Clinical Scorecard: Rethinking Tear Exchange in Sclerals

At a Glance

Key Highlights

• Scleral lenses exhibit minimal tear exchange compared to soft and corneal rigid lenses, contributing to complications like post-lens debris and corneal hypoxic stress.
• Peripheral channel modifications in scleral lenses significantly increase tear exchange, especially in the corneal periphery, compared to toric landing zones or notches.
• Enhanced tear exchange via channel designs may reduce complications and guide future scleral lens customization.

Guideline-Based Recommendations

Diagnosis

• Assess corneal health and suitability for scleral lens wear in adults with normal corneas.

Management

• Consider scleral lens modifications such as peripheral channels to enhance tear exchange and reduce complications like midday fogging and hypoxic stress.
• Use toric landing zones to reduce lens rotation and maintain fit stability.

Monitoring & Follow-up

• Monitor for post-lens fluid reservoir debris and midday fogging during extended scleral lens wear.
• Evaluate tear exchange dynamics using fluorescein profilometry or equivalent methods when available.

Risks

• Extended scleral lens wear with minimal tear exchange may increase risk of corneal hypoxic stress and fluid reservoir debris accumulation.

Patient & Prescribing Data

Nine healthy adults with normal corneas, mean age 34 years

Peripheral channel modifications in scleral lenses increased tear ingress and fluorescein intensity, indicating improved tear exchange compared to toric and notch designs.

Clinical Best Practices

• Fit scleral lenses with a 150 µm toric landing zone to reduce rotation and optimize fit.
• Incorporate peripheral channel modifications to enhance tear exchange and potentially reduce complications.
• Use noninvasive profilometry and fluorescein to quantitatively assess tear exchange during lens wear.
• Reapply sodium fluorescein after lens settling to evaluate tear ingress and exchange dynamics.

References

• Iqbal et al. Quantifying tear exchange during rigid contact lens wear using corneoscleral profilometry
• Kok et al. Fluorophotometric assessment of tear turnover under rigid contact lenses
• Paugh et al. Silicone hydrogel and rigid gas-permeable scleral lens tear exchange
• Walker et al. Complications and fitting challenges associated with scleral contact lenses: A review
• Iqbal et al. Peripheral scleral lens modifications and tear exchange
• Alexander et al. The effect of landing zone toricity on scleral lens fitting characteristics and optics
• Iqbal et al. Scleral lens landing zone toricity and tear exchange