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Biomedical subjects

A R Irvine

Publications and source records attributed to A R Irvine.

At least 19 recordsLinked to original sources
PubMed1992

Extramacular disciform lesions simulating uveal tumors.

PURPOSE: The purpose of this study is to identify clinical, ultrasonographic, and fluorescein angiographic features of extramacular disciform lesions that allow differentiation from uveal tumors. METHODS: This was a retrospective study of 19 patients referred to our ocular oncology unit with a possible malignancy who had a diagnosis of an extramacular disciform lesion made after complete evaluation. RESULTS: The level of accuracy for each diagnostic technique alone was as follows: clinical (79%), ultrasonography (83%), and angiography (83%). Fluorescein angiography had limited utility because of severe media opacities in seven cases. No tumor developed an intraocular malignancy during the follow-up period. CONCLUSION: A combination of the above, noninvasive techniques can be used to correctly diagnose extramacular disciform lesions.

Adult↗
PubMed1991

Varicella-zoster virus retinitis in patients with the acquired immunodeficiency syndrome.

We examined five patients infected with the human immunodeficiency virus who developed a rapidly progressive necrotizing retinitis characterized by early patchy choroidal and deep retinal lesions and late diffuse thickening of the retina. In all but one case, the retinitis began in the posterior pole with little or no clinical evidence of vasculitis. All five patients had relentless progression of disease and were left with atrophic and necrotic retinae, pale optic-nerve heads, and narrowed vasculature. None of the patients developed aqueous or vitreal inflammation or retinal detachment. Clinical and laboratory evidence suggested that varicella-zoster virus was the causal agent in all five cases. First, the onset of retinitis in four cases either succeeded or was coincident with an eruption of dermatomal zoster. Second, varicella-zoster virus was cultured from the two chorioretinal specimens and varicella-zoster virus antigen was detected in the vitreal aspirate from one case. Third, by means of immunocytochemistry, varicella-zoster virus antigen was found in the outer retinae of both enucleation specimens. Fourth, viral capsids with the size and shape of herpesviridae were found in the outer retinae of both enucleation specimens. The clinical features observed in this study are distinct from those described for the acute retinal necrosis syndrome and appear to constitute a new and highly characteristic pattern of varicella-zoster virus-induced disease.

Acquired Immunodeficiency Syndrome↗
PubMed1991

An updated classification of retinal detachment with proliferative vitreoretinopathy.

The Retinal Society classification on proliferative vitreoretinopathy of 1983 has been updated to accommodate major progress in understanding of this disease. There are three grades describing increasing severity of the disease. Posterior and anterior location of the proliferations have been emphasized. A more detailed description of posterior and anterior contractions has been made possible by adding contraction types such as focal, diffuse, subretinal, circumferential contraction, and anterior displacement. The extent of the abnormality has been detailed by using clock hours instead of quadrants.

Eye Diseases↗
PubMed1990

Five-year follow-up of helium ion therapy for uveal melanoma.

One hundred sixty-four patients with uveal melanoma were treated with helium ion irradiation prior to May 1984, and the data were analyzed in June 1989. Most uveal melanomas were large, with a mean tumor thickness of 6.5 mm; approximately 60% of the patients had tumors that extended anterior to the equator. A complete follow-up was obtained for all patients. One hundred twelve patients were alive at the time of this report; 18% of the patients developed clinical and laboratory evidence of metastases and eventually died of widespread tumor. Eighty-four percent of eyes were retained. Data were analyzed with a number of parametric and nonparametric techniques. Larger tumors and those located in close proximity to the optic nerve and fovea had a higher incidence of most complications, especially visual loss.

Adult↗
PubMed1989

Effect of various doses of radiation for uveal melanoma on regression, visual acuity, complications, and survival.

We reviewed 284 choroidal and ciliary body melanomas treated with 50, 60, 70, or 80 gray equivalents (GyE) of helium ion radiation. Multivariate methods of data analysis were used to adjust for differences between dose groups with respect to the characteristics of patients (and their tumors). Radiation dose level did not affect survival, complications, visual outcome, or tumor regression in this model. The minimum radiation dose necessary to achieve tumor control with charged particles may be less than 50 GyE.

Dose-Response Relationship, Radiation↗
PubMed1989

Classification of proliferative vitreoretinopathy used in the silicone study. The Silicone Study Group.

The Silicone Study is a multicenter randomized clinical trial that compares a long-acting gas with silicone oil for the surgical treatment of proliferative vitreoretinopathy (PVR). As part of the study, a topographic classification of PVR has been developed that is based on the characteristic patterns of retinal distortion produced by the contraction of proliferative membranes on the retina or within the vitreous base. This classification is used to document the extent and anatomic distribution of PVR present preoperatively and to help standardize the surgical treatment. Experience has shown that this classification facilitates the identification of these membranes and their systematic dissection, and the authors therefore suggest that it be used to augment the Retina Society classification of PVR.

Humans↗
PubMed1989

The validity and reliability of photographic documentation of proliferative vitreoretinopathy.

The Silicone Study is a multicentered, randomized surgical trial designed to compare the tamponade effectiveness of silicone oil versus long-acting gas in the treatment of proliferative vitreoretinopathy (PVR) by vitrectomy and associated techniques. Fundus photographs are taken to provide documentation of the anatomic status of eyes proposed for entry and are graded at an independent Reading Center. This article describes the protocol for photographic documentation of PVR as a continuum of increasing pathology, in which the pathology may only be present in the anterior retina, and the retina is usually highly elevated. In a validity and reliability study, agreement between photographic and clinical observation within one step was obtained for 88% of the eyes; intra- and inter-observer agreement within one step was 85 and 80%, respectively. Differences between the surgeon's grade and the Reading Center's were caused about equally by disagreement regarding extent of fixed folds and width of the funnel. Rarely did peripheral folds not visible in the photographs appear to be the sole explanation of the disagreement. Differences among readers were concerned mainly with differentiation of true full-thickness fixed folds from folds due to simple redundancy of the detached retina. These results demonstrate that complicated retinal detachment (RD) can be photographically documented and independently assessed.

Clinical Trials as Topic↗
PubMed1989

Uveal melanoma radiation. 125I brachytherapy versus helium ion irradiation.

The optimum radiation therapy for uveal melanoma is uncertain. Both helium ion irradiation and 125I brachytherapy have been used to treat this neoplasm. This investigation analyzed the control and complication rates of uveal melanomas treated with helium ions of 125I plaques. In both a retrospective and a prospective dynamically balanced study, the control rates appeared to be similar. There were more posterior segment complications after 125I plaques and more anterior segment complications, including neovascular glaucoma, after helium ion irradiation. The follow-up period is too short to draw definitive conclusions on the radiation complications. Overall, approximately 89% of eyes were retained and less than 4% of treated eyes were removed because of failure to control the tumor.

Adult↗
PubMed1988

Retinal phototoxicity from the operating microscope. The role of inspired oxygen.

The effect of the inspired oxygen concentration (FIO2) on the production of retinal phototoxicity by the operating microscope was studied in phakic rhesus monkeys. One eye of each monkey was exposed to light under conditions of 99% FIO2, and the other eye was exposed under 21% oxygen (O2). Three of four locations on each retina were exposed to light for durations varying from 1 1/2 to 20 minutes per exposure. Fundus photographs and fluorescein angiograms were obtained 24 to 72 hours after exposure. Animals were euthanatized for analysis of retinal histopathology at intervals from 2 weeks to 8 months after light exposure. Retinal phototoxic lesions were produced after an average of 5 minutes of light exposure under both 21 and 99% O2. O2 potentiated the light damage both clinically and histologically. Under both conditions, lesion size was directly related to the duration of light exposure (P less than 0.005). Lesions near threshold produced with 99% FIO2 were 1.6 to 6.9 (mean, 2.9) times larger than the corresponding lesions formed with 21% FIO2. Histologic damage was likewise more severe in lesions produced under high O2 conditions. Retinal repair occurred in lesions produced under high and low O2 conditions. Photoreceptor regeneration was nearly complete by 18 weeks, whereas retinal pigment epithelial (RPE) recovery lagged up to 1 1/2 months. The results of this study have important implications for clinical practice: the operating microscope can produce retinal phototoxicity rapidly, and O2 administered during ophthalmic procedures may potentiate the damage if appropriate precautions are not taken.

Animals↗
PubMed1988

Acute retinal necrosis syndrome presenting with papillitis and arcuate neuroretinitis.

Acute retinal necrosis (ARN) syndrome is a diffuse uveitis characterized by a peripheral necrotizing retinitis and retinal vasculitis. The authors document and discuss a case of ARN syndrome that initially presented with remarkable changes in the peripapillary retinal nerve fiber layer that they have termed arcuate neuroretinitis. These changes consisted of a well-defined arcuate band of retinitis paralleling the course of a parafoveal nerve fiber bundle. Evaluation of serial serum antibody titers suggests HSV-2 as a possible causative agent in this unique presentation of ARN syndrome.

Acute Disease↗
PubMed1988

Retinal detachment due to firecracker injury.

Seven cases of retinal detachment due to firecracker injury are reported. Most involved young boys. Associated anterior segment changes as well as the nature of the retinal breaks attested to the similarity between firecracker injuries and blunt contusion injuries. Despite successful retinal reattachment in all cases, visual results were poor. To prevent visual loss from firecracker injury, educational programs directed to school age boys seem needed.

Adolescent↗
PubMed1987

Radiation retinopathy as an experimental model for ischemic proliferative retinopathy and rubeosis iridis.

We produced radiation retinopathy in capuchin monkeys and studied them with fluorescein angiography and light and electron microscopy. The animals were followed up from ten days to 3 1/2 years after radiation in order to determine whether this could provide an experimental model for other chronic ischemic-proliferative retinopathies, such as diabetes. The first change detected after radiation was the focal loss of capillary endothelial cells and pericytes. As the areas of acellular capillaries became confluent, cotton-wool spots became visible ophthalmoscopically. These increased in number and then faded away, leaving large areas of retinal capillary perfusion. Histologic studies showed occlusion first of the deeper, smaller retinal vessels and then gradually of the larger vessels. Intraretinal neovascularization as well as apparent recanalization then developed, but no new vessels extended through the internal limiting lamina into the vitreous. Rubeosis iridis with neovascular glaucoma developed 2 1/2 to 3 1/2 years postirradiation, and vitreous aspirate demonstrated a high level of angiogenic factor.

Animals↗
PubMed1987

Effectiveness of ketorolac tromethamine 0.5% ophthalmic solution for chronic aphakic and pseudophakic cystoid macular edema.

The effect of ketorolac tromethamine 0.5% ophthalmic solution (a new nonsteroidal anti-inflammatory agent) treatment was compared to placebo treatment in patients with chronic, angiographically proven aphakic or pseudophakic cystoid macular edema (visual acuity less than or equal to 20/40 for six months) during a three- to four-month double-masked, randomized study. Twenty-six patients completed this study without significant ocular or systemic toxicity. The improved distance visual acuity observed in the ketorolac treatment group (8/13 patients) was statistically different from the improved vision observed in the placebo treated group (1/13 patients) (P = .005). No patient on a regimen of ketorolac therapy had a significant decrease in Snellen distance visual acuity while on treatment, but two patients in the placebo group demonstrated a decrease in visual acuity of two lines or more. Fluorescein angiography was consistent with changes in visual acuity.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1987

Endolaser, cryopexy, and retinal reattachment in the air-filled eye. A clinicopathologic correlation.

We report the histopathology of intraocular argon blue-green laser photocoagulation lesions and transscleral cryopexy lesions in the air-filled human eye. Two days after treatment, the cryopexy lesions showed full-thickness retinal involvement, including disruption of the internal limiting lamina. The laser lesions showed full-thickness involvement as well. These observations emphasize the need for caution with thermal treatment modalities in the air-filled eye. Ophthalmoscopic examination 48 hours following vitrectomy, internal drainage of subretinal fluid, and gas fill of the vitreous cavity for diabetic macular detachment of several months' duration showed the retina to be attached. However, histopathologic examination revealed a thin layer of persistent subretinal fluid, demonstrating that it may take longer than is clinically apparent for true retinal reattachment to occur following gas tamponade of posterior retinal breaks. Prolonged gas tamponade may be necessary before retinal reattachment, with reestablishment of photoreceptor-pigment epithelial adherence, can be expected to help seal unrecognized or untreated posterior retinal breaks.

Choroid↗
PubMed1987

Histopathology of krypton red laser panretinal photocoagulation. A clinicopathologic correlation.

The histopathologic appearance of five-day-old and 14-day-old krypton red laser-created panretinal photocoagulation lesions in the diabetic human eye is described. The five-day-old lesions were examined near the equator. The 14-day-old lesions were near the temporal arcades and optic disc. Both groups of laser lesions showed a similar degree of damage and occlusion in the lamina choriocapillaris and deeper choroidal vessels. The 14-day-old posterior laser lesions showed outer retinal damage, whereas the five-day-old peripheral lesions showed full-thickness retinal involvement, probably because the peripheral retina is approximately half the thickness of the posterior retina. The five-day-old lesions showed no evidence of repair, whereas the 14-day-old lesions showed an adhesion formed with tight junctions binding Müller's fibers to retinal pigment epithelium.

Diabetic Retinopathy↗
PubMed1987

The management of subretinal gas following attempted pneumatic retinal reattachment.

Pneumatic retinopexy is a recently described procedure for treating retinal detachments with cryotherapy and intraocular gas injection, rather than scleral buckling. Prospective studies are underway to assess its safety and efficacy. One potential complication of this technique is persistent detachment due to subretinal gas. We report seven cases of subretinal gas following attempted pneumatic retinal reattachment. In all cases, multiple fish-egg gas bubbles were present following injection; some of these bubbles gained access to the subretinal space during the early postoperative period. The subretinal gas gave the detached retina a pearly, dome-shaped, refractive sheen. Three cases were managed by positioning the patients' heads to allow the subretinal gas to pass through the retinal break back into the vitreous cavity. One case underwent successful scleral buckling that closed the retinal break despite the presence of a small subretinal gas bubble. Three cases required vitrectomy, air-fluid exchange, and cryotherapy or endolaser treatment. In five of the seven eyes the retina was eventually reattached successfully.

Adult↗
PubMed1986

The diagnoses most commonly missed by ophthalmologists referring patients for fluorescein angiography.

A tally of misdiagnoses in patients referred to a fluorescein angiography service disclosed that three conditions made up the majority of all misdiagnoses. These conditions were chronic branch retinal vein obstruction, old or chronic central serous choroidopathy, and retinal arterial macroaneurysms with subretinal or subhyaloid hemorrhage. These three conditions proved to be talented mimics with a wide variety of presentations.

Aneurysm↗