Observation of optic disc neovascularization using OCT angiography in proliferative diabetic retinopathy after intravitreal conbercept injections

Abstract

This study reports the short-term efficacy and safety of intravitreal conbercept injections for neovascularization at the disc (NVD) in patients with proliferative diabetic retinopathy (PDR). Conbercept is a recombinant fusion protein with a high affinity for all isoforms of vascular endothelial growth factor (VEGF)-A, placental growth factor and VEGF-B. A prospective case series study was conducted in 15 patients (15 eyes). Patients had complete ocular examinations and received a 0.5 mg intravitreal conbercept injection followed by supplemental pan-retinal photocoagulation (PRP). Optical coherence tomography angiography (OCTA) was performed before and after treatment. Before treatment, the mean NVD area was 1.05 ± 0.33 mm², and it decreased to 0.56 ± 0.17 mm² after an interval of 7.5 d (p = 0.000). One eye required vitrectomy during follow-up. Recurrent NVD was observed in 2 eyes, which resolved after repeated injections. The remaining 12 eyes were stable over a mean follow-up period of 8.3 months. The mean area of the NVD in 14 patients without vitrectomy was 0.22 ± 0.11 mm² (p = 0.000) at the last visit. Intravitreal conbercept injections combined with intensive PRP are an effective and safe treatment for PDR with NVD. Quantitative information on NVD can be obtained with OCTA, which may be clinically useful in evaluating the therapeutic effect.

Figure 1

The procedure to measure the neovascularization at the disc (NVD). (A) A circle with a 3-mm diameter was drawn that was centered at the optic disc; (B) The structure of the NVD was outlined with white lines, and the background was colored black.

Figure 2

Male, 50 years old, NVD of the left eye. (A) OCTA showed obvious NVD before treatment; (B) The processed image, where the area of the NVD was 1.27 mm². (C) OCTA showed a significant decrease of the NVD 7 days after intravitreal conbercept therapy; (D) The processed image, where the area of the NVD was 0.65 mm².

Figure 3

Female, 62 years old, NVD of the right eye. (A) Before treatment, OCTA showed obvious NVD and exuberant vascular proliferation (EVPs) in the upper margin; (B) The processed image, where the area of the NVD was 1.13 mm². (C) One week after intravitreal conbercept therapy, OCTA showed an alleviation of the NVD and the disappearance of EVPs; (D) The processed image, where the area of the NVD was 0.71 mm². (E) OCTA image of the NVD one month after intravitreal conbercept therapy and laser treatment; (F) The processed image, where the area of the NVD was 0.39 mm². (G) OCTA image of the NVD 14 months after intravitreal conbercept therapy and laser treatment; (H) The processed image, where the area of the NVD was 0.24 mm².

Figure 4

Male, 37 years old, NVD of the left eye. (A) Before treatment, OCTA showed obvious NVD and EVPs; (B) The processed image, where the area of the NVD was 0.97 mm². (C) Nine days after intravitreal conbercept therapy, OCTA showed an alleviation of the NVD and the disappearance of EVPs; (D) The processed image, where the area of the NVD was 0.25 mm². (E) OCTA showed NVD regrowth and EVPs reappearance 8 weeks after intravitreal conbercept therapy and laser treatment; (F) The processed image, where the area of the NVD was 1.01 mm². (G) The patient underwent vitrectomy surgery because of a vitreous hemorrhage and proliferative membrane formation. Four months after surgery, OCTA showed a normal structure of the optic nerve head without NVD; (H) B-scan OCT confirmed the absence of NVD.