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Dive into the research topics where John G. Clarkson is active.

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Featured researches published by John G. Clarkson.


Ophthalmology | 1987

Microbial Endophthalmitis Resulting from Ocular Trauma

John C. Affeldt; Harry W. Flynn; Richard K. Forster; Sid Mandelbaum; John G. Clarkson; Glen Jarus

Twenty-seven cases of culture-positive endophthalmitis that developed after ocular trauma were reviewed. The intraocular culture specimens showed a virulent microbiologic spectrum with Bacillus sp as the most common isolate (8 eyes). The visual prognosis was poor, with only 22% of patients retaining 20/400 or better vision. This level of vision was achieved in 2 of 22 (9%) bacterial cases and in four of five (80%) fungal cases. Retinal detachment (5 cases) or retinal breaks (2 cases) at the time of the initial injury had a uniformly poor visual prognosis. Postoperative retinal detachment not associated with phthisis bulbi occurred in five eyes, three of which had successful retinal reattachment surgery. Delayed onset retinal detachment after successful initial management of traumatic endophthalmitis had a greater frequency of successful retinal reattachment surgery.


Ophthalmology | 1982

The Acute Retinal Necrosis Syndrome Part 1: Clinical Manifestations

Jerome P. Fisher; Mary Lou Lewis; Mark S. Blumenkranz; William W. Culbertson; Harry W. Flynn; John G. Clarkson; J. Donald M. Gass; Edward W.D. Norton

The acute retinal necrosis syndrome is characterized by necrotizing retinitis, vitritis, and retinal vasculitis occurring in otherwise healthy patients. Experience with 11 cases and the review of 30 additional cases in the literature are presented. In this series, 50% of the affected eyes developed retinal detachments, and 64% had a final visual acuity of less than 20/200. The natural history, diagnosis, postulated etiology, and suggestions for management will be discussed.


Ophthalmology | 1986

Treatment of the Acute Retinal Necrosis Syndrome with Intravenous Acyclovir

Mark S. Blumenkranz; William W. Culbertson; John G. Clarkson; Richard D. Dix

We treated 13 eyes of 12 patients with the acute retinal necrosis syndrome (ARN) with intravenous acyclovir (1500 mg/M2/day) for an average of 10.9 days. All patients were also treated with oral aspirin or Coumadin. in an attempt to prevent thrombotic complications and nine of twelve patients were treated with oral prednisone after intravenous acyclovir had been initiated. Regression of retinal lesions was first seen on average 3.9 days after initiation of therapy and required 32.5 days on average for completion. No eye developed new retinal lesions or progressive optic nerve involvement 48 hours or more after initiation of therapy, although progression within the first 48 hours was occasionally seen. Treatment did not ameliorate vitritis or prevent retinal detachment, which occurred in 11 of 13 eyes, an average of 59 days after the initiation of therapy. There were no evident ocular or systemic complications of therapy. Our data suggest the need for a prospective randomized clinical trial to evaluate the efficacy of intravenous or oral acyclovir in the treatment of the acute retinal necrosis syndrome.


Ophthalmology | 1984

Retinal Detachment Following the Acute Retinal Necrosis Syndrome

John G. Clarkson; Mark S. Blumenkranz; William W. Culbertson; Harry W. Flynn; Mary Lou Lewis

Twenty-six patients with the acute retinal necrosis involving 32 eyes have been followed at the Bascom Palmer Eye Institute. Sixteen eyes developed retinal detachment and surgical repair was attempted in thirteen. Ten eyes were successfully reattached. Vitreous surgery was necessary in ten eyes and was performed in eight of the ten successful eyes. The clinical characteristics of the retinal detachments as well as the surgical procedures and results are presented.


Retina-the Journal of Retinal and Vitreous Diseases | 1984

Multifocal Pigment Epithelial Detachments By Reticulum Cell Sarcoma: A Characteristic Funduscopic Picture

J. Donald M. Gass; Raymond J. Sever; W. Sanderson Grizzard; John G. Clarkson; Mark S. Blumenkranz; Chiel A. Wind; Richard Shugarman

Patients with systemic reticulum cell sarcoma often develop evidence of ocular involvement months or several years prior to the onset of neurologic symptoms. This neoplasm appears to have proclivity of arising multicentrically within the subpigment epithelial space, as well as in the vitreous. When this occurs it may produce a peculiar ophthalmoscopic picture of multiple large, solid detachments of the pigment epithelium that is rarely duplicated by any other disease. Three patients illustrating this disease are presented. RETINA 4:135-143, 1984


Ophthalmology | 1990

Endogenous Candida Endophthalmitis Management without Intravenous Amphotericin B

Roy D. Brod; Harry W. Flynn; John G. Clarkson; Stephen C. Pflugfelder; William W. Culbertson; Darlene Miller

Eight consecutive cases of culture-proven endogenous Candida endophthalmitis (ECE) were managed between 1980 and 1988. All patients were treated with vitrectomy and injection of intravitreal amphotericin B. Blood cultures were negative in all patients, although Candida albicans was cultured from a foot ulcer in one patient. No systemic therapy was used in three patients, three patients received oral ketoconazole, and two patients received oral flucytosine postoperatively. Intravenous amphotericin B was not used because of lack of evidence of disseminated candidiasis and the systemic toxicity associated with its use. The ECE responded favorably to treatment in all cases. Final vision was better in patients with a shorter interval between onset of symptoms and initiation of antifungal therapy. Posttreatment visual acuities were: four eyes greater than or equal to 20/50, two eyes at 20/80 to 20/200, and two eyes less than 5/200. This series showed that ECE without evidence of disseminated disease can be treated successfully with vitrectomy and intravitreal amphotericin B.


Ophthalmology | 1989

Classification of Proliferative Vitreoretinopathy Used in the Silicone Study

John S. Lean; Walter H. Stern; Alexander R. Irvine; Stanley P. Azen; Stanely P. Azen; William E. Barlow; Donna C. Boone; Beth Quillen-Thomas; M.S. Cox; M.S. Blumenkranz; R.R. Margherio; P.L. Murphy; M.T. Trese; George W. Blankenship; John G. Clarkson; Harry W. Flynn; Brooks W. McCuen; Banks Anderson; E. deJuan; Robert Machemer; Einar Stefánsson; James S. Tiedeman; Travis A. Meredith; Thomas M. Aaberg; Henry J. Kaplan; Paul Sternberg; H.M. Freeman; F.I. Tolentino; Bert M. Glaser; Serge deBustros

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.


American Journal of Ophthalmology | 1992

Results and Complications in Treated Retinal Breaks

William E. Smiddy; Harry W. Flynn; Don H. Nicholson; John G. Clarkson; J. Donald M. Gass; Kai R. Olsen; William J. Feuer

One hundred sixty-four patients (171 eyes) were treated for retinal breaks and the treatment outcomes were studied. One hundred two eyes were acutely symptomatic, 22 eyes were chronically symptomatic, and 47 eyes were asymptomatic. The reasons for further treatment in 38 of the 171 eyes (22%) included the following: (1) inadequate closure of the original break without detachment in eight eyes (5%), (2) new breaks without detachment in 15 eyes (9%), (3) an operation for retinal detachment caused by the original break in seven eyes (4%), or (4) retinal detachment caused by a new break in eight eyes (5%). Failure rates of treatment among acutely symptomatic, chronically symptomatic, and asymptomatic subgroups were not statistically significant. The risk of treatment failure was higher for aphakic and pseudophakic eyes, and in eyes with peripheral retinal abnormalities in the fellow eye. Among 38 patients with failed treatments, 20 (52%) returned for further examination within one month of initial treatment, whereas eight of the 38 patients with failed treatments (21%) returned six months or more after initial treatment. Peripheral retinal abnormalities were recognized initially in 65 of the 171 fellow eyes (38%) and subsequently developed in nine of the fellow eyes (5%) during the follow-up interval. Further treatment is often necessary after initial treatment of peripheral retinal breaks, emphasizing the need for careful long-term follow-up care.


American Journal of Ophthalmology | 1980

Vitrectomy in Terson's syndrome

John G. Clarkson; Harry W. Flynn; Mark J. Daily

Five patients with nonclearing vitreous hemorrhage associated with subarachnoid or subdural hemorrhages (Tersons syndrome) underwent pars plana vitrectomy. All six eyes of the five patients had postoperatively improved visual acuity and visual function. We recommend treating this rare syndrome with vitrectomy after careful preoperative ophthalmologic examination and a minimum observation period of six months to one year.


Ophthalmology | 1991

Evaluation of eyes with advanced stages of retinopathy of prematurity using standardized echography.

Jose S. Pulido; Sandra Frazier Byrne; John G. Clarkson; Cathy L. Di Bernardo; Colleen A. Howe

The authors evaluated 36 patients (72 eyes) who had either Stage 4 or Stage 5 retinopathy of prematurity (ROP) with standardized A-scan and B-scan echography. The eyes were evaluated for vitreous opacities, retrolental membranes, and retinal detachments. Stage 5 retinal detachments were present in 94% (68 of 72) of the eyes with 65% (47 of 72) having a wide anterior and narrow posterior configuration. Anterior retinal loops were noted in 36% of the eyes. Subretinal opacities were present in 47% of the eyes. Choroidal thickening and intraocular calcium were noted in 22% and 14% of eyes, respectively. The axial eye length was measured and adjusted for the differences in chronological and gestational age and compared with data from normal eyes. This showed that eyes with ROP were much smaller. The standardized A-scan was helpful in confirming the diagnosis of retinal detachment, evaluating the peripheral retina, and examining the subretinal space. The combination of A-scan and B-scan echography is helpful in predicting anatomic findings in patients with ROP undergoing surgery.

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Paul Rodgers

University of Cambridge

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