Purpose:
To compare CSLO measures between ethnic groups in the normal databases of the HRT 3.
Methods:
CSLO variables of healthy eyes were compared between three ethnic groups (Caucasians, African Americans, and Indians). All participants underwent a full eye examination, standard achromatic perimetry (SITA– standard 24–2) and confocal scanning laser ophthalmoscopy (Heidelberg Retinal Tomograph HRT I or II). All participants had normal visual fields (GHT within normal limits and PSD > 5%) and IOP <22 mm Hg. Analysis of Variance (ANOVA) was performed on the stereometric parameters and post–hoc t–tests were performed on the significant variables using Tukey–Kramer HSD. Correlations were also calculated between the parameters and patient age and disc size in all groups.
Results:
Descriptive statistics for the stereometric parameters (mean +/– standard deviation) are shown in the table. The ANOVA showed significant differences for all parameters between ethnic groups (p < .005 in all tests). Post–hoc t–tests revealed many significant differences between specific groups for all variables. Strong correlations were found for disc size and cup and rim area for all groups (average R–square across groups = 0.40 and 0.48 respectively), with weaker correlations for linear C/D and mean RNFL thickness (average R–square across groups = 0.14 and 0.01 respectively). Correlations between age and parameters were very weak, with average R–square values less than 0.01 for all parameters. However, large differences were present in the strength of the correlations between the different groups for all parameters.
Conclusions:
There are differences between ethnic groups in many CSLO parameters, both in their absolute values and in their correlation with disc size and age. These differences suggest ethnic specific databases are important for accurate clinical evaluations with CSLO imaging.
Keywords: imaging/image analysis: clinical • optic disc • nerve fiber layer