Comparison of spectral domain and swept-source optical coherence tomography in pathological myopia

Abstract

To compare optical coherence tomography (OCT) images obtained with swept-source OCT (SS-OCT) and spectral domain OCT (SD-OCT) in pathological myopia. This is a comparative observational cases series. Five patients with pathological myopia underwent SD-OCT and SS-OCT imaging. SS-OCT was performed using a prototype system (Topcon Medical Systems). SD-OCT was performed using enhanced depth imaging on the Heidelberg Spectralis OCT. The closest corresponding scans from the central subfield were compared. Eight eyes of five patients with pathological myopia were included (mean spherical equivalent: -16.00 ± 4.70 D). Overall, SS-OCT better visualized retino-choroidal structures. The choroid, inner segment (IS)/outer segment (OS) line, and external limiting membrane (ELM) were clearly seen in a higher proportion of SS-OCT than SD-OCT scans, (P<0.01 for all) whereas visualization of the sclera and retinal pigment epithelium (RPE) were similar. SS-OCT demonstrated foveoschisis in four eyes, with one of these not visible on SD-OCT. The wider SS-OCT scan revealed additional pathology not visible using SD-OCT along the staphyloma walls in 4/8 images. These included incomplete posterior vitreous detachment in one eye and peripheral retinoschisis in 3/8 eyes. Vitreoschisis was visible in 3/8 SS-OCT images but not in the SD-OCT images. SS-OCT is useful for imaging the posterior staphyloma of pathological myopia, providing greater detail than SD-OCT.