Revista nº 814

Choroidal thickness analysis in keratoconus patients | López-Jiménez A, et al. 254 Actual Med. 2021; 106(814): 252- 259 Statistical analysis Statistical analysis was calculated using Statistical Package for the Social Sciences (Version 24.0, SPSS, Chicago IL, USA). Initially, a descriptive study of each of the included variables was performed. The t-student test for independent samples was used to compare the quantitative variables of choroidal thickness of both groups. Statistical significance was considered as p<0.05. For the correlation between variables, we initially used tests of normality between them. To check the association between two quantitative variables we used the Pearson’s test if the distribution was normal, or the Spearman’s test if it was not normalized. To check the association between a quantitative and a categorical variable, the analysis of variance ANOVA was required. Measurements of the thirteen locations are expressed in microns (μm), and are composed of the mean value plus/minus the standard deviation. The mean age in the KC group was 34.12 ± 12 years-old (y.o) (range; 12 to 63 y.o) and in the control group 39.6 ± 14.6 y.o (range; 19 to 80 y.o). No significant differences were found in age distribution (p=0.073) (Table 1). Female/male ratio represented 13/13 (50/50%) in the KC group and 18/8(69/31%) in the control group. These differences did not reach statistical significance (p=0.23). The mean BCVA was 0.69 ± 0.30 in the KC group and 0.99 ± 0.04 in the control group. BCVA was firstly measured with letter optotypes on a decimal scale and transformed later to the log MAR (minimal angle of resolution). Statistically significant differences were observed for BCVA between both groups (p < 0.001) (Table 1). RESULTS Table 2. Mean choroidal thickness measurements in both groups. Significant difference was only observed in T6. CT: choroidal thickness, K: keratoconus, p: values from independent t-test, N: nasal, M: subfoveal choroidal thickness, T: temporal. Table 1. KC: keratoconus, F: female, M: male, BCVA: best corrected visual acuity, MAR: minimum angle of resolution KC group Control group Age Mean Range 34,12 ± 12 (12 /63) 39,6 ± 14,6 (19/80) Sex 13 F / 13 M 17 F / 8M BCVA (means) Log MAR (mean) 0,69 ± 0,30 0.161 0,99 ± 0,04 0,004 N6 N5 N4 N3 N2 N1 KC group (means± SD μm) 183,64 ± 62,23μm 218,68 ± 69,43 μm 252,28 ± 87,02 μm 282,08 ± 91,97 μm 307,28 ± 90,25 μm 334,24 ± 102,99 μm Control group (means± SD μm) 175,96 ± 72,84 μm 240,35 ± 112,03 μm 263,83 ± 106,11 μm 296,39 ± 103,09 μm 331,74 ± 109,48 μm 346,13 ± 111,15 μm p p=0,695 p=0,421 p=0,681 p=0,614 p=0,401 p=0,702