ABSTRACT
BackgroundIt is important to measure the corneal curvature, anterior chamber depth (ACD) and axial length accurately for calculating IOL power. The interchange outcomes from different measuring methods and apparatus will cause unreliable IOL power. ObjectiveThe present study was to compare the differences of corneal curvature, anterior chamber depth (ACD) measured by IOLMaster and Orbscan Ⅱbefore and after laser in situ keratomileusis(LASIK) and further compare the axial length measured by IOLMaster and A-ultrasound. Methods One hundred and thirty eyes from 65 consecutive myopic patients before LASIK and 56 eyes of 28 cases with 1-month follow-up duration after LASIK in Henan Eye Institute were enrolled in this study. The K value, ACD between IOLMaster and Orbscan Ⅱ as well as results of axial length between IOLMaster and A-ultrasound were compared by using paired t test. The agreements of the measured values among IOLMaster, Orbscan Ⅱ and A-ultrasound were evaluated using Bland-Altman plot. ResultsBefore LASIK,the K value measured by IOLMaster,Orbscan Ⅱ were ( 43.32 ± 1.52 ) D and ( 42.99 ± 1.45 ) D respectively with the difference value of( 0. 33 ±0. 03 ) D, showing a significant difference(t=10. 380,P=0.000) and a positive relation between them(r=0.971,P=0.000). After LASIK,the K value measured by IOLMaster, Orbscan Ⅱwere(39. 02±2. 14) D and ( 38.91 ±2. 04) D with the difference value (0. 12±0. 33 ) D, presenting a significant differences between them (t =2.715, P =0.009). Bland-Altman plots indicated the disagreement in K value and uninterchangeable. Before LASIK, the ACD measured by IOLMaster,Orbscan Ⅱ and A-ultrasound were ( 3.72 ± 0. 22 ) mm, ( 3.69 ±0. 22 ) mm and ( 3.75± 0.27 )mm respectively and no significant differences were found between them (P ＞ 0. 05 ). Axial length measured by IOLMaster significantly prolonged in comparison with A-ultrasound(25.59± 1. 01 mm vs 25.22±0.99 mm ) , and the difference was( -0. 37 ±0. 30 ) mm, showing significant difference ( t =- 14. 098, P =0. 000 ) and positive correlation ( r =0. 954, P =0. 000 ). Axial length values measured by IOLMaster were ( 25.54 ± 1.05 ) mm in preoperation and ( 25.48 ± 1.01 ) mm in postoperation with the difference (0.052±0. 412)mm, showing statistically insignificant difference between them (t=0. 946,P=0. 348). ConclusionsKeratometries measured by IOLMaster,Orbscan Ⅱ are much more different. Therefore,these two methods are not recommended to use interchangely. ACD measured by IOLMaster,Orbscan Ⅱ and A ultrasound are proved to obtain the similar results and is clinically interchange. Axial length measured by IOLMaster is longer than that measured by A-ultrasound.
ABSTRACT
Background Human limbal allograft transplantation or limbal autograft transplantation are the primary approaches to the severe corneal-blindness,but their application in clinic were limited because of the defects of donor material.With the development of tissue engineering technology,transplantation of in vitro cultured limbal epithelial stem cells is being an advanced management.Objective The aim of this work was to expand human limbal epithelial stem cells ex vivo under the guidance of confocal microscope and to lay the foundation for fabricating ex vivo cultured cell sheets.Methods Ten eyes of ten patients were examined with the Heidelberg Retina Tomography Ⅲ Rostock Cornea Module(HRT3-RCM)to elucidate the structure of the human corneoscleral limbus and to correlate limbal epithelial dimensions.According to the analysis of the images of limbal epithelia,the limbal tissues provided by Eye Bank of Henan Eye Institute were cut into suitable explants.Then,this study was conducted to expand limbal epithelial stem cells ex vivo on denuded amniotic membrane.The phenotypes of primary cultured cells were evaluated by morphology and immunofluorescent staining with antibodies for limbal epithelial stem cell markers (p63,cytokeratinl9)and differentiation markers(keratin 3,involucrin).This experimental procedure was approved by the Ethic Committee of Henan Provincial People's Hospital.The written informed consent was obtained from subjects before initiation of any examination.Results The palisade morphology of human limbus was imaged clearly on the laser scanning in vivo confocal microscopy and many hyperreflective cells were observed in palisade basal cells.The cell-island phenomenon was seen in the basement membrane under the laser scanning in vivo confocal microscopy.The oblique sections of limbus showed many papilla-like epithelial columns below the superficial limbal epithelia.Throughout the experiment duration,the epithelial cells grew well with the migration rates from limbal tissue (68.62± 16.94)％ and the migration time(5.83 ±2.04)days,which depended on the tissue freshness.Compared with the second and forth batch of tissue,the migration rates of the third and sixth batch of tissues were significantly higher(P＜0.05),and the migration time was evidently longer in the forth and sixth batch of tissue compared with the first,second,third and fifth batch(P＜0.05).The positively expressing rates in the cultured corneal stem cells were 4.05％ and 36.52％ for p63,26.07％ and 40.55％ for CK19,57.88％ and 40.81％ for K3,64.66％ and 59.19％ for involucrin.Conclusion Human limbal epithelial stem cells can be successfully and purposefully obtained from the limbal tissue based on the guidance confocal miscroscope.The cultured corneal stem cells can grow well on the denuded amniotic membrane