Do Patients With Keratoconus Have Minimal Disease Knowledge?

PURPOSE: To assess whether Swiss adult citizens diagnosed with keratoconus have the minimal knowledge that a corneal specialist would expect they should have. METHODS: Experts defined the "minimal keratoconus knowledge" (MKK) with respect to definition, risk factors, symptoms, and possible treatment options of keratoconus. A survey was performed in 167 patients with keratoconus [mean age 38.8 years (SD 13.9), 77.7% male] in 5 specialized institutions. Of each participant, salient clinical characteristics, highest educational level, paramedical background, and specific health experience with keratoconus in the social surrounding were obtained. We calculated the proportion of MKK and examined whether patients with higher education and greater disease experience would perform better than those from other groups in multivariate analyses. RESULTS: No single citizen reached 100% MKK. The mean MKK was 35.2%, and the range was 0% to 76.2%. Participants with a university degree had only a moderately higher MKK [+8.7% (95% confidence interval: 4.4-13.0); P < 0.001]. Per age decile, the MKK declined by 3.1% (95% confidence interval: 1.2-4.9), P = 0.002. Disease duration, severity of keratoconus in Kmax values, and history of surgical treatment did not significantly increase MKK. Surprisingly, MKK was also lower in patients with a paramedical background [-6.3% (-14.1 to 1.4); P = 0.107]. CONCLUSIONS: This sample of Swiss patients with keratoconus did not know more than a third of the MKK. We found a little difference within various subgroups. There is a substantial mismatch between caregivers' expectations of patients' knowledge and patients' active knowledge regarding their condition. This may lead to an inefficient care delivery and misunderstandings.

An analysis of anterior scleral shape and its role in the design and fitting of scleral contact lenses.

PURPOSE: The purpose of this study was to evaluate the shape of the anterior sclera by measuring the sagittal height and corneoscleral transition angles in the four cardinal and four oblique segments of the eye. MATERIALS AND METHODS: In this study, 78 normal eyes of 39 subjects were evaluated. The sagittal height, corneoscleral angle and scleral angle were measured at three chord lengths (10.0mm, 12.8mm and 15.0mm) in all eight segments of the anterior eye using optical coherence tomography (Zeiss Visante AS-OCT). Scleral toricity was calculated for each eye, defined as the greatest sagittal height difference found between two perpendicular meridians. RESULTS: At a 12.8mm chord length, the shape of the anterior eye was found to be nearly rotationally symmetric, and at a chord of 15.0mm the shape became more asymmetric. The average sagittal heights of the eight segments at a 12.8mm chord ranged from 2890µm to 2940µm; at a 15.0mm chord they ranged from 3680µm to 3790µm. The average scleral angles at a 15.0mm chord ranged from 35.17° to 38.82°. Significant differences between opposing segments were found in the sagittal height and scleral angle measurements at a chord of 15.0mm (sagittal height p≤0.0021; scleral angle p≤0.0105). The nasal measurements revealed flatter scleral angles and concave corneoscleral transitions, whereas temporal scleral angles were steeper, with tangential or convex corneoscleral transitions. CONCLUSION: These findings are important to consider when designing and fitting contact lenses that rest beyond the boundaries of the limbus, such as scleral lenses.