Abstract
Purpose: :
To qualitatively evaluate macular anatomy in patients with exudative age-related macular degeneration (AMD) using ultrahigh resolution spectral domain optical coherence tomography (UHR-SDOCT), before and one month after intravitreal injection of ranibizumab.
Methods: :
A prototype UHR-SDOCT instrument capable of 3 to 3.5 micron axial resolution and ~25,000 lines/second was employed. 10 patients with exudative AMD were imaged with this prototype before and one month following intravitreal ranibizumab (IVR) injection. Fluorescein angiography and OCT3 was used for diagnosis of neovascularization in all patients.
Results: :
Before treatment, all patients demonstrated a thickened and irregular RPE layer. Bruch’s membrane was visible in 9/10 patients. Each patient manifested some degree of normalization of the retinal contour after IVR. In all patients with intraretinal, subretinal, or sub-RPE fluid, there was a reduction in the amount of fluid after treatment. Classic neovascular membranes appeared as highly-reflective lesions anterior to the RPE. Occult membranes were seen as moderately-reflective areas between the RPE and Bruch’s membrane. Both types of neovascular lesions did not change morphology significantly after treatment. A reflection from the outer segments was clearly visualized in 4/10 patients prior to IVR; this number did not increase after treatment. 8/10 patients had focal areas of thinning of the outer nuclear layer, which remained after treatment.
Conclusions: :
UHR-SDOCT is capable of unprecedented imaging speed and resolution, making it a valuable instrument in measuring in vivo intraretinal pathology. All treated patients had some normalization of retinal contour one month after a single treatment, likely secondary to a decrease in the amount of intraretinal, subretinal, and sub-RPE fluid. However, choroidal neovascular lesions did not change shape significantly, suggesting that ranibizumab may decrease permeability rather than cause regression of choroidal neovascularization. Photoreceptor abnormalities remained in all patients where they were pre-existent, suggesting that while ranibizumab improves overall retinal anatomy, some photoreceptor damage may be irreversible.
Keywords: age-related macular degeneration • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)