ACCOMMODATIVE RESPONSE CHANGES WITH AGE MEASURED BY PATTERN ELECTRORETINOGRAM

To evaluate whether the transient pattern electroretinogram reflects a ccommodation, we studied the amplitudes of the P-N component of transi ent pattern electroretinograms that were elicited in normal volunteers by reversing the checkerboard pattern. The stimuli were presented at a rate of three-reversals per second at a viewing distance of 20 cm. E ach subject wore a lens that corrected for distance vision. The ophtha lmic lenses were placed in front of the eye. A +12-diopter lens was us ed first, followed by lenses in decreasing 1-diopter steps, including minus lenses, until no response was recordable. The P-N amplitude was then plotted against increased accommodative stimulus. The graph showe d a rapid increase to around 4 diopters, and then a slow decrease with increasing minus lens power. The gradually decreasing part of the gra ph became steeper under cycloplegic conditions. The amplitude of accom modative response was defined as the difference in diopters between th e lens powers for eliciting an electroretinogram amplitude after cyclo plegia was achieved and in the untreated pupil. The amplitude of accom modative response attenuated significantly in those subjects older tha n 40 years.