Abstract
Purpose :
To evaluate preclinical safety of ophthalmic viscosurgical devices (OVDs) through an aqueous exchange model in rabbit and with the development of a novel in vivo mini-pig model.
Methods :
OVDs containing animal-sourced sodium hyaluronate (HA) (Healon & Healon5 brands) and bacterial-sourced HA (Healon PRO & Healon5 PRO brands) were used. To assess potential inflammation and intraocular pressure (IOP) changes in response to OVDs, aqueous humor was exchanged with OVDs in rabbit eyes in vivo. Slit-lamp exam, pachymetry and IOP measurements were performed until 7 days post procedure. To evaluate potential protective effects of OVDs on corneal endothelial cell during cataract surgery, mini-pigs were selected based on their limited capacity, as that in humans, to regenerate the corneal endothelium post injury. Healon PRO and Healon5 PRO OVDs were compared to Healon and Healon5 OVDs (controls), respectively. In each case, both eyes of six animals were subjected to OVD injection and intraocular lens (IOL) implantation. Slit-lamp examination, pachymetry, and IOP measurements were performed on day 1, 3, 7, and 14 days post-surgery.
Results :
Slit-lamp exams of rabbits undergone aqueous exchange procedures with OVD in each eye showed mild irritation related to the surgical procedure. All OVDs induced a postoperative increase in IOP that returned to the preoperative level at 24 hours. IOP and pachymetry measurements were not significantly different between animal or bacterial-sourced HA injected eyes (n=6, 0.07<p<1.0). Although it was deemed the most appropriate model for corneal endothelial cell investigations, the mini-pig model did pose technical challenges in regards to sedation and surgery induced inflammation. Changes in IOP were consistent with changes that occur during surgical procedures, while corneal thickness and endothelial cell density remained relatively constant. IOP (p>0.18), corneal thickness (p>0.19), and endothelial cell density (p>0.28) were similar throughout the study regardless of the source of HA in the OVDs.
Conclusions :
The aqueous exchange studies in rabbits, and IOL implantation studies in mini-pigs using OVDs with animal- or bacterial-derived HA, demonstrate equivalence of OVDs regardless of HA source. The mini-pig model was shown to be a useful tool for future studies comparing various OVDs with respect to protective propensity on corneal endothelial cells during cataract surgery.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.