Sympathetic influence on intraocular pressure

Purpose To apply wavelet analysis to investigate the sympathetic modulation upon intraocular pressure(IOP)of the cold pressure test Methods In an autonomic dedicated lab continuous and simultaneous recording of(IOP) with Pascal(DCT) and arterial blood pressure(BP) were made in 11 healthy individuals,of both sexes,in basal conditions and during 1minute of cold‐pressure test(CPT).The tests were in the morning period and in the 24h previous individuals were told not to smoke and to avoid xanthines or other stimulants ingestion. Individuals under medication or with other pathology that could affect the autonomic nervous system were excluded. Data analysis of IOP and systolicBP (SBP) in the time‐scale domain with wavelets(DB12)was performed, for both variables, during the last minute prior to test and during one minute upon test. In this last case,periods of 10s where individually analysed and the period with the largest value was the chosen for statist analysis using t‐Student test, Welch corrected(Ducla‐Soares et al, 2007).LFIOP and LFSBP were calculated and differences between basal and CPT values were considered significant where p<0.05. Data were expressed as mean±SEM., and for LF mmHg2 Results Data refer to 6 male and 5 female with a mean age of 49[40‐70] On CPT, a sympathetic challenging manoeuvre, an increase of SBP was observed. Wavelet analysis of both signals showed a significant increase of LFIOP and LFSBP from 0.13±0.15 and 8.66±1.51 to 0.37±0.26 mmHg2 and 18.7±4.5mmHg2, respectively, and a not significant change in IOP 17.0±2.6 to18.0±1.5 Conclusion Our data show a sympathetic signature on IOP correlated with that observed in BP. We show that wavelets are a suitable tool for the evaluation of sympathetic signature on short periods of IOP recorded by DCT