title: Medical applications and outcomes of bitangential scleral lenses.
abstract: OBJECTIVE
  To evaluate the clinical results of a new scleral lens design with a bitangential (nonrotationally symmetrical) periphery.
  
  
  METHODS
  All the necessary data were obtained during the 1-year study period. The bitangential scleral lenses were fitted and monitored according to a standardized fitting methodology. They were cut by precise submicron lathing from high-oxygen-permeable materials (including 10 scleral lenses from Menicon Z material). Subjective performance, visual acuity, and scleral lens-fitting characteristics were recorded after a median of 9.4 weeks (range, 3 weeks to 1 year).
  
  
  RESULTS
  Diagnoses in the 213 eyes (in 144 patients) were keratoconus (n = 121 eyes; 56.8%), ocular surface diseases (n = 31 eyes; 14.6%), penetrating keratoplasty (n = 29 eyes; 13.6%), and other forms of irregular astigmatism (n = 28 eyes; 13.1%). Many patients (164 lenses; 77.0%) gave high ratings for comfort. The most common diameter was 20.0 mm (162 lenses; 76.1%) (range, 18.5 to 21.5 mm). Median decimal best-corrected visual acuity with the bitangential scleral lenses was 0.8 (equivalent to Snellen 20/25) (range, 0 to 1.5). Most bitangential scleral lenses showed good fitting characteristics: optimal values were seen for lens movement (208 lenses; 97.7%) and lens position (208 lenses; 97.7%). Median central corneal clearance was 0.2 mm; clearances differed in the four peripheral directions. The median stabilization axis was 140 degrees (range, 0 to 180 degrees) in the right eyes and 60 degrees (range, 0 to 180 degrees) in the left eyes.
  
  
  CONCLUSIONS
  The bitangential scleral lens-fitting and performance characteristics were clear and effective for the health professional and the patient. The high-oxygen-permeable material Menicon Z may, in theory, be of benefit to corneas with a high oxygen demand.
authors: *MSc †MSc, PhD ‡BSc, FAAO §MD, PhD Visser Contact Lens Practice, Nijmegen, The Netherlands and the Department of Ophthalmology of the University Medical Center, Utrecht, The Netherlands (E-SV, HMO, RV); NKL Contactlenzen, Emmen, The Netherlands (BJJJVdL) and the Department of Ophthalmology of the University Medical Center Utrecht, The Netherlands (AVdL).
authors: Esther-Simone
authors: ES
authors: Visser
authors: Bart J J J
authors: BJ
authors: Van der Linden
authors: Henny M
authors: HM
authors: Otten
authors: Allegonda
authors: A
authors: Van der Lelij
authors: Rients
authors: R
authors: Visser
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D003261:Contact Lenses; D003316:Corneal Diseases / Q000503:physiopathology / Q000628:therapy*; D005260:Female; D006801:Humans; D015948:Keratoplasty, Penetrating; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction; D011474:Prosthesis Design; D017755:Prosthesis Fitting; D012590:Sclera; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult