Image size in the fundus: structural evidence for wide-field retinal magnification factor.
نویسندگان
چکیده
A simple geometrical method is described of calculating the retinal magnification factor (micrometres/degree) at the ora serrata of the human eye. At the ora the magnification factor is some 176 microns/deg., whereas at the posterior pole it is 276 microns/deg. This result may be of clinical use in examinations where dimensions of tears and holes near the ora serrata are estimated.
منابع مشابه
Early Detection of Diabetic Retinopathy in Fluorescent Angiography Retinal Images Using Image Processing Methods
Introduction: Diabetic retinopathy (DR) is the single largest cause of sight loss and blindness in the working age population of Western countries; it is the most common cause of blindness in adults between 20 and 60 years of age. Early diagnosis of DR is critical for preventing vision loss so early detection of microaneurysms (MAs) as the first signs of DR is important. This paper addresses th...
متن کاملMorphological Exudate Detection in Retinal Images using PCA-based Optic Disc Removal
Diabetic retinopathy lesion detection such as exudate in fundus image of retina can lead to early diagnosis of the disease. Retinal image includes dark areas such as main blood vessels and retinal tissue and also bright areas such as optic disk, optical fibers and lesions e.g. exudate. In this paper, a multistage algorithm for the detection of exudate in foreground is proposed. The algorithm se...
متن کاملInvestigation of the Spatial Resolution and Field of View with Change of Magnification in VRX CT
Introduction: Variable resolution x-ray (VRX) CT is a new type of CT that can image objects at various spatial resolutions. In a VRX CT scanner, the spatial resolution increases at the cost of reduction in the field of view (FOV). An important factor that limits the spatial resolution of the VRX CT is the effect of focal spot size. Also, the optimum magnification is different at each incident a...
متن کاملNonoptical determinants of aniseikonia.
Interocular differences in apparent size (aniseikonia) are typically associated with interocular differences in refractive error (anisometropia). Aniseikonia is generally thought to reflect disparities in retinal image size that often accompany anisometropia. This assumption was examined with seven highly anisometropic subjects who were tested under conditions in which no substantial retinal im...
متن کاملAutomatic Detection of Microaneurysms in Color Fundus Images using a Local Radon Transform Method
Introduction: Diabetic retinopathy (DR) is one of the most serious and most frequent eye diseases in the world and the most common cause of blindness in adults between 20 and 60 years of age. Following 15 years of diabetes, about 2% of the diabetic patients are blind and 10% suffer from vision impairment due to DR complications. This paper addresses the automatic detection of microaneurysms (MA...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- The British journal of ophthalmology
دوره 72 3 شماره
صفحات -
تاریخ انتشار 1988