To compare scanning laser polarimetry (SLP) measurements of retinal nerve fibe r layer (RNFL) thickness in perimetrically unaffected eyes of glaucoma patients with those in their fellow eyes with field loss and eyes of healthy subjects. Ob servational case-control study. Twenty-three glaucoma patients with a reproduc ible visual field (VF) defect in one eye (mean mean deviation, -5.71 decibels] ) and a normal VF in the other one (i.e., ≤1 VF test point below the 5%probabi lity levelan MD, -0.01 dB]) and 73 control eyes of as many agematched healthy subjects (mean MD, 0.39 dB). The MDs and pattern standard deviations of the glau coma patients’ eyes with normal VFs and the control eyes did not statistically s ignifi-cantly differ (independent samples t test, P = 0.15 and P = 0.61, respec tively). All subjects were measured in both eyes with the GDxVCC, a commercially available instrument featuring SLP with automated variable corneal compensation . Standard automated perimetrywas assessed by means of the Humphrey Field Analyz er (24-2 Full Threshold or Swedishinteractive threshold algorithm Standard achr omatic test program). The standard GDxVCC parameters TSNIT (temporal, superior, nasal, inferior, temporal) Average, Superior Average, Inferior Average, TSNIT St d. Dev., and Nerve Fiber Indicator (NFI) were determined. We also assessed the t hickness values in 6 parapapillary sectors. In addition, we calculated the propo rtion of eyes per group with an NFI of < 40. GDxVCC measurements showed more RNF L thinning in the perimetrically unaffected eyes of glaucoma patients than in th e healthy control eyes. The RNFL in the perimetrically unaffected eyes of glauco ma patients was thicker than that in their felloweyeswith field loss. TheNFI had a value of <40 in 11 of 23 (47.8%) perimetrically unaffected eyes of glaucoma patients, 19 of 23 (82.6%) eyes with VF loss of glaucoma patients, and 3 of 73 (4.1%) healthy control eyes. With the GDxVCC, thinning of the RNFL may be detec ted in perimetrically unaffected eyes of glaucoma patients with field loss in th eir fellow eyes. (c) 2004 by the American Academy of Ophthalmology. u001a To compare scanning laser polarimetry (SLP) measurements of retinal nerve fibr r layer (RNFL) thickness in perimetrically unaffected eyes of glaucoma patients with those in their fellow eyes with field loss and eyes of healthy subjects. Ob servational case-control study. Twenty- Three glaucoma patients with a reproduc ible visual field (VF) defect in one eye (mean mean deviation, -5.71 decibels)) and a normal VF in the other one (ie, ≤1 VF test point below the 5% probabiity levelan MD , -0.01 dB]) and 73 control eyes of as many agematched healthy subjects (mean MD, 0.39 dB). The MDs and pattern standard deviations of glau coma patients’ eyes with normal VFs and the control eyes did not statistically s ignifi- cantly differ (independent samples t test, P = 0.15 and P = 0.61, respec tively). All subjects were measured in both eyes with the GDxVCC, a commercially available instrument featuring SLP with automated variable corneal compensation. ed by means of the Humphrey Field Analyzer (24-2 Full Threshold or Swedishinteractive threshold algorithm Standard achrmatic test program). The standard GDxVCC parameters TSNIT (temporal, superior, nasal, inferior, temporal) Average, Superior Average, Inferior Average, We also evaluate the t hickness values ​​in 6 parapapillary sectors. In addition, we calculated the propo rtion of eyes per group with an NFI of <40. GDxVCC measurements showed RNF L thinning in the perimetrically unaffected eyes of glaucoma patients than in th e healthy control eyes. The RNFL in the perimetrically unaffected eyes of glauco ma patients was thicker than that in their felloweyeswith field loss. TheNFI had a value of <40 in With the loss of glaucoma patients, 19 of 23 (82.6%) eyes with VF loss of glaucoma patients, and 3 of 73 (4.1%) of healthy control eyes. With the GDxVCC, thinning of the RNFL may be d etec ted in perimetrically unaffected eyes of glaucoma patients with field loss in th eir fellow eyes. (c) 2004 by the American Academy of Ophthalmology. u001a