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Biomedical subjects

G W Weinstein

Publications and source records attributed to G W Weinstein.

At least 55 records · Page 3Linked to original sources
PubMed1981

Computerized tomographic scan findings in facial fractures associated with blindness.

A retrospective study of 379 consecutive patients who underwent operative repair of facial fractures at the West Virginia University Medical Center was carried out. Blindness developed in at least one eye in 21 (6%) of the 379 patients studied. Le Fort II and Le Fort III fractures, frontal bone and frontal sinus fractures, severe fractures of the zygoma, and fractures of the orbital floor were associated with fractures of the lesser sphenoid wing and optic canal in 5 of the patients studied. These 5 patients had indirect optic nerve injuries, as determined by CT scan and clinical criteria, which included visual loss with afferent pupillary defect and an otherwise normal ophthalmologic examination. In addition, one other patient who was not one of the 379 patients who underwent operative repair gradually developed ipsilateral blindness as a result of indirect optic nerve injury following minimal frontal bone trauma without a fracture. The usual mechanism of injury was trauma at the level of the orbital roof. The principal findings on CT scan were those of fracture of the lesser sphenoid wing and subdural hematoma of the optic nerve sheath. The association between sphenoethmoid sinus hemorrhage and fracture of the optic canal (31%) in cases of facial trauma has been presented. The indications for optic nerve decompression have been discussed. To the authors' knowledge, there is no previous report of an optic canal fracture as diagnosed by computerized tomography in the literature.

Adolescent↗
PubMed1980

Safe and effective intraocular lens implantation in a teaching environment.

Intraocular lens implantation was performed as part of a residency training program over a period of two years. Both residents and faculty performed surgery, using anterior chamber angle-fixated (Tennant-Choyce) and iris-fixated (Worst Medallion) lenses. Data with at least three months of follow-up were collected on 148 patients. Of these, visual acuity of 20/40 or better was achieved in 65% (68% of resident cases, 61% of faculty cases). Cystoid macular edema was the most common complication (13% of all cases) occurring nearly twice as often in resident cases. Based on the above, the authors conclude that it is justified to continue a program of lens implantation in a training environment.

Aged↗
PubMed1979

An en bloc technique for the resection of anterior uveal tumors.

We modified trabeculo-iridocyclosclerectomy in a technique for en bloc excision of anterior uveal tumor. A trabeculectomy-type of approach was used, which allowed excision of a rectangular block of sclera, cornea, and trabeculum with attached uveal tissue containing the tumor.

Adult↗
PubMed1978

Photocoagulation of the fovea.

The visual outcome, histopathology, and electrodiagnostic tests of a man with a malignant melanoma of the choroid who received foveal argon laser photocoagulation prior to enucleatiion are described. The low intensity foveal burn destroyed only the outer retinal layers and spared the inner retina. Vision was reduced to 20/50 immediately, but recovered to 20/30 after one day. The visually-evoked-potential (VEP) was altered in both amplitude and waveform by the small foveal burn. A patient with solar retinopathy and permanent visual loss demonstrated only waveform changes on VEP testing. Monkeys with mild experimental foveal burns demonstrated outer layer retinal damage and waveform changes on VEP testing. The retinal energy density threshold for argon laser photocoagulation of the fovea is lower than 0.13 joules/mm.2.

Animals↗
PubMed1978

Clinical aspects of the visually evoked potential.

The visually evoked potential (VEP) was studied in normal and abnormal human subjects, and in Rhesus monkeys. A relatively simple protocol for clinical VEP testing is described. The monkeys showed similar but smaller VEP responses compared to those obtained from human subjects. Central, but not paracentral or peripheral photocoagulation retinal lesions were associated with VEP abnormalities. The second, smaller wave of the response complex to 10 Hz flash stimuli corresponds to the primary evoked response, and is closely related to visual acuity. It was possible to recognize visually this VEP waveform and subjectively interpret the record correctly in 85% of eyes with regard to visual acuity. Therefore, the clinician can "read" the VEP record in response to non-patterned flash stimuli. This test was further validated in a series of patients with opacities of the ocular media. VEP promises to become a procedure of diagnostic and prognostic value in ophthalmology.

Adolescent↗
PubMed1977

Clinical aspects of the visually evoked potential.

The visually evoked potential (VEP) was studied in normal and abnormal human subjects, and in Rhesus monkeys with central, paracentral, and peripheral photocoagulation lesions. A relatively simple protocol for clinical VEP testing is described. The monkeys showed similar VEP responses but these were smaller in amplitude than those obtained from human subjects. Central, but not paracentral or peripheral retinal lesions were associated with VEP abnormalities. For both monkey and human subjects, some variability of responses between normal and subjects was noted. Generally, there are differences in VEP responses obtained from the affected eye of abnormal subjects who had one eye which could serve as a control, as compared to responses from the normal eye. In these subjects as well as in subjects with two abnormal eyes, computer analysis of digitized VEP data from 10 Hz stimulus responses was performed. Fourier transformation analyses showed abnormalities which could be detected easily by evaluating the pattern of the amplitudes of the fundamental and first three harmonics. With this technique, it was possible to group correctly normal VEP's with eyes with normal visual acuity (greater than or equal to 20/30 or 0.67), and abnormal VEP's with eyes with poor visual acuity (less than 20/30 or 0.67) in 72% of cases. Analysis of the data obtained with 1 Hz and 10 Hz stimulation suggests that the components of the VEP related to visual acuity occur within the first 60-100 msec of the response, corresponding to the primary evoked response of Chiganek. The second, smaller wave of the response complex to 10 Hz flash stimuli corresponds to the primary evoked response, and is closely related to visual acuity. This was further supported in another series in which the digitized data was filtered around the stimulating frequency. It was possible to recognize visually this VEP waveform and subjectively interpret the record correctly in 85% of eyes with regard to visual acuity. Therefore, the clinician can "read" the VEP record in response to nonpatterned flash stimuli. This test was further validated in a series of patients with opacities of the ocular media, such as cataract, corneal scarring, and vitreous hemorrhage. VEP promises to become a procedure of diagnostic and prognostic value in ophthalmology.

Adolescent↗