Efficacy and Safety of cleadewGP for Rigid Contact Lenses
Condition: Contact Lens Solution Toxicity
Study type: Interventional

Summary: 
      Multipurpose solutions (MPS) are the most commonly prescribed regimen to clean, disinfect and
      rinse rigid lenses. The preservatives used in MPS may cause hypersensitivity and the presence
      of quaternary ammonium compounds (QAC) may increase development of antiseptic resistance
      mediated by QAC resistance genes, thus lowering the efficacy of disinfection. Povidone-iodine
      (PVI) has been safely used as a disinfectant for ophthalmic operations and eye drops. The
      cleadew GP (Ophtecs, Japan) tested in the current study is a PVI based rigid lens
      disinfecting solutions which does not employ QAC. If its efficacy and safety can be confirmed
      in this study, it will be a good alternative rigid lens care regimen for children.
    

Detailed description: 
      Multipurpose solutions (MPS) are the most commonly prescribed regimen to clean, disinfect and
      rinse rigid lenses. These solutions usually contain quaternary ammonium compounds (QAC) which
      have been shown to be selective for carriage of organisms harbouring QAC genes in
      orthokeratology (ortho-k) lens wear and it raises concerns about safety with the increasing
      popularity of orthokeratology (ortho-k) for myopia control in children. Hydrogen peroxide
      system is a good alternative but this option is limited in rigid lens market. The only brand
      available in Hong Kong labelled as safe for rigid contact lenses has limited disinfecting
      power. cleadewGP (Ophtecs, Japan) is a new disinfecting solution for rigid contact lenses
      which does not employ QAC and instead is povidone iodine (PVI) based. PVI has been safely
      used as a disinfectant for ophthalmic operations and is commonly used in eye drops. PVI-based
      soft and rigid lens solutions have been reported to be as effective against Pseudomonas
      aeruginosa as other MPS and hydrogen peroxide-based solutions. However, other efficacy
      against other organisms need to be demonstrated to allow this solution to meet FDA
      requirements. The PVI-based soft lens solution was also reported to be effective against
      Acanthamoeba. cleadewGP is relatively new in the market and not much work has been done on
      the efficacy and safety of this solution. If confirmed to be effective and safe, cleadewGP
      may be a better alternative to ortho-k lens wearers who need to use disinfecting solutions at
      least for a few years while under ortho-k treatment. In the absence of QAC, there will be no
      concern of selection of carriage of organisms harbouring QAC genes in ortho-k lens wearers
      using this disinfecting solution over time.

      The current study aims at investigating the effectiveness and safety of the cleadewGP for
      cleaning (lipid and protein removal) and disinfecting of ortho-k lenses by comparing the
      outcomes collected from subjects randomly assigned to one of the following study groups.

      Group 1: cleadewGP without lens rubbing Group 2: cleadewGP with lens rubbing Group 3:
      cleadewGP with separate daily cleaner Group 4: cleadewGP with separate daily cleaner and
      weekly protein removal agent

      Four study visits will be involved in this 6 months study: baseline, 1-month, 3-month, and
      6-month after lens wear. Complimentary solutions will be provided during the study period.
      Solutions and accessories will be replaced at monthly interval. Effectiveness for cleaning
      and disinfection and safety of lens wear will be determined by comparing the changes in
      ocular microbiome before and after lens wear, contamination levels of lenses and accessories,
      biomicroscopic examination of lenses and eyes, and subjective rating of lens comfort among
      the four groups of subjects.
    

Intervention name(s): OPHTECS cleadew GP
Intervention type(s): Device
Intervention description(s): Povidone-iodine based disinfecting solutions for rigid contact lenses
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment