Mean Horizontal Corneal Diameter Research Articles

CYP1B1 and MYOC Gene Analysis of Patients with Primary Congenital Glaucoma in the Cukurova Region of Turkey

AbstractThe aim of this study was to investigate the CYP1B1 and MYOC genes in patients with primary congenital glaucoma (PCG) from the Cukurova region (located in the south of Türkiye) and reveal the relationship between gene mutations and clinical severity of the disease. Molecular genetic and clinical study was conducted in 42 eyes of 26 patients who were followed for a diagnosis of PCG. The clinical diagnosis was concluded by ophthalmological examination under general anesthesia or slit-lamp biomicroscopy, gonioscopy, and measurement of the intraocular pressure. A CYP1B1 gene mutation was detected in 12 patients (46.2%). Two of these patients had a combination of CYP1B1 and MYOC mutations. The most common pathogenic variant, c.1405C > T (p.R469W) (n = 5), was present in patients with mutations, and the prognosis was poor compared with other modifications (p = 0.014). The second most common variant was c.3987G > A (p.G61E) (n = 3), which was associated with a good prognosis. The incidence of buphthalmos and the mean horizontal corneal diameter were higher in patients with mutations in the CYP1B1 and MYOC genes. All parents were found to be carriers of the mutation gene. This is the report on molecular genetic analysis of PCG in the southern region of Türkiye. Some specific genetic variants may have an effect on the prognosis of the disease. However, patients without mutations in these case groups may have mutations in genes yet to be identified.

Outcomes of surgical treatment of congenital cataract with microphthalmia in infancy

Objective: To examine the outcomes of surgical treatment for infants with congenital cataract and microphthalmia (CATM). Methods: It was a retrospective case series study. Data of 28 (55 eyes) CATM children who underwent cataract surgery at the Qingdao Eye Hospital of Shandong First Medical University and were followed up for more than 5 years between January 2010 and December 2014 under the age of 6 months. There were 15 male and 13 female children. The age at the time of surgery was (3.2±1.3) months, and the follow-up time was (8.2±1.7) years. The data included the basic information of the children, the ocular biological parameters before and after surgery and intraocular lens (IOL) implantation, and the occurrence of complications. Paired t-tests or Wilcoxon signed rank tests were used to compare groups, and logistic regression analysis was used to identify factors related to IOL implantation, secondary glaucoma, and visual axis opacification (VAO). Results: The mean preoperative axial length was (16.6±1.0) mm, and the mean horizontal corneal diameter was (9.5±0.9) mm. The axial growth rate within 2 years after the first stage of surgery was (1.4±0.8) mm/year. None of the children had an IOL implanted before the age of 2. Sixty percent of the eyes (33/55) received IOL implantation within 2 to 4 years after the first stage of surgery, while the remaining 40% (22/55) did not receive IOL implantation at the last follow-up. The axial growth rate was (0.9±0.7) mm/year within two years after the second stage of surgery. Postoperative secondary glaucoma occurred in 7 eyes (12.7%), and VAO occurred in 15 eyes (27.3%). IOL implantation was associated with preoperative axial length (OR=0.072, P<0.001) and age at the first stage of surgery (OR=7.270, P<0.001), but not with preoperative corneal diameter (P=0.735). The incidence of VAO was associated with preoperative corneal diameter (OR=4.124, P=0.011), but not with age at the first stage of surgery (P=0.489) or preoperative axial length (P=0.489). No factors related to the occurrence of secondary glaucoma were found. The best corrected visual acuity at the last follow-up after IOL implantation was (0.37±0.28) logMAR, which was better than that of children without IOL implantation (0.67±0.19) logMAR (U=49.50, P=0.003). Conclusions: Children with CATM can obtain the opportunity for IOL implantation through early surgery and ultimately achieve good visual outcomes. Properly selecting the timing for implanting IOL can keep the incidence of secondary glaucoma at an acceptable level.

Profile of primary childhood glaucoma at a child eye health tertiary facility in Malawi

BackgroundTo describe the clinical characteristics and treatment of primary childhood glaucoma at Queen Elizabeth Central Hospital in Blantyre, Malawi.MethodsA retrospective case notes review was undertaken of all medical records of patients aged less than 16 years with a diagnosis of primary glaucoma according to the Childhood Glaucoma Research Network Classification (CGRN) who presented from January 2016 to December 2018. The parameters extracted from the case files included age at presentation, sex, type of glaucoma, presenting complaints, laterality of ocular involvement, examination findings and the treatment modality instituted. The Mann-Whitney test was used to investigate factors associated with the intraocular pressure (IOP) in eyes that had a higher presenting IOP value compared to contralateral eyes.ResultsA total of 45 subjects (80 eyes) were identified, 42 with primary congenital glaucoma (PCG) and 3 with juvenile open angle glaucoma (JOAG). The mean age for the population was 2.6 years (S.D ± 3.7) and most of the patients were male, with a male-female ratio of 2:1. The majority of patients had bilateral disease (n = 35, 77.8%) with the commonest presenting complaint being a whitish appearance of the eye (57.5%). The eyes studied had a mean IOP of 30.1 mmHg (CI 27.4–32.9), a mean horizontal corneal diameter (HCD) of 13.6 mm (CI 13.1–14.2) and a mean cup-disc-ratio `(CDR) of 0.73 (CI 0.66–0.79). In addition, 62 eyes (77.5%) had corneal haze on examination. Most patients (n = 59, 73.8%) underwent a combined trabeculotomy – trabeculectomy surgery within the study period. The median presenting IOP was significantly higher with JOAG compared to PCG (P = 0.02).ConclusionPCG was the most common primary childhood glaucoma at Queen Elizabeth Central Hospital and most patients presented with bilateral eye involvement. Most of the eyes had corneal haze and JOAG was associated with a higher presenting IOP compared to PCG. Further studies to investigate the outcomes of combined trabeculotomy – trabeculectomy surgery in primary childhood glaucoma in Malawi are recommended.

Corneal Biometric Parameters and Refractive Properties in Microcornea With Normal Axial Length.

The purpose of this study was to evaluate the features of and relationships among corneal diameter, central corneal thickness (CCT), endothelial cell density (ECD), and corneal refractive properties in cases of microcornea (MC) with normal axial length. We included 22 patients (35 eyes) with MC and cataracts and 41 patients (48 eyes) with isolated cataracts as age-matched controls. They were divided into patients with MC younger than 18 years (MC-child), patients with MC 18 years or older (MC-adult), children with congenital cataracts (CCs), and adults with senile cataracts (SCs). Corneal diameter, axial and anterior chamber length, and keratometry were measured; central corneal endothelial cell imaging was performed. The mean horizontal corneal diameter was 7.71 ± 1.51 and 8.78 ± 0.52 mm in MC-child and MC-adult groups, respectively, and 11.89 ± 0.59 and 11.52 ± 2.42 mm in child and adult controls, respectively. The mean CCT was 641.26 ± 63.37 (MC-child) and 617.38 ± 45.40 mm (MC-adult), and 554.92 ± 34.64 (CC) and 551.58 ± 28.47 mm (SC). The mean ECD was 2898.47 ± 443.90 (MC-child) and 2825.81 ± 484.65 cells/mm 2 (MC-adult), and 3155.13 ± 372.67 (CC) and 2749.33 ± 399.63 cells/mm 2 (SC). The average keratometry was 44.22 ± 3.14 D (MC-child) and 43.86 ± 2.59 D (MC-adult), and 44.19 ± 1.44 D (CC) and 43.94 ± 1.34 D (SC). Patients with MC and normal axial length possess specific parameters, including significantly smaller corneal diameter and thicker CCT than the patients in the control groups. There were no significant differences in ECD and average keratometry. These parameters should be taken into account in the follow-up and treatment.

Evaluation of the Relationship between Corneal Diameter and Lens Diameter in Children

Primary intraocular lens (IOL) implantation has gained acceptance for management of infantile cataracts because of the advantage of reduced amblyopia risk. The aim of the study was to investigate the association between corneal diameter as measured from the white-to-white distance and natural lens diameter in children. This association may aid intraocular lens selection following cataract removal in infants and young children. A cross-sectional study was performed on forty eyes from 40 children less than 4 years, who needed to be examined, were planned for a procedure or operation under general anaesthesia. Subjects were recruited from Eye Clinic,Kuala Lumpur General Hospital from January 2010 to September 2011. Corneal diameter was measured with Holladay-Godwin corneal gauge while lens diameter was measured with ultrasound biomicroscope (UBM) during surgery. For the results, mean age of subjects was 24.7 + 12.1 months. Mean corneal diameter was 11.62 + 0.50 mm horizontally and 11.20 + 0.58 mm vertically. Mean horizontal lens diameter was 7.94 + 0.47 mm. A medium positive correlation was found between mean horizontal corneal diameter and lens diameter (r=0.479, p=0.002). Lens diameter had a strong correlation with patient’s age (r=0.718, p&lt;0.001). Lens diameter can be calculated by using this model of equation: [Lens diameter (mm) = 7.010 + 0.021 Corneal Diameter (mm) + 0.028 Age (months)] (r2=0.52). In conclusion, there was a moderate positive correlation between corneal and lens diameter. UBM can be used to measure lens capsular bag size directly preoperatively.

Ophthalmic examination, biometry, and histologic findings in captive inland bearded dragons (Pogona vitticeps).

To report ophthalmic examination, biometry, phenol red thread test (PRTT), intraocular pressure (IOP), and histologic findings from a private collection of inland bearded dragons (Pogona vitticeps). Fourteen inland bearded dragons. Complete ophthalmic examinations were performed on all animals, including slit-lamp biomicroscopy, indirect ophthalmoscopy, fluorescein stain, phenol red thread test, and rebound tonometry. B-mode ultrasonography was used to measure anterior chamber depth, axial lens thickness, vitreal chamber depth, and axial globe length. Horizontal corneal diameter was estimated using ImageJ software. Histologic assessment was obtained for one of the bearded dragons that died following the study period. The median PRTT value was 7.27mm/15seconds. Mean IOP was 6.29±1.60mmHg and 2.14±1.37mmHg using the dog and undefined calibration settings, respectively. Median axial globe length was 11.75mm. Mean anterior chamber depth and mean lens thickness were 2.06±0.35mm and 3.38±0.45mm, respectively. Median vitreal chamber depth was 6.79mm. Mean horizontal corneal diameter was 5.138±0.346mm. Two distinct ocular phenotypes were observed, with two of the bearded dragons having corneal globosa, deep anterior chambers, and tufts of iridal vessels and fibrillar material extending into the anterior chamber. The ultrasound biometry, PRTT, and rebound tonometry results may serve as a guideline for ophthalmic parameters in healthy bearded dragons. Examination and testing of greater numbers of animals are necessary to establish true reference ranges and determine if the observed ocular phenotypes represent normal variants or pathologic changes.

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 (R2 = 0.52, 0.2 mm/wk) and CCT (R2 = 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.

Implantation of glued intraocular lenses in eyes with microcornea

To evaluate the intraoperative modifications for and vision outcomes after implantation of glued intraocular lenses (IOLs) in eyes with microcornea. Dr. Agarwal's Eye Hospital and Eye Research Centre, Chennai, India. Prospective case series. Eyes with a horizontal cornea of 10.0 mm or less were evaluated for intraoperative modifications and postoperative vision after implantation of a glued IOL. The type of surgery, type of IOL, incision and optic sizes, haptic length modifications, uncorrected (UDVA) and corrected (CDVA) distance visual acuity, and postoperative complications were analyzed. A glued IOL was implanted in 15 eyes to treat subluxated cataract (9 eyes), aphakia (5), and intraoperative capsule loss (1). In cases involving a subluxated cataract, implantation of the glued IOL was followed by lensectomy (7 eyes) or intracapsular cataract extraction (2 eyes). The mean follow-up was 22.4 months ± 17.2 (SD). The mean horizontal corneal diameter and axial length were 8.0 ± 0.6 mm and 21.0 ± 2.4 mm, respectively. The mean amount of IOL haptic trimmed intraoperatively was 1.54 ± 0.33 mm. There was significant correlation between the horizontal corneal diameter and the amount of haptic trimmed (P = .000). The mean size of the main incision was 3.70 ± 0.98 mm. Three-piece foldable IOLs with a 6.0 mm optic were used. There were no cases of haptic extrusion or subconjunctival haptic placement. There was statistically significant improvement in CDVA (P = .032) and UDVA (P = .012) after surgery. Glued IOLs were safely implanted in eyes with microcornea using modifications such as custom haptic trimming and 6.0 mm optic foldable IOLs. Dr. Amar Agarwal is a paid consultant to Staar Surgical Co. No other author has a financial or proprietary interest in any material or method mentioned.

Combined trabeculotomy and trabeculectomy: outcome for primary congenital glaucoma in a West African population

To evaluate the surgical outcome of combined trabeculotomy-trabeculectomy in Ghanaian children with primary congenital glaucoma. A retrospective case series involving 19 eyes of 12 consecutive children with primary congenital glaucoma who had primary trabeculotomy-trabeculectomy from 12 August 2004 to 30 June 2008, at the Korle-Bu Teaching Hospital, Ghana. Main outcome measures were preoperative and postoperative intraocular pressures, corneal diameter, corneal clarity, bleb characteristics, duration of follow-up, surgical success, and complications. A total of 19 eyes of 12 patients met the inclusion criteria. Six of the patients were males. Mean age at diagnosis was 4.4 (range 2-8) months. Mean age at surgery was 5.9 months (range 3-16). Eight (67%) infants had bilateral disease. Mean duration of follow-up was 13.1 (range 5-38) months. The preoperative mean horizontal corneal diameter was 13.4 ± 1.1(range 12-16) mm. Complete success (intraocular pressure <21 mm Hg) was obtained in 15 (79%) eyes. The probability of success was 94.4, 83.3, 66.7, 44.4, 38.9, 33.3, and 13.3% at 3, 6, 9, 12, 15, 18, and 21 months, respectively (Kaplan-Meier analysis). All eyes had corneal oedema preoperatively. Seventeen eyes (90%) had clear cornea at their last follow-up. Mean preoperative and postoperative intraocular pressures were 30.3 ± 8.8 and 18.1 ± 6.8 mm Hg respectively (P<0.001, t-test). Twelve (63%) eyes had well-functioning blebs at the last follow-up. One eye (5%) developed seclusio pupillae and cataract postoperatively. The overall success for combined trabeculotomy-trabeculectomy in Ghanaian children with primary congenital glaucoma was 79%. The probability of success reduced from more than 66% in the first 9 months postoperatively to below 45% after that.

Comparison of Eyemetrics and Orbscan automated method to determine horizontal corneal diameter

Purpose:To compare horizontal corneal diameter measurements using the Orbscan Eyemetrics function and Orbscan corneal topographer.Materials and Methods:Seventy-three eyes of 37 patients were included in the study. In all cases, the automated white-to-white (WTW) measurements were obtained using Orbscan by two observers. Using the Eyemetrics function, the WTW was measured manually by the same observers from limbus to limbus using the digital caliper passing through the five point corneal reflections on the Orbscan real image. The data was analyzed using SPSS software for correlation, reliability and inter-rater repeatability.Results:The mean horizontal corneal diameter was 11.74 ± 0.32mm (SD) with the Orbscan and 11.92 ± 0.33mm (SD) with Eyemetrics Software-based measurement. A good positive correlation (Spearman r = 0.720, P = 0.026) was found between these two measurements. The coefficient of inter-rater repeatability was 0.89 for the Orbscan and 0.94 for the Eyemetrics software measurements on the anterior segment images. The Bland and Altman analysis showed large limits of agreement between Orbscan WTW and Eyemetrics WTW measurements. The intra-session repeatability scores for repeat measurements for the Orbscan WTW and Eyemetrics measurements were good.Conclusion:Eyemetrics can be used to measure WTW and the Eyemetrics measured WTW was longer than the WTW measured by Orbscan.

Comparison of horizontal corneal diameter measurements using Galilei, EyeSys and Orbscan II systems

Background: White‐to‐white corneal measurement is used frequently in cataract and refractive surgery as well as in diagnosing various corneal diseases and monitoring congenital glaucoma. In this article, we determine agreement in horizontal corneal diameter measurements in normal eyes among the Galilei V4.01, the EyeSys and the Orbscan IIz.Methods: In this prospective study, 37 consecutive volunteers were enrolled. All 74 eyes were measured with all three devices. Galilei, EyeSys and Orbscan II measurements were compared with one another. In addition, the data from the right and left eyes were compared for each device.Results: The mean horizontal corneal diameter measurements with the Galilei, the EyeSys and the Orbscan II were 12.01 ± 0.61-mm, 12.09 ± 0.87-mm and 11.67 ± 0.29-mm, respectively. The difference between the Galilei and EyeSys systems was not statistically significant (p = 0.76), however, the Orbscan II showed smaller measurements (p < 0.001). The best 95% limits of agreement between devices were for the Galilei and the Orbscan II (‐0.72, 1.48; r = 0.4, p < 0.01). The best 95% limits of agreement between two eyes for each device were found with the Orbscan II (‐0.15, 0.17; r = 0.996, p < 0.01). There was no correlation between measurements of right and left eyes for the Galilei or the EyeSys (r = 0.274, p = 0.176 and r = 0.31, p = 0.065, respectively).Conclusions: These results suggest that measurements made with the Orbscan II are smaller than those obtained with the EyeSys Corneal Analysis system and the Galilei. Among the three devices, the Galilei and the Orbscan II showed the best agreement, however, it is inadvisable to use the three devices interchangeably in every clinical situation.

Anterior segment biometrics – investigation of hyperopic eyes with Orbscan

Abstract Purpose Assessment of the anterior segment by Orbscan in hyperopic eyes. Methods 30 normal right eyes (10 younger hyperopes, 10 older hyperopes, 10 younger emmetropes) were assessed with Orbscan II. Anterior chamber depth (ACD), horizontal corneal diameter (HCD), anterior (AK) and posterior corneal radius (PK), central (CCT) and peripheral corneal thickness (PCT, 4mm from centre) were analysed in the younger (≤ 45 years of age) and older hyperopic subjects (&gt; 45 years). The data from the younger hyperopic group were also compared with the age‐matched emmetropic subjects. Results All data were normally distributed (p ≥ 0.403). For the 20 hyperopic subjects, the mean refractive error was +2.33 D (SD+/‐ 1.85 D), the mean ACD was 2.59 +/‐ 0.35 mm, with a mean HCD of 11.76 +/‐ 0.33 mm. The mean ACD was less in young hyperopes than in emmetropes (2.72 mm vs 2.91 mm). ACD was a further 10 % shallower in older hyperopes when compared to younger hyperopes, with the peripheral cornea also being slightly thinner (by about 4 %). No substantial differences between the younger and the older hyperopes were noted in HCD, PK, and CCT (p ≥ 0.094, independent samples t‐test), but younger hyperopes had on average a larger AK than older subjects, the difference being only just significant (p = 0.02). Conclusion These pilot studies indicate that most anterior segment biometrics are not substantially different between younger and older subjects with hyperopia. However, younger subjects had a slightly flatter anterior corneal radius and a thicker peripheral cornea, along with the expected (on average) lower ACD in hyperopic eyes and older subjects. Further studies are needed for refractive surgery procedures in older hyperopic patients.

Abstracts: 39th Annual Meeting of the American College of Veterinary Ophthalmologists, Boston, MA, USA, October 15–18, 2008

Purpose: The aim of this study was to evaluate the ocular features and intraocular pressure (IOP) in adult Red Drum Fish (Sciaenops ocellatus). Methods: All fish were anesthetized with tricaine methanesulfonate (MS-222, Western Chemicals, Ferndale, WA, USA) at 70 parts per million. The anterior segment of all fish eyes were examined with a Finnoff transilluminator and slit-lamp biomicroscopy. Binocular indirect ophthalmoscopy was performed in all eyes to observe the posterior segment. IOP was measured and recorded in both eyes of 13/18 fish and in the right eye only in 1/18 fish using applanation tonometry (27/36 total eyes). Tonometry readings were discarded in 4 fish (8 eyes) due to poor anesthesia and inadequate restraint. The horizontal corneal diameter was measured in all eyes. Results: There were 9 male and 9 female fish, all of which were 5 years old. Ophthalmic examination of the anterior segment revealed a horizontal oval-shaped immobile pupil. A characteristically large spherical lens and shallow anterior chamber often exhibiting an aphakic crescent medially was observed. The retina was anangiotic and the fundus ranged in color from white-gray to dark yellow-gray. The optic nerve papilla was horizontally elongated and associated with a prominent hyaloid vessel projecting anteriorly into the vitreous. In 2/36 eyes, 2 mm white translucent cysts in the anterior chamber were identified. Seventeen of the fish had anterior subcapsular opacities in both eyes. These lens opacities were between 1 and 5 mm in diameter and ranged in density from faint to prominent. The subcapsular opacities were central to paraxial. One eye had multifocal lens opacities. The mean horizontal corneal diameter of both eyes was 20.83 ± 1.42 mm. The mean IOP for the right and left eye of fish was 8.69 ± 3.29 mmHg and 6.82 ± 3.19 mmHg, respectively. Mean fish length was 99.05 ± 4.33 cm. Conclusions: The ocular features of a group of adult Red Drum Fish were identified. In this population of red drum, anterior subcapsular cataracts were a common finding. The average IOP this population of fish was determined to be 7.82 ± 2.82 mmHg.

Evaluation of the relationship between corneal diameter and lens diameter

To investigate the relationship between corneal diameter (white to white) (WTW) and the dimensions of the crystalline lens. Private practice, Cincinnati, Ohio, USA. Human cadaver eyes were oriented to allow caliper measurements of the horizontal and vertical corneal diameters (WTW). Globes were sectioned and reoriented so the horizontal and vertical measurements of the crystalline lens were recorded and statistically analyzed. The mean horizontal corneal diameter was 11.46 mm, approximately 0.8 mm greater than the mean vertical corneal diameter of 10.63 mm. The mean horizontal crystalline lens diameter was 9.28 mm, nearly identical to the mean vertical diameter of 9.30 mm. The correlation between the mean corneal diameter and mean lens diameter was weak, although it was significant. There was no correlation between horizontal dimensions. It was not possible to predict the dimensions of the human crystalline lens using calipers to measure the WTW corneal diameter.

Corneal diameters in infants born in two hospitals in Ibadan, Nigeria

To measure the horizontal corneal diameters in infants at birth and compare with values reported in other studies. A cross-sectional hospital based study. All the healthy infants born within the period of one month in these hospitals were eligible for enrolment into the study. Horizontal corneal diameter measurements were performed with indirect caliper in both eyes of each of the 342 healthy full term infants and 25 preterm healthy infants born in these two hospitals. These results were evaluated according to the age of the infants The corneal diameter in term infants was found to range from 9.00 mm to 12.50 mm during the first week of life with a mean of 10.26 mm (SD +/-0.59 mm, n = 64). This is higher than what was reported for Caucasian infants (P < 0.01). Mean horizontal corneal diameter in all male infants aged 1-238 days was 11.06 mm (SD 0.75 mm, n = 187), slightly higher than 10.93 mm (SD 0.22 mm, n = 154) in all females, though this difference was not statistically significant. Horizontal corneal diameter increased progressively with age, from a mean value (SD) of 10.26 mm (0.72) to a mean value (SD) of 12.0 mm at 34 weeks of age. There was no significant difference in the mean corneal diameter of the right and left cornea. A few infants had corneal diameters of 12.50 mm and had no congenital glaucoma. Mean corneal diameter in preterm infants less than 37 weeks of gestation was 8.90 mm at birth (SD 1.25 mm, n = 25). The horizontal diameter increased with age from birth to the 34 weeks of age. Changes after this period were not studied. The values obtained in these African infants were slightly higher than those reported from other populations.

Central corneal thickness in koi fish: effects of age, sex, body length, and corneal diameter

To establish the central corneal thickness (CCT) of normal koi fish by ultrasonic pachymetry, and its relationship to age, sex, body length and corneal diameter. Age, sex and body length of 33 koi fish (17 male and 16 female fish) were recorded. Horizontal and vertical corneal diameters of each eye were obtained using Jameson calipers. Central corneal thickness of all eyes was measured by ultrasonic pachymetry. Intraocular pressure (IOP) by rebound tonometry was obtained for a subgroup of nine koi (18 eyes). Mean central corneal thickness was 325.9 microm. Central corneal thickness of female koi was greater than CCT of male fish (P < 0.01). Central corneal thickness increased with increasing age overall and within both sexes (P < 0.01). Central corneal thickness increased with increasing body length (P < 0.001). For male and female fish, CCT increased with increasing horizontal and vertical corneal diameters (P < 0.01). Mean horizontal corneal diameter (HCD) was 8.05 mm, mean vertical corneal diameter (VCD) was 7.38 mm, and HCD was consistently greater than VCD. Mean IOP of a subgroup of these koi was 4.9 mmHg by rebound tonometry. Koi CCT increases with increasing age, body length and corneal diameter.

Predictive value of preoperative central corneal thickness for aphakic glaucoma in congenital cataract patients

Introduction: The purpose of this study was to determine if preoperative central corneal thickness (CCT) is a predictor of future glaucoma in infants undergoing cataract surgery. Methods: A retrospective chart review was performed for infants who underwent cataract surgery from January 1995 to June 2002. Inclusion required surgery prior to 1 year of age, preoperative CCT measurements, and follow-up of 3 years or longer. We excluded eyes with anterior segment dysgenesis, preoperative glaucoma, and microphthalmia. In patients with bilateral cataracts, one eye was randomly chosen for statistical analysis. Results: In eyes without glaucoma (n = 35), the mean CCT was 0.559 mm (CI = 0.542-0.572); mean horizontal corneal diameter was 10.17 mm, and mean age at surgery was 2.8 months. Eyes that developed aphakic glaucoma (n = 7) had a mean CCT of 0.597 mm (CI = 0.567-0.628), mean diameter of 10.21 mm, and a mean age at surgery of 1.5 months. Preoperative CCT was significantly greater in eyes that developed aphakic glaucoma compared with those who did not (p = 0.029). Neither corneal diameter nor age at the time of surgery was significantly different between the two groups. CCT and corneal diameter were weakly correlated (r = −0.026, p = 0.10). Discussion: CCT has become an important factor in glaucoma management. Our data suggest that eyes with congenital cataracts that develop postoperative glaucoma may also have increased CCT preoperatively. Surgeons should consider measuring CCT as part of the routine preoperative cataract evaluation. Conclusions: Thicker preoperative CCT in eyes with congenital cataract may have a predictive value for the development of postoperative aphakic glaucoma.

OPHTHALMIC EXAMINATION OF THE CAPTIVE WESTERN LOWLAND GORILLA (GORILLA GORILLA GORILLA)

This study examined the captive western lowland gorilla (Gorilla gorilla gorilla) eye as compared and contrasted with the human eye. Bilateral ophthalmic examinations of western lowland gorillas (n = 5) while under general anesthesia were performed opportunistically, including slit-lamp biomicroscopy, dilated fundus examination, cycloplegic retinoscopy, Schiotz tonometry, corneal diameter and thickness measurements, A-scan and B-scan ultrasonography, keratometry, and cultures of the eyelid margins and bulbar conjunctiva. Mean spherical equivalent refractive error by cycloplegic retinoscopy was +1.20 +/- 0.59 diopters. Mean intraocular pressure by Schiotz tonometry was 12.0 +/- 4.3 mm Hg. Mean optic nerve head cup to disc ratio was 0.42 +/- 0.11. Mean horizontal corneal diameter was 13.4 +/- 0.8 mm, and mean vertical cornea diameter was 12.7 +/- 0.8 mm. Mean central corneal thickness by ultrasound pachymetry was 489 +/- 52 microm. Mean axial length of the eye by A-scan was 22.75 +/- 0.71 mm. Mean lens thickness by A-scan was 4.23 +/- 0.34 mm. Mean anterior chamber depth by A-scan was 4.00 +/- 0.26 mm. Mean keratometry reading was 44.38 +/- 1.64 diopters. Eyelid margin and bulbar conjunctival cultures isolated Candida sp. (n = 5), Staphylococcus aureus (n = 4), Staphylococcus epidermidis (n = 3), Staphylococcus saccharolyticus (n = 3), and Micrococcus sp. (n = 3). This study suggests important similarities between western lowland gorilla and human eyes. These similarities may allow diagnostics, techniques, and equipment for human eye surgery, such as those used for cataract extraction and intraocular lens implantation, to be successfully utilized for gorillas.

Comparison of manual and automated methods to determine horizontal corneal diameter

Purpose: To compare 2 manual methods and 2 automated devices for measuring the horizontal corneal diameter (white-to-white [WTW] distance). Setting: Department of Ophthalmology, Johann Wolfgang Goethe-University, Frankfurt am Main, Germany. Methods: In 100 eyes of 61 patients, the WTW distance was measured independently by 2 examiners using the following techniques: the Holladay-Godwin gauge, a measuring caliper, Zeiss IOLMaster, and Orbscan® II topography system (Bausch & Lomb). The results were compared with measurements on magnified slitlamp photographs of the anterior eye segment. Statistical evaluation was performed using the Bland-Altman method for comparison of measurement techniques. Results: The mean horizontal corneal diameter was 11.91 mm ± 0.71 (SD) with the measuring caliper, 11.8 ± 0.60 mm with the Holladay-Godwin gauge, 11.78 ± 0.43 mm with the Orbscan II, and 12.02 ± 0.38 mm with the IOLMaster. The coefficient of inter-rater repeatability was 1.30 for the caliper, 0.92 for the Holladay-Godwin gauge, 0.76 for the Orbscan II, 0.50 for the IOLMaster, and 1.16 for the manual measurement in anterior segment images. The results obtained with the caliper were statistically significantly different between the 2 examiners ( P<.001). The measurements of examiner 2 using the caliper were significantly different from the measurements of the same examiner using the Holladay-Godwin gauge. This was not the case with the 2 automated devices. Conclusions: Automated measurement of the WTW distance provides more precise results than measurements using manual methods. The Zeiss IOLMaster had the highest reliability in measuring corneal diameter.

Assessments of corneal endothelial cell density in growing children and its relationship to horizontal corneal diameter.

Few studies have been published of corneal endothelial cell density (ECD) in children, especially in relation to the age and corneal size of the individuals. The possible effect of corneal enlargement on the endothelium was studied, and the results were objectively reviewed in relation to literature reports on corneal diameter and age. ECD was assessed in 119 children aged 5 to 15 years after endothelial photography with a noncontact specular microscope (Topcon SP-1000 or SP-2000P), followed by manual digitization of cell overlays. The horizontal corneal diameter, as the visible iris diameter, was measured to 0.5-mm accuracy. The mean +/- SD value for ECD, calculated using all individual cell area values, was 3542 +/- 510 cells/mm2 (range, 2576 to 5316), whereas it was 3246 +/- 416 cells/mm2 (range, 2404 to 4817) if the mean cell area value from each image was used to calculate ECD. The mean horizontal corneal diameter was 11.48 +/- 0.58 mm (+/- SD). The corneal diameter was not obviously age-related for this group, but there were clear trends for younger children to have higher ECD values than older children (p2, depending on the method for calculating ECD. ECD values were found to be significantly correlated to corneal diameter in children aged 5 to 15 years, and this factor should be considered in comparative studies.