Estudo da pressão média da artéria oftálmica e da pressão de perfusão ocular em indivíduos submetidos à cicloergometria

Estudo da pressão média da artéria oftálmica e da pressão de perfusão ocular em indivíduos submetidos à cicloergometria

Autores:

Clóvis Paiva Filho,
Clóvis de Azevedo Paiva

ARTIGO ORIGINAL

Arquivos Brasileiros de Oftalmologia

versão impressa ISSN 0004-2749versão On-line ISSN 1678-2925

Arq. Bras. Oftalmol. vol.62 no.1 São Paulo fev. 1999

http://dx.doi.org/10.5935/0004-2749.19990052

SUMMARY

Purpose:

To compare the mean ophthalmic artery pressure (Pm ophth) and the ocular perfusion pressure (PP) of individuais submitted to physical effort with the mean brachial pressure (Pm brach), with the purpose of obtaining a better understanding of the autoregulation of the blood flow in the eyeball under physical stress.

Method:

The authors examined 36 volunteers submitted to physical effort by mean of an ergometric test. The ophthalmic artery pressure (P ophth) and the intraocular pressure (IOP) were measured at three phases: basal, effort and recuperation. The results were compared with the Pm brach.

Results:

During the basal phase, the Pm ophth corresponded to 71.12% of the Pm brach value. During the phase of maximum effort, the Pm brach increased 36.13% and the Pm ophth, 8.37%. Thus the relation between them decreased from 71.12% to 56.62%, i.e., it dropped from 0.71 mmHg to 0.56 mmHg, which represents a decrease of 2 1 . 1 2 %. Yet, in the effort phase, the PP underwent an increase of 17.4% ar 9.43 mmHg.

Conclusions:

This study would like to demonstrate the existence of an auto regulatiory mechanism that controls the blood flow to the eye even when Pm ophth does not increase in the sarne proportion as the Pm brach, and, also, that there would exist an increase of the PP responsible for a greater oxygen supply to the optic disc, during physical effort.

Keywords: Ophthalmic artery pressure; Ocular perfusion pressure; Cycloergometry; Ophthalmodynamometry

REFERÊNCIAS

1 Alm A, Bill A. Ocular circulation. ln: Moses RA, Hart WM, Physiology of the Eye. St. Louis: CV Mosby Company 1987;183-203 .
2 Duke-Elder S. The Anatomy of the visual system. ln: Kimpton H. ed. System of Ophtalmology. London 1961;2:286-93.
3 Hayreh SS, Dass R. The ophtalmic artery, II. lntraorbital Course . Br J Ophtalmol 1962;46:165-84.
4 Hayreh SS. The ophtalmic artery, III. Branches. Br J Ophtalmol 1962;46:212-47.
5 Hayreh SS. Blood Suply of the Optic Nerve Head in Health and Disease. ln: Lambrou GN, Greve EL, eds. Ocular Blood Flow in Glaucoma. Amsterdan: Kluger & Ghedini Publications 1989;3-48.
6 Ellestad MM. Stress Testing: principies and practice. Philadelphia. FA Davis Company 1980;286p.
7 Weigelin E, Lobstein A. Ophthalmodynamometry. Basel (Switzerland) S . Karger 1963;134p
8 Astrand PO. Quantification of exercise capability and evaluation of physical capacity in man. Prog Cardiovas Ois 1976;19:51-66.
9 Bill A. Physiological Aspects of the Circulation in the Optic Nerve. ln: Helfmann K, Richardson KT, eds. Glaucoma: conception of a disease. Houston: Saunders WB 1978;97-103.
10 Alm A, Bill A. The oxygen supply o f the retina II. Effects o f high intraocular pressure and of increased arterial carbon dioxide tension on uveal and retinal blood flow in cats. A study with labelled microspheres incluinding flow determinations in brain and some other tissues. Acta Physiol Scand 1972;84:306-19 .
11 Alm A, Bill A. Ocular and optic nerve blood flow at normal and increased intraocular pressure in monkeys (Macaca irus) a study with radioactively labelled microspheres including flow determinations in brain and some other tissues. Exp Eye Res 1973;15:15-29.
12 Alm A, Bill A. The effect of stimulation of the sympathetic chain on retinal oxygen tension and uveal, retinal and cerebral blood flow in cats. Acta Physiol Scand 1973;88:84-94.
13 Ernest JT. Autoregulation of optic-disc oxygen tension. Invest Ophtalmol Vis Sci 1974;13:101-06.
14 Weinstein JM, Duckrow RB, Beard D, Brennan RW. Regional optic nerve blood flow and its autoregulation. Invest Ophtalmol Vis Sci 1983;24:1559-65 .
15 Almeida GV, Bonomo PP, Cohen R. Contribuição ao estudo da auto-regulação vascular da retina no glaucoma crônico. Arq Bras Oftal 1988;51(2):47-52 .
16 Raposo Filho A. Variações da pressão intra-ocular em pacientes submetidos ao teste cicloergométrico. Tese de Doutorado em Oftalmologia, apresentada à Escola Paulista de Medicina, 1992;63p.