Association of intraocular pressure-related factors and retinal vessel diameter with optic disc rim area in subjects with and without primary open angle glaucoma

IMPORTANCE: The data may support the notion that the intra-ocular pressure (IOP)-related factors and vascular factors were implicated concurrently in glaucomatous optic nerve damage.

BACKGROUND: To study the association of intraocular pressure (IOP)-related factors, IOP, trans-lamina cribrosa pressure difference (TLCPD), cerebrospinal fluid pressure (CSFP) and retinal vessel diameters (RVD), central retinal arteriolar equivalent (CRAE), central retinal venular equivalent (CRVE) with neuro-retinal rim area (RA).

DESIGN: A population-based, cross-sectional study.

PARTICIPANTS: A total of 6830 people aged 30 years and over.

METHODS: All participants underwent a comprehensive eye examination, fundus photograph-based measurements of RVD and Heidelberg retinal tomogram (HRT) measurement of optic disc.

MAIN OUTCOME MEASURES: RA, CRAE, CRVE, IOP, body mass index (BMI), CSFP and TLCPD.

RESULTS: Primary open-angle glaucoma (POAG) was diagnosed using two separate methods: 67 from expert consensus, and 125 from the International Society of Geographical and Epidemiologic Ophthalmology (ISGEO) classification. After excluding of those with high myopia or without gradable HRT images, 4194 non-glaucoma and 40 POAG were analysed for determinants of RA. On multivariable analysis determinants of reduced RA were POAG (P < 0.001), higher IOP (P = 0.03), higher refractive error (P < 0.01), longer axial length (P = 0.01), CRVE (P < 0.001), lower BMI (P = 0.015), older age (P < 0.001) smaller disc area (P < 0.001) and higher TLCPD (P = 0.03). When age and/or BMI were omitted from the model, reduced RA was also associated with lower CSFP (P < 0.001).

CONCLUSIONS AND RELEVANCE: Reduced RA is associated with narrow CRVE and higher IOP or lower CSFP. The data supports the concurrent role of IOP-related and vascular factors in glaucomatous optic nerve damage.