Article Date: 7/1/2011

OCT Update

OCT Update

What's new with these must-have devices

By Sean McKinney, Contributing Editor

Bioptigen: Deep Imaging OCT Unit Released for Preclinical Applications

Eric L. Buckland, PhD, CEO of Bioptigen, Research Triangle Park, NC, says his company's Envisu R4300 is a full-range anterior segment imaging system available for pre-clinical applications. The system offers 8-mm imaging depth (as measured in air), four micrometer axial resolution, and 20 mm scan range. The system provides images of the full anterior chamber or the full crystalline lens without artifacts. Imaging speed is 20,000 lines per second, capable of producing high density volumetric scans in three seconds.

“With a change of lens, the system also produces high-resolution images of the retina with a deep depth of field,” he says. The company plans to seek FDA clearance of the Envisu R4300 as a visualization tool to support glaucoma, refractive and cataract therapies, and posterior segment surgery.

Carl Zeiss Meditec: Dense Data That Combines Visualization and Analysis

Marianne Whitby, senior marketing manager at Carl Zeiss Meditec, notes that Cirrus HD-OCT captures a highly dense cube over a 6 mm x 6 mm area. “The cube data is used for both visualization and analysis; no additional scan pattern is needed for analysis,” she says. “The dense data cubes provide the detail needed for analyses to help identify subtle pathology. Tightly spaced B-scans ensure that small areas of pathology are imaged.”

The millions of data points from the cube are fed into proprietary algorithms for accurate segmentation, reproducible measurements and registration for change analysis. The cube data can be viewed from all angles, with 3D rendering, OCT fundus images and customized en face slabs.

Automatic alignment with Fovea Finder and Auto Center features takes pressure off of the operator, she adds. “As long as the scan is roughly placed on the fovea or optic nerve, the software automatically centers the measurements after the capture. This helps to minimize patient chair times and optimize registration and reproducibility.”

Cirrus also provides change analysis for both RNFL and retinal thickness. “Cirrus direct registration ensures precise reproducibility for tracking change,” notes Whitby. Data from the current cube is aligned and rotated as necessary to allow pixel-by-pixel registration for comparisons to the prior visit. Zeiss' Guided Progression Analysis for assessing RNFL change compares RNFL thickness measurements over time and determines if statistically significant change has occurred.

Heidelberg Engineering: Combining Spectralis OCT with HRA

Heidelberg Engineering combined confocal scanning laser ophthalmoscopy with Spectral Domain OCT, creating new 3-D views of the eye using multimodality diagnostic imaging. The Spectralis family of imaging devices now incorporate BluePeak technology, offering blue laser autofluorescence as a standard diagnostic tool for following dry AMD and other retinal diseases.

Opko: Combining Microperimetry with OCT

Notes Rishard Weitz, executive vice president of Opko: “Only Opko offers SD-OCT/SLO combined with Fundus Tracking Microperimetry in one spectral OCT device. Since OCT qualifies and quantifies retinal structural changes, and microperimetry qualifies and quantifies retinal functional changes, the combination of the structure and function detection and follow-up gives the clinician the best tool to evaluate retinal diseases and treatments.”

The confocal scanning laser ophthalmoscope provides high-resolution images and retinal tracking before, during and after the OCT scan. The SLO “Lock and Track” function ensures that follow-up scans are obtained from the same location without relying on the operator's subjective judgment. This feature is designed to dramatically increase test reliability, repeatability and reproducibility. The SLO confocal image automatically tracks and compensates for involuntary eye movements.

Because the SLO confocal fundus image and OCT image share the same pixel-to-pixel correspondent optics, Weitz notes that registration and orientation are precise. The new Opko AC Cornea Lens provides high-resolution Spectral OCT imaging of the cornea and angle.

Optovue: From GCC to Anterior Segment & Portability

Working with David Huang, MD, PhD, Optovue became the first company to develop analysis of the ganglion cell complex to help diagnose and manage glaucoma, according to marketing director Peter Naismith. “Our patented GCC analysis can detect focal and global loss with high predictability,” says Naismith.

The iVue, released in April 2010, is a compact version of the RTVue spectral domain OCT, offering the same scanning speed and resolution as the larger system. Like the stationary RTVue, the portable system also includes scanning and reports for retina, retina nerve fiber and corneal assessment. Some clinicians use the iVue for supine or wheelchair-bound patients. Some surgeons use it during surgery to improve visualization of the posterior segment during procedures.

Optovue has launched iWellnessExam, a pay-per-visit program that allows the practice to obtain an SD-OCT with no money down and no fixed monthly lease. Then, the iVue is incorporated into the comprehensive eye exam. “It can be offered as a co-payment option to patients,” says Naismith. “For $39, or whatever a doctor decides to charge, the patient can decide whether he or she wants the assurance of an examination that could detect early signs of glaucoma, diabetic retinopathy or epiretinal membranes.”

Topcon: Increasing Capability

Robert Gibson says the Topcon 3D OCT 2000 is the only SD-OCT that has a true color fundus camera built into the OCT system. “This allows the doctor to perform a color fundus image at the same time as an OCT image,” he says. “This also allows the doctor to bill out CPT code 92250 rather than 92133 or 92134. The importance of this, of course, is that 92250 now reimburses, in some areas of the country, for about twice as much as the OCT codes. So the doctor will generate more revenue with the Topcon OCT than with other OCT instruments, while achieving the same accuracy in diagnosing and monitoring disease. The color fundus image—along with the OCT image—also help the doctor visualize and communicate the results to the patient.”

Approvals Pending

• FDA approval of Cannon's recently acquired SPOCT-HR has been delayed because of Cannon's acquisition of about 90% shares of Optopol, Inc., according to Anne Nai-Chi Ji, marketing supervisor. Ji says Cannon will offer 3-micron resolution, ultra-high scanning speed (up to 52,000 A-scans per second) and software packages for glaucoma and retinal disease.
• Tomey's anterior segment OCT system uses swept-source OCT, also called optical frequency domain imaging. It's an alternative implementation of Fourier Domain-OCT in which the wavelength of the light source is tuned in rapid cycles. The system, also awaiting FDA approval, provides both high resolution and wide area measurements and a penetration depth of 6 mm.

Other Advances in Imaging

Although not OCT, the laser-based Optos technology provides dynamic, ultra-widefield (200°), ultra-high definition angiography and color imaging. The non-contact simultaneous pole to peripheral view of the retina supports practitioners in diagnosing, analyzing and monitoring ocular pathology that may first present in the periphery of the retina. More than 80% of the retina is captured in a single view, allowing simultaneous evaluation of the peripheral and central retina.

The 200Dx is an upgrade to the established P200 and offers enhanced image quality, allowing easy examination of peripheral areas. It produces improved detail in the macula, brighter superior field illumination and improved visualization of the RNFL. The new 200Tx helps general ophthalmologists and vitreoretinal specialists recognize disease and guides their treatment decisions. It has multiple wavelength imaging, including options for color, red-free, fluorescein angiography and autofluorescence. The 200Tx allows captures of autofluorescent retinal pigment epithelium changes, age-related macular degeneration, branch retinal vein occlusion, non-proliferative diabetic retinopathy, and diabetic retinopathy.

For the optometrist, Optomap Retinal Exam can be used in the clinical evaluation of every patient once a year. The ultra-widefield digital image of the retina reveals important information for the comprehensive evaluation of systemic and ocular health.

Optometric Management, Issue: July 2011