Retinal nerve fiber layer height in high-tension glaucoma and healthy eyes

To determine the correlations between the retinal nerve fiber layer height measured by Heidelberg Retina Tomograph, version 1.11, and visual field indices in healthy individuals and patients with glaucoma.

One eye was randomly chosen from 48 patients with glaucoma and 60 healthy individuals. All participants were classified using Humprey visual field, program 30-2 (Humphrey Instruments, Inc., San Leandro, CA, U.S.A.); mean deviation, pattern standard deviation, short-term fluctuation, and corrected pattern standard deviation were measured. Superior and inferior mean deviation were calculated. For each participants the mean Heidelberg Retina Tomograph was generated from three 10 degrees Heidelberg Retina Tomograph pictures. The Student t test was used to compare healthy and glaucomatous retinal nerve fiber layer (RNFL) mean degree values every 5 degrees. A global measurement, superior sector (25 degrees-125 degrees), nasal sector (130 degrees-230 degrees), inferior sector (235 degrees-335 degrees), temporal sector (340 degrees-20 degrees), and polar sector (superior + inferior) were calculated. The global, superior, nasal, inferior, temporal, and polar RNFL height (RNFLH) were compared between healthy individuals and patients with glaucoma. The correlation between global, superior, inferior, and polar retinal nerve fiber layer height and visual field was calculated.

A significant difference was found for RNFLH mean from 45 degrees to 330 degrees and for the distribution of the means (as reflected by the standard deviation) from 85 degrees to 100 degrees, 260 degrees to 295 degrees, and 335 degrees to 5 degrees. From these data we created three new sectors: new superior sector (from 85 degrees to 100 degrees), new inferior sector (from 260 degrees to 295 degrees), and new polar sector (combining the new superior and the new inferior sector). Comparing the healthy individuals to the patients with glaucoma, the mean RNFLH values for each sector were found to differ significantly (p < 0.001), with the exception of the temporal sector. Significant correlations (p < 0.001) between the global RNFLH and mean deviation (r = -0.36), pattern standard deviation (r = 0.49), and corrected pattern standard deviation (r = 0.48) were found in healthy participants and those with glaucoma. The strongest correlations (p < 0.001) were found between the pattern standard deviation and the corrected pattern standard deviation with the new polar sector (r = 0.60 and r = 0.59, respectively).

We found that the strongest correlations with the visual field were with the new polar and new inferior sector.