Specialty Lenses and Corneal Disease

Specialty contact lenses (ie, rigid gas permeable [RGP] lenses, scleral lenses, and hybrid lenses) are a great option for patients who cannot refract well or see well out of spectacles. The goal behind fitting specialty lenses is twofold: 1) not to cause additional harm or compromise to the patient’s cornea, and 2) to provide better vision. This article offers some direction on which patients specialty lenses work best for, as well as lens fitting, patient considerations, and more.

GENERAL SPECIALTY LENS FITTING

When you have a patient with confirmed corneal disease in your chair, first, find out their goal. Some patients do not want to wear contact lenses and can get good vision simply with an updated refraction. But if this is not possible and the patient desires better vision, then specialty contact lenses may be the best option for them.

Next, I assess the patient’s corneal health. (Some corneas are not ready for specialty lens wear, such as those with inappropriate endothelial cell count or severe ocular surface disease). To reiterate, we never want to prescribe a lens that could potentially worsen the condition of the cornea. For example, if a patient has Fuchs dystrophy with corneal edema, I would proceed with caution when fitting them with a contact lens that could potentially worsen the edema. For a patient with keratoconus and a very thin cornea, we want to make sure the chosen lens does not bear down on the cornea and compromise it further (Figure 1). Young patients with myopia are a totally separate consideration (see Contact Lens Fitting for Myopes).

SELECTING THE APPROPRIATE LENS

RGP Lenses

These were the original specialty contact lens, where everything stemmed from. They aren’t as popular as they used to be, but they still definitely have a place in specialty care. I use them for patients who have mild to moderate cases of corneal irregularity (eg, those with mild keratoconus). Additionally, for patients who may have budgetary concerns, RGPs are the most economical of the three specialty lens types, costing significantly less than scleral or hybrid lenses.

Scleral Lenses

Scleral lenses are becoming the standard of care for most irregular corneas. These lenses provide a variety of lens options to create the best vision and comfort to patients. For example, the lens can be customized to accommodate the most complex ocular surface, and lens optics can include torics, multifocals, and higher-order aberration correction for some designs.

Hybrid Lenses

Hybrid lenses provide the best of both worlds: the comfort of soft lenses and the vision of rigid lenses (Figure 2). Thus, they are a great option for patients who are accustomed to wearing soft lenses but need a rigid lens to achieve the best vision, or for patients who struggle with the insertion and removal process that comes with scleral lens wear.

FITTING SPECIFICS

Lenses are typically fit either diagnostically (with a fitting set in the office based on topography) or empirically (using topography and a refraction that get sent to a lab, then a custom lens comes back for the patient). There’s a lot of power in the diagnostic fitting process because right then and there the patient gets an idea of what things might be like, but it’s actually more efficient to fit empirically, and I prefer this way of fitting when possible because the very first lens the patient puts on is mostly custom fit to their eye.

RPGs and hybrid lenses can be fit either diagnostically or empirically, although most practitioners seem to be moving more toward empirical fitting, sending topographies and refractions to the lab, and then custom making a lens. I always empirically fit RGP and hybrid lenses.

There’s a few different ways to fit scleral lenses:

• Diagnostically, with a fitting set, finding a lens that fits well, doing an overrefraction, etc.
• With the scleral profilometer, or scleral topographer, which is basically a scan of the entire ocular surface that is sent to a lab. The lab then sends you a trial lens that usually fits well and provides good vision. That’s kind of the wave of the future and how a lot of practitioners are fitting. The only limitation is that you have to buy a profilometer, so it involves an expense, but it can save some chair time
• Using an impression-based lens to make a mold of the eye, which you send to the lab and they print a custom lens for the eye.

THE PATIENT COMPONENT

Patient Goals

Many of my patients are defeated because they’ve lost their independence and they’re trying to get it back. They want to be able to drive safely at night. Sometimes it can be challenging as a practitioner because patients come in with lofty goals, and many times we can achieve them, but sometimes we can’t, so we have to temper their expectations and goals.

Age

We have many older patients with corneal dystrophies and degenerations who could benefit from a specialty contact lens, but dexterity issues caused by rheumatoid arthritis or another ailment prevent them from successful wear. There are some tools and strategies available that can help get a motivated patient into a specialty lens.

Education

My team and staff members have concentrated time with each patient to teach them how to insert, remove, clean, and store their lenses. Then we send the patient home with a document I put together that restates everything my technician discussed with them. (We also have a QR code the patient can scan that offers a video version of what we did in the office and goes over everything in the written document). We try to leave no room for mistakes, and we provide three different opportunities to learn, because patients are not going to remember everything you tell them on day 1.

Follow-Up

Typically, on day 1, I dispense the lens. Even if the patient reports some discomfort or lens awareness, I ask them to take the lens home for a week or 2 because those little fitting nuances that are there in the beginning almost always settle out.

I generally have patients come back at the 2-week mark to troubleshoot any potential issues, but if they are anxious or I sense they need some handholding, I have them return after 1 week, then schedule them back every 2 weeks until we are all happy with the way the lens fits. Once we get to a lens that everyone feels good about, I’ll push them out for a month. At this visit, maybe another 30% of patients need an additional change or tweak. However, most patients are good at this point, so I schedule to see them back every 6 months to make sure that they are doing okay. I always leave a window open for them to see me at any time.

Most manufacturers offer a 90- to 120-day warranty period, and I let patients know there is a finite amount of time to get the lens fit right. I tell them they can see me as often as they need to during that timeframe. Most of the time it follows that protocol, but sometimes I’m seeing patients every 2 to 3 weeks during the entire fitting process because their eyes are that complicated.

Complaints

If the patient returns 2 weeks after the initial lens fitting and is having issues, I ask them to describe their issues and I address them accordingly. I lean on technology to help me troubleshoot—I have an OCT in my practice and using the anterior segment function can be helpful when assessing the lens fit. Sometimes I’ll send those scans off to the lab, along with the information from the patient and ask for a consultation. The consultants at the labs know the lenses better than we do, and I’ve learned most of what I know by fitting, dispensing, troubleshooting, and leaning on those consultants.

Fitting failures are rare, and typically happen when the patient’s eye cannot tolerate lenses or the patient can’t master insertion and removal. In such cases, we work with patients as much as we can to help them learn insertion techniques. Sometimes we have to use different devices and stands that hold lenses so patients can focus on opening their lids. Every now and then we’ll have a patient who just cannot adapt to, say, an RGP lens. We will then need to put them in a scleral lens, but sometimes patients can’t adapt to a scleral lens; so I will put them in a hybrid lens or vice versa. I am committed. If a patient wants to be in a lens, I am going to find a lens that works for them.

LOOKING DEEPER

We need to do a thorough assessment of the patient’s entire eye, because those who are 50 years of age or older could have cataracts that also affect their vision. We also need to look at the retina to make sure they don’t have macular degeneration or any other retinal disease that would temper what we can do. So, we have to assess the eye from front to back to set realistic expectations.