Abstract
Abstract: :
Purpose: Previous studies have shown that contact lens wear causes an increase in Pseudomonas aeruginosa (PA) binding to the corneal epithelial surface. The aim of this study is to examine the effect of reversed geometry Orthokeratology lens wear on bacterial binding. Methods: 12 NZW rabbits (3–3.5kg) were used for this study and treated according to the ARVO statement for the use of animals in ophthalmic and vision research. Partial membranectomy was performed on all rabbits 1 week prior to lens fitting. One randomly chosen eye was fitted at 10:00am with either a RGP control lens (Menicon Z, Menicon Co. Ltd., Japan) or a reverse geometry OrthoK lens designed for the rabbit eye. Following 24–hours lens wear, rabbits were sacrificed. The eyeballs were enucleated and immediately placed in 0.5ml 1.0x107 CFU/ml bacterial solution (ATCC 27853). After incubation (30min.), the epithelium with adherent bacteria was scraped and cultured for 24–hours. Colony–forming unit method was used to quantify the data per eye. All PA–binding steps were carried out by a masked observer. Results: PA–binding in the RGP lens group was 0.93±0.37 and 1.69±0.59 105 CFU for respectively the control and lens wearing eyes (p=0.130). OK group: 1.17±0.81 (control) and 2.76±0.77 (OK lens) 105 CFU (p=0.003). PA–binding with the OK lens was significantly higher than the RGP (p=0.014). Conclusions: In the rabbit, OK overnight lens wear showed a statistically significant increase in bacterial binding to the corneal epithelium while the RGP control lens did not, even though both lenses are made from the same hyper O2 material. Human studies on bacterial binding on exfoliated corneal epithelial cells are needed to determine whether this PA increase also occurs in the human.
Keywords: contact lens • cornea: epithelium • cornea: basic science