Purpose-To describe baseline and longitudinal findings of the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study.Methods-The CLEK Study is an eight-year, multi-center, natural history study of 1,209 patients with keratoconus who were examined annually for eight years. Its goals are to prospectively characterize changes in vision, corneal curvature, corneal status, and vision-specific quality of life.Results-CLEK Study subjects had a mean age at baseline of 39.3 +/− 10.9 years. At study entry, 65% of the patients wore rigid contact lenses, and 14% reported a family history of the disease. Subjects exhibited a seven-year decrease in high-(2.03 letters) and low-(4.06 letters) contrast, best-corrected visual acuity, with 19% demonstrating decreases of 10 or more letters in high-contrast, best-corrected acuity and 31% of subjects demonstrating decreases of 10 or more letters in low-contrast, best-corrected acuity in at least one eye. Subjects exhibited an average eight-year increase in corneal curvature of 1.60 D in the flat corneal meridian, with 24% demonstrating increases of 3.00 D or more. The eight-year incidence of corneal scarring was 20%, with younger age, corneal staining, steeper baseline corneal curvature, contact lens wear, and poorer low-contrast visual acuity predictive of corneal scarring. Data from the National Eye Institute Visual Function Questionnaire suggest that the effect of keratoconus on vision-specific quality of life is disproportionate to its low prevalence and clinical severity.Conclusion-Although we report measures of disease severity and visual function across the CLEK sample, clinicians can begin to envisage the course of keratoconus in individual patients by determining whether factors predictive of disease progression are present in those patients.

Overnight orthokeratology is an effective means of temporarily reducing myopia. The possible mechanism of corneal remodeling through central corneal thinning is discussed.

A simple and reliable grading system for keratoconus was developed that can be largely automated. Such a grading scheme could be useful in genetic studies for a complex trait such as keratoconus requiring a quantitative measure of disease presence and severity.

CRT results in reduced low-contrast BCVA as a result of increased higher-order aberrations. Higher-order aberrations appear to be relatively stable after CRT. Spherical aberration appears to drive additional low-contrast BCVA losses as pupil size increases.

The preliminary results of the LOOK study indicate that improvement in unaided visual acuity can be attained for at least 6 h after lens removal. The short-term safety and efficacy of the procedure appear to be favorable; however, future studies are needed to determine the long-term outcomes of treatment.

No abstract

Aim To investigate glutathione and antioxidant status changes in erythrocytes from febrile children receiving repeated supratherapeutic paracetamol doses. Methods Fifty-one children aged 2 months to 10 years participated in the study. Three groups were studied: group 1 ( n = 24) included afebrile children who did not receive paracetamol; and groups 2 ( n = 13) and 3 ( n = 14) included children who had fever above 38.5 ∞ C for more than 72 h. Patients in group 2 received paracetamol at a dose of 50 ± 15 (30-75) mg kg -1 day -1 and those in group 3 received paracetamol above the recommended therapeutic dose, ie 107 ± 28 (80-180) mg kg -1 day -1 . A blood sample was taken for the measurement of liver transaminases, gammaglutamil transferase (GGT), reduced glutathione (GSH), glutathione reductase (GR), glutathione peroxidase (GPX), glutathione S-transferase (GST), superoxide dismutase (SOD) and antioxidant status. Results Aspartate aminotransferase activity in group 3 was higher than in the other groups ( P = 0.027). GSH, SOD and antioxidant status were significantly lower in group 3 compared with groups 1 and 2 (mean differences: for GSH 3.41 m mol gHb -1 , 95% confidence interval (CI) 2.10-4.72, and 2.15 m mol gHb -1 , 95% CI 0.65-3.65, respectively; for SOD 856 U min -1 gHb -1 , 95% CI 397-1316, and 556 U min -1 gHb -1 , 95% CI 30-1082, respectively; and for antioxidant status 0.83 mmol l -1 plasma, 95% CI 0.30-1.36, and 0.63 mmol l -1 plasma, 95% CI 0.02-1.24, respectively). GR activity was significantly lower in groups 3 and 2 in comparison with group 1 (mean differences 3.44 U min -1 gHb -1 , 95% CI 0.63-6.25, and 5.64 U min -1 gHb -1 , 95% CI 2.90-8.38, respectively). Using multiple regression analysis, paracetamol dose was found to be the only independent variable affecting GR, GST and SOD activities ( P = 0.007, 0.003 and 0.008, respectively). Conclusions In febrile children, treatment with repeated supratherapeutic doses of paracetamol is associated with reduced antioxidant status and erythrocyte glutathione concentrations. These significant changes may indicate an increased risk for hepatotoxicity and liver damage.

Both low- and moderate-astigmatic eyes showed improvements in acuity with toric contact lenses. Lens brand had a measurable effect on acuity for toric contact lenses. Further investigation of aberrations induced by contact lens design is warranted to explain the observed differences in visual performance.