Different Approaches to RGP Fitting for Presbyopia

Fitting GP lenses on keratoconus patients who have presbyopia is always challenging. The images above show two different approaches to fitting GPs in presbyopic patients. The left image is a mild, irregular cornea with stage I keratoconus, and the right image is an advanced keratoconus case.

History

Figure 1 is from a 59-year-old female patient. She was fitted with aspheric concentric GP multifocals with far vision at the center and progressive add around the distance zone.¹

Figure 2 shows a 58-year-old patient who has a stabilized, stage II keratoconus. In this case, he was fitted with a monovision,² dominant eye (OD) for distance and nondominant (OS) for near vision with +1.75D. add.

Contact Lens Fitting

Fitting multifocal needs more detail, the most important is to obtain a good lens centralization to function properly. Measure pupil size in low-light and daylight conditions as pupil size variations will determine mild modifications to the multifocal design.

Fitting monovision specialty GPs for keratoconus requires a good balance between the dominant eye distance vision and the nondominant eye for near vision. If the combination is correct, the patient should present good neuro-visual adaptation.

Conclusion

The results in both cases were optimal. The mild keratoconus patient fitted with GP multifocals achieved 20/15 and J1 in both eyes. The advanced keratoconus patient achieved 20/25⁺³ in his dominant eye (OD) and J1 OS—excellent adaptation. Both techniques are valuable options depending on the patient condition.

References

1. Davis RL, Cogswell B. An “Essential” Approach to Multifocal Fitting. Contact Lens Spectrum. 2005 Nov;20. Available at clspectrum.com/issues/2005/november-2005/an-essential-approach-to-multifocal-fitting . Accessed May 15, 2023.
2. Evans BJW. Monovision From the Contact Lens Practitioner’s Perspective. CRST Global Europe Edition, 2009 Oct. Available at crstodayeurope.com/articles/2009-oct/1009_11-php . Accessed May 15, 2023.

Mr. Bastos is the director and clinical instructor of specialty contact lenses at the Instituto de Olhos Dr. Saul Bastos (IOSB) and is the director and specialty lens consultant of Ultralentes, a small laboratory specializing in GP and scleral lens designs in Porto Alegre, RS, Brazil.