title: Effect of refractive correction on the accuracy of frequency-doubling technology Matrix.
abstract: OBJECTIVE
  To investigate the effect of refractive correction on the reliability and accuracy of frequency-doubling technology (FDT) Matrix examinations.
  
  
  METHODS
  Forty-eight eyes of healthy people were submitted to the FDT Matrix 30/2 threshold program. They had experience in perimetry, normal eye examination, and negative history for glaucoma and/or neurological diseases. The subjects were randomized into groups A (24 subjects) and B (24 subjects). The FDT Matrix 30/2 examinations were carried out in 3 different sessions. At the first session, groups A and B underwent the examinations with their best refractive correction. In the second session, group A underwent the FDT 30/2 examination with best refractive correction and the group B without it. In the third session, the groups were matched and followed the same protocol. The perimetric and reliability indexes and the time of examination with or without correction were considered. The Student t test was used when the distribution of the data was normal, whereas Mann-Whitney when the distribution of the data was not normal. After a Bonferroni correction, a P value <0.001 was considered as statistically significant.
  
  
  RESULTS
  Mean deviation reduced statistically significantly when refractive correction was used (-2.65±3.71 vs. -1.41±3.51 dB; P<0.006). All the other perimetric indexes and data considered did not change significantly when the subjects did the examination with or without the refractive correction.
  
  
  CONCLUSIONS
  The statistically significant reduction of mean deviation obtained with corrective lens showed that a better general accuracy and reliability of FDT responses was obtained with refractive correction. Pattern standard deviation constancy with or without correction confirmed that a localized defect is the first sign of visual field defect and that the absence of differences of pattern standard deviation between the 2 sessions is related to the absence of pathologic conditions in the eyes studied. Finally, as FDT Matrix is less influenced by other nonconventional perimetric techniques by refractive errors, the use of corrective lens is advisable to improve the accuracy and reliability of the results obtained and to optimize their performance.
authors: Department of Ophthalmology, St Andrea Hospital, University Sapienza, Rome, Italy.
authors: Maria T
authors: MT
authors: Contestabile
authors: Andrea
authors: A
authors: Perdicchi
authors: Stefano
authors: S
authors: Amodeo
authors: Lorenzo
authors: L
authors: Paffetti
authors: Michele
authors: M
authors: Iester
authors: Santi M
authors: SM
authors: Recupero
mesh_terms: D000328:Adult; D005139:Eyeglasses; D005260:Female; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D012030:Refractive Errors / Q000628:therapy*; D015203:Reproducibility of Results; D012165:Retinal Ganglion Cells / Q000473:pathology*; D014065:Tonometry, Ocular; D014786:Vision Disorders / Q000175:diagnosis*; D014792:Visual Acuity / Q000502:physiology; D058609:Visual Field Tests; D014794:Visual Fields