Objectives: To compare the clinical performance of the Clearkone hybrid contact lens for the treatment of keratoconus against the habitual contact lens of the patients.
Methods: A total of 33 eyes from 18 patients were fitted with the Clearkone. High- and low-contrast visual acuity (HCVA and LCVA), central corneal thickness (CCT), and contrast sensitivity acuity (CSF) were recorded with habitual lenses (prestudy visit) and after 1 week, 15 days, and 1 month of wear of prescribed Clearkone. Subjective vision and comfort were rated using visual analogue scales (VAS).
Results: Three patients discontinued the study, one because of diffuse corneal staining after 1 day of use and the other two because of extreme discomfort. The rest of the patients completed the 1-month study. High contrast visual acuity and LCVA (logMAR) improved significantly from 0.16 ± 0.12 and 0.44 ± 0.22, respectively, with the patient's habitual contact lenses to −0.006 ± 0.058 and 0.23 ± 0.13 after 1 day wearing Clearkone, remaining significant during all follow-up visits (P<0.001; repeated measures analysis of variance [RM-ANOVA]). There were no statistically significant differences in the mean CCT. The improvement of CSF was statistically significant with hybrid contact lenses prescribed compared with the patient's habitual contact lenses (P<0.001; RM-ANOVA test). Improvement in VAS score, with prescribed Clearkone, was statistically significant for comfort (P=0.043; RM-ANOVA test), but not for the subjective vision (P=0.759; RM-ANOVA test).
Conclusions: Clearkone provides an improvement in visual acuity, contrast sensitivity, and subjective comfort in patients with keratoconus when compared with other contact lens options. However, clinicians must get specific training to fit the lens and be aware of potential adverse events.
Department of Optics II (Optometry and Vision) (G.C., J.C.), Faculty of Optic and Optometry, Universidad Complutense de Madrid, Madrid, Spain; Clinical & Experimental Optometry Research Lab (J.M.G.-M., D.L.-F.), Center of Physics (Optometry), School of Sciences, University of Minho, Braga, Portugal; and Laboratorios Lenticon SA (G.C., L.B.), Madrid, Spain.
Address correspondence to Gonzalo Carracedo, Faculty of Optic and Optometry, Department Optics II (Optometry and Vision), C/Arcos del Jalon 118 28032, Madrid, Spain; e-mail: firstname.lastname@example.org
The authors have no financial interest on the materials and instruments used in this study. G. Carracedo is a part-time employee and L. Batres is a full-time employee of Laboratorios Lenticon SA, distributor of Clearkone in Spain and Portugal. None of the authors have received funding to conduct this study.
Accepted July 26, 2013