Genetic variants in the FOXO1 and ZNF469 genes are associated with keratoconus in Sweden: a case-control study.

BACKGROUND: Keratoconus (KC) is characterized by pathological thinning and bulging of the cornea that may lead to visual impairment. The etiology of sporadic KC remains enigmatic despite intensive research in recent decades. The purpose of this study was to examine the relationship between previously highlighted genetic variants associated with KC and sporadic KC in a Swedish cohort. METHODS: A total of 176 patients (age 16-70 years) with sporadic KC diagnosed by Scheimpflug-topography (Pentacam) were included. The control group (n = 418; age 70 years) was a subsample originating from the Gothenburg H70 Birth Cohort Studies of ageing. Extraction of DNA from blood samples was performed according to standard procedures, and genotyping was performed using competitive allele specific PCR (KASP) technology. A total of 11 single nucleotide polymorphisms (SNPs) were selected for analysis. RESULTS: Statistically significant associations (p = 0.005) were found between the SNPs rs2721051 and rs9938149 and sporadic KC. These results replicate earlier research that found associations between genetic variants in the FOXO1 and BANP-ZNF469 genes and sporadic KC in other populations. CONCLUSION: Genetic variations in the FOXO1 and BANP-ZNF469 genes may be involved in the pathogenesis of sporadic KC.

Repeated Same-Day Versus Single Tomography Measurements of Keratoconic Eyes for Analysis of Disease Progression.

PURPOSE: Corneal tomography is used to assess progression of keratoconus and to direct clinical decisions regarding corneal cross-linking. The purpose of this study was to analyze the variability of repeated Scheimpflug-tomography (Pentacam Classic; Oculus, Wetzlar, Germany) measurements of keratoconic eyes in a clinical setting and to assess the validity of such measurements as a clinical decision-making tool. METHODS: Eighty keratoconic eyes of 45 patients (age range 16-32 years) were examined at baseline and after follow-up periods of 3 to 6 months using 3 consecutive tomography measurements at each visit. Minimum corneal thickness and anterior sagittal curvature map parameters were studied [simulated keratometry (K) astigmatism (SimKast); maximum simulated K-reading (SimKmax); average SimK (SimKave); maximum K-readings on the 3-mm (Kmax3) and 5-mm (Kmax5) rings; and maximum K-reading (Kmax)]. RESULTS: When comparing the first measurements at the first and second visits, respectively, 9% to 20% of eyes were classified as progressive depending on which parameter was chosen. Using the average of 3 consecutive measurements at each visit, 5% to 19% of eyes were classified as progressive. An increase in the SD of 3 consecutive measurements of SimKast (SD_SimKast) at the first visit of 1 diopter makes true progression of keratoconus 3.6 times more likely (odds ratio = 3.6; 95% confidence interval: 0.846-16.027; area under the curve = 0.70). CONCLUSIONS: The approach used to analyze progression in keratoconus, that is, single versus repeated measurements, may confer a great impact on the decision to perform corneal cross-linking treatment or not.

Accommodation and the relationship to subjective symptoms with near work for young school children.

The aim of this work was to study the relation between subjective symptoms at near and ocular accommodation in terms of the amplitude of accommodation and the relative accommodation. A secondary aim was to discuss the diagnosis of accommodative insufficiency. The chosen cohort was examined on two occasions with 1.8 years in between. The first examination included 72 children, 43 boys (mean age 8.1 years, ranging from 5.8 to 9.8) and 29 girls (mean age 8.3 years, ranging from 6.2 to 10.0). The second examination included 59 of these children, 34 boys (mean age 9.9 years, ranging from 7.8 to 11.7) and 25 girls (mean age 10.1 ranging from 8.0 to 11.8). Subjective symptoms at near work (headache, asthenopia, floating text, facility problems) were recorded and the amplitude and the relative accommodation, both positive and negative, were measured. The result from the questionnaire showed that at the first examination more than one-third of the children (34.7%) reported at least one subjective symptom when doing near work and 42.4% at the second examination. No symptoms were found among children younger than 7.5 years, but for children between 7.5 and 10 years old at the first examination, the prevalence of at least one symptom was 47.2%. At the second examination, symptoms were reported also for the youngest children, i.e. from the age of 8 years. The discrimination ability for the amplitude of accommodation, both monocular and binocular, was significant. In the first examination the difference between the mean for the two groups (i.e. with and without at least one symptom) was around 2.00 D monocular and 3.00 D binocular. Corresponding figures from the second examination was a difference between the mean for the two groups of around 3.50 D monocular and nearly 4.00 D binocular. We suggest that accommodation measurements should be performed more routinely and regularly, maybe as screening, especially in children over 8 years of age.

The amplitude of accommodation in 6-10-year-old children - not as good as expected!

The aim of this study was to measure the amplitude of accommodation for junior level school children and to compare it with age-expected values. A junior level school in Göteborg, Sweden, was randomly chosen and the amplitude of accommodation among 76 children aged 6-10 years was examined using Donders' push-up method. The results showed lower amplitude than expected in a large group of children. Results also showed lower amplitude than previously reported for this age group, especially under monocular conditions, which revealed an average dioptric difference from the expected value of -3.60 dioptres (D) right eye (mean 12.40 D, median 12.00 D, S.D. 3.7 D) and -3.50 D left eye (mean 12.50 D, median 12.70 D, S.D. 3.8 D) (p < 0.001 for both eyes). Consequently, we conclude that it cannot be assumed that the amplitude of accommodation is in the expected amplitude range for all children of these ages.