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.
High myopia has a high genetic tendency, it not only shows in the excessive elongation of the axial length, but also lends to the formation and progression of various eye lesions, such as peripheral retinopathy, optic disc changes, posterior staphyloma, and myopic maculopathy, due to the mechanical stretching of the axial length to the ocular structure. In addition, high myopia increases the risk of several complications, such as glaucoma, cataract, and corneal disease. All these pathological changes will affect visual function and lead to irreversible vision impairment and blindness in the future. Therefore, it is important to pay attention to screening for optic disc abnormalities and posterior staphyloma, and regular monitor the changes of fundus, intraocular pressure, and lens. At the same time, high myopia has an impact on personal life such as study, psychology, sport, and work, and can reduce the quality of life as well as increase the cost of health care. The clinic should pay more attention to high myopia, prevent and control the development of high myopia from an early stage, in order to minimize its impact on ocular structure and visual function as well as its hazard to personal life and society.
ObjectiveTo investigate the prevalence and risk factors of tessellation fundus (TF) among Tianjin Medical University students with different refractive statuses. MethodsA cross-sectional study. From September to December 2019, 346 students from Tianjin Medical University were randomly selected and underwent slit-lamp examination, non-cycloplegic auto-refraction, subjective refraction, best-corrected visual acuity, ocular biometric measurement, and non-dilation fundus photography. The differences in the prevalence of TF in basic characteristics and ocular biometric parameters were compared. Based on the equivalent spherical (SE), refractive status was divided into the non-myopia group (SE＞－0.50 D) and the myopia group (SE≤－0.50 D). The myopia group was further divided into mild myopia group (－3.00 D＜SE≤－0.50 D), moderate myopia group (－6.00 D＜SE≤－3.00 D), and high myopia group (SE≤－6.00 D). According to the axis length (AL), the subjects were divided into AL＜24 mm group, 24-26 mm group, and ＞26 mm group. The logistic regression was used to analyze the risk factors affecting TF. Trend tests were performed for each risk factor and TF. ResultsOf the 346 subjects, 324 (93.6%, 324/346) were myopia, of whom 73 (21.1%, 73/346), 167 (48.3%, 167/346), and 84 (24.3%, 84/346) were mild myopia, moderate myopia, and high myopia, respectively; 22 (6.4%, 22/346) were non-myopia. There were 294 (85.0%, 294/346) students with TF in the macula, including 9 (40.91%, 9/22), 58 (79.45%, 58/73), 145 (86.83%, 145/167), and 82 (97.62%, 82/84) in non-myopia, low myopia, moderate myopia, and high myopia group, respectively; 52 (15.0%, 52/346) students were without TF in the macula. There were statistically significant gender differences (χ2=4.47), SE (t=6.29), AL (t=－8.29), anterior chamber depth (Z=－2.62), lens thickness (Z=－2.23), and average corneal radius (Z=－3.58) between students with and without TF in the macula (P＜0.05). Spherical equivalent and axial length were independent risk factors for TF and its severity (P≤0.001). With an increasing degree of myopia, and increasing axial length, the risk of TF increased (P for trend＜0.001). ConclusionsThe prevalence of TF is 85.0% among Tianjin Medical University students. TF is detected in the fundus of no myopia, mild myopia, moderate myopia and high myopia. The degree of myopia is higher, the AL is longer, the possibility of TF is higher.