Biomedical subjects
R Dethlefs
Publications and source records attributed to R Dethlefs.
Case reports of two variants of chronic progressive external ophthalmoplegia.
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Ocular manifestations and complications of acute methyl alcohol intoxication.
The ocular manifestations of acute methyl alcohol intoxication were studied in 24 men during an outbreak in Port Moresby, Papua New Guinea. The visual acuity, pupillary reactions to light, fundal appearances and visual fields were recorded in all patients within 72 hours of ingestion of methanol and again three months later. Three groups were identified. Nine patients had no ocular abnormality (Group 1). Seven patients had only transient ocular abnormalities (Group 2). Eight patients had permanent ocular abnormalities (Group 3). Transient abnormalities included peripapillary oedema, optic disc hyperaemia, diminished pupillary reactions to light, and central scotomata. Permanent ocular abnormalities included optic disc pallor, attenuation of arterioles, sheathing of arterioles, diminished pupillary reaction to light, diminished visual acuity, central scotomata, and other nerve fibre bundle defects. Complete blindness occurred in two patients, while severe visula deficit resulted in four others. The incidence of permanent ocular abnormalities was found to correlate with the incidence of metabolic acidosis (P less than 0.01), and with the stated volume of methanol consumed (P less than 0.05). An inverse correlation was found between stated volume of methanol consumed and onset of blurred vision. The difficulties in management and rehabilitation of these patients are discussed.
Observer bias as a factor in neonatal hearing screening.
To evaluate observer bias as a possible factor influencing neonatal hearing testing, two trained observers were asked to evaluate the behavior of 200 neonates at a moment the observers thought a stimulus was being presented. Observers were receiving masking noise, and when the stimulus button was pressed a stimulus might or might not be delivered to the child. Results suggest that observer bias is not a factor when arousal is the only acceptable response and is clearly defined, and the observers are limited to a yes-no decision. Sequential analysis of infant response patterns is presented and a specific test scoring protocol is outlined.
Nonvascular glaucoma.
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