In vivo confocal microscopy: corneal changes of hydrogel contact lens wearers

Abstract

To evaluate the corneal findings in hydrogel contact lens wearers by in vivo confocal scanning microscopy. One hundred and forty-two eyes of 71 myopic contact lens wearers (group 1) and 142 eyes of 71 non-contact lens wearers (group 2), whose age, gender and refractive error matched, were enrolled in order to detect the corneal changes by in vivo confocal microscopy through the central cornea. The average age was 25.5 ± 5.7 (16-52) and 25.6 ± 5.6 (17-49) in groups 1 and 2, respectively. The mean duration of contact lens wear was 43.9 ± 15.3 (6-240) months. Anterior keratocyte density was 667.5 ± 128.3 cells/mm(2) in group 1 and 821.4 ± 136.7 cells/mm(2) in group 2 (P = 0.001). Posterior keratocyte densities of groups 1 and 2 were 540.2 ± 87.6 cells/mm(2) and 628.2 ± 72.4 cells/mm(2), respectively (P < 0.001). Endothelial cellular density was 2611.2 ± 298.4 cells/mm(2) in group 1 and 2643 ± 218.2 cells/mm(2) in group 2 (P = 0.52). Ratio of polymegethism was 44.6 ± 8.8% in group 1 and 31.3 ± 4.7% in group 2 (P < 0.001). Epithelial cellular enlargement was observed in eyes wearing contact lenses with a mean Dk/t ratio of 26.5 × 10(-9) ± 5.9 (8.9-32 × 10(-9)). Stromal microdots occurred with contact lenses with a mean Dk/t ratio of 13.2 × 10(-9) ± 17.5 × 10(-9) (8.9-20 × 10(-9)). In vivo examination of the cornea with confocal microscopy revealed a number of changes. These changes can be attributed both to the mechanical and the hypoxic effects of soft contact lenses. In soft contact lenses with a high Dk/t ratio, these changes would be less frequent.

Evaluation of Corneal Endothelium in Adolescents with Juvenile Glaucoma

“…Their amount decreases by approximately 100–200 cells per year [ 1 ]. The endothelial cell dysfunction is observed in myopia and contact lense wear in young patients [ 2 , 3 ]. The decreasing number of endothelial cells can also be a result of diabetes mellitus [ 4 ].…”

Deep stromal opacities

“…Those who displayed microdot deposits had been wearing lenses for 13.6 ± 4.4 years, whereas those soft lens wearers who did not display microdot deposits had been wearing lenses for 8.2 ± 5.1 years. Yagmur et al 19 reported similar findings. These observations supports the finding of Trittibach et al 14 of an association between soft contact lens wear time and the size and density of microdot deposits.…”

Microdot Accumulation in the Anterior Cornea with Aging – Quantitative Analysis with in Vivo Confocal Microscopy

“…2 It has been suggested that this lipofuscin-like material within the corneal stroma of long-term contact lens wearers forms as a result of chronic oxygen deprivation and chronic microtrauma to the cornea. 2,5 Böhnke and Masters 2 hypothesized that microdots might be an early stage of irreversible corneal stromal alteration that may require treatment in the future. By contrast, Efron et al 27,33 believed that microdots might represent dysgenic or apoptotic cellular remnants lying dormant in the stroma, and should be considered a normal feature of human corneal morphology that perhaps could be altered by contact lens wear, which is in line with our findings of increased stromal microdot production and deposition in healthy aging corneas.…”

“…2 Later, these microdots were considered a type of corneal degenerative disease, and their incidence increased with contact lens wear. [2][3][4][5] Microdots have also been reported in patients following Thygeson's superficial punctate keratopathy, 6 amiodarone/Fabry keratopathy, [7][8][9] chronic and delayed mustard gas keratopathy, 10 Reis-Bücklers' corneal dystrophy, 11 and corneal surgery. 12 It has been hypothesized that they may be lipofuscin-like material that accumulates as a result of oxidative stress due to chronic hypoxia of the cornea.…”