This article was originally published in a sponsored newsletter.

Fluid reservoir debris, otherwise referred to as midday fogging, is a frequent finding in scleral lens wearers.¹ Midday fogging has been reported in 26% to 46% of patients and may reduce the quality of vision.^2,3 The precise etiology and composition of this particulate matter is unclear. However, reservoir debris has been associated with lipids,⁴ leukocytes,¹ and external tear film debris.⁶ The primary symptom of foggy or blurry vision may appear instantaneously after lens application or after wearing scleral lenses for several hours.^5,3

The presence of midday fogging is differentiated from front-surface lens fogging with biomicroscopy, optical coherence tomography (OCT), or Scheimpflug imaging.¹

A prospective study of 48 existing scleral lens wearers investigated whether midday fogging was present and whether scleral lens removal and reapplication were necessary each day. A validated dry eye assessment questionnaire, the Ocular Surface Disease Index (OSDI), was completed.

Documentation was done on lens characteristics (diameter, material, and coatings), as well as the filling and storage options. Backward elimination of regression terms was used to assess the lens and solution properties in individuals who did and did not experience fogging. OSDI scores were compared using Mann-Whitney analysis.

In total, solutions and lens properties accounted for 27.7% of midday fogging-related variance. No individual factor had a substantial effect on midday fogging. The median (interquartile range) OSDI score for individuals with fogging was significantly higher (37 [35]) than for those without fogging (10 [15]). These scores correspond to severe dry eye and normal eye conditions, respectively.

In this study, scleral lens (SL) wearers experiencing midday fogging demonstrated symptoms similar to individuals who have severe dry eye. While lens and solution characteristics may contribute to midday fogging, altering a single factor is unlikely to eliminate the issue.

Midday fogging is currently managed by periodic scleral lens removal and reapplication. Additionally, changing the fitting modifications (e.g., improving landing zone alignment or reducing reservoir thickness^2,6 or material,⁵ adjusting the care regimen to a hydrogen peroxide-based system or altering the filling solutions including a more viscous solution,⁷ application of a lens surface treatment⁸ and treating underlying ocular surface disease including allergies and dry eye disease⁹) may help to mitigate midday fogging symptoms.

Reference(s):

1. Barnett M, Courey C, Fadel D, et al. CLEAR - Scleral lenses. Cont Lens Anterior Eye. 2021 Apr;44:270-288.
2. Postnikoff CK, Pucker AD, Laurent J, Huisingh C, McGwin G, Nichols JJ. Identification of leukocytes associated with midday fogging in the post-lens tear film of scleral contact lens wearers. Invest Ophthalmol Vis Sci. 2019 Jan 2;60:226-233.
3. Schornack MM, Fogt J, Harthan J, et al. Factors associated with patient-reported midday fogging in established scleral lens wearers. Cont Lens Anterior Eye. 2020 Dec;43:602-608.
4. Walker M, Morrison S, Caroline P, et al. Laboratory Analysis of Scleral Lens Tear Reservoir Clouding. Poster Presented at The 2014 Global Specialty Lens Symposium, Las Vegas. 2014.
5. Walker MK, Bergmanson JP, Miller WL, Marsack JD, Johnson LA. Complications and fitting challenges associated with scleral contact lenses: a review. Cont Lens Anterior Eye. 2016 Apr;39:88-96.
6. Skidmore KV, Walker MK, Marsack JD, Bergmanson JPG, Miller WM. A measure of tear inflow in habitual scleral lens wearers with and without midday fogging. Cont Lens Anterior Eye. 2019 Feb;42:36-42.
7. Fogt JS, Karres M, Barr JT. Changes in Symptoms of Midday Fogging with a Novel Scleral Contact Lens Filling Solution. Optom Vis Sci. 2020 Sep;97:690-696.
8. Mickles CV, Harthan JS, Barnett M. Assessment of a Novel Lens Surface Treatment for Scleral Lens Wearers With Dry Eye. Eye Contact Lens. 2021 May 1;47:308-313.
9. Fadel D. Scleral Lens issues and complications related to a non-optimal fitting relationship between the Lens and ocular surface. Eye Contact Lens. 2019 May;45:152-163.

Melissa Barnett, OD, FAAO, FSLS is the director of optometry at the University of California, Davis. She has received remuneration from ABB, Acculens, Abbvie, Azura, Bausch + Lomb, BCLA, Bruder, Bruno Vision Care, CooperVision, Dompé, Epion, JJVC Vistakon, Lentechs, Ocusoft, Orasis, RVL Pharmaceuticals, Sight Sciences, Science Based Health, STAPLE Program, Sun Pharma, Taursus, and Visus.