Background: Intravitreal injection of anti-vascular endothelial growth factor agents is the most common intraocular procedure worldwide, inevitably causing more cases of post-injection endophthalmitis. The purpose of this study was to evaluate the utility of laser flare photometry in monitoring inflammation after intravitreal injection of anti-vascular endothelial growth factor agents, particularly to detect early stage post-injection endophthalmitis. A retrospective case review was performed of all patients who underwent flare assessment by laser flare photometry before and after intravitreal injection of bevacizumab or aflibercept at the Centre for Ophthalmic Specialized Care in Lausanne, Switzerland, between January 2015 and May 2018. The following data were retrieved: indication for intravitreal injection, medication administered, pre-injection and 72-h post-injection laser flare photometry values, and occurrence of post-injection endophthalmitis. A total of 736 injections were included in this study; 705 cases (95.8%) had a post-injection flare at 72 h ≤ 30 ph/ms, 29 cases (3.9%) had a post-injection flare at 72 h between > 30 and 50 ph/ms, and 2 cases (0.3%) had a post-injection flare at 72 h above > 50 ph/ms (664 and 742 ph/ms). These latter two cases were diagnosed as early-stage endophthalmitis.
Conclusion: Laser flare photometry is a cost-effective method of screening for early stage post-injection endophthalmitis. Values > 50 ph/ms 72-h post-injection should prompt immediate evaluation by an ophthalmologist.
Keywords: Endophthalmitis; Intravitreal injection; Laser flare photometry.