title: Menicon Z rigid gas permeable lenses for keratoconus and irregular corneas: a retrospective case series.
abstract: OBJECTIVE
  The tisilfocon A (Menicon Z) rigid gas permeable (RGP) contact lens polymer has the highest oxygen permeability (Dk) value of any RGP lens material. To our knowledge there is no published literature documenting the success of this material in fitting contact lenses to highly irregular and diseased corneas.
  
  
  METHODS
  A retrospective medical record review of 40 consecutive patients (64 eyes) who had worn lenses made in the Menicon Z RGP material was performed. All patients had some form of corneal pathology and were fitted in a single tertiary care hospital-based contact lens service.
  
  
  RESULTS
  Menicon Z contact lenses were fit to 33 eyes of 20 patients with keratoconus (KC) and 31 eyes of 23 patients with irregular corneas. The irregular cornea group comprised 28 eyes of 21 patients after corneal surgery, 1 eye with ocular cicatricial pemphigoid and 2 eyes of 1 patient with chronic staphylococcal blepharo-keratoconjuncitivitis. Treatment goals included acceptable corneal physiology, comfort, and visual acuity. In the KC group, there was an 82% (27/33 eyes) success rate as measured by the treatment goals. Mean duration of wear for successful patients was 2.5 years (0.5-5 years). Only 12% (4/33 eyes) failed directly due to inability of the Menicon Z material to perform adequately while another material was acceptable. In the irregular surface group (surgical and ocular surface disease), there was a 74% (23/31 eyes) success rate. Mean duration of wear for successful patients in this group is 2.79 years (3 months-7 years). Only 3% (1/31 eyes) failed directly due to inability of the Menicon Z material to perform adequately while another material was acceptable.
  
  
  CONCLUSIONS
  The tisilfocon A hyper Dk lens material maintains clinically acceptable corneal health and clinically acceptable visual acuity for patients with KC and irregular corneal surfaces. In this series of patients with complicated corneal disease, the most failures were due to design issues and discomfort not related to the Menicon Z material. The Menicon Z material was inadequate in only 8% of eyes, whereas another RGP material was successful. Most patients with irregular corneas in a tertiary care center can be successfully fit with the tisilfocon A RGP material for visual rehabilitation.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University Hospitals Case Medical Center and Case Western Reserve University, Cleveland, OH 44106, USA. Loretta.szczotka@uhhospitals.org
authors.forename: Loretta B
authors.initials: LB
authors.lastname: Szczotka-Flynn
authors.forename: Shamil
authors.initials: S
authors.lastname: Patel
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003261:Contact Lenses; D003315:Cornea / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007640:Keratoconus / Q000473:pathology / Q000534:rehabilitation*; D008297:Male; D008768:Methylmethacrylates; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism; D017755:Prosthesis Fitting; D012189:Retrospective Studies; D012828:Silicones; D013997:Time Factors; D055815:Young Adult
chemical_list: D008768:Methylmethacrylates; D012828:Silicones; C041037:menicon O2; D010100:Oxygen