Wide Retinal Thickness Mapping Using Mosaic Three-Dimensional Spectral-Domain Optical Coherence Tomography for the Detection of Retinal Nerve Fiber Layer Damage in Glaucoma

Abstract

 

Purpose:

 

To create wide retinal thickness maps, using mosaic technique with three-dimensional (3D) spectral-domain optical coherence tomography (SD-OCT) and compare mosaic mapping with digital fundus photography for the subjective assessment of retinal nerve fiber layer (RNFL) damage in glaucoma diagnosis.

 

Methods:

 

We examined 44 eyes of 30 glaucoma patients by 3D SD-OCT and digital color fundus photography (3D OCT-1000, Topcon). Raster scan protocol of 512 × 128 covering a 6 × 6 mm square area was used to obtain a single 3D scan. To obtain a set of 3D image pieces for 3D mosaic creation, the 3D scans were applied to 4 different square areas that collectively covered an 11 × 11 mm area that included the macula and optic disc. Each 3D image piece was registered on the corresponding part of the color fundus photographs to create a mosaic 3D-OCT image, guided by the vascular network patterns in the OCT projection images and color fundus photographs. Two glaucoma experts (TO and FH) assessed RNFL defects or thinning in each superior and inferior hemifield, using color fundus and converted red-free monochromatic photographs (Figure A, B) and total retina and RNFL thickness mosaic maps (Figure C, D).

 

Results:

 

Of 88 hemifields, 30 were classified as affected and 58, as intact, according to Anderson and Patella’s criteria in static automated perimetry. The sensitivity/specificity of mosaic 3D-OCT thickness mapping and digital fundus photography were 86.7%/82.8% and 56.7%/84.5%, respectively. The sensitivity of mosaic 3D-OCT thickness mapping was significantly higher than that of fundus photography (P = 0.0077, McNemar test), whereas no significant difference was seen in their specificities (P = 1.000, McNemar test).

 

Conclusions:

 

Our results show that mosaic 3D-OCT thickness mapping is more sensitive than digital fundus photography in detecting glaucomatous RNFL damage.  

 

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • nerve fiber layer • imaging/image analysis: clinical