Clinicians have been fitting scleral contact lenses for over a century; indeed, this design marked our first opportunity to correct refractive error without spectacle lenses. Their virtues in vision correction and promotion of ocular surface healing have long been known, but several hurdles made the mainstream viability of scleral contact lenses short lived.

The earliest sclerals were made of fragile and potentially harmful glass, which was then succeeded by PMMA—a material that offered poor oxygen transmissibility, leading to the discontinuation of lens wear due to corneal hypoxia. Because these materials required the lenses to be handmade, they were impossible to replicate in the instance of breakage or loss.

Fortunately, the modality has improved in recent years; we now have hyper-oxygen permeable materials, computer-driven lathes and diagnostic imaging to guide fits—making scleral lenses more comfortable and easier to fit than many other options. There is nearly three decades of documentation and hundreds of scientific studies proving the success and benefits of wearing scleral contact lenses.

Thanks to the recent advances in scleral lens designs, patients with irregular corneas and ocular surface disease are now enjoying healthy lens wear and great vision with similar initial comfort to that of a soft contact lens.

However, the rapid advancement of corneal RGP and hydrogel soft lenses (and their silicone hydrogel successors) over the same period relegated sclerals to specialty practices serving niche patient populations. We would argue that this is short-sighted and does a disservice to many patients who might be better served with a scleral design.

Refocusing a Mindset
Over the past three decades, the use of (highly oxygen permeable) scleral lenses for a number of ocular conditions has increased dramatically, and the applications for them continue to grow. Ocular surface disease was the first recognized use for scleral lenses, and remains the only indication currently recognized by Medicare for coverage as a prosthetic device.

Patients with corneal ectasia represent a rapidly growing group of scleral lens wearers. Additionally, scleral lenses are restoring vision to patients with neurotrophic and exposure keratopathies, reducing the need for tarsorrhaphies and corneal transplants.

With each passing year, laboratories continue to improve their lens designs to encompass more visual performance needs. For example, scleral lens technology developments made in just the last decade include front surface toric lenses for residual astigmatism and toric peripheral curves for eyes with greater than average scleral toricity.

A number of laboratories also offer reverse geometry design lenses and multifocal scleral lenses. There is even technology to precisely customize a lens to the specific shape of an individual’s irregular globe. These options allow us to offer customized care for our entire patient population—improving vision, comfort and overall quality of life for habitual and new lens wearers alike.

It’s not just the technology and designs of scleral lenses that continue to evolve, however. We’re now beginning to use more sophisticated fitting techniques to expand the pool of patients who can be considered candidates for scleral contact lenses.

For example, scleral lenses aren’t only for patients with irregular corneas; patients with normal corneas are now considered great candidates—especially when their visual needs exceed the typical parameters of soft lenses.

Scleral lens wear in patients who do not have irregular corneas is becoming so popular that laboratories are designing scleral lenses made specifically to vault normal corneas. Patients with high astigmatism who desire a multifocal option are no longer restricted to corneal gas permeable lenses—even though, in certain cases (e.g., a patient with ocular surface disease, such as dry eye or refractive error), these designs remain a great option for lens wear.

Adding patients with normal eyes to the scleral lens-wearing population has signaled a major shift in philosophy from years past—and it’s continuing to gain popularity. As habitual contact lens wearers reach their forties and contact lens dropout becomes more likely, sclerals can offer us another way to keep patients wearing lenses despite the onset of presbyopia and ocular surface disease that may otherwise be a deterrent.

Overall lens diameter is another aspect of scleral lenses that has seen a significant change. The theory behind lens diameter selection remains the same: the more sagittal depth needed to vault the corneal apex, the larger the lens diameter should be.

What has changed, though, is the range of diameters available for scleral lens designs. Now, diameters come as small as 14.3mm, while still maintaining a full corneal and limbal vault, rather than using a corneoscleral fitting technique.
While this design is not appropriate for all irregular corneas, it has been very successful with normal corneas, and a vault of as little as 100 microns is considered acceptable in many cases.

These smaller-diameter lenses are less intimidating for some patients and clinicians, easier for patients to handle and, in some cases, may be a less expensive option. In these smaller-diameter lenses, the limbal-scleral curvature is mostly regular and has less inter-patient variability near the cornea than the peripheral sclera. As with all scleral designs, limbal clearance must be maintained during lens wear to preserve the health of limbal stem cells.

A final change in fitting technique worth noting is the decline in use of fenestrations—a lens alteration used very selectively now, on a case-by-case basis. We have known for 30 years that fenestrating lenses does not increase oxygen transmission or improve tear exchange in any meaningful way. Fenestrations should only be used for easier removal, due to the suction effect. In very rare cases, fenestration may be used to release CO2 from beneath the lens; however, this is not always successful.

To make the fitting process smoother for practitioners, scleral fitting sets now offer expanded parameters to expedite the process. In addition to numerous base curves, many fitting sets include lenses with different overall diameters, changes to the peripheral curve lifts, different curvatures to contour the limbus and even different specifications in sagittal depth.

New Patients, New Vision
With all these advances in scleral lens parameters and technology, nearly every patient in your office becomes a scleral lens candidate. The most receptive are likely those who experience frustration with their current soft contact lenses—usually due to the modality failing to adequately meet their vision needs.

It’s up to the practitioner to ensure every patient is satisfied with their lenses, and it is acceptable to ask your patient whether or not they are satisfied with their quality of vision. Patients often believe their current lenses are the best option available, so they rarely bother to ask questions regarding new products in the contact lens world. Patients who typically fit this mindset include those with high astigmatism, residual refractive error post-LASIK surgery or presbyopia.

Those who have high astigmatism are especially pleased with scleral lenses, as they can rotate without having an effect on vision. If the astigmatic topography shows limbus-to-limbus toricity, it may extend onto the sclera and produce some lens flexure.

As a practitioner, you’ll see with-the-rule astigmatism on retinoscopy and the patient may comment on vision fluctuation or reduced acuity with a spherical over-refraction. A spherocylindrical over-refraction and keratometry or topography over the lens will provide some insight on how much flexure is occurring.

Typically, increasing the center thickness of the lens by anywhere from 0.05mm to 0.20mm is our first adjustment, but decreasing the overall diameter is another option that may reduce flexure. In our experience, a final option when attempting to decrease flexure is to add toric peripheral curves to the lenses in an effort a better contour to the patient’s sclera.

Post-refractive surgery patients have altered corneal geometry and an elevated likelihood of dry eye; they may struggle with vision issues related to the stability of the fit. The oblate-shaped cornea no longer fits the prolate toric soft lenses, which causes patients to become frustrated with lens movement and rotation. Scleral lenses are an excellent option for these patients because the tear lens corrects for corneal astigmatism and helps with dry eye.

	Table 1. Multifocal Scleral Lenses
	COMPANY	LENS
	Acculens	Maxim Plus
	Acculens	Comfort SL Plus
	Art Optical	So2Clear Progressive
	Advanced Vision Technologies	AVT
	Blanchard	MSD
	Blanchard	One Fit
	Dakota Sciences	So2Clear Progressive
	Essilor	Jupiter Plus
	Metro Optics	So2Clear Progressive
	Lens Dynamics	Dyna Semi-Scleral
	Truform	Digiform Multifocal
	Valley Contax	Stable Near

Occasionally, to maintain an even tear film from limbus to limbus, a reverse geometry lens is needed for an oblate cornea. Many post-LASIK patients want to return to contact lenses when presbyopia becomes a problem. Fortunately, there are a number of well-designed multifocal scleral lens options on the market today. Table 1 lists many examples.

Many well-designed multifocal scleral lenses are on the market today. These lenses are simultaneous vision designs, as these lenses move minimally on the eye. Most designs are center-near, with the exception of the AVT scleral multifocal and Jupiter Plus lenses, which are a center-distance design. The Jupiter Plus lens offers an intermediate-near add, but not full-near add.

Making the Soft-to-Scleral Refit
If, following this review, you’re eager to find opportunities for fitting new patients in scleral lenses, start by considering those with normal corneas who wear soft lenses for astigmatism or presbyopia who complain of fluctuating vision or poor night vision.

To successfully convert our soft lens-wearing patients, we must refit them quickly when problems arise and achieve better results than soft torics or multifocals while maintaining good lens comfort.

First, assess their current frustration level as well as their desire to change modalities and undergo a new fitting procedure. Once the patient has agreed to try new lenses, use revelant anatomical data—their topographies, corneal diameter measurement, palpebral fissure widths—to help select an appropriate lens design.

We’re all aware that scleral lenses provide better initial comfort when compared to smaller diameter corneal GP lenses, but we need to be sure we select an appropriate design to ensure a good fit in our soft contact lens wearers. In doing so, we provide an excellent first experience, ensuring the patient remains excited about the vision potential offered by this new lens design.

The following tips can help with the education and fitting process:

• Lens diameter selection. The overall diameter of the scleral lens is the first decision you’ll have to make. This factor is the primary reason scleral lenses provide more comfort than corneal gas permeable lenses. Diameter is also important because it determines the sagittal depth of the lens. Many patients believe their soft lenses are more comfortable than GP contacts due to the biocompatibility of the material, but we know that it’s actually because they have a larger overall diameter and experience less lid interaction and lens movement.

That is an important point to communicate to patients. The larger lenses sit behind both lids, which reduces the interaction between the eyelid and the lens, and promotes excellent comfort and lens stability. Once patients understand this concept, the notion of wearing “hard” lenses is not nearly as intimidating.

When selecting the diameter, do so based on patient factors such as corneal diameter, the sagittal depth required to vault any corneal irregularity or ocular surface disease, scleral factors (e.g., pinguecula, conjunctival chalasis or toricity) and your personal experience with various lens designs. If the cornea is 12mm or more in overall diameter, you may want to begin with a lens that is at least 14.5mm to 15mm, so it can appropriately and comfortably vault both the central cornea and limbus.

An average palpebral fissure width is about 10mm. If a patient has an average sized cornea with a small to average palpebral fissure width, lenses that are 14mm to 15mm in overall diameter will perform well, and the patient will appreciate how easily the lens can be inserted and removed from the eye.

Larger palpebral fissure widths call for a larger lens diameter to ensure the edges of the lens are tucked behind both lids for good comfort. If your patient notes the lens is “a little uncomfortable,” it is likely due to lid interaction from lift off or movement. Depending on the situation, the lens may need to be made either bigger or smaller to correct this.

• Corneal topography and keratometry readings. There may be no direct relationship between topographical K readings and scleral lens base curve; however, topographical maps provide presumed information about sagittal depth.6 Knowing the shape of the cornea can be the deciding factor in lens design selection.

For example, if the topography shows a moderate to large amount of limbus-to-limbus toricity, one might expect the sclera to have a greater than average amount of toricity as well. In this situation, an appropriate lens design may be one from a lab that can produce toric peripheral curves to match the toric sclera.

For a scenario in which the corneal toricity is only in the central cornea, a lens with toric peripheral curves is not needed. Topographic readings are also very useful in evaluation of post-surgical corneas.

Something Old, Something New
With so many aspects of scleral lenses having evolved in just the past decade, it can be confusing to keep all the information straight. Remember that your lens consultants possess a wealth of knowledge, as do groups like the Scleral Lens Education Society. The introduction of new lens designs means you’ll have to learn new techniques, but the principles of patient communication remain the same.

These lenses are comfortable and provide excellent vision correction. The fitting process does require some patience; sclerals are complex in design and need to be ordered custom to your patient’s eyes.

With clear communication and guidance from your laboratories, the addition of scleral lenses for normal corneas should serve as a healthy boost toward developing relationships and loyalty with your patients for years to come. 

1. Weyns M, et al. Scleral contact lenses as an alternative to tarsorrhaphy. Cornea. 2013 Mar;32(3):359-61.
2. Grey F, et al. Scleral contact lens management of bilateral exposure and neurotrophic keratopathy. Cont Lens Ant Eye. 2012 Dec;35(6):288-91.
3. Rathi VM, et al. Fluid filled scleral contact lens in pediatric patients: challenges and outcome. Cont Lens Ant Eye. 2012 Aug;35(4):189-92.
4. Rosenthal P, Croteau A. Fluid-ventilated, gas-permeable scleral contact lens is an effective option for managing severe ocular surface disease. Eye Cont Lens. 2005 May;31(3):130-4.
5. Visser E, et al. Advantages of Toric Scleral Lenses. Opt and Vis Sc. 2006;83(4):233-236.
6. Schornack M, Patel S. Relationship between corneal topographic indices and scleral lens base curve. Eye Cont Lens. 2010;36(6):330-333.
7. van der Worp E. A Guide to Scleral Lens Fitting. Scleral Lens Education Society; 2010.  
8. Potter, Roxanna. Toric and Multifocal Scleral Lens Options. Cont Lens Spectrum. February 2012.
9. DeNaeyer, Gregory. Today’s Scleral Lens. Review of Optometry. June 2012.
10. Bennett, et al. Contemporary Multifocal Contact Lens Primer. Cont Lens Spectrum. February 2012.