EACH YEAR IN JANUARY, an international cohort of contact lens practitioners, industry partners, academics, and other experts meet in Las Vegas to attend the Global Specialty Lens Symposium (GSLS). Some of these individuals—typically those participating in, or who are intrigued by, research involving scleral lenses (SLs)—come a day early to attend the International Forum for Scleral Lens Research (IFSLR). This four-hour meeting focuses on sharing and discussing research related to SLs.
In January 2024, the seventh annual IFSLR was held. Here, we will summarize the presentations and highlight discussions of work being conducted around the world in SL research.
SESSION I: OCULAR PHYSIOLOGY AND SCLERAL LENSES
The first session of IFSLR began with an assessment of SL fitting data from 1,300 patients seen by Charles Vervaet, BSc, from the Netherlands. Focusing on the implementation of an oval landing zone to combat midday fogging (MDF) and conjunctival prolapse, he shared how the asymmetry of the cornea contributes to these SL complications.
Vervaet measured the horizontal and vertical corneal diameters in his patient cohort (n = 1,300) and found that horizontal corneal diameter (12.14mm) was greater than vertical (11.32mm) (Figure 1A). These dimensions generally agree with the established literature, although his horizontal dimensions were approximately 0.5mm greater than the often referenced 11.7mm.1,2
Vervaet asserted that limbal clearance is related to both MDF and conjunctival prolapse. He also noted that excess clearance, which is inherently greater in the superior and inferior quadrants in a spherical (symmetrical) SL due to the shorter vertical dimension, can increase suction and create an easy passage for debris and loose tissue to come into the fluid reservoir (FR), particularly in the inferior quadrant (Figure 1B). He noted specifically that conjunctival prolapse more commonly occurs inferiorly (agreeing with the literature),3-6 which often has the greatest amount of limbal clearance. By creating oval optical zones (Figure 1C), the amount of clearance in these superior and inferior areas can be reduced and subsequently reduce conjunctival prolapse and MDF.
Next, Maria Walker, OD, PhD, discussed work she’s been performing to evaluate the composition of the FR in keratoconus (KC) patients wearing SLs (n = 38), comparing them to non-KC SL wearers (n = 13). Previous work has shown that the FR contains cytokines (e.g., IL-4, IL-8, MMP-7, 9, 10), lipids, and cells, in varying concentrations in MDF and other conditions,7-8 and the work presented looked specifically in KC patients.
She found that there were potential elevations of IL-18, VEGF, and IFN-γ in the KC cohort compared to those without KC (unpublished data), which could be indicative of a different response of the KC to a SL compared to other SL wearing populations. Interestingly, there were not differences between IL-6 between KC and non-KC samples, which is unexpected since IL-6 is typically elevated in KC tears.9-12 More work is needed to specifically classify the inflammation in the FR of KC patients during SL wear.
In the final presentation of the first session, Bita Asghari, OD, presented a recent publication on the use of scleral lenses for long-term ocular surface support in patients who have a permanent keratoprosthesis (KPro).13 She initiated her presentation by outlining the indications for a KPro (i.e., severe ocular surface or corneal diseases who have failed with penetrating keratoplasty) and discussed the many risks and considerations for long-term care of these patients. She reported that KPro has classically been managed with continuous bandage soft contact lens (BSCL) wear and use of an antibiotic and steroid to control for infection and inflammation, respectively.
In the presentation of her recent paper, Dr. Asghari reported on four eyes of four patients who underwent a KPro implantation due to complex dry eye disease-related complications. Remarkably, scleral contact lens wear improved vision in all patients (Table 1). Although there were complications such an nonhealing defects, she reported that all four patients in the series did stabilize and were able to successfully wear the SLs. This presentation provided evidence that using a SL in KPro patients can be accomplished safely and effectively.
SESSION II: OPTICAL AND DESIGN ADVANCES WITH SL
The second session focused on advances in SL optical and design characteristics. Jason Jedlicka, OD, initiated this session with a similar theme as Vervaet in the first session, talking about the asymmetry of the ocular surface shape. He explained that when a spherical SL lands on a toric or irregular ocular surface, the door is opened for physiological challenges such as vascular blanching, conjunctival prolapse, MDF, and lens edge standoff.
He further emphasized that as the peripheral cornea transitions to limbus and finally to conjunctiva and sclera, there typically will be significant shifts in the surface topography. Contemporary instrumentation allows practitioners and laboratories to address these inevitable topographical changes. Toric and quadrant-specific lenses are likely to reduce SL complications and will, for these reasons, be more frequently prescribed.
The IFSLR meetings frequently discuss the advances in optical design of SLs, particularly lenses with higher-order aberration-correcting optics. In the second presentation in session II, John Gelles, OD, reported his experience in a private practice setting with wavefront-guided SLs prescribed for a variety of conditions. Most patients’ visual acuity (VA) improved by one to two lines and higher-order root mean square (HORMS) aberrations were reduced by 50% to 55%. Patient acceptance of wavefront-correcting optics was 90% to 95%.14
SLs can also be prescribed for low-vision patients. Swati Kumar, OD, the third presenter in this session, described how a SL, in conjunction with a spectacle frame, may be designed to form a telescope system useful for patients in need of low-vision management. The design described followed the Galilean principle with a high-minus power in the SL and a lenticulated high-plus power lens mounted in a spectacle frame. This optical system delivers approximately 2-times to 2.5-times magnification.
In addition, SLs may become very versatile prosthetic devices. This was demonstrated by Chandrashekhar Chawan, PhD, who reported on good outcomes with hand-painted SLs (Figure 2) to improve the cosmetic appearance for patients who have aniridia, iris coloboma, and pupillary trauma and to achieve a desired cosmetic change of iris color. The coloring of the SL is accomplished by infusing the dye pigment into the lens material so that it will become a permanent part of the lens. However, it was pointed out during discussion that painted SL can reduce oxygen permeability by as much as 30%. There have been no recent reports of lens Dk in painted SLs in the peer-reviewed literature. Given the unclear understanding of lens Dk in these custom SLs, it may be prudent to select a lens material with a higher Dk value for SL patients in need of an opaque tint.
SESSION III: SL LONGEVITY—HYGIENE AND LENS REPLACEMENT
The third session of IFSLR 2024 focused on important clinical questions associated with special populations fitted with SLs. Gloria Chiu, OD, summarized the results of her recent study on recommended and actual SL replacement intervals.15 She and her colleagues retrospectively reviewed the lens order history of 251 SL patients (445 eyes) who had reordered a SL for, at minimum, one eye between Jan. 1, 2019, and Dec. 12, 2019. The mean (SD) replacement interval for SLs in this population was 23.9 (14.3) months (range five to 2,617 days).
William Miller, OD, PhD, next discussed the importance of meticulous cleaning and disinfection for SLs. Studies have shown that virtually all contact lens wearers exhibit at least one behavior that could increase their risk of a contact lens-related complication.16-17 Given that many SL patients have preexisting ocular disease, it is important to make sure that they understand the importance of following provider recommendations for lens care and maintenance.
Dr. Miller suggested that using non-preserved saline packaged in single-dose units, incorporating surfactant cleaning, storing the lens appropriately overnight in a multipurpose solution or hydrogen peroxide, and cleaning and replacing contact lens cases and plungers are essential steps in any SL patient’s daily regimen. He also acknowledged that additional studies are needed to define the optimal care regimen for SL patients.
In the final presentation of the session and the day, Janna Pham, OD, described an interesting case in which a patient experienced an acute hypersensitivy reaction following lens cleaning (Figure 3). In this case, a patient who had heavy deposits and discoloration of his lens presented for an annual examination. After lens care treatment, a slight remaining hue of discoloration can still be observed on the lenses. The patient developed a hypersensitivity reaction that included chemical dilation of his pupils and conjunctival hyperemia, suspected to be caused by residual cleaner on the lenses that may have attached to the lens deposits and leached into the patient’s eyes after the treatment.
This case highlighted the importance of developing a personalized cleaning and disinfection plan based upon each patient’s ocular condition, lens deposit profile, and reaction to various cleaning products and procedures, along with the need to be aware of less common care products such as ultrasonic cleaners. Ultimately, it was agreed by the panel and the experts in the audience that in these cases, it would be prudent to include other cleaning regimens (e.g., sonication, polishing) to ensure removal of any deposits that could retain strong cleaners and potentially cause an ocular reaction. Of note, the importance and utility of strong cleaners and disinfection systems was emphasized by many experts, who simply recommend that in these extreme cases of severe deposits it may be sensible to include other interventions to remove stubborn deposits.
CONCLUSIONS
The seventh annual IFSLR highlighted the emerging advances in lens designs using improved instrumentation and recognizing that the peripheral anatomy may lead to better control of complications such as MDF and conjunctival prolapse. Furthermore, application of wavefront and other advanced optical corrections in SL are in the process of improving vision and satisfaction with the devices. Lastly, the importance of SL replacement and cleaning regimens cannot be ignored and is in need of future studies and evolution. The eighth annual IFSLR is scheduled live on Jan. 15 prior to the commencement of GSLS 2025 in Las Vegas.
Acknowledgments: The authors would like to acknowledge the researchers and clinicians who presented at the seventh annual IFSLR and provided content for this article. Support for the seventh IFSLR was provided by Bausch Health, CooperVision, Contamac, Valley Contax, and Visionary Optics. We appreciate the educational support from our media partners, Conexiant, and the Global Specialty Lens Symposium, as well as our educational partner, the Scleral Lens Education Society.
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