A Telemedical Approach to the Scre e n i n g of Diabetic Retinopathy: Digital Fundus P h o t o g r a p h y O R I G I N A L A R T I C L E O B J E C T I V E -The importance of screening for diabetic retinopathy has been established, but the best method for screening has not yet been determined. We re p o rt on a trial of assessment of digital photographs by telemedicine compared with standard retinal photographs of the same fields and clinical examination by ophthalmologists. RESEARCH DESIGN AND METHODS-A total of 129 diabetic inpatients were s c reened for diabetic retinopathy by slit-lamp biomicroscopy perf o rmed by an ophthalmologist and by two-field 50° non-stereo digital fundus photographs assessed by six screening centers that received the images by electronic mail. Conventional 35-mm transparencies of the same fields as the digital photographs were assessed by a retinal specialist and served as the re fe rence method for detection of diabetic re t i n o p a t h y. Slit-lamp biomicroscopy was the re f e re n c e method for the detection of macular edema. R E S U LT S -The prevalence of any form of diabetic retinopathy was 30% (n = 35); of sightt h reatening retinopathy including macular edema, the prevalence was 6% (n = 7). The assessment of digital images by the six screening centers resulted in a median sensitivity of 85% and a median specificity of 90% for the detection of moderate nonproliferative or sight-thre a t e ning diabetic re t i n o p a t h y. Clinically significant macular edema (n = 4) was correctly identified in 15 of the 24 grading re p o rts. An additional seven re p o rts re f e rred the patients for furt h e r investigation because of concurrent diabetic re t i n o p a t h y.C O N C L U S I O N S -Te l e s c reening for diabetic retinopathy by an assessment of two-field 50°n o n -s t e reo digital images is a valid screening method. Although detection of clinically significant macular edema using biomicroscopy is superior to digital or standard non-stereo photographs, only few patients with sight-threatening diabetic retinopathy are missed. E m e r g i n g T r e a t m e n t s a n d T e c h n o l o g i e s Diabetes Care 346DIABETES CARE, VOLUME 23, NUMBER 3, MARCH 2000 Telemedical screening of diabetic retinopathyThe 65 patients who did not part i c ipate were older (59.0 ± 16.0 years), had a longer duration of diabetes (17.6 ± 12.4 years), and had more severe re t i n o p a t h y (43% no, 33% mild or moderate, and 24% s i g h t -t h reatening diabetic retinopathy). The p ro p o rtion of men (50%) and patients with type 2 diabetes (58%) did not differ fro m the included patients. These patients were examined by an ophthalmologist only. Experimental protocolAfter the assessment of best corrected visual a c u i t y, each patient was screened for the p resence of diabetic retinopathy after dilation of pupils (tropicamide 1%) and subsequent slit-lamp biomicroscopy by an experienced ophthalmologist. During the study period, six senior ophthalmologists, not specializing in diabetic re t i n o p...

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Diabetic retinopathy is one of the leading causes of blindness in the western world (Munier et al 1998). The challenges for improving the visual prognosis in this disease are comprehensive, and involve a multitude of methodological approaches. Thus, ongoing research programmes are aimed at studying as diverse aspects of diabetic retinopathy as epidemiology, genetics, screening, diagnosis, treatment, and understanding of the pathophysiology of the disease. This review presents the scientific approach followed at Aarhus University Hospital in relation to three of these aspects-epidemiology, computerised grading, and elucidation of the pathophysiology of diabetic retinopathy.

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Purpose Glaucoma is a neurodegenerative disorder with loss of retinal ganglion cells and axons. Elevated intraocular pressure is a significant risk factor in the development of glaucoma. Aqueous humour secretion is in part maintained by the aquaporins (AQPs) and AQPs also regulate fluid homeostasis in the retina. We investigate the expression of AQP1, ‐3, ‐4, ‐5, ‐7 and ‐9 in human glaucoma eyes compared to control normal eyes. Methods Immunohistochemistry for AQP1, ‐3, ‐4, ‐5, ‐7 and ‐9 was performed on human paraffin embedded eyes. Nine glaucoma eyes were examined comprising three eyes diagnosed with simplex glaucoma, three eyes with neovascular glaucoma and three eyes with chronic angle closure glaucoma. The six control eyes had normal intraocular pressure without glaucoma. From each immunohistochemical slide representative fields (x20 objective) within the eye were captured. Using Photoshop software optical densities were generated and indices of staining intensity were calculated. Results Immunostaining showed labeling of AQP7 in the Müller cell endfeet with an increased intensity in glaucoma eyes (p=0,02). AQP9 labeling of the retinal ganglion cells showed decreased intensity per cell (p=0,005). In the optic nerve there were no difference in AQP1, AQP4 and AQP9 labeling in the optic nerve astrocytes between normal and glaucoma eyes Conclusion This is the first study investigating the AQPs in human glaucoma eyes. We found a reduced expression of AQP9 in retinal ganglion cells in glaucoma eyes. Glaucoma also induced increased AQP7 expression in the Müller cell endfeet. These results suggest that changes in retinal AQP expression are associated with the development of glaucoma

Background Diabetic retinopathy can be treated by retinal photocoagulation. The treatment may induce discomfort and pain, and due to the individual variation of these adverse effects, it is a challenge to inform patients and to minimise discomfort during treatment. Methods The subjective sensation of pain was evaluated on a numeric rating scale from 0 – 10 in 235 successive patients receiving macular photocoagulation (MP) and 174 patients receiving panretinal photocoagulation (PRP). The influence of first/second eye, treatment session, gender, age, diabetic type, diabetic treatment, duration of diabetes, mean arterial pressure (MAP), body mass index (BMI), glycosylated haemoglobin (HbA1c), visual acuity, right/left eye, number, spot size and effect of applications on the perceived pain was studied. Results The pain score was significantly lower (p<0.001) after the first treatment in the first eye in patients treated with MP 1.67 ±1.8, n=235 (mean ±SD, n) than in patients treated with PRP 2.67 ±2.4, n=174 (mean ±SD, n). Lower mean arterial pressure, higher HbA1c and higher number and effect of the applications contributed significantly to increasing the reported pain during the first treatment in the first eye. For all patients treated in both eyes the reported pain was significantly (p<0.001) higher in the second 2.74 ±2.40, n=269 (mean ±SD, n) than in the first 2.08 ±2.14, n=269 (mean ±SD, n) eye. The pain was significantly higher during the two last than during the first treatment session in patients who received panretinal photocoagulation (p<0.001). Conclusions The higher pain during high treatment intensity and treatment in the retinal periphery might prompt a fractioning of treatment in patients with a low pain threshold. The increased pain with increasing HbA1c and decreasing MAP might be used to individualize information about treatment and to prepare health care professionals about the reactions of the patients.

SummaryIt has been shown that the oxygen saturation in retinal vessels is increased in patients with diabetic maculopathy, but the role of this parameter for the effect of anti‐VEGF treatment of the disease is unknown. Therefore, the predictive value of oxygen saturation in larger retinal vessels for the effect of anti‐VEGF treatment of diabetic maculopathy was studied. In 73 eyes from 53 patients with center involving diabetic macular edema the predictive value of oxygen saturation in larger retinal vessels and other risk factors for retinopathy progression as explanatory variables was studied for visual acuity (VA) and central retinal thickness (CRT) after anti‐VEGF treatment as effect variables. Anti‐VEGF treatment induced a significant increase in VA and a signficant decrease in CRT, but no significant changes in the overall oxygen saturation of larger retinal vessels. In a multiple regression model VA and CRT obtained before treatment contributed significantly to predicting the effect of treatment on the same variable. Mean arterial blood pressure and the oxygen saturation in retinal arterioles before treatment contributed signficantly to predicting both VA and CRT after treatment. The oxygen saturation in retinal arterioles is a new parameter that might potentially be included in risk models predicting the effect of anti‐VEGF treatment on diabetic maculopathy.

PurposeMean retinal venous oxygen saturation (VSatO2) has been found to be different from normal in several retinal diseases. There are speculations that metabolic imaging of the retina could be helpful in monitoring such diseases and perhaps help with diagnosis. The aim of the study was to characterize normal range of retinal VSatO2 and to further examine patients that fall outside normal range.MethodsRetinal vessel oxygen saturation was measured in healthy individuals (n = 89), patients with glaucoma (n = 78), retinitis pigmentosa (RP, n = 10), diabetic retinopathy (DR, n = 54) and central retinal vein occlusion (CRVO, n = 14). Measurements were performed with a spectrophotometric retinal oximeter, Oxymap T1.ResultsFifty‐four healthy individuals were age‐ and gender matched with DR and CRVO patients. For this healthy group, 5% of VSatO2 were below 38 and 5% of VSatO2 were above 63%. Eleven CRVO patients (79%) had lower than 38% VSatO2. Twenty‐five DR patients (46%) had VSatO2 above 63% and the ratio of those outside normal limits increased with severity of retinopathy. Mean VSatO2 was lower in CRVO patients and higher in DR compared to healthy (p < 0.0001 for both comparisons). Eighty‐nine healthy individuals that were 60 years and older were compared to glaucoma and RP patients. In this healthy group, 5% of VSatO2 were above 64%. Six glaucoma (8%) and two RP patients (20%) had VSatO2 higher than 64%. Mean VSatO2 was higher in advanced glaucoma (p = 0.007) and RP (p = 0.05) compared to healthy.ConclusionsMost CRVO patients have VSatO2 below the normal limit. Although there is overlap in VSatO2 between patients with DR and normal, a considerable proportion of DR patients fall outside the normal range. Most of the patients with glaucoma and RP were within normal limits for VSatO2.