The morphology and natural history of childhood cataracts

Early Diagnosis of Syndromic Congenital Cataracts in a Large Cohort of Congenital Cataracts

PURPOSE

To explore the factors related to the diagnosis yield of syndromic congenital cataracts and describe the phenotype-genotype correlation in congenital cataract patients.

DESIGN

Prospective cohort study.

METHODS

Setting: the participants from underwent clinical examinations between 2021 and 2022. Facial and anterior eye segment photographs, pre- and postoperative ocular parameters, and medical and family histories were recorded. Bioinformatics analysis was performed using whole-exome sequencing data. Statistical and correlation analyses were performed using the basic characteristics, deep phenotype, and genotype data.

PARTICIPANTS

115 patients with unrelated congenital cataract.

INTERVENTIONS

performing clinical examinations, whole-exome sequencing, and bioinformatics analysis for all participants.

MAIN OUTCOMES AND MEASURES

factors related to the genetic diagnosis yield of syndromic congenital cataracts.

RESULTS

Bilaterally asymmetrical cataracts were identified to be associated with syndromic congenital cataracts. The overall genetic diagnostic yield in the cohort was 72.2%. In total, 34.8% of the probands were early diagnosed with various syndromes with the help of genetic information. A phenotype-genotype correlation was detected for some genes and deep phenotypes.

CONCLUSIONS

We highlight the importance of screening syndromic diseases in the patients with asymmetrical congenital cataracts. Application of whole-exome sequencing helps provide early diagnosis and treatment for the patients with syndromic congenital cataracts. This study also achieved a high genetic diagnostic yield, expanded the genotypic spectrum, and found phenotype-genotype correlations. A comprehensive analysis of cataract symmetricity, family history, and deep phenotypes makes the genotype prediction of some congenital cataract patients possible.

Untreated combined persistent fetal vasculature with "coralliform" cataract in a Hispanic 21 year-old male

Persistent fetal vasculature is a spectrum of ocular abnormalities linked to an incomplete regression of the fetal ocular vasculature. A 21-years old male patient came to the outpatient clinic reporting low vision and strabismus in his left eye since 3 years of age. Ophtalmological examination revealed a normal right eye, while the left eye had a best corrected visual acuity of hand-motion perception, a 30 prism diopters esotropia, a "coralliform" cataract and a vitreous stalk joining the posterior face of the lens and the optic nerve. The coralliform cataract possessed spindle-shaped processes radiating out of its center in an axial direction and was located in the posterior subcapsular area. The patient elected to not undergo vitreoretinal surgery due to the poor visual prognosis. The unusual cataract present in the described patient could be related to his untreated status, as previous authors have reported that untreated cataracts in persistent fetal vasculature may undergo diverse degenerations.

Through the Cat-Map Gateway: A Brief History of Cataract Genetics

Clouding of the transparent eye lens, or cataract(s), is a leading cause of visual impairment that requires surgical replacement with a synthetic intraocular lens to effectively restore clear vision. Most frequently, cataract is acquired with aging as a multifactorial or complex trait. Cataract may also be inherited as a classic Mendelian trait-often with an early or pediatric onset-with or without other ocular and/or systemic features. Since the early 1990s, over 85 genes and loci have been genetically associated with inherited and/or age-related forms of cataract. While many of these underlying genes-including those for lens crystallins, connexins, and transcription factors-recapitulate signature features of lens development and differentiation, an increasing cohort of unpredicted genes, including those involved in cell-signaling, membrane remodeling, and autophagy, has emerged-providing new insights regarding lens homeostasis and aging. This review provides a brief history of gene discovery for inherited and age-related forms of cataract compiled in the Cat-Map database and highlights potential gene-based therapeutic approaches to delay, reverse, or even prevent cataract formation that may help to reduce the increasing demand for cataract surgery.

Comparison of visual outcomes in adult patients with different types of developmental cataracts after toric multifocal intraocular lenses implantation

PURPOSE

 To analyze and compare the visual performance and patient satisfaction following the implantation of toric multifocal intraocular lenses (TMIOLs) in adult patients with different types of developmental cataracts (DC) accompanied by corneal astigmatism (CA).

METHODS

 This is a prospective observational cohort study. Patients diagnosed with DC aged 18-30 years were divided into three groups according to the anatomic location of the lens opacity: cortical, nuclear, and posterior subcapsular (PSC) groups, and implanted with TMIOLs. Visual acuity (VA), postoperative refractive astigmatism (RA), intraocular lens (IOL) rotation, high-order aberrations (HOAs), modulation transfer function (MTF) curve, and Strehl ratio were compared. The functional vision and incidence of photic phenomena were surveyed using questionnaires.

RESULTS

 Fifty-five eyes of 37 patients were enrolled and completed a 1-year follow-up. The mean CA was 2.06 ± 0.79 D preoperatively, and the mean RA was 0.29 ± 0.30 D 3-month postoperatively. The IOL rotation was 2.48° ± 1.89°, with no deviation > 10°. At 12 months, mean uncorrected distance VA improved from 0.93 ± 0.41 preoperatively to 0.08 ± 0.08 logarithm of the minimum angle of resolution (logMAR), mean uncorrected near VA increased from 0.45 ± 0.30 preoperatively to 0.12 ± 0.11 logMAR, and mean uncorrected intermediate VA was 0.14 ± 0.08 logMAR. The cortical and nuclear groups displayed better improvements in uncorrected near and intermediate VA than that in the PSC group. Similar results were observed in the 3-month defocus curves, HOAs, MTF curve, halo incidence, and near vision satisfaction.

CONCLUSION

In adult patients with DC accompanied by CA, TMIOLs implantation achieved good postoperative visual outcomes and significantly reduced glasses dependency. Patients with cortical or nuclear lens opacity showed better whole-course VA and quality of vision, while patients with PSC opacity showed unsatisfactory near vision and suffered more photic phenomena.

The development of oscillatory and aperiodic resting state activity is linked to a sensitive period in humans

Congenital blindness leads to profound changes in electroencephalographic (EEG) resting state activity. A well-known consequence of congenital blindness in humans is the reduction of alpha activity which seems to go together with increased gamma activity during rest. These results have been interpreted as indicating a higher excitatory/inhibitory (E/I) ratio in visual cortex compared to normally sighted controls. Yet it is unknown whether the spectral profile of EEG during rest would recover if sight were restored. To test this question, the present study evaluated periodic and aperiodic components of the EEG resting state power spectrum. Previous research has linked the aperiodic components, which exhibit a power-law distribution and are operationalized as a linear fit of the spectrum in log-log space, to cortical E/I ratio. Moreover, by correcting for the aperiodic components from the power spectrum, a more valid estimate of the periodic activity is possible. Here we analyzed resting state EEG activity from two studies involving (1) 27 permanently congenitally blind adults (CB) and 27 age-matched normally sighted controls (MCB); (2) 38 individuals with reversed blindness due to bilateral, dense, congenital cataracts (CC) and 77 age-matched sighted controls (MCC). Based on a data driven approach, aperiodic components of the spectra were extracted for the low frequency (Lf-Slope 1.5 to 19.5 Hz) and high frequency (Hf-Slope 20 to 45 Hz) range. The Lf-Slope of the aperiodic component was significantly steeper (more negative slope), and the Hf-Slope of the aperiodic component was significantly flatter (less negative slope) in CB and CC participants compared to the typically sighted controls. Alpha power was significantly reduced, and gamma power was higher in the CB and the CC groups. These results suggest a sensitive period for the typical development of the spectral profile during rest and thus likely an irreversible change in the E/I ratio in visual cortex due to congenital blindness. We speculate that these changes are a consequence of impaired inhibitory circuits and imbalanced feedforward and feedback processing in early visual areas of individuals with a history of congenital blindness.

Newer insights into the clinical profile of posterior lenticonus in children and its surgical, visual, refractive outcomes

PURPOSE

To analyze the clinical profile of patients with posterior lenticonus and their surgical, visual, and refractive outcomes.

RESULTS

Retrospective interventional case series of 84 eyes of 63 patients with posterior lenticonus. The incidence of posterior lenticonus was 3.98% during a study period of 5 years. One-third of cases had bilateral posterior lenticonus. The mean age was 4.78 ± 4.28 years (unilateral cases were significantly older than bilateral, P = 0.0001). Males were 54%. Mean axial length and keratometry were 21.49 mm and 44.88 D, respectively. Eyes with the bilateral disease were significantly shorter (axial length, P = 0.0012) and smaller (horizontal corneal diameter, P < 0.0001) compared to those with unilateral disease. While 88% were pseudophakic; 12% were aphakic. The posterior capsular defect was noted intraoperatively in 44%. Sixty-eight percent of eyes had a pre-operative diagnosis of posterior lenticonus, 32% were diagnosed intraoperatively. The mean follow-up period was 1.3 years. Best-corrected visual acuity (BCVA) at 6 months was fair to poor in two-third of patients (median 20/100). The mean ± SD visual acuity (LogMAR) and spherical equivalence for unilateral and bilateral cases were 0.70 ± 0.27, 0.67 ± 0.26D (p = 0.57) and 2.04 ± 2.74, 5.15 ± 3.73D (p = 0.0001), respectively. Visual outcomes were better in children who are aged 2 years or more (P = 0.0056). Eight percent needed a second surgery.

CONCLUSION

We report a higher prevalence of bilateral posterior lenticonus in this cohort. The clinical profile of bilateral disease differs from unilateral disease. The diagnosis is not always clinical. In the bag, intra-ocular lens (IOL) implantation is possible in the majority. The visual outcomes remain fair to poor, possibly due to late presentation and the presence of dense refractory amblyopia.

SYNOPSIS

The manuscript consists of the largest series of posterior lenticonus to date. It provides the prevalence of posterior lenticonus along with characteristics difference between unilateral and bilateral cases of posterior lenticonus. Newer insights in terms of diagnostics, pre-operative pick-up rate, how to improve, visual and refractive outcomes of unilateral and bilateral cases are described.

Genetic Analysis in a Swiss Cohort of Bilateral Congenital Cataract

Importance

Identification of geographic population-based differences in genotype and phenotype heterogeneity are important for targeted and patient-specific diagnosis and treatment, counseling, and screening strategies.

Objective

To report disease-causing variants and their detailed phenotype in patients with bilateral congenital cataract from a single center in Switzerland and thereby draw a genetic map and perform a genotype-phenotype comparison of this cohort.

Design, Setting, and Participants

This clinical and molecular-genetic cohort study took place through the collaboration of the Department of Ophthalmology at the University Hospital Zurich and the Institute of Medical Molecular Genetics, University of Zurich, Schlieren, Switzerland. Thirty-seven patients from 25 families with different types of bilateral congenital cataract were included. All participating family members received a comprehensive eye examination. Whole exome sequencing was performed in the index patients, followed by a filtering process to detect possible disease-associated variants in genes previously described in association with congenital cataract. Probable disease-causing variants were confirmed by Sanger sequencing in available family members. All data were collected from January 2018 to June 2020, and the molecular-genetic analyses were performed from January 2019 to July 2020.

Main Outcomes and Measures

Identification of the underlying genetic causes of bilateral congenital cataract, including novel disease-causing variants and phenotype correlation.

Results

Among the 37 patients (18 [49%] male and 19 [51%] female; mean [SD] age, 17.3 [15.9] years) from 25 families, pathogenic variants were detected in 20 families (80% detection rate), which included 13 novel variants in the following genes: BCOR, COL4A1, CRYBA2, CRYBB2, CRYGC, CRYGS, GJA3, MAF, NHS, and WFS1. Putative disease-causing variants were identified in 14 of 20 families (70%) as isolated cases and in 6 of 20 families (30%) with syndromic cases. A recessive variant in the CRYBB2 gene in a consanguineous family with 2 affected siblings showing a nuclear and sutural cataract was reported in contrast to previously published reports. In addition, the effect on splicing in a minigene assay of a novel splice site variant in the NHS gene (c.[719-2A>G]) supported the pathogenicity of this variant.

Conclusions and Relevance

This study emphasizes the importance of genetic testing of congenital cataracts. Known dominant genes need to be considered for recessive inheritance patterns. Syndromic types of cataract may be underdiagnosed in patients with mild systemic features.

A mutated CRYGD associated with congenital coralliform cataracts in two Chinese pedigrees

AIM

To investigate the causal gene mutation and clinical characteristics for two Chinese families with autosomal dominant congenital coralliform cataract.

METHODS

Two Chinese pedigrees with congenital cataract were investigated. Routine ophthalmic examinations were performed on all patients and non-affected family members. Peripheral blood samples were collected, and the genomic DNAs were extracted. The coding regions of proband's DNAs were analyzed with cataract gene panel. The identified mutation was amplified by polymerase chain reaction, and automated sequencing was performed in other members of two families to verify whether the mutated gene was co-segregated with the disease.

RESULTS

Congenital coralliform cataract was inherited in an autosomal dominant mode in both pedigrees. For each family, more than half of the family members were affected. All patients presented with severe visual impairment after birth as a result of bilateral symmetric coralliform lens opacification. An exact the same defect in the same gene, a heterozygous mutation of c.70C>A (p. P24T) in exon 2 of γD-crystallin gene, was detected in both probands from each family. Sanger sequencing analysis demonstrated that the mutated CRYGD was co-segregated in these two families.

CONCLUSION

A c.70C>A (p. P24T) variant in CRYGD gene was reconfirmed to be the causal gene in two Chinese pedigrees. It is known that mutated CRYGD caused most of the congenital coralliform cataracts, suggesting that the CRYGD gene is associated with coralliform congenital cataract.

Congenital cataract - clinical and morphological aspects

Congenital cataract is one of the main causes of blindness in newborns and children. According to the World Health Organization (WHO), there are about 14 million children suffering from congenital cataract. Our study is based on 82 children, males – 46 (56.1%) and females – 36 (43.9%), with congenital cataract operated in the same ophthalmological centre in Bucharest, Romania. Of the 82 patients, 49 (59.76%) had bilateral cataract and 33 (40.24%) unilateral cataract. Clinically, the most frequent was the total cataract, followed by lamellar, nuclear and cerulean. We employed nine surgical approaches in our patients, depending on the type of intraocular lens (IOL). Morphologically, obvious changes were rendered evident at the level of anterior and posterior capsules, as well as subcapsular.

Profile of congenital cataract in the first year of life from a tertiary care center in South India - A modern series

Purpose:

To report the etiology, clinical presentation, and morphology of congenital cataract in a tertiary care center.

Methods:

It is a prospective cohort study conducted at L V Prasad Eye Institute, Hyderabad. All children with congenital cataract ≤ 12 months of age that required surgical intervention between August 2015 and July 2016 were included in the study. 109 such patients were subjected to meticulous history taking, pedigree charting, ocular, and systemic examination, B-scan, TORCH testing, clinical photographs, pediatrician consult and blood tests, which included serum calcium, serum phosphorous and urine for reducing sugars.

Results:

The mean age of presentation was 4.1 months (±2.6 months) and both the genders were equally affected (P = 0.49). Eighty-five patients (77.9%) presented with bilateral cataracts while 24 patients had a unilateral presentation (22.1%). The common morphological presentation was either a total or a nuclear cataract, both variants noticed in 47 patients (43.1%). TORCH infections were responsible for a maximum (37 patients, 33.4%) number of cases followed by familial (20 patients, 18%) and developmental anomalies (11 patients, 10.1%) while the total number of idiopathic cases were 24% (27 patients). Eighteen patients (16.5%) had congenital heart defects and the majority (16 patients, 88.9%) of these had positive TORCH titres.

Conclusion:

Familial cataract and those possibly due to TORCH are still the predominant cause of congenital cataract in this series-highlighting the role of vaccination and preventive measures.

Molecular and Genetic Mechanism of Non-Syndromic Congenital Cataracts. Mutation Screening in Spanish Families

Our purpose was to identify mutations responsible for non-syndromic congenital cataracts through the implementation of next-generation sequencing (NGS) in our center. A sample of peripheral blood was obtained from probands and willing family members and genomic DNA was extracted from leukocytes. DNA was analyzed implementing a panel (OFTv2.1) including 39 known congenital cataracts disease genes. 62 probands from 51 families were recruited. Pathogenic or likely pathogenic variants were identified in 32 patients and 25 families; in 16 families (64%) these were de novo mutations. The mutation detection rate was 49%. Almost all reported mutations were autosomal dominant. Mutations in crystallin genes were found in 30% of the probands. Mutations in membrane proteins were detected in seven families (two in GJA3 and five in GJA8). Mutations in LIM2 and MIP were each found in three families. Other mutations detected affected EPHA2, PAX6, HSF4 and PITX3. Variants classified as of unknown significance were found in 5 families (9.8%), affecting CRYBB3, LIM2, EPHA2, ABCB6 and TDRD7. Mutations lead to different cataract phenotypes within the same family.

Outcome of cataract surgery in children affected by malignancies other than retinoblastoma with eye-lens radiation exposure

PURPOSE

To describe, retrospectively, the visual outcome, feasibility, and safety of cataract surgery in a pediatric population affected by iatrogenic cataract, secondary to systemic oncological treatment for malignancies other than retinoblastoma.

METHODS

Young patients, affected by radiation-induced cataract, who were referred to the San Paolo Ophthalmic Center in Padova between 2010 and 2017, were included in the study. All patients had previously received radiotherapy and/or chemotherapy treatment for malignancies, between 2004 and 2013. All medical records of infants who underwent cataract surgery were accurately reviewed.

RESULTS

Eighteen eyes out of 11 patients included in the study underwent cataract surgery. The mean age at surgery was 9.7 ± 3.6 years. The interval between tumor diagnosis and cataract development was around 3 years. Mean follow-up after surgery was 15.4 ± 6.3 months. All eyes underwent posterior chamber intraocular lens implantation, posterior capsulotomy, and anterior vitrectomy in one time surgery. No intraoperative complications were shown. Post-operatively, only one eye received laser capsulotomy due to posterior capsule opacification. At the end of follow up, best-corrected visual acuity was 20/20 (LogMAR 0) in all eyes and significantly improved (p < 0.01) compared to baseline.

CONCLUSIONS

Iatrogenic-cataract surgery in pediatric oncological patients is a safe and effective way to improve visual acuity. Posterior capsulotomy and anterior vitrectomy at the time of surgery reduce the rate of posterior lens opacification and guarantee an excellent visual acuity in these patients.

Automatic classification of heterogeneous slit-illumination images using an ensemble of cost-sensitive convolutional neural networks

Background

Lens opacity seriously affects the visual development of infants. Slit-illumination images play an irreplaceable role in lens opacity detection; however, these images exhibited varied phenotypes with severe heterogeneity and complexity, particularly among pediatric cataracts. Therefore, it is urgently needed to explore an effective computer-aided method to automatically diagnose heterogeneous lens opacity and to provide appropriate treatment recommendations in a timely manner.

Methods

We integrated three different deep learning networks and a cost-sensitive method into an ensemble learning architecture, and then proposed an effective model called CCNN-Ensemble [ensemble of cost-sensitive convolutional neural networks (CNNs)] for automatic lens opacity detection. A total of 470 slit-illumination images of pediatric cataracts were used for training and comparison between the CCNN-Ensemble model and conventional methods. Finally, we used two external datasets (132 independent test images and 79 Internet-based images) to further evaluate the model's generalizability and effectiveness.

Results

Experimental results and comparative analyses demonstrated that the proposed method was superior to conventional approaches and provided clinically meaningful performance in terms of three grading indices of lens opacity: area (specificity and sensitivity; 92.00% and 92.31%), density (93.85% and 91.43%) and opacity location (95.25% and 89.29%). Furthermore, the comparable performance on the independent testing dataset and the internet-based images verified the effectiveness and generalizability of the model. Finally, we developed and implemented a website-based automatic diagnosis software for pediatric cataract grading diagnosis in ophthalmology clinics.

Conclusions

The CCNN-Ensemble method demonstrates higher specificity and sensitivity than conventional methods on multi-source datasets. This study provides a practical strategy for heterogeneous lens opacity diagnosis and has the potential to be applied to the analysis of other medical images.

Clinical profile and surgical outcomes in children with posterior lenticonus

AIMS:

The purpose of this study is to describe the clinical profile of children presenting with posterior lenticonus. We also report on visual outcomes following surgery in these patients.

SUBJECTS AND METHODS:

Medical records of patients with a diagnosis of posterior lenticonus between January 2000 and December 2016 were reviewed. Data collected included demographic details, preoperative, intraoperative details like type of intraocular lens (IOL) and surgery, and amblyopia therapy. Only the patients with a follow-up of at least 6 months from the time of presentation were included in the analysis.

RESULTS:

Forty-eight eyes with posterior lenticonus with at least 6 months of follow-up were studied. Twelve (25%) eyes had a preoperative posterior capsule (PC) dehiscence as seen on slit-lamp biomicroscopy or on ultrasonography. The mean presenting visual acuity in all eyes was 1.034 ± 0.56 logarithm of the minimum angle of resolution (logMAR) units. The mean final visual acuity in these patients was 0.57 ± 0.5 logMAR units. Postoperative visual acuity was found to have a borderline positive correlation with the presence of preoperative strabismus (P = 0.049). Younger age at presentation (P = 0.533) or the presence of preoperative PC dehiscence (P = 0.735) did not influence final visual acuity.

CONCLUSION:

Visual acuity improves following surgery with IOL implantation in children with posterior lenticonus and cataract. With the availability of foldable lenses and improved surgical techniques, it is possible to place the IOL in bag despite a preexisting posterior capsular dehiscence. Children with posterior lenticonus who present with strabismus are likely to have poorer visual outcomes.

Visual outcomes of surgical and conservative treatment in children with small posterior polar cataracts and posterior lenticonus

AIM

To compare the visual outcomes of children with small (≤3 mm) posterior polar cataracts (PPC) and posterior lenticonus who had cataract extraction surgery with the visual outcomes of those who were managed conservatively.

METHODS

Children who initially had small PPC and posterior lenticonus who were followed up over 1-year period were retrospective reviewed in the study. Patients receiving surgery were compared with those receiving conservative therapy. The axial length, keratometry, refraction, best-corrected visual acuity (BCVA), and strabismus measurements were recorded. Lens morphology, i.e., the location, size, and depth of the cataract lesion, was measured with a Scheimpflug imaging system. To help control for baseline differences in the groups, patients were matched with controls by propensity score methodology.

RESULTS

The study evaluated 60 patients (30 in the surgery group and 30 in the conservative therapy group) after matching by propensity score. Patients who underwent cataract surgery showed greater BCVA improvements (0.36±0.24 logMAR) than patients who were treated without surgery (0.22±0.26 logMAR; P=0.036). Surgery was effective in patients with a rear projection length (RPL) less than 1.0 mm and a pretreatment BCVA worse than 0.52 logMAR.

CONCLUSION

Children with small PPC and posterior lenticonus who undergo cataract surgery experience greater BCVA improvements than those managed conservatively. Certain patients presenting with a RPL less than 1.0 mm and a pretreatment BCVA of 0.52 logMAR or worse may benefit from surgery.

Analysis of corneal astigmatism and aberration in chinese congenital cataract and developmental cataract patients before cataract surgery

BACKGROUND

To investigate the distribution of corneal astigmatism, aberration, and biometric parameters in Chinese congenital cataract (CC) /developmental cataract patients before cataract surgery.

METHODS

We evaluated eyes of CC /developmental cataract patients scheduled for cataract surgery from January 2016 to September 2019. Astigmatism, aberrations, and biometric parameters were measured with the Pentacam Scheimpflug imaging device (Pentacam HR, Oculus). Cataract was diagnosed and classified by slit-lamp examination after full mydriasis.

RESULTS

We evaluated 538 eyes in 356 patients. The mean values of anterior corneal astigmatism (ACA), posterior corneal astigmatism (PCA), and total corneal astigmatism (TCA) were determined as 1.98 ± 1.06 D (range 0.0‒4.8 D), 0.49 ± 0.26 D (range 0.0‒1.9 D), and 2.09 ± 1.19 D (range 0.2‒8.8 D), respectively. ACA and TCA ≥ 1.25 D was present in 379 eyes (70.3%) and 392 eyes (72.8%), respectively. PCA between 0.25 D and 0.75 D was found in 380 eyes (70.6%). There was a statistically significant positive linear correlation between lower-order aberrations root mean square values (LOA RMS) and corneal astigmatism (CA). Furthermore, in terms of distribution of central cornea thickness, anterior chamber depth, ACA, PCA, and TCA in different types of cataracts, ACA was highest in patients with zonular cataracts. Finally, we found anterior corneal measurements may overestimate WTR astigmatism, underestimate ATR astigmatism, and underestimate oblique astigmatism, respectively.

CONCLUSIONS

Most CC /developmental cataract patients had moderate to high astigmatism and ACA accounted for the largest proportion in the zonular group. This can provide a basis for planning of CC/developmental cataract surgery by ophthalmologists in clinical practice.

Application of machine learning in ophthalmic imaging modalities

In clinical ophthalmology, a variety of image-related diagnostic techniques have begun to offer unprecedented insights into eye diseases based on morphological datasets with millions of data points. Artificial intelligence (AI), inspired by the human multilayered neuronal system, has shown astonishing success within some visual and auditory recognition tasks. In these tasks, AI can analyze digital data in a comprehensive, rapid and non-invasive manner. Bioinformatics has become a focus particularly in the field of medical imaging, where it is driven by enhanced computing power and cloud storage, as well as utilization of novel algorithms and generation of data in massive quantities. Machine learning (ML) is an important branch in the field of AI. The overall potential of ML to automatically pinpoint, identify and grade pathological features in ocular diseases will empower ophthalmologists to provide high-quality diagnosis and facilitate personalized health care in the near future. This review offers perspectives on the origin, development, and applications of ML technology, particularly regarding its applications in ophthalmic imaging modalities.

Causes of delayed presentation of pediatric cataract: A questionnaire-based prospective study at a tertiary eye care center in central rural India

Purpose

To find out the sociodemographic, sociocultural, and socioeconomic factors leading to delay in pediatric cataract surgery and its impact on final visual outcome.

Methods

A prospective interview-based analytical cohort study was conducted on 156 children aged 0-16 years with either unilateral or bilateral congenital/developmental cataracts. Caregivers were interviewed using a pretested validated questionnaire. Time intervals between recognition by a caregiver to consultation were denoted as Delay-1 and between consultations to surgical intervention as Delay-2. Spearman's rank correlation was used to determine the presence of correlation between causes of delay and visual outcome.

Results

The mean age of presentation was 7.78 ± 4.34 years. Mothers were the first informant of the problem (n = 110, 70.5%). Out of 156 children, only 8 (5.1%) children presented to the hospital within 1 month by caregivers and 26 (16.7%) children underwent surgery within 2 months of advice. About 22 (14.1%) children had total cumulative delay of 1-6 months, 11 (7%) had delay of 6-12 months, and 115 (73.71%) had delay of >12 months. The most common cause identified for Delay-1 was unawareness in 41 cases (26.28%), however, for Delay-2 major factor responsible was cost (n = 38, 24.35%). The median preoperative visual acuity was 1.31 logMAR and median postoperative visual acuity at 4 weeks was 0.61 logMAR. (P < 0.001) Less age at surgery, upper socioeconomic status, less time delay, and better preoperative vision were positively correlated to better visual outcomes.

Conclusion

Delay in presentation for childhood cataract surgery remains a significant problem in central rural India. Delay in surgery is multifactorial which includes unawareness, cost, misdiagnosis, self-treatment, distance from the hospital, lack of family support, and poor socioeconomic status.

Clinical Characteristics and Surgical Safety in Congenital Cataract Eyes with Three Pathological Types of Posterior Capsule Abnormalities

Purpose

To observe the clinical characteristics of 3 pathological types of posterior capsule abnormalities (PCAs) in congenital cataracts (CCs) and evaluate the surgical safety in these eyes.

Methods

This study involved 239 children (367 eyes) with CC who underwent cataract surgery at the Eye Hospital of Wenzhou Medical University. All surgery videos were collected for detailed reviews. Intraoperative and postoperative complications (within 3 months) were all recorded.

Results

The 3 pathological types of PCAs, namely, persistent fetal vasculature (PFV), posterior capsule defect (PCD), and posterior lenticonus (PLC), presented in 129 (35.1%) CC eyes, while 238 (64.9%) eyes were recorded as CC without PCA. The percentages of PFV, PCD, and PLC were 10.9%, 26.7%, and 5.4% in CC eyes (n = 367), respectively. The most common concomitant of PFV eyes was PCD (42.5%), and PFV was the most frequent (17.3%) one in PCD eyes. PLC was only associated with PFV (15%) and PCD (50%). The occurrence rates of surgical complications ranged from 0 to 5.4%, and no statistical difference was found between the eyes with and without PCA (all P > 0.05).

Conclusions

PFV, PCD, and PLC play a very important role in the CCs. The effect of fetal vessels in PFV eyes might be an abnormally strong attachment on the posterior capsule, leading to PLC and PCD. Even in PCA patients, severe surgical complication can also be avoided with well-designed and skilled operation. This trial is registered with NCT03905044 at http://ClinicalTrials.gov.

A broad range of symptoms in allgrove syndrome: single center experience in Southeast Anatolia

BACKGROUND

Allgrove syndrome (OMIM 231550) is a rare autosomal recessive disease characterized by non-CAH primary adrenal insufficiency (non-CAH PAI), alacrima, and achalasia. It is caused by mutations in the AAAS gene. The syndrome is also associated with variable progressive neurological impairment and dermatological abnormalities.

METHODS AND RESULTS

We diagnosed 23 patients from 14 families with Allgrove syndrome, based on the presence of at least two characteristic symptoms, usually adrenal insufficiency and alacrima, between 2008 and 2018. A previously described nonsense variant of AAAS was detected in 19 patients from 12 families at homozygous state. Another novel homozygous mutation (c.394-397delCTGT) in AAAS was detected in four patients from two families. Presenting symptoms were alacrima (23/23; 100%), adrenal insufficiency (18/23; 78%), achalasia (13/23; 57%), short stature/growth retardation (16/23; 70%), hyperreflexia (15/23; 65%), palmoplantar hyperkeratosis (13/23; 57%), hyperpigmentation of the skin (10/23; 43%), hypoglycemia-induced convulsion (7/23; 30%), swallowing difficulty and vomiting (6/23; 26%). Serum DHEAS concentrations were low in all patients (23/23; 100%).

CONCLUSIONS

Clinical symptoms vary even among patients carrying the same mutation. Triple A syndrome should be considered in the etiology of non-CAH PAI in Arab populations and in Southeast Turkey. Any child with non-CAH PAI should be evaluated for the presence of alacrima and/or achalasia or family history of alacrima and/or achalasia. Children with alacrima and/or achalasia should also be investigated for adrenal insufficiency. Definitive molecular diagnosis is essential for early diagnosis and management of adrenal insufficiency, neurological symptoms, and growth retardation in patients and early diagnosis of as yet asymptomatic cases in the family, together with genetic counseling.

Inter-regional trends in causes of childhood blindness and low vision in Ghana

BACKGROUND

Inter-regional trends of visual loss in most developing countries remain largely unknown. We compared the causes of childhood blindness among children attending blind schools in the northern (one school) and southern (two schools) regions of Ghana and assessed their need for spectacles and low-vision devices.

METHODS

Using a standardised methodology, children were examined by an ophthalmologist and optometrists in each location. Causes of visual loss were classified anatomically and by time of onset, and avoidable causes identified. Children identified with functional low vision were assessed and provided with low-vision devices.

RESULTS

A total of 252 children under 16 years of age were examined in the schools. The overall prevalence of total blindness was 73 (29.0 per cent), with similar proportions (p = 0.87) in the north (29 [28.4 per cent]) and south (44 [29.3 per cent]); 92 (36.5 per cent) had functional low vision. Two children improved with spectacles and 35 benefited from low-vision devices. Corneal scarring was significantly (p = 0.045) more prevalent in southern Ghana (n = 150) than in the north (n = 102), responsible for visual loss in 36 (24.0 per cent, 95% CI 17.2-30.8 per cent) and 14 (13.7 per cent, 95% CI 7.0-20.4 per cent) cases, respectively. No significant difference (p = 0.321) was observed in the prevalence of cataract between northern (28: 27.5 per cent, 95% CI 18.3-36.2 per cent) and southern Ghana (33: 22.0 per cent, 95% CI 15.4-28.6 per cent). Over 87 per cent of children had 'avoidable' causes of visual loss, with a higher proportion being treatable (124: 49.2 per cent) than preventable (96: 38 per cent).

CONCLUSION

Cataract was the major cause of visual loss in the overall population. The south had a higher proportion of corneal scarring and late-onset blindness compared with the north. More than one-third of blindness in blind schools in Ghana could have been prevented by primary care interventions and nearly half could have been treated surgically to prevent visual loss. Two in five children in blind schools in Ghana could benefit from optical intervention.

Posterior Capsule Opacification after Cataract Surgery in Children Over Five Years of Age with Square-edge Hydrophobic versus Hydrophilic Acrylic Intraocular Lenses: A Prospective Randomized Study

OBJECTIVE

To compare the effects of hydrophobic and hydrophilic materials in square-edged acrylic intraocular lenses (IOLs) on the development of posterior capsule opacification (PCO) after pediatric cataract surgery.

METHODS

Patients were randomly assigned to group 1 (hydrophobic acrylic square-edged IOLs; 13 eyes) or group 2 (hydrophilic acrylic square-edged IOLs; 13 eyes). The study evaluated PCO rates using Evaluation of Posterior Capsule Opacification (EPCO) 2000 software at one, three, six and 12 months postoperatively. Postoperative measurements also included corrected distance visual acuity (CDVA), neodymium:yttrium-aluminum-garnet (Nd:YAG) capsulotomy and postoperative complications other than PCO.

RESULTS

Both groups had significant increases in PCO rates after one year. Comparison of the groups showed no significant differences in the EPCO scores at three (group 1, 0.007±0.016 vs group 2, 0.008±0.014; p=0.830), six (group 1, 0.062±0.103 vs group 2, 0.021±0.023; p=0.184), or twelve months postoperatively (group 1, 0.200±0.193 vs group 2, 0.192±0.138; p=0.902). We also found no significant group differences regarding the change (delta, Δ) in EPCO scores between three and six months (group 1, 0.055±0.09 vs group 2, 0.013±0.02; p=0.113) or between six and twelve months postoperatively (group 1, 0.139±0.14 vs group 2, 0.171±0.14; p=0.567). Twenty-three percent of patients required Nd:YAG capsulotomy at the twelve-month visit.

CONCLUSIONS

No differences in PCO rates were found between hydrophobic and hydrophilic acrylic square-edged IOLs in children between five and twelve years of age at one year of follow-up.

Biology of Inherited Cataracts and Opportunities for Treatment

Cataract, the clinical correlate of opacity or light scattering in the eye lens, is usually caused by the presence of high-molecular-weight (HMW) protein aggregates or disruption of the lens microarchitecture. In general, genes involved in inherited cataracts reflect important processes and pathways in the lens including lens crystallins, connexins, growth factors, membrane proteins, intermediate filament proteins, and chaperones. Usually, mutations causing severe damage to proteins cause congenital cataracts, while milder variants increasing susceptibility to environmental insults are associated with age-related cataracts. These may have different pathogenic mechanisms: Congenital cataracts induce the unfolded protein response and apoptosis. By contrast, denatured crystallins in age-related cataracts are bound by α-crystallin and form light-scattering HMW aggregates. New therapeutic approaches to age-related cataracts use chemical chaperones to solubilize HMW aggregates, while attempts are being made to regenerate lenses using endogenous stem cells to treat congenital cataracts.

Under-utilisation of reproducible, child appropriate or patient reported outcome measures in childhood uveitis interventional research

Background

Childhood uveitis is a collection of chronic rare inflammatory eye disorders which result in visual loss in at least one eye of one fifth of affected children. Despite the introduction of novel systemic immunochemotherapies, it remains a blinding disease.

We have undertaken a systematic review of outcome measures used in interventional trials of children with, or at risk of uveitis, in order to investigate metric quality and heterogeneity, as possible barriers to the translation of clinical research into improved outcomes.

Methods

Systematic review of trials registered within databases approved by the International Committee of Medical Journal Editors (ICMJE). Eligible trials for were those which involved participants aged under 18 years with or at risk of non-infectious uveitis. Data on date of study commencement, uveitis site, inclusion age criteria, and outcome measure characteristics including type, dimension and quality were extracted independently by two authors. Quality was determined using the reproducibility, validity and age-appropriateness of the metric.

Results

Of 917 identified trials, 57 were eligible for inclusion. Twenty different domains across five dimensions were used as primary outcome measures. The structure most commonly used was multiple separate outcome measures. In a quarter of studies, outcomes were assessed less than 3 months following the intervention. Disease activity was the most commonly assessed dimension, with only 30 studies (60%) using reproducible methodologies to assess activity. Only 2/12 (18%) studies on intermediate or posterior uveitis used reproducible activity grading schemes. Of 18 studies involving children aged under 6 years old which used outcome measures related to visual function, only 8/18 (44%) described the use of age-appropriate acuity assessment measures. None of the studies used a vision related quality of life metrics which had been validated for use in childhood.

Conclusion

This review of outcome measures in childhood uveitis interventional trials has identified under-utilisation of reproducible or child appropriate measures, and considerable heterogeneity in metric type, and structure. Clinicians and researchers interested in improving outcomes for affected children must identify a patient and family centred core outcome set, and work to validate both objective and patient (or proxy) reported disease age appropriate outcome measures.

Electronic supplementary material

The online version of this article (10.1186/s13023-019-1108-3) contains supplementary material, which is available to authorized users.

Factors influencing myopic shift in children after intraocular lens implantation

Introduction:

Intraocular lenses have always been a controversial topic in pediatric cataract surgery. In the early 1990s in the post-Soviet states of Eastern Europe, intraocular lenses promised an easier full-time correction and amblyopia treatment. Since 1991, ophthalmologists in Latvia have been implanting intraocular lenses in infants. Amount of the postoperative myopic shift and its influencing factors, analyzed in this article, are important indicators of congenital cataract treatment.

Materials and methods:

A retrospective chart review off 85 children (137 eyes) who underwent foldable posterior chamber intraocular lens implantation at the Clinical University Hospital in Riga, Latvia, from 1 January 2006 until 31 December 2016, was performed. Depending on the age at surgery, patients were divided into six groups: 1–6, 7–12, 13–24, 25–48, 49–84, and 85–216 months.

Results:

The largest and more variable myopic shift was found in a group of diffuse/total and nuclear cataract with surgery before the age of 6 months. There was a statistically significant correlation between the acquired best-corrected visual acuity and the amount of myopic shift (rs = 0.33; p < 0.001). Comparing the amount of myopic shift in two groups of different intraocular lens implantation target refraction tactics, we did not find statistically significant differences. Comparing the amount of myopic shift and implanted intraocular lens power, a negative, statistically significant correlation was found.

Conclusion:

The earlier the cataract extraction surgery and intraocular lens implantation is performed, the larger the myopic shift. The morphological type of cataract, best-corrected visual acuity, secondary glaucoma, and intraocular lens power influence the amount of myopic shift.

Steroid Induced Cataract in Langerhans Cell Histiocytosis Patient

BACKGROUND:

Cataract is an opacification of the lens. Pediatric cataracts can be congenital or acquired. Acquired cataract including the one caused by corticosteroid used. It occurred as bilateral posterior subcapsular cataracts and tended to be progressive. Treatment of choice is lens extraction with or without intraocular lens (IOL).

CASE PRESENTATION:

We present a case of posterior subcapsular cataract that occurs in a patient with Langerhans cell histiocytosis that was using corticosteroid therapy.

CONCLUSION:

The routine ophthalmologic examination should be performed in children who received treatment with corticosteroids in the long term so that with early detection it can be given early treatment.

Cortical riders of zonular cataracts as "reverse cuneiform" cataracts: A hypothesis

Zonular cataracts are childhood cataracts involving one or more zone(s) of lens. They often show 'riders' which are wedge-shaped opacifications of inner cortex of the lens seen to radiate towards the lens equator, though little is known about the exact mechanism behind their development. Cortical riders may be described as 'reverse cuneiform' cataracts on the basis of their evolution pattern being exact opposite to that of senile cuneiform cortical cataracts.

Pediatric cataract

Pediatric cataract is a leading cause of childhood blindness. Untreated cataracts in children lead to tremendous social, economical, and emotional burden to the child, family, and society. Blindness related to pediatric cataract can be treated with early identification and appropriate management. Most cases are diagnosed on routine screening whereas some may be diagnosed after the parents have noticed leukocoria or strabismus. Etiology of pediatric cataract is varied and diagnosis of specific etiology aids in prognostication and effective management. Pediatric cataract surgery has evolved over years, and with improving knowledge of myopic shift and axial length growth, outcomes of these patients have become more predictable. Favorable outcomes depend not only on effective surgery, but also on meticulous postoperative care and visual rehabilitation. Hence, it is the combined effort of parents, surgeons, anesthesiologists, pediatricians, and optometrists that can make all the difference.

Monitoring and Morphologic Classification of Pediatric Cataract Using Slit-Lamp-Adapted Photography

Purpose

To investigate the feasibility of pediatric cataract monitoring and morphologic classification using slit lamp–adapted anterior segmental photography in a large cohort that included uncooperative children.

Methods

Patients registered in the Childhood Cataract Program of the Chinese Ministry of Health were prospectively selected. Eligible patients underwent slit-lamp adapted anterior segmental photography to record and monitor the morphology of their cataractous lenses. A set of assistance techniques for slit lamp–adapted photography was developed to instruct the parents of uncooperative children how to help maintain the child's head position and keep the eyes open after sleep aid administration.

Results

Briefly, slit lamp–adapted photography was completed for all 438 children, including 260 (59.4%) uncooperative children with our assistance techniques. All 746 images of 438 patients successfully confirmed the diagnoses and classifications. Considering the lesion location, pediatric cataract morphologies could be objectively classified into the seven following types: total; nuclear; polar, including two subtypes (anterior and posterior); lamellar; nuclear combined with cortical, including three subtypes (coral-like, dust-like, and blue-dot); cortical; and Y suture. The top three types of unilateral cataracts were polar (55, 42.3%), total (42, 32.3%), and nuclear (23, 17.7%); and the top three types of bilateral cataracts were nuclear (110, 35.8%), total (102, 33.2%), and lamellar (34, 11.1%).

Conclusions

Slit lamp–adapted anterior segmental photography is applicable for monitoring and classifying the morphologies of pediatric cataracts and is even safe and feasible for uncooperative children with assistance techniques and sleep aid administration.

Translational Relevance

This study proposes a novel strategy for the preoperative evaluation and evidence-based management of pediatric ophthalmology (Clinical Trials.gov, NCT02748031).

Characteristics of Anterior Lens Opacities in Children

BACKGROUND

Anterior lens opacities (ALO) are found in 3-14% of pediatric patients with cataracts. No clear guidelines exist in the management and treatment of these cataracts.

OBJECTIVE

To evaluate pediatric patients with anterior lens opacities and assess rate of amblyopia and need for surgery over time.

METHODS

A retrospective chart review was performed on patients with unilateral and bilateral anterior lens opacities (ALOs) seen between January 2008 and December 2014. Size, location, and type of ALO were noted. Refractive error, necessity for treatment of amblyopia, and interventions were recorded.

RESULTS

A total of 31 patients were included in the study. 17 patients had unilateral ALOs and 14 had bilateral ALOs. The majority of the cataracts (90.3%) were centrally located. The most common type of cataract was the polar type of cataract and the vast majority (48.4%) was < 1mm in size. 38.7% of patients had concurrent ocular conditions and 9.7% had systemic associations. 28.6% of patients with bilateral cataracts and 35.3% of the patients with unilateral cataracts were treated for amblyopia. Three patients required cataract surgery.

CONCLUSION

About half of anterior lens opacities are less than 1mm in size and the majority are of the polar type. Risk of amblyopia in these patients is higher than in the general population. Anisometropia is the most common cause of amblyopia. Ocular associations are seen at a relatively high frequency and systemic associations can occur but are uncommon. The need for surgical intervention is infrequent; however, growth of ALOs and associated cortical changes may be risk factors for surgery.

Localization and diagnosis framework for pediatric cataracts based on slit-lamp images using deep features of a convolutional neural network

Slit-lamp images play an essential role for diagnosis of pediatric cataracts. We present a computer vision-based framework for the automatic localization and diagnosis of slit-lamp images by identifying the lens region of interest (ROI) and employing a deep learning convolutional neural network (CNN). First, three grading degrees for slit-lamp images are proposed in conjunction with three leading ophthalmologists. The lens ROI is located in an automated manner in the original image using two successive applications of Candy detection and the Hough transform, which are cropped, resized to a fixed size and used to form pediatric cataract datasets. These datasets are fed into the CNN to extract high-level features and implement automatic classification and grading. To demonstrate the performance and effectiveness of the deep features extracted in the CNN, we investigate the features combined with support vector machine (SVM) and softmax classifier and compare these with the traditional representative methods. The qualitative and quantitative experimental results demonstrate that our proposed method offers exceptional mean accuracy, sensitivity and specificity: classification (97.07%, 97.28%, and 96.83%) and a three-degree grading area (89.02%, 86.63%, and 90.75%), density (92.68%, 91.05%, and 93.94%) and location (89.28%, 82.70%, and 93.08%). Finally, we developed and deployed a potential automatic diagnostic software for ophthalmologists and patients in clinical applications to implement the validated model.

Molecular Genetics of Cataract

Lens opacities or cataract(s) represent a universally important cause of visual impairment and blindness. Typically, cataract is acquired with aging as a complex disorder involving environmental and genetic risk factors. Cataract may also be inherited with an early onset either in association with other ocular and/or systemic abnormalities or as an isolated lens phenotype. Here we briefly review recent advances in gene discovery for inherited and age-related forms of cataract that are providing new insights into lens development and aging.

Pediatric cataract: challenges and future directions

Cataract is a significant cause of visual disability in the pediatric population worldwide and can significantly impact the neurobiological development of a child. Early diagnosis and prompt surgical intervention is critical to prevent irreversible amblyopia. Thorough ocular evaluation, including the onset, duration, and morphology of a cataract, is essential to determine the timing for surgical intervention. Detailed assessment of the general health of the child, preferably in conjunction with a pediatrician, is helpful to rule out any associated systemic condition. Although pediatric cataracts have a diverse etiology, with the majority being idiopathic, genetic counseling and molecular testing should be undertaken with the help of a genetic counselor and/or geneticist in cases of hereditary cataracts. Advancement in surgical techniques and methods of optical rehabilitation has substantially improved the functional and anatomic outcomes of pediatric cataract surgeries in recent years. However, the phenomenon of refractive growth and the process of emmetropization have continued to puzzle pediatric ophthalmologists and highlight the need for future prospective studies. Posterior capsule opacification and secondary glaucoma are still the major postoperative complications necessitating long-term surveillance in children undergoing cataract surgery early in life. Successful management of pediatric cataracts depends on individualized care and experienced teamwork. We reviewed the etiology, preoperative evaluation including biometry, choice of intraocular lens, surgical techniques, and recent developments in the field of childhood cataract.

Exome sequencing identifies novel and recurrent mutations in GJA8 and CRYGD associated with inherited cataract

BACKGROUND

Inherited cataract is a clinically important and genetically heterogeneous cause of visual impairment. Typically, it presents at an early age with or without other ocular/systemic signs and lacks clear phenotype-genotype correlation rendering both clinical classification and molecular diagnosis challenging. Here we have utilized trio-based whole exome sequencing to discover mutations in candidate genes underlying autosomal dominant cataract segregating in three nuclear families.

RESULTS

In family A, we identified a recurrent heterozygous mutation in exon-2 of the gene encoding γD-crystallin (CRYGD; c.70C > A, p.Pro24Thr) that co-segregated with 'coralliform' lens opacities. Families B and C were found to harbor different novel variants in exon-2 of the gene coding for gap-junction protein α8 (GJA8; c.20T > C, p.Leu7Pro and c.293A > C, p.His98Pro). Each novel variant co-segregated with disease and was predicted in silico to have damaging effects on protein function.

CONCLUSIONS

Exome sequencing facilitates concurrent mutation-profiling of the burgeoning list of candidate genes for inherited cataract, and the results can provide enhanced clinical diagnosis and genetic counseling for affected families.

Mutation of the melastatin-related cation channel, TRPM3, underlies inherited cataract and glaucoma

Inherited forms of cataract are a clinically important and genetically heterogeneous cause of visual impairment that usually present at an early age with or without systemic and/or other ocular abnormalities. Here we have identified a new locus for inherited cataract and high-tension glaucoma with variable anterior segment defects, and characterized an underlying mutation in the gene coding for transient receptor potential cation channel, subfamily M, member-3 (TRPM3, melastatin-2). Genome-wide linkage analysis mapped the ocular disease locus to the pericentric region of human chromosome 9. Whole exome and custom-target next-generation sequencing detected a heterozygous A-to-G transition in exon-3 of TRPM3 that co-segregated with disease. As a consequence of alternative splicing this missense mutation was predicted to result in the substitution of isoleucine-to-methionine at codon 65 (c.195A>G; p.I65 M) of TRPM3 transcript variant 9, and at codon 8 (c.24A>G; p.I8 M) of a novel TRPM3 transcript variant expressed in human lens. In both transcript variants the I-to-M substitution was predicted in silico to exert damaging effects on protein function. Furthermore, transient expression studies of a recombinant TRPM3-GFP reporter product predicted that the I-to-M substitution introduced an alternative translation start-site located 89 codons upstream from the native initiator methionine found in eight other TRPM3 transcript variants (1-8). Collectively, these studies have provided the first evidence that TRPM3 is associated with inherited ocular disease in humans, and further provide support for the important role of this cation channel in normal eye development.

HSF4 mutation p.Arg116His found in age-related cataracts and in normal populations produces childhood lamellar cataract in transgenic mice

The p.Arg116His mutation in the heat shock transcription factor-4 (HSF4) has been associated with age-related cataracts, but it is also seen in 2% of the normal population, indicating either reduced penetrance or that the normal subjects were not old enough to express the phenotype. Based on the proximity of p.Arg116His to two known mutations in the DNA-binding domain of HSF4, namely, p.Leu114Pro and p.Arg119Cys, which segregate with childhood lamellar cataract, we tested the possibility that this phenotype may have been missed by the ophthalmologist and/or that it did not spread to the visual axis so as to affect vision significantly. Here, we demonstrate via BAC (bacterial artificial chromosome) transgenesis that p.Arg116His recreates the childhood lamellar cataract in mice suggesting that incomplete penetrance associated with early cataracts may not be an absence but a limitation of the detection of the phenotype.

Clinical results of 40 years of paediatric keratoplasty in a single university eye clinic

PURPOSE

  To evaluate indications for paediatric keratoplasty in recipients aged ≤16 years and assess long-term clinical outcome.

METHOD

  Recipients were identified from records of the Danish Cornea Bank. Data were collected from patient journals, clinical follow-up examinations and questionnaires and stratified into pre-, peri- and postoperative variables. Diagnoses were classified into acquired traumatic, acquired nontraumatic and congenital groups. Recipients were divided into groups of <8 and ≥8 years. Data were analyzed using relative percentages and Kaplan-Meier survival plots.

RESULTS

  Thirty-three out of sixty identified recipients (73 keratoplasties in 63 eyes) were invited. Twenty-four accepted, seven still attended follow-up in our clinic. Follow-up data reached 95% of the eligible recipients (median follow-up 11 years). Twenty-three per cent were <8 years and 77%≤8 years. Diagnoses were mainly acquired nontraumatic (69%), acquired traumatic (12%) and congenital (7%). Indications were primarily optical (52%) or tectonic (41%). Graft survival was best in the acquired nontraumatic group (except regrafts) (median survival 15-20 years) and poorest in the regraft subgroup as well as the acquired traumatic and congenital groups (median survival 1-2 years). Graft failure was higher in the youngest with predisposing risk factors and in combined procedures. In terms of indications, visual improvement and eye preservation was achieved in 70%.

CONCLUSION

  Paediatric keratoplasty was successful regarding indication. Graft survival was best in the acquired nontraumatic group and poorest in the congenital group. Vascularization and/or combined risk factors, additional surgeries and young recipient age influenced negatively on graft survival.

A nonsense mutation of γD-crystallin associated with congenital nuclear and posterior polar cataract in a Chinese family

OBJECTIVE

The goal of this study was to characterize the disease-causing mutations in a Chinese family with congenital nuclear and posterior polar cataracts.

METHODS

Clinical data of patients in the family were recorded using slit-lamp photography and high definition video. Genomic DNA samples were extracted from the peripheral blood of the pedigree members and 100 healthy controls. Mutation screening was performed in the candidate genes by bi-directional sequencing of the amplified products.

RESULTS

The congenital cataract phenotype of the pedigree was identified by slit-lamp examinations and observation during surgery as nuclear and posterior polar cataracts. Through the sequencing of the candidate genes, a heterozygous c. 418C>T change was detected in the coding region of the γD-crystallin gene (CRYGD). As a result of this change, a highly conserved arginine residue was replaced by a stop codon (p. R140X). This change was discovered among all of the affected individuals with cataracts, but not among the unaffected family members or the 100 ethnically matched controls.

CONCLUSIONS

This study identified a novel congenital nuclear and posterior polar cataract phenotype caused by the recurrent mutation p. R140X in CRYGD.

Surgical outcomes after intraocular lens implantation for posterior lenticonus-related cataract according to preoperative lens status

PURPOSE

To address the surgical outcomes of pediatric patients with cataracts associated with posterior lenticonus who required cataract extraction and intraocular lens (IOL) implantation according to preoperative lens status.

SETTING

Department of Ophthalmology, Seoul National University Children's Hospital, Seoul, South Korea.

DESIGN

Comparative case series.

METHODS

Patients who had cataract extraction and IOL implantation for posterior lenticonus were divided into 2 groups according to the preoperative lens status. Clinical features and visual outcomes in both groups were comparatively analyzed.

RESULTS

Forty-seven eyes of 43 patients were studied. Thirty-five eyes had lens opacities localized to the posterior pole, and 12 eyes presented with total opacity of the lens. Preexisting posterior capsule defect was identified intraoperatively in 11 eyes with total lens opacity. Eyes with preexisting posterior capsule defects more frequently required ciliary sulcus fixation of the IOL (P=.01). The mean follow-up after cataract extraction was 66.9 months ± 35.9 (SD). The mean final corrected distance visual acuity of patients with total opacity (0.37 ± 0.57 logMAR) was better than that of patients with posterior polar opacity (0.56 ± 0.50 logMAR), with borderline significance (P=.05).

CONCLUSIONS

A preexisting posterior capsule defect, found most often in eyes that presented with total lens opacity, could be an obstacle to capsular bag fixation of the IOL. Posterior lenticonus patients with total lens opacity had marginally significantly better visual outcomes than patients with posterior polar opacity.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Structural integrity of the Greek key motif in βγ-crystallins is vital for central eye lens transparency

Background

We highlight an unrecognized physiological role for the Greek key motif, an evolutionarily conserved super-secondary structural topology of the βγ-crystallins. These proteins constitute the bulk of the human eye lens, packed at very high concentrations in a compact, globular, short-range order, generating transparency. Congenital cataract (affecting 400,000 newborns yearly worldwide), associated with 54 mutations in βγ-crystallins, occurs in two major phenotypes nuclear cataract, which blocks the central visual axis, hampering the development of the growing eye and demanding earliest intervention, and the milder peripheral progressive cataract where surgery can wait. In order to understand this phenotypic dichotomy at the molecular level, we have studied the structural and aggregation features of representative mutations.

Methods

Wild type and several representative mutant proteins were cloned, expressed and purified and their secondary and tertiary structural details, as well as structural stability, were compared in solution, using spectroscopy. Their tendencies to aggregate in vitro and in cellulo were also compared. In addition, we analyzed their structural differences by molecular modeling in silico.

Results

Based on their properties, mutants are seen to fall into two classes. Mutants A36P, L45PL54P, R140X, and G165fs display lowered solubility and structural stability, expose several buried residues to the surface, aggregate in vitro and in cellulo, and disturb/distort the Greek key motif. And they are associated with nuclear cataract. In contrast, mutants P24T and R77S, associated with peripheral cataract, behave quite similar to the wild type molecule, and do not affect the Greek key topology.

Conclusion

When a mutation distorts even one of the four Greek key motifs, the protein readily self-aggregates and precipitates, consistent with the phenotype of nuclear cataract, while mutations not affecting the motif display ‘native state aggregation’, leading to peripheral cataract, thus offering a protein structural rationale for the cataract phenotypic dichotomy “distort motif, lose central vision”.

Congenital cataract in a child with pyridoxine-dependent epilepsy

Pyridoxine-dependent epilepsy (PDE) is a cause of neonatal epileptic encephalopathy not previously known to cause ophthalmic disease. We describe the novel observation of a 5-year-old girl with pyridoxine-dependent epilepsy and bilateral cataracts. PDE is the result of mutations in the ALDH7A1 gene encoding antiquitin, an enzyme protective against cellular dehydration and osmotic stress. Accumulating metabolic precursors in PDE have been shown to be cataractogenic in vitro, and experimental pyridoxine deficiency has been associated with lenticular opacities in vivo. The association of ALDH7A1 haploinsufficiency in PDE and congenital cataract may offer insight into the relationship between osmotic stress and fetal cataract development. Bilateral progression of cataracts in this child suggests ongoing metabolic dysregulation within the crystalline lens despite pyridoxine supplementation at doses sufficient to control seizure activity.

Management and outcomes of cataract in children: the Toronto experience

PURPOSE

To review the management and outcomes of pediatric patients with cataract who were managed by one of two surgeons at a single institution.

METHODS

An observational series of consecutive cases identified from the hospital's outpatient billing records and surgical data program were used. Visual acuity was measured with the Snellen or Allen charts. Glaucoma was defined as IOP >20 mm Hg with clinical signs of glaucoma or visual field loss. Procedures for aphakic/pseudophakic glaucoma were excluded from analysis of additional surgeries performed subsequent to cataract extraction.

RESULTS

The search identified 778 patients (1,122 eyes) diagnosed with cataract over 10 years. Of these, 74% of eyes were treated surgically. Those patients with total, nuclear, and lamellar cataracts were significantly more likely than the overall population to undergo surgery. Additional surgeries were required in 12% of surgically treated eyes, with pseudophakic eyes representing more than one-half. Aphakic and pseudophakic glaucoma prevalence were 12% and 1%, respectively. Cataract morphology was not found to be a predisposing factor in the development of glaucoma. Visual outcomes were significantly better for posterior subcapsular (P = 0.0001), nuclear (P = 0.025), lamellar (P = 0.03), and traumatic cataracts (P = 0.005) than for other morphological types at all ages. Visual acuity was 20/30 or better in 63% of children with unilateral pseudophakia, 45% of children with unilateral aphakia, and approximately 75% of children with bilateral aphakia and pseudophakia.

CONCLUSIONS

Patients with total, nuclear, and lamellar cataracts were more likely to undergo surgery. Approximately 10% of patients required additional surgeries. No cataract morphology predisposed patients to developing glaucoma. Good visual outcomes were attained in bilaterally pseudophakic/aphakic and unilaterally pseudophakic children.