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@#AIM: To observe the changes of the development of the anterior segment in children after the treatment of laser photocoagulation(LP)for retinopathy of prematurity(ROP)by corneal topographic. <p>METHODS: In this retrospective case study, 25 children(50 eyes)as ROP group and 23 children(46 eyes)born at term as control group had participated in the study. The best corrected visual acuity(BCVA)was examined in both groups, and converted to LogMAR vision when statistical analysis was performed. The observation indicators of the Sirius anterior segment analysis system in the study were as follows: the horizontal iris diameter(HVID), corneal radius of the thinnest point, the thinnest point of the cornea, the maximum curvature of the cornea, the maximum radius of cornea curvature, central corneal thickness(CCT), corneal volume(CV), anterior chamber depth(ACD), anterior chamber volume and the anterior chamber angle.<p>RESULTS: The HVID, the thinnest point of the cornea, ACD, and the anterior chamber volume in ROP group were smaller than that in the control group(all <i>P</i><0.05). The CV and the anterior chamber angle in ROP group were smaller than that in the control group, but there was no significant difference between the two groups(all <i>P</i>>0.05). The BCVA was significantly better in the control group than that in the ROP group(0.07±0.10 <i>vs</i> 0.24±0.25, <i>P</i><0.05). <p>CONCLUSION: The development of eye anterior ganglion tissues of the ROP group had changed with steeper cornea, shallower anterior chamber, smaller angle of the anterior chamber and poor BCVA. All of the changes above might make it easier for the development of refractive errors and glaucoma.
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Background Measurement of corneal thickness is of great significance for the design of refractive surgery and the diagnosis of eye diseases,measuring equipments and technology develop rapidly in recent years.Optovue iVue OCT is a new frequency-domain optical coherence tomography (OCT),to compare its results with those of Pentacam and Visante OCT is helpful to objectively assess the clinical value of Optovue iVue OCT.Objective This study was to investigate the repeatability of corneal thickness measurement with Optovue iVue OCT and the comparatbility with Pentacam three-dimensional anterior segment analysis diagnostic system and Visante OCT.In addition,this study attempted to analyze the distribution of average corneal thickness in each quadrant by Optovue iVue OCT.Methods The corneal thicknesses of the corneal thinnest point,the central point and 3:00,6:00,9:00,12:00 zones 1 mm away from the center of the cornea were measured in 45 right eyes of 45 subjects with myopia using Optovue iVue OCT,Pentacam and Visante OCT in Tianjin Eye Hospital.Interclass correlation coefficient (ICC) was used to analyze the repeatability of measurement by Optovue iVue OCT.The agreements between Optovue iVue OCT and Pentacam or Visante OCT were evaluated by Bland-Altman test.The corneal area of 1.0-2.5 mm away from the center was divided into eight quadrants and the average corneal thickness of each quadrant was measured and analysis with Optovue iVue OCT.Results No significant difference was found in corneal thickness values for 3 times by Optovue iVue OCT (P=0.546).The ICC by Optovue iVue OCT was 99.92％,99.99％,99.96％,99.99％,99.99％ and 99.97％ at the corneal thinnest point,the central point and 3:00,6:00,9:00,12:00 zones respectively.There were significant differences among the 3 kinds of methods (P =0.000,0.001,0.000,0.003,0.002,0.000).The measured values of Optovue iVue OCT were significantly lower mean 24.20 μm than those of Pentacam (P=0.000,0.001,0.000,0.003,0.004,0.000),but only the value at 12:00 zone of Optovue iVue OCT was evidently declined in comparison with that of Visante OCT (P =0.016),there were no significant differences between all the other zones (P =1.000,0.447,0.239,1.000,1.000).While the mean corneal thickness value from Pentacam lowed by 14.01 μm in comparison with Visante OCT,all zones had significant differences (P =0.009,0.005,0.034,0.017,0.008) except the central point (P =0.056).Based on the Optovue iVue OCT,the thinnest zone was at temporal quadrant in 23 eyes (accounting for 51.11％) and at superior quadrant or super nasal quadrant in 21 eyes (both at 46.66％).Conclusions Optovue iVue OCT measurement of corneal thickness is of high repeatability and is consistent with Visante OCT in myopic eye.Optovue iVue OCT shows evident difference from Pentacam in the measurement of corneal thickness.The thinnest point of the cornea is mainly in the inferior temporal quadrant and the thickest point is commonly in superior quadrant and nasal superior quadrant based on Optovue iVue OCT.
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Background Keratectasia after laser in situ keratomileusis (LASIK) is one of the serious complications which affect the vision.The measurement of cornea posterior elevation is an important way helping to find this change.Objective The aim of this study was to investigate the change of cornea posterior elevation after LASIK in myopic eyes with astigmatism and affecting factors.Methods A series case-observational study was adopted.One hundred and twenty-seven myopic eyes with astigmatism of 66 patients who received LASIK in 2008 May through 2010 January in Beijing Tongren Hospital were retrospectively analyzed to evaluate the change of cornea posterior elevation following the LASIK.The parameters related to cornea posterior elevation were measured and compared before and 3 months,6 months and 1 year after surgery,respectively,with Oculyzer anterial segment analysis system.Results The height values from posterior cornea highest point,the lowest point and central vertex central elevation zone were (12.20±3.39),(-19.02±7.38) and (1.05 ±3.25) μm respectively before LASIK and were (14.38±3.80),(-18.55±7.11),(2.83±4.81)μm in3 months and (13.99±3.38),(-17.57±6.54),(2.45±4.61) μm in 6 months after LASIK.They were (14.40±3.85),(-17.76±6.00),(2.16±5.00) μm in 1 year after surgery.Significant increases were found in the vertex height and central elevation after LASIK compared with before surgery(highest pointq=6.813,5.594,6.875,all at P＜0.001.central vertex:q=4.488,P=0.002;q =3.530,P=0.013 ;q =2.799,P =0.047).However,no significant difference was seen in various time points after LASIK (P＞0.05).A positive correlation was obtained between the height value of the posterior cornea central vertex with the spherical equivalent (SE),maximum cutting depth or cutting proportion 1 year after LASIK (r =0.295,0.297,0.295,all at P=0.001),and there was a negative correlation between it with residual stroma (r=-0.208,P=0.019).The intraocular pressure (IOP) measured with noncontact tonometry (NCT) was (14.24±3.33) mmHg before LASIK,and those of 3 months,6 months and 1 year were (8.42± 1.90),(8.61 ± 1.64) and (8.76± 1.64)mmHg after LASIK,showing a significant lowing in IOP after LASIK in comparison with before LASIK (q =29.851,28.317,26.337,all at P＜0.001).But no significant change was found in the different time points after LASIK (P＞0.05).There was significant difference in the IOP corrected by Ehlers after LASIK (P＞0.05).The IOP before LASIK had positive correlation with the central elevation of posterior cornea surface 1 year after LASIK(r=0.258,P =0.003).Conclusions The cornea posterior elevation increases slightly early stage after LASIK but retains stable level with lapse of time.The refraction diopter before LASIK is the main factor affecting the posterior corneal shape.To reduce the risk of corneal ectasia,more attention should be paid to the reserving of appropriate corneal residual stroma and smallest degree of eccentricity during the ablation procedure.
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Objective To study the correlations between diopter,axis length,cornea curvature and thickness in myopia patients. Design Prospective case series.Participant 300 myopic patients who were ready for LASIK.Method 300 myopic patients who were ready for LASIK were selected randomly.They were divided into four groups according to the diopter of myopia:low myopia group (≤-3.00D)41 cases,medium myopia group(＞-3.00D,≤-6.00D)130 cases,high myopia group(＞-6.00D,≤-9.00D)95 cases,and super myopia group(＞-9.00D)34 cases.The axis length,cornea thickness,cornea eurvture and diopter of myopia were detected. Through analysis of variance(ANOVA),Pearson correlation analysis and linear regression analysis,the correlations between axis length, cornea thickness,curvature and diopter of myopia were made out in four groups.Main Outcome Measure Diopter of myopia,cornea curvature,axis length of eye and central cornea thickness.Result The axis length of low myopia group,medium myopia group,high myopia group and super myopia group was(24.32?1.73)mm,(25.33?1.49)mm,(26.04?1.92)mm,(27.47?2.57)mm respectively. There were obvious differences of axis lengths between four groups(P=0.000).The cornea curvature in high myopia group was obviously different from those in low myopia group and medium myopia group.There were no significant differences of cornea thickness among four groups(P=0.409).The axis lengths of eyes respectively had correlations with diopters(r=0.734,P=0.000),vertical and horizontal cornea curvatures(r=-0.312,P=0.000;r=-0.328,P=0.000).Conclusion The main effective factor on the diopter of myopia is the axis length for most patients.For the patients with high myopia,the cornea curvature is another effective factor.With the increase of axis length,the cornea curvature decreases,and the cornea turns flatter.(Ophthalmol CHN,2006,15:321-323)
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Objective To investigate the impact factors for temperature of cornea(TOC) and analyse the relationship between TOC and evaporative dry eye. Methods Two hundred and fifty-seven patients(405 eyes) with normal lacrimal secretion received dry eye tests.Patients were divided into positive group and negative group according to the results,and were randomly subdivided into 4 groups with different environment temperature(T) and relative humidity(RH).For all eyes,TOC,body surface temperature(TBS) of forehead and center corneal thickness(CCT) were measured right after blinking.The impact factors for TOC and the differences in TOC between positive group and negative group were analysed.Results TOC was positively correlated with TBS(r=0.89),T(r=0.75) and RH(r=0.60)(P
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N". Except the average (Avg)-RNFLT had positive correlation with diopter in severe myopia group (r=0.372, P=0.047), no significant correlation was observed in other parameters among three groups. Conclusion RNFLT in myopia measured by OCT may have its own rule. Avg-RNFLT may have positive correlation with diopter in severe myopia group.