Visual Acuity and Refractive Error Improvement in Keratoconic Patients: A Low-Income Context Management Perspective

• Main Authors: Kibet Yego W, Moodley VR
• Format: Article
• Language: English
• Published: Dove Medical Press 2020-08-01
• Series: Clinical Optometry
• Subjects: keratoconus; cornea; visual outcomes; rigid gas permeable; scleral lenses; myopia
• Online Access: https://www.dovepress.com/visual-acuity-and-refractive-error-improvement-in-keratoconic-patients-peer-reviewed-article-OPTO

Walter Kibet Yego,1 Vanessa Raquel Moodley2 1Department of Optometry and Vision Sciences, Masinde Muliro University of Science and Technology, Kakamega, Kenya; 2Department of Optometry, University of KwaZulu-Natal, Durban, South AfricaCorrespondence: Walter Kibet YegoDepartment of Optometry and Vision Sciences, Masinde Muliro University of Science and Technology, Kakamega, KenyaTel [phone]Email [e-mail]: Visual acuity (VA) and refractive error (RE) remain important parameters in the management of keratoconic (KC) patients. Despite rapid amelioration in capacity of diagnostic equipment, these remain inaccessible to the majority of practitioners in low-income countries. Notwithstanding limitations, practitioners are expected to utilize existing resources to satisfactorily manage their increasing numbers of keratoconic patients.Purpose: To determine the changes in visual acuity and refractive errors with diagnostic and management options available in low-income contexts.Methods: A descriptive, retrospective chart analysis of medical records dating back 5 years was employed in this study. Records of patients prescribed with corneal rigid gas permeable (RGP) and scleral lenses were analyzed. Data on age, gender, stage of keratoconus, pre-, and post-visual acuities and refractive errors, mode of correction and lens parameters were evaluated.Results: A total of 124 medical records were analyzed. Males comprised 58.9% and females 41.1% of the total sample, with a mean age 20.86 ± 9.50 years. The mean unaided VA in logMAR notation was 1.0± 0.19, while corrected VA was 0.18± 0.17. There was a significant improvement (p= 0.001) in VA with corneal RGP contact lenses (mean 0.19± 0.17) as compared to unaided VA (mean 1.29± 0.20). Scleral lens VA also improved from a median of 1.06 to − 0.01 logMAR; p= 0.001. The mean RE before RGP contact lens fitting was − 9.43± 2.37 diopters (D) which improved to − 0.41± 0.78D. RE reduced significantly (p= 0.001) after fitting with both corneal RGP lenses (from a mean of − 9.80± 4.46D to − 0.45± 0.80D) and scleral lenses (from a median of − 8.00D to − 0.02D).Conclusion: Significantly improved visual acuity and refractive error status were achieved with all KC patients. Despite the diagnostic equipment and contact lenses design limitations, practitioners in low-income contexts can fit the relatively more affordable corneal RGP lenses to positively impact the daily living experiences of their KC patients.Keywords: keratoconus, cornea, visual outcomes, rigid gas permeable, scleral lenses, myopia