Influence of repetitive intravitreal ranibizumab for neovascular age-related macular degeneration on retinal pigment epithelium and choroidal thickness

Background

Intravitreal injection of ranibizumab (IVR) is one of the most effective therapies for neovascular age-related macular degeneration (nAMD). Understanding the influence of IVR on retinal pigment epithelium (RPE) and choroidal thickness is helpful for us to choose the operative times and timing based on pharmacologic effects and tissue response.However, limited studies are available about quantitative analysis of RPE atrophic area and subfoveal choroidal thickness after IVR for nAMD.

Objective

This study was to report the changes of RPE atrophic area and subfoveal choroidal thickness after IVR for nAMD.

Methods

A prospective series cases-observational study was designed.Forty-one eyes of 41 consecutive patients with nAMD were enrolled in Renmin Hospital of Wuhan University from January 2015 to June 2015, and written informed consent was obtained from each patient prior to entering the cohort.The affected eyes received intravitreal injection of 0.05 ml ranibizumab (10 mg/ml) and then followed up monthly for 12 months.The RPE atrophy area around macula and subfoveal choroidal thickness were measured by a newly developed RPE analysis software spectral-domain optical coherence tomography (OCT) and enhanced depth imaging of SD-OCT (EDI-OCT), respectively, and the RPE atrophy area and choroidal thickness changes were compared before IVR and 3, 6 and 12 months after IVR.The correlation between RPE atrophy area and choroidal thickness before and after IVR was analyzed.

Results

All the patients finished the treating procedure and follow up.The visual acuity (logMAR) after IVR was considerably improved in comparison with before IVR (F=7.631, P<0.001). The mean subfoveal choroidal thickness value was (264.55±100.95) μm before IVR, and that of 3, 6, 12 months after IVR was (247.42±105.46), (246.81± 99.85) and (253.97±101.15)μm, respectively, showing a significant difference among different time points (F=2.030, P<0.05), and the mean subfoveal choroidal thickness values 3, 6, 12 months after IVR were evidently thinned in comparison with before IVR (all at P<0.05). No significant difference was found in RPE atrophic area among different time points (F=0.116, P=0.951). Weak linear correlations were seen between RPE atrophy area and choroidal thickness (r=-0.185), the RPE atrophy area change values and choroidal thickness change values between IVR >6 times and ≤6 times (r=0.297, -0.327), but these results were not statistically significant (P=0.248, 0.282, 0.103). At the end of the follow up, weak linear correlations were seen in RPE atrophy area change values and choroidal thickness change values with IVR times (r_s=-0.266, 0.342), but these results were not statistically significant (P=0.148, 0.060).

Conclusions

IVR for nAMD can lead to subfoveal choroid atrophy instead of RPE atrophy.IVR does not accelerate the atrophy progression of both RPE and choroid.

Antibodies, monoclonal, humanized/therapeutic use; Ranibizumab; Wet age-related macular degeneration/drug therapy; Choroidal neovascularization/drug therapy; Intravitreal injection; Pigment epithelium of eye; Choroidal thickness/drug effects; Tomography, optical coherence