In vivo 3D Imaging of Age Related Macular Degeneration Using Optical Coherence Tomography at 1050 Nm

Abstract

 

Purpose:

 

To assess the application of ophthalmic optical frequency domainimaging (OFDI) at 1050 nm, in combination with post-image processingmethods, for the detection of type I choroidal neovascularization(CNV) in patients with age related macular degeneration.

 

Methods:

 

An OFDI system consisting of a swept laser with a bandwidthof 64nm centered at 1050nm was developed. Patients were imagedbefore treatment with ranibizumab, and subsequently imaged following4-8 treatments. The 3D image sets were processed with an anisotropicdiffusion filter to reduce noise and enhance edge contrast.The subretinal fluid, intra-retinal edema and CNV volumes weresegmented using connected threshold and level-set semi-automatedalgorithms. Enface images from the OFDI cross sections wereco-registered with color fundus photography (CFP) and fluoresceinangiography (FA), in addition to compiling CNV thickness maps.

 

Results:

 

In post treatment scans, the subretinal fluid and retinal edemavolumes were dramatically reduced if not completely absent,as well as a reduction in the CNV volume (see table). The CNVthickness maps correlate to the areas corresponding to confirmedand suspected CNV on FA.

 

Conclusions:

 

The detailed images of the retina and choroid allow for obtainingvolumetric measurements of abnormal structures characterizingAMD using post-image processing methods. This technology maycontribute to early non-invasive diagnosis of AMD, and potentiallyserve as a valuable post-treatment monitoring tool.  

 

 

Keywords: age-related macular degeneration • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • image processing