A survey of corneal changes caused by daily wear silicone hydrogel contact lenses

Abstract

Purpose: The examination of the e®ects of second generation lotra¯lcon B silicone hydrogel (SiH) lenses on the cornea when worn for three years of daily wear. Material and Methods: 55 healthy patients were divided into two groups: current hydrogel contact lens wearers re¯tted with lotra¯lcon B lenses (Group 1; 28 patients) and neophyte contact lens wearers (Group 2; 27 patients). Each patient's subjective eye comfort was measured with a self-administered questionnaire. The corneas were analyzed using contact specular microscope to measure corneal thickness and the endothelium before the SiH lenses were¯tted after four weeks, one month, six months, one year, two years, and three years of lens wear. Results: Subjective complaints of patients in Group 1 were reduced; however patients in Group 2 experienced discomfort during thē rst two to four weeks of use. In Group 1, objective examinations identi¯ed a decrease in endothelial cell density. In Group 2, the endothelial cell density increased slightly in the¯rst two years but decreased after three years. The results indicate that lotra¯lcon B slows down the deleterious e®ects of contact lenses. The coe±cient of variation signi¯cantly decreased after six months in Group 1 (0.47 vs 0.44; p ¼ 0:049), whereas, in Group 2, the hexagonal cells improved signi¯cantly after one month (27.78 vs 28.25; p ¼ 0:025). Conclusion: Based on the subjects involved and the period of time under examination, it can be concluded that high-Dk SiH lenses support the physiological metabolism and functions of the cornea by improving oxygen provision.

Investigation of corneal changes in soft contact lens wearers

“…Korneal hipoksi ve stres; pleomorfizm, polimegatizm ve endotel hücre yoğunluğunun azalmasını tetikler. 20 Ketessy ve ark. hidrojel lens kullananlarda endotel sayısında istatistiksel anlamlı olmayan bir azalma bulmuşlardır.…”

“…Silikon hidrojel lens kullananlarda hücre yoğunluğunda ilk 1 ayda azalma sonrasında 2 yıla kadar artış ve 3. yılda tekrar azalma gözlemlemişlerdir. 20 Lotrafilcon B kullananlarda hekzagonal hücre yüzdesinde 1. ayda artış gözlemlenmiştir. Başka bir çalışmadada hücre dansitesi ve hekzagonal hücrelerin, 5 yıl üzeri kullanımda istatistiksel olarak anlamlı azaldığı görülmüştür.…”

Enhancing mechanical strength of hydrogels via IPN structure

“…Hydrogels with three‐dimensional networks were capable of absorbing large amounts of water, which were widely used in various applications including tissue scaffolds, drug delivery vehicles, cell supports, contact lenses, corneal implants, cartilage, etc. However, the applications of hydrogels were still limited by various factors such as the molecules structure or heterogeneous network structure.…”