Assessment of the efficacy of eyeball local vacuum compression with a new suction cup for impedance oculopneumoplethysmography depending on anatomical parameters of the eye
A.G. Kovalchouk1, I.V. Potapenko2
1SI “The Filatov Institute of Eye Diseases and Tissue Therapy of the National Academy of Medical Sciences of Ukraine”; Odesa (Ukraine)
2 Odessa National I.I. Mechnikov University; Odesa (Ukraine)
Kovalchouk AG, Potapenko IV. Assessment of the efficacy of eyeball local vacuum compression with a new suction cup for impedance oculopneumoplethysmography depending on anatomical parameters of the eye. J.ophthalmol.(Ukraine).2020;1:57-67. http://doi.org/10.31288/oftalmolzh202015767
The relationship between the eyeball size and convexity of its anterior part and the efficacy of local vacuum compression of the eye performed using a new design suction cup for impedance ophthalmopneumoplethysmography was studied. Based on the mathematical modeling of the geometric shape of the anterior segment of 75 eyes obtained by ultrasound biomicroscopy examination, it was found that the horizontal meridian curve of the anterior eye segment with a base diameter of 16.00 mm could be best approximated by a hyperbola. The surface area under the new suction cup with an inside diameter of about 16.5 mm was calculated using the formula for the segment surface area of a hyperboloid of revolution. It was determined by the convexity of the anterior part of the eye and varied from 247.3 to 271.4 mm2. The conversion coefficient of the level of applied vacuum to the level of IOP rise, calculated on the basis of individual combinations of the surface area of local vacuum compression and the eyeball size, was on average 0.83 ranging from 0.44 to 1.33. Using an individual conversion coefficient according to eyeball anatomical parameters will make it possible to measure diastolic ocular perfusion pressure during impedance OPPG with high sensitivity and accuracy.
Keywords: impedance ophthalmopneumoplethysmography, mathematical modeling of the shape of the anterior eye, intraocular pressure, ocular perfusion pressure, local vacuum compression of the eyeball, ultrasound biomicroscopy
1.Kovalchouk A.G. Theoretical justification of a new method in ciliary body microcirculatory ischemia diagnostics. National Journal glaucoma. 2017;16(4):69-78. (In Russ.)
2.Kovalchouk AG. Substantiating the potential for a new technique (impedance oculopneumoplethysmography) to diagnose microvascular ciliary body ischemia. J.ophthalmol.(Ukraine).2018;3:85-97.
3.Kovalchouk AG. [Substantiation of a New Method for Diagnosing Ciliary Body Microcirculatory Ischemia Based on Lower Diastolic Ocular Perfusion Pressure in Metarterioles] //Biofizika. 2018;63(4):812-24. In Russian.
4.Information Bulletin No. 23 issued 12.12.2016, based on Pat. of Ukraine №112192 issued 16.05.2016. [Instrument for non-invasive measuring of the perfusion pressure in the microvascular network of the ciliary body]. Author: Kovalchuk OG. Patent Holder: State Institution Filatov Institute of Eye Diseases and Tissue Therapy, NAMS of Ukraine. In Ukrainian.
5.Information Bulletin No. 2 issued 25.01.2019, based on Pat. of Ukraine №131602 issued 03.07.2018. [Instrument for non-invasive measuring of the perfusion pressure in the microvascular network of the ciliary body]. Author: Kovalchuk OG. Patent Holder: Kovalchuk OG. u201807455. In Ukrainian.
6.Vit VV. Vit VV. [The structure of the human visual system]. Odessa: Astroprint; 2003. 664p. In Russian.
7.Mandell RB, Helen StR. Mathematical model of the corneal contour. Br. J. Physiol. Opt. 1971;26:183-97.
8.Fihtengolts GM. [The course of differential and integral calculus]. Moscow: Nauka; 1966. 608p. In Russian.
9.Ernest J Terry, Desmond Archer, Alex E Krill. Ocular hypertension induced by scleral suction cup. Investigative Ophthalmology. 1972;11(1):29-34.
10.Gee William, Dale W Oller, Edwin J Wyllie. Noninvasive diagnosis of carotid occlusion by ocular pneumoplethysmography. Stroke. 1976;7:18-21.
11.Lyubimov GA. [On the role of rigidity in the development of intraocular pressure]. Glaucoma. 2006; 2:64–7. In Russian.
12.Elsheikh A, McMonnies CW, Whitford C, Boneham GC. In vivo study of corneal responses to increased intraocular pressure loading. Eye and Vision. 2015; 2(20).
13.Chung CW, Micha¨el JA, Girard MJ, Jan NJ, Sigal IA. Use and Misuse of Laplace’s Law in Ophthalmology. Invest Ophthalmol Vis Sci. 2016;57(1):236-45.
14.Downs JC, Roberts MD, Burgoyne CF. Mechanical environment of the optic nerve head in glaucoma. Optom Vis Sci. 2008;85(6):425-35.
The authors did not receive funding when conducting research and writing an article. No Conflict of Interest is declared.