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At least 973 records · Page 54Linked to original sources
PubMed2000

Ocular fundus abnormalities in children born before 29 weeks of gestation: a population-based study.

PURPOSE: Preterm birth has been found to be associated with increased morbidity of the central nervous and vascular tissues. To investigate the influence of preterm birth on the optic disc and retinal vessels, we examined the ocular fundus in school-aged children born very preterm. METHODS: A prospective, population-based study was performed in 50 very preterm children (median age 7 years, range 5-9 years) with a median gestational age at birth of 27 weeks (range 24-28 weeks) and a median birth weight of 1055 g (range 450-1520 g). The ocular fundus was examined by ophthalmoscopy in 50 children, and the optic nerve and retinal vessel morphology was evaluated by digital image analysis of ocular fundus photographs in 45 of these children. RESULTS: The median optic disc area was significantly smaller (p = 0.0002) in the preterm children compared with a reference group. There was no difference in cup area and, consequently, the rim area was significantly smaller (p = 0.0002) in the preterm children. Children with early signs of brain lesions commonly had a rim area below the median of the reference group. Preterm children also commonly had an abnormal retinal vascular pattern that was independent of a previous history of retinopathy of prematurity. CONCLUSION: Very preterm birth was associated with subnormal optic disc and rim areas and an abnormal vascular pattern. The findings clearly demonstrate the effect of preterm birth on the development of these structures. The long term clinical prognosis of these findings has yet to be determined.

Adolescent↗
PubMed1990

[Retinal vascular occlusions are independent of optic disk size. A morphometric study of 140 patients].

The size of the optic nerve head influences the prevalence of optic disk anomalies and diseases. The authors investigated whether this also holds true for retinal vessel occlusions. The optic disks of 140 patients with central or branch occlusions of the retinal veins and arteries were measured, using photographs of the optic disk and correcting the photographic enlargement by Littmann's method. There were no significant differences in size and shape (Mann-Whitney Test) between the disks thus studied and 457 nonselected optic nerve heads. The incidence of retinal vessel occlusions appears to be unrelated to the shape and size of the optic disk.

Aged↗
PubMedDate not supplied

Optic disk vasculitis associated with chronic active Epstein-Barr virus infection.

PURPOSE: To report two cases of optic disk vasculitis associated with chronic active Epstein-Barr virus infection (CAEBV). METHOD: We examined the eyes of two patients with CAEBV. RESULTS: In the first case, a 6-year-old boy, visual acuity was 20/20 in both eyes. Papillary and peripapillary exudates were observed in the right eye. Fluorescein angiography showed hyperfluorescence of the optic disk and a leakage from the peripapillary retinal vessels in the right eye. Two months later, the exudates increased and preretinal hemorrhages appeared in the right eye. Visual acuity decreased to 20/60. He was treated with systemic administration of corticosteroid, globulin and acyclovir. Visual acuity returned to 20/20, but peripapillary exudates remained in the right eye. In the second case, a 16-year-old girl, visual acuity was 20/20 in both eyes. The right eye showed optic disk swelling and dilated retinal veins. Fluorescein angiography showed hyperfluorescence of the optic disk but no leakage from the retinal vessels. Visual field examination revealed an enlarged blind spot in the right eye in both cases. These ocular manifestations are compatible with those of optic disk vasculitis, which shows swelling of the optic disk and dye leakage on and around the optic disk in fluorescein angiography, with an almost normal visual acuity and an enlargement of the blind spot. CONCLUSION: Persistent Epstein-Barr virus infection may cause optic disk vasculitis.

Acyclovir↗
PubMed1990

Fluorescein angiography of the newborn rat. Implications in oxygen-induced retinopathy.

The current technique was developed to characterize the morphologic changes in the retinas of oxygen-reared rats, as an animal model of retinopathy of prematurity. Past studies have used ink perfusion to observe the retinal vasculature, but this method is static and requires the sacrifice of the subject. Fluorescein angiography, however, is dynamic and relatively noninvasive, and allows the survival of the animal for further study. The fundus camera cannot be used because the source of light that is focused in an annulus is too large for the pupil size of a young (approximately 14-day-old) rat. To overcome this, a Nikon inverted microscope (Diaphot-TMD) was used. Using the proper exciting and barrier filters for fluorescene, a photographic sequence was made by rapidly focusing to the plane of the retinal vessels. To our knowledge, similar photographs have not been previously published. This technique was used in newborn pigmented ratlings that were 1) exposed to 80% oxygen for the first 14 days of life; 2) exposed to 80% oxygen for the first 21 days of life; or 3) exposed for the first 14 days followed by 7 days in room air. Age-matched controls were raised simultaneously in room air and evaluated with the same technique. Differences were observed between treatments in the amount of retinal capillary loss, and in the tortuosity and diameter of the major retinal vessels. The hyaloid system also varied between treatment groups. Oxygen-exposed rats showed a persistence of the hyaloid vessels that was particularly prominent in the group returned to room air before analysis. Comparisons are made to past results obtained with other histologic techniques.

Animals↗
PubMed1997

Fluorescent dots in fluorescein angiography and fluorescein leukocyte angiography using a scanning laser ophthalmoscope in humans.

PURPOSE: The purpose of the study is to disclose the nature of fluorescent dots and segments traditionally observed with fluorescein angiography (FA) using a scanning laser ophthalmoscope (SLO 101; Rodenstock, München, Germany). The authors developed a new method, called fluorescein leukocyte angiography (FLA), to display directly the movement of leukocytes in human retinal vessels. METHODS: Fluorescein angiography was performed on two normal volunteers using a scanning laser ophthalmoscope and fluorescent dots and segments were observed. Fluorescein leukocyte angiography, using an injection of fluorescent buffy coat layer from which the fluorescent plasma and nonfluorescent erythrocytes have been removed externally, was performed on seven normal volunteers. Injection fluid smears were examined through a fluorescent microscope. Peripheral blood smears taken during midphase of FA and FLA also were examined. In addition, 15 early-phase FAs of central serous chorioretinitis (CSC) were studied retrospectively. RESULTS: In the FAs of normal volunteers, fluorescent dots were detected only in perimacular capillaries at early phase. Eight of the 15 CSC FAs examined showed both fluorescent dots and segments. In the FLAs, fluorescent dots were detected in whole retinal vessels for more than 30 minutes. Fluorescent segments were observed in FA but not in FLA. Injected fluid smears from one FLA showed fluorescent leukocytes and small platelets. However, in peripheral blood smears of the FLA, leukocytes and platelets were more visible and exhibited higher contrast than those of an FA due to background plasma fluorescence. The mean velocity of 21 flowing leukocytes in perifoveal capillaries was 1.37 +/- 0.35 mm/second in 2 FAs and that of 89 flowing leukocytes was 1.41 +/- 0.29 mm/second in 7 FLAs. CONCLUSIONS: The authors' observations suggest that fluorescent dots in scanning laser ophthalmoscope imaging are fluorescein-stained leukocytes, whereas fluorescent segments are the hyperfluorescent plasma that is located between rouleaux formations of erythrocytes. The velocity of the fluorescent dots could be measured in the perimacular capillaries by either FA or FLA; however, only FLA can display the flow of fluorescent leukocytes in large vessels.

Adult↗
PubMed1979

Late complications of retrolental fibroplasia.

A modified classification of cicatricial RLF has been presented. Particular emphasis is placed on myopia, one of the hallmarks of grade i cicatricial RLF. Whether or not this is axial myopia is still open to question, but since the more myopic eye was usually longer by ultrasonic measurement than the less myopic eye, actual enlargement of the eye must play some role. Other features noted in grade I RLF were retinal pigmentation, vitreous membranes, and equatorial retinal folds. In grade II the most significant finding was dragging of the retina. It was noted that in all cases of dragging of the retina there were also peripheral retinal changes. Even more important, however, was the fact that peripheral retinal changes are often present when there are no changes in the posterior pole. Neovascularization, elevated retinal vessels, lattice degeneration, and retinal breaks were other features of grade II retinopathy. Significant was the fact that the incidence of lattice in patients with cicatricial RLF (15%) was more than twice that of the normal population. Grade III RLF was characterized by falciform retinal folds, and grade IV, by retinal detachment. Thirty-nine retinal detachments were rhegmatogenous and usually had temporal retinal breaks. Retinal detachments of a tractional exudative variety (14 eyes) tended to occur earlier in life than the rhegmatogenous variety. In infants, they were preceded by increased tortuosity of the vessels in the posterior pole and, sometimes, accumulation of exudation, both ominous prognostic signs.

Adolescent↗
PubMed2003

Flicker light-induced vasodilatation in the human retina: effect of lactate and changes in mean arterial pressure.

PURPOSE: Diffuse luminance flicker light increases retinal and optic nerve head blood flow in animals and humans, but the exact mechanisms that mediate increased flow have yet to be identified. In the current study, the effect of increased plasma lactate levels on flicker-induced vasodilatation in the retina was investigated in three independent studies in healthy humans. METHODS: In the first study, plasma lactate concentrations were increased by bicycle exercise in 12 volunteers, and the change in retinal vessel diameter to 8-Hz square-wave flicker stimulation was measured with the Zeiss Retinal Vessel Analyzer (Carl Zeiss Meditec, Oberkochen, Germany). In a different study, sodium lactate was administered intravenously, and flicker responses were measured in 12 subjects. As a control experiment accounting for pressure increases induced by exercise, the effect of elevated ocular perfusion pressure on the flicker response was investigated during tyramine infusion (n = 12). RESULTS: The increase in plasma lactate concentration during intravenous infusion from 1.3 +/- 0.4 to 6.3 mmol/L and during dynamic exercise from 1.2 +/- 0.3 to 9.4 mmol/L decreased flicker responses in retinal arteries from 5.3% +/- 0.9% to 1.7% +/- 0.6% (P < 0.001) and from 3.6% +/- 0.6% to 2.0% +/- 0.8% (P = 0.03), respectively. In contrast, an increase of mean blood pressure from 81 +/- 3 to 92 +/- 3 mm Hg after tyramine infusion had no significant effect on flicker-induced vasodilatation in retinal arteries and veins. CONCLUSIONS: The signaling between neuronal activity and flow response in the human retina is sensitive to changes in blood lactate levels, whereas changes in systemic blood pressure have no major effect. Whether an increased cytosolic redox impairment contributes to flicker-induced vasodilatation has yet to be clarified.

Blood Pressure↗
PubMed2006

Determination of retinal blood vessel diameters and arteriovenous ratios in systemic hypertension: comparison of different calculation formulae.

BACKGROUND: Generalized arteriolar narrowing is one of the retinal changes influenced by systemic hypertension. The ratio of retinal arteriolar to venular diameters is often used as a marker of generalized arteriolar narrowing. There are several ways to determine the retinal arteriovenous ratio (A/V ratio). However, no comparison of retinal vascular measurements and A/V ratios determined by different formulae has been presented. METHODS: Eighty-seven men participating in the Tampere Ambulatory Hypertension Study returned for a 10-year follow-up examination in which fundus photographs were taken of both eyes. The diameters of retinal arterioles and venules were measured 1 and 2 disc diameters from the optic disc edge. The A/V ratio was determined using mean arteriole and venule width, the sum of widths of arterioles and venules, the sum of squares of widths of arterioles and venules, the central retinal artery equivalent (CRAE) and the central retinal venous equivalent (CRVE). The repeatability of measurements and A/V ratios was determined. Comparison was made between A/V ratios determined by different calculation formulas. RESULTS: In general, determination of A/V ratios yielded lower deviation than that of diameters of arterioles and venules separately. Calculation of A/V ratios using different formulas gave different ratio levels. According to linear regression analysis, the A/V ratio calculated using the sum of squares of widths of arterioles and venules correlated best with CRAE/CRVE (R(2) 0.92) and A/V ratios calculated using the mean arteriole and venule widths or the sum of widths of arterioles and venules resulted in clearly lower associations (R(2) 0.38-0.40 and R(2) 0.41-0.48, respectively). Of all A/V ratios, CRAE/CRVE had the best repeatability. No statistically significant differences were found between measurements from right and left eyes. CONCLUSIONS: The high repeatability of CRAE/CRVE and sum of squares of widths of arterioles/sum of squares of widths of venules, as well as the good association of the two formulae, favor the use of these in evaluation of retinal vascular changes in systemic diseases. Our results also showed that if only one eye can be examined, it seems to suffice if fundus vascular alterations associated with systemic hypertension are evaluated.

Adult↗
PubMed1989

Responses of the retinal circulation to systemic autonomic stimulation in diabetes mellitus.

The retinal vessel calibre responses to systemic sympathetic stimulation, were studied in 22 randomly selected diabetic patients (mean age +/- SEM: 54.7 +/- 2.59 years, range 25-73; 13 IDDM, 9 NIDDM; 4 females), using sustained isometric muscle contraction as the stimulus. At a different session the integrity of the autonomic nerve function in these diabetic patients was assessed using 3 standard tests of autonomic nerve function, based on cardiovascular reflexes. Diabetic patients with an intact autonomic nervous system: Group 1, (n = 11, mean age: 54.9 +/- 4.55 years, 7 IDDM 4 NIDDM) showed a mean arteriolar constriction of 9.2% (SEM 2.89, p less than 0.01) and a mean venule constriction of 5.1% (SEM 1.73, p less than 0.02), for a mean rise in diastolic blood pressure of 23.7 mmHg (SEM 2.19 range: 13-33). There were no significant mean retinal vessel responses however, in diabetics with autonomic dysfunction (Group 2): mean arteriolar constriction of 1.2% (SEM 1.38 p greater than 0.05) and venule constriction of 2.1% (SEM 1.38, p greater than 0.05); for a mean rise in diastolic blood pressure of 19.8 mmHg (SEM 4.49, range: 2-50). There was no correlation between the rise in diastolic blood pressure and the retinal arteriolar constriction in the 2 groups (Group 1:r = 0.45, p greater than 0.01 and Group 2: r = 0.56, p greater than 0.05). Duration, type and control of diabetes were not significantly different between the 2 groups. The severity of retinopathy was slightly worse in Group 2 compared to Group 1. These results point to an association between autonomic neuropathy and failure of regulation of retinal blood flow.

Adult↗
PubMed1987

Comparison of optic disc features in low-tension and typical open-angle glaucoma.

This study was undertaken to identify features of optic nerve head architecture that might explain, in part, why ganglion cell loss occurs in patients with low-tension glaucoma. We compared retrospectively the disc photographs of 25 patients with low-tension glaucoma with those of 26 control patients with typical open-angle glaucoma. No differences were observed in any of the following features: pore length, shape, or size variation; cup/disc and disc/arteriole ratio; clock positions of total rim loss; central retinal vessel entry site; rim pallor; number of rim-crossing vessels; and presence or absence of peripapillary nerve fiber layer hemorrhages, optic pits, and central retinal vessel canals. An hour-glass appearance of connective tissue bundles within the scleral lamina cribrosa, however, was present statistically less often in patients with low-tension glaucoma (p = 0.007). We speculate that the microscopic arrangement of fiber bundles within the lamina cribrosa may play an etiologic role in the pathogenesis of low-tension glaucoma.

Adult↗
PubMedDate not supplied

Evaluation of the circulation in the retina, peripapillary choroid and optic disk in normal-tension glaucoma.

Computerized image analysis, including fluorescein angiography, was used to evaluate the retinal, choroidal and optic disk blood flow in 16 patients with normal-tension glaucoma (NTG) and to correlate this measurement with visual fields, retinal vessel width, optic disk pallor and blood pressure (BP). The angle of the ascending slope of the fluorescein dye curve was measured as an index of blood flow from the densitometric and time curves of the fluorescein angiograms in the optic disk, peripapillary choroid, retinal artery and vein for each quadrant. While the ascending slope as well as the retinal vessel width were most reduced in the inferior and nasal regions, the mean threshold was lowest in the superior and nasal quadrants. There were positive significant correlations between artery width and threshold value, between angles of slopes and pallor. In addition, systolic BP had a negative correlation with pallor, and diastolic BP had a positive one with slope in the choroid. These results indicated the probable association of a decrease in retinal, choroidal and optic disk blood flow in the inferior and nasal quadrants as well as vessel width in the inferior nasal quadrant with visual field loss in the superior quadrant, and also demonstrated an increasing blood flow for enlargement of pallor. A decrease in BP was found to be related to reduced blood flow in choroid and optic disk impairment.

Blood Circulation↗
PubMed1996

[The new laser Doppler velocimetry for the measurement of retinal circulation and its clinical application].

We developed a new laser Doppler instrument to measure retinal blood flow. This instrument is equipped with an eye tracking system, which maintains the laser beam on the retinal vessel, thus enabling the measurement of patients with poor visual acuity and poor fixation. In diabetic patients even those without retinopathy, the retinal blood flow decreased compared to the control subjects. This was mainly the result of decreased retinal blood speed and no significant change in the arterial diameter. In diabetic patients requiring panretinal photocoagulation, we studied the regional changes in retinal blood flow following superior or inferior half fundus argon laser treatment, which produced a significant retinal blood flow decrease only in the treated area. We also studied the retinal circulatory changes in retinal branch vessel occlusion. In retinal branch view occlusion, the blood flow in arteries supplying the affected lesion showed 80-90% decrease compared to the arteries supplying the unaffected region. In retinal branch artery occlusion, the retinal blood flow in occluded arteries showed 40-50% decrease compared to the non-occluded arteries. In one patient with retinal branch vein occlusion in whom we measured the retinal blood flow over 18 months, the blood flow increased with the development of collateral vessels. The results showed that retinal circulatory abnormalities can be also evaluated quantitatively during the course of retinal vascular occlusive disease by our newly developed laser Doppler instrument, which proved that this instrument is a clinically very useful tool.

Adult↗
PubMed1996

In vivo quantification of leukocyte behavior in the retina during endotoxin-induced uveitis.

PURPOSE: The interaction between leukocytes and vascular endothelial cells plays an important role in various inflammatory disorders. This study evaluated leukocyte behavior in the retina during endotoxin-induced uveitis (EIU) in vivo. METHODS: EIU was induced in female Lewis rats by footpad injection of lipopolysaccharide (LPS). The time-course changes of retinal leukocyte behavior were followed at 1.5, 3, 4.5, 6, 12, 24, 48, 72, and 120 hours after LPS treatment using acridine orange digital fluorography, consisting of high-resolution images from a scanning laser ophthalmoscope and a fluorescent nuclear dye of acridine orange. RESULTS: Major retinal vessels were significantly dilated (P < 0.05) at 4.5 hours after LPS injection. The vasodilation, marked in veins, became maximum at 24 hours and subsided at 72 hours. Leukocytes were observed rolling along the walls of major veins at 4.5 hours. The number of rolling leukocytes gradually increased and reached a peak level of 33.8 +/- 3.4 cells/minute per major vein at 12 hours. Leukocyte rolling was still observed at 72 hours. No rolling of leukocytes was observed along the arterial walls throughout any experiments. The velocities of rolling leukocytes were determined at 6, 12, 24, and 48 hours. The leukocyte rolling velocity at 6 hours was significantly slower (33.3 +/- 2.8 microns/second, P < 0.05) than at the other three times (average, 46.6 microns/second). Cellular infiltration into the vitreous cavity was detected at 24 hours and reached its maximum at 48 hours. CONCLUSIONS: This study demonstrates that it is possible to evaluate EIU by investigating retinal leukocyte behavior and that vasodilation of major retinal vessels and leukocyte-endothelial interactions precede inflammatory cell emigration into the vitreous. This method may be useful to quantify the severity of inflammation in EIU.

Acridine Orange↗
PubMed1986

Aldose reductase localization in dog retinal mural cells.

The selective degeneration of retinal mural cells, a hallmark of early human diabetic retinopathy, has also been reported to occur in both diabetic and galactose-fed dogs. By employing antibodies raised against purified dog lens aldose reductase the presence of aldose reductase can be immunohistochemically demonstrated in the cytoplasm of mural cells but not endothelial cells of dog retinal vessels isolated by trypsin digestion. This immunohistochemical staining is similar to that observed with isolated human retinal vessels.

Aldehyde Reductase↗
PubMed2004

Reduction of retinal blood flow in high myopia.

PURPOSE: To investigate changes in retinal vessel diameter and blood velocity in high myopia using laser Doppler velocimetry. METHODS: Thirty-nine subjects (39 eyes) were enrolled in the study. The subjects were divided into three groups according to their refractive status; 15 eyes (15 patients) with emmetropia (within +/-3.0 diopters), 14 eyes (14 patients) with mild myopia (between -3.0 and -8.0 diopters), and 10 eyes (10 patients) with high myopia (>-8.0 diopters). Patient age was matched between groups. Blood velocity and vessel diameter of the upper or lower temporal retinal artery were measured using laser Doppler velocimetry with an eye-tracking system, and measurements were compared between groups. RESULTS: The average retinal blood flow and vessel diameter in highly myopic eyes were significantly decreased compared with emmetropic eyes or mild myopic eyes (Mann-Whitney U test, p<0.05). Also, there was significant difference regarding retinal blood flow and vessel diameter between eyes with mild myopia and the other groups. In addition, there was no significant difference in blood velocity between the three groups. CONCLUSIONS: Retinal blood flow was decreased in high myopia, mainly due to the narrowing of the retinal vessel diameter. Impaired retinal blood flow might have a role in the development of chorioretinal atrophy in high myopia.

Adult↗
PubMed2006

Retinal function in infants with optic nerve hypoplasia: electroretinograms to large patterns and photopic flash.

AIMS: Optic nerve hypoplasia (ONH), which is defined as a congenital deficiency of retinal ganglion cells, may also involve more distal layers of the retina. We investigated electrophysiological function of the retina in ONH using electroretinograms (ERGs). METHODS: ERGs were recorded from 48 subjects (3.5-35 months) with unilateral or bilateral ONH. Pattern reversal (4 degrees checks) was presented under chloral hydrate sedation, using an optical system to correct a cycloplegic refraction. A photopic flash stimulus was also used. Fundus photographs were used to measure the disk diameter/disk macula ratio (DD/DM), and to document other clinical signs. Eyes were classified as moderate (0.15-0.3) or severe (<0.15) ONH, and those with DD/DM greater than 0.3 were used as reference eyes. RESULTS: Pattern ERG recording was completed in 89 eyes and was detectable in 80% of eyes with ONH (61/76 tested) and in all 13 reference eyes. Photopic flash ERGs were of good quality in all eyes. The severity of ONH correlates with the amplitude of the photopic flash b-waves and with the amplitude of the N95 component of the pattern ERG (P<0.01). However, the ERGs to large patterns were well preserved (>3.5 microV) in 10 of 35 eyes with severe ONH. Tortuous retinal vessels in eyes with either moderate or severe ONH were associated with smaller amplitude photopic b-waves and markedly diminished or undetectable pattern ERGs. CONCLUSIONS: This study supports the hypothesis that retinal dysfunction distal to the ganglion cells is common in ONH, but is not predictable on the basis of ONH severity alone. Additionally, tortuous retinal vessels in ONH may be a sign associated with retinal dysfunction.

Child, Preschool↗
PubMed1989

[The retinal nerve fiber layer in normal and glaucomatous eyes. II. Correlations].

The retinal nerve fiber layer is different in normal and glaucomatous eyes. We correlated semi-quantitative data of the retinal nerve fiber layer of 398 eyes with chronic primary open-angle glaucoma and of 234 normal eyes with the intra- and parapapillary morphometric signs and with the perimetric indices. The three parameters "sequence of the fundus sectors concerning the best visibility of the retinal nerve fiber bundles", "visibility of the nerve fiber bundles", and "localized defects" were significantly (p less than 0.001) correlated to 1) area of the neuroretinal rim as a whole and in four different optic disc sectors, 2) neuroretinal rim width determined every 30 degrees, 3) optic cup area, diameters and form, 4) horizontal and vertical cup/disc ratios and the quotient of the horizontal to vertical cup/disc ratio, 5) area and width of zone "Alpha", zone "Beta", and the total parapapillary chorio-retinal atrophy, 6) diameter of the retinal vessels, 7) grade of a "tesselated fundus", and 8) the visual field loss. If only the inferior temporal and the superior temporal sectors were considered, the retinal nerve fiber bundles were less visible in that sector with the largest notch in the neuroretinal rim, the smaller neuroretinal rim area and width, the thinner retinal vessels, and the larger zone "Alpha", zone "Beta", and total parapapillary chorio-retinal atrophy. The glaucomatous changes in the retinal nerve fiber layer are correlated in time and location with the intra- and parapapillary and the perimetric alterations. Evaluation of the retinal nerve fiber layer is a useful method to detect a glaucomatous optic nerve damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗