Effects of Isometric Resistance Exercise of Lower Limbs on Intraocular Pressure and Ocular Perfusion Pressure of Healthy Adults

Background Ocular perfusion pressure is commonly defined as mean arterial pressure minus intraocular pressure (IOP). Changes in mean arterial pressure or IOP can affect ocular perfusion pressure. IOP has not been studied in this context in the prone anesthetized patient. Methods After institutional human studies committee approval and informed consent, 20 patients (American Society of Anesthesiologists physical status I-III) without eye disease who were scheduled for spine surgery in the prone position were enrolled. IOP was measured with a Tono-pen XL handheld tonometer at five time points: awake supine (baseline), anesthetized (supine 1), anesthetized prone (prone 1), anesthetized prone at conclusion of case (prone 2), and anesthetized supine before wake-up (supine 2). Anesthetic protocol was standardized. The head was positioned with a pinned head-holder. Data were analyzed with repeated-measures analysis of variance and paired t test. Results Supine 1 IOP (13 +/- 1 mmHg) decreased from baseline (19 +/- 1 mmHg) (P < 0.05). Prone 1 IOP (27 +/- 2 mmHg) increased in comparison with baseline (P < 0.05) and supine 1 (P < 0.05). Prone 2 IOP (40 +/- 2 mmHg) was measured after 320 +/- 107 min in the prone position and was significantly increased in comparison with all previous measurements (P < 0.05). Supine 2 IOP (31 +/- 2 mmHg) decreased in comparison with prone 2 IOP (P < 0.05) but was relatively elevated in comparison with supine 1 and baseline (P < 0.05). Hemodynamic and ventilatory parameters remained unchanged during the prone period. Conclusions Prone positioning increases IOP during anesthesia. Ocular perfusion pressure could therefore decrease, despite maintenance of normotension.

Download Full-text

Evaluation of the effect of elevated intraocular pressure and reduced ocular perfusion pressure on retinal capillary bed filling and total retinal blood flow in rats by OMAG/OCT

Microvascular Research ◽

10.1016/j.mvr.2015.07.001 ◽

2015 ◽

Vol 101 ◽

pp. 86-95 ◽

Cited By ~ 21

Author(s):

Zhongwei Zhi ◽

William Cepurna ◽

Elaine Johnson ◽

Hari Jayaram ◽

John Morrison ◽

...

Keyword(s):

Blood Flow ◽

Intraocular Pressure ◽

Perfusion Pressure ◽

Retinal Blood Flow ◽

Ocular Perfusion Pressure ◽

Ocular Perfusion ◽

Retinal Capillary ◽

Elevated Intraocular Pressure ◽

Capillary Bed

Download Full-text

Evaluation of the circadian fluctuations of intraocular pressure and ocular perfusion pressure in different types of glaucoma

10.32512/jmr.1.1.2018/15.18 ◽

2018 ◽

pp. 15-18

Keyword(s):

Intraocular Pressure ◽

Perfusion Pressure ◽

Ocular Blood Flow ◽

University Hospital ◽

Ocular Perfusion Pressure ◽

Goldmann Tonometry ◽

Ocular Perfusion ◽

Objective Evidence ◽

Different Types ◽

Exfoliative Glaucoma

Background: Glaucoma is a frequent leading cause of blindness. Objective evidence showed that it can be secondary to optic nerve head hypoperfusion and autonomic dysfunction, not only to ocular hypertension. This makes the assessment of ocular blood flow a crucial step in the management of this disease. Aim: To investigate the circadian fluctuations of the intraocular pressure (IOP) and of the mean ocular perfusion pressure (mOPP) in patients with different types of glaucoma. Materials and methods: Sixty-five eyes of 65 glaucoma patients, managed in the Ophthalmology Department of the Careggi University Hospital, Firenze, Italy (2012-2014). Among these eyes, 22 had normotensive glaucoma (NTG), 21 hypertensive glaucoma (HTG), and 22 exfoliative glaucoma (XTG). The IOP was measured by Goldmann tonometry and the blood pressure, both systolic (sBP) and diastolic (dBP), by Riva-Rocci sphygmomanometry, at three time points (8am, 2pm, 8pm). The mOPP was then calculated according to the formula mOPP = [2/3 (2/3 dBP + 1/3sBP) - IOP]. Results: The fluctuations of IOP and mOPP were statistically significant in all the studied eyes (p<0.001 for all the comparisons). Both IOP and mOPP showed significantly larger fluctuations in the XFG eyes than in the NTG and HTG ones (p<0.001 for IOP and p=0.001 for mOPP). Conclusions: In our study, the mOPP had larger circadian fluctuations in eyes with XFG than in those with NTG and HTG. This parameter deserves to be assessed in all types of glaucoma. Key words: Glaucoma, intraocular pressure, mean ocular perfusion pressure.

Download Full-text