Central corneal thickness and intraocular pressure in premature infants

The Effect of an Eyelid Speculum on Intraocular Pressure Measurement in Newborns

PURPOSE

To evaluate the effect of an eyelid speculum on intraocular pressure (IOP) measurements in newborns.

METHODS

A total of 54 eyes of 27 newborns were involved in the study. The IOP measurements were obtained under topical anesthesia with the Icare PRO (Icare Finland Oy) before and after inserting the infant type of Barraquer wire eyelid speculum. A paired t test was used to compare the measurements.

RESULTS

The mean IOP without the eyelid speculum was 9.04 ± 2.13 mm Hg (range: 6.00 to 13.20 mm Hg) in the right eye and 9.26 ± 1.59 mm Hg (range: 7.10 to 13.00 mm Hg) in the left eye. With the eyelid speculum in place, the mean IOP was 11.91 ± 2.23 mm Hg (range: 9.10 to 15.80 mm Hg) in the right eye and 11.70 ± 1.89 mm Hg (range: 8.40 to 14.50 mm Hg) in the left eye (P ≤ .001). The mean differences in IOP between measurements with and without the eyelid speculum were 2.87 ± 2.23 mm Hg (range: 0.20 to 5.20 mm Hg) in the right eye and 2.44 ± 1.48 mm Hg (range: 0.00 to 4.90 mm Hg) in the left eye. The mean difference in IOP between measurements with and without the eyelid speculum for all eyes was 2.65 ± 1.89 mm Hg (range: 0.00 to 5.20 mm Hg). There was no correlation between the difference in IOP after the placement of the eyelid speculum and postconceptual age or weight at the examination (r = 0.11, P = .41, r = 0.32, P = .14, respectively).

CONCLUSIONS

The Barraquer wire eyelid speculum caused an increase in IOP in newborns under topical anesthesia without a significant difference between postconceptual age and sex in both eyes. The average IOP rise after the eyelid speculum was inserted was 2.65 mm Hg. This effect should be considered when interpreting IOP measurements in newborns. [J Pediatr Ophthalmol Strabismus. 2022;59(1):13-16.].

Correlation of central corneal thickness and associated factors in premature infants with and without retinopathy of prematurity

OBJECTIVE

Central corneal thickness (CCT) in premature infants is described in racially homogenous populations, and factors affecting CCT in infants are relatively unknown. This study describes CCT in premature infants and its association of steroid and oxygen requirements, gestational age (GA), birth weight (BW), race, and their relationship with CCT and corneal haze.

METHODS

CCT measurements of 87 infants/174 eyes screened for retinopathy of prematurity were taken between 30 and 44 weeks of GA. CCT was analyzed using a mixed model for its relationship with BW, GA, race, corneal clarity, steroid, and oxygen use.

RESULTS

Average CCT decreased at a rate of 12.3 μm/week. Caucasians had the thickest corneas and Hispanics the thinnest (p < 0.01) at baseline, but the rate of CCT decline varied based on racial/ethnic group (p = 0.079). Infants with BW <1000 g had a higher CCT at baseline, but CCT decreased at a faster rate than infants with higher BW (-13. 4 μm/week vs -9.9 μm/week, p = 0.020). Infants born <27 weeks of GA had higher CCT at baseline, but CCT decreased at faster rate compared with patients born later (-13.3 μm/week vs -10.1 μm/week, p = 0.029). Steroid and oxygen use were not statistically significantly associated with CCT or corneal haze (p > 0.05) CONCLUSIONS: CCT varies by racial group in premature infants. Lower BW and GA are associated with increased CCT at baseline but thin at a faster rate. Average, CCT decreases at a rate of 12.3 μm/week between 30 and 44 weeks GA and averages to 550 μm by 44 weeks GA.

Central corneal thickness changes and horizontal corneal diameter in premature infants: A prospective analysis

To report observations of horizontal corneal diameter (HCD) and central corneal thickness (CCT) changes in premature infants with stable optic disc cupping and intraocular pressures (IOPs). The HCD and CCT at term serve as a baseline for premature infants.Sixty-three premature infants were enrolled in a prospective case series. HCD, CCT, and IOP were measured. RetCam images of the optic discs were used to evaluate the cup-disc ratio (CDR) and read by an independent masked observer. Data were collected at between preterm (32-36 weeks) and again at term (37-41 weeks) postconceptual age. Left eye measurements were used for statistical analysis. Left eye findings were combined to construct predictive models for HCD and CCT.The mean HCD was 9.1 mm (standard deviation [SD] = 0.7 mm) at preterm and 10.0 mm (SD = 0.52 mm) at term. The mean CCT preterm was 618.8 (SD = 72.9) μm and at term 563.9 (SD = 50.7) μm, respectively. The average preterm CDR was 0.31 and at maturity was 0.33. Average IOP of preterm and term was 13.1 and 14.11 mm Hg, respectively. There was significant linear correlation between HCD with the postmenstrual age (r = 0.40, P < .01) and the head circumference (r = 0.33, P < .05). Predictive models were constructed for HCD (R = 0.52, 0.2 mm/wk) and CCT (R = 0.23, -11.4 μm/wk) with postconceptual ages.The HCD and CCT variation did not affect IOP reading over time. CCT was not correlated with birth parameters and decreased as the infant reached term. Corneal diameter correlated with gestational age at birth and head circumference.

Preoperative biometry data of eyes with unilateral congenital cataract

PURPOSE

To investigate the differences in biometry data of eyes with unilateral congenital cataract and the contralateral normal eyes in pediatric patients.

SETTING

Pediatric Ophthalmology Division, Ophthalmology Department, Semmelweis University in Budapest, Hungary.

DESIGN

Retrospective case series.

METHODS

Data of visually significant unilateral congenital cataract patients who had cataract surgery in the ophthalmology department at Semmelweis University between 2013 and 2016 were collected. At the time of the examinations, the mean age of the patients was 36.4 weeks ± 25.3 (SD). Central corneal thickness (CCT), corneal refractive power (keratometry [K]), horizontal corneal diameter, and axial length (AL) measurement data were obtained from both eyes of each patient. The measurements were taken under general anesthesia using a handheld kerato-refractometer (Retinomax K-plus 3) and an ultrasound instrument (Ocuscan RxP) with contact applanation method and Castroviejo straight-tip calipers at the beginning of the cataract surgery. For statistical evaluation, Originlab 7.0 software was used; paired t tests were performed for the difference analysis between the 2 sides.

RESULTS

Forty-two infants (50% girls) were included. In the cases of eyes with unilateral congenital cataract, a greater CCT (P = .01330), higher average K (P = .00243), and smaller corneal diameter (P = .00010) were found, although there was no significant difference in AL when compared with the unaffected contralateral eyes.

CONCLUSION

The data showed that biometric characteristics of the eyes with unilateral congenital cataract differ from the opposite normal eye before the cataract surgery. It is essential to use this biometric data in intraocular lens power calculation and to take them into account in long-term care when screening for secondary glaucoma.

Distribution of corneal thickness and its determinants in 6-12-year-old children in an Iranian general population

Purpose

To determine the central corneal thickness (CCT), apex, and paracentral thicknesses and their determinants in children aged 6-12 years.

Methods

The present study was part of the phase 1 of Shahroud School Children Eye Cohort Study in 2015. Cluster sampling was done in urban areas while all children were invited to participate in the study in rural areas. The Pentacam HR was used for measurements. CCT was measured within the central 3 mm zone of the cornea, and corneal thickness 3 mm further from the center was considered paracentral thickness.

Results

Of 6624 students who were selected, 5620 (84.8%) participated in the study. Among 4956 students, studied in this report, 52.2% were boys, and the mean age of the study participants was 9.75 ± 1.71 years (6-12). The mean CCT and apical thickness was 556.29 ± 34.04 and 557.43 ± 34.03 μm, respectively. The mean paracentral thickness was 657.62 ± 39.11 μm in the superior, 632.65 ± 37.63 μm in the inferior, 648.64 ± 38.75 μm in the nasal, and 617.36 ± 37.19 μm in the temporal region. A multiple regression model showed that CCT decreased by 4.70 μm with every 1 diopter increase in the mean keratometry and increased by 20.06 μm with every 1 mm increase in the anterior chamber depth (ACD) (Both P-Value < 0.001). Age, sex, ethnicity and residence place were also found to be associated with CCT.

Conclusions

This study is the first to describe the distribution of corneal thickness in Iranian children with a large sample size. This study showed that corneal thickness was significantly correlated with younger age, female gender, urban residence, and a number of biometric variables.

Pre- and Postnatal Development of the Eye: A Species Comparison

In this review paper, literature data on pre- and postnatal eye development are compared between humans and nonclinical species that are commonly used for human safety assessment, namely, mouse, rat, rabbit, dog, minipig, and nonhuman primates. Some new data on rat and minipig ocular development are also included. This compiled information can be helpful for species selection in juvenile toxicity studies or assist in the interpretation of (non)clinical data during pediatric drug development. Despite some differences in developmental windows and anatomical peculiarities, such as the lack of a fovea centralis in nonprimate species or the presence of a nictitating membrane in some nonclinical species, the functioning and development of the eye is strikingly similar between humans and other mammals. As such, all commonly used nonclinical species appear to be relatively good models for human eye development, although some practical constraints such as size may be a limiting factor. Birth Defects Research 109:1540-1567, 2017. © 2017 Wiley Periodicals, Inc.