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New extentive experiments demonstrated that: (a) protan observers are more deficient than deutan ones with regard to perception distances of some traffic panels, of vehicle red stop lights, of vehicle red rear-position lights and of white, yellow and red reflectors. Contrarily, deutan observers are more deficient than protan ones for the distinction of differently coloured traffic lights and vehicle rear lights; (b) protan and deutan drivers are nevertheless not responsible for more traffic accidents than drivers with normal colour vision; (c) this apparent contradiction is due to psychological compensation mechanisms. The practical conclusions are: (a) that persons with defective colour vision need not to be excluded from non professional road traffic; (b) that it is nevertheless useful that they should be aware of their handicap; (c) that the red traffic signal has to be larger than the other ones; and (d) that the stop and red position lights of vehicles must be sufficiently intense and that the filters transmitting only pure red should be avoided in them.

A 40-year-old Caucasian female was first seen 20 years ago for a routine ocular screening in relation to hydroxychloroquine treatment for systemic lupus erythematosus. Her daily dose was 600 mg (or 12 mg/kg of body weight/day) of hydroxychloroquine. Three years later, she complained of mild visual loss in the right eye. Her best-corrected visual acuity was 0.9 in the right (RE) and 1.0 in the left eye (LE). In addition, she had a central scotoma (RE > LE) on automated visual field analysis (Humphrey central 30 degrees ). On fundoscopy and fluorescein angiography, the first signs of a bilateral bull's eye maculopathy were detected. A decreased Arden ratio on EOG (<1.50) was found with an accompanying decreased amplitude of the scotopic b-wave on full-field electroretinography in both eyes. Consequently, the treatment was immediately stopped. During the following years, the patient was retested regularly. After more than 18 years after cessation of the drug, most tests showed a further deterioration, including best-corrected visual acuity (RE: 0.1; LE: 0.7). On visual field testing, a progressive evolution to a total and absolute central scotoma in the RE (central 10 degrees ) and an annular scotoma in the LE became apparent. In contrast, a partial recovery of the Arden ratio of the EOG to 1.8 in both eyes was seen. In addition, a partial recovery of the scotopic b-wave full-field ERG was noted 19 years after cessation of treatment. At retest visits respectively 18, 19 and 20 years after cessation of hydroxychloroquine, a multifocal electroretinogram was performed in combination with colour vision tests and contrast sensitivity measurements.

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Purpose: To investigate the type and severity of acquired colour vision deficiencies (CVDs) in molecularly proven Stargardt disease (STD) and to establish whether a relationship exists between best-corrected visual acuity (BCVA) and full-field electroretinography (ffERG), and the degree of CVD. Methods: A retrospective, cross-sectional study of 73 patients with a molecularly proven diagnosis of STD, who underwent extensive colour vision evaluation, using pseudo-isochromatic and arrangement tests. Thirteen patients underwent Nagel anomaloscopy. Results: Normal colour vision was found in almost 20% of patients. Red/green (R/G) CVDs increased as BCVA declined. About 45% of all R/G CVDs were of the deutan type, although protan type CVDs became progressively apparent when moving from the high to the low BCVA group. An additional blue/yellow CVD was noted in about 25% of patients. In 10/13 patients, a pseudoprotanomaly was noted on anomaloscopy. Severe CVDs leading to scotopization were noted in patients with low BCVA and/or long-standing disease. No statistically significant differences in ERG results were found between groups with or without a CVD. Conclusions: The degree and type of colour vision deficiency in STD patients correlate better with BCVA than with ffERG results. The presence of specific CVDs may help to establish a diagnosis of STD. A battery of colour vision tests is required to properly evaluate CVDs in STD.