title: Corneo-scleral contact lens in a piggyback system for keratoconus: A case report.
abstract: OBJECTIVE
  We describe a case of fitting a corneo-scleral contact lens with a multi-aspheric geometry design (MAGD CScL) on top of a daily silicone hydrogel lens (piggyback system) for keratoconus management.
  
  
  METHODS
  A 48-year-old man using soft toric contact lenses required an improvement in the unsatisfactory quality of his vision. He presented with bilateral asymmetric keratoconus with high myopia in the right eye (RE) and severe myopia in the left eye (LE). In addition, he had low vision in his LE because of a maculopathy. He was fitted with MAGD CScL to correct his irregular astigmatism. A diagnostic trial set was used in the fitting process and the patient was assessed according to a standardised fitting methodology. Visual acuity, corneal topography and contrast sensitivity were evaluated. The follow-up period was 1year.
  
  
  RESULTS
  The best spectacle-corrected visual acuity was 0.5 logMAR for the RE with -10 D/-5 D×60° and 2 logMAR for the LE with -20 D/-3 D×105°. After fitting MAGD CScL, visual acuity improved significantly to 0.1 logMAR for the RE and 1.3 logMAR for the LE, as well as contrast sensitivity. The fitting parameters of the base curve, diameter, and power were 7.05mm, 12.60mm, -18.50 D and 7.15mm, 12.60mm, -19 D for the RE and LE, respectively. Optimal fitting characteristics were found in terms of lens position and lens movement. To increase the time of MAGD CScL wear, they piggybacked on daily silicone hydrogel lenses of low power (-0.5 D). The patient reported being comfortable with this piggyback system for approximately 15h a day. After 1year of using the piggyback system, visual quality and wearing time were maintained. In addition, no adverse ocular effects were found during this period.
  
  
  CONCLUSIONS
  This case report shows that in this patient a MAGD CScL could be fitted successfully on a daily silicone hydrogel lens in a piggyback system for keratoconus management, providing good visual quality along with prolonged use times and without adverse effects on the cornea.
authors.affiliation: Department of Optics, Optometry and Vision Sciences, Physics College, University of Valencia, Burjassot, Valencia 46100, Spain. Electronic address: esteban.porcar@uv.es.
authors.forename: Esteban
authors.initials: E
authors.lastname: Porcar
authors.affiliation: Department of Optics, Optometry and Vision Sciences, Physics College, University of Valencia, Burjassot, Valencia 46100, Spain.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Montalt
authors.affiliation: Department of Surgery, Ophthalmology unit, La Fe University and Polytechnic Hospital, Faculty of Medicine and Odontology, University of Valencia, Hospital la Fe, Valencia 46026, Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: España-Gregori
authors.affiliation: FISABIO Oftalmología Médica (FOM), Cornea Unit and Anterior Segment Diseases, Catholic University of Valencia, Valencia 46015, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Peris-Martínez
mesh_terms: D003263:Contact Lenses, Hydrophilic; D015350:Contrast Sensitivity; D003315:Cornea; D004867:Equipment Design; D006801:Humans; D007640:Keratoconus / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D012590:Sclera; D014792:Visual Acuity
keywords: Corneal ectasia; Corneo-scleral contact lens; Keratoconus