Optic nerve heads in pediatric African Americans using retinal tomography.

Objective: To characterize optic nerve head (ONH) parameters including symmetry between the eyes in healthy African American children using the Heidelberg retinal tomograph II, and to determine if there are associations between these parameters and age, refractive error, or gender.

Methods: The ONHs of 146 African American children aged 6 to 17 years without ocular disease were imaged with the Heidelberg retinal tomograph II. Mean values for 11 ONH parameters were determined as was their relationship to age, gender, and refractive error. Interocular symmetry of the parameters was determined.

Results: The mean (+/-standard deviation) disc area, rim area, and cup area were 2.18 +/- 0.57 mm2, 1.63 +/- 0.40 mm2, and 0.52 +/- 0.37 mm2, respectively. The mean linear cup-to-disc (C/D) ratio was 0.45 +/- 0.15, and mean cup depth was 0.22 +/- 0.10 mm. The mean retinal nerve fiber layer thickness was 0.26 +/- 0.07 mm. The ONH parameters were not related to age or refractive error. With the exception of the C/D area ratio and linear C/D ratio, which were greater in boys than in girls, ONH parameters were not related to gender. Most parameters were strongly correlated between the right and left eyes. The average interocular differences in disc area, cup area, rim area, linear C/D ratio, and mean retinal nerve fiber layer thickness were 0.09 +/- 0.31 mm2, 0.04 +/- 0.22 mm2, 0.06 +/- 0.40 mm2, 0.02 +/- 0.11, and 0.00 +/- 0.06 mm2, respectively.

Conclusions: ONH parameters were not related to age and refractive error, and only C/D area ratio and linear C/D ratio were greater in boys than girls in a clinical sample of African American children. These measures of normative ONH parameters and range of interocular differences may be helpful in clinical pediatric eye care to facilitate identification of African American children with abnormal optic discs.