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Biomedical subjects

G W Abrams

Publications and source records attributed to G W Abrams.

84 records · Page 5Linked to original sources
PubMed1982

The results of sulfur hexafluoride gas in vitreous surgery.

Of 101 vitrectomies that used sulfur hexafluoride gas, 42 of 87 eyes followed up for six months had attached retinas and 28 had visual acuities of 6/240 (20/800) or better. Ocular hypertension occurred after 45 of the 101 operations and the incidence of ocular hypertension was significantly higher in eyes that received 100% sulfur hexafluoride than in eyes given lesser concentrations of gas (P less than .05). Twenty-six of 101 eyes developed transient fibrinous exudation. Ocular hypertension was significantly more common in eyes with fibrin than in eyes without fibrin (P = .001). After complicated vitrectomies, 11 eyes developed presumed central retinal artery occlusions and lost light perception on the first postoperative day. Ten of these eyes had increased intraocular pressures. Eyes with severe hemorrhagic complications from vitrectomy were most likely to develop presumed central retinal artery occlusions.

Cataract↗
PubMed1982

Surgical results in ocular trauma involving the posterior segment.

Of 106 eyes with trauma involving the posterior segment, 12 could not be repaired, 74 were treated with vitrectomy, and 20 without vitrectomy. Fifty-five eyes (52%) achieved functional success (defined as a final visual acuity of 6/30 [20/100] or better or as a postoperative improvement in visual acuity from light perception or worse to 6/240 [5/200] or better), 16 (15%) attained anatomic success (attached retinas and generally clear media) but were functional failures, and 35 (33%) were both anatomic and functional failures. The prognosis was better in cases with intraocular foreign bodies and worse in cases with retinal detachments, marked vitreous hemorrhage, and large scleral lacerations. Traumatic involvements of the lens did not appear to affect the prognosis. Prophylactic scleral buckling appeared to lessen the incidence of postoperative retinal detachment. The eyes that underwent vitrectomy within 14 days of the injury had a better final visual outcome than those that underwent later vitrectomy.

Adolescent↗
PubMed1982

Computed tomography and ultrasound in the evaluation of orbital infection and pseudotumor.

Twenty patients with orbital inflammatory processes were examined with high-resolution computed tomography (CT) and 14 of them were also evaluated with ultrasound (US). In eight cases of orbital infection, six abscesses were localized by CT; US contributed no significant additional information. The 12 cases of orbital pseudotumor could be classified into four forms by CT. US added specificity to the CT findings, especially in the tumefactive form. In all eight cases of pseudotumor where US was performed, low-reflective echoes were characteristically seen. In addition, edema in the retrobulbar fascia (four cases) was continuous with fluid along the optic nerve sheath (three cases) and muscle enlargement was identified in six cases. These US features were found to be important in the differential diagnosis of intra-orbital masses.

Abscess↗
PubMed1981

Varix of the vortex ampulla.

In five patients, extreme gaze resulted in the appearance and expansion of a lesion located at the site of a venous vortex ampulla. The dimensions and color of the lesion varied depending upon the direction and duration of gaze. The lesion expanded when the head was positioned below the level of the heart and when a Valsalva maneuver was performed, even when the primary position of gaze was maintained. The lesion rapidly detumesced and disappeared when the head was elevated, digital pressure was exerted on the globe, or gaze was directed elsewhere. Fluorescein angiography confirmed that this tumefaction originated from the venous vortex ampulla. These dynamic features observed ophthalmoscopically and demonstrated by ultrasonography are characteristic of the vortex ampulla varix; the lesion should not be confused with a malignancy.

Aged↗
PubMed1981

The use of intraocular gases. The results of sulfur hexafluoride gas in retinal detachment surgery.

The results of SF6 gas in 69 retinal detachment cases managed with nonvitrectomy techniques are presented. Of 57 cases followed six months, 64.9% were reattached and 61.4% showed stabilization of visual acuity at 20/60 or better or improvement in vision from the preoperative level. Visual and anatomical results were similar between 16 giant tear cases managed with SF6 and a similar previous series from the same institution managed with air. Complications possibly attributable to gas were development or progression of mild cataract changes in 27% of phakic patients and transient elevation of intraocular pressure in 26% of all patients on the first preoperative day. Presumed central retinal artery occlusion occurred in four patients with elevated pressure, with permanent loss of light perception in three diabetic patients. In selected cases where other methods or air will not suffice, SF6 can be useful if used cautiously.

Adolescent↗
PubMed1979

Experimental double-perforating injury of the posterior segment in rabbit eyes: the natural history of intraocular proliferation.

A reproducible model of double perforating injury of the posterior segment of the rabbit eye was developed. Immediately after injury, a viterous condensation was visible between wounds. The scleral exit wound was sealed by fibroblastic proliferation of probable episcleral origin by the fourth day and the entrance similarly by the seventh day. Cellular proliferations originating in the wounds crossed the vitreous cavity following the vitreous injury tract or condensed vitreous to the disc or to the vitreous base. The earliest intraocular proliferations, composed of spindle-shaped, fibroblast-like cells, were seen at day 4. Occasional pigment epithelia were present in and on these proliferations. Other proliferations occurred directly on the retinal surface adjacent to the wounds. The transvitreous proliferations employed the vitreous as a scaffold, while the surface proliferations used the retinal surface for contact guidance.

Animals↗
PubMed1979

Vitrectomy for injury: the effect on intraocular proliferation following perforation of the posterior segment of the rabbit eye.

Perforating injuries were produced in the posterior segments of rabbit eyes. A control group had no surgery; a second group underwent closed vitrectomy immediately after injury; and a third group had closed vitrectomy delayed two weeks following injury. The eyes were then observed for four weeks. Transvitreal proliferation, which was found in each of the control eyes, was effectively prevented in the eyes that underwent immediate vitrectomy. Established transvitreal proliferation was removed and its recurrence prevented by delayed vitrectomy. These results establish the principle that vitreous acts as a scaffold for proliferation. Removal of the vitreous eliminates the structures along which proliferation can occur and thus effectively prevents transvitreal proliferation. Early removal of vitreous in severely injured eyes with vitreous damage is recommended.

Animals↗
PubMed1978

An improved method for practice vitrectomy.

Practice is essential for acquiring the skills necessary for the delicate technique of pars plana vitrectomy. An improved animal model is presented for the beginning surgeon and the assistant to learn basic as well as advanced vitrectomy techniques. A stepwise scheme progressing from simple vitrectomy in the phakic rabbit eye to complicated situations is introduced. Fluorescein staining helps in visualization of the normal vitreous. Double perforating injuries are created to simulate complicated vitreoretinal problems. Methods for learning manipulations with two instruments in the eye are described.

Animals↗
PubMedDate not supplied

Bilateral retinal embolization associated with intralesional corticosteroid injection for capillary hemangioma of infancy.

A 2-month-old female infant underwent intralesional corticosteroid injection for a capillary hemangioma that was causing amblyopia of the right eye from ptosis, globe displacement, and astigmatism. Forty-eight hours after the injection, the infant's parents noted that she was visually inattentive. On examination, she could not fixate or follow with either eye, and an afferent pupillary defect was present in the left eye. Ophthalmoscopy showed scattered areas of intraretinal hemorrhage in the right eye and extensive preretinal and intraretinal hemorrhages in the left eye. Ten months after injection, the hemangioma had greatly regressed, and visual acuity in the right eye was felt to be normal. The left eye had unsteady fixation with a persistent afferent pupillary defect and macular scarring. Retrograde flow of the corticosteroid suspension through the hemangioma's feeder vessels, probably originating from both ophthalmic arteries, is the most likely explanation for this complication.

Betamethasone↗
PubMedDate not supplied

Collagen shield delivery of tissue plasminogen activator: functional and pharmacokinetic studies of anterior segment delivery.

BACKGROUND: Postoperative fibrin formation remains a major complication associated with intraocular surgery, especially after vitreoretinal surgery for proliferative vitreoretinopathy, proliferative diabetic retinopathy, trauma, or endophthalmitis. Tissue plasminogen activator (tPA) has been shown, both in experimental studies and clinical trials, to specifically dissolve formed intraocular fibrin after intracameral or intravitreal injection. We studied collagen shield delivery of tPA to the anterior segment and vitreous of rabbit eyes to evaluate a noninvasive delivery modality. METHODS: Anterior segment fibrin clots were formed in rabbit eyes by injecting citrated rabbit plasma. The tPA hydrated collagen shields, or control shields, were then placed on the rabbit corneas and the extent of fibrin clot was followed. In other rabbit eyes, tPA hydrated collagen shields were placed on the rabbit corneas and an enzyme-linked immunosorbent assay (ELISA) was utilized to determine aqueous, vitreous, and blood levels of tPA over time. RESULTS: Collagen shield tPA delivery shortened the time to fibrin clot lysis by 50% (mean clearance time = 49 +/- 23 hours; P less than .05). ELISA for tPA levels noted measurable vitreous levels by 2 hours after tPA hydrated collagen shield application with a peak at 24 hours. Aqueous tPA levels were not measurable until 18 hours after tPA collagen shield application and peaked at 36 hours. Vitreous tPA levels were greater than aqueous tPA levels at all time points (P less than .05). No evidence of corneal edema or opacification, hemorrhage, or cataract was seen. CONCLUSIONS: These results document the efficacy and safety of tPA delivery to the aqueous and vitreous via a hydrated collagen shield in this animal model.

Absorption↗