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· Background: The success of a retinal prosthesis for patients with outer retinal degeneration (ORD) depends on the ability to electrically stimulate retinal cells other than photoreceptors. Experiments were undertaken in human volunteers to ascertain whether electrical stimulation of cells other than photoreceptors will result in the perception of light. · Methods: In two subjects, two areas of laser damage (argon green and krypton red) were created in an eye scheduled for exenteration due to recurrent cancer near the eye. In the operating room prior to exenteration, under local anesthesia, a hand-held stimulating device was inserted via the pars plana and positioned over the damaged areas and normal retina. Subjects’ psychophysical responses to electrical stimulation were recorded. · Results: In both subjects, electrical stimulation produced the following perceptions. Normal retina: dark oval (subject 1), dark half-moon (subject 2); krypton red laser-treated retina: small, white light (both subjects); argon green laser-treated retina: thin thread (subject 1), thin hook (subject 2). Histologic evaluation of the krypton red-treated retina showed damage confined to the outer retinal layers, while the argon green-treated area evinced damage to both the outer and the inner nuclear layers · Conclusion: The perception produced by electrical stimulation was dependent on the retinal cells present. Electrical stimulation of the krypton red-ablated area best simulated the electrically elicited visual perceptions of our blind, ORD patients, suggesting that the site of stimulation in blind patients is the inner retinal neurons.

Rubeosis iridis was produced in cynomolgus monkeys by subjecting their eyes to severe surgically induced hypotony. New vessels on the iris showed characteristic fenestrations of endothelial cell walls as well as mitotic activity.

This paper describes transfer of skills obtained from training with the EyeSI virtual reality simulator of ophthalmic surgery to real-life surgical performance. Skills in real-life phacoemulsification surgery were assessed by systematic blinded evaluation of surgical videos based on the OSACCS system. Nineteen Danish cataract surgeons with varying clinical experience levels had their cataract surgery skills evaluated before and after completing a standardized mastery learning program on the EyeSI. It was found that transfer of skills could be demonstrated only for surgeons with a real-life experience of less than 75 completed, independent cases. We could not demonstrate transfer of skills from the EyeSI cataract module to the EyeSI vitreoretinal module, so each subspecialty seems to require specific training. Finally, the discriminative power of EyeSI simulation between emerging surgeons and experts was found to reside only in the first training sessions. The EyeSI simulator in its current state of development, and our implementation of it, seems to require further development before it can be used as a tool to select residents for surgical training and to re-certify more senior surgeons.

In a prospective clinical trial, the effect of systemic steroids on the incidence and severity of retinal fibrosis following retinal detachment surgery was tested against placebo. Several grades of retinal fibrosis of various degrees of severity were defined prior to the study. The maximum postoperative incidence of eyes with any signs of retinal fibrosis was 65% (75.4% in the placebo group, 63.3% in the steroid group). A set of fibrosis criteria was identified that had a tendency to respond to systemic steroids with a statistical significance increasing with time. The majority of these steroid-responsive criteria was of a mild degree and located at the posterior pole. The mean visual acuity was significantly lower in eyes with retinal fibrosis. The effect of systemic steroids on retinal fibrosis tested under clinical conditions was considerably weaker than that known from experimental conditions with intravitreal injections of triamcinolone acetonide.

Pairwise comparisons of peripapillary crescents and haloes were performed for 56 eyes of 28 patients with early or moderate unilateral capsular glaucoma and no signs of exfoliation in the contralateral eye. The eyes differed highly significantly in rim area, rim/disc area ratio, cup area, and cup volume. They did not differ in disc areas, scleral ring areas, or size of peripapillary crescents. In the nonglaucomatous and glaucomatous eyes a significant correlation existed between the intraocular pressure (IOP) and the area of peripapillary atrophy. The area of peripapillary atrophy was significantly correlated with the damage to the glaucomatous optic nerve head. We concluded that the area of peripapillary atrophy is largely an inborn feature, and that nerve fiber loss can occur without differences in the peripapillary tissues. Nevertheless, an IOP-induced change in the retinal pigment epithelium cannot be ruled out.

Es wird ein Celloidin-Paraffin-Einbettungsverfahren für die histologische Bearbeitung von enukleierten Augen mitgeteilt. Diese neue Methode ermöglicht die Herstellung untersuchungsfertiger Schnitte innerhalb von weniger als 3 Wochen. Diese Schnitte besitzen dieselbe Güte wie bisherige Celloidinschnitte nach einer Vorbereitungszeit von 4–6 Monaten.