Local neuroretinal function during acute hypoxia in healthy older people.

Purpose: To measure the effect of acute, mild, systemic hypoxia on neuroretinal function in two different age groups.
Methods: The slow-flash paradigm of the multifocal electroretinogram (mfERG) was measured in two different oxygenation levels. Twelve participants of two age groups (28 +/- 4 and 55 +/- 5 years) breathed room air (normoxia) or 12% oxygen (hypoxia).
Results: During normoxia (SaO(2) = 98%) there was a significantly different effect between the younger and older participants on the mfERG positive waveform components (N1P1 amplitudes and P1 implicit times; P < 0.001). Hypoxia (SaO(2) = 90%) significantly decreased N1P1 response density amplitudes in the central retinal field in both groups, with a larger effect in the older group (P < 0.001). There was no significant change in function of the cellular generators of oscillatory potentials (OPs).
Conclusion: The results extend recent findings by showing a greater effect of hypoxia on ON- and OFF-bipolar cell function in healthy older persons than in younger persons, but no effect on OPs during moderate acute hypoxia in either age group.