Safety of intravitreal quinupristin/dalfopristin in an animal model.

AIM: To determine whether different intravitreal doses of quinupristin/dalfopristin lead to electroretinographic or histological changes in the rabbit retina over one month period after injection. METHODS: Eighteen New Zealand white rabbits were divided into three treatment groups (groups 1 to 3) and different intravitreal doses of quinupristin/dalfopristin were tested in each group. The right eye was injected with the drug and the left eye received intravitreal injection of 5% dextrose water and served as control eye. The doses delivered to each group were 0.1 mg/0.1 mL, 1 mg/0.1 mL and 10 mg/0.1 mL. Simultaneous, bilateral, dark-adapted electroretinography and clinical images of both eyes were obtained in all groups before injection (baseline) and after 7, 14, 21 and 28d, followed by enucleation for histological examination. RESULTS: Subjects in the group 1 showed no signs of toxicity in the electroretinogram when compared with groups 2 and 3 (Kruskall-Wallis test, P=0.000). By day 7, no electrical response to light stimuli was recorded in the treated eyes in groups 2 and 3, consistent with severe damage due to retinal toxicity. Light microscopy revealed no significant histopathological changes in the group 1, while rabbits in groups 2 and 3 had signs of granulomatous inflammation in most cases. CONCLUSION: Intravitreal 0.1 mg/0.1 mL doses of quinupristin/dalfopristin do not lead to electroretinographic or histological signs of retinal toxicity compared with 1 mg/0.1 mL and 10 mg/0.1 mL in this rabbit model.

Comparison of iridocorneal angle in infants with retinopathy of prematurity and healthy infants using spectral domain optical coherence tomography.

PURPOSE: To compare measurements and morphologic characteristics of the iridocorneal angle in preterm infants with retinopathy of prematurity (ROP) and healthy infants using spectral domain optical coherence tomography (SD-OCT). METHODS: In this observational, case-control study, the eyes of children with ROP and healthy controls under 1 year old were imaged using SD-OCT without sedation to capture the iridocorneal angle. The ROP staging was made by a pediatric retinal specialist. The following measurements were analyzed with custom software: angle opening distance (AOD500) at 500 µm; angle opening in degrees (AOG); and angle recess area (ARA750). RESULTS: A total of 27 eyes of 14 children with ROP and 21 of 13 children without ROP were included. The mean gestational age of children in the ROP group was 30 weeks; of the controls, 35 weeks. The mean birth weight in the ROP group was 1,545 g; in the non-ROP group 2,100 g. Mean age at the time of the study was 18.1 (ROP group) vs 25.7 weeks (non-ROP). In the ROP group AOD500 was 477 µm (95% CI, 358-597 µm), AOG was 37.3° (95% CI, 30.4°-44.3°), and ARA750 was 231 mm(2) (CI 95%, 171-291 mm(2)). The same parameters on the non-ROP group were 400 µm (CI 95% 333-468 µm), 34.7° (CI 95% 30.4°-39°), and 203 mm(2) (95% CI, 171-236 mm(2)). The iris showed a more convex pattern on eyes with ROP (56% vs 23%). CONCLUSIONS: In this study cohort, children with ROP showed higher AOD500, AOG, and ARA750, perhaps because of different patterns of physiological development in children with ROP.

Optic disc and macula detection in fundus images by means of template matching.

Various methods for detecting optic disc and macula in fundus images have been developed. Our aim is to propose a fairly easy method for detecting both features jointly. This is achieved by first correcting in homogenous luminosity using a polynomial approximation of the background of the images. Secondly, the use of the cross-correlation in the frequency domain between the images and a steerable template which contains both structures. The 38 photographs used in this work belong to a local database of patients suffering diabetic retinopathy along its four severity stages. Our results showed 100% optic disc centers located within the OD area and 90% macula centers located within the MC area.