Imaging Vitreomacular Interface Abnormalities in the Coronal Plane
Imaging Vitreomacular Interface Abnormalities in the Coronal Plane
Aim: To describe vitreoretinal imaging of eyes with vitreomacular abnormalities using high-resolution coronal-plane optical coherence tomography (OCT) scanning combined with simultaneous scanning laser ophthalmoscope (SLO) imaging.
Methods: A SLO-OCT (OTI, Canada) was used to scan 835 eyes in 736 patients with vitreomacular interface abnormalities including epiretinal membranes, macular hole, incomplete posterior vitreous detachment, vitreomacular traction syndromes and diabetic and cystoid macular oedema in a retrospective study. The longitudinal-B scan images and the transverse -C scan images in the coronal plane were used to describe vitreomacular interface abnormalities. The SLO-OCT simultaneously produces a confocal image of the retina.
Results: The longitudinal "B" scan and en-face "C" scan images allowed identification of tractive forces of epiretinal membrane, contour of the hyaloid membrane and changes in inner retinal surface. A simultaneously obtained OCT scan and SLO image of the fundus offered exact co-localisation of retinal structures and vitreomacular interface abnormalities.
Conclusion: Scanning the vitreomacular interface by using combined OCT and SLO enables the visualisation and better understanding of various vitreomacular interface abnormalities, due to the ability to colocalise pathology on OCT with retinal vascular landmarks and the ability to visualise pathology from a new perspective, coronal plane parallel to retinal surface.
Optical coherence tomography (OCT) is now a widely used imaging technique in ophthalmology to diagnose various macular and optic nerve conditions since its first report in 1991. Optical coherence tomography achieves two-dimensional cross-sectional imaging of tissue by measuring the echo delay and intensity of back-reflected infrared light from internal tissue structures. Optical coherence tomography enables the direct real-time imaging of retinal pathology that could not previously be visualised in vivo, and so it is described as a non-invasive optical biopsy of the retina. Since the introduction of commercial OCT in 1996, OCT technology has undergone multiple generations of improvement.
OCT has been largely used to create longitudinal images of the eye (analogous to ultrasound B-scan images), which are in-depth measurement through the retina, "i.e. images in the plane (X, Z) or (Y, Z) with the "Z" axis normal to the patient's face." Podoleanu et al, reported an OCT system capable of producing both transverse (en-face) and longitudinal images from the retina in living eye. They developed the combined system of confocal scanning laser ophthalmoscopy to obtain the high-resolution transverse image of retina (fundus view) and OCT to obtain cross-sectional transverse and longitudinal scans. This system produces en-face OCT images and a pixel-to-pixel corresponding transverse image of retina provided by the confocal channel simultaneously to compare them directly. This is achieved by selective capture of different orientations of OCT images at precise points on the confocal image. The optical source used in this combined system of OCT and confocal scanning laser ophthalmoscopy is similar to that in conventional high-resolution longitudinal OCT (Stratus OCT, Carl Zeiss Meditec, Dublin, California), so the depth resolution obtained is also the same, that is 10-15 µm. The recent introduction of several commercial spectral-domain OCT devices has allowed ophthalmologists to obtain three-dimensional high-resolution OCT data.
In this pilot study, we present the clinical evaluation of various vitreomacular (VM) interface abnormalities by using this novel system of combined scanning laser ophthalmoscope and optical coherence tomography. Our purpose is to show examples of visualisation of VM interface pathology in eyes with epiretinal membrane (ERM), VM traction syndrome, macular hole, incomplete posterior vitreous detachment (PVD) and cystoid macular oedema due to VM interface abnormalities like ERM and diabetic macular oedema in the coronal plane (en-face view).
Abstract and Introduction
Abstract
Aim: To describe vitreoretinal imaging of eyes with vitreomacular abnormalities using high-resolution coronal-plane optical coherence tomography (OCT) scanning combined with simultaneous scanning laser ophthalmoscope (SLO) imaging.
Methods: A SLO-OCT (OTI, Canada) was used to scan 835 eyes in 736 patients with vitreomacular interface abnormalities including epiretinal membranes, macular hole, incomplete posterior vitreous detachment, vitreomacular traction syndromes and diabetic and cystoid macular oedema in a retrospective study. The longitudinal-B scan images and the transverse -C scan images in the coronal plane were used to describe vitreomacular interface abnormalities. The SLO-OCT simultaneously produces a confocal image of the retina.
Results: The longitudinal "B" scan and en-face "C" scan images allowed identification of tractive forces of epiretinal membrane, contour of the hyaloid membrane and changes in inner retinal surface. A simultaneously obtained OCT scan and SLO image of the fundus offered exact co-localisation of retinal structures and vitreomacular interface abnormalities.
Conclusion: Scanning the vitreomacular interface by using combined OCT and SLO enables the visualisation and better understanding of various vitreomacular interface abnormalities, due to the ability to colocalise pathology on OCT with retinal vascular landmarks and the ability to visualise pathology from a new perspective, coronal plane parallel to retinal surface.
Introduction
Optical coherence tomography (OCT) is now a widely used imaging technique in ophthalmology to diagnose various macular and optic nerve conditions since its first report in 1991. Optical coherence tomography achieves two-dimensional cross-sectional imaging of tissue by measuring the echo delay and intensity of back-reflected infrared light from internal tissue structures. Optical coherence tomography enables the direct real-time imaging of retinal pathology that could not previously be visualised in vivo, and so it is described as a non-invasive optical biopsy of the retina. Since the introduction of commercial OCT in 1996, OCT technology has undergone multiple generations of improvement.
OCT has been largely used to create longitudinal images of the eye (analogous to ultrasound B-scan images), which are in-depth measurement through the retina, "i.e. images in the plane (X, Z) or (Y, Z) with the "Z" axis normal to the patient's face." Podoleanu et al, reported an OCT system capable of producing both transverse (en-face) and longitudinal images from the retina in living eye. They developed the combined system of confocal scanning laser ophthalmoscopy to obtain the high-resolution transverse image of retina (fundus view) and OCT to obtain cross-sectional transverse and longitudinal scans. This system produces en-face OCT images and a pixel-to-pixel corresponding transverse image of retina provided by the confocal channel simultaneously to compare them directly. This is achieved by selective capture of different orientations of OCT images at precise points on the confocal image. The optical source used in this combined system of OCT and confocal scanning laser ophthalmoscopy is similar to that in conventional high-resolution longitudinal OCT (Stratus OCT, Carl Zeiss Meditec, Dublin, California), so the depth resolution obtained is also the same, that is 10-15 µm. The recent introduction of several commercial spectral-domain OCT devices has allowed ophthalmologists to obtain three-dimensional high-resolution OCT data.
In this pilot study, we present the clinical evaluation of various vitreomacular (VM) interface abnormalities by using this novel system of combined scanning laser ophthalmoscope and optical coherence tomography. Our purpose is to show examples of visualisation of VM interface pathology in eyes with epiretinal membrane (ERM), VM traction syndrome, macular hole, incomplete posterior vitreous detachment (PVD) and cystoid macular oedema due to VM interface abnormalities like ERM and diabetic macular oedema in the coronal plane (en-face view).