BackgroundThis retrospective cross-sectional study aims to analyse the keratoconus (KC) stage distribution at different ages within the Homburg Keratoconus Center (HKC).Methods1917 corneae (1000 patients) were allocated to decades of age, classified according to Belin’s ABCD KC grading system and the stage distribution was analysed.Results73 per cent (n=728) of the patients were males, 27% (n=272) were females. The highest KC prevalence occurred between 21 and 30 years (n=585 corneae, 294 patients). Regarding anterior (A) and posterior (B) curvature, the frequency of A was significantly higher than B in all age groups for stage 0, 1 and 2 (A0>B0; A1>B1; A2>B2; p<0.03, Wilcoxon matched-pairs test). There was no significant difference between the number of A3 and B3, but significantly more corneae were classified as B4 than A4 in all age groups (p<0.02). The most frequent A|B combinations were A4|B4 (n=451), A0|B0 (n=311), A2|B4 (n=242), A2|B2 (n=189) and A1|B2 (n=154). Concerning thinnest pachymetry (C), most corneae in all age groups were classified as C0>C1>C2>C3>C4 (p<0.04, Wilcoxon matched-pairs test). For the best distance visual acuity (D), a significantly higher number of corneae were classified as D1 compared to D0 (p<0.008; D1>D0>D2>D3>D4).ConclusionThe stage distributions in all age groups were similar. Early KC rather becomes manifest in the posterior than the anterior corneal curvature whereas advanced stages of posterior corneal curvature coincide with early and advanced stages of anterior corneal curvature. Thus, this study emphasises the necessity of posterior corneal surface assessment in KC as enabled by the ABCD grading system.

ZusammenfassungDer Keratokonus (KK) ist eine progrediente kegelförmige Hornhautvorwölbung, die eine parazentrale Verdünnung an der Kegelspitze verursacht und typischerweise beidseitig asymmetrisch auftritt. Nach einer sorgfältigen Anamnese und Einstufung des Schweregrades steht heute eine gezielte stadiengerechte Therapie zur Verfügung. Ist der Brillenvisus nicht mehr ausreichend, werden von einem Spezialisten formstabile sauerstoffdurchlässige Kontaktlinsen (KL) angepasst. Bei Progression und für den Patienten im Alltag nutzbarem Visus empfiehlt sich das Riboflavin-UVA-Crosslinking (CXL), bei herabgesetztem Visus und klarer zentraler Hornhaut sind bei KL-Intoleranz intrastromale Ringsegmente (ICRS) indiziert. Ist das Stadium weiter fortgeschritten, empfiehlt sich die tiefe anteriore lamelläre (DALK) oder perforierende Keratoplastik (PKP). Bei einem akuten Keratokonus ist die PKP kontraindiziert, allerdings verkürzen tiefstromale Nähte zur Readaptation des Descemet-Risses mit Gasfüllung der Vorderkammer den Verlauf erheblich. Fast keine andere Augenerkrankung ist heutzutage einer frühen apparativen Diagnose und stadiengerechten Therapie so gut zugänglich wie der KK.

Purpose: To point out the biomechanical changes of the topographically and tomographically normal partner eye (NPE) in patients with very asymmetrical corneal ectasia. Setting: Department of Ophthalmology, Saarland University Medical Center in Homburg/Saar, Germany. Design: Retrospective study. Methods: The topographical and tomographical results of the NPE were assessed using the Pentacam HR and the biomechanical corneal properties using the Ocular Response Analyzer (keratoconus match index [KMI], corneal hysteresis [CH], and corneal resistance factor [CRF]) and the Corvis ST (topographic biomechanical index [TBI] and Corvis biomechanical index) and compared those results with a normal control group (CG). Results: The clinical records of 26 patients recruited from the Homburg Keratoconus Center diagnosed with a very asymmetrical corneal ectasia were reviewed. The NPE (8.5 ± 1.5 mm Hg) showed a significantly more pathological CH (P < .001) compared with the CG. The CRF was also significantly more pathological (P = .04) for the NPE (8.3 ± 1.5 mm Hg) compared with the CG. The NPE (0.62 ± 0.32) showed a nonsignificant (P = .08) more pathological KMI compared with the CG. Nineteen (73.1%) of 26 NPE had a KMI less than 0.72 and were considered pathological. Compared with the CG, the TBI of the NPE (0.19 ± 0.25) did not differ significantly overall (P = .57). However, 5 (19.2%) of 26 eyes had a TBI more than 0.29 and were considered pathological. Conclusions: Topographically and tomographically NPEs in very asymmetrical corneal ectasia frequently showed biomechanical changes. This should be considered before planning any type of refractive corneal surgery in such patients.

Purpose: To determine the changes of corneal thickness and curvature of human corneal grafts in organ culture medium II, containing dextran T500 6%, before keratoplasty. Methods:We examined the tomography of 24 corneas from our eye bank transferred from medium I into medium II. Images were repeated hourly during 24 hours using an anterior segment optical coherence tomography. The central corneal thickness (CCT) was measured with the manual measurement tool of the anterior segment optical coherence tomography. The radii of curvature (anterior flat and steep and posterior flat and steep) were measured with a MATLAB self-programmed software for "sterile donor tomography."Results: The mean CCT (6SD) at baseline (T0) was 727 6