[Crisis management strategies of hospitals during the pandemic].

Background: The SARS-CoV‑2 pandemic has led worldwide to substantial limitations in healthcare systems. This article describes the recent developments and measures from March through May 2020, which have contributed to the maintenance of ophthalmological care at in-patient departments of ophthalmology.

Methods: PubMed literature search, own data, interhospital survey.

An optically powered single-channel stimulation implant as test system for chronic biocompatibility and biostability of miniaturized retinal vision prostheses.

A microsystem based microimplant with an optically powered single-channel stimulator was designed and developed as test system for an epi-retinal vision implant. Biostability of the hybrid assembly and the encapsulation materials were evaluated in pilot experiments in chronic implantations in a cat animal model. The implant was fabricated on a flexible polyimide substrate with integrated platinum electrode, interconnection lines, and contact pads for hybrid integration of electronic components.

Intraocular fluid-air exchange reduces retinal ganglion cell activity.

Aim: To demonstrate the influence of intraocular fluid-air exchange on retinal ganglion cell activity.

Methods: In two cats lensectomy and vitrectomy were performed in a two-step approach 2 weeks prior to recording experiments. To measure retinal activity, up to two fiber microelectrodes were inserted via a scleral port.

Visual resolution with retinal implants estimated from recordings in cat visual cortex.

We investigated cortical responses to electrical stimulation of the retina using epi- and sub-retinal electrodes of 20-100 microm diameter. Temporal and spatial resolutions were assessed by recordings from the visual cortex with arrays of microelectrodes and optical imaging. The estimated resolutions were approximately 40 ms and approximately 1 degrees of visual angle.

Retino-cortical information transmission achievable with a retina implant.

Blind subjects with photoreceptor degeneration perceive phosphenes when their intact retinal ganglion cells are stimulated electrically. Is this approach suitable for transmitting enough information to the visual cortex for partially restoring vision? We stimulated the retina of anesthetized cats electrically and visually while recording the responses in the visual cortex. Transmission of retino-cortical information T was quantified by information theory.

Double-blind, placebo-controlled trial of octreotide long-acting repeatable (LAR) in thyroid-associated ophthalmopathy.

Several uncontrolled studies suggest octreotide is beneficial in thyroid-associated ophthalmopathy (TAO); however, the natural tendency of TAO to improve mandates randomized, controlled trials. We report results of a double-blind, placebo-controlled trial of octreotide long-acting repeatable (LAR). Fifty euthyroid patients (11 males, 39 females; age 22-74 yr, median 50 yr) with active TAO [clinical activity score (CAS) > or =3, NOSPECS (no signs or symptoms; only signs, no symptoms; signs only; proptosis; eye muscle involvement; corneal involvement; sight visual acuity reduction) 2a-5a] of median duration 0.

Subretinal implantation and testing of polyimide film electrodes in cats.

Background: Progress in the field of microelectronics has led to the development of visual prostheses for the treatment of blinding diseases. One concept under investigation is an electronic subretinal prosthesis to replace the function of lost photoreceptors in degenerative diseases, such as retinitis pigmentosa.

Methods: In the subretinal prosthesis design concept, an array of stimulation electrodes is placed in the subretinal space.

Towards the cortical representation of form and motion stimuli generated by a retina implant.

Background: A retina implant for restoring basic visual perception in patients who are blind due to photoreceptor loss should not only evoke focal phosphenes at high resolution, but should also generate cortical representations of form and motion. We are currently exploring these potential capabilities in anaesthetised cats.

Methods: Fibre electrodes were inserted through a small scleral incision onto the retinal surface for stimulation.

Activation zones in cat visual cortex evoked by electrical retina stimulation.

Background: A retina implant for restoring simple basic visual perception in patients who are blind due to photoreceptor loss requires optimisation of stimulation parameters for obtaining high spatio-temporal resolution. We developed effective low-power epi-retinal stimulation and intracortical recording in semichronically prepared cats.

Methods: Individually driveable fibre electrodes were inserted through a small scleral incision and positioned at the area centralis.

Tissue plasminogen activator plus gas injection in patients with subretinal hemorrhage caused by age-related macular degeneration: predictive variables for visual outcome.

Purpose: To assess factors predicting final visual outcome after displacement of subretinal hemorrhage (SRH) by intravitreally injected tissue plasminogen activator (TPA) and gas in patients suffering from age-related macular degeneration (ARMD).

Methods: We evaluated retrospectively the records of 67 patients (32 men, 35 women, mean age 77.2 years) suffering from SRH caused by ARMD who underwent TPA and gas injection between April 1996 and October 2000.

[The predictive value of a classification for proliferative diabetic vitreoretinopathy].

Background: Kroll's classification of proliferative diabetic vitreoretinopathy (PDVR) defines stage A (vitreoretinal proliferations without retinal detachment), stage B (partially detached retina not involving the macula), stage C (partially detached macula) and stage D (completely detached macula). The purpose of this study was to analyse the prognostic value of Kroll's classification in respect of the postoperative results of vitreoretinal surgery based on our group of patients.

Patients And Methods: The charts of 563 patients who underwent vitrectomy because of PDVR between 1990 and 1997 were examined retrospectively.