Optical coherence tomography parameters predictive of visual outcome after anti-VEGF therapy for retinal vein occlusion

Abstract

Purpose: To determine the optical coherence tomography (OCT) parameters that are predictive of visual outcome after anti-VEGF therapy for a retinal vein occlusion (RVO).

Methods: Fifty-seven eyes with macular edema (ME) secondary to a central or branch RVO treated with bevacizumab or ranibizumab were studied. Spectral-domain OCT and microperimetry were performed before, 1, 3, and 6 months after the treatment and at the final visit. Central retinal thickness (CRT), macular volume (MV), integrity of the external limiting membrane (ELM), ellipsoid zone (EZ), and foveal bulge (FB), and photoreceptor outer segment (PROS) length were determined.

Results: The mean follow-up period was 17.8±11.5 months. In 46 of the 57 eyes, a resolution of the ME was achieved. The pretreatment CRT and MV, presence of intact ELM, EZ, and FB, and PROS length at the time of ME resolution were significantly correlated with the best-corrected visual acuity and retinal sensitivity at the final visit (P<0.050). Multiple regression analyses showed that the pretreatment MV had the highest correlation with the posttreatment best-corrected visual acuity and retinal sensitivity (P<0.050).

Conclusion: The CRT, MV, ELM, EZ, FB, and PROS length are predictive factors for the visual outcome after anti-VEGF therapy for RVO.

Keywords: anti-VEGF therapy; retinal sensitivity; retinal vein occlusion; spectral-domain optical coherence tomography; visual acuity.

Figure 1

Microperimetry map and spectral-domain optical coherence tomography (SD-OCT) images of an eye with a branch retinal vein occlusion (71-year-old woman). Notes: (A) Microperimetry map before treatment. A total of 24 stimulus locations covering the central 10-degree field were tested. The mean retinal sensitivity at the 24 locations is 13.3 dB. The decimal best-corrected visual acuity was 0.8. (B) Retinal thickness map obtained by SD-OCT before treatment. The diameters of the center, inner, and outer rings were 1, 3, and 6 mm, respectively. The central retinal thickness was defined as the average thickness of the central 1 mm circle of the retinal thickness map. The macular volume (MV) was defined as the total MV of the central 3 mm circle, because the central 10-degree spot examined by microperimetry is comparable to a circle of approximately 3 mm in diameter in the fundus of an emmetropic eye. (C) SD-OCT image at the time of the resolution of macular edema after treatment. The external limiting membrane (ELM) and ellipsoid zone (EZ) are considered to be intact, because both are continuous and accompanied with signal intensity similar to that in the peripheral macula. SD-OCT image shows that the EZ line has a bulge at the central fovea, named the foveal bulge (arrowhead). Photoreceptor outer segment (PROS) length was measured as the distance between the EZ and the inner border of the retinal pigment epithelium (RPE) at the foveal center. Abbreviations: SD-OCT, spectral-domain optical coherence tomography; MV, macular volume; ELM, external limiting membrane; EZ, ellipsoid zone; PROS, photoreceptor outer segment; RPE, retinal pigment epithelium.

Figure 2

Correlation between the macular volume before treatment and the final visual acuity. Notes: The pretreatment macular volume is significantly correlated with the final visual acuity (r=0.455, P<0.001). The solid line represents the linear regression line (y=0.239x −0.636). Abbreviation: logMAR, logarithm of the minimum angle of resolution.

Figure 3

Correlation between the macular volume before treatment and the final retinal sensitivity. Notes: The pretreatment macular volume is significantly correlated with the final mean retinal sensitivity within the central 10 degrees (r=−0.438, P<0.001). The solid line represents the linear regression line; y=−2.688x +22.089.