A prospective long-term study of the predictive value of the oscillatory potential in the development of proliferative diabetic retinopathy has been made in 137 diabetics. Follow-ups 6-8 and 13-15 years later demonstrated that recording the oscillatory potential in juvenile diabetics with a disease duration of more than 5 years is valuable in selecting those at risk of developing proliferative retinopathy within 6 years at any rate. The predictive value of the oscillatory potentials is probably more limited in women who later become pregnant.

The recording of blue cone (S-cone) responses as described by Gouras and MacKay was slightly modified and incorporated into our routine ganzfeld electroretinogram protocol. We found a mean S-cone amplitude of 5.0 microV (range 2.9-6.9 microV) and a mean S-cone implicit time of 41.5 msec (range 40-46 msec). Separation between the combined red and green cone (L-M-cone) response and the S-cone response was obtained with blue flash stimuli on a yellow adapting background.

The study draws a comparison between the oscillatory potential of the electroretinogram and the initial dark-adaptation measured by nyctometry, with the aim of assessing the predictive value of nyctometry in juvenile diabetics. The study included 61 insulin-dependent juvenile diabetics, aged 18-49 years, with a disease duration of more than five years. A statistically highly significant correlation could be demonstrated between alterations in the oscillatory potential and in the initial dark-adaptation. The results justify the assumption that nyctometry can be used as an easily handled clinical tool in selecting those at risk of developing proliferative retinopathy in their subsequent 6-8 years.

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To examine whether it is possible to enhance the level of 22:6(n-3) in the central nervous system, newborn rats were fed dietary supplements containing oils with either specific or random triacylglycerol structure, but similar concentrations of polyunsaturated fatty acids. In the specific structured oil, 22:6(n-3) was located in the sn-2 position, whereas it was equally distributed among the three positions in the triacylglycerol molecule in the randomized oil. A reference group was fed rat milk before weaning and nonpurified diet after weaning. After 12 wk, the levels of 22:6(n-3) in brain and liver phospholipids were higher in the groups fed the experimental diets than in the reference group. The specific structured oil resulted in the highest level of 22:6(n-3) in the brain, whereas the level of 22:6(n-3) was highest in the liver of the group fed randomized oil, indicating differences in metabolism of fatty acids resulting from their position in the dietary triacylglycerol molecule. The higher levels of 22:6(n-3) were accompanied by significantly lower levels of the long-chain (n-6) polyunsaturated fatty acids compared with the reference group. The fatty acid profiles, including the level of 22:6(n-3), in the retina phospholipids were not affected by the three different diets apart from a lower level of 20:4(n-6) in rats fed the experimental diets, indicating a strong tendency to maintain a high level of 22:6(n-3) in the retina. The changes in the fatty acid profiles did not result in differences in learning ability, but caused changes in visual function, evidenced by higher latency of the b-wave and lower oscillatory potential, and in auditory brainstem response, evidenced by generally greater amplitude of wave Ia in the group fed specific structured oil.