The Effect of Lifting the Lids on Corneal Astigmatism

Wilson, Graeme; Bell, Christopher; Chotai, Shirish

doi:10.1097/00006324-198208000-00008

Cited by 80 publications

(34 citation statements)

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“…Shear stress is created by the interaction of the eyelid and the cornea during a blink, with the magnitude of the shear stress determined by the pressure that the eyelid applies to the cornea [16]. Although few studies on eyelid pressure have been published due to the technical difficulty of making this measurement in vivo, several studies have suggested that there is a relationship between eyelid pressure and changes in corneal topography, particularly induced astigmatism [17][18][19][20][21][22]. Demographic data on refractive error show higher average levels of astigmatism in Asians compared with nonAsians, which could be due to the Asian eyelid having a narrower palpebral aperture, greater eyelid volume and thus higher eyelid tension.…”

Section: Discussionmentioning

confidence: 99%

Corneal epithelial permeability: Ethnic differences between Asians and non-Asians

Li¹,

Hsiao²,

Graham³

et al. 2013

Contact Lens and Anterior Eye

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a b s t r a c tPurpose: To ascertain whether a difference in the permeability of the corneal epithelium to fluorescein (P dc ) exists between Asians and non-Asians. Methods: From a multi-study database we extracted 632 records of baseline, open-eye P dc measurements taken on both eyes of 176 subjects. Subjects were awake for a minimum of 4 h before measurement, and were free of ocular disease and central corneal staining. P dc was transformed by natural logarithm to better approximate normality for statistical tests. Results: The mean ln(P dc ) in the Asian group was significantly greater than in the non-Asian group [−2.34 ln(nm/s) vs. −2.58 ln(nm/s); p < 0.001]. Conclusions: Compared with non-Asians, Asians exhibited a less negative ln(P dc ), which translates to a higher P dc and a more permeable corneal epithelium. We speculate that this may be related to anatomic differences responsible for greater eyelid tension in Asians.

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Section: Discussionmentioning

confidence: 99%

Corneal epithelial permeability: Ethnic differences between Asians and non-Asians

Li¹,

Hsiao²,

Graham³

et al. 2013

Contact Lens and Anterior Eye

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“…6,[9][10][11] Altered pressure from normal eyelids also influences corneal astigmatism; eg, eyelid retraction 12,13 and narrowing of the palpebral aperture. [12][13][14][15] The presence of the eyelids on the cornea typically causes a 90-/180-degree astigmatic change. 13,14 The narrowed palpebral aperture associated with downward gaze induces corneal topography changes that are wave-like horizontal bands of distortion parallel to the eyelid margin.…”

mentioning

confidence: 99%

Corneal refractive changes due to short-term eyelid pressure in downward gaze

Shaw¹,

Collins²,

Davis³

et al. 2008

Journal of Cataract and Refractive Surgery

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The pressure of the eyelids on the cornea in short-term downward gaze resulted in optically and clinically relevant corneal changes. Correlation between the refractive corneal changes and eyelid parameters suggests that the angle, shape, and position of the eyelids influence the nature of the corneal changes. When high accuracy is required, refraction should be qualified by the visual tasks undertaken before assessment.

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“…6 Recently, the impact of the eyelid's pressure on corneal distortion has been examined in more detail, [7][8][9][10] and it was believed to cause transient monocular diplopia, a visual phenomenon observed after a long period of reading. 11,12 In 2001 13 and 2003, 14 the corneal changes after reading were examined with improved videokeratography and analyzed using wavefront techniques.…”

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confidence: 99%