PubMed Health⌕ Search

Biomedical subjects

G W Abrams

Publications and source records attributed to G W Abrams.

At least 19 recordsLinked to original sources
PubMed1992

Macular phototoxicity caused by fiberoptic endoillumination during pars plana vitrectomy.

Three cases of retinal phototoxicity were caused by light from the endoilluminator used in vitrectomy. Preoperative clinical examination, color photography, and fluorescein angiography in all three cases failed to disclose retinal pigment epithelial changes. Postoperative clinical findings, photographs, and fluorescein angiograms are highly suggestive of the presence of retinal phototoxicity. The characteristics of these lesions and surgical conditions implicate the endoilluminator as the source of photic injury. The macular lesions were noted within one week of the surgical procedure, measured between 2 and 5 disk diameters in size, involved the fovea in two eyes, and resulted in marked decrease in visual acuity in two of three eyes, with persistence in one eye. Initially, whitening of the outer retina was present, but was replaced by pigmentary mottling at the level of the retinal pigment epithelium within a few weeks. Preventive measures to avoid macular phototoxicity associated with vitrectomy are discussed.

Adult↗
PubMed1992

Combined phacoemulsification, pars plana vitrectomy, and posterior chamber intraocular lens insertion.

Eighteen eyes with coexisting cataract and vitreoretinal disease underwent combined phacoemulsification, pars plana vitrectomy, and posterior chamber lens implantation. Preoperative vitreoretinal disease included nonclearing vitreous hemorrhage (eight eyes), vitreous hemorrhage and tractional retinal detachment (three eyes), tractional retinal detachment (one eye), epiretinal membranes (three eyes), peripheral uveitis (two eyes), and a retained intraocular metallic foreign body (one eye). Postoperative visual acuity improved in each case; 14 eyes achieved visual acuity between 20/20 and 20/80 during an average postoperative period of 11 months (range, 3 to 39 months). Perioperative complications included an iatrogenic retinal break (one eye) and pupillary block glaucoma (one eye). Four eyes required YAG laser capsulotomy postoperatively. Phacoemulsification did not interfere with corneal clarity, allowed water-tight wound closure during vitrectomy, and preserved the capsular bag, allowing endocapsular fixation of the posterior chamber lens. Combining phacoemulsification, posterior chamber lens implantation, and pars plana vitrectomy allows rapid visual rehabilitation and functional unaided vision in these eyes.

Adult↗
PubMed1992

Vitrectomy for diabetic macular traction and edema associated with posterior hyaloidal traction.

Pars plana vitrectomy with separation of the posterior hyaloid was performed in 10 eyes with diabetic macular edema and traction associated with a thickened and taut premacular posterior hyaloid. Nine of the 10 eyes had previous macular photocoagulation. Preoperative fluorescein angiography showed a deep and diffuse pattern of leakage in the macula. Intraoperatively, the attached and thickened posterior hyaloid was lifted and separated from the retina. Postoperatively, vision improved in nine eyes. The macular traction and edema resolved in eight eyes and decreased in two. Complications included a vitreous hemorrhage, a rhegmatogenous retinal detachment, cataract formation, and a mild epimacular membrane, each occurring in one eye. Vitreous surgery can improve the visual prognosis of some eyes with diabetic macular traction and edema associated with a thickened and taut posterior hyaloid.

Adult↗
PubMed1992

The lowest effective dose of tissue plasminogen activator for fibrinolysis of postvitrectomy fibrin.

Tissue plasminogen activator (tPA) has been shown to be effective at a dose of 25 micrograms in the treatment of severe postvitrectomy fibrin. However, a recent report based on an animal model indicates that retinal toxicity may occur at doses as low as 25 micrograms. This study uses a low dose (1.5 micrograms to 3 micrograms) of tPA for 34 injections in 26 eyes, and determines the lowest effective dose to be between 1.5 and 3 micrograms. Complete fibrinolysis was achieved in all 28 eyes in which 3 micrograms of tPA was administered within 10 days of vitrectomy, whereas partial fibrinolysis was achieved in eyes treated with 3 micrograms of tPA 27 days and 82 days after vitrectomy. Complete fibrinolysis occurred in only 1 of 4 eyes that receive 1.5 micrograms of tPA. A dose of 3 micrograms of tPA is recommended for treatment of severe fibrin after vitrectomy, as it has a wider margin of safety than do higher doses.

Adolescent↗
PubMed1991

Causes of failure after initial vitreoretinal surgery for severe proliferative vitreoretinopathy.

We performed initial vitreoretinal surgery on 81 eyes with rhegmatogenous retinal detachments complicated by severe proliferative vitreoretinopathy. Of 81 eyes, 68 (84%) had undergone previous scleral buckling. We performed vitreous base dissection on all 18 eyes (22%) that had anterior proliferative vitreoretinopathy. With one vitreoretinal operation, 66 of 81 eyes (81%) remained totally reattached. The main cause of initial anatomic failure and reoperation was either new or recurrent proliferation at the vitreous base. With additional vitreoretinal surgery and after a mean follow-up period of 19 months, 73 of 81 retinas (90%) were totally reattached. The final causes of anatomic failure were anterior proliferative vitreoretinopathy and proliferation from relaxing retinotomies. Of the 73 successfully reattached eyes, 62 (85%) had postoperative visual acuity of 5/200 or better.

Female↗
PubMed1991

A technique for facilitated visualization and dissection of the vitreous base, pars plana, and pars plicata.

We describe a technique to facilitate visualization of the vitreous base, pars plana, and pars plicata during vitreous surgery. This technique takes advantage of an externally applied fiberoptic light source coupled with scleral depression to enable direct viewing of the ciliary processes and anterior vitreous base. No special instrumentation or alteration in pars plana vitrectomy techniques is required. We have used this technique to enhance anterior dissection during vitrectomy surgery in the aphakic and pseudophakic eye associated with proliferative vitreoretinopathy, diabetic retinopathy, epithelial down-growth syndromes, and postvitrectomy fibrin formation.

Eye Diseases↗
PubMed1991

Outpatient fluid-air exchange for severe postvitrectomy diabetic vitreous hemorrhage. Long-term results and complications.

An alternative treatment to repeat vitrectomy in postvitrectomy diabetic vitreous hemorrhage (PDVH) is outpatient fluid-air exchange, but the long-term visual results of this procedure are not known. Between January 1986 and April 1989, a pars plana air-pump technique was used to perform outpatient fluid-air exchange in 20 eyes of 17 patients (17 phakic eyes) within 8 weeks of onset of PDVH. A mean follow-up interval of 78 weeks was obtained. Preoperative vitreous hemorrhage was severe enough to obscure all fundus detail (17 eyes) or produce erythroclastic glaucoma (three eyes). Initial visual acuity was hand motions or light perception in 19 eyes and improved to a median visual acuity of 20/300 soon after resolution of the intraocular air bubble. Early complications included postoperative fibrin formation (one eye) and early postoperative intraocular pressure elevation (two eyes). Recurrent vitreous hemorrhage required repeated fluid-air exchanges in seven eyes. Long-term complications included worsening of posterior subcapsular cataract (10 of 17 phakic eyes, 59%), for which cataract extraction was required in five eyes (29%). Fluid-air exchange appeared to exacerbate cataract formation, justifying a period of observation for PDVH. However, it appeared to be a low-risk alternative to repeat vitrectomy, allowing rapid visual recovery from severe PDVH.

Adult↗
PubMed1990

Risk factors for postvitrectomy fibrin formation.

We prospectively studied 194 patients undergoing vitrectomy between July 1988 and April 1989 to determine the incidence of postvitrectomy intraocular fibrin formation and the association of a variety of preoperative and intraoperative variables with the formation of severe postvitrectomy fibrin. Overall, 62 (32%) patients developed postvitrectomy fibrin; 25 (13%) had mild fibrin formation, 13 (6.5%) had moderate fibrin formation, and 24 (12.4%) had severe fibrin formation. By logistic multivariate analysis, preoperative factors that were independently predictive of severe fibrin formation included severe flare (P = .004), the presence of a previously placed scleral buckle (P = .001), and poor preoperative visual acuity (P = .007). Anterior epiretinal membrane dissection was the only intraoperative factor that was independently associated with an increased fibrin risk (P = .0003). A risk score derived from the multivariate analysis effectively categorized patients according to their likelihood of developing severe postvitrectomy fibrin. Results of this study may be useful in designing prophylactic interventions to decrease postvitrectomy fibrin formation.

Adult↗
PubMed1990

Rebleeding in experimental traumatic hyphema treated with intraocular tissue plasminogen activator.

Tissue plasminogen activator has recently been shown to enhance the clearance of experimental nontraumatic hyphema in animals. However, hyphema in human eyes usually results from ocular trauma, and rebleeding is a serious complication. Hemorrhage is also a potential complication of fibrinolytic therapy. We assessed the incidence of rebleeding in an animal model of surgically induced traumatic hyphema after intracameral injection of tissue plasminogen activator (25 micrograms) or physiological saline. Eight eyes were each treated with tissue plasminogen activator or physiological saline at 10 minutes, 24 hours, 48 hours, or 72 hours after injury. Controls were 8 eyes with hyphema but no intracameral injection. No eyes treated with physiological saline (total, 32 eyes) or control eyes rebled. In contrast, the incidence of rebleeding from the injury site in eyes treated with tissue plasminogen activator was 88% (7/8) at 10 minutes, 75% (6/8) at 24 hours, 50% (4/8) at 48 hours, and 0% (0/8) at 72 hours after injury. Treatment of traumatic hyphema with tissue plasminogen activator prior to healing of damaged vascular endothelium may contribute to rebleeding.

Animals↗
PubMed1990

Combined phacoemulsification and pars plana vitrectomy.

Combined phacoemulsification and pars plana vitrectomy were performed in eight eyes with cataract and vitreoretinal disease. Six eyes had tractional retinal detachment and/or nonclearing vitreous hemorrhage, one eye had a retained metallic intraocular foreign body, and one eye had a traumatic retinal detachment. In six eyes, a posterior chamber lens implant was placed in the capsular bag. Postoperative visual acuity improved in each case and ranged between 20/15 and 6/200. There were no perioperative complications, and the posterior chamber lens implant appeared well tolerated during an average follow-up interval of 8 months (range, 3 to 30 months). This technique allows endocapsular fixation of a posterior chamber lens and provides rapid visual rehabilitation with a single operation.

Adult↗
PubMed1990

Relaxing retinotomies and retinectomies. Surgical results and predictors of visual outcome.

Functional and anatomic success after relaxing retinotomy may be limited by recurrent retinal detachment or severe hypotony. Fifty-four consecutive eyes undergoing relaxing retinotomy for proliferative vitreoretinopathy (42 eyes) and trauma (12 eyes) were analyzed to determine whether perioperative factors, including size and location of the retinotomy, influenced visual or anatomic outcome. After 6 months' minimum follow-up, anatomic success (retina attached posterior to buckle and an intraocular pressure of 3 mm Hg or more) was achieved in 35 eyes (64%). Functional success (visual acuity of 5/200 or better) was achieved in 14 eyes (26%). Factors predicting functional success by stepwise logistic regression analysis included a preoperative visual acuity of hand motions or better and location of the retinotomy in the superior four clock hours of the fundus. Causes of anatomic failure included proliferative vitreoretinopathy (11 eyes) and severe hypotony or phthisis (8 eyes). Superior location of the retinotomy and visual acuity of hand motions or better favorably influenced visual outcome after relaxing retinotomy.

Adolescent↗
PubMed1990

A new self-sealing needle for iris suture fixation.

We adapted a 27-gauge, 0.75-in needle for the placement of iris fixation sutures. The needle requires neither the formation of a paracentesis nor a sclerotomy site. Additionally, the self-sealing nature of the needle tract eliminates the need for closure of the entry site. We have found this instrument to be helpful in the rapid, atraumatic placement of iris fixation sutures.

Equipment Design↗
PubMed1990

Management of traumatic hemorrhagic retinal detachment with pars plana vitrectomy.

Traumatic hemorrhagic retinal detachment may prevent successful visual rehabilitation of eyes with severe posterior segment injury. We managed 19 consecutive cases of traumatic hemorrhagic retinal detachment with pars plana vitrectomy, scleral buckling, and fluid-gas exchange, with or without internal drainage of subretinal hemorrhage. We based our approach on the amount of subretinal hemorrhage present and the location of associated retinal breaks. Internal drainage of subretinal hemorrhage was performed in 16 eyes to allow adequate retinopexy to hemorrhagically elevated retinal breaks (9 eyes), to remove massive subretinal hemorrhage (4 eyes), and to allow intraoperative reattachment when the retina exhibited bullous retinal detachment (3 eyes). Overall, with a minimum of 6 months of follow-up, anatomic reattachment was achieved in 13 (68%) of 19 eyes, and functional success (visual acuity 5/200 or better) was achieved in 6 (32%) of 19 eyes. Anatomic failure resulted from proliferative vitreoretinopathy (4 eyes) and globe atrophy (2 eyes). Drainage of subretinal blood appeared to be beneficial for hemorrhagically elevated retinal tears to allow adequate retinopexy and may help to accomplish long-term anatomic attachment in eyes with massive subretinal hemorrhage or bullous retinal detachment.

Adolescent↗
PubMed1990

A two-stage technique for intraoperative fluid-gas exchange following pars plana vitrectomy.

We describe herein a two-stage technique of intraoperative fluid-gas exchange following pars plana vitrectomy. The first stage is a complete fluid-air exchange using an air pump and intraocular linear suction. The air pump then maintains the intraocular pressure at the desired level during adjunctive procedures, such as laser endophotocoagulation. The second stage is an air-gas mixture exchange in which the desired gas, premixed in air to the desired final intraocular concentration, is manually flushed through the eye. This technique allows the attainment of an accurate concentration of intraocular gas if the air-gas mixture exchange is complete. In vitro and in vivo experiments in aphakic human eyes demonstrated that an effectively complete air-gas mixture exchange occurs with a 25-mL flush volume. This result compares favorably with the theoretical prediction derived from a "pharmacokinetic approximation" equation.

Body Fluids↗
PubMed1990

Tissue plasminogen activator for postvitrectomy fibrin formation.

The authors injected 25 micrograms of recombinant tissue plasminogen activator (tPA) into the anterior chamber or vitreous cavity of 23 eyes of 22 patients with severe intraocular fibrin formation that developed after vitrectomy surgery for complicated cases of proliferative vitreoretinopathy (PVR) (13 eyes), diabetic traction retinal detachment (TRD) (7 eyes), or endophthalmitis (3 eyes). Tissue plasminogen activator injected an average (+/- standard deviation) of 73 +/- 63 hours after vitrectomy surgery resulted in complete fibrinolysis in 21 of 23 eyes and partial fibrinolysis in one eye. The mean time to fibrin resolution was 3.0 +/- 1.0 hours. Four eyes required repeat tPA injection for recurrent fibrin formation; repeat injection resulted in complete fibrinolysis in each case. The mean follow-up duration after tPA administration was 6 months. At the final follow-up examination, the retina was totally attached in 18 of 23 eyes and was partially attached in 2. Visual acuity improved in 12 eyes (52%); it was at least 20/400 in 8. Complications of tPA injection included hyphema (2 patients) and corneal stromal thickening (2 patients). Mild, transient, periocular pain that was easily managed with non-narcotic analgesia developed in three patients.

Adolescent↗