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    Glaucoma

    Review of: Cardiovascular disease predicts structural and functional progression in early glaucoma

    Marshall H, Mullany S, Qassim A, et al. Ophthalmology, January 2021

    This prospective, longitudinal study assessed the association between cardiovascular disease and glaucoma.

    Study design

    Investigators evaluated 2,638 eyes for baseline and longitudinal structural thinning using spectral-domain OCT, and for visual field progression using Humphrey visual field (HVF) testing. At enrollment, patients were classified as having predominant thinning of the macular ganglion cell-inner plexiform layer (mGCIPL), the peripapillary retinal nerve fiber layer (pRNFL) or both. The mean follow-up was 5.34 years. The authors compared cardiovascular disease and medication use between the study patients and a reference group of structurally and functionally stable glaucoma suspects.

    Outcomes

    At baseline, patients with mGCIPL thinning had a higher prevalence of previous myocardial infarction (OR 5.14), hypertension (OR 2.70), antihypertensive medication use (OR 2.03) or statin use (OR 1.98). The prevalence of cardiovascular disease and medication use among patients with pRNFL thinning was comparable to controls.

    Longitudinal follow-up revealed that hypertension was associated with an increased risk of progression on both OCT (OR 1.79) and HVF (OR 1.92). In addition, an increase of 21 mm Hg (1 standard deviation) in systolic blood pressure at baseline was linked to increased risk of OCT progression (OR 1.27) and HVF progression (OR 1.32). Although the association between systolic blood pressure and structural progression was similar to the relationship between IOP and structural progression (OR 1.30), IOP was more strongly linked to HVF progression than systolic blood pressure (OR 1.52 vs. 1.32).

    Limitations

    It is not known whether structural changes on macular spectral-domain OCT are related to glaucoma, cardiovascular disease or both. Age-related macular changes—both pathologic and degenerative—may have contributed to the detected structural defects. In addition, the use of 24-2 HVF to assess progression could have missed a significant portion of macular defects that would be better detected with 10-2 perimetry.

    Clinical significance

    This study shows the important link between cardiovascular disease and structural and functional progression in early glaucoma. The relationship between blood pressure and IOP suggests the effect of hypertension on glaucoma progression may be partially mediated by IOP pathways, and that vascular pathways may be especially important in glaucomatous damage to the macula. This study underscores the need for mechanistic research to slow glaucoma progression in ways that do not rely solely on IOP reduction.