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Biomedical subjects

H L Friedberg

Publications and source records attributed to H L Friedberg.

6 recordsLinked to original sources

Comparison of the unwanted optical images produced by 6 mm and 7 mm intraocular lenses.

Unwanted optical images are noticed by a surprisingly large number of patients following cataract extraction with implantation of posterior chamber intraocular lenses (IOLs). These images are caused by the positioning holes, lens edge, or laser ridge. We studied 550 eyes in which one of seven different IOLs was inserted. The IOLs varied in optic diameter, the presence or absence of positioning holes or a laser ridge, the use of partial depth holes or placement of positioning holes in tabs outside the optical zone. We determined that unwanted optical images could practically be eliminated by using a 7 mm optic without positioning holes. This study also demonstrated that partial depth holes offer no advantage over full thickness holes for reducing unwanted optical images and that positioning holes, even on a 7 mm optic, produce a significant number of complaints.

Equipment Design↗

Brain stem anesthesia after retrobulbar block.

Presented is a series of eight patients in whom neurologic sequelae developed after retrobulbar anesthesia. All patients demonstrated blockade of one or more cranial nerves and six progressed to apnea, requiring intubation and mechanical ventilation. Neurologic findings included amaurosis in the contralateral eye (5 patients), nonreactive pupil in the contralateral eye (6 patients), ductional defects (2 patients), and dysphagia (4 patients). In all cases, these findings resolved in 2 to 12 hours. In patients who progressed to apnea, spontaneous respiration resumed within 30 to 60 minutes. These findings are particularly significant in light of recent decisions to reduce anesthesia coverage for cataract surgery in some regions.

Adult↗

Contralateral amaurosis after retrobulbar injection.

Contralateral amaurosis after retrobulbar injection of local anesthetic agents occurred in two patients, a 64-year-old woman and a 57-year-old man. The amaurosis resulted from migration of the anesthetic agents to the optic chiasm and contralateral optic nerve via the subarachnoid space. In both cases visual acuity returned to preoperative levels within 90 minutes. A modified technique in which patients look straight ahead or slightly downward and outward during retrobulbar injection, as opposed to the traditional upward and inward positioning of the globe, avoids inadvertent piercing of the sheaths of the optic nerve and injection of substances into the subarachnoid space.

Akathisia, Drug-Induced↗