Comparison of the accuracy of axial length measurement by different imaging methods in Sprague Dawley rats

Abstract

BackgroundObtaining accurate axial length (AL) is very important for the establishment of animal models of myopia. The purpose of this study is to compare the accuracy of Quantel A-B scan, OD-1 A scan, and vernier caliper in measuring AL in Sprague Dawley (SD) rats.MethodsIn total, 60 5-week-old SD rats were divided into female rat group (n = 30) and male rat group (n = 30). Quantel A-B scan and OD-1 A scan were, respectively, used to measure the AL of both eyes of each living rat, and vernier caliper was used to measure the anterior-posterior diameter of each rat’s eyeball. Besides, the correlation between refractive error (RE) and AL measured by different instruments was evaluated, and the accuracy of the three measurement methods was compared according to gender and left/right eyes.ResultsThere were significant differences in AL and diopter of SD rats at the same age (p < 0.05). the AL of male rats was greater than that of female rats, while diopter (D) was the opposite; There was no significant difference in AL and D between left and right eyes in the same SD rats (p > 0.05); There were statistical differences among the three measurement methods (p < 0.05), AL measured by vernier caliper was the largest, followed by Quantel A-B scan, OD-1 A scan; Difference in AL between male and female was not statistically significant between the results obtained by Quantel A-B scan and vernier caliper (p > 0.05), but there were statistically significant differences between the other two measurement methods (p < 0.05).ConclusionSex is the influencing factor of AL and RE. Imaging measurement can accurately measure the AL in living small rodents. Compared with OD-1 A scan, Quantel A-B scan may be more accurate.

Integrating a Fundus Camera with High-Frequency Ultrasound for Precise Ocular Lesion Assessment

“…We find the axial length of the eye using the following equation, where is the time interval between the corneal peak and the retinal peak and is the speed of ultrasound. The axial length was calculated to be 4.902 mm, which is close to the axial length reported in other studies on a similar strain of rats measured via OCT [ 30 ]. The slight mismatch in axial length from the reported value could be attributed to the fact that the lens encompasses more than 60% of the volume of the eye in rats [ 31 ].…”

Integrating a Fundus Camera with High Frequency Ultrasound for Precise Ocular Lesion Assessment

“…where ∆t is the time interval between the corneal peak and the retinal peak and v is the speed of ultrasound. The axial length was calculated to be 4.902 mm, which is close to the axial length reported in other studies on a similar strain of rats measured via OCT [30]. The slight mismatch in axial length from the reported value could be attributed to the fact that the lens encompasses more than 60% of the volume of the eye in rats [31].…”