Aqueous flare in patients with monocular iris atrophy and uveitis. A laser flare and iris angiography study.

PURPOSE: To study aqueous flare longitudinally in patients with Fuchs' heterochromic uveitis (FHU) and for comparison in another group with iris atrophy (non FHU). METHODS: A new laser flare meter was used. Iris angiography was performed in most FHU patients. RESULTS: The flare values in the affected eyes in the FHU group were always higher compared to the normal eyes and rather constant over time. Cataract surgery did not permanently change the flare values. Systemic - but not local steroid therapy caused normalization of the flare. Iris angiography displayed leakage in all FHU eyes. Leakage from original vessels dominated although some newly-formed leaking vessels were observed. CONCLUSIONS: The results support the notion that FHU is a low grade, chronic, stable disease. Leaking iris vessels, original or newly-formed, are probably the source of the increased flare. Our hypothesis is that inflammation plays a major part. Atrophy per se does not enhance flare.

Simultaneous machining of parallel grooves in SnO(2) thin films using a Nd:YAG laser and a kinoform.

A kinoform is used to split the beam of a Nd:YAG laser into six beams. The laser beams are, by means of optical fibers and collimating-focusing optics, transferred to the surface to be machined. Thus multiple grooves can be machined simultaneously. For demonstration, 100-µm-wide grooves are simultaneously machined into a SnO(2) thin film deposited on a glass substrate. The resulting grooves are well isolated. This result shows that the technique could be used, for example, in solar cell manufacturing to increase the efficiency of laser scribing.

Laser-machining experiment with an excimer laser and a kinoform.

We have used a kinoform to increase the beam-power utilization in an excimer-laser-machining experiment. The kinoform creates the pattern to be machined. Thus less power is wasted on the blocking parts of a shadow mask. To achieve as smooth an intensity profile as possible, the kinoform was also used together with a microlens-array beam homogenizer. We discuss the intensity distributions of the patterns created by the kinoform with and without the beam homogenizer as well as the design of the kinoform and the homogenizer, with emphasis on the relation to the coherence properties of the laser beam.

Design, calibration, and testing of a laser flare meter.

A laser flare meter, insensitive to corneal, lens, and eye background scattering and calibrated by measurements and theoretical modeling, is reported. Calibration measurements and theoretical calculations of light scattering from albumin solutions were found to agree within the limits of error. The results from in vivo measurements of normal eyes of different ages agreed well with normal protein content of aqueous humor. A special aperture design was used to reduce the unwanted background scattering resulting in signal-to-background ratios between 1:1 and 1:3 for normal eyes. Moderately cataractous eyes, with increased scattering from the lens, could be measured with sufficient accuracy. The reproducibility was measured to be ~ 12%. We studied how the flare is affected by sex, right/left eye, eye color, time of day, pupillary dilation, and an intraocular pressure measurement. No differences of practical importance were found.