Abstract
Purpose :
Retinitis pigmentosa (RP) is a progressive retinal disease characterized by night blindness and visual field (VF) constriction. Pale optic discs and thin retinal blood vessels are also known as signs of RP. Previous studies suggested that macular microvasculature changes are correlated with central visual function such as visual acuity (VA) and the VF test sensitivites. To the best of our knowledge, no studies have investigated the relationship between visual functions and blood flow density around the optic nerve head (ONH) in patients with RP. The purpose of our current study is to analyze the blood flow density surrounding the ONH of RP patients using optical coherence tomography angiography (OCTA) and to evaluate the correlation between visual function and vessel flow density.
Methods :
Thirty eyes of 30 patients with RP, who demonstrated VF constriction within 10 degrees, were enrolled in the current study. In addition to VA and VF tests (Humphrey Field Analyzer, SITA standard 10-2 program), we measured flow density using OCTA (RTVue XR Avanti) at the macula and surrounding optic discs in multiple layers: superficial, deep and choroid capillary layers at the macula; nerve head, vitreous, radial peripapillary capillaries and choroid/disc around ONH. The binarization of all OCTA images around the ONH was performed with ImageJ software by Niblack’s method. The area assumed to be the ONH in the choroid/disc layer was excluded from the flow density analysis in all layers around ONH. All study protocols adhered to the tenets of the Declaration of Helsinki. This retrospective study was approved by the institutional review board of The University of Tokyo Hospital.
Results :
The mean (±SD) age of the patients was 41.8±14.6 years old. Sixteen patients were male and 14 were female. Mean deviation (MD) of HFA was significantly related to logMAR VA (p<0.05). LogMAR VA was not related to the blood flow density at the macula and around ONH. On the other hand, multivariate regression analyses demonstrated that MD was significantly associated with the flow density of deep retinal layers at the macula (p<0.001). No significant correlation was found between MD and flow density of the superficial retinal or choroidal layer. Moreover, MD was not correlated with flow density around ONH.
Conclusions :
VF deterioration was significantly associated with the flow density of deep retinal layer but not with that around ONH.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.