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1

Czy dieta może zmieniać jakość widzenia? Wpływ spożywanych produktów na parametry wzrokowe. Cz. 2

Liguz Jessika, Jóźwik Agnieszka, Boguta Anna

Optyka

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2024

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Nr 2

56--59

PL

Artykuł stanowi kontynuację tematu opisanego w poprzednim numerze OPTYKI. W tej części omówiono, jak na ciśnienie wewnątrzgałkowe (IOP) wpływa kofeina. Badania wykazały, że jej spożycie może prowadzić do krótkotrwałego wzrostu IOP, co może mieć znaczenie szczególnie dla osób z ryzykiem chorób oczu, takich jak jaskra. Ponadto, artykuł podkreśla istotność zbilansowanej diety w utrzymaniu zdrowia wzroku. Wcześniej zauważono, że witaminy D i C wpływają pozytywnie na rozwój gałki ocznej, a witamina A poprawia jakość widzenia w różnych warunkach oświetleniowych oraz wpływa na kondycję spojówki. Kwasy tłuszczowe omega-3 regulują produkcję łez, co przyczynia się do nawilżenia oka, podczas gdy omega-6 wpływają na odporność organizmu. Jest to kluczowe dla procesów widzenia i zapobiegania chorobom oczu, takim jak zaćma. Ponadto, luteina i zeaksantyna zmniejszają obrzęk dołka i poprawiają ostrość wzroku. Wskazuje się także na negatywny wpływ nadmiernego spożycia tłuszczów nasyconych i cholesterolu na progresję krótkowzroczności. Wnioski te podkreślają znaczenie zdrowego stylu życia i odpowiedniej diety dla utrzymania dobrego stanu zdrowia oczu.

EN

The impact of caffeine on intraocular pressure (IOP) is discussed in this part. Previous studies have shown that caffeine consumption can lead to a short-term increase in intraocular pressure, which may be particularly important as risk factor for eye diseases such as glaucoma. Additionally, the article emphasizes the importance of following a balanced diet in maintaining eye health. It was previously noted that vitamins D and C have a positive effect on the development of the eyeball, while vitamin A improves the vision quality in various lighting conditions and affects the condition of the conjunctiva. Omega-3 fatty acids regulate the tear production, contributing to the hydration of the eye, while omega-6 affects the body’s immunity Itis crucial for vision processes and the prevention of eye diseases such as cataracts. Moreover, it was noticed that lutein and zeaxanthin reduce macular edema and improve visual acuity. The article also highlights the negative impact of excessive consumption of saturated fats and cholesterol on the progression of myopia. These conclusions underscore the importance of a healthy lifestyle and proper diet in maintaining good eye health.

2

Applanation pressure function in Goldmann tonometry and its correction

Śródka W.

Acta of Bioengineering and Biomechanics

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2013

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Vol. 15, no. 3

97--106

EN

So far applanation tonometry has not worked out any theoretical basis for correcting the result of intraocular pressure measurement carried out on a cornea with noncalibration dimensions by means of the Goldmann tonometer. All the tables of instrument reading corrections for cornea thickness or cornea curvature radius are based exclusively on measurements. This paper represents an attempt at creating a mechanical description of corneal apex deformation in Goldmann applanation tonometry. The functional dependence between intraocular pressure and the pressure exerted on the corneal apex by the tonometer was determined from a biomechanical model. Numerical GAT simulations, in which this function was also interrelated with the cornea’s curvature radius and thickness were run and a constitutive equation for applanation tonometry, i.e. a full analytical description of intraocular pressure as a function of the above variables, was derived on this basis. The correction factors were defined and an algorithm for correcting the measured pressure was formulated. The presented formalism puts the results of experimental tonometry in new light. Analytical correction factors need not to come exclusively from measurements. A geometric interdependence between them and their dependence on pressure have been revealed. The theoretical description of applanation tonometry contained in the constitutive equation consists of a pressure function developed for a cornea with calibration dimensions and a coefficient correcting this calibration function, dependent exclusively on the cornea’s actual thickness and curvature radius. The calibration function is a generalization of the Imbert–Fick law.

3

Evaluating the material parameters of the human cornea in a numerical model

Śródka W.

Acta of Bioengineering and Biomechanics

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2011

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Vol. 13, no. 3

77-85

EN

The values of the biomechanical human eyeball model parameters reported in the literature are still being disputed. The primary motivation behind this work was to predict the material parameters of the cornea through numerical simulations and to assess the applicability of the ubiquitously accepted law of applanation tonometry – the Imbert–Fick equation. Methods: Numerical simulations of a few states of eyeball loading were run to determine the stroma material parameters. In the computations, the elasticity moduli of the material were related to the stress sign, instead of the orientation in space. Results: Stroma elasticity secant modulus E was predicted to be close to 0.3 MPa. The numerically simulated applanation tonometer readings for the cornea with the calibration dimensions were found to be lower by 11 mmHg then IOP = 48 mmHg. Conclusions: This discrepancy is the result of a strictly mechanical phenomenon taking place in the tensioned and simultaneously flattened corneal shell and is not related to the tonometer measuring accuracy. The observed deviation has not been amenable to any GAT corrections, contradicting the Imbert–Fick law. This means a new approach to the calculation of corrections for GAT readings is needed.

4

Biomechanical model of human eyeball and its applications

Śródka W.

Optica Applicata

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2009

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Vol. 39, nr 2

401-413

EN

Attempts at the mechanical identification of the human eyeball are often not very effective for two reasons: the material parameters determined by tension tests on corneal and scleral tissue specimens are not sufficiently accurate while numerical models of the eye, integrating material and geometric parameters, are often based on unrealistic assumptions. The examples presented here cover refractive surgery, Goldmann applanation tonometry and the optical self-adjustment of the eye. The discussed problems are illustrated with calculations showing that it is possible to effectively use a biomechanical model of the eye to identify its material parameters. Also the handicaps, the Imbert-Fick law among them (numerical calculations do not corroborate this law), lying at the basis of applanation tonometry are demonstrated. The conclusions can help to create a realistic numerical model of the eyeball.

5

Model numeryczny gałki ocznej do korekcji pomiarów ciśnienia wewnątrzgałkowego elektronicznymi tonometrami okulistycznymi

Hachoł A., Środka W., Szul E.

Elektronika : konstrukcje, technologie, zastosowania

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2007

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Vol. 48, nr 2

40-44

PL

Zaprezentowano model numeryczny gałki ocznej przeznaczony do korekcji pomiarów ciśnienia wewnątrzgałkowego elektronicznymi tonometrami okulistycznymi. Geometrię oraz parametry materiałowe zostały dobrane tak, aby uczynić model samonastawnym optycznie. Do budowy modelu numerycznego wykorzystano metodę elementów kończonych (pakiet Cosmos/M oraz oprogramowanie własne). Przedstawiono również wyniki badań symulacyjnych, pokazujące wpływ parametrów materiałów struktur oka, grubości rogówki i jej promienia oraz samego ciśnienia wewnątrzgałkowego na wynik pomiaru.

EN

The paper presents numerical model of the human eyeball which can be used for correction of intraocular pressure measurement using electronic ophthalmic tonometers. Investigated model based on the optical self-adjustment efect of the human eyeball for all value of IOP from the physiological range. The FEA method was used for the construction of the model. The exemplary results showing influence of the eye ball materials parameters, central corneal thicknes, radius of cornea curvature and IOP on the tonometric measurements result (obtained with the described model) have been presented.