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Fundus Camera (fundu + camera)
Selected AbstractsRetinal vascular findings and penile cavernosal artery blood flowBJU INTERNATIONAL, Issue 9 2003Y. Kawanishi Authors from Japan attempt to correlate retinal vascular changes with cavernosal arterial blood flow. They studied patients with erectile dysfunction, but excluded patients with previous pelvic surgery, pelvic injury or diabetes. They found that penile changes can be anticipated from retinal vascular changes seen on fundoscopy. OBJECTIVE To assess the correlation between retinal vascular findings and penile cavernosal arterial blood flow, as it is probable that systemic atherosclerotic vascular disease is important in male erectile dysfunction (ED), and being systemic, it might be possible to evaluate the extent of atherosclerosis from retinal vascular findings. PATIENTS AND METHODS The study included 75 patients with ED; any with a history of pelvic injury, pelvic surgery, or diabetes mellitus were excluded. All patients gave fully informed consent. Ocular fundus photographs were taken with an automatic-focus fundus camera under amydriatic conditions. Three ophthalmologists, unaware of the patients' detailed data, evaluated the photographs using Hyman's classification to evaluate retinal vascular findings. Blood flow in the penile cavernosal artery was measured with colour Doppler ultrasonography, and the peak systolic velocity used as a haemodynamic variable. Correlations among the peak systolic velocity, retinal vascular findings and vascular risk factors (including hypertension, age, cigarette smoking, and hyperlipidaemia) were investigated using multivariate analysis. RESULTS Of the 75 patients, 72 (96%) had both right and left retinal vascular images of sufficient quality for evaluation; 37 were classified as normal and 35 as Grade I, while no patient was Grade II. From a logistic regression multivariate analysis, the peak systolic velocity was the only significant factor correlating with retinal vascular findings, with an odds ratio of 3.34. In contrast, hypertension, age, cigarette smoking and hyperlipidaemia did not correlate significantly with the retinal vascular findings. Similarly, the retinal vascular finding was the only significant factor correlating with the peak systolic velocity of cavernosal blood flow (odds ratio 3.28) and again hypertension, age, cigarette smoking and hyperlipidaemia were not significant factors. CONCLUSIONS These findings support the assumption that penile erectile function is one of the diseases of atherosclerosis, and emerges nearly simultaneously with retinal vascular disease. It is possible to predict penile arterial conditions in patients with ED from their retinal vascular findings. Thus, amydriatic fundoscopy, a simple practical examination, may be helpful for primary physicians in diagnosing and treating ED. [source] 2321: Retinal vessel diameter affects oxygen saturation measurementsACTA OPHTHALMOLOGICA, Issue 2010SH HARDARSON Purpose To test whether retinal vessel oxygen saturation measurements are affected by vessel diameter and to compare saturation between the temporal and nasal retina. Methods The Oxymap retinal oximeter is based on a fundus camera. It measures light absorbance at two wavelengths of light and calculates oxygen saturation in retinal vessels as well as vessel diameter. Measurements were performed on 12 healthy individuals. The effect of vessel diameter on saturation measurements was tested by measuring before and after the first bifurcation in the retina (1st degree parent vessels and 2nd degree daughter vessels). Arteriolar saturation can be assumed to be equal before and after bifurcation. Results The ratio between oxygen saturation in 1st degree parent arteriole and 2nd degree daughter arteriole was 0.97±0.02 (mean±SD). The ratio was significantly lower than the theoretical value of 1.00 (p<0.001, n=12) The corresponding ratio for venules was 0.90±0.04 (p<0.001). Oxygen saturation was 94±6% in 1st degree superotemporal arterioles and 99±6% in superonasal arterioles (p=0.057). Oxygen saturation in inferotemporal arterioles was 89±6% and 95±4% in inferonasal arterioles (p=0.009). There was no significant difference in venous saturation between temporal and nasal quadrants. Conclusion Measured oxygen saturation is lower in 1st degree parent vessels than in their 2nd degree daughter branches. This indicates that retinal vessel diameter affects oxygen saturation measurements. The higher measured saturation in the nasal arterioles, compared to temporal arterioles, may also be due to the fact that the nasal vessels are narrower. A correction for the effect of vessel diameter should be incorporated into oxygen saturation measurements. Commercial interest [source] 2322: Reproducibility of retinal vessel hemoglobin oxygenation saturation in healthy subjectsACTA OPHTHALMOLOGICA, Issue 2010M LASTA Purpose Only recently systems for the measurement of hemoglobin oxygenation saturation in retinal vessels became commercially available. In the present study a fundus camera equipped with a dual wavelength transmission filter and a CCD camera was used (Imedos, Jena, Germany). Two monochromatic fundus images at 548 and 610 nm were recorded simultaneously and the oxygen saturation (SaO2) was calculated based on the optical density ratio. Methods A study on test/retest, short-term and day-to-day reproducibility of the technique was done in 14 healthy subjects. To assess test/retest variability fundus images were taken at each measurement cycle. To assess short-term reproducibility 2 such cycles of 3 fundus images were done within 15 minutes. Finally, this cycle of measurements was done on the next day to assess day-to-day reproducibility. Data were evaluated separately for retinal branch arteries and branch veins. The reproducibility was calculated using the standard deviation (SD) of the measurements. Results In retinal branch veins the SaO2 was 49±9% (range 32-69%, 38 vessels) and in retinal branch arteries 91±8% (range 77-112%, 40 vessels). The test/retest SD was 5.4±3.7% in retinal veins and 3.0±2.3% in retinal arteries. The short term SD was 4.7±3.7% in retinal veins and 2.9±2.1% in retinal arteries. The day-to-day SD was 6.2±4.1% in retinal veins and 4.0±2.8% in retinal arteries. Conclusion Our data indicate that the test/retest, short-term and day-to-day reproducibility of the technique is acceptable. Hence, the system may be adequate to follow oxygen saturation during disease processes. The data obtained in retinal branch arteries indicates, however, that the validity of measurements requires further studies. [source] 2324: Comparison of algorithms for oximetry in vivo and ex vivoACTA OPHTHALMOLOGICA, Issue 2010D DE BROUWERE Purpose Several authors have proposed a number of algorithms to extract the oxygen saturation in retinal blood vessels based on multispectral image analysis. We evaluated the outcomes of seven known algorithms based on hyperspectral retinal images. Methods Hyperspectral images are acquired using a fundus camera where a slit spectrograph is registered onto a retinal image. This combination compromises both accurate spatial and spectral information over the selected slit. Hyperspectral image analysis was used as input for the oximetry calculations described in the literature. We used a model eye to evaluate the different techniques in a controlled setup. Defibrinated horse blood was perfused through microtubules placed in front of a white (spectralon) background. Oxygen saturation was controlled by mixing different concentrations of sodium dithianate in the blood. Results Oxygen saturation was varied in five equidistant steps between 0 and 1. We correlated the outcomes to the metric of Harvey et al. [Biomed Optics 6631, 2007] Linear correlation with other algorithms resulted in r2 values between 0.881 and 0.985, however we observed a large discrepancy of the slope of each correlation line. The algorithms were also evaluated in images recorded in five healthy volunteers. In all techniques, veins could be separated from arteries by their reduces oxygen saturation, although values varied strongly between the different techniques. Conclusion Our findings confirm the working of a number of noninvasive retinal oximetry algorithms. Different readings can be can be attributed to an offset caused by an uncertainty of pigmentation and scattering parameters in the calibration procedure. [source] Retinal oxygenation in diabetic retinopathyACTA OPHTHALMOLOGICA, Issue 2009SH HARDARSON Purpose Diabetic retinopathy (DR) is believed to cause retinal tissue hypoxia by damaging retinal capillaries. The purpose of this study was to examine the effect of diabetic retinopathy on oxygen saturation in retinal arterioles and venules. Methods The retinal oximeter (Oxymap ehf., Reykjavik, Iceland) is composed of a fundus camera, beam splitter and light filters. Specialized software calculates relative oxygen saturation from light absorption at two wavelengths of light (605nm and 586nm). One first or second degree temporal arteriole and venule were measured in one eye of 31 healthy individual and 28 patients with diabetic retinopathy. The diabetic patients had background DR (n=6), macular oedema (n=7), untreated preproliferative or proliferative DR (n=7) or stable proliferative DR after treatment (n=8). Statistical analyses were performed with an unpaired t-test, one-way ANOVA and Dunnett's post test. Results Retinal arteriolar saturation was 93±4% (n=31, mean±SD) in healthy subjects and 101±6% (n=28) in patients with DR (p<0.0001). Retinal venular saturation was 58±6% in healthy subjects and 67±8% in diabetic patients (p<0.0001). Arteriolar and venular saturation was higher in all subgroups of diabetic patients (see methods) than in healthy subjects. Conclusion Increased oxygen saturation in retinal vessels in diabetic retinopathy, also found by other researchers, is consistent with poor distribution of blood and oxygen to the retinal tissue rather than decreased total retinal blood flow. Poor distribution of oxygen may be caused by capillary dropouts and shunts as well as thickening of the capillary walls. Commercial interest [source] Noninvasive oximetry and glaucomaACTA OPHTHALMOLOGICA, Issue 2009OB OLAFSDOTTIR Purpose To investigate retinal vessel oxygen saturation in relation to glaucomatous visual field damage. Specifically, we examined whether oxygen saturation in retinal blood vessels differs between regions corresponding to glaucomatous visual field defects compared to regions without visual field defects. Methods A spectrophotometric retinal oximeter (Oxymap ehf, Reykjavík, Iceland) was used to measure oxygen saturation in retinal arterioles and venules. The oximeter consists of a fundus camera, beam splitter, light filters and software that evaluate the oxygen saturation. The glaucomatous defect was estimated from a visual field test using the Octopus 1-2-3 perimeter. One eye in 13 individuals with open angle glaucoma with or without pseudoexfoliation syndrome was examined. Results In retinal areas with no visual field defect, the mean oxygen saturation in arterioles was 102±6% and 65±9%, (mean±SD) in venules. The arteriovenous difference was 37±10%. In retinal areas corresponding to visual field defects, the mean oxygen saturation in arterioles was significantly lower; 98±5% (p=0.04, paired t-test, n=13). The venules were at 68±7% (p=0.3) and the arteriovenous difference was also significantly lower; 30±10% (p=0.04). Conclusion Arteriolar oxygen saturation and arteriovenous difference is statistically lower in areas with visual field defects compared to areas without visual field defects. This data suggests that visual field defects are associated with a reduction in retinal oxygen delivery and metabolism. [source] Retinal vessel oximetry using sequential and 'snapshot' hyperspectral imagingACTA OPHTHALMOLOGICA, Issue 2009A MCNAUGHT Purpose Use of sequential, and 'snapshot' hyperspectral imagers to measure oxygen saturation in retinal vessels in normals, and examples of eye disease, eg glaucoma, and retinovascular diseases. Validation of estimated oximetry values using a model eye. Methods A sequential hyperspectral imager was constructed using a fundus camera with built-in liquid-crystal tuneable filter. Images of normals,and ocular disease are presented. A novel 'snapshot' hyperspectral imager is also described: this produces images in a single exposure. Validation of both devices using an artificial eye with capillary tubes containing human blood of known oxygen saturation, placed in front of an 'artificial retina' is described. The image analysis used to detect retinal vessels, and generate oximetric values is detailed. Results Both the sequential, and 'snapshot' retinal imagers produced accurate estimations of retinal vessel oxygen saturation, when compared with the model eye. Imaging of a small group of glaucoma eyes showed abnormally elevated venous oxygen saturation. In proliferative diabetic retinopathy, abnormally elevated venular saturation was found in areas of capillary loss on FFA. In vein occlusion, elevated venous saturation was found in eyes with ischaemic FFAs. Conclusion Both the sequential and 'snapshot' hyperspectral imagers deliver useful oximetric maps of the retina. The 'snapshot' device allows more rapid imaging. The elevated venular oxygen saturation seen in both glaucoma, and retinovascular disease, is perhaps evidence of reduced oxygen consumption in damaged inner retina in glaucoma, and/or vascular 'shunting' in retinovascular disease. [source] Marginal crack after intravitreal bevacizumab for myopic choroidal neovascularizationACTA OPHTHALMOLOGICA, Issue 4 2009Kaori Sayanagi Abstract. Purpose:, To report new indocyanine green angiographic (ICGA) findings after intravitreal bevacizumab (IVB) for myopic choroidal neovascularization (mCNV). Cases report:, Three eyes of three patients with mCNV were examined with fluorescein angiography (FA) and ICGA using Heidelberg Retinal Angiograph 2 and the conventional fundus camera before and after IVB. The cessation of angiographic leakage on FA was achieved in all eyes (100%) after IVB, however the hypofluorescent line delineating the margin of the neovascular tissue appeared in ICGA seemingly according to the contraction of mCNV. It was not detected either on FA or ICGA with the conventional camera. This hypofluorescence line enlarged over the time. Conclusion:, The contraction-associated hypofluorescence line, namely marginal crack line, indicates the early damage of retinal pigment epithelium and seems to lead to expanding macular chorioretinal atrophy typically seen in mCNV. [source] The analysis of fundus autofluorescence patterns in retinal diseasesACTA OPHTHALMOLOGICA, Issue 2007P POPOVIC Purpose: Fundus autofluorescence (AF) imaging is a method that shows accumulation of lipofuscin in the retinal pigment epithelium cells in vivo. Fundus AF may be recorded in retinal diseases either by scanning laser ophthalmoscope or by fundus camera using the appropriate filter. The aim of this study was to analyze the AF pattern by both methods. Methods: 20 patients with different retinal diseases including retinitis pigmentosa, cone-rod dystrophy, Stargardt disease, Best macular dystrophy, central serous retinopathy and age-related macular degeneration were included in the study. AF images were obtained from each subject using a confocal scanning laser ophthalmosope and digital fundus camera. The distribution and amount of AF were compared by the use of both systems. Results: In all disease entities both instruments showed distinct pattern of AF typical for the disease. Areas of high intensity of AF recorded with HRA matched to areas of increased intensity of AF detected with fundus camera. The distribution of areas of low or absent AF also corresponded well in both systems. Images taken with conventional fundus camera were in general lower contrasted and therefore less sharp. This was particularly true for patients with even mild media opacity. The advantage of fundus camera was however a recording of AF of a greater field of view. Conclusions: AF imaging is a very useful noninvasive method for detecting RPE abnormalities. In clinical practice, when scanning laser ophthalmoscope for recording of AF is not available, conventional digital fundus camera can be used for screening of patients suspected to have retinal disease. Care should be taken in patients with nuclear cataract, as the AF image is influenced by the AF of the crystalline lens by a great amount. [source] Optic nerve head parameters of an indigenous population living within Central AustraliaCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 9 2006John A Landers MBBS MPH Abstract Purpose:, Clinical examination of the optic disc is an essential element in the assessment of its health. Previous work has described normal optic disc appearance among different races. No such description of optic discs exists for indigenous Australians, who are at low risk of developing glaucoma. This study was designed to evaluate optic disc parameters of indigenous Australians. Methods: A sample of 208 indigenous Australians were recruited as they presented to remote clinics in Central Australia. Each subject underwent optic disc photography using a Topcon TRC-NW100 digital fundus camera. Optic discs were measured and analysed with Topcon ImageNet 2000 software. Results: Among other parameters, mean vertical disc diameter and disc area were 2.13 ± 0.21 mm (mean ± SD) and 3.13 ± 0.57 mm2, respectively, for right eyes and 2.14 ± 0.21 mm and 3.16 ± 0.58 mm2 for left eyes. When compared with published studies, these parameters were significantly larger than Caucasians, but similar to African individuals. Conclusion:, Our results suggest that indigenous Australians have optic discs that are larger than those of Caucasians, but similar to those of Africans who are considered to at a greater risk of glaucoma. Factors other than optic disc area are likely to underlie the higher prevalence of primary open angle glaucoma among African individuals. [source] Methods for detecting age-related maculopathy: a comparison between photographic and clinical assessmentCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 5 2000Gabriella Tikellis GradDip ABSTRACT Purpose: To examine the sensitivity, specificity and overall agreement between photographic and clinical assessment in detecting age-related maculopathy (ARM) features in the context of an epidemiological study, the Vitamin E, Cataract and Age-related Maculopathy Study (VECAT). Methods: A total of 1204 volunteers aged between 55 and 80 years of age, who were enrolled in the VECAT Study, had both slit-lamp biomicroscopy examination and fundus photos taken as part of the baseline ophthalmic examination. The Nidek 3-DX fundus camera (Nidek, Gamagori, Japan) was used to produce paired, one-framed, coloured, 15° stereoslides of the macular area at a fixed angle. An International Classification and Grading System for Age-related Maculopathy and Age-related Macular Degeneration was used to grade the stereoslides. Agreement in the detection of drusen, pigment abnormalities, and late stage ARM features was assessed using unweighted kappa statistic. Cases of disagreement were verified using clinical data records, grading documentation and the review of stereoslides. Results: Macula status was available for 2386 eyes. For drusen of size < 63 ,m, sensitivity was 47%, specificity was 68% with a kappa value of 0.20. For drusen , 125 ,m, sensitivity and specificity were , 81%. Kappa values ranged from 0.56 to 0.71. Levels of agreement for pigment abnormalities and late ARM were in the substantial range (i.e. kappa values from 0.70 to 1.00). Conclusions: Slit-lamp biomicroscopy was found to be comparable to photograding (using the Nidek 3-DX fundus camera) for detecting features pertaining to ARM. However, given the objectivity and permanency of stereoslides, photograding is still the more reliable and the preferred system of assessing ARM in the context of an epidemiological study. [source] Fred Hollows lecture: Digital screening for eye diseaseCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 3 2000Ij Constable ABSTRACT The purpose of this study was to explore progress, in the adaptation to community screening for blinding eye disease, of digital imaging devices and technology for storage and transmission. Available imaging systems were compared to gold standard clinical photography in terms of sensitivity and specificity for diagnosis of common blinding eye conditions. Since the use of expensive non-portable imaging devices is likely to be limited for widespread community screening purposes, a portable fundus camera (Nidek, Chiyoda-ku, Japan) and a prototype monocular digital indirect ophthalmoscope constructed at the Lions Eye Institute (LEI) were selected for comparative trials for the screening of optic disc cupping, glaucoma and clinical signs of diabetic retinopathy. Fifty-one eyes of 27 consecutive patients being assessed at the LEI clinic for glaucoma were dilated and photographed with a Zeiss retinal camera, and digital images were taken with the portable Nidek NM100 fundus camera (Carl Zeiss, Oberkochen, Germany) or with a prototype digital monocular indirect ophthalmoscope. Vertical cup : disc ratios (VCDR) were measured on the disc photographs by one ophthalmologist while three other clinicians were presented with compressed digital images in random order to estimate VCDR. Field trials were also carried out to demonstrate the practicality of compression, local storage and then transmission by mobile telephone ISDN lines and satellite, of optic discs and fundus images of patients with diabetes in either rural Western Australia or Surabaya, Indonesia. Kappa values of correlations of measurement of agreement between measured and estimated VCDR were 0.87, 0.45 and 0.84, respectively, for the three observers, corresponding to a specificity of 79,97% and a sensitivity of 70,95%. The portable Nidek fundus camera was also assessed for specificity and sensitivity in the diagnosis of diabetic retinopathy in comparison to standard Zeiss fundus camera photographs. Of 49 eyes in 25 consecutive patients attending the LEI clinic for assessment of diabetic retinopathy, three ophthalmologists assessed photographs and images in random order. When used for screening diabetic retinopathy, the digital images of the Nidek camera were graded as adequate quality in only 56% of eyes compared to 93% of the photographs. The kappa value of agreement in analysis of diabetic retinopathy was only 0.30. The prototype digital monocular indirect ophthalmoscope compared favourably with the Nidek camera. At 1:5 compression, images of size 36 kB transmitted from Surabaya to Perth took 29 s on the mobile telephone, while uncompressed images took 170 s. Images compressed 1:5 were transmitted in 60 s using the satellite telephone, while the uncompressed images took 240 s. Satellite transmission was more expensive but the lines were more stable than telephone connections from Indonesia. Digital imaging is becoming a powerful tool for ophthalmology in clinical records, teaching and research, and interoffice diagnostic opinions. It also has enormous potential for community screening for blinding eye diseases, such as glaucoma and diabetic retinopathy. Inexpensive portable imaging devices that are easy to use, and on which local health workers might be trained, must be developed and validated in terms of sensitivity and specificity of performance. The technology of image capture, image compression, transmission, data base storage and analysis is rapidly evolving and becoming less expensive. [source] Clinical use and research applications of Heidelberg retinal angiography and spectral-domain optical coherence tomography , a reviewCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 1 2009Andrea Hassenstein MD Abstract Fluorescein angiography (FA) was discovered by Nowotny and Alvis in the 1960s of the 20th century and has evolved to become the ,Gold standard' for macular diagnostics. Scanning laser imaging technology achieved enhancement of contrast and resolution. The combined Heidelberg retina angiograph (HRA2) adds novel innovative features to established fundus cameras. The principle of confocal scanning laser imaging provides a high resolution of retinal and choroidal vasculature with low light exposure providing comfort and safety for the patient. Enhanced contrast, details and image sharpness image are generated using confocality. For the visualization of the choroid an indocyanine green angiography (ICGA) is the most suitable application. The main indications for ICGA are age-related macular degeneration, choroidal polypoidal vasculopathy and choroidal haemangiomas. Simultaneous digital FA and ICGA images with three-dimensional resolution offer improved diagnosis of retinal and choroidal pathologies. High-speed ICGA dynamic imaging can identify feeder vessels and retinal choroidal anastomoses, ensuring safer treatment of choroidal neovascularization. Autofluorescence imaging and fundus reflectance imaging with blue and infrared light offer new follow-up parameters for retinal diseases. Finally, the real-time optical coherence tomography provides a new level of accuracy for assessment of the angiographic and morphological correlation. The combination of various macular diagnostic tools, such as infrared, blue reflectance, fundus autofluorescence, FA, ICGA and also spectral domain optical coherence tomography, lead to a better understanding and improved knowledge of macular diseases. [source] | ||||||||||