title: [Comparison of local differential luminance sensitivity (dls) between Oculus Twinfield Perimeter and Humphrey Field Analyzer 630 (HFA I) in normal volunteers of varying ages].
abstract: OBJECTIVE
  Purpose of this study was to compare age-corrected normal values of differential luminance sensitivity (dls) of the Oculus Twinfield Perimeter with those of the Humphrey Field Analyzer 630 (HFA I). Furthermore, naso-temporal and superior-inferior asymmetries in the central visual field were analyzed.
  
  
  METHODS
  72 ophthalmologically normal volunteers, 12 per decade, were examined with both perimeters using a 4-2 dB bracketing strategy with two reversals for threshold estimation. A biometric model, which fits a hill of vision to the data, was developed. The age-related hills, created by the model, were compared between the instruments and analyzed for asymmetries.
  
  
  RESULTS
  The normal dls values for the Twinfield perimeter were about 1.5 dB above those of the HFA I. The shape of the hill in regard to slope in corresponding locations did not differ substantially. The decline of local differential luminance sensitivity showed a nonlinear correlation to age: it remained almost constant up to the 4th decade, with a steeper decline beyond that age. A naso-temporal as well as a superior-inferior asymmetry was found. Along the vertical meridian, the slope of the hill was steeper in the superior part than in the inferior. At an excentricity of 20 degrees we found a superior-inferior difference of 2.1 dB for the HFA and of 1.8 dB for the Twinfield perimeter benefitting the inferior meridian. Along the horizontal meridian there was a distinct difference in regard to the shape of the hill. The sensitivity was greater in the temporal half of the visual field than in the nasal. At an excentricity of 30 degrees, the difference was about 2.75 dB for the HFA and 2.5 dB for the Twinfield perimeter. These asymmetries seem to appear in all age groups. Unfortunately, the exact influence of age on the appearing asymmetries cannot be quantified by the used model.
  
  
  CONCLUSIONS
  The normal dls values benefit the Twinfield for about 1.5 dB compared to the HFA. There seems to be a critical age of about 40 - 50 years, beyond which a decline of dls becomes manifest.
authors.affiliation: Abteilung II, Universitäts-Augenklinik Tübingen.
authors.forename: L
authors.initials: L
authors.lastname: Lorch
authors.forename: T J
authors.initials: TJ
authors.lastname: Dietrich
authors.forename: R
authors.initials: R
authors.lastname: Schwabe
authors.forename: U
authors.initials: U
authors.lastname: Schiefer
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011786:Quality Control; D012016:Reference Values; D012684:Sensory Thresholds; D058609:Visual Field Tests / Q000295:instrumentation*