Abstract
Purpose: :
To determine the relationship of retinal vascular caliber with glaucoma subtypes in Asians.
Methods: :
This was a cross-sectional hospital-based study of 411 persons with glaucoma, who were prospectively recruited and underwent dilated digital retinal photography and standardized clinical assessment. Primary open angle glaucoma (POAG) patients with a mean intraocular pressure (IOP) without treatment that was consistently less than 21 mm Hg on diurnal testing were classified as normal tension glaucoma (NTG), and those with higher IOP were classified as high tension glaucoma (HTG). Primary angle closure glaucoma (PACG) subjects had at least 180 degrees of angle closure on gonioscopy. Retinal vascular caliber was measured by a computer-assisted software in a zone 0.5 to 1.0 disc diameter away from optic disc, and summarized as average retinal arteriolar and venular caliber of that eye. Right eye retinal vascular caliber was used for analyses.
Results: :
276 POAG subjects (138 HTG and 138 NTG subjects) and 135 PACG subjects were studied. Retinal venular caliber was narrower in persons with POAG (age, gender adjusted 205.2 ± 1.6 µm) compared to PACG (214.1 ± 2.2 µm) (p=0.001). Within the POAG group, there was no difference in venular caliber between HTG (204.1 ± 2.2 µm) and NTG (206.2 ± 2.1 µm). After adjusting for age, gender, axial length, hypertension and diabetes, persons with POAG (odds ratio [OR] 3.1, 95% CI, 1.6, 6.2, narrowest vs widest venular caliber) had narrower venular caliber than persons with PACG. Persons with either HTG (OR 4.4, 95% CI, 2.0, 9.7) or NTG (OR 2.4, 95% CI, 1.1, 5.1) had narrower venular caliber than persons with PACG. Retinal arteriolar caliber did not differ between glaucoma sub-types.
Conclusions: :
POAG eyes have narrower retinal venular caliber than PACG. This supports the greater contribution of microvascular processes in POAG as compared to PACG. An assessment of retinal vascular caliber may provide further insights into the "vascular etiology" of glaucoma subtypes.
Keywords: clinical (human) or epidemiologic studies: natural history • clinical (human) or epidemiologic studies: risk factor assessment