Evaluation of the Effect of N-Acetylcysteine on Protein Deposition on Contact Lenses in Patients with the Boston Keratoprosthesis Type I

Purpose: To establish the efficacy of topical N-acetylcysteine (NAC) as a treatment to reduce protein deposition on the contact lens surface. Methods: In this prospective, nonrandomized clinical trial, a total of 10 eyes (9 patients) were enrolled from a single center. All patients had a prior ocular history of either a Boston Keratoprosthesis type I or trichiasis from Stevens-Johnson syndrome, which necessitated full-time contact lens wear. Four visits were required to complete the study. During visit 1, a new contact lens was inserted and a baseline examination was performed. Visit 2 served as the control month, whereas visits 3 and 4 were month 1 and 2 on treatment with 20% NAC. At the end of each visit the contact lens was replaced. The lenses from visit 2 (control monthwithout NAC) and from visit 3 (treatment monthwith NAC) were collected for proteomic analysis. The main outcome measures were to quantify protein deposition, as well as to assess the visual acuity and ocular surface symptoms before and after treatment. Results: Topical NAC resulted in a 20% decrease in protein deposition. This correlated with a trend for improvement in visual acuity and increased subjective improvement in vision at month 1 (P=0.0153) and 2 (P=0.0016). Conclusions: NAC reduced protein deposition, decreased ocular surface symptoms, and improved contact lens transparency, thereby providing increased optical clarity.