Feasibility of fundus imaging in cataractous eyes by Retinal Health Assessment System

Objective

To study the ability of the Retinal Health Assessment (RHA) system to obtain fundus images in patients with different types and degrees of cataracts.

Methods

A cross-sectional study was performed.Forty-five eyes of 41 patients with cataract were enrolled in First People’s Hospital, Shanghai Jiaotong University from December 2016 to January 2017.Lens opacity grading and RHA fundus imaging were performed after pupil dilation.Forty-five eyes were divided into 4 groups according to the degree of lens opacity: cortical cataract group 18 eyes, nucleus cataract group 21 eyes, posterior subcapsular cataract group 2 eyes, hybrid cataract group 4 eyes.Fundus images were obtained by FullSpectrum mode of RHA2020, and the clearness of fundus images was evaluated.Scores of fundus images clarity were compared between the cortical cataract group and nucleus cataract group.This study was approved by the Ethics Committee of First People’s Hospital, Shanghai Jiaotong University.Written informed consent was obtained from each patient prior to any medical examination.

Results

In all 45 eyes, the phacoscotasmus classification ranged from mildest (C0N2P0, 1 eye) to very serious (C2N5P2 and C4N2P4, 2 eyes). The grade Ⅳ nuclear opacity, grade Ⅲ cortical opacity, and grade Ⅲ posterior subcapsular opacity reduced the quality of RHA images significantly, especially for images with red and green light.In cortical cataract group, images showed peripapillary vessels and retinal vessels at 580 nm and 590 nm, while retinal and choroidal vessels, as well as choroidal pigmentation, were visible at 810 nm.The clarity scores at 580, 590 and 810 nm were 2.0 (1.0, 3.0), 2.0 (2.0, 3.0) and 2.0 (2.0, 3.0), which were lower than that with red and green light (620 nm + 550 nm) (3.0[2.0, 3.0]), with statistically significant differences (all at P<0.05). In nucleus cataract group, the quality of fundus images from the eyes with grade Ⅲ nucleus cataracts was good, the image quality decreased when the nucleus opacity was grade Ⅳ, retinal vessels were occasionally observed at 580 nm and 590 nm.Additionally, retinal and choroidal vessels and choroidal pigment were visible at 810 nm and 850 nm.The clarity scores at 580, 590, 810 and 850 nm were 1.0 (1.0, 3.0), 2.0 (1.0, 3.0) and 2.0 (1.0, 3.0), which were lower than that with red and green light (620 nm + 550 nm) (3.0[1.5, 3.0]), with statistically significant differences (all at P<0.05). In posterior subcapsular cataract group, the retinal vessels were visible at 580 nm, meanwhile retinal and choroidal vessels and choroidal pigment could be observed at 810 nm and 850 nm.In hybrid cataract group, running lines of retinal vessels could be seen at 850 nm, while the central reflection was absent.Focal choroidal vessels were observed.

Conclusions

Except for severe cases, RHA system can produce good quality fundus images in cataract eyes at 580, 590, 810 and 850 nm, facilitating the evaluation of fundus disease before surgery and prediction of visual outcomes after surgery.