Masaaki Ohashi1, Makoto Aihara2,3, Tadashiro Saeki1, Makoto Araie1. 1. Department of Ophthalmology, University of Tokyo School of Medicine, Tokyo, Japan. 2. Department of Ophthalmology, University of Tokyo School of Medicine, Tokyo, Japan. aihara-tky@umin.ac.jp. 3. Department of Ophthalmology, University of Tokyo School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. aihara-tky@umin.ac.jp.
Abstract
PURPOSE: To assess the efficacy of two noninvasive tonometers, TonoLab and TonoPen-XL, in detecting physiological or pharmacological changes of intraocular pressure (IOP) in rat eyes, by comparing them with the microneedle method. METHODS: Sprague Dawley rats, bred under a 12-h light-and-dark cycle, were used. Under systemic anesthesia, eyes were cannulated by a microneedle connected to a transducer and a water reservoir. Variable intracameral pressure was attained by changing the reservoir height, and the resulting tonometer readings were compared. Then, the daytime and nighttime IOP, and the effect at 2 h after latanoprost instillation, were measured with the three devices. RESULTS: TonoLab and TonoPen-XL readings (y) were strongly correlated with microneedle tonometer readings (x) (y=0.96x-4.3, r2=0.985, and y=0.48x+3.9, r2=0.985, respectively), but TonoPen-XL readings were only half those of the microneedle tonometer. Nocturnal elevation of IOP was significant both with TonoLab and with the microneedle tonometer (P<0.001), but not with TonoPen-XL. Latanoprost significantly elevated IOP by 3.0+/-2.1 with TonoLab and by 1.1+/-1.1 mmHg with the microneedle tonometer (P<0.05), but not with TonoPen-XL. CONCLUSION: TonoLab provides readings similar to those of a microneedle tonometer, and diurnal variations and drug effects were detectable. TonoLab promises to be a noninvasive and useful method for physiological and pharmacological studies in rat eyes.
PURPOSE: To assess the efficacy of two noninvasive tonometers, TonoLab and TonoPen-XL, in detecting physiological or pharmacological changes of intraocular pressure (IOP) in rat eyes, by comparing them with the microneedle method. METHODS:Sprague Dawley rats, bred under a 12-h light-and-dark cycle, were used. Under systemic anesthesia, eyes were cannulated by a microneedle connected to a transducer and a water reservoir. Variable intracameral pressure was attained by changing the reservoir height, and the resulting tonometer readings were compared. Then, the daytime and nighttime IOP, and the effect at 2 h after latanoprost instillation, were measured with the three devices. RESULTS: TonoLab and TonoPen-XL readings (y) were strongly correlated with microneedle tonometer readings (x) (y=0.96x-4.3, r2=0.985, and y=0.48x+3.9, r2=0.985, respectively), but TonoPen-XL readings were only half those of the microneedle tonometer. Nocturnal elevation of IOP was significant both with TonoLab and with the microneedle tonometer (P<0.001), but not with TonoPen-XL. Latanoprost significantly elevated IOP by 3.0+/-2.1 with TonoLab and by 1.1+/-1.1 mmHg with the microneedle tonometer (P<0.05), but not with TonoPen-XL. CONCLUSION: TonoLab provides readings similar to those of a microneedle tonometer, and diurnal variations and drug effects were detectable. TonoLab promises to be a noninvasive and useful method for physiological and pharmacological studies in rat eyes.
Authors: Wan-Heng Wang; J Cameron Millar; Iok-Hou Pang; Martin B Wax; Abbot F Clark Journal: Invest Ophthalmol Vis Sci Date: 2005-12 Impact factor: 4.799