Optic nerve head morphologic characteristics in high-tension and normal- tension glaucoma

Abstract

Objectives: To determine the morphometric parameters in high-tension glaucoma (HTG) and normal-tension glaucoma (NTG) with a confocal scanning laser ophthalmoscope, and to determine the relationship to disc size. Methods: One hundred eighty-six patients with glaucoma were recruited for this study. For each patient, only one eye was randomly chosen. Patients with NTG and HTG were classified using untreated intraocular pressure (lOP) as the variable; the NTG group had IOP less than 22 mm Hg during a diurnal tension curve, while patients with HTG had IOP greater than 21 mm Hg in at least 3 measurements. All the patients were examined with Humphrey perimeter program 30-2 and a Heidelberg Retina Tomograph. Findings were assessed by t test. Patients were then divided by disc area size into 3 subgroups: small discs with an area less than 2 mm2, midsized discs with an area of 2 to 3 mm2, and large discs with an area greater than 3 mm2. Results: One hundred thirty-two HTG eyes and 50 NTG eyes were assessed. Four eyes were excluded because they were classified as having secondary glaucoma. No significant differences were found between HTG and NTG eyes for any Heidelberg Retina Tomograph morphometric parameters, even when patients were divided into subgroups. Conclusion: No differences were apparent between HTG and NTG in morphometric parameters as measured by scanning laser ophthalmoscopy.