Clinical Scorecard: Midday Fogging: What It Causes and What Causes It

At a Glance

Key Highlights

• Midday fogging is characterized by fluid reservoir debris causing visual blur in scleral lens wearers.
• Front-surface nonwetting and diffuse haze are significantly associated with subjective fogging symptoms.
• No specific lens design or care product has been linked to midday fogging; ocular surface inflammation may contribute.

Guideline-Based Recommendations

Diagnosis

• Use slit lamp biomicroscopy to evaluate fluid reservoir depth, limbal clearance, edge lift or impingement, conjunctival prolapse, front-surface wetting, mucous strands, particulate debris, and diffuse fluid reservoir haze.
• Assess patient-reported symptoms of fogging during scleral lens wear.

Management

• Address front-surface nonwetting and reduce diffuse haze to mitigate fogging symptoms.
• Consider ocular surface inflammation as a contributing factor if redness or irritation is present.

Monitoring & Follow-up

• Regular slit lamp examinations to monitor fluid reservoir characteristics and front-surface wetting status.
• Monitor patient-reported fogging symptoms and ocular surface signs during follow-up visits.

Risks

• Visual quality reduction due to fluid reservoir debris accumulation.
• Potential ocular surface inflammation associated with elevated inflammatory mediators in the post-lens fluid reservoir.

Patient & Prescribing Data

Scleral lens wearers experiencing subjective fogging symptoms

Fogging is not linked to specific lens designs or care products; management should focus on improving lens surface wetting and addressing ocular surface inflammation.

Clinical Best Practices

• Perform comprehensive slit lamp biomicroscopy focusing on fluid reservoir characteristics and lens surface wetting.
• Incorporate patient symptom reports to guide clinical assessment and management.
• Evaluate and manage ocular surface inflammation when present to reduce fogging.
• Educate patients about the potential causes of fogging and the importance of follow-up care.

References

• Barnett M et al. CLEAR – scleral lenses. Cont Lens Anterior Eye. 2021
• Fogt JS et al. Slit lamp findings in scleral lens wearers with and without subjective fogging. Eye Contact Lens. 2025
• Postnikoff CK et al. Identification of leukocytes associated with midday fogging. Invest Ophthalmol Vis Sci. 2019
• Schornack MM et al. Factors associated with patient-reported midday fogging. Cont Lens Anterior Eye. 2020