title: Clinical applicability of the Macular Degeneration Detection Device (MDD-2): a novel photostress recovery measurement device.
abstract: BACKGROUND
  Diseases affecting the macula, such as age-related macular degeneration (AMD), diabetic retinopathy and central serous retinopathy can result in impaired photostress recovery time (PSRT) despite normal visual acuity and fundoscopic appearance. The MDD-2 Macular Degeneration Detection Device is a novel flash photostress recovery device. In this study, we examine the repeatability of the MDD-2 in a normal population and its suitability for incorporation into routine clinical practice.
  
  
  METHODS
  One hundred (60 female) subjects (mean age 35 ± 8 years; range 18 to 66 years) were recruited to partake in this study. The photostress recovery time was measured using the MDD-2 on three occasions in the dominant eye and one final occasion in the non-dominant eye to assess measurement repeatability. All subjects were in good ocular health. Visual acuity and iris colour were recorded for each participant.
  
  
  RESULTS
  Repeated measures analysis of variance revealed a statistically significant learning effect on intra-measurement repeatability (p < 0.01). Although paired t-test analysis revealed statistically significant differences between repeated measures both within and between eyes (p < 0.05 for all) the correlation between repeat measurements is statistically significant (p < 0.05 for all), and the coefficient of repeatability reaches clinically acceptable levels once the initial photostress recovery time, which demonstrated increased variability and latency compared to all subsequent measures, is excluded.
  
  
  CONCLUSIONS
  The MDD-2 provides highly repeatable measurements of photostress recovery time among young naïve subjects, following verbal explanation of the task and only one 'practise' measurement. The measurement is also highly repeatable between eyes, providing a potential immediate clinical biomarker of ocular health.
authors.affiliation: Optometry Department, College of Sciences & Health, Dublin Institute of Technology, Dublin, Ireland. james.loughman@dit.ie
authors.forename: James
authors.initials: J
authors.lastname: Loughman
authors.forename: Ciara
authors.initials: C
authors.lastname: Hewitt
authors.forename: Claire
authors.initials: C
authors.lastname: Judge
authors.forename: Louise
authors.initials: L
authors.lastname: Martin
authors.forename: Claire
authors.initials: C
authors.lastname: Moulds
authors.forename: Peter A
authors.initials: PA
authors.lastname: Davison
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D005260:Female; D006801:Humans; D008268:Macular Degeneration / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D020127:Recovery of Function