The U.S. GP lens market at the start of the year 2020 looked much the same as it did leading into 2019. An estimated 11% of contact lens fits and refits in 2019 were with some form of rigid lens, in comparison to 11.4% from the previous year.¹ Internationally, this number was a little higher for GP lenses—including those used for overnight orthokeratology (OOK)—in 2019 at 13% (10% non-OOK, 3% OOK).² This represents a large increase from the previous year, in which the total number of GP lens fits internationally was 9%.³

Data provided by Robert W. Baird & Co. (Jeff Johnson, OD, CFA, managing director, senior research analyst) indicates that the estimated size of the GP market in 2020, which includes OOK, scleral, and corneal GP lenses, will slightly top $400 million. Scleral and OOK have been growing at a rate of about 10% to 15%, respectively, primarily driven by China, whereas corneal GPs are declining in single digits. Dr. Johnson also emphasized that COVID-19 has obviously had an impact.

This article will report information throughout from Contact Lens Spectrum’s (CLS) annual GP Prescribing Survey to its readership. When asked whether they prescribe GP lenses in their practice, an encouraging 98% responded that they do. Similar to last year, advances in scleral lens designs and applications, the increasing interest in myopia control in general, and ongoing improvements in multifocal and hybrid designs appear to be benefitting the GP market. However, the COVID-19 pandemic has resulted in reduced prescribing and manufacturing of these designs due to office closures or limited access, especially at the start of the pandemic before new manufacturing and practice protocols were in place. During the initial shelter-in-place orders, eyecare professionals (ECPs) and manufacturing laboratories often incorporated temporary changes to their established policies to help those GP wearers in need of lenses. These changes included direct shipment of lenses to patients, extended warranties, and extended length of prescription.⁴

Figure 1 shows the types of GP lenses prescribed by respondents of the GP Prescribing Survey. Conventional corneal designs continue to be the primary GP application at 36%, followed by sclerals (28%), corneal reshaping/OOK (12%) and then both non-scleral lens designs for irregular corneas and multifocals (11%), torics (8%) and hybrids (6%). Of note is that when comparing results from this year to two years ago, corneal GPs have decreased from 43% in 2018 to 36% in 2020, and sclerals have increased from 23% in 2018 to 28% in 2020.⁵

The GP Prescribing Survey also asked readers about their preferred method of fitting­—diagnostic versus empirical—with regard to seven different categories of lenses (Table 1). In many cases, empirical fitting predominated, which points to the continual increase in the quality and reproducibility of GP lenses. This is important, as soft lens patients are accustomed to achieving acceptable vision during the initial fitting; therefore, with GP wearers, it is advantageous to have a good visual experience with the initial lens application. Empirical fitting dominates for spherical, toric, and multifocal lens designs. With the ongoing advancements in OOK and hybrid lenses, empirical fitting should continue to increase with these designs. In addition, while it is challenging to fit an irregular cornea based on traditional keratometry and refraction information, empirical fitting should increase—notably with scleral lenses—as scleral profilometry continues to increase in use.

WHAT ARE THE MOST IMPORTANT DEVELOPMENTS IN THE LAST YEAR?

We surveyed the prominent specialty contact lens experts of the GP Lens Institute (GPLI) Advisory Board regarding what they believe was the most important new development in GP lenses in the last 12 months. Topping the list were 1) scleral profilometry and profilometry-designed scleral lenses; 2) the introduction of a 200-Dk material; and 3) the increasing availability (and use) of scleral back-surface toric haptics as well as quadrant-specific and other design innovations such as the correction of high-order aberrations. Tied for fourth in responses were advancements in OOK lens designs and the introduction of new standards in the disinfection of reusable diagnostic contact lenses, notably scleral diagnostic lenses. The latter was a collaborative effort between the American Optometric Association Contact Lens & Cornea Section and the American Academy of Optometry’s Section on Cornea, Contact Lenses and Refractive Technologies.⁶ The sidebar on p. 34 shows the Advisory Board’s predictions for the future.

Scleral lens designs have a greater center thickness accompanied by a thicker tear layer that make a hyper-permeable lens material necessary. A GP lens material with a Dk of 180 was introduced to the market last year. A 200-Dk material recently was awarded a patent, received 510(k) clearance from the U.S. Food and Drug Administration (FDA), and entered the market.

SCLERAL LENS DEVELOPMENTS

As previously mentioned, scleral lens use continues to increase and may soon rival corneal lenses as the primary GP lens design prescribed. Figure 2 shows the data on scleral lens use according to our CLS GP Prescribing Survey. A total of 44% indicated that scleral lens use in their practice has increased (9% increased greatly; 35% increased slightly) as compared to 2019, in which a total of 37% reported an increase in scleral lens prescribing. Likewise, the “Not Applicable” response (i.e., not prescribing scleral lenses) decreased from 27% to 19%.

Recent studies have demonstrated the benefits of scleral lenses, including the impact that they can have on wearers’ quality of life. Ling et al evaluated the impact of contact lens wear on the rate of corneal transplantation for individuals who have keratoconus.⁷ They evaluated the records of more than 2,800 eyes, the majority of which had been fit at least six years prior with corneal or scleral GP lenses. They concluded that patients who had been fit into scleral or corneal GP lenses had only about one-fifth the risk of undergoing a corneal transplant. The obvious benefit of scleral over corneal GP lenses is comfort, and that in itself can prevent some patients from undergoing some form of keratoplasty.

This was confirmed in a randomized controlled trial of corneal versus scleral GP lenses for keratoconus and other ectatic corneal disorders. The authors concluded that significantly better comfort resulted with scleral lenses as compared to corneal GPs.⁸ In addition, Porcar et al recently provided an excellent overview of the benefits of small-diameter (< 15mm) scleral lenses, specifically in the treatment of corneal irregularities and ocular surface disease.⁹

An area of potential concern in recent years with scleral lens wear is corneal hypoxia due to a combination of the lens thicknesses required and the thickness of the tear film, the latter often ranging from 100-to-300+ microns. This was the focus of a recent study by Giasson et al evaluating the incidence of corneal endothelial blebs induced in scleral lens wearers.¹⁰ Patients were fitted with two scleral lenses that had targeted clearances of 200 and 400 microns. Following short-term wear of each lens, the scleral lenses fitted with a clearance of 400 microns induced significantly more blebs compared to the lenses fitted with a clearance of 200 microns, suggesting reduced oxygen and/or increased carbon dioxide levels under the higher-clearance lenses.

MYOPIA MANAGEMENT

The area of myopia management is, of course, exploding in 2020. The first lens design to receive FDA approval for this indication launched earlier this year and has helped to boost interest in this modality from practitioners and patients alike. The heightened interest and need for clinical information spurred the inception of the Global Myopia Symposium (GMS), a conference devoted exclusively to the topic of myopia and its management, which took place virtually last month; highlights from the inaugural program will appear in a future feature article in CLS.

Responses from our reader survey demonstrate an increasing trend toward soft multifocals as the most popular myopia management method in practice, used by 55% of those responding (as compared to 46% in 2019), although OOK remains popular at 44% (as compared to 42% in 2019), and a much higher percentage (32% in 2020 as compared to 24% in 2019) have incorporated some form of atropine into their myopia management regimen (Figure 3, multiple responses permitted).

Although soft lenses have predominated at an increasing rate in recent years, interest in OOK also appears to be increasing as interest in myopia management begins to greatly escalate. According to an excellent review on this topic by Bullimore and Johnson,¹¹ peer-reviewed publications on OOK have increased dramatically in the last five-to-seven years. Several recent studies have compared OOK and atropine as to their effect on myopia progression. In one study, 142 myopic children were administered 0.02% atropine versus a group of 105 children who were prescribed OOK, and the results were compared after a two-year period.¹² The researchers found that OOK appeared to be a better method for controlling axial length elongation in children who had higher myopia.

Tan reported on a one-year, controlled, single-masked clinical trial in which subjects were randomized into one of two treatment groups: 1) AOK, consisting of nightly 0.01% atropine combined with OOK; or 2) OOK alone.¹³ The results indicated that axial elongation was significantly slowed in the AOK group (versus OOK) during the first six months, but there was no difference in progression during the second six months. It was postulated that the enhanced effect of the combination could result from an enlarged photopic pupil size, increased exposure of relative myopic peripheral defocus on the retina, and/or elevated total higher-order aberrations in OOK-treated eyes.

Finally, in a study that essentially confirmed a previous report,¹⁴ Chen et al compared four separate OOK lens designs on their ability to control myopia progression.¹⁵ They found no significant difference among these designs.

GP MULTIFOCALS

GP multifocals continue to be a viable modality for the contact lens correction of presbyopia. Table 2 shows the CLS GP Prescribing Survey results for the various GP multifocal types and their use. Aspheric multifocals—including front-surface only, back-surface only, or a combination—continue to dominate, with segmented, translating lenses representing the second most preferred go-to GP design. The preferences for both of these designs are essentially identical to 2019. Scleral multifocals have increased as a go-to design, while both concentric and hybrid designs have decreased compared to last year. However, a new center-distance hybrid design for emerging presbyopes was added to the family of center-near hybrid multifocal designs.

An important advancement in aspheric, concentric, and aspheric-concentric combination lenses is the ability to provide a variety of effective center-distance zone sizes to accommodate variance in add power as well as in pupil size. A recent study used five different center-distance zone sizes, with the results showing that the two smallest zone sizes favored near vision; the two largest zones favored distance vision; and the intermediate size was likely the best option for those patients who have the same needs for both distance and near.¹⁶

Decentered optics in multifocal lenses are becoming more popular. Lenses tend to decenter on the eye, so decentering the optics in the lens can help to center them over the pupil and the line of sight, improving visual response compared to multifocals lenses that have centered optics.¹⁷ This is particularly important with scleral multifocals, which tend to decenter slightly inferior (because of their mass) and temporal (because the nasal sclera is more elevated). Newer designs are being introduced with the optics decentered superior-nasal. To determine the amount of decentration needed, it has been recommended to perform topography both without a lens and over the lens and then to use subtractive tangential maps to find the centration point of the multifocal optics.¹⁸

IRREGULAR CORNEAS

Every year, the CLS GP Prescribing Survey includes a question regarding contact lens prescribing preferences for irregular corneas. As Table 3 shows, scleral lenses once again predominate as the go-to option (i.e., 52% of respondents fit at least half of their irregular cornea patients into scleral lenses). This is a large increase from last year, when 39% of respondents fit ≥ 50% of their irregular cornea patients into sclerals. Small-diameter GP lenses, however, decreased from 26% to 18% in this category. Intralimbal lenses remained constant, while hybrid, custom soft, and piggyback options all decreased.

With regard to keratoconus, it is not surprising that GP lenses represent the best option to improve visual acuity after corneal cross-linking for corneal ectasia.¹⁹ That said, it is important to have all of these lenses in your irregular cornea fitting toolbox; this was the conclusion of a recent study evaluating corneal GP, scleral GP, and soft lenses in the correction of keratoconus.²⁰ It was reported that the visual performance was similar between corneal and scleral GP designs; and, although soft lenses did not result in the same quality of vision, they did improve visual performance over spectacles and should be considered as a viable alternative in some cases.

LENS CARE

As mentioned previously, the introduction of contact lens disinfection standards was a major development in 2020. This information is also available in a condensed form as an in-office laminated card, which is available from the GP Lens Institute at www.gpli.info/ordering .

The introduction of a scleral lens filling solution that is in unit-dose form, buffered, and that includes five natural electrolytes for improved ocular compatibility was well received by ECPs. In addition, a popular brand of preservative-free saline received approval from the FDA for rinsing and filling of scleral lenses for up to 14 days after opening. The CLS GP Prescribing Survey asked readers which type of solution was their go-to filling solution for scleral lenses (Table 4). With the recent introduction of several FDA-approved solutions, it is evident that FDA-approved sodium chloride-based solutions are becoming very popular and were preferred by 43% of respondents. Sodium chloride inhalation solutions were preferred by 33%, nonpreserved tears and lubricants by 13%, and preserved wetting/conditioning solutions were preferred by 12%. This last finding is particularly disconcerting because of the potential toxicity that can result from preserved solution being in contact with the eye during the entire duration of scleral lens wear.

One new development in lens care that is eagerly awaited is the introduction of a solution that renews the surface coating treatment for GP lenses. This solution is designed to rebuild the original layer of the polyethylene glycol (PEG)-based coating to its full thickness and to restore the benefits of the coating to that of a freshly treated lens. This solution will be a prescription product that a patient can use at home. At this time, it is under review by the FDA but is expected to be approved in late 2020.

THE FUTURE

The next 12 to 36 months should be exciting ones in the GP industry. The greatest growth is most likely to be in the scleral arena, as the use of profilometry will continue to grow, resulting in greater success in matching lens design to sclera but also in allowing growth in empirical fitting of scleral lenses. In addition, wavefront-guided lenses will become more readily available and should increase in popularity as a result of the improved visual outcome. A 200-Dk lens material is now available. These improvements and others in scleral lens design and materials will likely result in increased use, increased success, and decreased need for corneal transplants in diseased eyes.

The current explosion of myopia management with contact lenses—including increased soft multifocal, OOK, and pharmaceuticals use—will only increase as new lenses are introduced to the market and the results of clinical research continue to indicate which method or combination of methods is optimal for a given young person. Regarding OOK, I would like to think that Dr. Jeff Walline (see the sidebar on p. 34) was being a prophet when he commented that “Perhaps an orthokeratology contact lens will be created that further enhances myopia control, either through drug release, enhanced optics, or both.”

Presbyopia management innovations will include an increasing use of decentered optics to optimize vision by aligning the optics of the contact lens with the visual axis. Of course, in the not-too-distant future, we should have available an accommodative custom soft lens. A new empirically fit hybrid lens in both a single-vision and a center-near multifocal option that utilizes a proprietary design with extended depth of focus will also enter the market in the near future. CLS

Acknowledgements: Roxanne Achong-Coan, OD; Tiffany Andrzejewski, OD; Richard Baker, OD; Melissa Barnett, OD; Mile Brujic, OD; Steve Byrnes, OD; Karen Carrasquillo, OD; Gloria Chiu, OD; Brian Chou, OD; Robert L. Davis, OD; Daniel Deligio, OD; Greg DeNaeyer, OD; Tim Edrington, OD, MS; Barry Eiden, OD; Robert Ensley, OD; Jennifer Fogt, OD; Wendy Ford; Melanie Frogozo, OD; Dan Fuller, OD; Bob Grohe, OD; Susan Gromacki, OD, MS; Jonathan Jacobson (Acuity Polymers); Jason Jedlicka, OD; Jeff Johnson, OD (Robert W. Baird); Matt Kauffman, OD; Beth Kinoshita, OD; Elise Kramer, OD; Jamie Kuhn, OD; Karen Lee, OD; Mike Lipson, OD; Derek Louie, OD; Ken Maller, OD; Marsha Malooley, OD; Brittney Mazza, OD; Vic McCray, MD (Tangible Science); Rob McGregor (Contamac); Langis Michaud, OD, MSc; Heidi Miller, OD; Clarke Newman, OD; Craig Norman; Roxanna Potter, OD; Tom Quinn OD, MS; Phyllis Rakow; Renee Reeder, OD; Susan Resnick, OD; Pam Satjawatcharaphong, OD; Louise Sclafani, OD (SynergEyes); Joe Shovlin, OD; Brian Silverman, OD; Jeff Sonsino, OD; Long Tran, OD; Maria Walker, OD, MS; Jeff Walline, OD, PhD; Bruce Williams, OD; and Stephanie Woo, OD.

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