Purpose: The vision in keratoconus is most often best corrected with rigid gas permeable lenses, and patients with keratoconus often rely on contact lenses as their primary means to clear vision. In cases of lost contact lenses or anterior segment disease that requires the cessation of contact lens wear, these patients are often left without a viable means of vision correction. The purpose of this study is to determine if “back-up” spectacles could provide adequate vision for keratoconus patients in times of contact lens cessation.
Methods: Eleven participants were prescribed spectacles and completed two examinations in this study. High and low contrast Bailey-Lovie visual acuity was measured with the participants’ habitual contact lenses and manifest refraction was performed at examination one. High and low contrast Bailey-Lovie visual acuity was measured with the spectacles prescribed in the study and a repeat manifest refraction was performed at examination two. Slit lamp biomicroscopy, keratometry, and automated topography using the Atlas topographer was also performed at both examinations. Participants wore their contact lenses from morning to 6:00 p.m. and their spectacles from 6:00 p.m. to bedtime on Day 1 and Days 3-6 of the study. Spectacles only were worn on Day 2 of the study. Participants completed a patient log during the study to record their experiences with glasses wear.
Results: High contrast visual acuity for manifest refraction between examination one and examination two dropped an average of 1.8 ± 4.1 letters both eyes together, dropped by an average of 1.0 ± 4.6 letters for the “worse eyes,” and dropped by an average of 2.4 ± 5.7 letters for the “better eyes.” The average number of hours that the glasses were worn was 6.35 ± 3.80 hours for Days 1 and Days 3-6 of the study and 13.94 ± 4.44 hours for Day 2 of the study. Participants rated that vision in the glasses was slightly worse than vision in the contact lenses on average. The most common subjective visual response reported by the participants was Positive Adaptation.
Conclusions: If proper expectations regarding visual performance are put into place by the eye care practitioner prior to spectacle use, keratoconus patients may be successful with “back-up” spectacles in circumstances that require the cessation of contact lenses.