Demographic Characteristics of study participants
The results of the study showed that 47.7% of the participants were males (n = 21) while 52.3% were females (n = 23). The mean age of the participants was 51.1 years, with a standard deviation of ± 22.5 (range; 18 to 91 years). The mean age for males was 58.4 ± 21.3 and for females was 44.4 ± 22.0. An independent t-test depicted that the mean difference in age between sex was statistically significant t (86) = 3.0327, p = 0.0032. According to age, the majority of the participants belonged to the 18–39 years’ age group (n = 16), 36.1% and the minority age group was ≥ 80 years. (Table 1).
Table 1
Demographic characteristics of the study participants
Age groups | Males | Females |
All participants | 21 (47.7%) | 23 (52.3%) |
18–39 years | 6 (13.4%) | 10 (22.7%) |
40–59 years | 3 (6.8%) | 7 (15.9%) |
60–79 years | 9 (20.5%) | 5 (11.4%) |
≥ 80 years | 3 (6.8%) | 1 (2.2%) |
| Mean (SD) | Range |
Age | 51.1 ± 22.5 | 18–91 |
| Mean IOP (nfGAT) | Mean IOP (fGAT) |
Glaucoma | 17.55 ± 5.64 | 18.25 ± 5.80 |
Non-glaucoma | 13.34 ± 1.48 | 13.60 ± 1.22 |
Relationship between IOP with and without fluorescein among glaucomatous subjects |
According to sex, the glaucoma group had 12 (54.5) males and 10 (45.5%) females while the non-glaucoma group had 9(40.9%) males and 13(59.1%) females, however, a Chi-square test showed that there is no statistically significant association between sex and glaucoma (p = 0.365). Regarding age group, the majority 10 (45.5%) of glaucoma participants were between the age group 60–79 years and the least frequent age group was 18–39 years 2 (9.1%) while in the non-glaucoma group, the most common age group was 18–39 years 14 (63.6%) and the least frequent was 80 years and above 1 (4.5%). Pearson's Chi-Square test showed that there is a statistically significant association between having glaucoma and age (p = 0.003).
Distribution of GAT values
In general, the average mean IOP without fluorescein was lower 15.44 (SD = 4.598) mmHg compared to GAT with fluorescein at 15.92 (SD = 4.76) mmHg. A paired t-test indicated that the difference was statistically significant (p < 0.001). According to the study group, the mean IOP reading among glaucomatous subjects was 17.55 ± 5.64 mmHG with non-Fluorescein GAT (nfGAT) and 18.25 ± 5.80 mmHg with Fluorescein GAT (fGAT). Paired t-test showed that the difference was statistically significant (p = 0.001). On the other hand, the mean IOP among non-glaucomatous subjects was 13.34 ± 1.48 mmHg with nfGAT and 13.60 ± 1.22 mmHg with fGAT. The paired t-test showed a statistically significant difference between the two means (p = 0.020).
Relationship between fGAT and nGAT
A Pearson correlation coefficient test depicted a statistically significant strong positive correlation in IOP measurement between the Glaucomatous group (R = 0.989, R2 = 0.977, p < 0.001) and the non-glaucomatous group (R = 0.955, R2 = 0.913, p < 0.001) (Figs. 1 and 2)
Relationship between nfGAT and fGAT according to sex
Among male glaucomatous subjects, mean IOP was 18.20 ± 7.17 mmHg with nfGAT and 18.82 ± 7.16 mmHg with fGAT. Wilcoxon test showed statistically significant difference between the two mean IOPs (p = 0.017), with mean fGAT IOP being high. In female glaucomatous subjects, mean IOP of 16.78 ± 3.18 mmHg for nfGAT and 17.57 ± 3.87 mmHg for fGAT. Results showed a significant difference between nfGAT and fGAT IOP (p = 0.032), with fGAT mean IOP being higher than nfGAT. (Fig. 3)
Among non-glaucomatous male subjects, mean IOP was 13.63 ± 1.48 mmHg with nfGAT and 13.81 ± 1.23 mmHg with fGAT. Wilcoxon test showed that there was no significant difference between the two IOP measurements (p = 0.172). However, among non-glaucomatous female subjects there was significant difference between nfGAT mean IOP which was 13.14 ± 1.48 mmHg, and fGAT mean IOP which was 13.45 ± 1.23 mmHg (p = 0.049). The Wilcoxon test results among glaucomatous subjects showed statistically significance difference between nfGAT and fGAT (P = 0.049). (Table 2)
Table 2
Wilcoxon matched-paired test for mean IOP between nfGAT and fGAT in non-glaucomatous subjects based on sex
Sex | Mean IOP nfGAT | Mean IOP fGAT | P-value |
Males | 13.63 ± 1.48 | 13.81 ± 1.23 | 0.172 |
Female | 13.14 ± 1.48 | 13.45 ± 1.23 | 0.049* |
Relationship between nfGAT and fGAT according to age among glaucomatous |
Relationship between nfGAT and fGAT according to age
Among glaucomatous subjects, Wilcoxon matched-pair tests significant difference between the two tests were only observed in age group 60–79 years (p = 0.04). (Fig. 4). Among non-glaucomatous subjects, none of the age groups showed a significant difference between nfGAT and fGAT IOP (all p > 0.05). (Fig. 5)