The research proves that coating orthokeratology lenses with NVP and PEGMA using PECVD enables long-lasting hydrophilicity and an effective reduction in protein adsorption, indicating a promising method for improving the biological compatibility and performance of such lenses.

Plasma-enhanced chemical vapor deposition (PECVD) is a vacuum plasma treatment procedure for the deposition of thin film on a substance, which was first used on orthokeratology lenses (ortho-k lenses) in order to coat polymerized 1-vinyl-2-pyrrolidinone (NVP) and poly(ethylene glycol) methacrylate (PEGMA) on the lenses. First, the surface of ortho-k lenses was pretreated with electrons, radicals, and peroxides for 9 min, under 9 sccm Ar, 36 sccm O2, and 120 W of applied radio frequency (RF) power. NVP and PEGMA were deposited on the surface of lenses through the heating of NVP to 50°C and PEGMA to 43°C. The chamber pressure was maintained at 300 mTorr, with 40 W of applied RF power, 12 sccm Ar, and an 8-cm treatment distance.