Abstract
Purpose: :
To compare in vivo corneal thickness and endothelial cell changes during the acute post-operative period after phacoemulsification.
Methods: :
In this retrospective study, thirty (30) patients underwent phacoemulsification and their endothelial cell size (ECS), endothelial cell count (ECC) and corneal thickness (CT) were measured before surgery and at different times briefly after surgery: Post-operative day (POD) 1-3 (group 1), POD 4-6 (group 2), and POD 7-9 (group 3). The same Topcon specular microscope was used on all patients by the same operator. Statistical analysis was performed by using a paired t-test and one-way ANOVA to compare groups.
Results: :
Mean ECC was 2721, 2413 and 2417 in groups 1, 2, and 3 respectively pre-operatively; and 2429, 2131, and 2211 post-operatively. Mean ECC change was 292, 282, and 206 for each group. ECC was significantly lower for all groups (P=0.004, P=0.0075, P=0.004).Mean pre-operative ECS was 368 microns, 417, and 414 and post-operative ECS was 415, 440 and 429 in each group respectively. ECS was significantly higher for group 1. Mean pre-operative CT was 0.491 mm, 0.470, and 0.487 for each group. Mean post-operative CT was 0.535 mm, 0.499, 0.486. The CT was significantly higher for group 2 (P=0.002). One-way ANOVA demonstrated that the three groups were not statistically different from each other (p=0.37) when average phaco power used for the surgery was controlled.
Conclusions: :
Our study showed significantly lower endothelial cell counts in all three groups post-operatively, but interestingly, only showed significant changes in ECS in group 1 and a significant change in CT in group 2. These results may indicate that in the face of an acute insult leading to decreased ECC, the endothelium undergoes structural modification (in this case cell size). The normal physiologic pumping activity of the endothelium may be disrupted, taking several days to recover leading to corneal edema. This may be the reason why the corneal thickness is significantly higher in group 2. It is unclear, however, if these changes are due to the mechanical forces of phacoemulsification or physiologic response to an acute insult. In clinical practice it is also important to properly manage IOP post-operatively, which is directly related to corneal thickness. Having more insight into the natural course of the acute corneal response and healing post-operatively may lead to improved post-operative management. As our sample size in this project was relatively small, we hope to use this pilot study to warrant further analysis of corneal morphology pre- and post-phacoemulsification surgery.
Keywords: cornea: endothelium • cornea: clinical science