Choroideremia - OCT angiography offers anatomic insights
Cheryl Guttman Krader
Published: Thursday, September 1, 2016
INHERITED BLINDING DISEASE
Dr Gao, a postdoctoral research fellow, noted that the accomplishment opens the door to better understanding the pathophysiology of the inherited blinding disease and ultimately to new treatments. Progressive vision loss in eyes with choroideremia occurs because of atrophy of the photoreceptors, retinal pigment epithelium (RPE), choriocapillaris, and choroid, but the sequence in which these different layers degenerate is unclear, in part because of difficulty visualising the choriocapillaris, he explained. “Using the flow signal, local standard deviation of the flow signal, and other image processing tools, we have been able to use OCTA to differentiate intact choriocapillaris from choroidal vessels and projection artefacts in eyes with choroideremia. Application of this approach should enable insight as to the primary sites and progression of cellular degeneration that is needed as a foundation to develop novel therapies,” he noted.PROCESSING FILTERS
OCTA was performed using a spectral domain system (RTVue XR, Optovue) with the split-spectrum amplitude-decorrelation angiography (SSADA) algorithm to detect blood flow. Two types of image processing filters – a local standard deviation filter and a Gabor directional filter – were used to overcome shadowing and flow projection artefacts that create false signals, confounding interpretation of OCTA and the ability to identify intact choriocapillaris. A general linear model for detecting intact choriocapillaris was developed by fitting the image processing output to manual interpretation from an expert grader, using a training set of images from six eyes of four subjects with choroideremia. Its performance was validated using images from an independent cohort of 27 eyes of 15 patients with choroideremia. Subsequently, the technique was used in conjunction with en face OCT to study the extent of structural alterations of the choriocapillaris, RPE, and photoreceptors in eyes of patients with choroideremia. As was reported in their published paper (Jain N, et al. JAMA Ophthalmol. 2016;134(6):697-702), photoreceptors were seen to be preserved at sites overlying intact choriocapillaris. RPE and choriocapillaris were absent beneath outer retinal tubulations, which were present in all eyes with choroideremia, but longer and more numerous in more severely affected eyes. Simon Gao: gasi@ohsu.eduTags: choriocapillaris, optical coherence tomography
Latest Articles
Glaucoma Treatment Under Pressure
New techniques and technologies add to surgeons’ difficult decisions
Outside the Box, Inside the Pipeline
Researchers are tackling glaucoma diagnosis and treatment from all sides.
The EHDS Is Ready for the Green Light
If proposal is approved, Europe could see better access to, and exchange and use of, health data.
From Lab to Life: Corneal Repair Goes Cellular
Long-awaited cellular therapies for corneal endothelial disease enter the clinic.
Balancing Innovation and Safety
Ensuring access to advanced cell therapies amid regulatory overhaul.
With Eyes on Its Future, ESCRS Celebrates Its Past
Winter Meeting offers opportunities to experiment with new concepts and formats.
Best of ESCRS Winter Meeting 2024
Following the New Generation
EDOF IOLs an option for eyes with mild comorbidities, showing potential in mini-monovision strategies.
Refocus on Multifocals
Trifocal IOLs continue to improve as consensus grows regarding indications and contraindications.
Common Myths in Presbyopia Correction
Patient education key to satisfaction with refractive IOLs.