Clinical Scorecard: Prescribing for Astigmatism: Using Front Toric Optics Early

At a Glance

Key Highlights

• Scleral lenses effectively neutralize corneal surface astigmatism and irregularities, with residual astigmatism impacting visual outcomes.
• Front-surface toric optics are indicated when residual astigmatism is ≥0.75 DC and provide significant visual acuity improvement.
• Early incorporation of front toric optics, facilitated by scleral profilometry and diagnostic lenses, enhances patient satisfaction and reduces lens orders.

Guideline-Based Recommendations

Diagnosis

• Perform spherocylindrical over-refraction to identify residual astigmatism after lens settling.
• Use scleral profilometry to select appropriate toric back-surface lenses and assess lens rotation stability.
• Employ diagnostic lenses to detect residual ocular astigmatism, especially in irregular corneas.

Management

• Incorporate front-surface toricity into the initial lens order if residual astigmatism ≥0.75 DC with subjective visual improvement.
• Correct lens flexure by ensuring precise haptic alignment with scleral toricity or increasing lens thickness.
• Address lens decentration by improving lens fit to avoid induced aberrations and astigmatism.
• Consider wavefront-guided optics for patients with residual higher-order aberrations affecting visual satisfaction.

Monitoring & Follow-up

• Note lens rotation after adequate settling time to ensure stability before adding front toric optics.
• Monitor patient subjective visual improvement comparing spherocylindrical versus spherical equivalent over-refraction.

Risks

• Lens flexure and decentration can induce aberrations and residual astigmatism if not properly managed.
• Uncorrected residual astigmatism may reduce visual acuity and patient satisfaction.

Patient & Prescribing Data

Scleral lens wearers with corneal astigmatism, including irregular corneas and those dissatisfied with conventional correction

Early use of front-surface toric optics after confirming stable lens fit and residual astigmatism improves visual outcomes and patient motivation for lens handling.

Clinical Best Practices

• Use scleral profilometry to guide early selection of toric back-surface lenses.
• Perform spherocylindrical over-refraction after lens settling to detect residual astigmatism.
• Incorporate front toric optics early when indicated to maximize visual acuity and patient satisfaction.
• Correct lens flexure and decentration proactively to avoid induced aberrations.
• Consider wavefront-guided optics for patients with persistent higher-order aberrations despite conventional correction.

References

• Hastings GD et al., 2019 - Comparison of wavefront-guided and best conventional scleral lenses
• Nguyen LC et al., 2020 - Case report on '20/20 unhappy' scleral lens patients