PubMed Health⌕ Search

Biomedical subjects

J S Lean

Publications and source records attributed to J S Lean.

At least 19 recordsLinked to original sources
PubMed1993

Vitrectomy with silicone oil or perfluoropropane gas in eyes with severe proliferative vitreoretinopathy. Silicone Study Report 3.

Between 1985 and 1990, 340 eyes with rhegmatogenous retinal detachment (RRD) and severe (stage C3 or worse) proliferative vitreoretinopathy (PVR) were treated with vitrectomy and randomly selected to receive perfluoropropane gas or silicone oil; 183 eyes had undergone no prior vitrectomy (group 1), and 157 eyes had undergone prior vitrectomy with intraocular gas tamponade (group 2). No differences were found between eyes in the two groups in achieving visual acuity of 5/200 or better (44% vs. 39%), macular reattachment (78% vs. 77%), or complete retinal reattachment (67% for both groups). In group 1, 74 eyes achieved complete retinal reattachment after only one operation; 41 additional eyes achieved reattachment after a second surgical procedure. In group 2, these numbers were 74 and 26, respectively. Eyes treated successfully after more than one operation were less likely to regain a visual acuity of 5/200 or better than those successfully treated with one operation (P < 0.01). There was no difference in hypotony between groups, but keratopathy was more frequent in eyes in group 2 (P < 0.05). The results suggest that differences in outcomes between group 1 and group 2 eyes are not as great as previously believed.

Adult↗
PubMed1992

Posterior chorioretinopathy and retinal detachment after organ transplantation.

Four patients, three after renal transplantation and one after heart-lung transplantation, developed visual loss in both eyes associated with geographic zones of disruption and coarse clumping of the pigment epithelium in the posterior fundi. Secondary retinal detachment occurred bilaterally in three patients. Localized choroidal intravascular coagulation is the suspected but unproven cause.

Adult↗
PubMed1992

Incidence and management of glaucoma after intravitreal silicone oil injection for complicated retinal detachments.

BACKGROUND: Intravitreal silicone oil injection used for managing complicated retinal detachments can be associated with elevated intraocular pressure (IOP). This study was undertaken to determine the incidence of glaucoma in patients who underwent silicone oil injection, as well as to evaluate the effectiveness of medical and surgical therapy in patients in whom glaucoma developed. METHODS: The postoperative courses of 50 eyes of 47 consecutive patients who underwent pars plana vitrectomy and silicone oil injection for the management of complicated retinal detachments were reviewed retrospectively. The outcomes of patients who underwent silicone oil removal and/or glaucoma surgery also were evaluated. RESULTS: The mean overall postoperative IOP before any glaucoma surgery was 16.7 +/- 9.3 mmHg (range, 0 to 45 mmHg), with a mean follow-up of 16.6 +/- 12.1 months (range, 2 to 51 months). Twenty-four (48%) eyes had postoperative IOPs of at least 25 mmHg and IOP elevations of at least 10 mmHg above the preoperative levels. Twenty-one (42%) eyes underwent complete removal of silicone oil and/or glaucoma surgery to effect IOP control. The IOPs were controlled to 21 mmHg or less (but > 5 mmHg) in 8 of 14 eyes that underwent removal of silicone oil alone, in 3 of 5 eyes that underwent Molteno implantation, and in 1 eye that underwent Nd:YAG transscleral cyclophotocoagulation, but not in 1 eye that underwent a modified Schocket procedure (mean follow-up, 13.5 +/- 11.0 months; range, 0.2 to 33 months). CONCLUSION: Intraocular pressure elevation is a common occurrence after intravitreal silicone oil injection. The underlying mechanism may often be multifactorial in nature. Patients in whom uncontrolled IOP develops may benefit from aggressive medical and/or surgical treatment with silicone oil removal, glaucoma implants, or cyclodestructive procedures.

Adolescent↗
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↗
PubMed1991

Massive suprachoroidal hemorrhage with central retinal apposition. A clinical and echographic study.

We reviewed the charts of 18 patients diagnosed with a massive suprachoroidal hemorrhage (MSCH) with central retinal apposition (kissing configuration). Four cases occurred intraoperatively (expulsive), eight after a surgical procedure (delayed), and six associated with blunt or perforating injury (traumatic). In this study, echography was used to monitor the course of MSCH; the mean time for clot lysis was 14 days, and the mean duration of central retinal apposition was 15 days. The expulsive MSCHs were all allowed to resolve spontaneously, with good initial visual outcome in three of the four eyes in which they occurred. In the delayed MSCH group, the majority of patients attained their prehemorrhage visual acuity, with or without early surgical intervention. In the traumatic MSCH group, retinal detachment was a constant complication in all patients. All six patients in the traumatic MSCH group had a poor visual outcome, despite early surgical intervention in five patients. The results of this study suggest that not all MSCHs need to be drained surgically and that, when surgical drainage is indicated, echography may be a useful adjunct in determining the optimal time of drainage.

Adult↗
PubMed1991

Methods, statistical features, and baseline results of a standardized, multicentered ophthalmologic surgical trial: the Silicone Study.

This article describes the trial design and baseline results for the Silicone Study, a multicenter, randomized surgical trial designed to compare the effectiveness of silicone fluid versus long-acting gas in the treatment of proliferative vitreoretinopathy (PVR). Design features include (1) standardization of the surgical protocol to reduce intersurgeon variability, (2) formulation of a PVR clinical classification system relevant to modern vitreoretinal surgery, and (3) creation of a photographic protocol to document PVR pathology. Statistical issues affecting the analysis of the outcome data include (1) the addition of a second group of patients with more severely diseased eyes after the trial began, (2) the change to a different long-acting gas during the course of the trial, and (3) recurrent retinal detachments that require reoperations with the randomized treatment, and, in some instances, a crossover from the randomized to the alternate treatment. Demographic and baseline ocular characteristics are presented for the two groups under study.

Adult↗
PubMed1991

Combined Molteno implantation and pars plana vitrectomy for neovascular glaucomas.

Ten patients underwent combined Molteno implantation and pars plana vitrectomy as the primary nonlaser surgical treatment of neovascular glaucoma associated with diabetic retinopathy (9 patients) or central retinal vein occlusion (1 patient). Combined surgery was performed most frequently because media opacities precluded adequate preoperative retinal ablation. Follow-up ranged from 3 to 43 (mean +/- standard deviation, 18.0 +/- 13.2) months. Six patients achieved final intraocular pressures less than 22 mmHg. Visual acuities remained the same or improved in four patients. Four patients had uncomplicated courses. Among the other patients, complications included: recurrent vitreous hemorrhage and retinal detachment (3 patients each); hyphema (2 patients); and tube block, extensive fibrin formation, epiretinal membrane, and total retinal necrosis (1 patient each).

Adult↗
PubMed1991

Variations in clinical features of the Vogt-Koyanagi-Harada syndrome.

Forty-eight cases of the Vogt-Koyanagi-Harada (VKH) syndrome occurring in patients residing in southern California were reviewed. Thirty-six patients were Hispanic and 12 of other racial groups. Symptoms of meningismus, predominantly headache, were present in 32 (67%) cases, but the other characteristic neurologic symptoms, i.e., tinnitus and dysacusis, were present in only eight (17%) and six (13%) cases, respectively. Dermatologic changes were rare; vitiligo occurred in five (10%) patients, alopecia in six (13%), and poliosis in three (6%). In this patient population, extraocular signs and symptoms of the VKH syndrome, other than headache, were unusual. The ocular manifestations of the VKH syndrome are more constant and include iridocyclitis, vitritis, diffuse swelling of the choroid, serous retinal detachment, and optic disc hyperemia. Procedures that may aid in the diagnosis include lumbar puncture, fluorescein angiography, and standardized echography. The ophthalmologist must be prepared to make this diagnosis and initiate treatment with high-dose systemic steroids based on the typical ocular findings even in the absence of other (extraocular) manifestations of this disease.

Adolescent↗
PubMed1990

Intravitreal biocompatibility of mussel adhesive protein. A preliminary study.

Mussel adhesive protein (MAP) is a new tissue adhesive derived from the sea mussel Mytilus edulis. Rabbit eyes were injected intravitreally with 1 mg of MAP or balanced salt solution in order to determine the intraocular effects of this new biologic tissue adhesive. Two concentrations of MAP were used: one was undiluted and the other was diluted to a concentration of 1:10. A marked cellular inflammatory response, compared with the control eyes, was seen clinically in the vitreous cavity of animals in which MAP was used undiluted. This response persisted for up to two weeks and was suggestive of inflammatory response to a foreign protein. When MAP was used at a dilution of 1:10, a mild transient cellular reaction was observed in the vitreous; this cleared after seven days. There was no increase in intraocular pressure, and none of the eyes developed cataract or optic nerve damage. Fluorescein angiography demonstrated no vascular leakage and electroretinography was normal in all of the eyes at two weeks. Histopathologic evaluation of the eyes at 7 and 14 days after injection revealed localized cellular inflammation in the vitreous and adjacent retina when MAP was used undiluted, but no reaction in the control eyes or in eyes injected with MAP at 1:10 dilution. This preliminary study suggests that MAP produces a marked intraocular inflammatory reaction when used at full concentration. By diluting the adhesive, a less severe inflammatory response was observed, which cleared with no complications.

Animals↗
PubMed1990

Management of traumatic rupture of the globe in aphakic patients.

We report the successful treatment of three cases of traumatic ruptures of the globe complicated by massive choroidal hemorrhage, uveal prolapse and retinal detachment. All three of the eyes were aphakic prior to injury and all patients were age 64 or older. The presenting visual acuity in all patients was light perception. The blunt injury in each case caused a wound dehiscence at the site of previous cataract extraction. All injuries were associated with uveal prolapse. Secondary surgical intervention was performed when the hemorrhagic choroidal detachments had decreased as demonstrated by echography in the suprachoroidal space, occurring at an average of 14 days after injury. The management consisted of surgical drainage of the choroidal hemorrhage combined with vitrectomy and silicone oil injection. Successful reattachment of the retina was achieved in all cases. Postoperative epiretinal membranes formed in two cases but all were anatomically successful at six months. Final visual acuities varied from 20/70 to 1/200, visual acuity being a function of secondary contusive damage to the retina and choroid. We believe that in eyes sustaining severe blunt injuries resulting in rupture of the globe complicated by massive choroidal hemorrhage and retinal detachment, properly timed external drainage of the choroidal hemorrhage combined with pars plana vitrectomy and silicone oil injection is a useful approach.

Aged↗
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↗
PubMed1987

Intraoperative argon endophotocoagulation for recurrent vitreous hemorrhage after vitrectomy for diabetic retinopathy.

We reviewed the medical records of 103 consecutive cases of vitrectomy performed for complications of diabetic retinopathy to determine if the introduction of argon laser endophotocoagulation had reduced the incidence of recurrent vitreous hemorrhage. Twenty-six eyes (48%) treated with endophotocoagulation and 35 (71%) eyes not receiving laser treatment had a recurrent hemorrhage. Follow-up was shorter for the eyes treated with endophotocoagulation, but a log-rank analysis to allow for this variable confirmed the benefit of laser photocoagulation (P less than .05). The proportion of eyes requiring surgical removal of the hemorrhage was also significantly lower in the group receiving endophotocoagulation (P less than .05). The beneficial effect of intraoperative laser treatment was independent of the amount of preoperative laser treatment, aphakia, and indications for the original vitrectomy surgery.

Argon↗
PubMed1987

Origin of simple glial epiretinal membranes in an animal model.

Severe vitreous hemorrhage was simulated by the injection of 0.2 ml fresh uncoagulated autologous blood into the vitreous cavity of eight rabbits. Four weeks later, hemoglobin released from lysis of the original intravitreal clot had formed a thick layer on the retina. At this stage, many macrophages were conspicuous on the retinal surface and, in addition, in seven of the eight eyes, small cellular membranes were found by scanning electron microscopy. Light and transmission electron microscopy showed these membranes to be derived from accessory glial cells and their progeny. The membranes resembled the simple epiretinal membranes that occur in human eyes.

Animals↗
PubMed1987

Changing attitudes in United States to use of intravitreal silicone.

The use of intravitreal silicone oil injection to separate preretinal membranes from the retinal surface in proliferative vitreoretinopathy (PVR) was pioneered in the United States. The anatomical results obtained were encouraging but complications of cataract, glaucoma and keratopathy frequently occurred. This method was therefore discontinued in the United States once the techniques of pars plana vitrectomy and membrane dissection had been developed. More recently, however, it has become clear that in severe PVR treated by vitrectomy procedures, recurrent traction is almost inevitable and prolonged vitreous substitution is required to limit the associated retinal detachment. Silicone has been selectively re-introduced for this purpose. Improved techniques and oil removal in some cases have reduced the incidence of complications. Insoluble gases have also been widely used in the United States to achieve the same objective but have generally been found to be less effective. The comparative merits of these alternative forms of vitreous substitution remain controversial. A randomized clinical trial is currently being conducted in the United States to address this issue. The trial embodies features of multicenter clinical trials used successfully in other prospective clinical studies. Silicone oil is still used less frequently than in Europe or in Japan for the management of diabetic traction detachment and giant tears.

Attitude of Health Personnel↗
PubMed1986

Aqueous concentrations of fluorouracil after intravitreal injection. Normal, vitrectomized, and silicone-filled eyes.

Treatment of postoperative vitreoretinopathy with combined intravitreal fluorouracil and liquid silicone may result in increased corneal and retinal toxicity. We therefore investigated the movement of carbon 14-labeled fluorouracil from the vitreous into the anterior chamber in normal rabbit eyes and in eyes filled with either balanced salt solution or silicone after vitrectomy and lensectomy, with or without preservation of the anterior capsule. Only 0.56% of intravitreally injected fluorouracil was recovered from the anterior chamber over a four-hour period in normal eyes. This impermeability was partly maintained if the anterior capsule was retained (9.98%), particularly if the eye contained silicone (2.52%). The greatest amount was recovered when both lens capsules were removed (43.7%). Corneal toxicity is most likely to occur in this situation.

Animals↗
PubMed1986

Relative permeability of retina and retinal pigment epithelium to the diffusion of tritiated water from vitreous to choroid.

The movement of intravitreally injected tritiated water from the vitreous to the choroid was accelerated by the removal of intervening retina. Both rate of transfer and peak choroidal levels of the tracer were increased, but the proportion of the intravitreal dose recovered was unaltered. In contrast, the movement of tritiated water after diffuse damage to the retinal pigment epithelium by sodium iodate was similar to that of control eyes. The main resistance to the diffusion of this tracer from the vitreous to the choroid is the retina. The differential permeability of the retina and the retinal pigment epithelium may have a role in normal retinal adhesion.

Animals↗
PubMed1984

Intravitreal expanding gas bubble. A morphologic study in the rabbit eye.

The morphologic changes induced by an expanding bubble of perfluoropropane (C3F8) gas in the vitreous body have been studied in the rabbit eye by dissecting microscopy and scanning and transmission electron microscopy. Initial expansion of the gas displaces water from the vitreous; the remaining vitreous forms a compressed layer on the retinal surface. Subsequent absorption and contraction of the gas bubble is associated with gradual detachment of the compressed vitreous from the retina. Eventually, vitreous detachment is complete, except for residual attachments posteriorly to the medullary rays and anteriorly to the ciliary processes. The plane of vitreous separation is predominantly at the anatomic vitreoretinal junction, although scattered islands of outer cortical vitreous are found on the surface of the retina.

Animals↗