Pharmacokinetics of Topically Applied Cyclopentolate HCI and Tropicamide

Age dependence of ocular biometric measurements under cycloplegia with tropicamide and cyclopentolate

“…It appears that for an accommodative demand of 6 D, tropicamide cycloplegia will induce an accommodative response of around 0.75 D, whereas for cyclopentolate one per cent, the response is around 0.25 D. The difference in accommodation response of 0.5 D between the two drugs would account for the remaining dioptric difference between the two drug conditions. Even greater potential sources of accommodative power may be available at the 25-minute measuring time 13 used by previous workers. 2,19 For brown irises, up to 35 per cent of accommodative amplitude may remain 20 minutes post-instillation of tropicamide-proparacaine combination, whereas about 18 per cent or less would remain at the 20 minute post cyclopentolate instillation time.…”

“…13,14 There are many published comparisons between the two common cycloplegic drugs cyclopentolate HCl and tropicamide HCl. 13,[15][16][17] The consensus is that cyclopentolate is more effective on younger children.…”

“…13,14 There are many published comparisons between the two common cycloplegic drugs cyclopentolate HCl and tropicamide HCl. 13,[15][16][17] The consensus is that cyclopentolate is more effective on younger children. Residual accommodation following cycloplegia with tropicamide is around 0.5 D greater than under cyclopentolate, although a clear distinction between the effectivities of these drugs for very young (less than eight years) compared with older (more than 12 years) children is not available.…”

“…Further, it is of interest to note that both time of measurement and iris colour significantly affect the magnitude of residual accommodation. 13 In this paper, we compare the ocular biometric measurements in a group of younger children (age five to 10 years) with those from an older group (age 16 to 19 years) treated on one occasion with the cycloplegic drugs one per cent tropicamide HCl in conjunction with one per cent proparacaine and at another time using only one per cent cyclopentolate HCl.…”

Intracameral Mydriatics in Cataract Surgery

“…Topically applied drugs generally penetrate the cornea slowly, with aqueous peak times ranging from 0.7 hours to 2.2 hours for various substances (Mishima 1981;Grass and Robinson 1988). For topically applied mydriatics the slow penetration through the cornea means a slow mydriatic onset (Lovasik 1986;Chien and Schoenwald 1990). For example, the peak mydriatic effect for cyclopentolate is at 30 minutes (Haaga, Kaila et al 1998) and for phenylephrine 75 minutes (Matsumoto, Tsuru et al 1982).…”