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Repair of retinal detachment caused by cytomegalovirus retinitis in patients with the acquired immunodeficiency syndrome.

Twenty-two eyes of 19 patients with the acquired immunodeficiency syndrome who had pars plana vitrectomy and silicone-oil injection after retinal detachment caused by cytomegalovirus retinitis were studied. All patients but one were monitored until time of death. The postoperative survival time and the factors that predicted anatomic success (retinal attachment) and functional success (visual acuity) were analyzed. No intraoperative complications were encountered. The mean survival time after surgery was four months. Of all of the preoperative and intraoperative factors studied, only the duration of cytomegalovirus retinitis was predictive of survival (P less than .03). The anatomic success rate was 89.5% (17 of 19 patients). None of the factors showed a trend or statistical significance in relation to anatomic success. Fifteen of 19 patients (79%) had lost at least two lines of Snellen visual acuity at time of death. Vision declined in a bimodal pattern (within the first postoperative month and after four months postoperatively). The optic nerve was pink and well perfused preoperatively in 16 of 19 patients (81.8%), but optic-nerve atrophy was observed postoperatively in 18 of 19 patients (95.5%). There was a trend for functional success to be influenced by increased intraocular pressure and optic-nerve atrophy, although our sample size was too small for statistical significance.

Acquired Immunodeficiency Syndrome↗

Central retinal artery occlusion. Retinal survival time.

PURPOSE: To investigate the retinal survival time following central retinal artery occlusion (CRAO). METHODS: In 38 elderly, atherosclerotic and hypertensive rhesus monkeys, transient CRAO (varying from 97 to 240 min) was produced by temporarily clamping the CRA at its site of entry into the optic nerve. Stereoscopic color fundus photography, fluorescein fundus angiography, electroretinography (ERG), and visual evoked potential (VEP) recording were performed before and during CRA clamping, after unclamping, and serially thereafter. After unclamping of the CRA, the animals were followed for variable lengths of time (median duration 8.14 weeks). Finally, the eyes and optic nerves were examined histologically. The data on ERG changes were analyzed in the following four time frames: (1) baseline before CRA clamping, (2) during CRA clamping, (3) immediately after unclamping, and (4) at the end of follow-up. Duration of CRAO was divided into four groups: 97, 105-120, 150-165, and > or = 180 min. RESULTS: A 'negative ERG' appeared during CRA clamping. With removal of the CRA clamp, there was b-wave recovery, with differential rates of recovery of ERG-eyes with shorter CRAO recovered sooner than those with longer occlusion. On removal of clamp, recovery was seen in scotopic 24 dB b-wave, photopic 0 dB single flash b-wave and 30 Hz flicker, with the b/a ratio of the combined rod and cone response and selective rod response showing statistically significant differences amongst the shorter and longer periods of CRAO. A delayed normalization of the depressed b/a ratio immediately after CRA reperfusion may indicate high-grade ischemic damage. At the final follow-up test session, no clear-cut derangement of any ERG parameter was seen for any group, with subtotal b-wave amplitude recovery for all groups. Longer CRAO produced incomplete VEP recovery. On histology, in the macular retina, eyes with CRAO for 97 min showed practically no damage, but duration of CRAO was found to be significantly associated with the amount of damage in the ganglion cell layer (p = 0.009) and inner nuclear layer (p = 0.017). Outer nuclear and plexiform layers and photoreceptors showed no damage at all with CRAO. There was no significant association of the ERG measures and histologic changes with any of the residual retinal circulation variables. CONCLUSIONS: Our electrophysiologic, histopathologic and morphometric studies showed that the retina of old, atherosclerotic, hypertensive rhesus monkeys suffers no detectable damage with CRAO of 97 min but above that level, the longer the CRAO, the more extensive the irreversible damage. The study suggests that CRAO lasting for about 240 min results in massive irreversible retinal damage.

Animals↗

Blood-retinal barrier breakdown following experimental retinal ischemia and reperfusion.

The purpose of this study was to examine the effects of acute ischemia and reperfusion on blood-retinal barrier (BRB) function in the rabbit eye. Hydrostatic pressure (140 mmHg) was used to create total retinal ischemia for intervals of 20, 40, 60, 80 or 100 min in the rabbit eye. The location, size and permeability-surface-area product normalized to the area of retinal leakage (PS') of ischemia-induced BRB lesions were then measured using contrast-enhanced magnetic resonance imaging (MRI) after various intervals of reperfusion. Diffuse outer BRB leakage occurred in most eyes subjected to 80 or 100 min of ischemia. A posterior region of outer BRB sparing was found in eyes that underwent lesser durations of ischemia. On day 1 after retinal ischemia, a linear relationship was found between mean PS' and duration of ischemia for periods of ischemia between 20 and 100 min [slope: 5.65 x 10(-6) to 5.96 x 10(-6) cm min-1 (min ischemia)-1; r2 > or = 0.69]. Lesion size also increased between 20 and 100 min of ischemia. In a longitudinal study, eyes exposed to 60 min of ischemia showed a decrease in PS' and a lesion size over an 8-week period of observation. However, leakage was still present on post-ischemia day 57 in two of three eyes examined. Data obtained in these experiments are expected to prove useful in future studies aimed at understanding how BRB damage relates to neuroretinal damage after ischemia-reperfusion injury.

Animals↗

Retinal ganglion cell death induced by retinal ischemia. neuroprotective effects of two alpha-2 agonists.

We have investigated in adult Sprague-Dawley rats the neuroprotective effects of two alpha-2-selective agonists [AGN 191,103 (AGN) and brimonidine tartrate (BMD)] on retinal ganglion cell (RGC) survival after transient retinal ischemia. RGCs were labelled with Fluorogold (FG) applied to both superior colliculi. Seven days later, 90 min of retinal ischemia were induced in the left eyes by ligature of the ophthalmic vessels (LOV). In one group of animals, vehicle or AGN (0.01 mg/kg) were administered systemically 1 hr before ischemia. In another group of animals, two 5 microl drops of vehicle, AGN (0.05%) or BMD (0.1%) were administered topically in the left eye 1 hr before ischemia. The animals were processed 7 or 21 days later. RGC survival was estimated by counting FG-labelled cells in 12 standard areas of each retina. In control retinas of systemically pretreated animals, mean densities of labelled RGCs were 2372 +/- 49 cells/mm(2) (mean +/- SEM; n = 6). In experimental retinas of systemically pretreated animals, mean RGC densities had decreased 7 days after ischemia to 53% (n = 6) or 81% (n = 6) of control in the groups treated with vehicle or AGN, respectively. Twenty-one days after ischemia, mean RGC densities had decreased to 38% (n = 6) or 79% (n = 6) of control in the groups treated with vehicle or AGN, respectively. In control retinas of topically pretreated animals, mean densities of labelled RGCs were 2208 +/- 29 cells/mm(2) (n = 6). In experimental retinas of topically pretreated animals, mean RGC densities had decreased 7 days after ischemia to 54% (n = 6), 95% (n = 6) or 96% (n = 6) of control in the groups treated with vehicle, AGN or BMD, respectively. These results indicate that pretreatment with a single systemic or topical dose of AGN or BMD can prevent completely the early rapid phase of RGC loss and abolish the delayed RGC loss observed after 90 min of retinal ischemia induced by ligature of the ophthalmic vessels.

Administration, Topical↗

Metabolic studies on retinal tissue from a donor with a dominantly inherited chorioretinal degeneration resembling sectoral retinitis pigmentosa.

Protein synthesis, glycosylation, RNA synthesis, and neurotransmitter uptake were monitored using biochemical and autoradiographic techniques following in vitro labeling of retinal tissue from a 79-year-old female with sectoral retinitis pigmentosa (RP). Comparisons were made between degenerate and non-degenerate regions of the RP retina, and normal retinal tissues from an age- and postmortem-matched donor. Autoradiographs of non-degenerate retina from the RP eye following 3H-uridine incubation revealed virtually identical silver grain density over nuclei in all retinal strata as compared to normal control retinas. In contrast, a photoreceptor-specific reduction in silver grain density in the non-degenerate RP retina was noted following 3H-leucine incubation. In the normal retina, rod photoreceptor labeling with 3H-mannose was always greater than cone photoreceptor labeling. This pattern of incorporation was reversed in the non-degenerate region of the RP retina where rod photoreceptor labeling was less pronounced than that observed for cone photoreceptors. In non-degenerate regions of the RP retina, a marked accumulation of 3H-GABA by the Müller's cells was observed. Few cells exhibited selective uptake of 3H-muscimol, a GABA analog, indicating that few GABAergic neurons remained in the degenerate retina. 3H-dopamine-accumulating cell terminals were observed in the usual positions in the non-degenerate RP retina. In the degenerate region of the RP retina, heavy and diffuse uptake of 3H-GABA and 3H-muscimol, respectively, into broad cellular processes were noted, whereas 3H-dopamine was accumulated by only a few punctate terminals.

Aged↗

The surface morphology of retinal breaks and lattice retinal degeneration. A scanning electron microscopic study.

In 14 of 110 eye bank eyes, lesions characteristic of peripheral retinal surface pathology were examined by scanning electron microscopy (SEM). These included operculated and flap tears, trophic round holes, lattice degeneration with holes, and paravascular retinal "pitting" degeneration. By SEM, the edges of the retinal breaks were covered by smooth cellular membranes, merging peripherally with a meshwork of vitreous fibrils. The membrane cells had poorly defined borders, a pitted surface, and variable numbers of microvilli consistent with glia. Lattice surfaces and foci of paravascular retinal degeneration were covered by similar membrane, but showed characteristic differences. It appears that breaks in the internal limiting membrane always stimulate proliferation of preretinal glial membranes. Similar cellular morphology of the membranes associated with breaks is consistent with a common cell of origin. Limited proliferation of these membranes suggests that surface gliosis is normally inhibited when the cells contact either intact basement membrane or vitreous.

Cell Membrane↗

Retinal vascular changes in congenital hypertrophy of the retinal pigment epithelium.

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.

Adolescent↗

Retinal patching: a new approach to the management of selected retinal breaks.

Restoration of retinal continuity by a patching technique is proposed as a new means of treating selected rhegmatogenous retinal detachments where established techniques frequently fail. The patch consists of a substrate and adhesive applied to the inner surface of the retina surrounding the retinal break. Bovine eye cup experiments have been performed to explore the effectiveness of a range of adhesives, and cyanoacrylates and Tisseel have been found to be effective. Studies of these adhesives on confluent cultures of bovine retinal pigment epithelial cells and glia revealed temporary cyanoacrylate toxicity and stimulation of proliferation by Tisseel. Substrate biocompatability was investigated by observing the growth of cells on various substrates in tissue culture; biological substrates such as lens capsule supported cell growth whereas synthetic membranes only did so if pretreated with fibronectin.

Animals↗

Management of viral retinitis-associated retinal detachment in AIDS.

We retrospectively reviewed the results of surgery in 27 cases of retinal detachment related to viral necrotising retinitis in acquired immune deficiency syndrome (AIDS). Vitrectomy and silicone oil tamponade were performed in all cases. Scleral buckling was applied to 9 eyes. Silicone oil was left in the eye in all cases. Mean follow-up period was 13 weeks. Post-operative flattening of the retina at the posterior pole was achieved in 89% of the eyes. Anatomical results were not related to the intraoperative use of an encircling procedure. Visual acuity improved by 2 Snellen lines or more in 40% of cases and 67% of the eyes retained a post-operative ambulatory vision. Phacosclerosis and optic atrophy developed in 29% and 22% of cases, respectively. Vitrectomy and silicone oil tamponade without scleral buckling are effective in the management of retinitis-associated retinal detachments. This procedure is short and can be performed under local anaesthesia.

AIDS-Related Opportunistic Infections↗

Bone marrow-derived stem cells target retinal astrocytes and can promote or inhibit retinal angiogenesis.

Adult bone marrow (BM) contains cells capable of differentiating along hematopoietic (Lin(+)) or non-hematopoietic (Lin(-)) lineages. Lin(-) hematopoietic stem cells (HSCs) have recently been shown to contain a population of endothelial precursor cells (EPCs) capable of forming blood vessels. Here we show that intravitreally injected Lin(-) BM cells selectively target retinal astrocytes, cells that serve as a template for both developmental and injury-associated retinal angiogenesis. When Lin(-) BM cells were injected into neonatal mouse eyes, they extensively and stably incorporated into forming retinal vasculature. When EPC-enriched HSCs were injected into the eyes of neonatal rd/rd mice, whose vasculature ordinarily degenerates with age, they rescued and maintained a normal vasculature. In contrast, normal retinal angiogenesis was inhibited when EPCs expressing a potent angiostatic protein were injected. We have demonstrated that Lin(-) BM cells and astrocytes specifically interact with one another during normal angiogenesis and pathological vascular degeneration in the retina. Selective targeting with Lin(-) HSC may be a useful therapeutic approach for the treatment of many ocular diseases.

Animals↗

Scleral buckling combined with vitrectomy for the management of rhegmatogenous retinal detachment associated with inferior retinal breaks.

AIM: The use of adjunctive scleral buckling during vitrectomy for retinal detachment associated with inferior breaks has been the recent focus of some debate. It has been suggested that any benefit might be outweighed by potential complications associated with buckling surgery. The purpose of this study was to compare the success rate of vitrectomy, gas, and supplementary scleral buckling with the results of two recently published case series suggesting that acceptable results in inferior break detachments can be achieved with vitrectomy and gas alone. METHODS: A retrospective analysis of 60 consecutive patients with inferior break retinal detachments was conducted. All patients underwent vitrectomy, gas, and scleral buckling. In all cases, fellow eyes were examined under anaesthesia for retinal breaks if posterior vitreous detachment (PVD) had occurred at the time of presentation. Demographics, preoperative, and postoperative complications and outcome were recorded. RESULTS: Primary retinal attachment at 3 months was achieved in 95% of patients. This exceeds success rates of published data of patients who underwent vitrectomy and gas without buckling (81-89%). In patients with PVD in the fellow eye, 53% had horseshoe tears and all were treated with cryopexy. No sight-threatening complications occurred, but five patients developed minor buckle-related complications postoperatively. CONCLUSION: Supplementary scleral buckling is a safe procedure that improves and enhances primary success rates in inferior break detachments over vitrectomy and gas without buckling. There is a high rate of PVD-related breaks requiring treatment in the fellow eyes.

Female↗

Increased expression of retinal TIMP3 mRNA in simplex retinitis pigmentosa is localized to photoreceptor-retaining regions.

The human tissue inhibitor of metalloproteinases-3 (TIMP3) gene is the most recently characterized member of a family of genes whose products are implicated in extracellular matrix (ECM) remodelling. We previously described an increase in expression of TIMP3 mRNA in retinas affected by the progressive photoreceptor degenerative disease, simplex retinitis pigmentosa (RP). To gain further insight into the association between TIMP3 overexpression and retinal degeneration, we have analyzed the cellular localization of TIMP3 mRNA in control and simplex RP retinas using in situ hybridization. No TIMP3 mRNA expression was detectable in control neural retina. IN RP-affected retinas, overexpression of TIMP3 mRNA was observed in photoreceptor inner segments and in the ganglion cell layer only in those regions retaining relatively nondystrophic retinal architecture. Modulation of TIMP3 expression in these regions, possibly in association with matrix metalloproteinases, may reflect remodelling of the retinal ECM and concomitant reorganization of neuronal connectivity.

Aged↗

[Posterior vitreous detachment with collapse, and peripheral retinal degeneration in the aetiology of idiopathic retinal detachment. A synapsis of clinical observations and anatomical studies (author's transl)].

The crucial aetiological factors of idiopathic retinal detachment are posterior vitreous detachment with collapse, and degenerative lesions in the fundus periphery. Posterior vitreous detachment does not imply diagnostic problems to the expert in this field. On the other hand, the peripheral retinal degenerations include wide range of lesions the clinical and pathoanatomical study of which has so far not resulted in a complete picture. The author of the present paper attempts to get closer to a clearly arranged classification and terminology of those peripheral retinal degenerations, which are of importance to the aetiology, prophylaxis and treatment of idiopathic retinal detachment.

Aged↗

Facilitation of retinal function recovery by natural products after temporary ischemic occlusion of central retinal artery.

The b-wave of electroretinogram (ERG) was used as an indicator of the retinal function in this research to study the facilitation of retinal function recovery by some natural products isolated from medicinal plants. The retinal ischemia was induced by occlusion of the central retinal artery. It was found that the recovery of b-waves was limited to approximately 30-37% in control animals, whereas the b-wave recovery was doubled by natural products, including scoparone, corylifolinin and EGCG (epigallocatechin-3-0-gallate). Lespedeza flavanone A had biphasic action by suppressing the b-wave recovery below control level initially, then enhancing the b-wave recovery over the control rate later. These results indicate that some natural products could be used for the treatment of ischemic retinopathy.

Animals↗

Vitrectomy for retinal detachments with both peripheral retinal breaks and macular holes. An assessment of outcome and the status of the macular hole.

PURPOSE: To establish the effectiveness of vitrectomy and gas tamponade for treating retinal detachments due to peripheral retinal breaks with an associated macular hole and to discover the status of the macular hole at long-term follow-up. METHODS: Twenty-three consecutive patients with combined peripheral break and macular hole retinal detachments were treated by pars plana vitrectomy. The main outcome measures were reattachment of the retina and status of the macular hole. RESULTS: Seventy-eight percent of the operations were successful in reattaching the retina initially, improving to 87% after two patients had another operation. Three patients declined further surgery. Long-term follow-up of macular hole status was possible in 16 cases. Closure rate was 31%. CONCLUSION: Pars plana vitrectomy with gas tamponade is an effective method of treating this form of retinal detachment. Some macular holes close after this surgery.

Adult↗

Retinal arteriolar tortuosity with retinal haemorrhage. A case report.

Retinal arteriolar tortuosity with retinal haemorrhages was first described in 1958. In the present article, a case of recurring retinal haemorrhages combined with retinal arteriolar tortuosity is reported. The medical examination and laboratory tests did not reveal pathology except for a slightly increased bleeding time. There were no similar cases in the family. The cause of the haemorrhages is still unknown.

Adolescent↗

Asymmetric retinitis pigmentosa, luetic retinopathy and the question of unilateral retinitis pigmentosa.

A seropositive patient with the fundus appearance of monocular luetic retinopathy is presented. Electrophysiologically, this patient shows a late-onset form of progressive tapetoretinal degeneration (retinitis pigmentosa) presenting in an extremely asymmetric manner. The differential diagnosis of luetic and other inflammatory retinopathies vs. tapetoretinal degenerations is briefly discussed. Features distinguishing unilateral retinitis pigmentosa from bilateral tapetoretinal degenerations are reviewed, and the existence of unilateral retinitis pigmentosa as a genetic entity is questioned. Prolongation of ERG- a- and b-wave implicit times is characteristic of the tapetoretinal degenerations, and normal implicit times in the fellow eye are suggested as an additional criterion for the diagnosis of unilateral retinitis pigmentosa.

Dark Adaptation↗

Fluorescein angiography in homozygote and carrier state of progressive retinal atrophy of the poodle; comparative aspects with human retinitis pigmentosa.

Fluorescein angiographic findings in 7 carriers and 7 homozygotes of a recessively inherited disease, generalized progressive retinal atrophy of the poodle, are described in detail and comparisons with 24 healthy control poodles are presented. Two angiographic types of the disease could be distinguished. These are: Type 1, a diffuse, widespread choriocapillaris atrophy associated with retinal vascular and depigmentation changes and Type 2, a predominantly retinal involvement combined with focal choroidal atrophic patches lineating major vessels. These findings share similarities with the observations made of the human disease, retinitis pigmentosa. Unaffected carriers of the disease showed characteristic fundus changes in angiography: patchy, hyperfluorescent depigmentation changes and often minor narrowing and irregularities of the arterioles and poorly visible capillary bed.

Animals↗