Green lasers are beyond power limits mandated by safety standards.

There has been an increasing number of reports of people losing vision from laser exposure from pocket laser pointers despite the safety limit of 1 milliwatt (1mW) imposed by the Australian government. We hypothesize that this is because commercially available red and green laser pointers are exceeding their labeled power outputs. We tested the power outputs of 4 red and 4 green lasers which were purchased for less than AUD$30 each. The average of 10 measurements was recorded for each laser. We found that 3 out of 4 red lasers conformed to the 1mW safety standard; in contrast, all of the green lasers exceeded this limit, with one of the lasers recording an output of 127.9 mW. This contrast in compliance is explained by the construction of these lasers - green lasers are typically Diode Pumped Solid State (DPSS) lasers that can emit excessive infrared (IR) radiation with poor workmanship or inconsistent adherence to practices of safe design and quality control; red lasers are diode lasers which have limited power outputs due to `Catastrophic Optical Damage' (COD). Relevant professional bodies ought to advocate more strongly for stringent testing, quality control and licensing of DPSS lasers with a view towards government intervention to banning green laser pointer use.

Lesion topography and new histological features in feline taurine deficiency retinopathy.

Previous studies of feline taurine deficiency retinopathy have established that the retinopathy begins as a focal lesion at the area centralis (feline central retinal degeneration) and progresses to form a horizontal band of retinal degeneration which, in some cases, eventually involves the whole retina. Several theories have been proposed to account for the strikingly unusual geographic distribution of lesions in this disease, including a preferential cone photoreceptor effect, and damage by exposure to light. In this paper evidence is provided that the regional lesions in advanced cases of taurine deficiency retinopathy extend circumferentially to form a peripheral annular band-like arrangement around the retinal extremity. The circumferential annulus is confluent with both temporal and nasal extremes of the horizontal band-shaped lesion. The topographic arrangement of the advanced lesion thus approximates the shape of the Greek letter theta, theta. A previously unreported sclerad displacement of photoreceptor cells into the subretinal space was commonly observed histologically. Radially sectioned material also revealed pathological changes in photoreceptors over a much more widespread region than the focal lesions observable ophthalmoscopically and in whole-mounts of the retina. The issue is therefore to account for the advanced photoreceptor cell loss in the focal lesions. A preferential effect on cone photoreceptors is insufficient to explain the lesion distribution, and unilateral tarsorrhaphy experiments exclude light damage as a major factor. Some other factor, or combination of factors, is most likely involved in determining the unique geographic distribution of lesions in feline taurine deficiency retinopathy.

Interferon-alpha 2b inhibits proliferation of human Tenon's capsule fibroblasts.

To evaluate the potential of interferon-alpha 2b (IFN-alpha) as an antifibrotic treatment after glaucoma filtering surgery, we studied its ability to inhibit mitogen-induced proliferation of human Tenon's capsule fibroblasts in vitro, as shown by [3H]-thymidine incorporation. IFN-alpha inhibited fetal calf serum-induced proliferation in a dose-dependent manner in concentrations ranging from 10 to 10,000 IU/ml (P < 0.001). Inhibition was also found when IFN-alpha was added prior to the mitogen (P = 0.001); this inhibitory effect lasted at least 3 days. We suggest that IFN-alpha deserves further evaluation as a possible agent for the control of ocular fibrosis.