Ocular rigidity in patients with age-related macular degeneration.

PURPOSE To compare the ocular rigidity in vivo measurements of patients with age-related macular degeneration (AMD) and control subjects. DESIGN Prospective comparative clinical study. METHODS The pressure-volume relation and the ocular rigidity coefficient were compared among 32 patients with AMD (AMD group: 16 with neovascular and 16 with nonneovascular AMD) and 44 age-matched control patients (control group) who underwent operation for cataract. This was achieved by an injection of 200 microl of a balanced salt solution (in steps of 4.5 microl) through the limbus in the anterior chamber, while the intraocular pressure was monitored continually with a transducer, up to the limit of 30 mm Hg. RESULTS The mean age (AMD group: 69.89 +/- 15.92 years vs control group: 65.28 +/- 12.34 years; P = .195), gender (AMD group: 13 female vs control group: 17 female; P = .513), eye's axial length (AMD group: 23.14 +/- 0.75 mm vs control group: 23.04 +/- 1.16 mm; P = .725) of patients with AMD and the healthy control subjects were comparable. No statistically significant difference in ocular rigidity measurements between patients with AMD and control subjects (AMD group: 0.0142 +/- 0.0077 microl(-1) vs control group: 0.0125 +/- 0.0049 microl(-1); P = .255) was found. When we examined separately the two subgroups of patients with AMD (neovascular and nonneovascular AMD), the average ocular rigidity measurements were higher in patients with neovascular AMD vs both control subjects and patients with nonneovascular AMD (neovascular AMD group: 0.0186 +/- 0.0078 microl(-1) vs control group: 0.0125 +/- 0.0048 microl(-1) [P = .014] vs nonneovascular AMD group: 0.0104 +/- 0.0053 microl(-1) [P = .004]). CONCLUSIONS Despite the limitations placed by the small sample of the examined cases, patients with neovascular AMD who are treated (with photodynamic therapy) have increased ocular rigidity measurements compared with patients with nonneovascular AMD and control patients.