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Silicon-micromachined retinal tacks were developed for the fixation of the epiretinal-type retina-stimulating microelectrode array. Silicon retinal tacks were fabricated by using the silicon on insulator (SOI) process, a method of releasing silicon structures in a SOI wafer. The dimensions of the retinal tack were substantially smaller than those of the conventional titanium tack, at 1.5 mm long, 150 μm wide, and 150 μm thick. To enhance the durability and biocompatibility of the retinal tack, 3 μm-thick parylene film was uniformly deposited on the entire surfaces. Short-term evaluation of the durability of the silicon retinal tack in vivo showed acceptable biocompatibility and firm fixation of the microelectrode array onto the retina.

The cell orientation and attachment were controlled by a submicron-scale topographical cue. For achieving the submicron undulation of surface topography, the laser holography on a photo-responsive azobenzene copolymer layer has been employed to produce surface relief grating (SRG) which has a regular sinusoidal shape. Cultured human astrocytes (HA) were preferentially attached onto the SRG surface and highly elongated along the SRG direction. This topographical control scheme would be very efficient to control the cell growth for cellular engineering applications and to understand the interactions of the cells with a submicron-scale topographical surface.

Artificial retina is aimed for the stimulation of remained retinal neurons in the patient with degenerated photoreceptors. Microelectrode arrays have been developed for this as a part of stimulator. To minimize the damage during ophthalmic surgery and to get better contact to retina, flexible polyimide, which can be fabricated based on semiconductor manufacturing, was selected as the substrate material. In vitro biocompatibility of polyimide microelectrode array (MEA) was tested by co-culture with human retinal pigment epithelial cells (RPE). In vivo biocompatibility was tested in the rabbit eyes. The polyimide MEA showed good affinity to human RPE and did no harmful effect. It also showed very good stability and safety in rabbit eyes by 12 weeks.

Purpose To assess the anatomic and functional characteristics in a Korean family with spinocerebellar ataxia type 7-associated atrophic maculopathy. Design Observational case report. Methods Three patients in a family underwent funduscopic examination, fluorescein angiogram, full-field electroretinogram (ERG), electro-oculogram, and optical coherence tomography (OCT). Macular functions were assessed using multifocal ERG and scanning laser ophthalmoscope (SLO) microperimetry. Results Both eyes showed bull’s eye configuration and cone-rod dystrophy phenotype. OCT revealed that retinal thinning extended outside the visibly atrophic lesions. Multifocal ERG demonstrated that amplitudes from the six ring segments were reduced in a centrifugal pattern. SLO microperimetry showed that fixations were unstable and shifted superior to the atrophic lesions. The areas of functional deficits were greater than those of anatomic deficits. Conclusions Macular functions were severely depressed in atrophic maculopathy associated with spinocerebellar ataxia type 7 in both the visibly atrophic areas and the areas without visible atrophy in a centrifugal pattern.

To identify characteristics measured by optical coherence tomography (OCT) that are correlated with visual outcome after epiretinal membrane (ERM) removal by pars plana vitrectomy (PPV).Interventional, prospective, randomized case series.One hundred and one eyes of 101 patients with idiopathic ERM underwent PPV for ERM removal. Ophthalmic evaluations included best-corrected visual acuity (BCVA) and Stratus OCT preoperatively at 3 and 6 months postoperatively. Relations between three OCT features including integrity of junction between inner and outer segments of photoreceptors (IS/OS junction), macular thickness, foveal contour and the three visual acuity parameters such as preoperative BCVAs, postoperative BCVAs, and the differences between preoperative and postoperative BCVAs (BCVA differences) were evaluated with respect to time.Eyes with disruption of IS/OS junction had significantly lower postoperative BCVA and BCVA differences than those without disruption (P.0001, respectively). "Same" (increment or decrement of BCVA up to 1 Snellen line) and "Better" (visual increment of at least 2 Snellen lines) BCVA outcome groups were significantly different with respect to the status of IS/OS junction (P.005). An increase in the proportion of eyes with photoreceptor disruption was observed at 3 months postoperatively, and this proportion was maintained afterward. Preoperative macular thicknesses showed a positive correlation with BCVA differences, and postoperative macular thicknesses negatively correlated with postoperative BCVA (r0.25; P.05, respectively). Thickness difference and foveal contour were not correlated with the three parameters of visual outcome (P.05, respectively).Photoreceptor disruption detected by OCT was found to be a predictor of poor visual outcome in eyes with idiopathic ERM, and it was found that this disruption may be irreversible. Thus, early membrane removals may beneficially prevent further progression of photoreceptor damage in ERM patients with photoreceptor disruption.