Eyelid Pressure and Contact with the Ocular Surface

Abstract

Purpose. To investigate static upper eyelid pressure and contact with the ocular surface in a group of young adult subjects. Methods. Static upper eyelid pressure was measured for 11 subjects using a piezoresistive pressure sensor attached to a rigid contact lens. Measures of eyelid pressure were derived from an active pressure cell (1.14-mm square) beneath the central upper eyelid margin. To investigate the contact region between the upper eyelid and the ocular surface, the authors used pressure-sensitive paper and the lissamine-green staining of Marx's line. These measures, combined with the pressure sensor readings, were used to derive estimates of eyelid pressure. Results. The mean contact width between the eyelids and the ocular surface estimated using pressure-sensitive paper was 0.60 +/- 0.16 mm, whereas the mean width of Marx's line was 0.09 +/- 0.02 mm. The mean central upper eyelid pressure was calculated to be 3.8 +/- 0.7 mm Hg (assuming that the whole pressure cell was loaded), 8.0 +/- 3.4 mm Hg (derived using the pressure-sensitive paper imprint widths), and 55 +/- 26 mm Hg (based on contact widths equivalent to Marx's line). Conclusions. The pressure-sensitive paper measurements suggested that a band of the eyelid margin, significantly larger than the anatomic zone of the eyelid margin known as Marx's line, had primary contact with the ocular surface. Using these measurements as the contact between the eyelid margin and the ocular surface, the authors believe that the mean pressure of 8.0 +/- 3.4 mm Hg is the most reliable estimate of static upper eyelid pressure.

The Lid Wiper Contains Goblet Cells and Goblet Cell Crypts for Ocular Surface Lubrication During the Blink

“…4,18 (4) A functional clinical study suggested that a zone in the width of about 600 mm, which would be within the range of the width of the lid wiper 5,10,15 (Knop et al 2007, Abstract at the TFOS 2007 Conference), is the contact zone of the eyelid border with the globe. 21 However, a previous study by the same group had reported some evidence that the line of Marx of about 100-mm width was the primary site of contact with the globe. 22 This assumption of the line of Marx being the wiping zone was also shared by other authors.…”

Effects of wearing a daily disposable lens on tear film: a randomised controlled trial

“…33 Alternatively, the lens may prevent frictional contact between the lid and the cornea during the blink, which can also stimulate nociceptors. 34,35 Lastly, microscopic epithelial defects may heal faster due to the bandage effect. 36…”

Vertical and Horizontal Thickness Profiles of the Corneal Epithelium and Bowman's Layer after Orthokeratology

“…First, the upper eyelid might generate greater pressure on the superior cornea than the inferior cornea. [23][24][25] This could produce less edema or even a thinning of the epithelium at the superior midperiphery. Second, although the fitting of the OK lens was acceptable in the clinic and the visual acuity was satisfactory to all subjects, superior decentration of the lens might have occurred in most of our subjects.…”