After informed consent was obtained, the participants underwent a complete ophthalmic examination, including visual acuity (VA) measurement, refraction, and slit lamp examination, as detailed elsewhere.
14 Three measurements of IOP were obtained by Goldmann applanation tonometry (Haag-Streit, Bern, Switzerland) and averaged to yield a single value for each eye.
In addition, an interviewer-administered questionnaire was used to obtain demographic, ocular, and medical histories. Information pertinent to this study included a history of cardiovascular disease including a history of angina, myocardial infarction, heart failure, and cerebrovascular accident. Participants were asked whether they had a history of glaucoma and whether they had been (or were currently being) treated with medications or laser or incisional surgery. Participants were also asked whether they had been told by a physician that they had elevated BP and were being treated for it, including the use of BP-lowering medications.
BP was measured by random zero sphygmomanometer with the participant in the sitting position. Two consecutive measurements of systolic and diastolic BP were obtained, and the average was used in the analysis. Hypertension was defined as systolic BP ≥140 mm Hg and/or diastolic BP (DBP) ≥90 mm Hg and/or current antihypertension therapy. Borderline hypertension was defined as SBP between 120 and 140 and/or DBP between 80 and 90. Hypotension was defined as SBP ≤90 and/or DBP ≤60. Mean arterial BP (MABP) was defined as ⅓SBP + ⅔DBP. Systolic, diastolic, and mean PPs were defined as systolic, or diastolic or mean arterial blood pressure minus IOP, respectively.
The criteria for diagnosing glaucoma in LALES are described in detail elsewhere.
15 In brief, definite OAG was defined as the presence of an open angle, with evidence of characteristic or compatible glaucomatous optic nerve damage on stereoscopic fundus photography and congruent, characteristic, or compatible glaucomatous visual field (VF) in at least one eye of a participant. Probable OAG was defined as the presence of an open angle and one of the following four criteria: (1) end-stage disease with VA of ≤20/200 and a cup–disc ratio of 1.0, with absence of VF data; (2) at least one abnormal VF test result with characteristic/compatible glaucomatous VF defects and no evidence of optic disc damage; (3) characteristic/compatible glaucomatous optic disc damage with no evidence of VF abnormality; and (4) other combinations of VF (lack of perfect congruence between the two or three VFs) and optic disc abnormalities that are both compatible with glaucomatous damage. The IOP level was not considered in establishing the diagnosis of OAG, and, thus, no differentiation was made between low- and high-tension OAG. Two glaucoma specialists used a stereoscopic viewer (Asahi viewer; Pentax, Englewood, CO) to examine simultaneous stereoscopic optic disc photographs and characterize optic nerve findings in terms of vertical and horizontal cup-disc ratios, cup-disc ratio asymmetry between the two eyes, disc and peripapillary nerve fiber layer hemorrhage, peripapillary atrophy, diffuse thinning of the neural rim (remaining neural rim <0.1), and notching of the neural rim (remaining neural rim in a localized area <0.1). Glaucomatous optic nerve damage was classified as characteristic if it met two or more of the following criteria and compatible if it met one of the following: horizontal or vertical cup-disc ratio ≥0.8, notching of the neural rim, localized or diffuse loss of the neural rim with a maximum remaining neural rim of <0.1, or nerve fiber layer defect in the arcuate bundles. Furthermore, two glaucoma specialists graded the VF loss as characteristic or compatible with glaucoma; caused by other nonglaucomatous/neurologic disease or artifact; or not determinable or not applicable based on the optic disc evaluation, clinical examination data, and evaluation of disc and fundus photographs. VF defects corresponding to the nerve fiber bundle pattern, which included nasal steps (either superior or inferior, but not both), paracentral defect, arcuate defect, and central island, temporal island, and absolute defect were defined as characteristic of glaucoma. VF defects that conformed to nerve fiber bundle loss but deviated in some manner from the characteristic defects, including altitudinal loss, both superior and inferior nasal steps, and defects with fair convergence, including a VF defect present in one VF but not in the second VF test (defects in the nasal, arcuate, or paracentral regions) were defined as compatible with glaucoma.