Effects of long-term soft contact lens wear on the corneal thickness and corneal epithelial thickness of myopic subjects

Abstract

To perform safe and successful corneal refractive surgery on myopic patients, corneal thickness (CT) and corneal epithelial thickness (CET) must be accurately measured. Numerous individuals with myopia wear soft contact lenses (SCLs) for the correction of visual acuity but may subsequently undergo corneal refractive surgery. The aim of the present study was therefore to investigate the effects of long-term SCL wear on the CT and the CET of myopic subjects in order to guarantee the safety and accuracy of subsequent corneal refractive surgeries. Fifty-six subjects prepared to receive refractive surgery at Jinan Mingshui Eye Hospital (Zhangqiu, China) from April to July 2013 were included in the study. CT and CET were measured in subjects immediately following discontinued SCL wear (group I, 56 eyes), and subsequently following >two weeks of discontinued SCL wear (group II, 56 eyes). Ninety-four subjects with no history of corneal contact lens wear were enrolled as a control group. The CT and CET were measured at positions with a radius of 0.0‑1.0, 1.0-2.5 (divided into eight quadrants) and 2.5-3.0 mm (divided into eight quadrants) away from the corneal center using the RTVue-100 Fourier-domain anterior segment optical coherence tomography system. A significant decrease in the CT of the subjects in group II was observed, compared with that of group I and the control group (P<0.05). A significant decrease was observed in the CET of groups I and II compared with that of the control group (P<0.05). Following discontinuation of SCL wear, CET increased. However, the increased CET was unable to reach the normal range exhibited by the control group. Edema and thinning of the corneal stroma, as well as thinning of the corneal epithelium were observed in groups I and II. In conclusion, it was proposed that in clinical practice, for myopic patients following long-term SCL wear, CT and CET should be determined ≥ two weeks following discontinuation of SCL wear, once a stable CT and CET are obtained.

Refractive Errors & Refractive Surgery Preferred Practice Pattern®

“…[198][199][200][201][202][203][204][205] Transient subclinical stromal edema frequently occurs, and corneal thinning of the epithelium and stroma during contact lens wear has also been reported. 203,[206][207][208] Endothelial changes can occur, including polymegethism, pleomorphism, and, rarely, reduction of endothelial cell density. [209][210][211] The clinical significance of transient edema, thinning, and endothelial changes is uncertain.…”

Corneal Epithelium Thickness Profile in 614 Normal Chinese Children Aged 7–15 Years Old

“…Several methods have been introduced to measure CET, such as confocal microscopy 13 14 , optical pachymetry 15 , optical coherence tomography (OCT) 16 17 , high frequency ultrasound biomicroscopy 8 , and very high frequency digital ultrasound 18 . Fourier-domain optical coherence tomography (FD-OCT) is a high-speed, high-resolution, non-contact, 3-dimensional OCT, which has been applied in measuring CET for patients with keratoconus, corneal ectasia and dry eye, patients undergoing LASIK surgery, patients wearing soft or hard contact lenses and normal patients with relatively high repeatability 6 12 19 20 21 22 23 24 . This study presented CET maps of the central (2-mm diameter area), para-central (2- to 5-mm diameter area) and peripheral (6-mm diameter area) corneas in normal Chinese school children using FD-OCT.…”

Real-Life Variability of Corneal Epithelium Thickness in Photorefractive Keratectomy

“…The literature is controversial about whether age, gender, or refractive errors affect the corneal ET. [4][5][6][7] Several studies [8,14,17] showed a signi cant decrease in ET among CL-wear groups, with and an increase in thickness following discontinuation of the soft contact lenses. [8] It is important to note that our group of patients, seeking refractive surgery, were mostly young adults with varying degrees of myopia.…”

“…[1,3] Several factors have been shown to in uence the central epithelial thickness pro le, and while controversial in the literature, they include age, [4,5] gender, [4,6] ethnics and refractive errors. [6,7] Pathological conditions, such as contact lens (CL) wearing, [8] dry eye, [9,10] and keratoconus, [11] have been also shown to cause alterations of ET.…”