Abstract
Purpose :
Cataract surgery is the most frequent surgical procedure worldwide. Meta-analyses have shown that intraocular pressure (IOP) is significantly lowered after cataract surgery. Moreover, IOP can remain lower than pre-clinical values for up to 3 years. One of the hypotheses to explain this phenomenon is remodeling of the angle and the trabecular meshwork (TM) following surgery. The aim of the present study is to test this hypothesis by comparing the biometry of the TM and ciliary processes in pseudophakic (PS) versus phakic (P) donor eyes using advanced image analysis.
Methods :
Thirty-five formalin fixed pseudophakic and 25 phakic eyes with pertinent clinical history obtained from the Eyebank of Canada were sectioned to obtain a Miyake-Apple view. Next, a transverse section through the center of the pupil was made and the eye was embedded in paraffin, sectioned, stained with Masson’s trichrome stain, and converted into a digital slide (Aperio AT scanner). Using an image analyzer, the total TM area and the stroma of the ciliary body above the muscular bundles were demarcated. Supported by advanced automated image processing analysis, the area of the TM (ATM), cellular (CC) and non-cellular (NCC) TM compartments, trabecular space (TS), and degree of fibrosis of the ciliary processes (F) were evaluated.
Results :
The ATM was larger in the PS compared to the P group (P=0.02). Furthermore, a trend of larger TS in PS compared to P eyes was seen (P=0.14). No differences in the proportion of cellular (P=0.87) and non-cellular TM compartments (P=0.4) were noted between groups. In the ciliary process, a higher F was measured in the PS compared to the P group (P=0.02). The F score correlated poorly with the ATM (r2=-0.36, P=0.03).
Conclusions :
We conclusively demonstrated that there were significant changes in the trabecular meshwork post-cataract surgery. More specifically, the trabecular meshwork area was larger in pseudophakic eyes, which supports the hypothesis that TM remodeling is involved in lowering IOP following cataract surgery. Future studies are needed to determine the long-term trabecular meshwork changes following IOL insertion.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.