Contrast Sensitivity Perimetry and Clinical Measures of Glaucomatous Damage

Abstract

PurposeTo compare conventional structural and functional measures of glaucomatous damage with a new functional measure—contrast sensitivity perimetry (CSP-2).MethodsOne eye each was tested for 51 patients with glaucoma and 62 age-similar control subjects using CSP-2, size III 24-2 conventional automated perimetry (CAP), 24-2 frequency-doubling perimetry (FDP), and retinal nerve fiber layer (RNFL) thickness. For superior temporal (ST) and inferior temporal (IT) optic disc sectors, defect depth was computed as amount below mean normal, in log units. Bland-Altman analysis was used to assess agreement on defect depth, using limits of agreement and three indices: intercept, slope, and mean difference. A criterion of p < 0.0014 for significance used Bonferroni correction.ResultsContrast sensitivity perimetry-2 and FDP were in agreement for both sectors. Normal variability was lower for CSP-2 than for CAP and FDP (F > 1.69, p < 0.02), and Bland-Altman limits of agreement for patient data were consistent with variability of control subjects (mean difference, −0.01 log units; SD, 0.11 log units). Intercepts for IT indicated that CSP-2 and FDP were below mean normal when CAP was at mean normal (t > 4, p < 0.0005). Slopes indicated that, as sector damage became more severe, CAP defects for IT and ST deepened more rapidly than CSP-2 defects (t > 4.3, p < 0.0005) and RNFL defects for ST deepened more slowly than for CSP, FDP, and CAP. Mean differences indicated that FDP defects for ST and IT were on average deeper than RNFL defects, as were CSP-2 defects for ST (t > 4.9, p < 0.0001).ConclusionsContrast sensitivity perimetry-2 and FDP defects were deeper than CAP defects in optic disc sectors with mild damage and revealed greater residual function in sectors with severe damage. The discordance between different measures of glaucomatous damage can be accounted for by variability in people free of disease.

Individual differences in the shape of the nasal visual field

“…These volunteers were experienced and reliable on perimetric testing (Marin-Franch and Swanson 2013, Swanson, Malinovsky et al 2014). …”

“…These volunteers ranged in age from 46 to 84 yrs, median 67 yrs (63 ± 11 yrs) and participated in CSP testing from 2 to 10 times, median 7 tests (6.1 ± 2.5 tests). Details of these methods are available elsewhere (Swanson, Malinovsky et al 2014). …”

“…Initially a 40 cm test distance was used (Hot, Dul et al 2008), and this was later replaced by a 33 cm test distance (Swanson, Malinovsky et al 2014). The details of stimulus display, calibration, fixation monitoring, refractive correction for ametropia and test distance, stimulus configuration, test protocol and threshold algorithm for the CSP testing are available elsewhere (Hot, Dul et al 2008, Horner, Dul et al 2013, Swanson, Malinovsky et al 2014). …”

“…This is referred to as “CSP-2,” and is described in detail elsewhere (Swanson, Malinovsky et al 2014). This was used with the subset of 24 volunteers tested with alternate forms of perimetry.…”

Choice of Stimulus Range and Size Can Reduce Test-Retest Variability in Glaucomatous Visual Field Defects

“…Sixty-two patients with glaucoma and 41 agesimilar control subjects free of eye disease were tested as part of a multicenter longitudinal study 30 in three cities: Bloomington and Indianapolis, Indiana (Indiana University School of Optometry) and New York City, New York (SUNY College of Optometry). Experiment 1 tested 20 glaucoma patients ages 46 to 84 years (mean 62.8, SD 10.4) and 10 age-similar control subjects ages 47 to 77 years (mean 57.2, SD 8.1).…”