer years' experience.

Who are the patients getting scleral lenses?

Here is where it starts getting interesting:

Age. gender and race?

Mean patient age was 45, which is substantially younger than I would have guessed, and the range was 18-86. (I have spoken with several scleral lens patients older than 86, incidentally!)

The gender distribution surprised me too, but only until I looked at the disease breakdown! 63% male, 37% female.

Race-wise, we are 66% white, 16% Hispanic or Latino, 7% Black or African American, and 7% Asian/Pacific Islander

History of eye surgery?

45% of us scleral lens users have had eye surgery. Here are the surgeries that scleral lens users are most likely to have had, starting with the very most likely:

  • Corneal transplant
  • Refractive surgery (e.g. LASIK)
  • Corneal crosslinking
  • Cataract surgery
  • INTACS

(8 other surgery types were reported as well.)

No surprises there, given that most scleral lens users are - as we're about to see - keratoconus patients, 

WHY are we getting sclerals?

The vast majority of us are getting sclerals for vision reasons. Dry eye / ocular surface disease is still a pretty small minority of 13%.

Among the vision indications, corneal irregularity is the vast majority, and within that category, keratoconus rules, at 61% of all scleral lens users.

One thing I found very interesting was the breakdown of patients within the "ocular surface disease" indication:

  • 10 patients (42%) "dry eye syndrome"
  • 4 patients (17%) GvHD
  • 2 patients (8%) exposure keratopathy (e.g. non-closing lids)
  • Every other indication on the list was represented by a single patient, including Sjogrens Syndrome (only 1? Really?), Stevens Johnson Syndrome and neurotrophic keratopathy. These numbers make me quite curious as to whether any PROSE providers participated.

I'd say one of the take-homes of that chart for the dry eye crowd pursuing scleral lenses is that in addition to the broader constraints of scleral lenses being relatively new in most medical practices, very few practitioners have much experience with scleral lenses for dry eye, since they are BOTH new AND treating mostly patients with keratoconus and other vision indications. This is, incidentally, one of the reasons I remain a staunch supporter of PROSE for severe ocular surface disease. They've just been doing it so much longer, and we as patients need that extra experience.

Do we wear lenses in both eyes or just one? And how long have we worn them?

80% of us wear sclerals in both eyes, and the majority of patients being seen are relatively new to scleral lenses, with a mean duration of 2 years.

And what did we do before sclerals?

This, as you might imagine, totally depended on why we are wearing sclerals. 

Of those who got sclerals for vision reasons, nearly half were wearing either regular gas perms, or in some cases hybrids or piggybacks. while about a fifth wore glasses. A surprising number weren't using anything, and the authors discussed the possibility that they had either given up or simply could not successfully wear any other type of lens.

Of those who got sclerals for dry eye or other ocular surface disease, as you might imagine, the vast majority wore either glasses or nothing.

Then there's a sliver of patients - this one's interesting because I suspect it's a growing segment and a group that are being heavily marketed to - who got sclerals apparently as an alternative vision correction form, i.e. for simple refractive error. These ones were relatively evenly split between glasses, soft contacts and gas perms.

Results: Is our vision better?

By and large, our vision is doing great, which is why doctors love sclerals. Of the patients who got lenses specifically for vision reasons, about 75% were experiencing improved visual acuity, with the majority clustered in 1 to 4 lines of improvement. But those who got lenses for dry eye also experienced improved vision. 

Results: How about dryness?

Corneal staining

Corneal staining was the measure used in this study. Of the ocular surface disease patients, 65% had no staining with scleral lens use, but all of those who had staining prior AND did still have staining with sclerals had at least shown an improvement.

On the other hand... 22 patients with corneal irregularity rather than ocular surface disease, who did not have staining prior to scleral lens use, had staining at the study exam, which was concerning. In the discussion section of the study, the authors suggest two possible reasons:

1) That the lenses might be too small and riding the cornea.

2) That the patients might be filling their lenses with the wrong thing. They noted that in a previous study, some providers were recommending filling the lens bowl with anything from preserved saline to multi-purpose solutions to tap water! 

One particular statement in the paper propelled me onto my favorite soapbox....

Even if a provider specifically recommends that a patient use only non-preserved products for this purpose, some patients choose to use preserved solutions to fill their lenses

Yes, and do you know why this happens? Because scleral lenses are complicated, patients are not given sufficient support, doctors don't know where preservative-free salines are sold and pharmacists don't know what scleral lenses are. Patients run out of saline, they go to the drugstore, they don't see what they usually use, so they grab a box of Bausch & Lomb Sensitive Eyes, on the assumption that it's the safe one - often at the specific suggestion of the pharmacist.

Scleral lens patients need careful, painstaking education and support if they are to be safe and successful. Doctors, if you want a safe and successful practice, you need a really thoughtful training program for insertion and removal, including ample time for counseling, and make sure to prepare a nice little sheet listing the products AND where to buy them, then reinforce that at EVERY visit!

Persistent new-user problems in the scleral lens community is what ultimately motivated me to start a YouTube channel (my first two videos are both about preservative free salines) on top of all the other channels I've been using to help educate new patients... we're just not reaching enough of them. I really appreciate that so many optometrists are joining our patients' Facebook group (My Big Fat Scleral Lens) to observe the real-life patient issues that are coming up after the patients go home, because we need all you practitioners to understand how much education and support your patients need to stay safe. 

Anyhoo, back to the study:

Eyedrop usage

On average, those who used drops before sclerals decreased from 3.5 types of drops down to 1 type. One outlier patient who was using 7 types of drops was still using all 7. On the other hand, 7 ocular surface disease patients discontinued topical medications altogether when wearing sclerals. Disappointingly, there is no data on frequency of eyedrop usage, which is a big deal for ocular surface disease patients.

On the other hand, a number of the vision-indication scleral lens users who never used to use drops had to start using drops after they got sclerals. Hmmmm.

How about "adverse events"?

A whopping 42% had some kind of issue reported, but most of the issues were relatively minor. There were no cases of the really scary stuff (e.g. microbial keratitis) though as the authors pointed out, we have to look to longer term studies for the real story.

The most commonly observed problem was conjunctival injection (a/k/a redness).

This was followed by lens handling and application errors. These, incidentally, ought to be preventable in the vast majority of cases if the lens providers are committed to providing sufficient training and support, which are vitally important for scleral lens users. 

Other issues that arose - almost all of them in the visual indication crowd - included prolapse, stromal edema and neovascularization.