Scleral lens wear: Measuring inflammation in the fluid reservoir

Potential pro-inflammatory impact of scleral lens midday fogging on human corneal epithelial cells: An in vitro study

PURPOSE

Midday fogging (MDF) occurs when particulate material accumulates in the fluid reservoir (FR) beneath scleral lenses (SL), and its impact on epithelial cells is unknown. This study examines the in vitro pro-inflammatory effect of the FR on human corneal epithelial cells in varying degrees of MDF.

METHODS

Normal SL neophytes were recruited to wear SL 8 h daily for 4 days. Following 8 h on days 1 and 4, optical coherence tomography (OCT) images were acquired for MDF quantification using ImageJ, and the FR was collected. FR samples from the same eye were later pooled, diluted 2-fold and applied on human telomerase-immortalized corneal epithelial (hTCEpi) cells cultured on Terasaki microwell plates. Tumor necrosis factor (TNF)-α and culture media were used as positive and negative controls, respectively. After a 30-minute treatment, the nuclear factor-kappa B (NF-κB) pathway was measured by NF-κB-p65 immunofluorescence and images were analyzed with ImageJ. Pearson's correlation was conducted to determine the association between median nuclear fluorescence and MDF.

RESULTS

Fourteen FR samples with a mean volume of 22 ± 16 µl were tested. Mean MDF severity following 8 h of SL wear was 25 ± 17 units (range 7 - 64). The median nuclear fluorescence (NF-κB-p65 translocation) in cultured hTCEpi cells ranged from 31.43 to 45.16 while the negative and positive controls were 44.71 ± 1.72 and 108.77 ± 68.38, respectively. Although a potential positive trend between MDF and median nuclear fluorescence was observed, Pearson's correlation analysis revealed no significant association (r = +0.48, P = 0.09).

CONCLUSIONS

The results suggest that the FR can trigger NF-κB-p65 translocation in hTCEpi cells, which may be associated with MDF severity. This study introduces the use of Terasaki microwell plates for immunofluorescence studies of the FR. The technique is simple, minimizes sample usage, and does not require expensive instrumentation.

Ocular Surface Homeostasis After Scleral Lens Usage

OBJECTIVES

The aim of this prospective study is to examine the effects of 5 hours of well-fitted, mini-scleral contact lens (mini-SL) wear on the tear film cytokine expression in healthy eyes.

METHODS

Twenty-three healthy participants were included in the study. One eye of each participant was selected at random, and a mini-SL measuring 16.5 mm in diameter was fitted by an experienced contact lens specialist. The contact lens remained in place for 5 hours. Precorneal tear fluid was collected using capillary tubes at three different time points: baseline before SL insertion (T0), after 5 hours of SL wear (T1), and 3 hours after SL removal (T2). The concentration of 40 inflammatory cytokines at the three different time points was determined using multiplex bead assay.

RESULTS

Mini-scleral lens wear did not result in significant changes in the cytokine-to-protein ratio after 5 hours of wear on a healthy eye.

CONCLUSIONS

Although a well-fitted mini-SL reduces the rate at which the precorneal tear film is refreshed, 5 hours of lens wear did not appear to significantly affect the tears cytokine-to-protein ratio, suggesting that scleral lenses have minimal impact on corneal cytokine expression.

Nonpolar Lipids Contribute to Midday Fogging During Scleral Lens Wear

Purpose

To determine correlations between lipids in the fluid reservoir (FR) and the severity of midday fogging (MDF) in scleral lens (SL) wear.

Methods

SL neophytes were recruited to wear custom SL for 4 days, examined after 8 hours on days 1 and 4. Lens vault and MDF were quantified from anterior segment optical coherence tomography (AS-OCT), and the FR was collected and analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Relative abundance of lipids was compared to MDF scores using nonparametric correlation testing (Spearman rank). Ocular surface and SL fitting characteristics (lens vault, fitting curves) were likewise compared to MDF.

Results

Thirteen participants (26 eyes, 69% female, 28 ± 9 years old) were included in this study. MDF severity after 8 hours of SL wear was 33 ± 29 units on day 1 and 28 ± 24 units on day 4 (r = .94; P < 0.01). Twelve samples were analyzed using LC-MS/MS, and a total of 170 distinct lipid species were detected. The lipid classes with greatest correlation to MDF were the wax esters (r = .73, P = 0.01), cholesteryl esters (r = .59; P = 0.049), and triacylglycerols (r = .64, P = 0.03). Polar lipids were observed abundantly in all samples. None of the measured ocular surface or fitting outcomes were correlated to MDF.

Conclusions

Nonpolar lipids were the greatest contributors to MDF among these normal participants. Polar lipids may be due to cellular debris, although they do not appear contributory to MDF.

Midday Fogging of Scleral Contact Lenses: Current Perspectives

Midday fogging is a common problem in scleral lens wear, as particles accumulate in the tear reservoir between the posterior surface of the lens and the front of the ocular surface during wear. As particulate waste collects, symptoms of blurred vision and discomfort arise, typically leading patients to remove their lenses for cleaning, refilling with fresh solution, and reinsertion into the eye. The appearance of the particulate can vary, likely due to different causes for midday fogging. Studies which attempted to identify the particulate have given some insight into some of the causes, but larger studies are needed to identify this debris. Research on lens solutions used for filling the lens reservoir and of various aspects of scleral lens fits have also begun to culminate in the concept that midday fogging may ultimately be related to inflammation. Since scleral lens wearers can have varied and multiple sources of inflammation, strategies in minimizing midday fogging can differ between patients.

Microbiological Evaluation of Opened Saline Bottles for Scleral Lens Use and Hygiene Habits of Scleral Lens Patients

SIGNIFICANCE

Scleral lenses have become a widely used treatment option for patients with irregular corneas and ocular surface disease. Successful wear entails use of a nonpreserved saline solution to fill the lens before application on the eye.

PURPOSE

The purposes of this study were to evaluate solution from opened bottles of multidose preservative-free saline for microbiological growth and to better understand study participant hygiene habits while handling these bottles for scleral lens wear.

METHODS

Eligible study participants in this single-center prospective study were patients who routinely used multidose preservative-free saline solution for scleral lens rinsing and filling. Study participants completed a 12-question survey regarding their scleral lens hygiene habits and donated their opened multidose preservative-free saline bottle (PuriLens Plus; The Lifestyle Company, Inc., Freehold, NJ), which was processed for bacterial and fungal cultures.

RESULTS

Thirty-five participants (19 males, 16 females) with ages ranging from 6 to 81 years (mean, 47.9 years) were included. Indications for scleral lens wear included those with irregular corneas and ocular surface disease. The overall rate of microbial contamination among saline samples was 62.9% (n = 22). Twenty-one different microorganisms were identified. The survey responses did not differ significantly (P > .05) for any of the questions with regard to likelihood of positive culture. There were no significant age or sex differences between participants with positive or negative culture results. No significant differences were found between isolation of specific microorganisms and any of the survey responses.

CONCLUSIONS

This study suggests that off-label multidose preservative-free saline commonly used to rinse and fill scleral lenses before application on the eye may become contaminated with microorganisms once the bottle has been opened. Eye care practitioners and scleral lens patients should be aware of these potential contaminations and prioritize lens, hand, and environmental hygiene to minimize the risk of ocular complications.

Anatomical and physiological considerations in scleral lens wear: Eyelids and tear film

Scleral lenses can affect a range of anterior segment structures including the eyelids and the tears. The eyelids, consisting of the outer skin layer, the middle tarsal plate, and the posterior palpebral conjunctiva, provide physical protection and house the meibomian glands and cilia which have important and unique functions. Tears consist of a mix of aqueous, mucus, and lipidomic components that serve vital functions of lubricity, protection, and nourishment to the ocular surface. Both the eyelids and the tear film interact directly with scleral lenses on the eye and can affect but also be impacted by scleral lens wear. The purpose of this paper is to review the anatomy and physiology of the eyelids and tear film, discuss the effects and impacts of the scleral lenses on these structures, and identify areas that require further research.

The impact of hybrid contact lenses on keratoconus progression after accelerated transepithelial corneal cross-linking

PURPOSE

To investigate the effect of hybrid contact lenses (HCLs) on keratoconus (KCN) progression after accelerated transepithelial cross-linking (A-TE CXL).

METHODS

Thirty-five eyes of 26 patients who preferred Ultrahealth HCLs for an optical correction after A-TE CXL formed the study group, and 45 eyes of 34 patients who preferred spectacle correction were age- and sex-matched to form the control group. Corrected distance visual acuity (CDVA), maximum keratometry, mean keratometry, apical posterior keratometry, cylindrical power, minimum corneal thickness, keratoconus vertex indices and curvature asymmetry indices obtained by Scheimpflug corneal topography were compared before, 6 and 12 months after the procedure. Anterior segment optic coherence tomography (AS-OCT) was performed to measure the apical corneal clearance of HCL-wearing patients.

RESULTS

The median pre-CXL CDVA value of the patients in the HCL group was logMAR 0.30 (0.20-1.0), and it was logMAR 0.30 (0.10-1.0) in the spectacle-corrected group. There was a significant increase in CDVA 6 and 12 months after CXL procedure in both groups (p < 0.001, 0.003, respectively). The median front curve asymmetry index (FCAsym) significantly improved after A-TE CXL in the HCL group. The pre-CXL and 12th-month topographic comparisons of the spectacle-corrected group revealed no significant difference. In addition, no significant difference was observed between topographic alterations of two groups (p > 0.05).

CONCLUSION

The CDVA significantly improved, and KCN progression was halted in patients wearing HCL 12 months after A-TE CXL. Besides, FCAsym indices can be considered for follow-up of the HCL-wearing patients as an assistive parameter to AS-OCT measurements.