Biomedical subjects
Publications and source records attributed to S Y Cohen.
Acute blurred vision is a usual clinical setting which could be related to many different etiologies. The ophthalmologist has to precise the symptomatology to differentiate long or short visual acuity loss, troubles of accommodation, metamorphopsia or central scotomas. Then a complete ophthalmologic examination will try to localise the causative lesion in the cornea, the lens, the chorio-retina or in the intraocular media.
PURPOSE: The fluorescein angiographic features of angioid streaks are variable, and angioid streaks and their main complication, choroidal neovascularization, can sometimes be difficult to visualize in the presence of diffuse pigment migration, diffuse atrophy of the retinal pigment epithelium, or hemorrhage. The objective of the present investigation was to define the indocyanine green angiographic features of angioid streaks and to compare them with findings on fluorescein angiography. METHODS: For this prospective study, we recruited 22 consecutive patients, 21 of whom had angioid streaks and one who had typical peau d'orange appearance of the fundus. Complete ophthalmologic examination, fluorescein angiography, and indocyanine green videoangiography by the means of scanning laser ophthalmoscope were performed on all patients. RESULTS: In 21 patients with angioid streaks and in one patient with peau d'orange appearance of the fundus, indocyanine green videoangiography showed angioid streaks in the form of hyperfluorescent lines with numerous associated hyperfluorescent foci. The angioid streaks were more clearly visualized and were seen to be more numerous and larger by indocyanine green videoangiography than with red-free images or fluorescein angiography. Choroidal neovascularization was suspected in six eyes but could be precisely localized by fluorescein angiography in only three eyes. Indocyanine green angiography allowed precise localization of choroidal neovascularization in all six of these eyes. CONCLUSIONS: These findings indicate that indocyanine green videoangiography provides different information than fluorescein angiography in the evaluation of angioid streaks and can more precisely localize their neovascular complications.
Perifoveal laser photocoagulation has been proposed for the treatment of subfoveal neovascular membranes in age-related macular degeneration. We evaluated residual function in seven eyes of six treated patients by means of transient focal visual potentials evoked with a scanning laser ophthalmoscope. The site of the preferred retinal locus was determined. The modulation of the helium-neon laser beam generated three tests (a homogeneous 6 x 6 degrees square--offset and onset--and two alternating pattern checkerboards 6 x 6 degrees and 2.5 x 2.5 degrees 60', 2 Hz) projected onto the preferred retinal locus. The focal visual evoked potentials were recorded. One eye had an unstable fixation with no discernible focal visual evoked potentials. The other six eyes had a stable fixation located in the superior retina, temporally for the right eyes and nasally for the left eyes. The homogeneous 6 x 6 degrees square evoked discernible responses in all six patients. The two checkerboards evoked discernible responses in five of six patients. These results were compared with those recorded in four controls in whom the three tests were projected onto the same retinal areas as in the patients. Evoked responses were more often recorded in the preferred retinal locus of the treated patients with age-related macular degeneration than in the corresponding retinal areas of the controls. The scanning laser ophthalmoscope allowed us to control the site of stimulation in the patients' and controls' retinas. These preliminary results suggest that there may be a functional plasticity of the visual system after therapeutic laser-induced central scotoma.
Basal laminar drusen (BLD) are small round yellow drusen that are more easily visualised angiographically than biomicroscopically, with a 'stars in the sky' pattern. Patients with BLD are predisposed to macular vitelliform detachment. Little is known about the course of the disease, but the prognosis for retention of useful central vision for patients with BLD is thought to be better than for patients with typical drusen. A retrospective analysis of clinical and angiographic charts of 19 patients with BLD combined with a vitelliform macular detachment was performed to precisely describe their course. In addition, nine patients were re-examined to allow an analysis of their visual function--that is, central visual field, contrast sensitivity, and colour vision. Eyes without choroidal new vessels retained a fair visual acuity (mean final visual acuity 0.5; follow up 4 to 69 months, mean 24 months). In 11 of these eyes visual function assessment disclosed a reduction of contrast sensitivity in high and medium spatial frequencies in nine eyes (81%), a blue-yellow dyschromatopsia in nine eyes (81%), and a mild reduction of foveal threshold in seven eyes (63%). Choroidal neovascularisation (CNV) was observed in 12 eyes (31%) with a poor final outcome (mean final visual acuity 0.1). Two thirds of cases of CNV were observed at the time of presentation; thus this finding may be a bias of a referring centre. However, the high prevalence of CNV suggests the need for a close follow up of patients with BLD.
Basic fibroblast growth factor (bFGF), a soluble mitogen, has been isolated and purified from various organs, including the retina. In vivo angiogenic activity of bFGF has been demonstrated with several assays. An experimental model of choroidal neovascularization was developed in the mini pig by perfusion of recombinant human bFGF through an osmotic minipump. Endogenous bFGF and bFGF receptors were localized in the normal pig retina by immunohistochemistry and autoradiography after binding. The perfusion of exogenous bFGF induced well-organized new vessels along the last 3 mm of the catheter in the suprachoroidal space. This neovascularization did not penetrate the normal Bruch's membrane. Vascular cells (identified by von Willebrand factor antibody staining) increased in number and in surface from the proximal part to the end of the intraocular catheter in all bFGF perfused eyes. In eyes perfused with phosphate buffered saline (controls), but not in the bFGF perfused eyes, an inflammatory response occurred (identified by a macrophage specific antibody). These results demonstrate that choroidal angiogenesis can be achieved without an inflammatory response by perfusing an excess of bFGF in the suprachoroidal space.
The eye is a perceptive system with extremely complex physiology, although its optical properties can be assimilated to those of spherical diopters. Various approximations make it possible to reduce the eyeball to a single convex diopter. With a normal eye the image of an object situated ad infinitum focuses on the retina. The normal eye is called emmetropic. Otherwise, the eye is called ametropic. Several types of ametropy exist. When the image focuses in front of the retina the eye is said to be myopic. When the image focuses behind the retina the eye is called hypermetropic (or hyperopic). When the image of an object differs according to various focusing axes, the eye is said to be astigmatic.
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BACKGROUND: Congenital hypertrophy of the retinal pigment epithelium (CHRPE) is a well-defined clinical entity with usually well-delineated, pigmented oval or round lesion with smooth or scalloped margins. Occasional retinal vascular changes have been reported previously. PURPOSE AND METHOD: To assess the prevalence of these changes, the authors performed a retrospective analysis of 12 patients with CHRPE, for whom fluorescein angiography allowed visualization of the entire lesion and of the retinal vascular capillary bed. RESULTS: Retinal vascular changes were found in 11 (91%) of these 12 patients. The changes consisted of capillary rarefaction in all 11 patients, with areas of capillary nonperfusion exceeding 1 disc diameter (DD) in three patients (25%), micro-aneurysmal capillary dilatations in three (25%), and chorioretinal anastomosis in one. CONCLUSION: These results suggest that the above changes could constitute clinical and angiographic characteristics of CHRPE and allow easy corroboration of its diagnosis, thus avoiding the need for further clinical investigations.
Argyrosis is a cutaneous discoloration caused by silver. Ocular involvement, including conjunctival and corneal discoloration, has been previously reported. To our knowledge, a retinal involvement was never reported and no data is available about fluorescein angiography patterns of patients with argyrosis. Fluorescein angiography was performed in six consecutive patients with iatrogenic systemic argyrosis. A dark choroid was observed in each case. Red light monochromatic pictures disclosed a leopard spot pattern on the fundus, which was more clearly revealed in one patient by infrared light pictures. These findings suggest that the silver deposit in Bruch's membrane may be responsible for the obscuration of choroidal fluorescence during dye transit and for the visualization of choriocapillary units in pictures using long-wavelength light. The dark choroid is not only present in central retinal dystrophies, but may be observed in other conditions, such as systemic argyrosis.
The number of axons in the optic nerve decreases with age and this degeneration is greater in patients suffering from Alzheimer's disease. Alterations in the role of neurotrophic factors could lead to this degeneration. Acidic fibroblast growth factor (aFGF)-like immunoreactivity was examined by indirect immunofluorescence on cryostat sections incubated with a rabbit polyclonal antiserum specific for aFGF. Staining was observed by photonic microscopy on optic nerves of Wistar rats (1- to 25-month-old), bovine animals (0.5- to 7-year-old) and normal human adults (24-, 34-, 54- and 84-year-old). In the three species studied, the results show that (1) glial cells were stained in the nuclear region and (2) aFGF-like immuno-reactivity was present over a large age span in adult subjects. Endogenous aFGF may have trophic effects on retinal ganglion cells and their axons throughout the adult life span.
Chorioretinal folds may be observed in many choroidal or retinal diseases. In age-related macular degeneration, they are usually associated with retraction of a neovascular membrane and a typically radial pattern of the folds can be seen. In this disease, pigment epithelium folds were recently described. Their clinical and angiographical characteristics are different from chorioretinal folds and the two diseases should not be confused. A 74-old patient presented, in the left eye, with sub foveal new vessels situated at the center of a pigment epithelial detachment (PED). Radial chorioretinal folds surrounded the PED, as frequently observed during follow-up in subretinal neovascular membranes. Nevertheless, right eye fundus examination revealed roughly horizontal, regular and parallel chorioretinal folds. Ultrasonography demonstrated characteristics of idiopathic chorioretinal folds: flattening and thickening of the posterior sclera and choroid. No sign of posterior scleritis was found. These ultrasonographic elements were observed in the left eye away from the central neovascular membrane. The chorioretinal folds therefore seemed to be idiopathic, in a hyperopic patient. The shape of the folds was modified in one eye by a subfoveal neovascular membrane. Chorioretinal folds may occur in different retinal diseases. The associations with many different aetiologies with modification of the shape of the folds, as described in this clinical case, should be emphasized.
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Acidic fibroblast growth factor (aFGF)-like immunoreactivity was examined in the optic nerves of 1- to 25-month-old Wistar rats, 0.5- to 7-year-old bovine animals and normal human adults (24 and 35 years old), using cryostat sections incubated with a rabbit polyclonal antibody specific for aFGF. The immunoreactivity was associated with glial cells, and was localized predominantly in the nucleus. The presence of endogenous aFGF in the optic nerve of adult subjects and 'old' rats suggests that aFGF could play a role in the survival of retinal ganglion cells and their axons during aging.
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Three patients with retinopathy associated with acute pancreatitis were observed. Each of them had a long history of alcohol abuse. The first patient was asymptomatic. Second one developed moderate visual loss in one eye (visual acuity 20/40), with a fascicular defect on Goldmann visual field registration. Third patient complained with bilateral and severe visual loss, with a large central scotoma. Cotton-wool patches and hemorrhages were present in the mild types of retinopathy. These cases had a good prognosis. An ischemic edema of posterior pole was associated in severe type of retinopathy. In this case, fluorescein angiography showed occluded macular retinal arterioles. Visual prognosis was poor. Pathogenesis of the lesions is still discussed. The main hypothesis are fat emboli or activated complement-induced granulocyte embolus formation. Efficacity of corticosteroids is not known.
Rothmund's syndrome was observed in a 9 year old boy. Parental consanguinity was present, but no siblings were affected. He presented with rapidly progressive bilateral cataracts. Visual recuperation was excellent after "in the bag" phakoemulsification and intercapsular implantation. There were no other ocular anomalies. Extensive erythematous skin changes appeared when the boy was 3 months old and, at the time of presentation, he had poïkiloderma predominantly in those areas exposed to light (face and hands). There were no associated anomalies of the nails or hair, no endocrine disorder nor other malformations. A brief review of this syndrome is presented and treatment of these cataracts discussed.