Title: Thermodynamics of vitreoretinal surgery. Authors: Mario R Romano. Affiliation: 1 Department of Ophthalmology, Istituto di Clinica e Ricerca Humanitas, Milan, Italy Purpose: To evaluate changes in temperature (T) occurring inside the human eye during vitreoretinal surgery and to investigate the effects of such variations on intraocular tamponades. Methods: Intraocular T was monitored during the entire surgical time in 21 eyes of 21 patients undergoing pars plana vitrectomy for peeling of epiretinal membrane or repair of retinal detachment. During the entire surgical time, T in the vitreous cavity was monitored using a 25-gauge thermoprobe inserted through a trocar access at 3.5 mm from the limbus. Time points of statistical analysis were: T under static conditions (inflow off – outflow off), T under dynamic conditions (inflow on – outflow on), T in the presence of perfluorcarbon liquid (PFCL), T during endolaser treatment, and T under air infusion. We also recorded the effect of the T variations, under fix and variable intraocular pressure (IOP), on viscosity and emulsion of intraocular tamponades. Results: The overall average T in the vitreous cavity during vitreoretinal surgery was 27.3 (SD 2.5) °C. The mean vitreous T in static conditions was 26.8 (SD 1.4) °C, in dynamic conditions it was 24.4 (SD 1.7) °C. In the presence of PFCL filling, the T was 25.1 (SD 1.7), whereas during endolaser treatment it increased to 29.6 (SD 1.5) °C. Under air infusion, T increased to 29.3 °C. Under fix IOP control, the same variations in T determined a significant increase in shear viscosity of PFCL and silicone oil. Such increase in temperature induced also a change in the saturation point of intraocular tamponades, leading to emulsion and opalescence. Conclusion: Temperature in the vitreous cavity significantly increases in the presence of intraocular tamponades and during endolaser treatment, whereas it significantly decreases when both the inflow and the outflow fluid lines are open, and under air infusion. The viscosity of intraocular tamponades is affected by such variations, with clinically relevant consequences.
Thermodynamics of vitreoretinal surgery
Romano M
2012-01-01
Abstract
Title: Thermodynamics of vitreoretinal surgery. Authors: Mario R Romano. Affiliation: 1 Department of Ophthalmology, Istituto di Clinica e Ricerca Humanitas, Milan, Italy Purpose: To evaluate changes in temperature (T) occurring inside the human eye during vitreoretinal surgery and to investigate the effects of such variations on intraocular tamponades. Methods: Intraocular T was monitored during the entire surgical time in 21 eyes of 21 patients undergoing pars plana vitrectomy for peeling of epiretinal membrane or repair of retinal detachment. During the entire surgical time, T in the vitreous cavity was monitored using a 25-gauge thermoprobe inserted through a trocar access at 3.5 mm from the limbus. Time points of statistical analysis were: T under static conditions (inflow off – outflow off), T under dynamic conditions (inflow on – outflow on), T in the presence of perfluorcarbon liquid (PFCL), T during endolaser treatment, and T under air infusion. We also recorded the effect of the T variations, under fix and variable intraocular pressure (IOP), on viscosity and emulsion of intraocular tamponades. Results: The overall average T in the vitreous cavity during vitreoretinal surgery was 27.3 (SD 2.5) °C. The mean vitreous T in static conditions was 26.8 (SD 1.4) °C, in dynamic conditions it was 24.4 (SD 1.7) °C. In the presence of PFCL filling, the T was 25.1 (SD 1.7), whereas during endolaser treatment it increased to 29.6 (SD 1.5) °C. Under air infusion, T increased to 29.3 °C. Under fix IOP control, the same variations in T determined a significant increase in shear viscosity of PFCL and silicone oil. Such increase in temperature induced also a change in the saturation point of intraocular tamponades, leading to emulsion and opalescence. Conclusion: Temperature in the vitreous cavity significantly increases in the presence of intraocular tamponades and during endolaser treatment, whereas it significantly decreases when both the inflow and the outflow fluid lines are open, and under air infusion. The viscosity of intraocular tamponades is affected by such variations, with clinically relevant consequences.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
