Since the mid 2000s, no other type of contact lens has seen more growth and excitement than scleral lenses.  In last year's annual contact lens trend report from Contact Lens Spectrum, doctors reported fitting scleral contact lenses more than both rigid gas permeable toric and multifocal lenses, with sclerals making up 3% of all contact lenses being fit (including soft, hybrids, and RGPs) in 2015. Why sclerals?  The larger contact lens size makes for more stable vision and improved comfort over traditional small diameter RGPs, ideal for irregular corneas, high astigmatism, and conditions like keratoconus.  Breaking into the world of fitting scleral contact lenses can have a sharp learning curve, so I strongly recommend attending courses like those offered from the Scleral Lens Education Society, Blanchard, and Vision By Design.  Once you feel ready to get started, the fitting set arrives and it's time to put lenses on your patient.  What to do? We're talking initial lens selection and evaluation in today's post!

Choosing the Right Diameter
There are a ton of scleral contact lens options out there, with common diameters ranging from as small as 14.3 mm to over 18 mm.  The truth is, lens diameter selection depends on your patient. Smaller lenses are typically easier to fit, especially on corneas with lower amounts of irregularity. Advantages of smaller diameter lenses include:

• better oxygen permeability (smaller lenses can be fit with less central vault, meaning better oxygen exchange through the tear film)
• easier patient handling
• easier removal (smaller lenses will fit flatter in general so will have less suction with removal)
• avoiding scleral toricity  --- The white of the eye (sclera) tends to have more of it's own innate astigmatism as you venture more peripherally from the limbus.  The larger the scleral lens you are fitting, the more likely you'll have to use  toric peripheral curves to achieve a good fit.
• minimize fogging -- larger lenses tend to have more issues with lens fogging, theoretically because they are interacting more with the conjunctival goblet cells that produce mucin

Proper lens diameter should clear the limbus by 2-3mm on either side.  The lens above shows inferior fenestration which isn't used by many doctors these days -- at one point fenestrations were popular to improve oxygen transmission.  These days, doctors change their fit to improve oxygen transmission by minimizing their central and limbal vault (see below).  via

How do you assess central clearance?  Fill the lens with nonpreserved saline and a swirl of NaFl dye.  You can judge the central clearance of the lens by comparing the tear film thickness (green above due to the NaFl dye) to the corneal thickness on your slit beam.  Knowing the average corneal thickness is about 550 microns, you have a predictable judge of  tear clearance.  In the picture above, the tear clearance is almost as thick as the corneal clearance, so I would grade this around 450- 500 microns of clearance.  This is TOO MUCH!! Photo via

Of course, if you have an OCT you can image the exact amount of corneal clearance with an anterior segment scan. via

Want the perfect limbal clearance? You should just see a faint hint of NaFL dye right at the limbus with the perfect fit of 30-40 microns.  Of course, you could also use an OCT to assess this area if you have access! via

If the edge of the lens is too tight, you'll see blanching of the conjunctival vessels in as little as half an hour.  This will cause severe discomfort and binding of the lens when the patient attempts removal.  Before sending the lens home with a patient, make sure you check the edge carefully to ensure that the conjunctival vessels are passing underneath the edge of the lens freely, without any pinching or thinning. via

The last time a medication was approved for the treatment of dry eye syndrome? October 2003.  That medication was the blockbuster Restasis, still commanding the dry eye marketplace 13 years later. Over those 13 years, we've learned a lot more about dry eye and the 16 million Americans that are diagnosed and treated for it every year.  They suffer from symptoms like burning, watering, redness, blurry vision, and tired eyes. For many, even the best medical care available on the market is not enough to overcome their discomfort.  That's why the world is so excited for a new medication on the market.  Shire's Xiidra was FDA approved on July 12th for the treatment of the signs and symptoms of dry eye disease (Restasis is FDA approved to treat the signs of dry eye disease only). Slated to become commercially available this fall, there's still a lot about Xiidra that patients and eyecare providers don't know. We don't know the cost, we don't know exactly how patients will respond in our offices, we don't know how Xiidra will compete with Restasis, and we don't know how insurance coverage will look.  Here's what we do know so far:

via

What It Is:
Xiidra (lifitegrast 5%) is a non-steroidal anti-inflammatory eye drop, treating dry eye by disrupting the inflammatory cascade responsible for much of the discomfort and ocular surface changes associated with dry eye disease. It specifically targets intracellular adhesion molecule 1 (ICAM-1); Xiidra binds to proteins on the surface of white blood cells (leukocytes) where ICAM-1 would typically bind, thus blocking ICAM-1 from being able to attach and signal the inflammatory cascade. When ICAM-1 molecules bind to leukocytes, they signal T-cells (the body's main inflammatory cell unit) to the area.  Xiidra prevents this binding, and thus T-cells aren't signaled to migrat to the ocular tissue.  What does blocking the inflammatory cascade mean to you? Inflammation is what makes dry eye so miserable - redness, burning, and surface cell damage (called superficial punctate keratitis -- basically dried out corneal cells sloughing off the cornea creating symptoms like sharp pain and blurry vision).

Superficial punctate keratisis: when corneal surface epithelial cells dry out, the cell wall break and they begin to slough off.  The process can cause you to feel sharp, shooting pain and chronic discomfort and visual fluctuations. via

What It Does: 
In the clinical trials that earned Xiidra FDA approval, over 1000 people with dry eye disease were treated with Xiidra over the course of 12 weeks and the results were compared to placebo treatment. Patients being treated with Xiidra showed statistically significant improvement at Week 6 and Week 12 as compared to those on placebo eye drops in both the signs and symptoms of dry eye, as measured by a subjective symptom scoring questionnaire called the Eye Dryness Score (EDS) and inferior corneal staining (see superficial punctate keratitis above).

How It's Used:

• Like Restasis, Xiidra is dosed 1 drop in both eyes 2 times a day.  
• Clinical trials suggest that Xiidra will begin improving both the signs and symptoms of dry eye as early as 6 weeks into treatment, much faster than Restasis whose clinical trials showed improvement in signs of dry eye (judged by Shirmer score) at 6 months versus placebo.  
• Xiidra and Restasis both target the inflammatory cascade, but they do not target the same molecules so there is no scientific data that suggests they could not be used in combination. 
• Xiidra is pregnancy category C (meaning it was not tested for safety)
• Xiidra is approved for ages 17 and up
• Xiidra is not approved for use with contact lenses; you must remove contact lenses before insertion and wait 15 minutes before reinserting them.
• Side effects of Xiidra: 
• 5-25% of users experienced burning with drop insertion, altered or bad taste (called dysguesia), and blurry vision after insertion
• 1-5% of users reported adverse reactions of ocular redness, headache, watering eyes, runny nose, and ocular discharge

Does your desk have stacks of optometry magazines dating back to your graduation year that you insist you'll read -- eventually? Is your email full of unopened blasts from your favorite digital optometry subscriptions?  And (the horror!) you haven't even gotten around to reading the latest Eyedolatry post yet? We live busy lives, and between patient care and families at home, most ODs are completely spent when it comes to spending precious free time reading about optometry.  So instead of reading a full article, wouldn't it be great to get just short, to the point little blurbs about the most exam-room worthy topics of discussion from the past week? Stories curated by an OD that will impact how you practice and what you can tell your patients about new innovations?  This beautifully simple idea is from Dr. Jackie Garlich, the mastermind behind 20/20 Glance.

With all the glories of long days, barbecues, and beach trips full upon us, sunglasses are practically a wardrobe staple for most Americans.  If they aren't, let me be the first to say you are definitely doing it wrong.  But for many, even when you are actively trying to protect your eyes from sun damage (which includes yellowing growths on the eyes and the risk of blindness as you age), you may be unwittingly putting your eyes at risk by investing in the wrong sunglasses.  Not all sunglasses are created equal, so avoid  these common mistakes to make sure you are actually wearing glasses that give you true UV protection: