Comparing Glaucoma Progression on 24-2 and 10-2 Visual Field Examinations

Abstract

PurposeTo compare the rate of mean deviation (MD) change on 24-2 versus 10-2 VFs in treated glaucomatous eyes with 5 or more examinations.MethodsIn a retrospective study, 24-2 and 10-2 VFs of 131 glaucoma patients (167 eyes) who had undergone at least 5 VFs examinations during their follow-up were analyzed. All these patients had VF defects both on 24-2 and 10-2 VFs. Rates of MD change were calculated using best linear unbiased predictions (BLUP).ResultsMedian age, MD on 24-2 VF at baseline, number of VFs performed during follow-up and follow-up duration were 55 years, -16.9 dB, 9 and 9 years respectively. Median rate of MD change was significantly greater (p<0.001) on 10-2 VF (-0.26 dB/year; interquartile range [IQR]: -0.47, -0.11) compared to 24-2 VFs (-0.19 dB/year; IQR: -0.41, -0.03). Comparing the rates of MD change in eyes with different severities of VF loss (early [MD better than -6 dB], moderate [-6 dB to -12 dB], advanced [-12 to -20 dB] and severe [MD worse than -20 dB]) at baseline (based on the MD on 24-2 VF), median rate of MD change was comparable between 10-2 and 24-2 VFs in mild (-0.45 dB/year vs. -0.40 dB/year, P = 0.42) and moderate (-0.32 dB/year vs. -0.40 dB/year, P = 0.26) VF loss categories, while the same were significantly greater on 10-2 VFs in advanced (-0.28 dB/year vs. -0.21 dB/year, P = 0.04) and severe (-0.18 dB/year vs. -0.06 dB/year, P<0.001) VF loss categories.ConclusionsIn patients with VF defects both on 24-2 and 10-2 VFs, evaluating the rate of MD change on 10-2 VFs may help in better estimation of glaucoma progression, especially so in eyes with advanced glaucoma at baseline.

Comparison of Rates of Fast and Catastrophic Visual Field Loss in Three Glaucoma Subtypes

“…This is consistent with the observation that baseline MD does not profoundly affect rate of visual field progression, 3,24 although floor effects will likely slow measured progression rates in those with advanced field loss. 24…”

“…Our results show that the overall visual field progression rates for our cohort were similar to what has been reported from a Canadian tertiary care setting. 3 Our median rate of visual field loss was just outside the interquartile range (IQR) previously reported by Rao et al 24 for an Indian population (À0.19 dB/y: IQR À0.41, À0.03) and so is likely within the 95% CI (unreported) for their data, despite their cohort having a substantially greater median MD at baseline (À16.9 vs. À4.42). This is consistent with the observation that baseline MD does not profoundly affect rate of visual field progression, 3,24 although floor effects will likely slow measured progression rates in those with advanced field loss.…”

Comparison of Glaucoma Progression Detection by Optical Coherence Tomography and Visual Field

“…Thus the monitoring of glaucoma progression in very advanced stages remains a challenge that could benefit from new solutions. 56 In this study we did not require that changes were confirmed on subsequent testing, in order to increase sensitivity. 57 This does not affect our conclusions, since the same methodology was applied to both VF and OCT trend analysis.…”

Measuring Rates of Visual Field Progression in Linear Versus Nonlinear Scales: Implications for Understanding the Relationship Between Baseline Damage and Target Rates of Glaucoma Progression

“…7,8 Other studies, however, have shown that a worse baseline MD is associated with faster rates of progression in dB/year, 9,10 while another found the opposite. 11 There are numerous factors that may help explain such differences, including differences in population sampling and the effects of treatment. 8 This is further complicated by the use of a logarithmic scale (dB) to define the level of baseline damage and applying linear regression to measure the slopes of progression.…”