Objective To evaluate the accuracy of the biometry using immersion B scan and partial coherence interferometry (Lenstar LS900) for the axial length (AL) of silicone oil-filled eyes respectively. Methods Thirty-five silicone oil-filled eyes (38 patients) were included in the study. All of these eyes underwent silicone oil removal, cataract extraction and intraocular lenses implantation. The AL of all the silicone oil-filled eyes was measured with A/B-scan ultrasound and Lenstar LS900 before operation and with Lenstar LS900 after operation. The measured distance was compared respectively. The method of immersion B-scan guided with respective sonic velocity. AL was the sum of corneal thickness, anterior chamber depth, lens thickness, the apparent length of oil bubble (velocity values 996 m/s), the depth of the water layer beneath the oil bubble. Results Thirty-one eyes were measured with Lenstar LS900 before silicone oil removal, and the mean AL was (24.12±1.70) mm, 7 eyes failed to get the results before the operation; 36 eyes were measured with Lenstar LS900 after silicone oil removal, and the mean AL was (24.45±1.89) mm. All eyes were measured with B-scan before silicone oil removal, and the mean AL was (24.87±2.52) mm. The difference (31 eyes) of AL measurement before silicone oil removal by two methods was (−0.00±0.09) mm; the difference (31 eyes) between pre- and post-surgical AL measurement with Lenstar LS900 was (0.02±0.07) mm; the difference (36 eyes) between pre-surgical AL measured with B-scan and post-surgical AL measured with Lenstar LS900 was (−0.02±0.11) mm. All the differences were not statistically significant (t=−0.205, 1.752, −1.280; P＞0.05). The consistency of the results measured by two methods was well in Bland-Ahamn analysis. Conclusions Measurement results of AL between immersion B-scan guided with respective sonic velocity and Lenstar LS900 are high repeatability on silicone oil-filled eyes. The AL of silicone oil-filled eyes can be measured reliably by immersion B-scan guided with respective sonic velocity.
Objective To observe the axial length and anterior chamber depth in eyes with branch retinal vein occlusion (BRVO). Methods Randomly selected 90 eyes of forty-five patients with BRVO were enrolled in this study. There were 25 males and 20 females. The mean age was (46.22±13.45) years. All the patients were underwent examination of visual acuity, slit-lamp microscope, indiophthalmoscope, fundus color photography and fundus fluorescence angiography (FFA). Randomly selected 45 healthy individuals for control group, including 28 males and 17 females. The mean age was (48.24±15.77) years. The axial lengths and anterior chamber depths of affected and fellow eyes of BRVO patients and the eyes of controls were measured using IOL Master. The data were compared by the two sample paired t test. Results The mean axial length of the affected eyes in the BRVO group was (22.69±0.99) mm, and that of the fellow eyes group was (22.78±1.24) mm. The difference in axial length between the affected eyes and fellow eyes in the BRVO group was not significant (t=0.355, P＞0.05). The mean axial length of the right eyes in the control group was (23.38±1.32) mm, and that of the left eyes in the control group was (23.37±1.27) mm. The difference in axial length between the left eyes and right eyes in the control group was not significant (t=0.017, P＞0.05), while the difference in axial length between the affected eyes in the BRVO group and the right, left eyes in the control group was significant (t=−2.563, −2.663; P＜0.05). The mean anterior chamber depth of the affected eyes in the BRVO group was (2.66±0.26) mm, and that of the fellow eyes was (2.65±0.30) mm. The difference in anterior chamber depth between the affected eyes and fellow eyes in the BRVO group was not significant (t=0.089, P＞0.05). The mean anterior chamber depth of the right eyes in the control group was (2.56±0.29) mm, and that of the left eyes was (2.59±0.30) mm. The difference in anterior chamber depth between the left eyes and right eyes in the control group was not significant (t=−0.592, P＞0.05). The difference in anterior chamber depth between the affected eyes in the BRVO group and the right, left eyes in the control group was not significant (t=1.779, 1.778, P＞0.05). Conclusion In the affected eyes of BRVO, the axial length is shorter and anterior chamber depth is normal.