Comparisons of Effective Fields of Two Ultra-Widefield Ophthalmoscopes, Optos 200Tx and Clarus 500

Table 2

Number of three gradings, C > O, C = O, or C < O based on the highest number of traceable vessel branch by the two raters in the four retinal quadrants.

	Number of “O > C”	Number of “O = C”	Number of “O < C”	Kendall’s coefficient of concordance
Upper temporal (Rater 1/Rater 2)	41/35	36/42	13/13	0.79
Lower temporal (Rater 1/Rater 2)	27/22	41/49	22/19	0.79
Upper nasal (Rater 1/Rater 2)	22/20	48/55	20/15	0.81
Lower nasal (Rater 1/Rater 2)	12/11	45/51	33/28	0.79

An image was graded as “O > C” when the highest number of traceable vessel branch was larger in the Optos image than in the Clarus image. An image was graded as “O < C” when the highest number of traceable vessel branch was larger on the Clarus image than on the Optos image. An image was graded as “O = C” when the highest number of traceable vessel branch was equal in the Optos and Clarus images. Inter-rater reliability in the grading of the image into “O > C,” “O < C,” or “O = C” by the two raters was assessed using Kendall’s coefficient of concordance.