Abstract
Purpose :
Retinitis pigmentosa is a common hereditary retinal dystrophy that results in progressive loss of photoreceptors and retinal pigment epithelium. The ocular blood circulation has shown to be altered in RP. Optical coherence tomography based microangiography (OMAG) is a non-invasive imaging modality, capable of acquiring 3 dimensional retinal and choroidal microvascular maps without the use of exogenous dye. In this study we evaluated the retinal and choroidal microvascular architecture and circulation in different stages of RP using OMAG.
Methods :
Thirteen patients (twenty six eyes) with different stages of Retinitis Pigmentosa underwent complete eye examination including slit lamp examination, fundus examination, Goldmann visual fields and imaging tests as part of the evaluation. Imaging testing options include color fundus imaging, FA imaging and Heidelberg Spectralis OCT and OMAG. In assessing visual fields, they were scored according to their results of Goldmann perimetry. OMAG was performed by Zeiss spectral domain OCT-angiography prototype using a 6 mm X 6 mm field of view around macular region. The resulting retinal image was segmented into two layers: the inner retinal layer from the ganglion cell layer to the inner plexiform layer, the deeper retinal layer from the inner nuclear layer to the external limiting membrane. The choroidal image was segmented into choriocapillaris and choroidal layers. The vascular distribution in each layer was depicted as an enface image.
Results :
In all RP patients imaged by OMAG, abnormal microvasculature was detected in both the deeper retinal vasculature layer (from the inner nuclear layer to the external limiting membrane) and the choroidal vasculature. The OMAG results correlated very well with goldman visual field finding and with reduced choroidal-retina thickness measured by Zeiss SD-OCT angiography prototype in RP patients.
Conclusions :
OMAG is a new, non-invasive imaging modality that can evaluate the architecture and circulation of the retina and choroid. It provided detailed, depth-resolved information of the microvasculature changes in Retinitis Pigmentosa. OMAG showed progressive loss of microvascular architecture and decrease blood flow in the choriocapillaris, and deeper retinal vascular layer with progression of RP. This imaging modality may be useful as a novel screening method to evaluate the progression of the RP.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.