Can Variability in Corneal Metabolism Explain the Variability in Corneal Swelling?

Bonanno, Joseph A.; Nyguen, Tracy; Biehl, Trina; Soni, Sarita

doi:10.1097/00140068-200301001-00003

Cited by 14 publications

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“…It has been reported that both the metabolic activity and the endothelial function are two factors that contribute to corneal swelling. 23,57 The interaction of these and other factors in the recovery from edema may occur to different extents between subjects and at different time points after removal of the hypoxic stimulus for each subject, resulting in a lack of systematic behavior for the group over time. A third and related possibility is that the En-DM complex response is more dynamic than the biphasic changes observed in other layers.…”

Section: Discussionmentioning

confidence: 99%

“…22 The rate of recovery of hypoxia-induced edema is thought to represent the endothelial pump function. [23][24][25] In humans, extended eye closure during contact lens wear is an effective model of hypoxia and has been used often to model the normal physiological response of the cornea 8,26 as well as in altered conditions in postsurgical [27][28][29] and lenswearing 24 patients.…”

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confidence: 99%

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Swelling of the Human Cornea Revealed by High-Speed, Ultrahigh-Resolution Optical Coherence Tomography

Hutchings¹,

Simpson²,

Hyun

et al. 2010

Invest. Ophthalmol. Vis. Sci.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Swelling of the Human Cornea Revealed by High-Speed, Ultrahigh-Resolution Optical Coherence Tomography

Hutchings¹,

Simpson²,

Hyun

et al. 2010

Invest. Ophthalmol. Vis. Sci.

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“…It may not be feasible to control for all possible individual differences that could possibly impact the CS in a single study. However, based on the literature, [28][29][30][31] we suggest adding individual measures of corneal oxygen demand (corneal Mixed Modeling of Between-Subject Corneal Swelling IOVS j May 2018 j Vol. 59 j No.…”

Section: Discussion Random Individual Contributions To Corneal Swellingmentioning

confidence: 99%

Mixed Model Analysis of Between-Subject Variability in Overnight Corneal Swelling and Deswelling With Silicone Hydrogel Lenses

Moezzi

Hutchings

Fonn

et al. 2018

Invest. Ophthalmol. Vis. Sci.

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PURPOSE.To model between subject variability of corneal swelling (CS) and deswelling after overnight wear of silicone hydrogel (SiHy) contact lenses. METHODS.A total of 29 neophyte subjects wore 12 SiHy lenses with central transmissibility range of 31 to 211 Dk/t units on separate nights, in random order, and on one eye only. The contralateral eye served as the control. Central corneal thickness was measured using digital optical pachymetry before lens insertion, immediately after lens removal on waking, then 20, 40 minutes, 1, 2, and 3 hours later. Mixed modelling was conducted for simultaneous analysis of group and between-subject effects of CS and deswelling.RESULTS. The best model for overnight CS versus Dk/t was linear with a random intercept showing constant between-subject differences in CS for different Dk/t values. The best fit for corneal deswelling versus time was a curvilinear random intercept and random slope model. About 90% of the total between-subject deswelling variance in either lens or control eyes was due to the intercept variability with much less (~10%) being due to the variability of the individual deswelling rate (slope). Subject age, sex, and ametropia were not predictors of individual corneal swelling in the swelling versus Dk/t analysis. Age, however, was a significant (inverse) predictor of the rate of corneal deswelling, only in lens-wearing eyes. CONCLUSIONS.A large proportion of variability in corneal swelling is because of subject-specific differences in corneal response to hypoxia. This shows that ''low swellers'' and ''high swellers'' actually do exist.Keywords: corneal swelling, corneal deswelling, between-subject variability, pachymetry, mixed modeling C orneal swelling is regarded as one of the main indices of corneal physiologic change as a result of corneal oxygen deficiency produced by contact lens (CL) wear.1,2 The postlens tear oxygen tension in soft lenses is dependent on the oxygen diffusion through the lens material 3,4 and the effect of the tear pump on tear mixing to equilibrate the oxygen tension under a soft lens is insignificant. 5,6 Therefore, oxygen diffusion through contact lenses plays a vital role in maintaining corneal health and normal physiology in soft lens wear. 7,8 Corneal oxygen deprivation may lead to corneal swelling (thickening) from water absorption by the corneal stroma. This is believed to primarily be from the increased stromal osmotic gradient resulting from the accumulation of lactic acid from anaerobic metabolism in the cornea.9 It would appear self-evident, therefore, that the level of lens induced corneal swelling is inversely related to the oxygen transmissibility of the contact lens. 10The average overnight corneal swelling of 3%-4% occurs in response to eye closure 11 in nonlens wearers 12-15 and sleeping with a contact lens on the eye, further deprives the cornea of the oxygen supply from the palpebral vasculature, maximizing the hypoxic stress and potentially leading to increased corneal edema. 16 Even silicone hydrogel (SiHy) lenses ...

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“…An important effect of the use of contact lenses is corneal swelling or edema, which can affect visual quality and visual acuity if large enough. Bonanno et al (38) concluded that corneal swelling is related to metabolic activity and endothelial function; however, other factors could also be involved, which may include physical forces, interlamellar tightness, or circumlimbal clamping. Changes in corneal thickness caused by these soft contact lenses under study are not clinically significant, since all the lenses introduced changes below 1.9% in central and peripheral corneal thickness, and Hess and Garner (39) stated that visual function is slightly compromised when the change in corneal thickness is about 6%.…”

Section: Discussionmentioning

confidence: 99%

Assessment of Modifications in Thickness, Curvatures, and Volume upon the Cornea Caused by Disposable Soft Contact Lens Wear

Águila-Carrasco

Domínguez‐Vicent

Pérez-Vives

et al. 2015

European Journal of Ophthalmology

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Can Variability in Corneal Metabolism Explain the Variability in Corneal Swelling?

Abstract: Corneal swelling is associated with corneal metabolic activity and endothelial function; however, other factors must also be involved. Contact lens wearers do not adapt by modifying oxygen consumption but probably by using glucose more efficiently.

Cited by 14 publications

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Swelling of the Human Cornea Revealed by High-Speed, Ultrahigh-Resolution Optical Coherence Tomography

Swelling of the Human Cornea Revealed by High-Speed, Ultrahigh-Resolution Optical Coherence Tomography

Mixed Model Analysis of Between-Subject Variability in Overnight Corneal Swelling and Deswelling With Silicone Hydrogel Lenses

Assessment of Modifications in Thickness, Curvatures, and Volume upon the Cornea Caused by Disposable Soft Contact Lens Wear

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