We developed an eye phantom that mimic retinal layers and blood vessels to evaluation of retinal OCT-angiography and fundus angiography. The phantom was made of polydimethylsiloxane and titanium dioxide using spin coater and microelectromechanical system (MEMS) technology.
Optical coherence tomography (OCT) is one of useful diagnostic devices for retinal diseases. Recently, optical coherence tomography based angiography (OCTA) extends the OCT applications from structural images to functional images by enabling blood vessel networks mapping. As the use of OCT and OCTA increases in ophthalmology, it is necessary to develop retinal phantoms for performance evaluation of clinical OCT devices for retinal imaging.
In this study, we have developed a retinal layer-mimicking phantom including microfluidic channels to assess OCT and OCTA image quality and to evaluate software accuracy. The phantom is constructed of thin scattering films based on polydimethylsiloxane (PDMS) and titanium dioxide (TiO2) powder. We adjusted TiO2 particle concentration in PDMS for matching intensity of retinal OCT images. Particles were well dispersed throughout PDMS using a probe tip sonicator. Mixed PDMSs were carried out spin coating on a glass slide to make thin films. Before spin coating, silane was applied to the glass substrate to provide a hydrophobic coating for easily removing of cured PDMS. After spinning, thin filmed PDMSs were cured. Microfluidic channels were also made with PDMSs mixed with TiO2 powder, and were designed with sizes of 50 um, 100 um, and 200 um. thin films of cured PDMS were stacked on microfluidic channels. We used diluted dye liquids containing microbeads to occur optically scattered liquid flow like blood vessel. Dye liquids containing microbeads were flowed into an inlet port of the channel through a syringe pump
Finally, we successfully obtained cross-sectional volumetric OCT and OCTA images of completed retinal phantom using lab-made OCT system and clinical OCT system.