Central corneal thickness in congenital glaucoma

PURPOSE: The aim of this study was to compare central corneal thickness between eyes with congenital glaucoma and normal fellow eyes in unilateral glaucoma or less affected fellow eyes in bilateral glaucoma. METHODS: Eyes of consecutive phakic children with congenital glaucoma and previous glaucoma surgery were examined under chloral hydrate. Complete ophthalmologic examination, central corneal thickness (CCT), axial length, and corneal diameter measurements were performed. Patients were included in the study if presented with intraocular pressure (IOP) less than 21 mm Hg and no biomicroscopic signs of corneal edema. RESULTS: Nine patients were included in the study. The mean CCT in the more affected eye/glaucomatous eye was 522.3 +/- 65.2 microm and in the less affected eye/healthy eye was 579.7 +/- 44.5 microm. This difference was statistically significant (P = 0.0013). CONCLUSION: CCT was significantly thinner in glaucomatous eyes than in normal fellow eyes in phakic children with congenital glaucoma. This finding may be another confounding factor when measuring IOP in these patients.     

婴儿先天性白内障摘出术后早期中央角膜厚度变化与眼压的相关性研究

目的　测量并观察生后１２个月以内行先天性白内障摘出术患儿术后术眼中央角膜厚度（ｃｅｎｔｒａｌｃｏｒｎｅａｌｔｈｉｃｋｎｅｓｓ,ＣＣＴ）及眼压（ｉｎｔｒａｌｏｃｕｌａｒｐｒｅｓｓｕｒｅ,ＩＯＰ）的变化。方法　选取２６例（４９眼）生后１２个月内行白内障摘出术的先天性白内障患儿为观察组,按行手术时月龄分为三组:１组:月龄≤３个月,２组:３个月＜月龄≤６个月;３组:６个月＜月龄≤１２个月。分别在术前、术后１个月、３个月、６个月时测量术眼ＣＣＴ与ＩＯＰ。另选取与各观察组最后一次随访时的患儿年龄与性别相匹配的相对正常眼婴幼儿作为对照组。结果　观察组术后１个月、３个月、６个月的ＣＣＴ为（５７８．３９±４７．７９）μｍ、（５８１．３４±５１．５４）μｍ、（５８８．２９±４９．９０）μｍ,均显著大于术前（５６３．５６±３７．１４）μｍ及对照组（５３４．９６±４０．３４）μｍ（均为Ｐ＜０．０５）。观察组术前、术后１个月、３个月、６个月ＩＯＰ测量值间差异无统计学意义（Ｐ＞０．０５）,观察组术后６个月ＩＯＰ测量值大于对照组（Ｐ＜０．０５）。观察组术后６个月ＣＣＴ与ＩＯＰ线性相关（ｒ＝０．５３８,Ｐ＝０．００４）。结论　婴儿先天性白内障摘出术后早期的ＣＣＴ显著大于正常同龄婴儿,且与ＩＯＰ线性相关。     

Central corneal thickness in children with congenital glaucoma

PURPOSE: To evaluate central corneal thickness in children with congenital glaucoma. MATERIAL AND METHODS: Central corneal thickness was measured with the use of ultrasound pachymeter in 49 eyes of 30 children, with congenital glaucoma aged 0-12 years. RESULTS: Mean central corneal thickness was 462 microm. Very wide differences between minimum and maximum recorded values were observed (380-780 microm). Three groups of patients could be distinguished: with very thin cornea of 380-450 microm (73% children), with normal corneal thickness of about 550 microm (15%) and with very thick cornea of 680-780 microm (12% patients). CONCLUSIONS: 1. Mean central corneal thickness in children with congenital glaucoma is significantly thinner than in healthy children in the same age and in adult patients with glaucoma. A very wide differences between minimum and maximum recorded values, are observed in these patients. 2. The results of applanation tonometric measurements are underestimated in most cases or less frequently overestimated. 3. The measurements of central corneal thickness should be performed in every patient with congenital glaucoma to correct the IOP values.     

角膜厚度与青光眼危险性的关系

眼压是青光眼主要的致病因素与诊断指标之一，眼压测量值受中央角膜厚度的影响。中央角膜厚度个体差异较大，导致眼压测量值变异较大。中央角膜厚度与原发性开角型青光眼、正常眼压性青光眼及高眼压症患者的眼压之间存在一定的量化关系。角膜越厚，眼压测量值越高。对于正常角膜厚度青光眼患者，眼压受中央角膜厚度的影响不大。高眼压症患者、正常眼压性青光眼患者应常规作角膜厚度测量以排除角膜厚度的影响。中央角膜厚度，眼压与青光眼之间的关系有待于进一步研究。     

角膜中央厚度与高眼压症

目的：探讨部分高眼压症患者所表现出的非病理性高眼压（ＯＨＴ）是否为角膜中央厚度（ＣＣＴ）增加所导致的测量误差。方法：共收集了１１名ＯＨＴ患者（２１只眼）及１１名正常对照。用超声角膜测厚仪测量中央角膜厚度,用角膜曲率测量仪测角膜曲率。结果：ＯＨＴ患者ＣＣＴ为５９４．８±１７．５μｍ,明显高于正常对照（５２９．１±２７．３μｍ）,两组角膜曲率差异无显著性。结论：至少一部分ＯＨＴ患者所表现出的非病理性高眼压来源于增厚的角膜中央厚度造成的测量误差。测量ＣＣＴ对于正确评估压平眼压,判断患者是否存在视野损害的危险及确定治疗与否的临界眼压具有重要临床意义。     

角膜中央厚度与眼压读数

目的　探讨角膜中央厚度与眼压读数的关系。方法　对44例88眼屈光角膜手术前的患者,分别用压平眼压计和超声角膜测厚仪进行角膜中央厚度和眼压的测量,并对二者之间的关系进行统计分析。结果　Ⅰ组角膜中央厚度≥580μm,眼压为21.50～27.00mmHg(23.70mmHg±1.36mmHg)(1kPa=7.5mmHg),屈光度-2.00～-12.00D。Ⅱ组角膜中央厚度＜520μm,眼压为11.00～20.00mmHg(15.66mmHg±1.71mmHg),屈光度-1.25～-11.25D。Ⅰ组眼压高于Ⅱ组（P＜0.001）。结论　角膜厚度与眼压有明显的相关性,即角膜厚度增加眼压相应增高,当眼压读数高于正常时,应考虑到是角膜中央厚度的改变。     

Central corneal thickness in Latinos

PURPOSE: To characterize central corneal thickness (CCT) in Latinos aged 40 or more years. METHODS: A population-based cohort of Latinos from two census tracts in La Puente, California, underwent measurements of CCT and intraocular pressure (IOP). CCT was measured with an ultrasonic pachymeter, and IOP was measured by applanation tonometry. One eye of each of 1699 participants was included in the analyses. RESULTS: The mean (+/-SD) CCT was 546.9 +/- 33.5 micro m. Older participants (>or=70 years) had significantly thinner CCs compared with participants 40 to 49 years of age (P < 0.05). Eyes with ocular hypertension had thicker CCs than did normal and glaucomatous eyes (P < 0.05). Multivariate adaptive regression spline analyses and analysis of variance contrasting IOP subgroups revealed that eyes with thinner CCs had lower IOP than did eyes with thicker CCs (P < 0.001). The absolute range of interocular differences in CCT in the same subject was as high as 24 micro m. CONCLUSIONS: On average, CCT in Latinos was less than that previously reported in whites but greater than that reported in African Americans and Asians. Older Latinos had thinner corneas compared with younger Latinos. Asymmetry in CCT of 25 micro m or more should be evaluated for potential corneal disease. Spline analyses suggest that although the relationship between IOP and CCT is best explained by a nonlinear equation, when measuring IOP with the Goldmann tonometer, it is likely that IOP is underestimated in eyes with thinner CCs and overestimated in eyes with thicker CCs.     

Changes of corneal central thickness of aphakia following congenital cataract surgery under the first six months of life

AIM:To observe the central corneal thickness(CCT) changes in infants and young children who had been undergone bilateral congenital cataract surgery,and to compare the changes with normal control group which was selected from healthy population.METHODS:A cross section case-control study contained 28 cases(56 eyes) of bilateral aphakia(aphakic group) due to congenital cataract surgery combining with posterior continuous curvilinear capsulorhexis and with anterior vitrectomy during 2-6 months after birth.Fourteen children(28 eyes) of age-sex matched with the aphalic group were selected as normal control group.CCT and intraocular pressure(IOP) were measured postoperatively and the results were compared between groups.RESULTS:The mean CCT was 653.5±82.4μm in the aphakic group and 579.6±39.2μm in the control group,with a significant difference(P =0.000).The mean value of IOP in aphakic group(22.0±1.6mmHg) was greater than that of control group(16.9±2.1mmHg),P =0.023.There was a negative correlation between age and CCT in normal control group(r =-0.531,P =0.026),and there was no correlation in bilateral aphakia group(r =-0.324,P =0.165).· CONCLUSION:Aphakic children due to congenital cataract surgery have a greater CCT than normal children.It is necessary to consider CCT in evaluating IOP for children after congenital cataract surgery.     

Central corneal thickness and corneal diameter in premature infants

BACKGROUND: Central corneal thickness is significantly greater in full-term infants than in adults. Very little is known about corneal thickness in premature infants. METHODS: Measurements of central corneal thickness and horizontal corneal diameter were carried out in 35 premature babies (70 eyes) undergoing screening for retinopathy of prematurity. Initial measurements were taken at approximately 31 weeks gestational age and at intervals until term was reached. RESULTS: Babies born at approximately 31 weeks have very thick corneas which show a progressive and statistically significant decrease to term. Conversely, horizontal corneal diameter shows a progressive significant increase to term. A very strong inverse correlation was found between these two parameters. CONCLUSION: We demonstrate that premature infants have thick corneas and small corneal diameters. Central corneal thickness decreases dramatically from approximately 31 weeks to term and is mirrored by a significant increase in corneal diameter.     

Central corneal thickness: z-ring corneal confocal microscopy versus ultrasound pachymetry

PURPOSE: To compare the repeatability and validity of corneal pachymetry by a corneal confocal microscope with a z-axis adapter (Confoscan 4.0 with z-ring adapter: z-CS4) versus ultrasound (US) pachymetry in the measurement of central corneal thickness (CCT). METHODS: CCT in 44 eyes of 44 subjects was determined with z-CS4. Z-CS4 exams were used to estimate the repeatability of thickness measurement by z-ring adapter for this confocal microscope. Intraclass Correlation Coefficient (ICC) between two different z-CS4 users was also determined. CCT in the same 44 eyes was determined with US pachymetry and measurements were compared with z-CS4 CCT. RESULTS: Z-CS4 CCT showed high intrainstrument reproducibility (ICC = 0.989; 95%CI 0.982-0.993; P < 0.0001). Mean difference among three CCT consecutive measures, in the same eye, was 0.8 +/- 11.1 microm. High correlation was found between two users (ICC = 0.896; 95%IC 0.830-0.937; P < 0.0001). Z-CS4 CCT showed high correlation with US pachymetry (ICC = 0.921; 95%CI 0.851-0.958; P < 0.0001). Mean corneal thickness determined was statistically different with the two methods (US: 512.6 +/- 65.8 microm; z-CS4: 487.8 +/- 60.1 microm; P < 0.0001). CONCLUSION: Z-CS4 seems an accurate, noninvasive and reproducible technique for CCT evaluation and confirms that central cornea is thinner when measured with confocal microscopy compared to ultrasounds.     

Central and peripheral corneal thickness in newborns

Central and peripheral corneal thickness was measured in 74 newborn children. The mean central corneal thickness was 0.573 +/- 0.052 mm. The mean peripheral thickness was 0.650 +/- 0.062 mm. There was no significant difference between right and left eyes, sex, gestational age or type of delivery. The central and peripheral corneal thickness in the first 24 h of life was significantly higher than after 48 to 72 h. The full-term babies with 2.500 to 3.000 g of birth weight had peripheral corneal thickness higher than the group with 3.501 to 4.000 g.     

Central corneal thickness and Diaton transpalpebral tonometry

Background To examine the effects of central corneal thickness on the measures obtained from transpalpebral tonometry (Diaton), and to identify correlations between intraocular pressure (IOP) measurements with Diaton and the Goldmann applanation tonometer (GAT). Methods In this cross-sectional study, 162 eyes of 81 participants were included. Intraocular pressure measurements were obtained in all patients using Diaton and GAT. Central corneal thickness was determined by ultrasound pachymetry. The participants were stratified by corneal thickness: group I <530 μm (n = 56), group II 530–560 μm (n = 65), and group III >560 μm (n = 41). Results There were moderate correlations between IOP readings obtained using the Diaton and corrected GAT (C-GAT) (r = 0.303; P < 0.0001), and between corrected Diaton (C-Diaton), and C-GAT (r = 0.399; P < 0.0001). The mean Diaton tonometer readings were lower than C-GAT measurements (Diaton-corrected GAT mean difference, 0.9 ± 3.8 mmHg; c-Diaton-corrected GAT mean difference, 0.7 ± 3.5 mmHg). Differences were detected between the groups of patients for the GAT values [2.4 ± 3.6 mmHg for those with the thinnest corneas (<530 μm), 0.7 ± 3.6 mmHg for those with moderate corneas (between 531 μm and 560 μm), and −0.6 ± 3.6 mmHg for those with the thickest (>560 μm) corneas], whereas a significantly lower difference (0.9 ± 3.8 mmHg) was noted for the Diaton values of all individuals. Conclusions The Diaton measurements show moderate correlation with those provided by applanation tonometry. The Diaton tonometer seems to be more affected by the corneal thickness, especially in the thinnest corneas. No author has a financial interest in any product mentioned in the article. No author has a conflict of interest in any product mentioned in the article.