Central corneal thickness measurements in premature infants

AIM:To evaluate the central corneal thickness (CCT) measurements of premature infantsMETHODS: The premature infants who were born between 25-34wk of gestational age (GA) were retrieved for the study. All CCT measurements were performed within the first 2d of their life under topical anesthesia by using an ultrasonic pachymeter.RESULTS: The mean CCT of 200 eyes was 647.79±63.94 μm. The mean CCT of the right and left eyes were similar (647.30±64.72 μm and 648.29±63.47 μm consecutively). The mean CCT of the girls was 642.08±54.89 μm and the boys was 653.07±71.14 μm, with no statistically significant difference (P>0.05). But there was a negative correlation of the CCT with GA and birth weight (BW) (P<0.01).CONCLUSION:The CCT values of premature babies were negatively correlated with GA and BW.     

Central corneal thickness in premature babies

Central corneal thickness was measured in 13 premature babies with a gestational age below 33 weeks. No difference was found between the thickness in the first and third post-natal week. At the age of 3 months the thickness had decreased significantly to the same level previously reported in full-term newborns. There was no correlation between gestational age, birth length and weight and central corneal thickness.     

Central corneal thickness and corneal diameter in patients with childhood glaucoma

PURPOSE: To determine and compare the central corneal thickness (CCT) and corneal diameter among groups of patients with childhood glaucomas and assess the relationship between CCT and corneal diameter in these patients. DESIGN: A multicenter observational case series using prospective and retrospective data. METHODS: Patients from the Scheie Eye Institute, Children's Hospital of Philadelphia, and Emory and Vanderbilt Medical Centers with childhood glaucomas were eligible to participate. Retrospective data on CCT and corneal diameter of these patients were collected when available; otherwise, patients were asked to return to the ophthalmology clinics for measurements. Patients with corneal edema or central corneal scarring were excluded. One hundred eighty four glaucomatous eyes from 109 patients (median age = 9.0 y; age range = 0 to 60 y) were included. RESULTS: The mean CCT (+/-SE) was 651.1+/-63.5 microm for aphakic, 528.7+/-38.5 microm for Axenfeld-Rieger, and 563.4+/-67.9 microm for 1 degrees infantile eyes. The mean corneal diameter in aphakic, Axenfeld-Rieger, and 1 degrees infantile glaucoma eyes were 11.2+/-1.0, 12.5+/-0.9, and 13.2+/-1.2 mm, respectively. There was a significant difference in CCT and in corneal diameter between aphakic and 1 degrees infantile glaucoma eyes, and between aphakic and Axenfeld-Rieger eyes (P < 0.0001). There was a negative correlation between CCT and corneal diameter in all eyes (r = -0.41, P < 0.0001). CONCLUSIONS: Patients with aphakic glaucoma are different from those with congenital glaucoma or Axenfeld-Rieger in CCT and corneal diameter. A patient with pediatric glaucoma and a larger corneal diameter was more likely to have a thinner CCT. Attention should be paid to the CCT of patients with childhood glaucomas for interpretation of intraocular pressure.     

Corneal diameter in premature infants.

The size of the cornea is important in the diagnosis of primary infantile glaucoma. Reference values regarding eyes of premature infants are scarce. Such data are of special importance in areas such as the Middle East where infantile glaucoma is common and often evident already at birth. The authors have measured the horizontal corneal diameter of the eyes of 127 premature Saudi infants with a gestational age between 23 and 36 weeks and a birth weight ranging from 540 g to 4720 g. The corneal diameter ranged from 7.75 mm to 10 mm. The smallest diameter (7.75 mm) was found in an infant with a gestational age of 23 weeks and having a birth weight of 520 g. The largest diameter (10 mm) belonged to two infants with a gestational age of 34 and 35 weeks and a birth weight of 2250 g and 2240 g respectively. Corneal diameter was positively correlated (p < 0.001) with gestational age and birth weight. Graphs depicting the regression line of corneal diameter on gestational age and of corneal diameter on birth weight together with the 95% confidence limits for individual values are provided for reference.     

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。     

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.     

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 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.     

Central corneal thickness in full-term newborns

The central corneal thickness (CCT) was measured in 30 full-term newborns in the first week post partum using ultrasonic pachometry. The mean CCT in the right eyes was 0.581 +/- 0.047 mm. In 19 babies the CCT was measured twice. The mean CCT in the second reading was 0.584 +/- 0.042 mm. This difference was not statistically significant. There was no correlation between gestational age, birth weight and length, and CCT. The small difference between girls and boys was not statistically significant. The values in the left eyes were similar to the data for the right eyes. These results confirm the results in the only previous study on CCT in newborns, that is, that CCT is significantly larger than the CCT in adults.     

Central corneal thickness in Japanese children

Purpose  To determine the central corneal thickness (CCT) in Japanese children and to investigate the changes in CCT with increasing age. Methods  Pachymetry was performed on 338 eyes of 169 patients undergoing eye muscle surgery under general anesthesia, and the intraocular pressure (IOP) was measured on 312 eyes of 156 of those same patients. Patients with abnormalities other than refractive errors and strabismus were excluded. Patients were divided into four groups: group 1, ≤1 year of age; group 2, 2–4; group 3, 5–9; and group 4, 10–18 years of age. Analysis of variance (ANOVA) was performed to determine the significance of the changes in CCT. Results  The average CCT of the right eye was 544.3 ± 36.9 μm. The CCT was thinner in group 1 than in groups 3 and 4 (ANOVA, P = 0.02). There was a positive but weak correlation between IOP and CCT (IOP = 6.253 + 0.014 × CCT; r ² = 0.047, P = 0.007). Conclusions  CCT reaches the adult thickness in Japanese children by age 5 years. The average CCT is thinner in Japanese children than in Caucasians but thicker than in African American children.     

Central corneal thickness in high myopia

PURPOSE: To examine if central corneal thickness (CCT) is different in emmetropia and high myopia. METHODS: 57 emmetropic subjects (0 to + 1.5 D) and 48 high myopes (all more than - 6 D in spherical equivalent refraction) were studied. CCT was measured by a Haag-Streit Optical Low-Coherence Reflectometry (OLCR) pachymeter, a recently developed high precision pachymeter with a standard deviation (SD) for repeated measurements of 1 microm. RESULTS: Mean CCT for the emmetropic group was 538.6 microm (SD = 32.1), and for the myopic group 527.7 microm (SD = 35.0). Neither the mean CCT nor the variance from the two groups showed a statistically significant different (p > 0.05). CONCLUSION: CCT is not systematically altered in myopia. The process by which the myopia progresses does not to a measurable degree influence the central cornea.     

Central corneal thickness measurements in children

PURPOSE: To evaluate central corneal thickness in children. MATERIAL AND METHODS: Central corneal thickness was measured with the use of ultrasound pachymeter in 360 children aged 0-14 years. RESULTS: Mean central corneal thickness was 537 microm after the birth and 567 microm in the age of 14 years. Wide differences between minimum and maximum recorded values were observed (410-650 microm) in first 2 years of life, and 420-640 microm in years 2-14. CONCLUSIONS: 1. Mean central corneal thickness in children (even in small one's) does not differ significantly from adults and does not change with age. 2. Great differences between minimum and maximum recorded values were observed in children (especially in first two years of life), exceeding the range in adults. 3. IOP measurements in children should be corrected according to the results of central corneal thickness.     

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。