Improved Interchangeability with Different Corneal Specular Microscopes for Quantitative Endothelial Cell Analysis.

INTRODUCTION: During our clinical practice and research, we encountered an interchangeability problem when using the SP-2000P and SP-3000P TopCon corneal specular microscopes (CSMs) (TopCon Medical Systems, Tokyo, Japan) regarding the endothelial cell count (ECC). We describe a method to improve interchangeability between these CSMs. METHODS: Five consecutive good-quality endothelial cell photographs were obtained in 22 eyes of 11 subjects. An ECC comparison between the two CSMs was performed after (I) gauging and calibration by the manufacturer, (II) adjustment of the magnification, (III) correction after external horizontal and vertical calibration. RESULTS: There was a statistically significant difference between the ECC of the SP-2000P and SP-3000P at the start. The SP-2000P counted an average of 500 cells/mm2 more than the SP-3000P (p=0.00). After correction for magnification and determining a correction factor based on external calibration, the difference between the ECC of the SP-2000P and the SP-3000P was then found to be 0.4 cells/mm2 and was not statistically significant (p=0.98). DISCUSSION: We propose a method for improving interchangeability, which involves checking magnification settings, re-checking magnification calibration with external calibration devices, and then calculating correction factors. This method can be applied to various specular or confocal microscopes and their associated endothelial cell analysis software packages to be able to keep performing precise endothelial cell counts and to enable comparison of ECCs when a CSM needs to be replaced or when results from different microscopes need to be compared.

Straylight As The Result Of Refractive Correction.

PURPOSE: To investigate the effect of refractive correction on straylight. PATIENTS AND METHODS: Straylight values were measured with the C-Quant (Oculus Optikgeräte, GmbH, Wetzlar, Germany) in 1) near-emmetropic eyes (n=30) with various negative powered refractive lenses and in 2) myopic eyes (n=30) corrected with prescribed eyeglasses and contact lenses. The straylight measurements in each group were compared in the different conditions. RESULTS: In the near-emmetropic group, a significant effect (p<0.001) of each added negative diopter was found to increase straylight values with 0.006 log-units. In the second group, no significant correlation with type of correcting lens was found on straylight values. CONCLUSION: Refractive correction with high minus power (contact) lenses result in subtle increase of straylight values. These changes are relatively small and do not lead to visual disability in a clinical setting.

Clinical characteristics and long-term visual outcome of severe phenotypes of chronic central serous chorioretinopathy.

PURPOSE: The aim of this study was to investigate disease onset and disease progression in patients with severe chronic central serous chorioretinopathy (cCSC). PATIENTS AND METHODS: The medical records of 143 cCSC patients (199 eyes) were reviewed. All cases had visual complaints for >6 months and showed signs of a severe disease phenotype on optical coherence tomography (OCT) and fluorescein angiography (FA). Clinical presentation at onset was evaluated, together with disease progression on multimodal imaging and final treatment outcome. RESULTS: Twenty-eight cases (14%) had a documented history of an acute episode of CSC, whereas 145 cases (73%) showed pre-existing features of chronicity already at first presentation. The first clinical presentation could not be evaluated in 13% of cases. Best-corrected visual acuity (BCVA) was 70 ± 18 Early Treatment of Diabetic Retinopathy Study (ETDRS) letters at onset and 70 ± 22 ETDRS letters at final visit (p = 0.770). Among all studied cases, 173 eyes (87%) were treated, which resulted in complete resolution of subretinal fluid (SRF) in 76% of eyes at final visit. In eyes with fluorescein angiographic follow-up, the area of diffuse atrophic retinal pigment epithelium (RPE) abnormalities (diffuse atrophic RPE alterations [DARA]) had increased significantly in 43 eyes (68%) at final visit. CONCLUSION: CSC encompasses a clinical spectrum that includes a range of severe phenotypes, in which retinal abnormalities tend to be progressive. Nevertheless, the long-term visual acuity may remain fairly stable with treatment. Few patients with severe chronic CSC have a history of acute CSC, which could indicate that there may be pathogenetic differences between these 2 CSC variants.

High levels of Hdmx promote cell growth in a subset of uveal melanomas.

The p53 tumor suppressor pathway is inactivated in cancer either via direct mutation or via deregulation of upstream regulators or downstream effectors. P53 mutations are rare in uveal melanoma. Here we investigated the role of the p53 inhibitor Hdmx in uveal melanoma. We found Hdmx over-expression in a subset of uveal melanoma cell lines and fresh-frozen tumor samples. Hdmx depletion resulted in cell-line dependent growth inhibition, apparently correlating with differential Hdm2 levels. Surprisingly, p53 knockdown hardly rescued cell cycle arrest and apoptosis induction upon Hdmx knockdown, whereas it effectively prevented growth suppression induced by the potent p53 activator Nutlin-3. In addition, two compounds inhibiting Hdmx function or expression, SAH-p53-8 and XI-011, also elicited a growth inhibitory effect in a partly p53-independent manner. These findings suggest a novel, growth-promoting function of Hdmx that does not rely on its ability to inhibit p53. We provide evidence for a contribution of p27 protein induction to the observed p53-independent G1 arrest in response to Hdmx knockdown. In conclusion, our study establishes the importance of Hdmx as an oncogene in a subset of uveal melanomas and widens the spectrum of its function beyond p53 inhibition.