Zeiss, Heidelberg, RTVue, Topcon), and diagnostic testing including terms for diagnostic evaluative tests (ie. Specific keywords used in the search included terms for glaucoma, optical coherence tomography, imaging device manufacturer (ie. The following bibliographic databases were searched: MEDLINE ® (Ovid MEDLINE(R) Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Ovid MEDLINE(R) Daily, Ovid MEDLINE and Versions(R)), EMBASE ® (Embase Classic+Embase), CINAHL ®, Cochrane Library ® (Wiley Library), Web of Science ®, and BIOSIS ®. Published and unpublished studies were considered. Any study providing information on area under receiver operating characteristic curve, sensitivity, specificity, negative predictive value, positive predictive value, likelihood ratio, or diagnostic odds ratio was included. There was no specified search start date. An electronic search strategy was developed through consultation with an experienced ophthalmologist specializing in glaucoma management. The search strategy for this investigation was comprehensive, aiming to retrieve the largest possible number of relevant studies. The aim of this meta-analysis was to provide pooled estimates for the accuracy and detection capability of the most commonly used OCT imaging devices (Zeiss Cirrus OCT, Zeiss, Stratus OCT, Heidelberg Spectralis, Optovue RTVue, Topcon 3D-OCT) for glaucoma diagnosis and classification between patients and healthy individuals. It is unclear however which OCT device should be selected by practitioners when making referral or treatment decisions. also provide images obtained from each of the OCT systems. The technical features of these various systems have been described elsewhere. Segmented analysis is purported to have better diagnostic ability for glaucoma than total retinal thickness, and may be comparable to RNFL thickness.Ĭurrently, several OCT devices are available on the market, each with unique technologies purported to provide better clinical information to the user. Spectral-domain (SD) OCT (Zeiss Cirrus, Heidelberg Spectralis, Optovue RTVue, Topcon 3D-OCT) allows for measurement of specific retinal layers implicated in the pathogenesis of glaucoma, namely: macular nerve fiber layer (mNFL), ganglion cell layer with inner plexiform layer (GCIPL), and ganglion cell complex (GCC) (composed of mNFL and GCIPL). The older time-domain (TD) OCT devices, such as Zeiss Stratus, were able to only measure total macular thickness, which had been shown to have poorer glaucoma diagnostic accuracy than RNFL thickness. To overcome some of these disadvantages, the macular thickness has been proposed as a means of glaucoma detection– 50% of RGCs are found in the macula, and RGC bodies are thicker than their axons, thus are potentially easier to detect. Peripapillary RNFL analysis is the most commonly used scanning protocol for glaucoma diagnosis, as it samples RGCs from the entire retina however, it does suffer certain drawbacks related to inter-patient variability in ONH morphology. OCT is highly reproducible, and is thus widely used as an adjunct in routine glaucoma patient management. An interferometer (beam splitter) is used to record the path of scattered photons and create three-dimensional images. Low coherence infrared light is directed toward the tissue being imaged, from which it scatters at large angles. Image acquisition is analogous to ultrasound, where light waves is used in lieu of sound waves. OCT is a non-invasive, non-contact imaging modality that provides high-resolution cross-sectional imaging of ocular tissues (retina, optic nerve, and anterior segment). However, imaging technologies such as optic coherence technology (OCT) are playing an increasing role in glaucoma diagnosis, monitoring of disease progress, and quantification of structural damage. The currently accepted gold standards for glaucoma diagnosis are optic disc assessment for structural changes, and achromatic white-on-white perimetry to monitor changes in function. Early diagnosis and treatment of glaucoma has been shown to reduce the rate of disease progression, and improve patients’ quality of life. Glaucoma is a multifactorial, chronic optic nerve neuropathy that is characterized by progressive loss of retinal ganglion cells (RGC), which leads to structural damage to the optic nerve head (ONH), retinal nerve fiber layer (RNFL), and consequent visual field defects. Glaucoma is one of the leading causes of blindness in working-age populations of industrialized nations, and is the most common cause of permanent vision loss in persons older than 40 years of age, after age-related macular degeneration. As the population continues to age, and average life expectancies increase, the prevalence of this debilitating disease will grow. Glaucoma is the leading cause of irreversible blindness worldwide.
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