Comparison of axial length and anterior chamber depth obtained by A scan ultrasonography and IOL Master in different axial length groups / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To evaluate the repeatability of axial length (AL) and anterior chamber depth (ACD) obtained by A scan ultrasonography, and to compare AL and ACD obtained by A scan with those obtained by IOL Master.METHODS:Two hundred and fifty-seven cataract eyes of 170 patients were included.IOL Master and A scan were performed for each eye.Five measurements of IOL Master and 3 measurements of A scan were obtained.All the tested eyes were divided into 5 groups according to AL obtained by A scan:Group A (2129mm, 21 eyes).Cronbach's Alpha coefficient and intraclass correlation coefficient (ICC) were applied to evaluate the repeatability of AL and ACD obtained by A scan.Paired t test and Pearson correlation coefficient were used to analyze the differences and correlations of AL and ACD obtained by the 2 devices, respectively.Bland-Altman plots were presented to analyze the agreements of AL and ACD obtained by the 2 devices.RESULTS:All the Cronbach's Alpha and ICCs of AL and ACD values were more than 0.98.The differences of AL values between A scan and IOL Master were-0.11±0.08mm in Group A,-0.15±0.10mm in Group B,-0.19±0.15 mm in Group C,-0.29±0.16mm in Group D and-0.45±0.29mm in Group E, respectively (all P0.89, all P<0.01).CONCLUSION:The AL and ACD values in cataract eyes obtained by A scan were repeatable.The AL and ACD values obtained by A scan were smaller than those obtained by IOL Master.With the increase of AL values, the differences of AL values between A scan and IOL Master increased.

Axial Length Change after Implantable Collamer Lens Implantation

PURPOSE: The axial length measurement is an important variable in calculating the intraocular lens (IOL) power in cataract surgery. In this study, the effects of the implantable collamer lens (ICL) on the axial length measurement were investigated. METHODS: The axial lengths of 141 eyes of 76 highly myopic patients were measured before ICL implantation and 1 month postoperatively using applanation A-scan ultrasound. RESULTS: The measured axial lengths before ICL implantation and 1 month after the surgery were 28.03 +/- 1.91 mm and 28.08 +/- 1.86 mm respectively, with a statistically significant difference of 0.05 mm (p = 0.036). These 2 values showed a high correlation (R2 = 0.9829, p < 0.0001). CONCLUSIONS: Even though the axial length after ICL implantation significantly increased, the 0.05 mm change was too small to influence the determination of the IOL diopters in cataract surgery. Therefore, ICL implantation history may be reflected when measuring the axial length for the IOL power calculation in cataract surgery, but the axial length measured immediately before the cataract surgery may be used to calculate the IOL power regardless of the ICL implantation history.

Measurement of human eye volume in vivo with MRI and its clinical value / 中华实验眼科杂志

Background The quantitative analysis of the relationship between the vitreous volume with diopter and axial length in high myopic eye can offer a valuable basis for relevant clinical research. However, how to measure the ocular volume in vivo is a problem. Objective This study was to measure the eyeball volumes with magnetic resonance imaging ( MRI) and compare the difference of ocular volume between emmetropic and high-myopic eyes in order to explore the influent factors of changes of eyeball volumes. Methods The volumes of ocular anterior segment,lens and vitreous were measured using MRI( 1.5-T) in 60 emmetropic eyes and 60 high-myopic eyes. The ocular axial lengths of the subjects were measured by A-scan ultrasonography. The alterations of vitreous volumes with the changes of axial lengths and diopters were evaluated by linear regression analysis. Written informed consent was obtained from each patient before any medical examination. Results The mean diopters of high myopic eyes was ( - 15. 62 ± 8. 27 ) D and the mean axial lengths were ( 28. 68 ± 2. 68 ) mm, showing a significantly positive correlation between them(R2=0. 830,P = 0. 000). The mean total ocular volumes were(7.46±0. 89)ml3 and those of vitreous were ( 6. 90 ± 0. 8 ) ml3 in the high-myopic eyes with a significant increase in comparison with emmetropic eyes [ ( 6. 00 ± 0. 35 ) ml3 and ( 5. 41 ±0. 32 ) ml3 ] ( t = - 11. 846, P = 0. 000; t = - 12. 1, P = 0. 000 ). However,no significant differences were found in the anterior segment volumes and lens volumes between high myopic eyes and emmetropic eyes (t = 1. 23, P = 0. 220; t = -0. 483 , P = 0. 630 ). The vitreous volumes of high myopic eyes were significantly correlated with the diopters and the axial lengths (R2 =0. 75 ,P = 0. 000 ;R2 =0. 85 ,P = 0. 000) ,and so were the total ocular volumes (R2 = 0. 7543, P = 0. 000; R2 = 0. 8413, P = 0. 000). Conclusion The alteration of vitreous volumes is a mainly cause of difference of total ocular volume in ammetropic eyes. In high myopic eye, vitreous volume has a good linear correlation with refractive error and axial length, which may offer valuable information for vitrectomy.

Ultrasonographic Measurement of Upper Eyelid Thickness in Korean Children with Epicanthus

PURPOSE: Upper eyelid thickness was measured to determine whether there is a difference in the thickness of the upper eyelids in children with and without epicanthus. METHODS: Children were enrolled into the epicanthus group or non-epicanthus (control) group. The children with epicanthus were classified into four subgroups according to the Duke-Elder's classification. The thickness of the upper eyelid was measured at five points with A-scan ultrasonography. RESULTS: There was no significant difference in upper eyelid thickness between the epicanthus group and control group (P>0.05) or between the subgroups of the epicanthus group (P>0.05). CONCLUSIONS: This result suggests that the etiology of epicanthus may not be hypertrophy of soft tissue.

The Relationship of Axial length and Peripheral Retinal Degeneration

To investigate the relationship between peripheral retinal degeneration and axial length, we conducted a clinical study on 254 subjectives (508 eyes) whose age lie between 19-25 years and who had no other ocular disease nor any previous eye surgery. Axial length was measured with A-scan ultrasonography and retinal periphery was inspected by 360 degrees biomicroscopic examination with Goldmann three-mirror lens. The recorded degenerative peripheral retinal lesions were; lattice degeneration, pigmentary degeneration, cystoid degeneration, white without pressure, retinal hole or tears, retinal detachment, posterior vitreous detachment. The statistical analysis was done by using the chi-square test. The mean axial length was 24.01 +/- 1.08mm with a range of 21.8 to 27.9mm. The overall prevalence of the peripheral retinal degenerations increased as axial length did. Specially, that of pigmentary, cystoid, lattice degeneration was significantly related with long axial length individually for each lesion(p<0.01). However, there was a significantly greater percentage(53.37%) of all lesions in 23.0 - 24.9mm axial length group. These results suggest that the frequency of peripheral retinal degeneration increased with axial length but there was a posibility that the peripheral retinal degenerative lesions can be found in eyes of the mean and the shorter axial length.

Biometric analysis of anterior segments of the eye with Scheimpflug Camera according to the type of cataract

We measured the lens thickness and anterior chamber depth on 214 eyes (162 cataract eyes, 52 normal control eyes) using the EAS-1000 Scheimpflug camera. And the results was compared with measurement of A-scan ultrasonography in 49 cataract eyes. The thickness of cataract lens, especially in anterior subcapsular opacities in over 61 years old was significantly thin rather than control lens (p0.05). Lens thickness was increased with age by an annual rate of 0.0l5mm in monnal eyes (p

Surgry of Basic Exotropia designed by Axia| Length Measurement

Recently, the size of the globe has been considered to be an important factor in determining the amount of correction in strabismus surgery. We operated on 88 cases of basic exotropia after measuring the axial length using A-scan ultrasonography. The amount of correction was calculated from the axial length and angle of deviation in each case. At least 2 months postoperatively, 77 cases(87%) had less than 10 prism diopters eso or exodeviation. Favorable results can be expected by introducing the size of the globe in determining the amount of correction in strabismus surgery.

Surgry of Basic Exotropia designed by Axia| Length Measurement

Recently, the size of the globe has been considered to be an important factor in determining the amount of correction in strabismus surgery. We operated on 88 cases of basic exotropia after measuring the axial length using A-scan ultrasonography. The amount of correction was calculated from the axial length and angle of deviation in each case. At least 2 months postoperatively, 77 cases(87%) had less than 10 prism diopters eso or exodeviation. Favorable results can be expected by introducing the size of the globe in determining the amount of correction in strabismus surgery.