It is well known that radiation from welding arcs can cause keratoconjunctivitis and 'glassblower's cataract'. In literature only few cases of welding arc maculopathy have been reported. Three cases are presented.
The paper presents a new test method for investigations of threshold curves for the resolving power of the eye and for exact measurements of visual acuity. This method measures static visual acuity within confidence limits of 9% compared to the acuity steps in Snellen notation of 33% to 50%. Furthermore, the method introduces the slope of the threshold curve as a parameter of suggested importance in the judgement of visual capability. The test mathematic is based on a method described by Finney (1952) for calculations on dose-response curves. To calculate the results and the test statistics an iterative curve fitting programme was designed to be run on a micro-computer. By connecting the presentation system and the response panel to the same computer the test could be performed almost automatically. The new test method was used to study visual acuity measured by projected ortotypes compared to acuity when measured by printed ortotypes. Tests using projected ortotypes were found to equal traditional acuity measurements, but the test results stressed the need for perfect and adjusted optics when projecting systems are used in visual acuity test.
Based on a period of introduction with the vitrectomy technic the visual acuity results in 143 consecutive cases performed between 1976 and 1980 are related to the anamnestic information, the pre-, per- and post-operative findings. In this introductional period the patients referred had longstanding retinovitreal changes, and, because of lack of prognostic parameters, all patients were offered surgery regardless of the observed pathology. All vitrectomies were carried out with the Klöti macrostripper and diathermy unit, without any additional instrumentation. From the results of these early cases, we have changed our surgical method to a three-port entrance with a separate infusion canula, a separate fiberoptic illumination and an interchange between vitrector, automatic scissors, hook, stilleto, vacuo needle, forceps and intravitreous photocoagulation through a third port. Diabetics should be offered vitrectomy if vitreous haemorrhages last for more than 3 months. Vitrectomy is considered useless or contraindicated in diabetics with lack of light perception or light projection, neovascular glaucoma, extinguished visual evoked potential. Only an improvement in the peripheral vision can be expected in diabetics with macular detachment. In rhegmatogenous detachment cases with intravitreal traction, vitreous operations should be performed only where intraretinal or retroretinal changes do not prevent mobilization or unfolding of the retina. Traumatic vitreoretinal disorders should be operated upon early.
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