title: [Light sensitivity in central visual field].
abstract: OBJECTIVE
  To examine the difference in the light sensitivity in the central visual field between the normal subjects and glaucoma patients with or without the early visual field damages and propose the criteria to identify the possible early disturbance in the visual field.
  
  
  METHODS
  The light sensitivity at the 76 locations in the central field was measured in 108 normal eyes of 75 normal volunteers aged from 20 to 78 years and 82 eyes of 53 patients with early open-angle or angle-closure glaucoma aged from 30 to 70 years on the Humphrey Field Analyzer (Model 610) by using the Central-30-2 program.
  
  
  RESULTS
  No sex and eye differences in the light sensitivity were found between the two groups. The significant difference in the light sensitivity existed between the age of 20 - 45 years and the age of 46 - 78 years in the normal subjects. The lower limit of 80% normal range for each location in the central field of the two age groups was calculated. The light sensitivity decreased by 2 - 3 dB at every 10 degree from the eccentricity. The light sensitivity in the inferior field was 1 - 2 dB higher than that in the superior. There was no statistical difference between the nasal and the temporal field. For the patients with the field defects the light sensitivity of many locations decreased by 4 - 8 dB, and by 1 or 2 dB in the patients without the field defects as compared with the normal control.
  
  
  CONCLUSIONS
  Based on the comparison with the normal control and the lower limit of 80% normal range, we propose the following criteria for classification of damages in the glaucoma visual field. Grade I: light sensitivity decreases by 1 - 3 dB at a cluster of locations in the field; Grade II: light sensitivity reduces by 4 - 6 dB at a cluster of locations in the field; Grade III: light sensitivity reduces by more than 6 dB at a cluster of locations in the filed.
authors.affiliation: Department of Ophthalmology, The 2nd Affiliated Hospital. Hunan University of Medical Sciences, Changsha 410011.
authors.forename: Z
authors.initials: Z
authors.lastname: Wu
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: Y
authors.initials: Y
authors.lastname: Jiang
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005901:Glaucoma / Q000175:diagnosis / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020795:Photophobia / Q000503:physiopathology*; D014794:Visual Fields