Objective:

Review evidence on whether ocular and contact lens sagittal height can inform soft contact lens fitting beyond central corneal curvature measurements.

Approach:

• Lens design measurements: A 2021 study measured contact lens sagittal height (CL-SAG) in 44 commercially available spherical and toric soft lenses.
• Fit assessment: A 2025 study fitted 30 subjects with eight daily disposable lenses and assessed the relationship between ocular sagittal height (OC-SAG), CL-SAG, and fit using imaging and two clinicians’ subjective assessments.
• Adverse events: A 2025 study compared OC-SAG in 25 patients with contact lens-related corneal infiltrative events or microbial keratitis against a control population of more than 18,000 contact lens wearers.

Key Findings:

• Lenses with the same labeled base curve showed substantial CL-SAG variation across manufacturers; differences were also substantial between some designs from the same manufacturer.
• Switching from a spherical to a toric lens of the same type and manufacturer could change CL-SAG by as much as 500 µm.
• In the 30-subject fitting study, a CL-SAG 120–280 µm deeper than OC-SAG was associated with satisfactory fit.
• Patients with corneal infiltrative events or microbial keratitis had flatter OC-SAG than the control population.

Interpretation:

The article describes ocular sagittal height as a potential fitting consideration because keratometry covers only the central 3 mm of the cornea and does not capture diameter-dependent sagittal depth. The authors of the adverse-event study hypothesized that shallow OC-SAG may contribute to excessively steep fits with one-size-fits-most lenses.

Limitations:

• The fitting study included 30 subjects and eight daily disposable lens designs.
• The adverse-event study included 25 affected participants; the reported association does not establish that shallow OC-SAG causes adverse events.
• The article does not provide detailed study methods or results beyond the summarized measurements and findings.

Conclusion:

The reviewed research suggests that base curve labels alone may not reflect meaningful differences in soft lens sagittal height. The article presents OC-SAG and CL-SAG comparison as a possible approach to fitting, while noting that trial fitting remains in use.

Sources:

• Young et al. (2010), Corneal topography and soft contact lens fit
• van der Worp et al. (2021), Variation in sag values in daily disposable, reusable and toric soft contact lenses
• Cruz-Crespo et al. (2025), Changing the paradigm of soft contact lens fitting: A sagittal height-based approach
• Waghmare and Jeria (2022), A review of contact lens-related risk factors and complications
• Ozkan et al. (2010), Risk factors for corneal inflammatory and mechanical events with extended wear silicone hydrogel contact lenses
• Andrew et al. (2025), The relationship between soft contact lens adverse events and corneal sagittal depth