Mean Corneal Diameter Research Articles

An Analysis of Ocular Biometrics: A Comprehensive Retrospective Study in a Large Cohort of Pediatric Cataract Patients.

Objectives: This study aims to provide a comprehensive analysis of ocular biometric parameters in pediatric patients with cataracts to optimize surgical outcomes. By evaluating various biometric data, we seek to enhance the decision-making process for intraocular lens (IOL) placement, particularly with advanced technologies like femtosecond lasers. Methods: This retrospective comparative study included pediatric patients with cataracts who underwent ocular biometric measurements and cataract extraction with anterior vitrectomy at the Medical University of Vienna between January 2019 and December 2021. Parameters measured included corneal diameter (CD), axial length (AL), corneal thickness (CT) and flat and steep keratometry (Kf and Ks). The study explored the correlations between these parameters and IOL placement. Results: A total of 136 eyes from 68 pediatric patients were included in the study. Significant positive correlations were found between corneal diameter, age and AL. The mean CD was 11.4 mm, mean AL was 19.5 mm, CT was 581.2 ± 51.8 µm, Kf was 7.76 ± 0.55 mm and Ks 7.41 ± 0.59 mm, respectively. Older pediatric patients with larger corneal diameters and longer ALs were more likely to receive in-the-bag IOL implantation. Conversely, younger patients often required alternative IOL placements or remained aphakic. Our data indicated that over 95% of the study population and all patients aged one year and older had a corneal diameter of 10 mm or larger. Conclusions: Detailed ocular biometric analysis is crucial for optimizing both surgical outcomes and postoperative care in pediatric cataract patients. The positive correlations between CD, age and AL underline the importance of individualized surgical planning tailored to each patient's unique anatomical features. Additionally, our findings suggest that the use of a femtosecond laser is both feasible and safe for pediatric patients aged one year and older, potentially offering enhanced surgical precision and improved outcomes.

Couching of cataractous lens in microphthalmic eyes with irido-fundal coloboma: revisiting the historical technique.

Cataract surgery in microphthalmic eyes is challenging due to anatomical restraints, hard bulky nucleus. This series aims to evaluate the safety and efficacy of couching of intraocular lens in irido-fundal coloboma with microphthalmos. Tertiary care centre in South India. Retrospective non-comparative study in eyes with irido-fundal coloboma, corneal diameter < 7mm and brown cataract. Visual acuity less than 6/60 in other eye. Anterior chamber entry made, zonules broken and lens dislocated into the vitreous cavity in a controlled manner. Baseline Clinico-demographic details, corrected distance visual acuity (CDVA), Intra-ocular pressure (IOP), corneal diameter, axial length, lens status and post-surgery CDVA, IOP and complications recorded and followed up for atleast 6months. Fifteen eyes of 15 subjects were evaluated with a mean age 49.4 ± 10.9years. At baseline, mean IOP 14.5 ± 3.8mmHg, mean axial length 19.3 ± 0.5mm, mean corneal diameter was 6.5 ± 0.34mm and CDVA 2 logMAR which improved to 1.5 logMAR at 3months (p value 0.002). Transient spike in IOP in 33.3% subjects was medically managed with no significant difference in IOP (p > 0.05) at baseline (14.5 ± 3.8mmHg), 3months post-surgery (16 ± 2.8mmHg) and 6months post-surgery (14.9 ± 2.5mmHg). One patient underwent re-couching. No other major complications were noted. Couching of cataractous lens is an effective and safe method in microphthalmic eyes with irido-fundal coloboma as last resort procedure, where no other surgical procedure may work. It provides an ambulatory gain of visual acuity in previously non-ambulatory subjects. Corneal measurements help in determining the subset of patients where couching offers viable option.

Comparing the Use of Smartphone and Vernier Calipers for Corneal Diameter Measurement in Nigerian Term Neonates.

Corneal diameter (CD) measurement in newborns is essential for the detection of blinding ocular pathologies. It requires specially trained personnel, contact techniques, and the use of anesthesia. Smartphone use may obviate these challenges. This study compares CD measurement among newborns using a Smartphone and manual calipers. This is a cross-sectional comparative study done at Alex Ekwueme Federal University Teaching Hospital, Abakaliki, Nigeria. Consecutively selected stable term neonates whose mothers consented to the study and met the inclusion criteria had their CDs measured with both calipers and smartphones and the values compared. Mean, range, and standard deviation were calculated using Statistical Package for the Social Sciences (SPSS) IBM (version 22), while paired t-test calculated the difference in mean CD measurements between both methods. Pearson's correlation and Bland-Altman's analysis determined the correlation and agreement between both methods, respectively. Inter and intraobserver repeatability were assessed. A P value less than 0.05 was taken as statistically significant. The mean CD measurement using calliper method was 10.01 ± 0.29mm and 10.03 ± 0.24 mm right eye (RE) and left eyes (LE), respectively) for investigator 1 and 10.16 ± 0.25 mm and 10.19 ± 0.21 mm (RE, LE) for investigator 2. Using smartphone measurement, mean CD measurements of 9.98 ± 0.21 mm and 10.00 ± 0.29 mm (RE, LE) were observed for investigator 1 and 10.07 ± 0.19 mm and 10.06 ± 0.21 mm (RE, LE) for investigator 2. The difference in mean CD for both instruments and by both investigators was not statistically significant (P value > 0.05). Corneal diameter measurement in neonates using smartphone technology does not deviate significantly from caliper measurement; it is safe, easy to use, and advocated.

Investigation of ocular biometry in 4– to 9-year-old Chinese children

PurposeTo investigate the distribution and changes in ocular biometry in 4-to to 9-year-old Chinese children and to compare the differences between age and genders in these parameters.MethodsThis was a school-based cross-sectional study. A total of 1,528 Chinese children, aged 4–9 years, from one primary school and 12 kindergartens, were included in the study. Axial length, corneal curvature, anterior chamber depth, and corneal diameter were measured for each child.ResultsAL and anterior chamber depth gradually increased with age in both genders. No significant changes in corneal curvature or corneal diameter were detected at different ages in either genders group. The mean ALs of males and females were 22.94 ± 0.80 mm and 22.38 ± 0.79 mm, respectively. The mean corneal curvatures of males and females were 43.05 ± 1.37 D and 43.75 ± 1.48 D, respectively. The mean anterior chamber depth of males and females were 3.47 ± 0.24 mm and 3.38 ± 0.25 mm, respectively. The mean corneal diameter of males and females were 12.08 ± 0.43 mm and 11.94 ± 0.44 mm, respectively. Females had consistently shorter ALs, shorter anterior chamber depth, smaller corneal diameter, and steeper corneal curvatures than males at any age.ConclusionsBoys had larger dimensions than girls for all ocular parameters except corneal curvature (flatter). Boys and girls showed similar trends for all parameters. Axial length and anterior chamber depth increased from 4 to 9 years of age, whereas corneal diameter and curvature did not change with age in either genders.

Agreement of Corneal Diameter and Anterior Chamber Depth Measurements with the IOLMaster 500 and the IOLMaster 700 Optical Biometers in Myopic Eyes.

To assess the agreement in automated corneal diameter (CD) and anterior chamber depth (ACD, measured from corneal epithelium to lens) distances measurements between the IOLMaster 500 and 700 optical biometers in myopic eyes. One hundred and sixteen eyes of 116 myopic patients aged between 21 to 60 years were included in this study. Measurements of CD and ACD distances were taken with each biometer for all patients in the same session. A t-test and a p-value less than 0.05 was considered statistically significant when the measurements were compared. The agreement between biometers was studied by applying a Bland-Altman analysis. The mean CD values obtained using the IOLMaster 500 and 700 biometers were 12.26±0.35 mm and 12.13±0.34 mm, respectively. The mean ACD distance values were 3.61±0.29 mm and 3.62±0.31, for the IOLMaster 500 and 700 biometers, respectively. There were statistically significant differences between the two devices only for CD measurements (p<0.001), but not for ACD measurements (p=0.26). The limits of agreement obtained were wide in both types of measurements, being 0.422 mm for the CD distance and 0.389 mm for the ACD distance. There were statistically significant differences between the IOLMaster 500 and 700 biometers regarding CD but not in ACD measurements in healthy myopic eyes. These differences could be clinically significant in some cases. According to these results, medical judgement should be used to assess whether the two devices could be used interchangeably for CD and ACD measurements during the clinical practice.

Microspherophakia and megalocornea with or without secondary glaucoma: A case series

AbstractPurpose: To report a case series of 6 eyes of 3 children diagnosed with microspherophakia and megalocornea with or without secondary glaucoma (MSPKA) and to discuss its clinical features and management.Methods: We reviewed 3 cases of a boy (case 1) and 2 sisters (cases 2,3) diagnosed with MSPKA from two consanguineous families. Ultrasound biomicroscopy was performed in 2 eyes and anterior‐segment swept‐source optical coherence tomography in 6 eyes.Results: Mean corneal diameter was 13 mm. Lens equatorial diameters were, in case 1, 6.2 mm in the right eye (RE) and 6.1 mm in the left eye (LE); in case 2, 7.4 mm (RE) and 7.7 mm (LE). Systemic work‐up was unremarkable.Case 1: A 6‐year‐old boy presented with bilateral lens subluxation and advanced secondary angle‐closure glaucoma (SACG). Best‐corrected visual acuity (BCVA) was 20/200 (RE) and was limited to counting fingers (LE). We performed phacoemulsification, anterior vitrectomy and retro‐pupillary iris‐claw intraocular lens implantation (RPIC‐IOL) in both eyes. At 5 months follow‐up, BCVA was 20/50 (RE) and 20/100 (LE). Intraocular pressure (IOP) decreased to 14 mmHg in both eyes.Case 2: Ophthalmologic examination in a 5‐year‐old girl showed in both eyes: a BCVA of 20/50, megalocornea, normal IOP and iridophacodonesis. Surgery with scleral fixation of the capsular bag will be considered.Case 3: An 8‐year‐old girl was referred after a bilateral lensectomy following spontaneous luxation of the lens into the anterior chamber in her RE. Examination showed bilateral megalocornea, aphakia and normal IOP. Secondary RPIC‐IOL implantation and amblyopia management were planned.Genetic testing for the Latent Transforming Growth Factor Beta Binding Protein 2 (LTBP2) gene mutation was performed in both sisters.Conclusions: MSPKA is a rare condition that can be associated with extraocular manifestations. Patients are at a high risk of lens dislocation and SACG. Surgical management remains challenging and should not be delayed.

Comparative evaluation of corneal characteristics in eyes of primary congenital glaucoma and Axenfeld‐Rieger syndrome

AbstractPurpose: To evaluate and compare the primary dysgenesis of cornea in Primary Congenital Glaucoma (PCG) and Axenfeld‐Rieger Syndrome (ARS).Methods: 26 eyes of PCG and 40 eyes of ARS were included. The following parameters were noted: clinico‐demographic profile; ASOCT of cornea/angle; Ocular biomechanical parameters, intraocular pressure (IOP) and central corneal thickness(CCT) (using Corvis ST); corneal aberration (iTrace, Tracey Technologies); morphological and cellular structure of the cornea (Confoscan HRT‐III:RCM) and histopathology of cornea (after keratoplasty).Results: Mean corneal diameter of PCG (13.4 ± 1 mm) was higher (p = 0.01) than ARS (11.7 ± 1.6 mm). Haab striae were observed more in the eyes of PCG (63.6%) than ARS (5%). Posterior corneal hyperreflectivity was present in 100% PCG eyes v/s 85.2% ARS (p = 0.006). Angle dysgenesis was comparable: PCG (85.4%) and ARS (90.7%). The presence of a double membrane sign, indicating thickened PDL and DM, was visible exclusively in eyes of PCG (29.2%) v/s singular posterior corneal hyperreflectivity (85.2%), indicating thickened DM complex, visible in eyes of ARS. Corneas of ARS were 52.3 μm thicker than PCG. In eyes of both PCG and ARS, the most common total ocular aberration was astigmatism. The endothelial cell count in PCG {1703 ± 661 cells/mm2} and ARS {1442 ± 397 cells/mm2} was comparable. The PDL thickness in the eyes of PCG (11.8 μm) was greater than ARS (9.1 μm). In immunohistochemistry, all tissues of PCG (n = 9) were collagen IV positive (indicating presence of PDL), two tissues of ARS (22.2%) were collagen IV negative.Conclusions: The difference in characteristic of PDL may cause difference in corneal enlargement and angle differences between the two groups.

Corneal diameter measurements by 3 optical biometers and their effect on phakic intraocular lens sizing.

To compare phakic intraocular lens size calculations based on corneal diameter (CD) measurements by 3 instruments. G.B. Bietti Foundation I.R.C.C.S., Rome, Italy. Retrospective interventional case series. Preoperatively, CD was measured with the Aladdin, IOLMaster 700, and Pentacam AXL Wave. The simulated ICL size was computed by entering CD measurements into the manufacturer's calculator. Postoperatively, vaulting was measured by anterior segment optical coherence tomography. The optimal ICL size (OIS) was calculated and compared with the commercially available OIS (CAOIS). 54 eyes (29 patients) with the implantable collamer lens (ICL) were enrolled. The mean CD was 12.02 ± 0.36 mm with the Aladdin, 12.35 ± 0.39 mm with the IOLMaster 700, and 12.22 ± 0.41 mm with the Pentacam AXL Wave ( P &amp;lt; .0001), with the closest agreement between the Pentacam AXL Wave and IOLMaster 700 (95% limits of agreement: -0.43 to +0.17 mm). Vaulting (mean: 558 ± 261 μm) was within 251 and 1000 μm in 49 eyes (83.3%). The mean difference between the simulated ICL size and OIS ranged between -0.11 ± 0.35 mm and 0.10 ± 0.30 mm ( P &amp;lt; .0001), with no statistically significant difference between the IOLMaster 700 and Pentacam AXL Wave. The simulated ICL size was equal to CAOIS in 38 eyes (70.37%) with the Aladdin, 37 eyes (68.52%) with the IOLMaster 700, and 39 eyes (72.22%) with the Pentacam AXL Wave, without any statistically significant difference. CD measurements by the 3 devices lead to similar percentages of eyes with an ICL size equal to the OIS. Agreement is closer between the IOLMaster 700 and Pentacam AXL Wave.

Ocular morphology of the fruit bat, Eidolon helvum, and the optical role of the choroidal papillae in the megachiropteran eye: a novel insight

This work was designed to provide a morphologic, morphometric and histochemical description of the eye of the African straw-coloured fruit bat (Eidolon helvum). An explanation of the optical role of the choroidal papillae in the vision of megachiropteran bats was provided. Enucleated eyes of captured fruit bats were measured and processed for light microscopy. Typical gross features of the mammalian eye including an anterior transparent cornea, posterior whitish sclera and a golden-brown iris surrounding a round pupil were observed in the eye. Presence of undulating retina typically found in megachiropterans was also seen. The ratio of mean corneal diameter to mean axial eye diameter was 0.58 ± 0.08. The histochemical investigation of the eye indicated the presence of mucins, proteoglycans, hyaluronic acid, glycogen and/or glycoproteins in the corneal, scleral, choroidal and retinal tissues. The presence of reflective materials of the tapetum lucidum on the undulating retina was shown to be a morphological adaptation for increased light sensitivity as each parabolic surface of the choroidal papillae served as a convex mirror, reflecting the light rays to the adjacent parabolic surface, thus sensitising photoreceptors in affected regions. This phenomenon thus empowers megachiropteran bats with improved scotopic visual capability and could explain why most of them are reliant on their vison without the need for echolocation.

Risk Factors for Trabeculotomy Failure in Primary Congenital Glaucoma.

This study demonstrates that a baseline corneal diameter >12.25, initial age <4 months at diagnosis, higher baseline IOP than 24mmHg, bilaterality, or inability to perform circumferential trabeculotomy, increases the risk of surgical failure of trabeculotomy in patients with primary congenital glaucoma (PCG). The aim of this study was to identify clinical predictive factors for surgical failure and to evaluate potential prognostic factors affecting surgical success in patients with PCG who underwent trabeculotomy. The medical charts of 123 eyes of 75 patients who underwent trabeculotomy surgery for the treatment of PCG were retrospectively reviewed. At baseline and each visit, intraocular pressure (IOP), corneal diameter, cup to disc ratio, axial length, number of medications, and need for further glaucoma surgery were noted. Surgical success was defined as an IOP ≤18mmHg and 20% IOP reduction from baseline with (qualified) or without (complete) medication and without any further IOP-lowering surgery. The mean age at surgery was 4.2±6.6 months and the mean follow-up time was 60.0±37.6 months. The receiver operating characteristic curve showed 4 following best cutoff values to predict surgical failure: the first for age at surgery was 4.5 months; the second baseline IOP was 24.0mmHg; the third for baseline cup to disc ratio was 0.4; and the fourth for baseline corneal diameter was 12.25mm. Multivariate logistic regression analysis revealed that baseline IOP more than 24mmHg increased the risk of surgical failure by 2 times, baseline mean corneal diameter >12.25mm did by 4.2 times, younger age than 4 months did by 2.5 times, bilaterality did by 1.5 times. A higher baseline IOP, younger age, larger corneal diameter, and bilaterality were identified as risk factors for trabeculotomy failure in congenital glaucoma. The presence of one or more of these should be considered in the decision-making process when considering surgical options to manage glaucoma in these patients.

Normative Values for Corneal Tomography and Comparison of Both Eyes in Young Saudi Males with 20/20 Vision Using Pentacam-HR Scheimpflug Imaging.

PurposeAnterior segment evaluation using Scheimpflug imaging with the Pentacam scanner allows the acquisition of a plethora of information. It aids in screening and diagnosing corneal pathologies and determining suitability for keratorefractive procedures. This research has significant benefits in terms of establishing normative tomographic values, which is crucial in countries where Keratoconus (KC) is more prevalent, especially among young age group, along with aiding future research in the field of refractive surgery by providing relevant normative data.MethodsA retrospective review of digital corneal tomography images for a group of medically and ophthalmologically free males aged between 18 and 21 years with 20/20 unaided distant visual acuity was performed.ResultsA total of 1272 subjects (2544 eyes) were included. Findings revealed a mean maximal corneal curvature (Kmax) of 42.91 ± 1.40D (range 36.90–47.80D). The mean flat keratometry (K1) was 41.87 ± 1.31D (range 36.00–46.40D). The mean steep keratometry (K2) was 42.66 ± 1.35D (range 36.70–47.60D). The mean corneal astigmatism (CA) was 0.79 ± 0.37D (range 0.00D-2.30D). The mean central corneal thickness (CCT) was 558.53 ± 33.84 μm (range 421–677 μm). The mean thinnest corneal location thickness (TCLT) was 551.64 ± 34.08 μm (range 417–669μm). The mean corneal diameter (CD) and anterior chamber depth (ACD) were 12.13 ± 0.39 mm (range 10.50–13.60 mm) and 3.12 ± 0.29 mm (range 2.08–4.08 mm), respectively. The median differences between both eyes of the same subject were as follows: kmax difference of 0.20D (IQR 0.1–0.4); K1, K2 and CA difference of 0.20D (IQR 0.1–0.3) for all 3 parameters; CCT and TCLT difference of 5.00 μm (IQR 3.0–9.0) and 6.00 μm (IQR 3.0–10.0), respectively; CD difference of 0.10 mm (IQR 0.0–0.1); and ACD difference of 0.04 (IQR 0.02–0.06).ConclusionWe believe our data can aid in establishing normative tomographic values and acceptable differences between both eyes. Our data may also help detect subtle corneal pathology and be useful for researchers and innovators in the field of ophthalmology.

Clinical characteristics of infants with port-wine stain and glaucoma secondary to Sturge–Weber Syndrome

BackgroundSturge–Weber Syndrome (SWS) is a rare disease involving the eye, skin, and brain. Port-wine stain (PWS) and glaucoma are common clinical manifestations. This study analysed the clinical characteristics of infants with PWS and glaucoma secondary to SWS.MethodsChildren with PWS and glaucoma secondary to SWS were enrolled. Data were extracted from ophthalmic and systemic examination findings. Ocular examinations included intraocular pressure, anterior segment and fundus examination, and ocular A-scan and B-scan ultrasonography.ResultsFifty-seven patients were included, with a mean age of 9.9 ± 11.9 months, and 34 (59.6%) patients were male. In all, 61 eyes were diagnosed with glaucoma. Forty-one patients (71.9%) had unilateral facial PWS and glaucoma occurred on the same side. Eight patients (14.0%) had Mongolian spots and ten patients (17.5%) had epilepsy. Corneal changes included corneal oedema (n = 36 eyes, 59.0%), corneal opacity (n = 15 eyes, 24.6%), and Haab lines (n = 13 eyes, 21.3%). Mean corneal diameter and thickness in the eyes with glaucoma was larger than those in the unaffected eyes (12.2 ± 0.7 mm vs 10.8 ± 0.6 mm, P < 0.001; 681.2 ± 106.4 µm vs 578.2 ± 58.2 µm, P < 0.001). The eyes with glaucoma had higher IOP and larger axial length and C/D ratio (19.3 ± 6.2 mmHg vs 11.6 ± 4.2 mmHg, P < 0.001; 21.23 ± 1.93 mm vs 19.68 ± 1.61 mm, P < 0.001; and 0.57 ± 0.18 vs 0.24 ± 0.15, P < 0.001). Thirty-three (57.9%) and 25 (43.9%) patients showed diffuse choroidal haemangioma (DCH) and conjunctival/episcleral haemangiomas, respectively. Ten patients (17.5%) showed iris anterior insertion or hyperpigmentation in the anterior chamber angles. Six of them had Mongolian spots at the same time.ConclusionsMonocular glaucoma, DCH, and conjunctival/episcleral haemangiomas are common in SWS patients with PWS and glaucoma. Glaucomatous eyes have larger corneal diameter and axial length and thicker cornea. Patients with Mongolian spots have higher incidence of iris anterior insertion or hyperpigmentation in anterior chamber angle.

Consanguinity and severity of primary congenital glaucoma

To evaluate the severity of primary congenital glaucoma (PCG) among children born of consanguineous marriage. In this case-control study, the medical records of unrelated consanguineous patients and unrelated nonconsanguineous (control) PCG patients seen at a single tertiary eye care facility were retrospectively reviewed. Those with a minimum of 5 years' follow-up were included. Data collected included age at presentation, corneal diameter, axial length, corneal haze at presentation and its persistence after surgery, need for repeat surgery, and final visual acuity. A total of 130 PCG patients were included: 30 patients born of consanguineous marriage and 100 nonconsanguineous control patients. The median age of presentation for consanguineous cases was 3 months (range, 1-36) compared with 10 months (range, 2-24) for nonconsanguineous cases (P < 0.001). Mean corneal diameter for consanguineous cases was 13 ± 0.82 mm and for nonconsanguineous cases was 12.41mm ± 1.18 mm (P = 0.002). Consanguineous cases also had a significantly higher prevalence of corneal haze persisting after surgery (P < 0.001) and need for repeat IOP-lowering surgery (P = 0.039). The consanguineous group had 44 eyes (73%) with severe PCG compared with 69 (34.5%) in the nonconsanguineous group (P < 0.001). In this study cohort, children with PCG born of consanguineous parents were more severely affected at presentation compared with children born of nonconsanguineous parents; they also had poorer outcomes with IOP-lowering surgery independent of severity at presentation. It is however possible that a founder effect with consanguinity over multiple generations could account for our observations.

Validating the use of U-tool as a novel method for measuring the corneal diameter in infants screened for congenital glaucoma.

Purpose:The Castroviejo caliper is routinely used for measuring the corneal diameter in patients with primary congenital glaucoma, but needs an examination under anesthesia (EUA) or sedation. A simple U-shaped tool was devised to aid in the estimation of the corneal diameters of patients in settings where an ophthalmic caliper is not available or EUA is not feasible.Methods:Infants presenting to the congenital glaucoma clinic posted for EUA were recruited. The demographic details of the patients such as age, sex, and diagnosis were noted. A simple U-shaped tool was devised using three Schirmer strips or a printable ruler. Before the patient underwent a EUA, the corneal diameters were measured using the U-tool. During EUA, corneal diameters were measured using the Castroviejo caliper.Results:The mean age of infants was 6.7 ± 3.39 months (R = 1–12). The mean corneal diameter measured using the U-tool was 13.29 ± 1.33 mm and with Castroviejo caliper was 13.18 ± 1.39 mm. The difference between the corneal diameters measured using the two techniques was −0.114 mm with the Bland–Altman plot 95% Limits of agreement (LoA) from −0.965 to 0.737 mm. Corneal diameters measured with both instruments had a good correlation (Pearson’s correlation coefficient = 0.95, P < 0.001).Conclusion:U-tool can be used for screening congenital glaucoma by first-contact physicians or optometrists. It can also be used by ophthalmologists when EUA is delayed.

Effect Of Trabeculectomy On Ocular Biometry And Refractive Errors In Pediatric Glaucoma

Background: Pediatric glaucoma triggers refractive errors by modifying the biometry of the eye. This study was conducted with the objective of estimating the short-term biometric and refractive changes prior to and post trabeculectomy in pediatric glaucoma. Material and Methods: A 12-month, descriptive, cross-sectional study was carried out from January to December 2019, using patients operated on for pediatric glaucoma. Pre- and post-operative biometric and refraction measurements were noted. Visual acuity, axial length, corneal diameter and refraction were obtained. All ethical requirements (anonymity, free, informed, and continuous consent) were satisfied. Data analysis was done using SPSS 20.0. Results: In the present study, 47 eyes of 27 patients were surgically operated upon, from January 2019 to December 2019 at CHU-IOTA. The predominant sex was male (17 patients) at 63%, giving a sex ratio (M / F) of 1.7. The mean age was 5.04 ± 4.24. Preoperatively, the mean corneal diameter, and D90 were respectively 13.83 ± 1.51 and 12.55 ± 0.99. Preoperatively, the mean axial length, and D90, were 23.87 ± 1.29 and 22.28 ± 1.07, respectively. Preoperatively and at three month, the mean myopia (n = 36), were respectively -3.13 ± 1.83 and -1.59 ± 0.97. The mean preoperative astigmatism (n = 47) and D90 were respectively, -1.59 ± 0.77 and -1.23 ± 0.57. A statistically significant relationship (p &lt;0.05) was found to exist between the preoperative and postoperative data of the axial length, corneal diameter, and refractive errors. Conclusions: Trabeculectomy significantly exerts a short-term positive impact on the biometrics and refraction by modifying the initial measurements and diopters.

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.

Artificial Intelligence, Machine Learning and Calculation of Intraocular Lens Power.

In the last decade, artificial intelligence and machine learning algorithms have been more and more established for the screening and detection of diseases and pathologies, as well as for describing interactions between measures where classical methods are too complex or fail. The purpose of this paper is to model the measured postoperative position of an intraocular lens implant after cataract surgery, based on preoperatively assessed biometric effect sizes using techniques of machine learning. In this study, we enrolled 249 eyes of patients who underwent elective cataract surgery at Augenklinik Castrop-Rauxel. Eyes were measured preoperatively with the IOLMaster 700 (Carl Zeiss Meditec), as well as preoperatively and postoperatively with the Casia 2 OCT (Tomey). Based on preoperative effect sizes axial length, corneal thickness, internal anterior chamber depth, thickness of the crystalline lens, mean corneal radius and corneal diameter a selection of 17 machine learning algorithms were tested for prediction performance for calculation of internal anterior chamber depth (AQD_post) and axial position of equatorial plane of the lens in the pseudophakic eye (LEQ_post). The 17 machine learning algorithms (out of 4 families) varied in root mean squared/mean absolute prediction error between 0.187/0.139 mm and 0.255/0.204 mm (AQD_post) and 0.183/0.135 mm and 0.253/0.206 mm (LEQ_post), using 5-fold cross validation techniques. The Gaussian Process Regression Model using an exponential kernel showed the best performance in terms of root mean squared error for prediction of AQDpost and LEQpost. If the entire dataset is used (without splitting for training and validation data), comparison of a simple multivariate linear regression model vs. the algorithm with the best performance showed a root mean squared prediction error for AQD_post/LEQ_post with 0.188/0.187 mm vs. the best performance Gaussian Process Regression Model with 0.166/0.159 mm. In this paper we wanted to show the principles of supervised machine learning applied to prediction of the measured physical postoperative axial position of the intraocular lenses. Based on our limited data pool and the algorithms used in our setting, the benefit of machine learning algorithms seems to be limited compared to a standard multivariate regression model.

Surgery for glaucoma in patients with facial port wine mark

To report the results of surgical treatment of glaucoma in patients with facial port wine mark at a single institution over a 10-year period. The study was conducted on 21 eyes (10 right eyes) of 17 children (8 males) with glaucoma associated with facial port wine mark presenting to the pediatric ophthalmology practice at a single institution between January 2008 and December 2017. All study eyes underwent combined angle and filtering surgery with antimetabolite (mitomycin C) and were followed for 2years. Eyes were randomized for the angle component of the procedure to conventional trabeculotomy-trabeculectomy (CTT) or viscotrabeculotomy-trabeculectomy (VTT). Success was defined as intraocular pressure (IOP) of 5-16mm Hg with no vision-threatening complications. Mean patient age was 17.4±7.5months. Mean IOP was 30.4±3.7mm Hg; mean corneal diameter, 12.4±0.5mm; mean axial length, 21.17±1.63mm; mean cup:disk ratio, 0.5±0.2; and mean number of IOP-lowering drugs at presentation, 2.6±0.5. At the end of the 2-year follow-up period, corresponding values were 12.9±0.9mm Hg, 12.6±0.4mm, 21.6±1.7mm, 0.6±0.2, and 0.1±0.3, respectively, in VTT patients and 14.3±0.7mm Hg, 12.9±0.5mm, 21.8±1.7mm, 0.6±0.2, and 0.1±0.4, respectively, in CTT groups. The most notable complication was a minimal self-limiting hyphema, more prevalent in the CTT group. In our study cohort, there were few postoperative complications associated with combined angle and filtering surgery with antimetabolites, which effectively treated elevated IOP, especially when medical treatment showed a modest response. The addition of viscoelastic to the procedure may provide additional benefits and slightly limit intra- and postoperative complications.

Myopia Prevalence and Ocular Biometry Features in a General Japanese Population: The Nagahama Study

To describe the distribution of ocular biometry and refraction in Japanese adults. Cross-sectional analysis of a prospective cohort study. A total of 9850 individuals participated in the first follow-up of the Nagahama Prospective Cohort for Comprehensive Human Bioscience (the Nagahama Study) conducted between 2013 and 2016. Participants were between 34 and 80 years of age. All participants underwent axial length (AL; in millimeters), anterior chamber depth (ACD; in millimeters), corneal diameter (white to white; in millimeters), and central corneal thickness (CCT; in micrometers) measurement (IOL Master; Carl Zeiss Meditec, Dublin, CA) and refraction (spherical equivalent [SE]; in diopters [D]) and corneal curvature (CC; in millimeters) measurement (ARK-530A; Nidek, Aichi, Japan). Distribution of these ocular biometric parameters and prevalence of myopia, high myopia, and extreme myopia were summarized. Distribution of ocular biometry and refraction. After standardization to the national population of 2015, estimates of mean AL and SE were 24.21 mm and -1.44 D, respectively. Estimates of mean CC, corneal diameter, CCT, and ACD were 7.69 mm, 12.01 mm, 543.96 μm, and 3.21 mm, respectively. After standardization of age and gender, the prevalence of myopia (SE, ≤-0.5 D) and high myopia (SE, ≤-6.0 D) were 49.97% and 7.89%, respectively. Approximately 70% of the younger participants (34-59 years of age) showed myopia, whereas high myopia was observed in approximately 10%. Although the number of individuals with myopia or high myopia was higher in the younger age groups, the prevalence of more extreme phenotypes remained stable across all ages, especially in women. Axial length of more than 30 mm was observed only in older women (n= 5 [0.05%]). We showed detailed distributions of various ocular biometry and refraction parameters using a large general Japanese cohort. Prevalences of myopia and high myopia from 2013 through 2016 were higher thanthose in earlier studies, which reflects recent environmental change. However, constant prevalence of extreme myopia across all ages suggests high genetic predisposition of the extreme phenotype.

Preliminary Anatomical Assessment of the Eye of the African Giant Rat (Cricetomys gambianus)

Eleven African giant rats were caught, bilaterally enucleated and the globes were routinely processed for light microscopy. Eye weight, vertical and horizontal corneal diameters, as well as vertical, horizontal and axial eye diameters were obtained from each globe. Observed external macroscopic ocular features were typical of mammalian eyes comprising cornea, sclera and attached extraocular muscles. The eye dimensions were however generally smaller than those of humans. The large mean corneal diameter to mean eye diameter ratio of 0.86 as well as the scanty retinal ganglion cells observed are associated with morphological adaptations for nocturnal vision. Pigments observed in the retinal epithelium suggests absence of tapetum lucidum, indicating a sub-optimal nocturnal visual capability. This study has provided scientific documentation of some ocular morphological characteristics of the giant rat and has shown that the eye of this species will be anatomically unsuitable for xenotransplantation in humans.