Ultrahigh-resolution optical coherence tomography in glaucoma

Abstract

Objective: Optical coherence tomography (OCT) has been shown to be a valuable tool in glaucoma assessment. We investigated a new ultrahigh-resolution OCT (UHR-OCT) imaging system in glaucoma patients and compared the findings with those obtained by conventional-resolution OCT.

Design: Retrospective comparative case series.

Participants: A normal subject and 4 glaucoma patients representing various stages of glaucomatous damage.

Testing: All participants were scanned with StratusOCT (axial resolution of approximately 10 mum) and UHR-OCT (axial resolution of approximately 3 microm) at the same visit.

Main outcome measure: Comparison of OCT findings detected with StratusOCT and UHR-OCT.

Results: Ultrahigh-resolution OCT provides a detailed cross-sectional view of the scanned retinal area that allows differentiation between retinal layers. These UHR images were markedly better than those obtained by the conventional-resolution OCT.

Conclusions: Ultrahigh-resolution OCT provides high-resolution images of the ocular posterior segment, which improves the ability to detect retinal abnormalities due to glaucoma.

Figure 1

StratusOCT (A) and ultrahigh-resolution optical coherence tomography (B) scans of a normal subject. I, Macular linear scans, whose orientations are depicted in the upper image. II, Peripapillary circular scans. III, Optic nerve head (ONH) linear scans. Inf = inferior; INL = internal nuclear layer; IS/OS = inner segment/outer segment; NFL = nerve fiber layer; ONL = outer nuclear layer; OPL = outer plexiform layer; RPE = retinal pigment epithelium; Sup = superior; Temp = temporal.

Figure 2

A, Optic disc photograph of early glaucomatous damage demonstrating moderate cupping and superior temporal neuroretinal rim thinning. A visual field defect is presented in the inferior nasal region. B, StratusOCT scans. C, Ultrahigh-resolution optical coherence tomography images. I, Thinning of the nerve fiber layer (NFL) and ganglion cell layer is evident in the temporal superior macular scans. II, Arrows highlight focal NFL defects in the peripapillary scans. III, Shallow cupping is evident in the optic nerve head scans. Inf = inferior; Sup = superior; Temp = temporal.

Figure 3

A, Optic disc photograph of moderate glaucomatous damage demonstrating moderate cupping and inferior temporal neuroretinal rim thinning. Superior and inferior arcuate defects are shown in the visual field test. B, StratusOCT scans. C, Ultrahigh-resolution optical coherence tomography images. Marked thinning of the nerve fiber layer (NFL) and ganglion cell layer is evident in both sides of the fovea, most noticeably in the inferior region (I). II, The NFL is attenuated throughout the peripapillary scans. III, Large and deep optic nerve cupping is evident in the optic nerve head scans. Inf = inferior; Sup = superior; Temp = temporal.

Figure 4

A, Optic disc photograph of advance glaucomatous damage demonstrating large cupping and inferior temporal neuroretinal rim thinning with superior hemifield visual field loss. B, StratusOCT scans. C, Ultrahigh-resolution optical coherence tomography. Marked thinning of the nerve fiber layer and ganglion cell layer is evident in both sides of the fovea, most noticeably in the inferior region (I) as well as in the peripapillary scans (II). III, Optic nerve head scans showed deep cupping with elimination of the neuroretinal rim. Inf = inferior; Sup = superior; Temp = temporal.

Figure 5

A, Red-free fundus photograph of a temporal inferior nerve fiber layer (NFL) defect. The visual field shows an early superior paracentral defect. B, StratusOCT scans. C, Ultrahigh-resolution optical coherence tomography (OCT) images. Scanning through the NFL defect shows marked thinning surrounded by a normal-thickness NFL. Arrows depict the extent of NFL thinning in the OCT images.