Introduction and Quiz
A scleral lens rests entirely on the sclera and is typically 6 mm or more larger than the horizontal visible iris diameter (HVID). Sclerals provide unmatched comfort and clarity, and have become a great option for patients who were unsuccessful wearing a soft lens. Because the lens bridges the entire cornea, discomfort is not an issue. In fact, the entire cornea is bathed in fluid. For this reason, the pool of potential scleral lens patients has expanded from those with diseased corneas to also include dry eye patients, post-refractive surgery corneas, and those with high corneal cylinder.
Bringing scleral lenses to your practice
Whether you’re a first time business owner or are deciding to fit scleral lenses for the first time, there are some business basics to consider before your first patient is on the schedule.
Here is a list of needed supplies for scleral lens fitting:
- Fitting Set
- DMV: scleral cup and ultra removal or 45 removal
- Inhalation 0.9% solution or LacriPure
- GP cleaner and conditioner samples, H2O2 solutions
- Contact lens dispensing towels
- NaFl strips
- Topographer, Slit Lamp, Radioscope, OCT
When choosing a fitting set, there are a myriad of options on the market. If you are new to scleral lens fitting, your first step is to research your options. You may call consultants, and ask what they recommend for new fitters.
When deciding on a set, it may also be helpful to consider what patients you are looking to fit. Will you work with both normal corneas and diseased corneas? Lack of lens availability in multifocal options may also be important depending on your patient demographics.
Also keep in mind that preservative-free saline is extremely important in scleral fittings, particularly with dry eye patients. The goal of scleral lenses is to bathe the cornea in saline; if the appropriate solution is not used, complications such as mid-day fogging may be a result, so do your research!
When setting your fee schedule, it is helpful to consider insurance reimbursements for scleral lenses. Your fitting fee and the fee for the lenses should be separate charges. The major vision plans, VSP and Eyemed, will reimburse $2500 for medically necessary contacts; however, you must charge your private pay patients the same amount as insurance patients.
At the next stage, when evaluating your fee schedule, remember to consider chair costs (including staff time). The average scleral lens evaluation requires changing the lenses 1.5x, but there will be challenging patients who will require more lens exchanges and chair time. Scleral lenses also have a cost per lens and many upgrades are extra. For example, if you think wetting could be a problem, you may consider Hydrapeg, but that can be an added cost of $30-40. If there is the possibility of residual cylinder or scleral irregularity requiring a toric, this add-on can also lead to extra cost. A proper fee schedule can be highly profitable for your practice.
When billing medical contacts, it’s very important to document properly. I recommend visiting each of the insurance plans you take, and print off the medically necessary contact fitting requirements and patient clinical guidelines. Double check that your electronic medical system allows for documentation for each of the requirements, and if not, edit your templates accordingly. Insurance companies are known for taking a second look at billed medical contact lenses and fittings, so you have to be diligent.
Your staff must be able to identify potential candidates, properly bill, and handle lens insertion, removal, and cleaning. It’s important that each member of your team is able to identify potential scleral lens candidates, from the staff member who answers the phone to your technicians.
Candidates for sclerals can include: high myopes, high corneal astigmats, dry eye patients, keratoconics, post-refractive surgery patients, post-transplant patients, and patients with any type of corneal irregularity or scarring. Make sure each member is also familiar with the insertion and removal process as well as how each patient should clean the lens in order to answer calls from patients.
As a new scleral lens fitter, I was not sure where to look to better understand how to fit a scleral lens. A quick google search revealed resources such as the scleral lens society, and a number of manufacturer websites with fitting guides. The most helpful resource I found was this guide produced by Art Optical. This guide is the perfect place to start for a practitioner.
After an understanding of the basics, I called my distributor, ABB, and asked the consultants for their recommendations.
From there, I watched several videos on YouTube to get a sense of how to fit those particular lenses and gain a better understanding of each set’s strengths and weaknesses. ABB was also able to provide me with a trial set for $30 in order to get my feet wet as opposed to buying a fitting set which can cost $400-500. I highly recommend this option. It allows you to gain an understanding of the process without a big initial investment.
Social media implementation
Whether you’re beginning a new practice or implementing sclerals into an existing practice, it’s important that potential patients are able to identify your practice as one to meet their needs. Identification words such as keratoconus, corneal thinning, and dry eye will make your website more SEO friendly and therefore easier to find online. Many scleral lens experts recommend blogging on scleral lenses. Once the word is out, as always, word of mouth is the best referral source!
Although optometrists have been fitting scleral lenses for years, the expansion of fitting set options has allowed us to fit more patients than ever before. Between scleral lens fitting facebook groups and access to fitting consultants, fitting scleral lenses is much easier than ever before!
The basics of fitting scleral lenses
When fitting scleral lenses, each fitting set can be a little different. Each set can vary at any stage, from picking a starting lens to the number of zones. As always, consultants can be very useful in helping you to manipulate your particular lens of choice. I have looked at a number of fitting sets, and have combined the basics in order to give you a step-by-step guide to fitting scleral lenses as a new fitter.
Pick your initial lens size from the trial set.
Most lenses look at either keratometer readings or horizontal visible iris diameter. In sets that use keratometry readings, the trial set may use an average k-reading or modification of a keratometry reading. Horizontal visible iris diameter is used in order to predict the initial diameter of the lens. Scleral lenses can be ordered in diameters up to 20mm, but most patients can be fit with a 15.0-17.0 mm lens.
Fitting sets may come with small diameter lens, which may be helpful for patients with normal corneas or for those with small fissures and more brow bone involvement. Larger diameter lenses are needed to bridge over entire corneas which can be necessary when working with patients with corneal grafts, keratoconus, or keratoglobus. When in doubt, it’s recommended to start with a larger diameter lens.
Chose a sagittal depth.
There are two ways to determine possible starting sagittal depth. The first is to look at the cornea from the side and approximate whether you need a low, medium, or high sagittal depth. In general, choose a low sagittal depth in the range of 3800-4000 μm for post-refractive and normal corneas. A medium sagittal of 4200-4400 μm should be chosen for pellucid marginal degeneration and early to moderate keratoconus. High sags of 4800-5400μm should be chosen for advanced keratoconus and bulging grafts. When in doubt, choose a lens with a higher sag—you must avoid corneal touch!
Evaluate the fit using an optic section and/ or anterior segment OCT if available.
Evaluate each zone of the lenses.
Depending upon the brand of scleral lens, there may be 3-4 zones. (If you are just beginning to fit sclerals, I would suggest starting with a brand that has only 3 zones.) Assess the lens from central to peripheral cornea. Use a Wratten filter with blue light for easy viewing.
Zone 1: Corneal Zone
The first zone to evaluate is the corneal zone. Since you’ll know the size of your trial lens, use an optic section and compare the clearance area width to the width of the lens. Most trial lenses are around 300-350 microns, so you are looking for a 1-to-1 ratio. Be sure to evaluate all the way out to the limbus across the entire cornea.
Zone 2: Limbal Zone
If there’s bearing at the limbus, you must increase the limbal clearance. Ideally, you should have 100 μm. Scleral lenses should bridge this area to provide good comfort. This area will be modified differently depending on your fitting set.
Zone 3: Landing Zone
Evaluate the landing zone area in all four gazes. Make sure there is not any blanching of blood vessels or impingement. If any blanching is occurring, you need to increase edge lift.
If you are seeing an uneven amount of fluorescein in opposite meridians, a back toric may need to be ordered. We know research shows that most patients have toric sclerals, meaning the sclera of the eye is not symmetric in all meridians. A lens can be made with a back toric if not in the fitting set to improve the fitting on the cornea. Some fitting sets have all lenses made with a back toric. If you aren’t sure, contact consultation at your lab.
Ask the patient how the lens feels on their eye. This may help you to identify where there isn’t enough clearance and the lens is settling on the cornea.
Note: If there are any bubbles, the lens must be removed and reapplied. If there is any touch, immediately remove the lens and increase the sagittal depth of the lens.
Fitting Tip: Let the lenses sit on the eye for 25-30 minutes before evaluating them. This can provide you with more information on the fit. Most scleral lenses may settle 100-200 microns after 30 mins, and you may have to change sagittal depth depending on that change.
For examples of proper clearance and fit, I would recommend reviewing the powerpoint by Dr. Anita Gulmiri here.
Over-refraction should be done for both sphere and cylinder elements of the refraction. If there is cylinder remaining, the lens may be flexing. The lab can make changes, including adding a front toric to the lens.
Choose a lens material and order
Lenses may be available in several dks. Depending on the patient’s condition that you are treating such as dry eye or transplant, you may elect to increase the dk.
Once you start fitting lenses
When it comes to fitting sclerals, most doctors choose to get comfortable with 1-3 fittings sets in order to improve your comfort with the fitting set and give yourself the most options to fit patients.
Choose an initial set with the following options to cover your bases, and for simplicity. The following are recommended guidelines for lens set selection:
- Fits regular and irregular corneas
- Fitting set of choice includes ability to fit both regular/ irregular corneas
- If the set is only irregular, you will have difficulty with dry eye patients
- Includes back toric lenses
- Human scleras are toric, so back toric lenses should be a part of the set
- Fewer zones to change
- Ideally, the set should have fewer zones to change (3 vs 4)
- Individually alterable zones
- Easier fitting sets are ones in which all zones can be altered individually of one another
As always, consultation at your lab can be very helpful in picking the best set for you. I would tell them you are a scleral lens fitting newbie, and ask which set may be the easiest to begin with. My lab recommended the Jupiter fitting set, and let me borrow a loaner fitting set for a minimum fee. This is extremely beneficial for a newbie to get started without the initial investment of the cost of a fitting set at $400-500. I’ve also found certain companies such as Synergeyes will deduct the cost of your first several fits from the cost of the fitting set. So book all your potential scleral lens patients in the first 90 days after receiving your fitting set to best reduce your cost!
Prior to actually putting a lens on the eye, I would recommend 10-15 hours of research on the types of available lenses, possible complications, and how to manage patients with specific ocular conditions.
Common scleral lens complications
As a relatively new scleral lens fitter, as with any contact lens, the most concerning factor to doctors is potential scleral lens complications. I’ve compiled a quick and easy reference to some of the most common and how to easily solve the problem you may have with your patients. At initial lens fitting, patients should be evaluated after 25-30 mins on the eye, and wearers should be evaluated every 6 months in order to avoid complications andtrack patient compliance.
Lens fogging is a condition that occurs most commonly in patients with atopic disease or dry eye. Fogging is a milky and/or debris buildup in the reservoir behind the lens. This can be worse for a new lens wearer, and decrease as the patient gets more familiar with the lens and may not be removing as often. Lens fogging may have an effect on both comfort and vision. According to studies done by the University of Houston, smaller scleral lenses have less problem with fogging, and this seems to correlate to an increase in lens fogging with corneal clearance.
How do I fix it?
The first step is to have the patient remove and manually clean the lens. The second step would be to make sure the patient is using a non-preservative care system. The last step may to change the lens size or fit. In patients with ocular surface disease, treating the meibomian gland function is imperative to prevent lens fogging.
Blanching of the conjunctiva is important to look for when evaluating the landing zone of scleral lenses. Blanching is localized pressure on the conjunctiva in one area or circumcorneal. If blanching is only in one area, it may be due to an irregular scleral shape. If circumcorneal, the lens is too tight. Blanching should be observed in each direction because decentered lenses appear different than straight on gaze.
How do I fix it?
Circumcorneal blanching is due to a suboptimal landing zone, which can be either too tight or too loose. If the entire area is blanched, increasing the landing zone area (increasing lens diameter) may be helpful.
If blanching is localized, it may be due to a pinguecula. This may be fixed by loosening the periphery or changing the lens to fit an asymmetric sclera. The scleral lens should be ordered with a back surface toric. You may also be able to notch the lens in the area of the pinguecula.
Impingement is when the lens is pinching the conjunctiva in one area. This is the result of improper edge lift, and may cause conjunctival staining after the lens is removed. The lens is too tight and may be obstructing blood flow to large vessels.
How do I fix it?
Easy fix! Change the landing zone. If untreated, impingement can cause conjunctiva hypertrophy. If only in one area, an asymmetric lens design may need to be ordered.
If you are like me, applying lenses without air bubbles is one of the most frustrating parts of fitting scleral lenses. Air bubbles are due to poor lens application. They can also be present in the Limbal zone of the lens if the lens is not close enough to the eye. Air bubbles can lead to poor vision and comfort, and areas of dryness on the cornea. Bubble in the Limbal and landing zone area may be due to excessive clearance. If the landing zone and edge lift are not sufficiently close to the cornea, bubble called “Frothing” can result.
How do I fix it?
Patients should be taught proper insertion techniques. Upon lens insertion, the patients chin should be tucked toward their chest and their eyes parallel to the ground. The lens should be applied at a 90 degree angle. It’s best to release both the upper and lower lids once the lens has been applied for proper placement.
If the bubbles appear towards the periphery of the lens, the Limbal angle of fit and/or edge lift may need to be changed. Your consultants may be best at helping you with your particular scleral lens design
This is a condition caused by ocular surface disease or dry eye. Under the slit lamp, you are able to see where the lens is dry in patchy areas.
How do I fix it?
First check for any underlying conditions such as Meibomian gland dysfunction or Giant
Papillary conjunctivitis. If those are absent, cleaning the front surface of the lens with a cotton swab may be effective. Preservative free lens cleaning systems are best for these patients. Most recently, Hydra-PEG may be added to the lens surface to improve poor wettability. I order this on RGP patients already.
Lens adhesion, although rare, can be a complication in a patient who wears their lenses for extended periods of time. Lens adhesion will cause significant discomfort, and could cause significant problems in patients with fragile corneas. Adherence can occur more often when the lens creates a seal off and/or in dry eye patients. Check the fit for increased pressure on the conjunctiva or if there is increased lens flexure.
How do I fix it?
Change the lens fit. Most likely changing the diameter to a larger lens to increase corneal clearance or flatten landing zones.
Corneal edema is a rare complication with scleral lenses, but care must be taken especially in post-transplant/graft patients. High dk materials, reduced lens thickness, and minimal lens clearance are key to preventing corneal edema. Care must be taken to ensure the lens in vaulting the cornea completely. If there is any touch, edema can be a complication. Scleral lenses can sink from 100-200 microns after hours of wear so initial vault should be between 300-350 microns. Flexure of the lens may also result in edema.
How do I fix it?
Re-evaluate the central clearance. The University of Montreal conducted a study to determine ideal scleral lens parameters in order to prevent corneal edema. They determined hypoxia could be avoided by assessing dk/t, clearance and a reasonable lens thickness. Choose a lens with a higher dk. The dk/t should be at least 125. Initial lens thickness should be around 250 microns. Ideal corneal clearance should be 250 microns.
Conclusion and References
Sclerals are an important addition both for financial reasons and as a solution to complicated patient cases. Your office can attract and help a new subset of patients who would benefit greatly from this impressive technology. Hopefully this quick reference will help solve any complications that will arise and give a new fitter confidence to navigate the world of complicated corneas and scleral lenses.