Efficacy of SLO-microperimetry and Humphrey for evaluating macular sensitivity changes in advanced glaucoma

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Objective: To compare the efficacy of scanning laser ophthalmoscope microperimetry (SLO-MP) and Humphrey visual fields in detecting macular sensitivity changes in advanced glaucoma.
Design: Prospective cohort study.
Participants: 25 patients with advanced primary open angle glaucoma and 2 consecutive abnormal Humphrey 10-2 SITA Standard visual field tests.
Methods: Thirty-six eyes of 25 patients with 2 consecutive abnormal Humphrey 10-2 SITA Standard (H10) visual fields were retested with a modified 10-2 SLO-MP within 3 months of the last reliable H10. A standardized grid was used to mark the macula. Primary outcome was change in mean macular sensitivity (dB; H10 and SLO-MP) in relation to mean macular retinal nerve fibre layer (RNFL) thickness (µm) by SLO- optical coherence tomography (SLO-OCT). Secondary outcome was comparison of reliability indices for both tests. Linear regression was used for analysis.
Results: Mean macular sensitivity was significantly lower in SLO-MP (9.33 ± 3.37 dB) than H10 (18.83 ± 6.46 dB; p < 0.0001). Mean macular RNFL thickness correlated significantly with retinal sensitivity by both SLO-MP (r = 0.39, p < 0.02) and H10 (r = 0.37, p < 0.03). Fixation losses were better controlled in SLO-MP (0.38 ± 1.1) than H10 (4.28 ± 7.9; p = 0.008). False-positive responses were similar (SLO-MP: 2.25 ± 4.53, H10: 1.78 ± 3.33; p = 0.80). A statistically significant difference was noted in the false-negative responses (SLO-MP: 26.87 ± 25.24, H10: 5.33 ± 9.70; p < 0.0001).
Conclusions: Macular sensitivity determined by both H10 and SLO-MP correlates significantly with mean macular RNFL thickness measured by SLO-OCT. Precise localization of the macula in SLO-MP results in lower fixation losses. Detection of denser field defects by SLO-MP results in higher false-negative responses. A larger sample size is needed to further study the value of this diagnostic tool.


This work was published before the author joined Aga Khan University.

Publication (Name of Journal)

Canadian Journal of Ophthalmology