Acute Diffuse Retinal Hemorrhage Following Intravitreal Conbercept Injection: A Case Report and Mechanistic Analysis

Summary

This case report describes a rare adverse event of acute diffuse retinal hemorrhage in a patient with multiple comorbidities following a series of anti-VEGF treatments. The report explores this adverse event's possible mechanisms, clinical presentation, management, and outcomes.

Abstract

Acute diffuse retinal hemorrhage is a rare but potentially serious complication following intravitreal anti-vascular endothelial growth factor (anti-vascular endothelial growth factor [VEGF]) therapy. Conbercept, a recombinant fusion protein, has been widely used for treating various retinal vascular disorders and has demonstrated both clinical efficacy and safety. Despite its widespread use, isolated reports of acute retinal hemorrhage post-injection have raised concerns. The case report presented here describes an episode of acute diffuse retinal hemorrhage occurring 24 h after the 12^th intravitreal conbercept (IVC) injection in a patient. The patient's significant risk factors included a long-standing history of poorly controlled diabetes mellitus, chronic hypertension, and advanced proliferative diabetic retinopathy (PDR). The patient had undergone pan-retinal photocoagulation in both eyes and received 11 bilateral IVC injections (0.5 mg/0.05 mL per eye) over a 12-month period. This report examines the underlying mechanisms, clinical course, and management, emphasizing the importance of personalized strategies for complex cases.

Introduction

This case report details an episode of acute diffuse retinal hemorrhage occurring 24 h after the 12th intravitreal conbercept (IVC) injection in a patient with refractory PDR. While anti-VEGF agents are a cornerstone in managing PDR, understanding the context of rare hemorrhagic adverse events is critical for risk assessment and patient care^1,2. A review of existing literature establishes that while minor, injection-site hemorrhages are common across all anti-VEGF agents, severe intraocular hemorrhages are infrequent. For widely used agents like ranibizumab and aflibercept, post-injection vitreous hemorrhage i....

Protocol

​This study adhered to established medical ethics and was conducted under a standard clinical protocol approved by the Ethics Committee of Chongqing University Three Gorges Hospital (Approval No. 2025046). Written informed consent was obtained from the patient prior to participation.

1. Pre-surgical steps

1. Preoperatively, the patient presented with an elevated intraocular pressure of 36.3 mmHg in the right eye. This was successfully reduced to 19.2 mmHg following the administration of topical (timolol-dorzolamide) and systemic (oral acetazolamide) hypotensive agents.
2. At the time of the injection, the patient's....

Results

At 1 month follow-up, the patient reported a subjective improvement in vision. This was consistent with objective findings, as the best-corrected visual acuity (BCVA) had improved to 20/40. The fundus examination revealed a partial resolution of the hemorrhagic lesions and reduced macular edema (Figure 3A). Correspondingly, optical coherence tomography (OCT) demonstrated improved macular architecture, with the central subfield thickness having decreased to 452 µm (F.......

Discussion

Acute diffuse retinal hemorrhage following intravitreal conbercept injection is a rare but potentially sight-threatening complication, often observed in eyes with advanced proliferative diabetic retinopathy (PDR) and systemic comorbidities^5,6,7,8,9. The pathogenesis of this diffuse retinal hemorrhage is likely multifactorial, stemming from the potent pharmacod.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Brinzolamide eye drops	Alcon-Couvreur	HJ20140976
Carbazochrome SodiumSulfonate for Injection	Jiangsu Wuzhong Group	H20044326
Conbercept Ophthalmic Injection	Chengdu Kanghong Pharmaceutical Group	202204b11
Fundus camera	CarlZeiss Meditec,Inc	CLARAS 500
Hexue Mingmu Pian	Xi'an Beilin Pharmaceutical Co., Ltd	Z20025067
Non-contact tonometer	TOPCON	CT-800A
Optical Coherence Tomography	Heidelberg Engineering	SpectraLisOCT
Refractometer	TOPCON	KR-800