Abstract
<jats:p>A total of 315 people (623 eyes) wearing orthokeratology lenses (OKLs) were examined. The condition of the eyes and OCLs was assessed dynamically. Critical levels of deposits on the OCLs were observed after 12 months in 35.0% of eyes, and scratches in 39.3%. Decreased visual acuity in the evening was detected in 10.4% of eyes, changes in lens strength were observed in 10.4% of eyes, and decentration of optical strength was observed in 31.1% of eyes. Localized epithelial edema was detected in 5.5% of eyes, vacuole formation in the corneal epithelium was observed in 7.9% of eyes, and increased optical density of the superficial stromal layers was observed in 8.7% of eyes. Corneal microerosions were noted in 3.1% of eyes, and fluorescent staining of the cornea after wear was observed in 11.4% of eyes. After one year, keratitis developed in one eye (0.16%), and by 15 months, in both eyes (0.32%). The study found an optimal lens lifespan of 11.8±1.4 months (p=0.001). Keywords: orthokeratology lenses, cornea, keratitis, lens lifespan</jats:p>