Optical tomography-measured retinal nerve fiber layer thickness in normal latinos

To measure retinal nerve fiber layer (RNFL) thickness in normal Latinos using optical coherence tomography (OCT).

Three hundred twelve Latino participants, aged 40 years or more, underwent a detailed ophthalmic examination, including measurement of visual acuity, intraocular pressure, visual field perimetry, and stereoscopic optic disc photography. None of the participants had any evidence of ocular hypertension, glaucoma, or other ocular disease. Nine scans were performed on one eye of each participant by optical coherence tomography (OCT Model 2000; Carl Zeiss Meditec, Dublin, CA, software version A 6.1): three circumferential peripapillary scans and six radial scans of the macula. The average RNFL thicknesses in the peripapillary region and macula were measured. A paired t-test and linear regression analyses were used to analyze the data.

The mean age of the participants was 52 years (range, 40-79 years). The average peripapillary RNFL thickness 1.74 mm from the center of the disc was 132.7 +/- 14.4 micro m, and the average macular RNFL thickness was 44.8 +/- 14.8 micro m. The average macular retinal thickness was 173 +/- 28.5 micro m. The average peripapillary RNFL thickness in the four quadrants was as follows: superior 157.7 +/- 17.8 micro m, nasal 109.3 +/- 19.1 micro m, inferior 159.8 +/- 18.9 micro m, and temporal 102.5 +/- 19.0 micro m. There were no gender-related differences in macular or peripapillary RNFL thickness (P = 0.12 and P = 0.35, respectively). The average macular and peripapillary RNFL thickness was thinner in older Latinos than in younger Latinos (P = 0.04 and P = 0.0001, respectively).

Regional and age-related differences in the peripapillary and macular RNFL thickness should be considered when diagnosing and monitoring individuals with diseases that affect the RNFL.