Diurnal Curve of the Ocular Perfusion Pressure.

Fabio N Kanadani,J Corradi,Bsp Bezerra,Mp Vianello,Tca Moreira,Sk Dorairaj,Ts Prata

doi:10.5005/jp-journals-10008-1195

Abstract

ABSTRACTPurpose: To describe the diurnal variation of the ocular perfusion pressure (OPP) in normal, suspects and glaucoma patients.Materials and methods: Seventy-nine subjects were enrolled in a prospective study. The diurnal curve of intraocular pressure (IOP) was performed and blood pressure measurements were obtained. Each participant was grouped into one of the following based upon the clinical evaluation of the optic disk, IOP and standard achromatic perimetry (SAP): 18 eyes were classified as normal (normal SAP, normal optic disk evaluation and IOP < 21 mm Hg in two different measurements), 30 eyes as glaucoma suspect (GS) (normal SAP and mean deviation (MD), C/D ration > 0.5 or asymmetry > 0.2 and/or ocular hypertension), 31 eyes as early glaucoma (MD < -6 dB, glaucomatous optic neuropathy and SAP and MDs on SAP. Standard achromatic perimetry was performed with the Octopus 3.1.1 Dynamic 24-2 program. Intraocular pressure and blood pressure measurements were taken at 6 am, 9 am, 12, 3 and 6 pm. The patients stayed in the seated position for 5 minutes prior to blood pressure measurements.Results: The mean IOP values in all groups did not follow any regular pattern. The peak IOP was found to be greater in suspect [18.70 ± 3.31 (mm Hg ± SD)] and glaucoma (18.77 ± 4.30 mm Hg) patients as compared to normal subjects (16.11 ± 2.27 mm Hg). In studying the diurnal variation of the OPP, we found lower values at 3 pm in normals (34.21 ± 2.07 mm Hg), at 9 am in suspects (54.35 ± 3.32 mm Hg) and at 12 pm in glaucoma patients (34.84 ± 1.44 mm Hg).Conclusion: Each group has a specific OPP variation during the day with the most homogeneous group being the suspect one. It is important to keep studying the IOP and OPP variation for increased comprehension of the pathophysiology of glaucomatous optic neuropathy.How to cite this article: Kanadani FN, Moreira TCA, Bezerra BSP, Vianello MP, Corradi J, Dorairaj SK, Prata TS. Diurnal Curve of the Ocular Perfusion Pressure. J Curr Glaucoma Pract 2016;10(1):4-6.

Highlights

The two main theories for pathogenesis of the glauco matous optic neuropathy (GON) are vascular and mecha nical
The peak intraocular pressure (IOP) was found to be greater in suspect [18.70 ± 3.31] and glaucoma (18.77 ± 4.30 mm Hg) patients as compared to normal subjects (16.11 ± 2.27 mm Hg)
In studying the diurnal variation of the ocular perfusion pressure (OPP), we found lower values at 3 pm in normals (34.21 ± 2.07 mm Hg), at 9 am in suspects (54.35 ± 3.32 mm Hg) and at 12 pm in glaucoma patients (34.84 ± 1.44 mm Hg)

Summary

Introduction

The two main theories for pathogenesis of the glauco matous optic neuropathy (GON) are vascular and mecha nical. Both have been defended by research groups on the last 150 years. Acute angle close and secondary glaucoma, clearly the increase in intraocular pressure (IOP) is enough to cause GON. The fact is that the reduction of the ocular blood flow (OBF) frequently precedes the structural damage. It occurs in other parts of the body of these glaucomatous patients, indicating that hemodynamic adjustments can at least partially be primary. The biggest cause of this reduction is not atherosclerosis, but a vascular disequilibrium that leads to the reduction of the ocular perfusion pressure (OPP) and insufficient autoregulation.[1]

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