Abstract
Purpose:
To develop a simple methodology for recording Retro-dots (Rds), a special type of lens opacity unfamiliar to many clinicians, by using a prototype CEI camera system through comparison with the EAS-1000 (NIDEK).
Methods:
129 eyes of 71 cataract patients, who visited the Eye Clinic of Kanazawa Medical University Hospital between Feb and Nov, 2012, were selected as the subjects (age: 69.5 ± 8.7 years). In addition to Rds, non-nuclear opacities were also examined. The hand-held CEI camera was mounted on an optical bench with fixation targets attached to the camera body. Retroillumination photography at iris plane with both systems was done under maximal pupil dilation. Image analysis with the EAS was based on built-in anterior segment analysis system and that of the CEI camera, Adobe Photoshop®.
Results:
Rds could be readily recorded and reviewed even by less experienced clinicians. The anterior lens part of Rds and cortical opacities was captured by the EAS, but not the posterior lens part, since the EAS was not designed to record both at the same time; in contrast, the depth-of-focus of the CEI system allowed simultaneous recording of opacities in both locales. Rds documented by the CEI camera and the EAS appeared in 64/129 eyes (49.6%) and 46/129 eyes (35.7%), respectively. Water clefts also could be clearly seen in 36/129 eyes (27.9%) with the CEI system and 23/129 eyes (17.8%) with the EAS. The % area of Rds alone within a 6-mm pupil estimated through the CEI camera and the EAS was 20.3±8.6% and 12.6±7.4%, respectively (p<0.05). And corneal reflection artifact was noted in both types of retroillumination images.
Conclusions:
As with the EAS-1000, images taken by the CEI camera system also yield quantitative information. A big advantage of the CEI system is the relative ease of its operation with the image quality approaching that of the EAS. Corneal reflection also does not pose a problem for an experienced clinician. The impact of Rds on the vision loss is becoming increasing evident - important for determining cataract treatment strategy. And technological improvement is needed to extend the CEI system from a clinical tool into a device similar to EAS-1000 for use in lens research including cataract epidemiology.
Keywords: 445 cataract •
488 crystallins •
550 imaging/image analysis: clinical