gms | German Medical Science

Background: The impact on intraocular pressure (IOP) of intraocular tamponades is of great importance for the development and the evaluation of new vitreous substitutes. We present a pseudo-in-vivo porcine model to monitor IOP continuously in the anterior chamber after vitrectomy.

Methods: The porcine eyes were obtained from a local abattoir and processed within 1 hour after death. The anterior chamber was perfused with DMEM, supplemented with 1.5 mg/mL glucose, 1% (vol/vol) fetal calf serum (FCS) and antibiotics (100 U/mL penicillin, 0.1 mg/mL streptomycin, and 17 g/mL gentamicin; all from Invitrogen, Karlsruhe, Germany) using a 27 gauge needle at a constant flow rate of 4.5 µL/min for 12 hours. 23G Pars Plana Vitrectomy (PPV) was performed on the intervention group and intraocular pressure development was compared to the control group. IOP was continuously monitored using 142PC01G pressure sensors (Honeywell™ Sensing and Control Minnesota, USA). Data was secured by the Datalogger AD 128™ (Valitec™, Value in Technology Inc, Ohio, USA) and processed using the software DataReady™ (Data Ready Technologies™, Florida, USA). Specimens of 5 eye pairs were fixed in 4% PFA for immunohistochemical investigations (TUNEL-stain).

Results: Mean IOP after 12 hours was 13 mm Hg in the control group in comparison to 14 mm Hg in the vitrectomized group. The difference in IOP after 12 hours between intervention and control was not significant P value>0.05. After 12 h TUNEL-stain showed 8.67% of dead cells in the region of the trabecular meshwork of vitrectomized eyes compared to 13.67% of cell death in the control group (p>0.05).

Conclusion: Our model seems suitable for continuous IOP monitoring after vitrectomy. This will become very useful for the preclinical testing of new vitreous substitutes.