P 328 Contraction of human ciliary muscles of aged phakic and aphakic eys in response to carbachol

Purpose: Human ciliary muscles were studied in terms of their response to carbachol in order to evaluate functional changes caused by ageing and disuse after lens extraction. Methods: Human ciliary muscles of 10 enucleated phakic eyebafls(5 cases under 70, 5 of 70 years or over) and an enucleated aphakic eyeball of an 63 year old individual obtained at autopsy were dissected in the meridional direction to give ciliary muscle strips. One end of each strip was clamped in a constant temperature(37OC) bath containing oxygenated Krebs solution and the other was tied to a mechano-transducer(Nihon Koden, Japan). Results: Mean values for contractile amplitude of ciliary muscles from cases under 70 years of age were 7.3+4.5mg with carbachol at 10-7 mol. 39.2+6.0mg at 10-6 mol. 652+161mg at 10-5 mol and 66.7+17.6mg at 10-4 mol. Mean values for 70 years or over were 11.9+3..2mg at IO-7 mol, 41.3+7.4mg at 10-6 mol, 56.2+11.2mg at 10-5 mol and 67.9+13.6mg at 10-4 mol. There was no significant difference in contractile amplitude between groups under 70 and 70years of over. The l/2 peak time of maximum contraction amplitude also did not differ between groups under 70 and 70 years or over. There was also no significant difference in either contractile amDlitUde or l/2 Deak time of maximum contraction amplitude' between the aphakic eye from the 63 year case and phakic eyes aged 70 years or over. Conclusions: Ciliary muscles of aged phakic eyes retained contractile potential and this is also the case for aphakic eyes even long after lens extraction.