Purpose: To examine the correlation between the van Herick system and the Shaffer system in a large-scale epidemiological survey conducted on healthy Japanese subjects.
Methods: The van Herick technique was performed on 14,779 subjects aged 40 years and over who participated in an ophthalmic epidemiological survey conducted in Tajimi City, Gifu Prefecture. Eyes classified as grade 1 or 2 according to the van Herick technique were diagnosed as narrow angle eyes, and those eyes were subjected to secondary examination using a gonioscope. In the secondary examination, glaucoma specialists evaluated angle width based on the Shaffer system.
Results: Nine hundred and twenty-three eyes of 505 subjects (108 men and 397 women) were determined to be narrow-angle eyes among the 14 779 subjects surveyed. There were 78 grade 1 eyes and 845 grade 2 eyes. Three hundred and eighty-three subjects (75.8%) underwent gonioscopic examination, and 426 eyes (65.9%) had an angle as narrow as or narrower than Shaffer grade 2. Among the 51 eyes evaluated as van Herick grade 1, 44 (86.3%) had an angle an narrow as or narrower than Shaffer grade 2, while among the 595 eyes evaluated as van Herick grade 2,382 (64.2%) had an angle as narrow as or narrower than Shaffer grade 2.
Conclusions: The van Herick technique closely coincided with the Shaffer system and was found to have a potential for use as a simple method for evaluating narrow-angle eyes in Japanese.