Wistar rat model experiments for increasing intraocular pressure: a systematic review

Glaucoma is a leading cause of irreversible vision loss, with elevated intraocular pressure (IOP) being the primary modifiable risk factor. Experimental models that reliably induce ocular hypertension (OHT) are essential for understanding disease mechanisms and evaluating therapeutic interventions. Wistar rats are widely used due to their ocular anatomy and suitability for repeated IOP measurements.

This systematic review was conducted in accordance with PRISMA guidelines and included studies published from 2000 onwards. Multiple databases were searched to identify experimental studies inducing OHT in Wistar rats. Data on model type, peak IOP, duration of elevation, and measurement techniques were extracted. Methodological quality was assessed using the SYRCLE risk of bias tool.

A total of 27 studies were included. Considerable heterogeneity was observed in the onset, magnitude, and duration of IOP elevation across models. Corticosteroid models showed gradual IOP increase, typically peaking around 3-4 weeks. Intracameral injection models induced rapid IOP spikes, whereas microsphere-based approaches demonstrated more sustained elevation. Episcleral vein ligation and cauterization models resulted in immediate and prolonged IOP elevation, while laser photocoagulation produced moderate to high increases with sustained effects. The circumlimbal suture model exhibited a biphasic response, with an initial spike followed by prolonged elevation. Variability in IOP measurements was influenced by differences in tonometry and experimental protocols.

Wistar rat models of OHT exhibit diverse temporal and mechanistic profiles, with no single model fully replicating all aspects of glaucoma. This review uniquely provides a synthesis of peak IOP, time to peak, and duration of elevation across models, offering a practical framework for model selection.