Ocular Fundus Photography Research Articles

Position of the fovea centralis with respect to the optic nerve head.

Examination of the ocular fundus via indirect ophthalmoscopy gives the clinician an impression of foveal position relative to the nerve head. In some patients, the fovea appears to be in an unusual position (i.e., ectopic): it may appear to be higher or lower than expected, or closer to or farther from the nerve head. There is little published quantitative information on this subject. The purpose of this study was to examine foveal position in a group of normal adult eyes, so that clinicians and other researchers will be able to determine on a more objective basis whether or not a given patient shows foveal ectopia. Using ocular fundus photographs for 446 normal adult eyes, we found the foveal center to be, on average, 6.11 degrees +/- 3.32 degrees below a horizontal line bisecting the nerve head. For a smaller sample of 66 eyes, we found the average distance between the nerve head and foveal centers to be 4.93 +/- 0.33 mm (right eye) and 4.88 +/- 0.36 mm (left eye). Correlations of these data for right and left eyes are also examined. Nerve head data for the group of 66 right eyes were also analyzed to yield dimensions of a best-fitting ellipse: the mean minor axis was 1.75 +/- 0.2 mm; the mean major axis 1.95 +/- 0.2 mm. Ectopia (heterotopia) of the fovea has been found in association with chorioretinitis, fibrous traction bands, and/or colobomas of the choroid and optic nerve (including anomalous insertion of the optic nerve), microcephalus, and microphthalmia. A number of separate cases with anomalous nerve heads and/or foveal positions are discussed in this paper.(ABSTRACT TRUNCATED AT 250 WORDS)

Longitudinal Study of Lesions of the Posterior Segment in Onchocerciasis

Onchocerciasis is a major cause of blindness, and much of the blindness due to onchocerciasis is caused by chorioretinitis. Little is known about the progression of lesions in the posterior segment in either untreated or treated disease. The authors studied the progression of onchocercal chorioretinitis in 57 patients from 1 to 3 years. Changes were documented from detailed ocular examinations, fundus photographs, and fluorescein angiograms, and included live intraretinal microfilariae, intraretinal hemorrhages, cotton-wool opacities, intraretinal pigment, white and shiny intraretinal deposits, retinal pigment epithelial window defects, and atrophy. Depigmentation at the edge of chorioretinal scarring progressed at a rate of up to 200 µm per year. Ivermectin or mebendazole treatment did not appear to alter the progress of depigmentation at the edge of chorioretinal scars. These observations suggest that onchocercal chorioretinitis is associated with early changes in the retina and retinal pigment epithelium, and that disease in the posterior segment may progress rapidly.

Elliptical features of the human optic nerve head.

Ocular fundus photographs of the optic nerve head of 396 normal eyes were obtained. An ellipse was fitted to points digitized around the circumference of each nerve head. The length of the major and minor axes, and the orientation of the major axes were determined. This paper gives frequency distributions for the degree of ellipticalness of 396 nerve heads. The long axis is on average 11.5% longer than the short axis and the top of the long axis tends on average to be tilted toward the midline of the head by 10 degrees. In addition, it appears that the population of Elschnig type III nerve heads includes higher elliptical values than that for the Elschnig type II nerve heads.

Microscope ocular fundus photography.

The ocular of any microscope may be used for the purpose of photography through the device if the camera utilizes the given optical conditions like an observer eye concerning aperture and focal length.

The clinical significance of the asymptomatic Hollenhorst plaque

Sixty consecutive patients with visual complaints as the primary symptom of cerebrovascular insufficiency were evaluated with complete cerebral angiography (CCA). Eighteen patients referred for evaluation of asymptomatic Hollenhorst plaques had a 50% incidence of ipsilateral carotid bifurcation disease, but only 16% of these were considered surgically remediable; five of these patients eventually required carotid endarterectomy (CEA). Nine of the 18 patients with asymptomatic Hollenhorst plaques were further evaluated with serial ocular fundus photography: the plaque persisted in all nine patients—in four for more than 6 months and in five for more than 1 year. No patient had transient or fixed retinal or cerebral symptoms. Twenty-six patients with amaurosis fugax showed a 70% incidence of significant bifurcation disease and three had significant intracranial disease; 50% eventually required CEA. Twelve patients with fixed visual deficits (four patients had homonymous hemianopsia, four had retinal artery occlusions, and four had ischemic retinopathies) demonstrated a 100% incidence of bifurcation disease, but in addition 85% had significant intracranial disease; only one of this group had surgically amenable disease. Amaurosis fugax preceded blindness in two patients. Hollenhorst plaque as an isolated phenomenon appears to be a retinal embolic event of uncertain age, with poor predictive power for further embolic events, and not as highly correlated with significant or surgically amenable carotid bifurcation disease.

The clinical significance of the asymptomatic Hollenhorst plaque.

Sixty consecutive patients with visual complaints as the primary symptom of cerebrovascular insufficiency were evaluated with complete cerebral angiography (CCA). Eighteen patients referred for evaluation of asymptomatic Hollenhorst plaques had a 50% incidence of ipsilateral carotid bifurcation disease, but only 16% of these were considered surgically remediable; five of these patients eventually required carotid endarterectomy (CEA). Nine of the 18 patients with asymptomatic Hollenhorst plaques were further evaluated with serial ocular fundus photography: the plaque persisted in all nine patients--in four for more than 6 months and in five for more than 1 year. No patient had transient or fixed retinal or cerebral symptoms. Twenty-six patients with amaurosis fugax showed a 70% incidence of significant bifurcation disease and three had significant intracranial disease; 50% eventually required CEA. Twelve patients with fixed visual deficits (four patients had homonymous hemianopsia, four had retinal artery occlusions, and four had ischemic retinopathies) demonstrated a 100% incidence of bifurcation disease, but in addition 85% had significant intracranial disease; only one of this group had surgically amenable disease. Amaurosis fugax preceded blindness in two patients. Hollenhorst plaque as an isolated phenomenon appears to be a retinal embolic event of uncertain age, with poor predictive power for further embolic events, and not as highly correlated with significant or surgically amenabe carotid bifurcation disease.

Disc Vascularity in Downʼs Syndrome

Ocular fundus photographs of 100 eyes were obtained from an institutionalized population of patients with Down's Syndrome (66 males, 34 females). The vascularity of the optic nerve head was assessed in each photograph by counting the number of arterioles, venules, and fine vessels crossing the disc margin. The results of this analysis were compared to similar data obtained from 100 ocular fundus photographs of normal patients and show that there are more large vessels crossing the disc margin in those with Down's Syndrome.

Ocular fundus photography of workers exposed to carbon disulfide: A comparative epidemiological study between Japan and Finland: by K. Sugimoto, S. Goto, H. Taniguchi, T. Baba, Ch. Raitta, M. Tolonen, and S. Hernberg. Int Arch Occup Environ Hlth 39:97–101, 1977

Ocular fundus photography of workers exposed to carbon disulfide: A comparative epidemiological study between Japan and Finland: by K. Sugimoto, S. Goto, H. Taniguchi, T. Baba, Ch. Raitta, M. Tolonen, and S. Hernberg. Int Arch Occup Environ Hlth 39:97–101, 1977

Ocular Fundus Photography

This chapter is a review of fundus photography techniques, with particular emphasis on the important parameters of producing high quality fundus photographs. The role of fundus photography has extended beyond that of a documentary service to one with specific diagnostic value. Thus, ocular fundus photography relates directly to patient care and is an essential part of the sophisticated armamentarium of any clinical ophthalmological unit.

Penetration of retinal and vitreous opacities in diabetic retinopathy. Use of infrared fundus photography.

Infrared radiation has the capability of penetrating some types of opacities so that photographs can be made with infrared sensitive film of structures that cannot be seen by the human visual system. This technique was applied to ocular fundus photography in patients with various manifestations of diabetic retinopathy including retinal hemorrhages and exudates, neovascular tufts, marked proliferative tissue, and vitreous hemorrhage. In all such cases the infrared photographs depicted the optic disc, retinal vessels, and choroidal vasculature underlying the opacities when these structures could not be seen through the intervening opacities in routine photographs or on clinical examination. This technique has potential for revealing fundus abnormalities hidden from ordinary view by retinal or vitreous opacities.

Ocular Fundus Photography : Suggestions for achieving consistently good pictures and instructions for stereoscopic photography

Ocular Fundus Photography : Suggestions for achieving consistently good pictures and instructions for stereoscopic photography