Figure 3 depicts the modified Early Treatment Diabetic Retinopathy Study (ETDRS) grid used for the comparisons of CC FD% measurements.
Table 3 shows comparisons of CC FD% measurements before and after cataract surgery within different regions. In the central 1-mm circle, the mean CC FD% decreased from 15.17% before surgery to 12.87% after surgery (
P < 0.001). The difference was 2.31%, with a 95% CI between 0.99% and 3.62%. In the 3-mm circle, the mean CC FD% decreased significantly from 12.03% to 11.36% after cataract removal (
P = 0.011; mean difference, 0.67%; 95% CI, 0.15–1.20). However, in the 5-mm circle, the difference in CC FD% measurements before and after surgery was not statistically significant (
P = 0.509; mean difference, 0.11%; 95% CI, −0.22 to 0.45). In the 17 cases with better image quality after surgery, the mean CC FD% decreased from 14.70% to 11.82% in the 1-mm circle, from 12.25% to 11.17% in the 3-mm circle, and from 9.78% to 9.25% in the 5-mm circle. In the seven cases with worse image quality after surgery, the mean CC FD% increased from 15.08% to 16.09% in the 1-mm circle, from 11.18% to 11.48% in the 3-mm circle, and from 8.97% to 9.66% in the 5-mm circle. In the case shown in
Figure 1 with better image quality after surgery, the CC FD% measurements decreased from 20.12%, 12.27%, and 9.50% in the central 1-mm, 3-mm, and 5-mm circles to 16.62%, 11.66%, and 8.95%, respectively. In the case shown in
Figure 2 with worse image quality after surgery, there were increases in CC FD% measurements from 9.99%, 12.76%, and 10.33% to 10.28%, 13.78%, and 11.26% in the 1-mm, 3-mm, and 5-mm circles, respectively.
Table 3 also shows all of the CC FD% measurements from all of the grid regions, and there were no significant changes in CC FD% measurements in any of the inner and outer quadrants. Not surprisingly, we found statistically significant negative correlations when we correlated the change in image quality with the change in the CC FD% within the 1-mm circle (
P = 0.004), 3-mm circle (
P < 0.001), and the 5-mm circle (
P < 0.001).