Assessment of ocular perfusion after carotid endarterectomy with color-flow duplex scanning. (1/430)

PURPOSE: The purpose of this study was to assess the effect of carotid endarterectomy (CEA) on ocular perfusion with the measurement of the ophthalmic artery (OA) and the central retinal artery (CRA) flow velocities with color-flow ocular duplex scanning (ODS). Ocular hemodynamics also were examined in a subset of patients with visual symptoms in an attempt to characterize the origin of the ocular symptoms and their response to surgery. METHODS: Twenty-five patients with internal carotid artery stenoses (>/=70%) underwent 29 CEAs. All the patients underwent ODS for the measurement of the peak systolic velocity (PSV) in the OA and the CRA of the ipsilateral eye before and after CEA. The preoperative and postoperative flow velocities were compared in all the patients and in the patients with and without visual symptoms. RESULTS: The preoperative PSV in the OA was 21.6 +/- 2.2 cm/s and in the CRA was 7.7 +/- 0.7 cm/s. These values were reduced as compared with normative values (OA, 37.8 cm/s; CRA, 10.7 cm/s). After CEA, the PSV increased significantly in both vessels (postoperative OA, 38.6 +/- 2.5 cm/s, P <.0001; postoperative CRA, 12.1 +/- 0.9 cm/s, P =.0008). Fifteen of the 29 CEAs were performed for visual symptoms. The patients with ocular symptoms had significantly lower preoperative PSVs in the CRA as compared with those patients without visual symptoms (CRA with ocular symptoms, 6.5 +/- 0.8 cm/s; CRA with no ocular symptoms, 9.4 +/- 0.9 cm/s; P =.02). The PSV in the OA was not significantly lower in the patients with ocular symptoms. Eight patients (28%) were found to have reversed OA flow before surgery, but only three patients had ocular symptoms. All eight patients had normal antegrade flow in the OA after surgery. CONCLUSION: Severe carotid stenosis may be associated with reduced ocular perfusion, which can be quantitatively evaluated with ODS. Reduced OA and CRA flow velocities are corrected with successful CEA. The patients with ocular symptoms were observed to have significant reductions in CRA flow velocities. Reversed flow in the OA was not a marker for ocular symptoms in this study. ODS can identify global ocular ischemia and may be helpful in the evaluation of patients with atypical visual symptoms or with amaurosis fugax and no evidence of retinal emboli.  (+info)

High frequency of persistent hyperplastic primary vitreous and cataracts in p53-deficient mice. (2/430)

In order to investigate whether the p53 gene product plays a role in normal eye development, age matched p53-deficient mice and wild-type controls were sacrificed from day 2 to day 21 after birth. Eyes were paraffin-embedded and sectioned. Serial sections were taken at the level of the tunica vasculosa lentis and the hyaloid artery. The terminal dUTP nick-end labelling technique (TUNEL) was used to detect the number of cells displaying DNA fragmentation within these structures. Eyes were also prepared for scanning electron microscopy and resin embedded for semi-thin sections. Adult wild-type mice and p53-deficient mice were examined ophthalmoscopically in vivo. Ophthalmoscopical examination of mice completely deficient in p53 revealed them to be normal except for the persistence of the hyaloid vasculature, a structure that normally regresses during eye development. In adult animals there was also a high frequency of cataracts. Using morphological assessment and TUNEL we could show that in normal mice, regression of the primary vitreous, which includes the hyaloid artery, the vasa hyaloidea propria as well as the tunica vasculosa lentis, occurs via apoptotic cell death within 5 - 6 weeks after birth. The number of TUNEL-positive cells within these structures was significantly reduced in the p53-deficient mice in which parts of the hyaloid vasculature persisted and developed into a fibro-vascular retrolental plaque analogous to persistent hyperplastic primary vitreous (PHPV) described in humans. As in humans, PHPV in mice resulted in the development of cataracts. We have identified a role for p53-dependent apoptosis in the regression of the hyaloid vasculature and tunica vasculosa lentis. Our results provide further evidence for the importance of p53 in normal development and provide the first detailed evidence of its role in postnatal development in remodelling the developing eye.  (+info)

Arterial blood flow characteristics in central retinal vein occlusion and effects of panretinal photocoagulation treatment: an investigation by colour Doppler imaging. (3/430)

AIMS: To determine whether an increase in vascular resistance in the central retinal and ophthalmic arterial circulations contributes to the development of central retinal vein occlusion (CRVO), or haemodynamic alterations in central retinal and ophthalmic arteries occur secondary to the vein occlusion as increased intravascular pressure is transferred through the capillary bed to the arterial side and the effect of panretinal photocoagulation treatment on these circulations in ischaemic cases. METHODS: The ophthalmic and central retinal arteries of the affected and non-affected eyes of 20 patients with non-ischaemic CRVO, 13 patients with ischaemic CRVO, and 22 control subjects were investigated by colour Doppler imaging. Panretinal photocoagulation (PRP) treatment was applied to the eyes with ischaemic CRVO. Maximum and minimum blood flow velocities, and resistivity indexes were calculated in the affected and healthy eyes of patients and in the control eyes. RESULTS: Average blood flow velocity in the central retinal and ophthalmic arteries of patients with non-ischaemic CRVO did not differ from their fellow eyes, but a significantly lower average blood flow velocity was found in the ophthalmic and central retinal arteries of the patients with ischaemic CRVO compared with their fellow eyes. Patients with ischaemic CRVO had significantly lower blood flow velocities in their ophthalmic and central retinal arteries than non-ischaemic cases that were further reduced following PRP treatment. CONCLUSION: This study suggests that impaired arterial blood flow observed in patients with CRVO may be partly related to secondary changes in the retrobulbar arterial circulation as a result of enhanced arterial resistance following CRVO. These data also demonstrate that PRP treatment decreases retinal and ophthalmic blood flow velocities in patients with ischaemic CRVO.  (+info)

AIDS related eye disease in Burundi, Africa. (4/430)

AIMS: To determine the prevalence of ocular manifestations in AIDS patients hospitalised in Bujumbura, Burundi, according to their CD4+ lymphocyte count, serological status for CMV and VZV, and general health status. METHODS: Prospective study of 154 consecutive patients who underwent general and ophthalmological examinations, including dilated fundus examination. AIDS was diagnosed on the basis of Bangui criteria and HIV-1 seropositivity. CD4+ lymphocyte counts were determined by the Capcellia method. CMV and VZV antibodies were detected with ELISA methods. RESULTS: The mean age was 37 (SD 9) years and 65% of the patients were male. Active tuberculosis was the most frequent underlying disease (61%). Almost all the patients (99%) were seropositive for CMV and VZV. Among the 115 patients for whom CD4+ lymphocyte counts were available, 86 (75%) had more than 100 cells x 10(6)/l. Ocular involvement comprised 16 cases of microangiopathy, six of opalescence of the anterior chamber, five of retinal perivasculitis, two of zoster ophthalmicus, two of viral retinitis, and one of opalescence of the vitreous. CONCLUSION: In Africa, the prevalence of ocular involvement in HIV infection is far lower than in Europe and the United States, possibly because most African patients die before ocular opportunistic infections occur.  (+info)

Microvasculature of the rat optic nerve head. (5/430)

PURPOSE: To describe the arterial blood supply, capillary bed, and venous drainage of the rat optic nerve head. METHODS: Ocular microvascular castings from 6 Wistar rats were prepared by injection of epoxy resin through the common carotid arteries. After polymerization, tissues were digested with 6 M KOH, and the castings washed, dried, and coated for scanning electron microscopy. RESULTS: Immediately posterior to the globe, the ophthalmic artery trifurcates into the central retinal artery and two posterior ciliary arteries. The central retinal artery directly provides capillaries to the nerve fiber layer and only contributes to capillary beds in the neck of the nerve head. The remainder is supplied by branches of the posterior ciliary arteries that are analogous to the primate circle of Zinn-Haller. Arterioles arising from these branches supply the capillaries of the transitional, or laminar, region of the optic nerve head. These capillaries are continuous with those of the neck and retrobulbar optic nerve head. All optic nerve head capillaries drain into the central retinal vein and veins of the optic nerve sheath. A flat choroidal sinus communicates with the central retinal vein, the choriocapillaris, and with large veins of the optic nerve sheath. CONCLUSIONS: The microvasculature of the rat optic nerve head bears several similarities to that of the primate, with a centripetal blood supply from posterior ciliary arteries and drainage into the central retinal and optic nerve sheath veins. Association of nerve sheath veins with the choroid represents an important difference from the primate.  (+info)

Human ocular vasodynamic changes in light and darkness. (6/430)

PURPOSE: To determine whether changes in the retinal blood flow in light and darkness occur in humans. METHODS; The systolic and diastolic flow velocities were measured by color Doppler in the ophthalmic and the central retinal arteries in 12 healthy individuals in light and darkness. RESULTS: In the ophthalmic artery there was a trend toward lower systolic velocity in darkness compared with that in the light, but there was no change in diastolic velocity. In the central retinal artery the systolic and the diastolic flow velocities were markedly increased in darkness. After re-exposure to light the systolic flow velocity decreased. CONCLUSIONS: Darkness is associated with increased blood flow velocity in the central retinal artery, probably reflecting increased retinal metabolic demands by the photoreceptors.  (+info)

Retinal arteriolar diameters and elevated blood pressure: the Atherosclerosis Risk in Communities Study. (7/430)

Narrowing and other changes in retinal arterioles may reflect damage due to hypertension, which may predict stroke and other cardiovascular diseases independently of blood pressure level. Newly developed quantitative methods of assessing retinal narrowing are used to determine whether this sign is related only to current blood pressure or whether it also independently reflects the effects of previous blood pressure. Retinal photography was performed at the third examination of Atherosclerosis Risk in Communities (ARIC) Study in 1993-1995, and results are presented for the 9,300 nondiabetic participants aged 50-71 years. Generalized narrowing of smaller arterioles was strongly and monotonically related to current blood pressure in men and women, whether they were taking antihypertensive medications or not, and, independent of current blood pressure, was consistently and monotonically related to blood pressure levels measured 3 and 6 years before the retinal assessment. Arteriovenous nicking was also independently related to both current and previous blood pressures. The patterns of association suggested that these signs reflect both transient and persisting structural effects of elevated blood pressure, in agreement with the scant pathologic literature available. The findings suggest that retinal assessment may be useful for research on the microvascular contributions to clinical cardiovascular diseases.  (+info)

Susceptibility of weakly ouabain-sensitive Na, K-ATPase isoform in ischemic and reperfused rat retinas. (8/430)

It is possible that Na, K-ATPase may play some roles in ischemic damage of nervous tissue. To determine whether Na, K-ATPase is affected in ischemic and reperfused retina, we measured enzyme activities. Retinal ischemia was induced by clamping the optic nerve of female adult Sprague-Dawley (SD) rats for 90 minutes. At 0.5, 2 and 24 hours after reperfusion, rat eyes were enucleated, and the retinas were removed. In addition to unseparated, total ouabain-sensitive Na, K-ATPase activity, we measured weakly ouabain-sensitive (alpha) and highly ouabain-sensitive (alpha[+]) isoform activities separately by ATP hydrolysis. Total ouabain-sensitive Na, K-ATPase activity, alpha and alpha(+) isoform activities showed no significant difference from sham-operated contralateral eyes at 0.5 and 2 hours of reperfusion. After 24 hours of reperfusion, total ouabain-sensitive Na, K-ATPase activity decreased to 63% of the control. The activities of alpha and alpha(+) isoforms were 47% and 72%, respectively. The ratios of the alpha and alpha(+) isoform activities (alpha/alpha[+]) significantly decreased at 2 and 24 hours of reperfusion. Activity in a isoform decreased markedly in reperfused rat retinas. This response may be beneficial for reducting the oxidative stress in reperfused retinas.  (+info)