Histopathological changes in the anterior segment with anterior and posterior chamber intraocular lens.

Objective: Patients have shown a lowering of intraocular pressure (IOP) after cataract surgery. Histopathology studies have reported trabecular meshwork (TM) changes in pseudophakic eyes with posterior chamber intraocular lens (PCIOL) and have eluded to the mechanisms for IOP decrease. Unlike PCIOLs, TM histopathology changes after implantation of an anterior chamber intraocular lens (ACIOL) have not been studied, to our knowledge. Therefore, this study aims to examine the histopathological changes in both the TM and corneal endothelium among donor eyes with ACIOL, PCIOL, and phakic eyes.

Methods: Forty fixed postmortem donor eyes were obtained, sectioned, and embedded. Slides were stained with Masson's trichrome and CD31 vascular endothelial antibody, and further digitalized. Customized Medical Parachute TMAN software quantified the cellular components, the trabecular extracellular matrix (ECM), ECM fibrosis, and trabecular area. Schlemm's canal and corneal endothelium were quantified across the ACIOL, PCIOL, and phakic groups.

Results: Cellular area component of the TM was lower in the ACIOLs and PCIOLs than in phakic eyes, but statistically significant only between PCIOL and phakic eyes (p = 0.0023). ECM area component, TM fibrosis score and TM lamellae area, ciliary process fibrosis, and CD31 expression in Schlemm's canal showed no differences (p = 0.40, 0.99, 0.10, 0.83, 0.45). Significantly lower corneal endothelial cells were seen in ACIOLs compared with both PCIOLs and phakic eyes (p = 0.0002).

Conclusions: ACIOLs and PCIOLs in our sample group showed that there is loss of cellular components in the TM compared with the phakic eyes, with PCIOLs displaying the least amount of TM cells statistically, in this cohort. The ACIOLs led to a greater loss of corneal endothelial cells than both PCIOLs and phakic eyes after cataract surgery. The endothelial cells in Schlemm's canal did not seem to be affected by the IOL placements. Therefore, this study illustrates that there are histopathological differences seen with the placements of ACIOLs in both TM and cornea.