Midday fogging describes fluid reservoir debris, which is a common finding in scleral lens wearers.¹ Midday fogging may decrease visual quality and is used to illustrate visual blur.^2-4 A prospective, observational study of 48 habitual scleral lens wearers examined whether fit characteristics and biomicroscopic findings contribute to symptoms of fogging. The scleral lens wearers came from 5 clinical sites, and they wore scleral lenses either monocularly or binocularly. Participants reported whether they experienced scleral lens fogging. Slit lamp biomicroscopy was used to evaluate the depth of the fluid reservoir (FR), absence or presence of limbal clearance, edge lift or impingement, conjunctival prolapse, and nonwetting of the front surface. Absence or presence of mucous strands, fine particulate debris, and diffuse FR haze were also reported.

Backward elimination binomial logistic regression using a single eye of each scleral lens wearer matched the findings of eyes with and without subjective fogging. The goal is to identify the model that still effectively explains the relationship with the binary outcome with the fewest possible parameters.

Fogging was reported by 28 of 48 participants (58%). Statistical analysis revealed no substantial differences in scleral lens fitting characteristics between eyes with and without fogging. However, front-surface nonwetting and diffuse haze were significantly more common in scleral lens wearers experiencing fogging. In this patient-reported study, front-surface nonwetting and diffuse haze evaluated using slit lamp biomicroscopy were associated with scleral lens fogging.

Another study found that midday fogging was not linked to a specific lens design or care product.⁴ However, if inflammatory mediators are elevated in the post-lens FR, the associated redness or irritation may indicate that ocular surface inflammation plays a contributing role.⁴

References

1. Barnett M, Courey C, Fadel D, et al. CLEAR – scleral lenses. Cont Lens Anterior Eye. 2021 Apr;44(2):270-288. doi: 10.1016/j.clae.2021.02.001

2. Fogt JS, Schornack M, Nau C, Harthan JS, Nau A, Shorter E. Slit lamp findings in scleral lens wearers with and without subjective fogging.Eye Contact Lens. 2025 Jul 2. [Online ahead of print] doi: 10.1097/ICL.0000000000001204

3. 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;60(1):226-233. doi: 10.1167/iovs.18-24664

4. 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;43(6):602-608. doi: 10.1016/j.clae.2020.03.005

Melissa Barnett, OD, FAAO, FSLS, has received remuneration from ABB, Abbvie, Alcon, Azura, Bausch + Lomb, BCLA, Bruder, Cloudbreak Pharma, CooperVision, Dompé, Epion, JJVC Vistakon, Lentechs, Ocusoft, Orasis, ScienceBased Health, STAPLE Program, Tarsus, and Théa Pharma.

 This editorial content was supported via unrestricted sponsorship.