Study Details Potential Structures Useful in Monitoring Severe Glaucoma

When examining the structural parameters of patients with advanced and severe glaucoma, a study published in the American Journal of Ophthalmology suggests both superficial and deep macular vessel densities (VD) have a better correlation with VA than other structural parameters. However, in patients with severe glaucoma, only deep nasal grid VD was linked to acuity. Therefore, they conclude that examining deep nasal grid VD in patients with late-stage glaucoma may be beneficial.

Conducting objective structural and subjective functional exams are necessary to assess and manage patients with glaucoma. While there is usually a correlation between visual field and optical coherence tomography (OCT) measurements in patients with early glaucoma, those measurements for patients in the later stages of the disease may reach the measurement floor.

To evaluate the correlation between structural parameters and VA in patients with advanced glaucoma, investigators formed 2 groups from 238 patients (238 eyes). In total, the population included 82 men aged 59.9±13.8 years. Group 1 had advanced glaucoma (mean deviation of 24-2 visual field tests from -12.01 to -20.0 dB), while Group 2 had severe glaucoma (<-20 dB).

In the advanced glaucoma group of 133 eyes, superficial (P <.001) and deep macular VD (P <.001) showed the highest correlation with VA. The areas under the receiver operating characteristic (AUROCs) of the superficial parafoveal/macular VDs were 0.816 (0.735–0.897) and 0.808 (0.725–0.891), respectively. In the severe glaucoma group of 105 eyes, deep nasal grid VD (γ=-0.31, P =.002; γ=-0.35, P <.001) showed the highest correlation with VA. Deep macular VD was more strongly correlated with VA than other structural parameters, according to researchers. The AUROCs of deep macular VD and deep nasal grid VD were 0.740 (0.632–0.849) and 0.748 (0.640–0.857), respectively.

The study’s authors note several limitations with their work, including test-retest variability. In addition, several factors may affect VD analysis, such as subclinical age-related macular degeneration, aging, diabetes mellitus, hypertension, systemic vasoactive medication, and glaucoma drops. Further, investigators report that projection artifacts of superficial vessel patterns on scans of the deep retinal layer may bias the analysis of deep macular VD. Lastly, the study only included patients with macular degeneration of <-12 dB, and patients were not classified by glaucoma types.

Reference

Hsia Y, Wang TH, Huang JY, et al. Relationship between macular microvasculature and visual acuity in advanced and severe glaucoma: macular microvasculature and visual acuity. Am J Ophthalmol. Published online October 12, 2021. doi:10.1016/j.ajo.2021.10.005