PURPOSE Acetazolamide was previously shown to increase optic disc partial pressure of oxygen (PO(2)). The study was conducted to evaluate optic disc PO(2) variations during normoxia, hyperoxia (100% O(2)), and carbogen breathing (95% O(2), 5% CO(2)), before and after intravenous administration of acetazolamide. METHODS PO(2) measurements were obtained at intervascular areas of the optic disc ...

OBJECTIVE To determine the prevalence of tilted and torted optic discs and associated risk factors among Chinese adults in Singapore. METHODS As part of a population-based survey, optic disc stereophotographs of both eyes were obtained, and left eyes were analyzed using imaging software. A tilted optic disc was defined as an index of tilt (ratio of minimum to maximum optic disc diameter) less...

Optic disc (OD) and fovea locations are two important anatomical landmarks in automated analysis of retinal disease in color fundus photographs. This paper presents a new, fast, fully automatic optic disc and fovea localization algorithm developed for diabetic retinopathy (DR) screening. The optic disc localization methodology comprises of two steps. First, the OD location is identified using t...

There are many systemic diseases that affect the functioning and working of the eye. Some of the major parts of the eye like iris, retina, and optic nerve are affected due to systemic diseases like diabetes, AIDS, glaucoma, hypertension, macular degeneration, swelling in the brain and many more. Glaucoma is the condition of eye caused by increase in intraocular pressure. Early detection of this...

PURPOSE To evaluate the effect of race (African or European descent), age, disc area, and severity of disease on the diagnostic ability of spectral-domain optical coherence tomography (SDOCT) imaging of the optic nerve, macula, and retinal nerve fiber layer (RNFL) in the detection of glaucomatous injury. METHODS In this cross-sectional observational study, data from SDOCT images of 312 eyes o...

PURPOSE To evaluate the validity of different methods of relative afferent pupillary defect (RAPD) detection and assess the usefulness of detecting an RAPD in glaucoma patients. METHODS For this prospective observational study, we enrolled 70 of 153 consecutive glaucoma patients coming for examination. Exclusion criteria were cloudy corneas, recent surgery, fixed pupils, and other diseases pr...

AIMS To find out whether the size of the blind spot area, determined by static perimetry, depends on the surface topography of the optic disc and its surrounding area. METHODS Ten eyes were examined; all had a parapapillary atrophy adjacent to the temporal side of the disc. Microperimetry was performed under direct fundus control using a Rodenstock scanning laser ophthalmoscope. The horizonta...

PURPOSE To investigate optic disc perfusion differences in normal, primary open-angle glaucoma (POAG), and normal tension glaucoma (NTG) eyes using optical microangiography (OMAG) based optical coherence tomography (OCT) angiography technique. DESIGN Cross-sectional, observational study. SUBJECTS Twenty-eight normal, 30 POAG, and 31 NTG subjects. METHODS One eye from each subject was scan...

PURPOSE To examine the roles of genetic and environmental factors in the optic disc in a classic twin study. METHODS Five hundred six pairs of twins were recruited to participate from the Twins U.K. Adult Twin Registry at St. Thomas' Hospital, London. Photographs of the optic disc were obtained, and the covariance of optic disc, cup, and rim areas within monozygotic (MZ) and dizygotic (DZ) pa...

The purpose of this study was to evaluate the relationship between central corneal thickness (CCT) and optic disc morphology in normal tension glaucoma (NTG). Patients with NTG underwent eye examination, optic disc imaging with Heildelberg Retina Tomograph II (HRT II) and ultrasound corneal pachymetry. The morphological parameters of the optic discs were used to classify the eyes into four grou...