RGB Camera-Based Imaging of Oxygen Saturation and Hemoglobin Concentration in Ocular Fundus

Kazuya Nakano,Takashi Ohnishi,Ryosuke Hirofuji,Hideaki Haneishi,Markku Hauta-Kasari,Izumi Nishidate

doi:10.1109/access.2019.2913878

Abstract

We propose a red, green, blue (RGB)-based oximetry to assess the ocular fundus and determine its oxygen saturation (SO2) and hemoglobin concentration. The oxygenated hemoglobin concentration, deoxygenated hemoglobin concentration, and SO2 were estimated employing a method that combines Monte Carlo simulation of light transport in the fundus tissue with a multiple regression analysis. In this study, a single-layer model of the ocular fundus was employed for the Monte Carlo simulation. We constructed an experimental apparatus for measuring the fundus of a rat's eye using an RGB detector and investigated the physiological response that occurs upon a change in the fraction of inspired oxygen (FiO2). The resultant images of oxygenated hemoglobin concentration, deoxygenated hemoglobin concentration, total hemoglobin concentration, and SO2 indicated that the response was caused by the defective oxygenation of the blood. The results of the present study indicate the possibility of oximetry based on the RGB images of a fundus.

Highlights

Observations of the ocular fundus are useful for diagnosing fundus diseases such as age-related macular degeneration (AMD) [1], diabetic retinopathy [2], [3], retinal pigmentary degeneration [4], and retinal vascular occlusions [5]
We propose a noninvasive imaging method for measuring SO2 based on diffuse reflectance spectroscopy with an RGB color detector that is mounted on commercial fundus cameras
We proposed an RGB-based oximetry for the retina

Summary

Introduction

Observations of the ocular fundus are useful for diagnosing fundus diseases such as age-related macular degeneration (AMD) [1], diabetic retinopathy [2], [3], retinal pigmentary degeneration [4], and retinal vascular occlusions [5]. We can observe the vessels in the ocular fundus directly because some parts of the eyeball, such as the vitreous body and the crystalline lens, are transparent. Observations of vessels in the fundus facilitate the diagnoses of fundus disease and various other diseases related to blood vessels in the eye, such as hypertension [6] and kidney disease [7]. Doctors diagnose these diseases qualitatively by observing pictures taken with a fundus camera. It is difficult to extract the specific information of the retina directly from the red, The associate editor coordinating the review of this manuscript and approving it for publication was Sudhakar Radhakrishnan

Methods

Results

Conclusion