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Recently, a family of homologous genes was identified, comprising EXT1 on 8q23->q24 and EXT2 on 11p12->p11, both causing multiple exostoses, and three EXT-like genes mapped on 1p36.1, 1p12->p11 and 8p22->p12 respectively. Functional studies have revealed that the EXT genes and EXTL2 are involved in heparan sulfate biosynthesis, while EXTL3 is thought to encode a receptor for Reg-proteins. However, the function of EXTL1 still remains to be elucidated. Here, we describe the mapping of the mouse Extl1 gene to the distal part of mouse chromosome 4.

Recently developed chatbots based on large language models (further called bots) have promising features which could facilitate medical education. Several bots are freely available, but their proficiency has been insufficiently evaluated. In this study the authors have tested the current performance on the multiple-choice medical licensing exam of University of Antwerp (Belgium) of six widely used bots: ChatGPT (OpenAI), Bard (Google), New Bing (Microsoft), Claude instant (Anthropic), Claude+ (Anthropic) and GPT-4 (OpenAI). The primary outcome was the performance on the exam expressed as a proportion of correct answers. Secondary analyses were done for a variety of features in the exam questions: easy versus difficult questions, grammatically positive versus negative questions, and clinical vignettes versus theoretical questions. Reasoning errors and untruthful statements (hallucinations) in the bots' answers were examined. All bots passed the exam; Bing and GPT-4 (both 76% correct answers) outperformed the other bots (62-67%, p = 0.03) and students (61%). Bots performed worse on difficult questions (62%, p = 0.06), but outperformed students (32%) on those questions even more (p<0.01). Hallucinations were found in 7% of Bing's and GPT4's answers, significantly lower than Bard (22%, p<0.01) and Claude Instant (19%, p = 0.02). Although the creators of all bots try to some extent to avoid their bots being used as a medical doctor, none of the tested bots succeeded as none refused to answer all clinical case questions.Bing was able to detect weak or ambiguous exam questions. Bots could be used as a time efficient tool to improve the quality of a multiple-choice exam., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Morreel et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Competing Interests: Conflict of interest: None declared.

Background/objective: Anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM) are two non-invasive imaging techniques used for the measurement of tumour thickness in corneal and bulbar conjunctival tumours. Histopathology (HP), however, remains the gold standard for the measurement of tumour thickness. The aim of this study was to determine whether AS-OCT and UBM are as accurate as HP for measuring tumour thickness., Methods: Forty-two corneal and bulbar conjunctival tumours were imaged using AS-OCT and UBM. Images were assessed and tumour thickness was measured. Eleven patients subsequently underwent surgical excision. All specimens were measured during histopathological analysis. The correlation of the thickness measurement on HP to AS-OCT and UBM was then statistically analysed. In cases where the tumour was not excised, thickness measurement comparisons between AS-OCT and UBM were analysed., Results: AS-OCT and UBM measurements of tumour thickness were found to be significantly positively correlated (p=<0.001), as were UBM and HP thickness measurements (p=0.031). HP and AS-OCT measurements, however, only showed a mild but non-significant positive correlation., Conclusion: Both AS-OCT and UBM are useful techniques to image and measure the thickness of corneal and conjunctival bulbar tumours. While AS-OCT provides better details than UBM, it was more limited in visualising the posterior boundary of the tumour, particularly in malignant tumours. While thickness measurements of both methodologies were correlated, neither should yet be considered as replacements to the gold standard of HP., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose: To report the status of Berger space in pediatric cataract cases and the influence of anterior vitreolenticular interface dysgenesis during primary posterior continuous curvilinear capsulorhexis (PCCC)., Setting: Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium., Design: Prospective case series., Methods: The study comprised consecutive pediatric cataract cases planned for bag-in-the-lens intraocular lens (BIL IOL) implantation. A video-based analysis of the surgical interventions included the type of crystalline lens opacification, presence of a posterior capsule plaque (PCP), presence of anterior vitreolenticular interface dysgenesis, complications during primary PCCC, integrity of the anterior hyaloid membrane, need for anterior vitrectomy, and feasibility of BIL IOL implantation., Results: Abnormalities in Berger space were observed in 35 of the 64 pediatric cataract cases. Anterior vitreolenticular interface dysgenesis was most often found in cases with persistent fetal vasculature (PFV) and those with posterior cataract. Anterior vitreolenticular interface dysgenesis was diagnosed significantly more often in eyes with unilateral cataract and those with PCP. In pediatric cataract cases presenting with PCP and anterior vitreolenticular interface dysgenesis, the primary PCCC procedure was surgically more demanding, often resulting in detectable breaks in the anterior hyaloid membrane (58.6%) and sometimes necessitating an unplanned anterior vitrectomy (13.8%). Bag-in-the-lens IOL implantation was feasible in all except 1 eye with PFV, which was left aphakic., Conclusions: Primary vitreolenticular interface abnormalities are often encountered during pediatric cataract surgeries, especially when confronted with PCP in a unilateral cataract. The presence of anterior vitreolenticular interface dysgenesis may complicate a primary PCCC procedure, resulting in an unplanned anterior vitrectomy in some cases., (Copyright © 2018. Published by Elsevier Inc.)

Purpose: To evaluate the effect of benzalkonium chloride-assisted (BAC) transepithelial collagen crosslinking (CXL) in eyes with progressive keratoconus and a minimum follow-up of 6 months., Setting: Department of Ophthalmology, Antwerp University Hospital, Antwerp, Belgium., Design: Cohort study., Methods: Eyes with progressive keratoconus had CXL treatment without epithelial debridement. The standard CXL irradiation was preceded by instillation of proparacaine drops 0.5% preserved with BAC 0.005% every 5 minutes for 30 minutes. Selected parameters of refraction assessed by Placido disk (Eyesys) and Scheimpflug (Pentacam) examinations were compared before CXL and after CXL at 6, 12, and 18 months., Results: The study enrolled 53 eyes of 38 patients. Sphere, cylinder, as well as maximum keratometry (K max) simulated K values (steep, flat, astigmatism), and refractive power values (steep, flat, astigmatism) measured using the Placido disk device remained stable over the 18-month follow-up. Only corrected distance visual acuity showed a statistically significant improvement at 6 months and 12 months. The Scheimpflug device measurements of maximum K and pachymetry at the thinnest point showed statistically significant progression throughout the study. No patient developed corneal haze or other complications., Conclusion: Transepithelial CXL using proparacaine drops 0.5% preserved with BAC 0.005% was less effective than standard CXL in stabilizing progressive keratoconus., (Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Purpose: To assess the clinical outcomes of bag-in-the-lens intraocular lens (BIL IOL) implantation following the International Organization for Standardization (ISO) 11979-7:2006 in pediatric eyes and eyes with ocular comorbidities., Setting: Antwerp University Hospital, Department of Ophthalmology, Antwerp, Belgium., Design: Cohort study., Methods: This cohort included the first series of patients having IOL implantation using the bag-in-the-lens technique. Surgeries were performed between December 1999 and September 2006. In addition to IOL implantation, the technique comprised creation of a primary posterior continuous curvilinear capsulorhexis (PCCC) equal in size to the anterior capsulorhexis., Results: The study enrolled 807 eyes of 547 patients; 326 of the eyes (40.40%) had ocular comorbidity. In the 481 eyes without ocular comorbidity, the mean decimal corrected distance visual acuity was 0.52 ± 0.24 (SD) (0.276 ± 0.206 logMAR) preoperatively and 0.94 ± 0.18 (-0.012 ± 0.053 logMAR) postoperatively. The mean postoperative achieved spherical equivalent was 0.48 ± 0.83 diopter (D) and the mean targeted refraction, -0.24 ± 0.71 D. The A-constant was modified from 118.4 to 118.04. Posterior capsule opacification (PCO) did not occur in any adult eye during the follow-up. Retinal detachment after IOL implantation occurred in 10 eyes (1.24%). In 19 eyes, the iris was captured by the IOL haptics postoperatively. Hypopyon occurred in 3 patients and toxic anterior segment syndrome in 1 patient., Conclusion: The BIL IOL met the ISO criteria; that is, primary PCCC was safe in healthy eyes and in eyes with ocular comorbidities and no eye developed PCO over a mean follow-up of 26.1 ± 21.3 months., (Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Aims: To report on the influence of rigid gas permeable contact lens (CL) wear on the results of ultraviolet A/riboflavin cross-linking (CXL) for stabilisation of progressive keratoconus., Methods: Prospective non-comparative study of 15 eyes without CL and 12 eyes fitted with CL from 1 to 10 weeks post-CXL. None of the patients had been wearing CL before CXL. The effect of the CXL treatment was measured by the change from the baseline of best spectacle corrected visual acuity (BSCVA), refractive sphere and cylinder, maximal keratometry value (K max), simulated keratometry steep, flat, astigmatism, refractive power (RP) steep, flat and astigmatism, I-S value on EyeSys (EyeSys Vision Inc, Houston, Texas, USA) and K max on Pentacam (Oculus Optikgeräte, Wetzlar, Germany). The results of these measurements are reported pre-CXL and at 6-month intervals up to 18 months post-CXL. Results In the eyes without CL, none of the study parameters showed a significant change from baseline. Only in the group of eyes fitted with CL post-CXL, several parameters showed a significant improvement: I-S value and K max on EyeSys (all time points), RP steep and simulated astigmatism (6 and 12 months) and RP flat (12 months)., Conclusion: CL can be a confounding factor in interpreting the results of CXL: lens wear itself leads to improved topographic parameters.

Purpose: To propose a method of calculating the power of the 1-sided posterior chamber toric bag-in-the-lens (BIL) intraocular lens (IOL) and propose a misalignment nomogram to calculate the postoperative rotational misalignment or predict the effect of preoperative existing irregular corneal astigmatism., Setting: Antwerp University Hospital, Department of Ophthalmology, Antwerp, Belgium., Design: Cohort study., Methods: The new IOL calculation formula uses the steepest corneal meridian and flattest corneal meridian separately (regular spherical IOL formula) followed by a customized A-constant approach based on the changes in the IOL principal plane depending on the spherical and cylindrical powers (thickness) of the IOL. The calculation of the remaining astigmatism (power and axis) in cases of postoperative rotational misalignment resulted in a nomogram that can also be used to predict the degree of tolerance for irregular corneal astigmatism correction at the lenticular plane. The calculation is performed using a worksheet., Results: Because 10 degrees of misalignment would result in 35% refractive inaccuracy, it is the maximum acceptable corneal astigmatic irregularity for correction at the lenticular plane., Conclusions: Calculation of spherocylindrical power is specific to each toric IOL. Because the surgeon must fully understand the optical properties of the toric IOL that is going to be implanted, a comprehensive outline of a new calculation method specific to the toric BIL IOL is proposed. Primary rotational misalignment of the toric BIL IOL can be fine tuned postoperatively., Financial Disclosure: Drs. Gobin and Mathysen have no financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes., (Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate the clinical results after implantation of a spherotoric intraocular lens (IOL) using the bag-in-the-lens (BIL) technique., Setting: Antwerp University Hospital, Department of Ophthalmology, Antwerp, Belgium., Design: Evidence-based manuscript., Methods: Consecutive eyes with cataract and corneal astigmatism had implantation of a spherotoric BIL intraocular lens (IOL). The IOL was centered based on the patient's pupillary entrance using Purkinje reflexes of the surgical microscope light., Results: The study enrolled 52 eyes of 35 patients (23 women) with corneal astigmatism ranging from 0.90 to 6.19 diopters (D). The toric power was between 1.00 D and 8.00 D. One-third of eyes had an additional ocular comorbidity (including amblyopia) that could influence the clinical outcomes; 5.2% had an irregular astigmatism up to 15 degrees. Twelve eyes had high myopia (axial length [AL] >26 mm) and 5 eyes, high hyperopia (AL <21 mm). The mean preoperative corrected distance visual acuity was 0.58 ± 0.25 (SD). Postoperatively, the uncorrected distance visual acuity (UDVA) was 0.5 or better in 92% of eyes, the mean UDVA was 0.85 ± 0.21 D, the mean magnitude of error was 0.05 ± 0.49 D, and the mean angle of error was 0.29 ± 0.89 degree. Astigmatism correction was successful in 82% of eyes., Conclusion: Spherotoric BIL IOL implantation yielded outcomes similar to those with other spherotoric IOLs, even in eyes with ocular comorbidity or irregular astigmatism up to 15 degrees., (Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

The osteopetroses are a heterogeneous group of genetic conditions characterized by increased bone density due to impaired bone resorption by osteoclasts. Within the autosomal dominant form of osteopetrosis, the radiological type I (ADOI) is characterized by a generalized osteosclerosis, most pronounced at the cranial vault. The patients are often asymptomatic but some suffer from pain and hearing loss. ADOI is the only type of osteopetrosis not associated with an increased fracture rate. Linkage analysis in two families with ADOI from Danish origin enabled us to assign the disease-causing gene to chromosome 11q12-13. A summated maximum lod score of +6.54 was obtained with marker D11S1889 and key recombinants allowed delineation of a candidate region of 6.6 cM between markers D11S1765 and D11S4113. Previously, genes causing other conditions with abnormal bone density have been identified from this chromosomal region. The TCIRG1 gene was shown to underly autosomal recessive osteopetrosis (ARO), and, recently, mutations in the LRP5 gene were found both in the osteoporosis-pseudoglioma syndrome and the high bone mass trait. Because both genes map within the candidate region for ADOI, it can not be excluded that ADOI is caused by mutations in either the TCIRG1 or the LRP5 gene.