The EPIRET3 system can be successfully implanted and explanted in patients with blindness and RP. The surgical steps are feasible, and the postoperative follow-up disclosed an acceptable range of adverse events.

The high correlation of NIR fluorescence and reflectance indicated that part of the observed NIR fluorescence is pseudofluorescence, whereas gray-scale analysis indicated that both NIR autofluorescence and pseudofluorescence contribute to the NIR fluorescence images. Quantification of leakage of the imaging system indicated a significant part of the observed NIR fluorescence is NIR autofluorescence. As NIR fluorescence derives from pigmented lesions, melanin is a possible source if NIR reflectance is also increased. Comparison with blue-light-excited autofluorescence showed differences between AMD and patients with nevi. NIR autofluorescence was also detected in single cases of maculopathy without corresponding NIR reflectance.

Measurements (autokeratometry, A-scan ultrasonography and video ophthalmophakometry) of ocular surface radii, axial separations and alignment were made in the horizontal meridian of nine emmetropes (aged 20-38 years) with relaxed (cycloplegia) and active accommodation (mean +/- 95% confidence interval: 3.7 +/- 1.1 D). The anterior chamber depth (-1.5 +/- 0.3 D) and both crystalline lens surfaces (front 3.1 +/- 0.8 D; rear 2.1 +/- 0.6 D) contributed to dioptric vergence changes that accompany accommodation. Accommodation did not alter ocular surface alignment. Ocular misalignment in relaxed eyes is mainly because of eye rotation (5.7 +/- 1.6 degrees temporally) with small amounts of lens tilt (0.2 +/- 0.8 degrees temporally) and decentration (0.1 +/- 0.1 mm nasally) but these results must be viewed with caution as we did not account for corneal asymmetry. Comparison of calculated and empirically derived coefficients (upon which ocular surface alignment calculations depend) revealed that negligible inherent errors arose from neglect of ocular surface asphericity, lens gradient refractive index properties, surface astigmatism, effects of pupil size and centration, assumed eye rotation axis position and use of linear equations for analysing Purkinje image shifts.

Ophthalmophakometric measurements of ocular surface radius of curvature and alignment were evaluated on physical model eyes encompassing a wide range of human ocular dimensions. The results indicated that defocus errors arising from imperfections in the ophthalmophakometer camera telecentricity and light source collimation were smaller than experimental errors. Reasonable estimates emerged for anterior lens surface radius of curvature (accuracy: 0.02-0.10 mm; precision 0.05-0.09 mm), posterior lens surface radius of curvature (accuracy: 0.10-0.55 mm; precision 0.06-0.20 mm), eye rotation (accuracy: 0.00-0.32 degrees; precision 0.06-0.25 degrees), lens tilt (accuracy: 0.00-0.33 degrees; precision 0.05-0.98 degrees) and lens decentration (accuracy: 0.00-0.07 mm; precision 0.00-0.07 mm).

Methods of therapeutic apheresis, such as plasma exchange or rheopheresis eliminate moderately aggregating macromolecules like fibrinogen, as well as strongly aggregating substances like alpha2-macroglobulin from blood. In order to examine the specific effect of eliminating alpha2-macroglobulin as a highly aggregating macromolecule, this study aimed to analyze the different rheological properties of: (i) moderately aggregating red blood cells (RBCs; inducible by fibrinogen); and (ii) strongly aggregating RBCs (inducible by alpha2-macroglobulin). In vitro, RBC aggregate geometry was determined in the presence of strong and moderate aggregation inducing macromolecules. In vivo, flow behavior of RBC aggregates was analyzed by intravital microscopy. Using network scanning, the number of perfused and non-perfused microvessels was determined. In vitro, the higher adhesive forces of strongly aggregating RBCs led to both a higher packing density of single RBCs within aggregates, expressed as a significantly reduced thickness of individual RBCs, and greater deformation, expressed as a significantly diminished offset between RBCs and an increased curvature of RBCs at the ends of the aggregates. In vivo rheoscopy showed that only high aggregating RBCs persisted in the precapillary bed and led to the absence of RBCs in up to 40% of nutritive capillaries. These novel findings are of importance regarding recent developments in clinical hemorheology, specifically the clinical use of hemapheretic therapies for diseases in which impaired microcirculation plays a role in either their development or progression, such as age-related macular degeneration and complications of diabetes mellitus. Our data support that procedures reducing the concentration of alpha2-macroglobulin in blood by extracorporeal elimination might provide a more efficient improvement of overall blood fluidity in microcirculatory beds.

We describe a non-invasive phakometric method for determining corneal axis rotation relative to the visual axis (beta) together with crystalline lens axis tilt (alpha) and decentration (d) relative to the corneal axis. This does not require corneal contact A-scan ultrasonography for the measurement of intraocular surface separations. Theoretical inherent errors of the method, evaluated by ray tracing through schematic eyes incorporating the full range of human ocular component variations, were found to be larger than the measurement errors (beta < 0.67 degrees , alpha < 0.72 degrees and d < 0.08 mm) observed in nine human eyes with known ocular component dimensions. Intersubject variations (mean +/- S.D.: beta = 6.2 +/- 3.4 degrees temporal, alpha = 0.2 +/- 1.8 degrees temporal and d = 0.1 +/- 0.1 mm temporal) and repeatability (1.96 x S.D. of difference between repeat readings: beta +/- 2.0 degrees , alpha +/- 1.8 degrees and d +/- 0.2 mm) were studied by measuring the left eyes of 45 subjects (aged 18-42 years, 29 females and 16 males, 15 Caucasians, 29 Indian Asians, one African, refractive error range -7.25 to +1.25 D mean spherical equivalent) on two occasions.

The FA findings confirm our previous results on the safety of the EPIRET3 system, which was tolerated in all patients but revealed a certain risk profile in regard to the stimulator fixation. While there was no evidence for newly occurred CME or CNV during the follow-up visits, nevertheless gliosis or even PVR reaction at the tack's fixation site suggests the need to develop alternative fixation procedures of epiretinal stimulators.

BackgroundThe purpose of this study was to test the effect of ethyl alcohol on the koniocellular and magnocellular pathway of visual function and to investigate the relationship between such visual field changes and retrobulbar blood flow in healthy subjects.MethodsIn 12 healthy subjects (mean age 32 ± 4 years), color Doppler imaging, short-wavelength automated perimetry, and frequency doubling perimetry was performed before and 60 minutes after oral intake of 80 mL of 40 vol% ethanol. Mean and pattern standard deviations for short-wavelength automated and frequency doubling perimetry were assessed. End diastolic velocity (EDV) and peak systolic velocity (PSV) were measured in the central retinal and ophthalmic arteries using color Doppler imaging. Systemic blood pressure, heart rate, intraocular pressure, and blood alcohol concentration were determined.ResultsMean PSV and EDV in the central retinal artery showed a significant increase after alcohol intake (P = 0.03 and P = 0.02, respectively). Similarly, we found a significant acceleration of blood flow velocity in the ophthalmic artery (P = 0.02 for PSV; P = 0.04 for EDV). Mean intraocular pressure decreased by 1.0 mmHg after alcohol ingestion (P = 0.01). Retinal sensitivity in short-wavelength automated perimetry did not alter, whereas in frequency doubling perimetry, the mean deviation decreased significantly. Systolic and diastolic blood pressure did not change significantly. Mean blood alcohol concentration was 0.38 ± 0.16 g/L.ConclusionAlthough ethanol is known to cause peripheral vasodilation, our subjects had no significant drop in systemic blood pressure. However, a significant increase of blood flow velocity was seen in the retrobulbar vessels. Regarding visual function, moderate alcohol consumption led to reduced performance in the magnocellular visual system tested by frequency doubling perimetry, but had no effect on short-wavelength automated perimetry.