| [Background]:Axial length (AL) and corneal curvature (K) is an important texture parameters and optical components. Axial length measurements and keratometry are of major importance for the research of refractive errors and the implantation of intraocular lens (IOL) in refractive and cataracta surgery. Recently, IOL-Master which employs partial coherence interferometry (PCI) has been widely recognized in accuracy and repeatability of keratometry, anterior chamber depth and axial length measurements. Comparing with the traditional type A ultrasound methods, IOL-Master which is a noncontact device presents more accurate and convenient results in measuring optical components. Recent advent of Lenstar LS 900 non-contact optical length measuring instrument which employs optical low-coherence reflectometry (OLCR), one measurement of axial length, corneal thickness, anterior chamber depth, lens thickness, corneal curvature of the eye, including the other structural parameters. Foreign literature has been on the Lenstar LS 900 and IOL-Master two optical coherence biometry clinical study. IOL-Master as a present for the non-invasive measurement method has been applied to refractive errors of children. As and can measure more structural parameters of the eye than IOL-Master, Lenstar LS 900 in children's eye development and clinical study of children's refractive error may be greater value. [Objective]:To compare the difference of measurements of Axial length (AL) and keratometry obtained with Lenstar LS 900 and IOL-Master and evaluate the agreement of two instruments.[Methods]:Prospective self-controlled study. Object is September 5 to 26, 2010 in the Provincial Hospital Affiliated to Shandong University of refractive error eye clinic children. Corrected visual acuity of both eyes≥1.0, no history of ocular trauma and surgical history, no strabismus, refractive errors and the exclusion of organic disease other than the eyes of those who participated in this study. Lenstar LS 900 and IOLMaster were used to examine Axial length and keratometry on both eyes. Axial length measurements for each eye 5 times the mean value for statistical Measurement of corneal curvature of each eye 3 times, enter the average corneal curvature [K= (K1+K2)/2] statistics on the average. Difference in measurements of mean keratometry (K) [K=(Kl+K2)/2] and ACD between two methods were assessed using Paired t test. Bland-Altman method was used to evaluate the agreement of two methods.[Results]:56 eyes of 28 individuals were meet the selected standards. Age (6.97±1.81)y/o. Spherical equivalent refraction (+0.70±3.86D). The mean K values were (43.34±1.42)D for Lenstar LS 900 and (43.22±1.44)D for IOLMaster and the difference was significant (P<0.01). The AL were (22.15±2.31)mm for Lenstar LS 900 and (22.13±2.30)mm for IOLMaster and the difference was significant (P< 0.01). The difference of K values and AL values are respective used the Bland-Altmann method for analysis. The mean difference of K values ()was 0.12D, the standard deviation (SD) of difference (Sd)was 0.25D with a probability of 95%, difference in K values did not exceed-0.37～+0.61D and the maximum was 0.55D. The mean difference of AL values ()was 0.02mm, while the SD of difference (Sd) was 0.02mm with a probability of 95%. The difference in K values did not exceed-0.03-+0.06mm and the maximum was 0.03mm. For clinical consideration, these two modalities showed comparable results for both K values and AL.[Conclusion]:Lenstar LS 900 and IOLMaster can be interchangeable on measurement of both K values and AL, especially for IOL calculation. |
PDF Full Text Request