title: Morphision: a method for subjective evaluation of metamorphopsia in patients with unilateral macular pathology (i.e., full thickness macular hole and epiretinal membrane).
abstract: BACKGROUND
  Lack of clinical tests to quantify spatial components of distortion in patients with full thickness macular holes (FTMH) and epiretinal membranes (ERM).
  
  
  OBJECTIVE
  To develop a test for subjective evaluation of visual distortion in the central visual field around fixation in patients with unilateral FTMH or ERM.
  
  
  METHODS
  Prospective case-control study carried out at tertiary referral center.
  
  
  METHODS
  Twenty-five patients with unilateral macular disease (13 macular epiretinal membranes, 12 full-thickness macular holes), and nine controls (without ocular pathology) underwent ophthalmological examination with logMAR ETDRS visual acuity, near vision and contrast sensitivity assessed. Macular optical coherence tomography and metamorphopsia assessment using Morphision test was also carried out. This test consists of a set of modified Amsler charts for detection, identification, and subjective quantification of visual distortion in the central visual field around fixation. Morphision test content and construct validity, and reliability (test-retest method) were evaluated. Sixteen patients completed an unstructured survey on test performance and preference.
  
  
  RESULTS
  Every patient with unilateral FTMH or ERM identified a particular chart using Morphision test (content validity). None of the normal subjects without symptoms of metamorphopsia identified any distortion (construct validity). Test-retest showed a 100% consistency for frequency and 67% for amplitude. The mean amplitude difference between measurements was 0.02 degrees (SD = 0.038). The coefficient of repeatability was 0.075. There was a correlation between Morphision amplitude score and visual acuity and contrast sensitivity, individually.
  
  
  CONCLUSIONS
  Morphision test allowed detection and subjective quantification of metamorphopsia in the clinical setting in our patients with unilateral macular epiretinal membranes and full thickness macular holes.
authors.forename: Marta
authors.initials: M
authors.lastname: Ugarte
authors.forename: Manoharan
authors.initials: M
authors.lastname: Shunmugam
authors.forename: D Alistair H
authors.initials: DA
authors.lastname: Laidlaw
authors.affiliation: St. Thomas' Hospital, Lambeth Palace Road, London, SE1 7EH, United Kingdom.
authors.forename: Tom H
authors.initials: TH
authors.lastname: Williamson
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D019773:Epiretinal Membrane / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008266:Macula Lutea / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012167:Retinal Perforations / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D041623:Tomography, Optical Coherence; D014786:Vision Disorders / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D014792:Visual Acuity