Primary congenital glaucoma

Secondary glaucoma after bevacizumab injection in Type-1 retinopathy of prematurity

Purpose

The authors report three separate cases of type 1 retinopathy of prematurity (ROP) treated with intravitreal bevacizumab before, or at 34 weeks postmenstrual age (PMA), with subsequent development of secondary glaucoma.

Observations

All three cases involve patients born ≤24 weeks and meeting the American Academy of Pediatrics criteria for ROP screening. Prior to treatment, each patient was noted to have normal anterior chamber structures with no signs of glaucoma. Each patient developed type 1 ROP and was treated with intravitreal bevacizumab, which was administered at or before 34 weeks PMA. Following the administration of intravitreal anti-vascular endothelial growth factor (VEGF), each patient developed a suspected open-angle glaucoma (OAG) within an approximate 4-week time frame. In these cases, the presentation of glaucoma differed from those that have been previously reported in the literature.

Conclusion and importance

Based on similar timing of glaucoma development following intravitreal bevacizumab injections, we hypothesize that the administration of anti-VEGF agents to very premature infants (≤24 weeks) at or before 34 weeks PMA, may predispose them to the development of secondary glaucoma through an unknown and possibly novel pathway.

Increasing the diagnostic yield of childhood glaucoma cases recruited into the 100,000 Genomes Project

Childhood glaucoma (CG) encompasses a heterogeneous group of genetic eye disorders that is responsible for approximately 5% of childhood blindness worldwide. Understanding the molecular aetiology is key to improving diagnosis, prognosis and unlocking the potential for optimising clinical management. In this study, we investigated 86 CG cases from 78 unrelated families of diverse ethnic backgrounds, recruited into the Genomics England 100,000 Genomes Project (GE100KGP) rare disease cohort, to improve the genetic diagnostic yield. Using the Genomics England/Genomic Medicine Centres (GE/GMC) diagnostic pipeline, 13 unrelated families were solved (13/78, 17%). Further interrogation using an expanded gene panel yielded a molecular diagnosis in 7 more unrelated families (7/78, 9%). This analysis effectively raises the total number of solved CG families in the GE100KGP to 26% (20/78 families). Twenty-five percent (5/20) of the solved families had primary congenital glaucoma (PCG), while 75% (15/20) had secondary CG; 53% of this group had non-acquired ocular anomalies (including iris hypoplasia, megalocornea, ectopia pupillae, retinal dystrophy, and refractive errors) and 47% had non-acquired systemic diseases such as cardiac abnormalities, hearing impairment, and developmental delay. CYP1B1 was the most frequently implicated gene, accounting for 55% (11/20) of the solved families. We identified two novel likely pathogenic variants in the TEK gene, in addition to one novel pathogenic copy number variant (CNV) in FOXC1. Variants that passed undetected in the GE100KGP diagnostic pipeline were likely due to limitations of the tiering process, the use of smaller gene panels during analysis, and the prioritisation of coding SNVs and indels over larger structural variants, CNVs, and non-coding variants.

Epidemiological analysis of congenital glaucoma: a national scenario

INTRODUCTION

Congenital glaucoma is a disease that involves increased intraocular pressure and can result in irreversible visual deterioration. The study of epidemiology allows the delineation of the characteristics associated with patients and specific risk factors.

OBJECTIVE

The objective of this study was to examine epidemiological trends, place of residence, duration of gestation, sex, and race of the newborn diagnosed with congenital glaucoma in Brazil.

METHODS

Data from SINASC (National Live Birth System) were used to analyze the period from 2017 to 2021 in Brazil. Linear regression and analysis of variance tests were employed to assess significance. The statistical significance was determined by p<0.05.

RESULTS

A total of 47 cases of congenital glaucoma were identified in Brazil during the study period, with the highest incidence between the years of 2018 and 2021. The analysis of the distribution indicated that the states with the highest incidence were São Paulo, followed by Rio Grande do Sul and Pernambuco. Approximately 60% of cases occurred in male individuals, compared with 19 female cases. The ethnic analysis showed the highest incidence among whites and mixed. Regarding the length of pregnancy, statistical differences were observed between newborns of different periods of gestation. Infants born from pregnancies lasting between 28 and 31 weeks and 32 and 36 weeks were significant when analyzed with the group between 37 and 41 weeks.

CONCLUSION

Studies on the mechanisms of congenital glaucoma seek to improve knowledge about the disease. Epidemiological evaluation is essential for identifying demographic and clinical patterns of the disease.

Factors and outcomes associated with corneal edema and Haabs striae in primary congenital glaucoma

PURPOSE

To identify specific factors and outcomes associated with corneal edema and Haabs striae in primary congenital glaucoma (PCG).

METHODS

The medical records of patients with PCG from 2011 to 2023 with >3 months' follow-up were reviewed retrospectively. Preoperative details and final outcomes were compared between eyes with and without corneal findings. The right eye of bilateral cases and the affected eye in unilateral cases were included.

RESULTS

A total of 58 patients (104 eyes, 69% male) underwent initial angle surgery at an average age of 297 ± 368 (median, 134) days. Corneal edema and Haabs striae were present preoperatively in 72 (69%) eyes of 41 patients and 68 (65%) eyes of 39 patients, respectively. Patients with corneal edema presented at a younger age (P < 0.0001) and with shorter axial length (P = 0.01) than those without edema. Univariate analysis showed that corneal edema was associated with worse visual acuity at final follow-up (OR = 4.4; 95% CI, 1.2-25.3). Patients with Haabs striae were older than those without striae (P = 0.04). After angle surgery, corneal edema was present at 1 month in 71% (95% CI, 52-84), at 2 months in 26% (95% CI, 12-42), at 3 months in 16% (95% CI, 6-30), and at 1 year in 3% (95% CI, 0-13). Corneal opacification did not resolve in 4 eyes of 3 patients after >4 years of follow-up.

CONCLUSIONS

In our study cohort, corneal edema resolved in the majority of PCG cases within 2-3 months of initial angle surgery but was associated with younger age at presentation and worse visual acuity at final follow-up.

Primary congenital glaucoma: We are always on the way

Primary congenital glaucoma (PCG), a developmental glaucoma occurring due to angle anomaly, earns growing concerns among ophthalmologists for its vision-damaging attribute. The incidence of PCG varies among races and geographic regions and is mostly genetically associated. Theories have been posed in attempt to address the etiology of this congenital maldevelopment and in the meanwhile providing evidence for feasibility of PCG surgeries. In regard to the clinical aspects of this entity, both the clinical characteristics and general principals of management are introduced, with angle surgeries highlighted for clarifying details including their success rates, key points for a successful surgical intervention, postoperative management, and follow-up strategies. Taking patients' vision-associated quality of life into consideration, we stressed that further perceptual learning and low vision rehabilitation are momentous. However, much has yet to be elucidated in respect of the truly comprehensive pathogenesis underneath as well as means by which clinical outcomes of PCG can be further improved. We are now looking forward to innovative therapeutic approaches like gene therapy in specific genes in the future, with the hope of improving their life-long visual quality in those young patients.

Primary congenital glaucoma: An iridotrabeculodysgenesis?

PURPOSE

To analyze primary congenital glaucoma (PCG) anterior chamber and angle anomalies over 360° as possible biomarkers of severity and prognosis.

METHODS

A cross-sectional observational study was conducted analyzing anterior segment anomalies of PCG patients over 4 years of age who underwent trabeculectomy combined with trabeculotomy and age-matched controls using anterior segment optical coherence tomography (ASOCT), CASIA-2. Anterior iridotrabecular adhesions or anterior iris insertion was identified and quantified from the scleral spur using the iridotrabecular contact (ITC) index parameter as a surrogate.

RESULTS

There was a variable but significantly increased anterior iridotrabecular adhesion on ITC index, ITC area, corneal volume, anterior chamber volume, iris volume, anterior chamber depth, and small/absent trabecular meshwork in PCG eyes compared to control eyes. In PCG eyes, anterior iridotrabecular adhesion had a positive correlation with pre-operative central corneal thickness (CCT) (r = 0.53, P = 0.02), review iris thickness (r = 0.4, P = 0.04), and ITC area (r = 0.85, P < 0.001). Review iris thickness had a negative correlation with pre-operative vertical cup-disc ratio (r = -0.51, P = 0.008). Iris hypoplasia with fewer or absent folds, collarette, pupillary ruff, and pupillary ruff to collarette distance was significantly different from controls.

CONCLUSION

ASOCT in PCG eyes has shown that they have variable anterior iridotrabecular tissue adhesions, anomalous tissue/membranes in the angle, and iris hypoplasia correlating with pre-operative cup-disc ratio. These features could be used as gonioscopic and clinical biomarkers to assess the severity and prognosis of the disease. The presence of abnormal iris morphology and iridotrabecular tissue anomalies in PCG suggests that it is more than just isolated trabeculodysgenesis and is probably best considered as part of the anterior segment dysgenesis spectrum.

Long-term functional and structural outcomes in patients with primary congenital glaucoma-A Danish nationwide study

PURPOSE

Evaluation of long-term functional and structural outcomes in patients with primary congenital glaucoma (PCG) based on visual acuity (VA), visual field (VF) using standard automated perimetry, and peripapillary retinal nerve fibre layer thickness (pRNFL).

METHODS

We retrospectively reviewed medical records of all patients diagnosed with PCG in Denmark from 1977 to 2016. Severe vision loss was defined as VA <6/60 and/or VF >20 decibels (dB). Prognostic factors were evaluated in a correlation matrix.

RESULTS

The median age of the 94 patients (153 PCG eyes) was 12 years (IQR 9-16). In PCG eyes 62% had VA ≥6/18 but 22% had <6/60. VA in the better seeing eye was ≥6/18 in 90% and <6/60 in 5%. VF was measured in 59 PCG eyes and the median mean defect was 5.1 dB (IQR 2.1-9.6) with 52% better than 6 dB and 9% worse than 20 dB. Generalized pRNFL was reduced below the age-expected 1st percentile in 29% of the 58 PCG eyes where pRNFL was measured. Poor VA, poor VF and reduced pRNFL were all correlated (p = 0.0001). More surgeries (p < 0.0001) and longer diagnostic delay (p = 0.004) were associated with poorer vision and to a lesser degree with poor VF pRNFL.

CONCLUSION

In Denmark, most patients with bilateral PCG retain VA ≥6/18 in the better seeing eye. Poor VA was associated with poor VF. Longer diagnostic delay and more surgeries were associated with a poorer prognosis.

Chemical Insights into Topical Agents in Intraocular Pressure Management: From Glaucoma Etiopathology to Therapeutic Approaches

Glaucoma encompasses a group of optic neuropathies characterized by complex and often elusive etiopathology, involvihttng neurodegeneration of the optic nerve in conjunction with abnormal intraocular pressure (IOP). Currently, there is no cure for glaucoma, and treatment strategies primarily aim to halt disease progression by managing IOP. This review delves into the etiopathology, diagnostic methods, and treatment approaches for glaucoma, with a special focus on IOP management. We discuss a range of active pharmaceutical ingredients used in glaucoma therapy, emphasizing their chemical structure, pharmacological action, therapeutic effectiveness, and safety/tolerability profiles. Notably, most of these therapeutic agents are administered as topical formulations, a critical aspect considering patient compliance and drug delivery efficiency. The classes of glaucoma therapeutics covered in this review include prostaglandin analogs, beta blockers, alpha agonists, carbonic anhydrase inhibitors, Rho kinase inhibitors, and miotic (cholinergic) agents. This comprehensive overview highlights the importance of topical administration in glaucoma treatment, offering insights into the current state and future directions of pharmacological management in glaucoma.

Ubiquitin proteasome system and glaucoma: A survey of genetics and molecular biology studies supporting a link with pathogenic and therapeutic relevance

Glaucoma represents a group of progressive neurodegenerative diseases characterized by the loss of retinal ganglion cells (RGCs) and their axons with subsequent visual field impairment. The disease develops through largely uncharacterized molecular mechanisms, that are likely to occur in different localized cell types, either in the anterior (e.g., trabecular meshwork cells) or posterior (e.g., Muller glia, retinal ganglion cells) segments of the eye. Genomic and preclinical studies suggest that glaucoma pathogenesis may develop through altered ubiquitin (Ub) signaling. Ubiquitin conjugation, referred to as ubiquitylation, is a major post-synthetic modification catalyzed by E1-E2-E3 enzymes, that profoundly regulates the turnover, trafficking and biological activity of the targeted protein. The development of new technologies, including proteomics workflows, allows the biology of ubiquitin signaling to be described in health and disease. This post-translational modification is emerging as a key role player in neurodegeneration, gaining relevance for novel therapeutic options, such as in the case of Proteolysis Targeting Chimeras technology. Although scientific evidence supports a link between Ub and glaucoma, their relationship is still not well-understood. Therefore, this review provides a detailed research-oriented discussion on current evidence of Ub signaling in glaucoma. A review of genomic and genetic data is provided followed by an in-depth discussion of experimental data on ASB10, parkin and optineurin, which are proteins that play a key role in Ub signaling and have been associated with glaucoma.

Glaucoma: now and beyond

The glaucomas are a group of conditions leading to irreversible sight loss and characterised by progressive loss of retinal ganglion cells. Although not always elevated, intraocular pressure is the only modifiable risk factor demonstrated by large clinical trials. It remains the leading cause of irreversible blindness, but timely treatment to lower intraocular pressure is effective at slowing the rate of vision loss from glaucoma. Methods for lowering intraocular pressure include laser treatments, topical medications, and surgery. Although modern surgical innovations aim to be less invasive, many have been introduced with little supporting evidence from randomised controlled trials. Many cases remain undiagnosed until the advanced stages of disease due to the limitations of screening and poor access to opportunistic case finding. Future research aims to generate evidence for intraocular pressure-independent neuroprotective treatments, personalised treatment through genetic risk profiling, and exploration of potential advanced cellular and gene therapies.

Long-Term Results of Combined Trabeculotomy Trabeculectomy in Primary Congenital Glaucoma

PRCIS

Primary congenital glaucoma (PCG) in Tunisian children seems to be characterized by a high prevalence of inherited and advanced forms of the disease. Primary combined trabeculotomy trabeculectomy (CTT) allowed satisfactory long-term intraocular pressure (IOP) control and reasonable visual outcome.

PURPOSE

To report the long-term outcome of CTT as the initial glaucoma surgery in children with PCG.

METHODS

Retrospective analysis of children who underwent primary CTT for PCG between January 2010 and December 2019. The main outcome measures were IOP reduction, corneal clarity, complications, refractive errors, and visual acuity (VA). Success was defined as IOP <16 mm Hg without (complete) or with (qualified) antiglaucoma medication. The WHO criteria of vision loss were used to categorize visual impairment (VI).

RESULTS

Of 62 patients, 98 eyes were enrolled. At the last follow-up, the mean IOP was reduced from 22.7 ± 4.0 mm Hg to 9.7 ± 3.9 mm Hg ( P < 0.0001). The complete success rate was 91.6%, 88.4%, 84.7%, 71.6%, 59.7%, and 54.3%, at the first, second, fourth, sixth, eighth, and tenth year, respectively. Follow-up averaged 42.1 ± 28.4 months. Preoperatively, 72 eyes (73.5%) had significant corneal edema versus 11 eyes (11.2%) at the end of the follow-up ( P < 0.0001). Endophthalmitis was encountered in one eye. Myopia was the most common refractive error (80.6%). Data on Snellen VA were available for 53.2% of the patients; 33.3% achieved a VA ≥6/12, 21.2% had mild VI, 9.1% had moderate VI, 21.2% had severe VI, and 15.2% were blind. The failure rate was statistically correlated to the early disease onset (<3 mo) and to preoperative corneal edema ( P = 0.022 and P = 0.037, respectively).

CONCLUSION

Primary CTT seems to be a good procedure in a population with advanced PCG at presentation, problematic follow-up visits, and limited resources.

Outcomes of Corneal Transplant in Childhood Glaucoma

PRCIS

Childhood glaucoma produces alterations in the postnatal development and function of various ocular structures, including the cornea. Childhood glaucoma patients present lower corneal transplant survival rates. Our series shows outcomes of corneal transplant in childhood glaucoma with survival rates of 29% at 2 years.

OBJECTIVE

To investigate the surgical outcome of different types of keratoplasty in eyes with childhood glaucoma.

PATIENTS AND METHODS

A retrospective review was made of the medical records from 17 eyes of 15 patients who were diagnosed with childhood glaucoma and received a corneal transplantation between January 2010 and July 2020. Patient demographics, intraocular pressure, previous ocular surgery, comorbidities, corneal transplant surgery, and follow-up outcome were collected. The primary efficacy endpoint was graft survival (in months) until failure, the latter being considered as irreversible loss of corneal transparency. Secondary efficacy points were the need for an increase in topical hypotensive therapy and the need for additional surgery.

RESULTS

Seventeen eyes of 15 patients were included, 11 eyes (10 patients) with primary congenital glaucoma and 6 with other types of childhood glaucoma. Corneal transplantation was performed at the mean age of 23.76 ± 14.86 years. At the time of the transplantation, the number of topical medications was 1.35 ± 1.27, intraocular pressure was 15.00 ± 8.34 mm Hg, and patients had received up to 7 glaucoma surgeries. Descemet stripping automated endothelial keratoplasty was performed in 13 eyes (76%) and penetrating keratoplasty in 4 (24%). After surgery, 7 (41%) eyes required increased topical treatment and 2 (12%) glaucoma surgery. Twelve eyes (71%) developed graft failure at 24 months, the mean time of survival being 13.88 ± 8.25 months.

CONCLUSIONS

Management of corneal decompensation in childhood glaucoma poses a challenge. In this series of childhood glaucoma with corneal transplantations, the survival rate was 29% at 24 months.

Aqueous Humor Cytokine Profile in Primary Congenital Glaucoma

BACKGROUND

Cytokine profile in patients with primary open-angle glaucoma (POAG) differs from that in healthy controls. Due to the different pathophysiological mechanisms involved in the genesis of primary congenital glaucoma (PCG) and POAG, it is possible that the cytokine profile could also differ. The main objective of this study was to compare the concentrations of cytokines in the aqueous humor of patients with PCG with those of POAG patients and a control group.

METHODS

A cross-sectional study was conducted. Aqueous humor samples were taken from PCG and POAG patients eligible for glaucoma or cataract surgery and from patients undergoing cataract surgery. Twenty-seven cytokines were analyzed using the Human Cytokine 27-Plex Immunoassay Kit (Bio-Rad Laboratories, Hercules, CA, USA).

RESULTS

A total of 107 subjects were included: patients with PCG (n = 19), patients with POAG (n = 54), and a control group (CG) of patients undergoing cataract surgery (n = 34). Most cytokines measured in aqueous humor in PCG presented decreased values compared with POAG and controls. A statistically significant difference was observed in IL-1ra, IL-2, IL-5, IL-7, IL-8, IL-10, IL-12, IL-15, IL-17A, Eotaxin, FGF basic, G-CSF, GM-CSF, IFN-γ, MIP-1α, PDGF-bb, MIP-1β, RANTES, TNF-α, and VEGF.

CONCLUSION

PCG patients have a cytokine profile in aqueous humor different from POAG patients and patients without glaucoma, characterized by lower concentrations of multiple cytokines.

Screening of candidate genes at GLC3B and GLC3C loci in Chinese primary congenital glaucoma patients with targeted next generation sequencing

BACKGROUND

Primary congenital glaucoma (PCG) is characterized by developmental abnormalities of the anterior chamber angle. Although several genes have been associated with PCG, pathogenic mutations could only be detected in about 20% of Chinese patients. GLC3B (1p36.2-36.1) and GLC3C (14q24.3) loci were previously identified in PCG pedigrees via linkage analysis. However, no causative genes were reported in these loci. This study was designed to search for novel PCG-related genes in these genetic regions.

MATERIALS AND METHODS

DNA samples from 100 PCG patients and 200 normal controls were pooled and sequenced using a customized panel of 133 positional candidate genes located around GLC3B and GLC3C loci (±1Mb). PCG-related genes were prioritized by the distribution of variants between patients and controls. Confirmation of selected variants and co-segregation analysis were performed using Sanger sequencing.

RESULTS

Patient and control group contained 116 and 147 rare variants respectively after screening. Three genes (ZC2HC1C, VPS13D, and PGF) were prioritized according to the distribution of variants between the two groups. Rare variants of PGF were only identified in PCG patients.

CONCLUSIONS

To the best of our knowledge, this is the first study aiming at exploring novel PCG-related genes at GLC3B and GLC3C loci. Our preliminary results suggest that there are potential associations between ZC2HC1C, VPS13D, PGF, and PCG. However, larger cohort studies and functional assays are required to provide further evidence for the proposed genotype-phenotype association.

Outcomes of Penetrating Canaloplasty in Childhood Glaucoma

PRCIS

Penetrating canaloplasty was safe and effective for the management of refractory childhood glaucoma.

PURPOSE

The purpose of this paper is to report the safety and efficacy of penetrating canaloplasty for the management of childhood glaucoma.

MATERIALS AND METHODS

This single-center prospective interventional case series enrolled 50 eyes of 32 patients with childhood glaucoma between July 2017 and July 2020. Penetrating canaloplasty to create direct communication between the anterior chamber and tensioning suture-dilated the Schlemm canal was performed through a trabecular meshwork ostium in the affected eyes. Preoperative and postoperative intraocular pressure (IOP), number of glaucoma medications, and procedure-related complications were recorded. Qualified and complete success was defined as IOP≥5 and ≤21 mm Hg with or without glaucoma medications, respectively.

RESULTS

A total of 43 eyes (86.0%) achieved 360 degrees catheterization of Schlemm canal and completed penetrating canaloplasty. The median age at surgery was 5 years (range, 10 d-17 y, mean 6.20±5.46 y). The mean IOP decreased from 33.11±10.89 mm Hg on 2 medications (median, range: 0-5) before surgery to 13.46±4.71 mm Hg on 0 medications (median, range:0-2) postoperatively at 12 months ( P <0.001). Complete and qualified success rates were 81.08% and 89.19%, respectively, at the 12-month follow-up. Hyphema (6/43, 13.95%) and a transient shallow anterior chamber with hypotony (5/43, 11.63%) were the most commonly observed early complications.

CONCLUSION

Penetrating canaloplasty demonstrated good safety and efficacy in eyes with childhood glaucoma, and may be considered an option for managing refractory childhood glaucoma.

An Efficient Approach to Predict Eye Diseases from Symptoms Using Machine Learning and Ranker-Based Feature Selection Methods

The eye is generally considered to be the most important sensory organ of humans. Diseases and other degenerative conditions of the eye are therefore of great concern as they affect the function of this vital organ. With proper early diagnosis by experts and with optimal use of medicines and surgical techniques, these diseases or conditions can in many cases be either cured or greatly mitigated. Experts that perform the diagnosis are in high demand and their services are expensive, hence the appropriate identification of the cause of vision problems is either postponed or not done at all such that corrective measures are either not done or done too late. An efficient model to predict eye diseases using machine learning (ML) and ranker-based feature selection (r-FS) methods is therefore proposed which will aid in obtaining a correct diagnosis. The aim of this model is to automatically predict one or more of five common eye diseases namely, Cataracts (CT), Acute Angle-Closure Glaucoma (AACG), Primary Congenital Glaucoma (PCG), Exophthalmos or Bulging Eyes (BE) and Ocular Hypertension (OH). We have used efficient data collection methods, data annotations by professional ophthalmologists, applied five different feature selection methods, two types of data splitting techniques (train-test and stratified k-fold cross validation), and applied nine ML methods for the overall prediction approach. While applying ML methods, we have chosen suitable classic ML methods, such as Decision Tree (DT), Random Forest (RF), Naive Bayes (NB), AdaBoost (AB), Logistic Regression (LR), k-Nearest Neighbour (k-NN), Bagging (Bg), Boosting (BS) and Support Vector Machine (SVM). We have performed a symptomatic analysis of the prominent symptoms of each of the five eye diseases. The results of the analysis and comparison between methods are shown separately. While comparing the methods, we have adopted traditional performance indices, such as accuracy, precision, sensitivity, F1-Score, etc. Finally, SVM outperformed other models obtaining the highest accuracy of 99.11% for 10-fold cross-validation and LR obtained 98.58% for the split ratio of 80:20.

Mutation screening of the CYP1B1 gene reveals thirteen novel disease-causing variants in consanguineous Pakistani families causing primary congenital glaucoma

Background

Primary congenital glaucoma (PCG) is a heterogeneous rare recessively inherited disorder prevalent in regions with high consanguinity. Disease phenotype is associated with increased intra ocular pressure and is a major cause of childhood blindness. Sequence variations in Cytochrome P450 1B1 (CYP1B1) gene are a major cause of PCG. Current study was conducted to screen CYP1B1 gene in highly consanguineous PCG affected families from Pakistani population consistent with the autosomal recessive pattern of PCG inheritance.

Methods

For this study, patients and controls (clinically unaffected individuals of each family) from 25 consanguineous families belonging to Punjab, Baluchistan and Khyber Pakhtunkhwa, Pakistan were recruited through ophthalmologists. DNA was isolated from collected blood samples. Genetic screening of CYP1B1 gene was done for all enrolled families. In-silico analysis was performed to identify and predict the potential disease-causing variations.

Results

Pathogenicity screening revealed sequence variants segregating with disease phenotype in homozygous or compound heterozygous form in eleven out of 25 analyzed families. We identified a total of sixteen disease causing variants among which five frameshift i.e., c.629dup (p.Gly211Argfs*13), c.287dup (p.Leu97Alafs*127), c.662dup (p.Arg222Profs*2), c.758_759insA (p.Val254Glyfs*73) and c.789dup (p.Leu264Alafs*63), two silent c.1314G>A, c.771T>G and six missense variations c.457C>G (p.Arg153Gly), c.516C>A (p.Ser172Arg), c.722T>A (p.Val241Glu), c.740T>A (p.Leu247Gln), c.1263T>A (p.Phe421Leu), and c.724G>C (p.Asp242His) are previously un reported. However two frameshift c.868dup (p.Arg290Profs*37), c.247del (p.Asp83Thrfs*12) and one missense variant c.732G>A (p.Met244Ile), is previously reported. Furthermore, six polymorphisms c.1347T>C, c.2244_2245insT, c.355G>T, c.1294G>C, c.1358A>G and c.142C>G were also identified. In the intronic region, a novel silent polymorphism i.e., g.35710_35711insT was found in homozygous state. All the newly detected disease-causing variants were negative in 96 ethnically matched controls.

Conclusion

Among twenty-five screened families, eight families (PCG50, 52–54, 58, 59, 63 and 67) were segregating disease causing variants in recessive manner. Two families (PCG049 and PCG062) had compound heterozygosity. Our data confirms genetic heterogeneity of PCG in Pakistani population however we did not find molecular variants segregating with PCG in fifteen families in coding exons and intron-exon boundaries of CYP1B1 gene. Genetic counseling was provided to families to refrain from practicing consanguinity and perform premarital screening as a PCG control measure in upcoming generations.

Animal Model Contributions to Primary Congenital Glaucoma

Primary congenital glaucoma (PCG) is an ocular disease characterized by congenital anterior segmental maldevelopment with progressive optic nerve degeneration. Certain genes, such as cytochrome P450 family 1 subfamily B member 1 and latent TGF-β-binding protein 2, are involved in the pathogenesis of PCG, but the exact pathogenic mechanism has not yet been fully elucidated. There is an urgent need to determine the etiology and pathophysiology of PCG and develop new therapeutic methods to stop disease progression. Animal models can simulate PCG and are essential to study the pathogenesis and treatment of PCG. Various animal species have been used in the study of PCG, including rabbits, rats, mice, cats, zebrafish, and quails. These models are formed spontaneously or by combining with genetic engineering technology. The focus of the present study is to review the characteristics and potential applications of animal models in PCG and provide new approaches to understand the mechanism and develop new treatment strategies for patients with PCG.

The genetics of glaucoma: Disease associations, personalised risk assessment and therapeutic opportunities-A review

Glaucoma refers to a heterogenous group of disorders characterised by progressive loss of retinal ganglion cells and associated visual field loss. Both early-onset and adult-onset forms of the disease have a strong genetic component. Here, we summarise the known genetic associations for various forms of glaucoma and the possible functional roles for these genes in disease pathogenesis. We also discuss efforts to translate genetic knowledge into clinical practice, including gene-based tests for disease diagnosis and risk-stratification as well as gene-based therapies.

Prematurity-Risk Factor or Coincidence in Congenital Glaucoma?

Background and Objective: To correlate the intraocular pressure with the postconceptional age and identify a statistically significant connection between congenital glaucoma and prematurity. Materials and Methods: The current paper is a retrospective, comparative, case-control study. Data collection featured maternal age, gestational age at birth, birth weight, and intraocular ocular pressure (IOP) measurements. Results: Forty-two eyes of 21 children underwent examination. The participants were assigned into two groups. The Preterm-Glaucoma (PG) group included eight preterm-born children diagnosed with glaucoma, whereas the Preterm (P) group was comprised of premature newborns without the aforementioned condition. There was no statistically relevant difference in birth weight (p = 0.691078) nor in mean gestational age (p = 0.752623) between the two groups. The mean IOP in the PG group was 23.813 ± 4.5493, whereas in the P group, it ranged around 13.231 ± 1.0699, p < 0.0001. Using mixed-effects models, we obtained a reduction in IOP of 0.45 mmHg per week in the first month of life. A further weekly reduction of 0.36 mmHg was achieved in the next two months. Conclusions: The mean IOP of prematurely born children decreased with age. Our findings correlate with previously conducted studies, however, the drop in IOP values exceeded any data published so far. We found no correlation between prematurity and the incidence of congenital glaucoma.

Psychosocial indicators of primary congenital glaucoma and filtering surgeries impacts on children and family's quality of life

PURPOSE

To identify psychosocial indicators and evaluate the filtering surgeries impacts on quality of life (QOL) of children with primary congenital glaucoma (PCG) and their family.

METHODS

Parents of children with bilateral PCG who underwent filtering surgery were included. Data were collected through: (a) psychological inquiry to determine psychosocial indicators; (b) Children's Visual Function Questionnaire (CVFQ). The associations between the CVFQ scores and visual acuity, intraocular pressure, optic disk cupping, horizontal corneal diameter, axial length, number of surgeries, and hypotensive eye drops were investigated. The statistical significance level was considered as p ⩽ 0.05.

RESULTS

The mean age of the nine mothers interviewed and their children (six boys and three girls) was 29 ± 5 years and 35 ± 18 months, respectively. The psychosocial indicators determined were: emotional impact of the diagnosis, disease knowledge, mother and family's feelings on facing the surgical treatment, surgical result comprehension, treatment adherence, child's emotional and behavioral reactions, social support, and future expectations. In CVFQ analysis, QOL score was strongly associated with visual acuity (r = -0.79; p = 0.01). Besides the treatment score was correlated to intraocular pressure (r = -0.68; p < 0.05), optic disk cupping (r = -0.85; p = 0.03), and corneal diameter (r = -0.69; p = 0.02). Correlations were not found for number of surgeries and eye drops.

CONCLUSIONS

This study confirmed the PCG surgical treatment impact on QOL and determined psychosocial indicators which may favor the suitable actions in psychological treatment and follow-up of the children and families.

Long-term success after trabeculotomy in primary congenital glaucoma - a study with up to 35 years follow-up

PURPOSE

To evaluate the surgical success after trabeculotomy for primary congenital glaucoma (PCG) in Denmark in the last 40 years.

METHODS

Retrospective review of medical files on children who all underwent trabeculotomy as the first surgical intervention between January 1rst, 1977 and December 31, 2016. Information on diagnosis and surgical procedures were extracted. Primary outcome was surgical success was defined as intraocular pressure (IOP) < 21 mmHg without medications one year after surgery. Secondary outcome was the number of reoperations needed.

RESULTS

Out of 118 children with PCG, 96 children (144 eyes) had an ab externo trabeculotomy as primary IOP lowering procedure opening Schlemm's channel 4 clock hours into the anterior chamber. Complete surgical success at one year was achieved in 73% (106 of 144 eyes). On the long term, IOP could be controlled by one surgical procedure in 2/3 of children, eight eyes required >5 surgical procedures to control IOP. In 12.1% of children the second glaucoma procedure was performed >5 years after the initial trabeculotomy. There was a tendency towards greater risk of needing a second procedure in patients < 3 months of age at primary trabeculotomy (hazard ratio, HR, 2.01, 95% CI 0.96-4.22) and in boys (HR 2.02, 95% CI 0.97-4.18) and a lower risk of requiring a third surgery if the second surgery was trabeculectomy with MMC.

CONCLUSION

Dedicated follow-up of patients with PCG is essential as the disease may continue to progress even after years of quiescence and some children need multiple surgeries to control IOP. Additional glaucoma procedures are required in 1/3 of children and boys and younger patients seem to be at greater risk.

Genetics and therapy for pediatric eye diseases

Ocular morphogenesis in vertebrates is a highly organized process, orchestrated largely by intrinsic genetic programs that exhibit stringent spatiotemporal control. Alternations in these genetic instructions can lead to hereditary or nonhereditary congenital disorders, a major cause of childhood visual impairment, and contribute to common late-onset blinding diseases. Currently, limited treatment options exist for clinical phenotypes involving eye development. This review summarizes recent advances in our understanding of early-onset ocular disorders and highlights genetic complexities in development and diseases, specifically focusing on coloboma, congenital glaucoma and Leber congenital amaurosis. We also discuss innovative paradigms for potential therapeutic modalities.

SVEP1 as a Genetic Modifier of TEK-Related Primary Congenital Glaucoma

Purpose

Affecting children by age 3, primary congenital glaucoma (PCG) can cause debilitating vision loss by the developmental impairment of aqueous drainage resulting in high intraocular pressure (IOP), globe enlargement, and optic neuropathy. TEK haploinsufficiency accounts for 5% of PCG in diverse populations, with low penetrance explained by variable dysgenesis of Schlemm's canal (SC) in mice. We report eight families with TEK-related PCG, and provide evidence for SVEP1 as a disease modifier in family 8 with a higher penetrance and severity.

Methods

Exome sequencing identified coding/splice site variants with an allele frequency less than 0.0001 (gnomAD). TEK variant effects were assayed in construct-transfected HEK293 cells via detection of autophosphorylated (active) TEK protein. An enucleated eye from an affected member of family 8 was examined via histology. SVEP1 expression in developing outflow tissues was detected by immunofluorescent staining of 7-day mouse anterior segments. SVEP1 stimulation of TEK expression in human umbilical vascular endothelial cells (HUVECs) was measured by TaqMan quantitative PCR.

Results

Heterozygous TEK loss-of-function alleles were identified in eight PCG families, with parent–child disease transmission observed in two pedigrees. Family 8 exhibited greater disease penetrance and severity, histology revealed absence of SC in one eye, and SVEP1:p.R997C was identified in four of the five affected individuals. During SC development, SVEP1 is secreted by surrounding tissues. SVEP1:p.R997C abrogates stimulation of TEK expression by HUVECs.

Conclusions

We provide further evidence for PCG caused by TEK haploinsufficiency, affirm autosomal dominant inheritance in two pedigrees, and propose SVEP1 as a modifier of TEK expression during SC development, affecting disease penetrance and severity.

Lens in Primary Congenital Glaucoma Eyes Treated by Combined Angle and Filtering Surgery

PURPOSE

To report on the changes in the natural crystalline lens in primary congenital glaucoma (PCG) eyes that had undergone previous combined angle-filtering surgery with antimetabolites.

SETTINGS

The pediatric ophthalmology unit of the ophthalmology department of Alexandria Main University Hospital.

DESIGN

A retrospective chart review.

METHODS

A retrospective chart review of patients presenting with and operated (by combined angle-filtering surgery with antimetabolites) for PCG in the period from 2005 to 2018. Any lens pathology was noted as well as the management and the outcome.

RESULTS

The records of 422 children (613 eyes) were reviewed. Lens pathology was noted in 54 (8.8%) eyes. Abnormalities in lens clarity (cataract) were detected in 31 (56%) eyes, and abnormalities in lens position (subluxation) were detected in 24 (44%) eyes. Management options included observation (in 28 eyes), lensectomy for aphakia (in 14 eyes), lensectomy with in the bag intraocular lens (IOL) implantation (in 11 eyes), and lensectomy with iris-fixated IOL (in 1 eye). Elevation of intraocular pressure (IOP) occurred in only 4 eyes (of 26 operated eyes, 15.3%) after lens extraction.

CONCLUSIONS

Changes in the natural crystalline lens clarity and/or position occurred in 8.8% (54 of 613) of PCG eyes operated by combined angle-filtering surgery with antimetabolites. Lens extraction was a relatively safe procedure with only 15% (4 of 26) of eyes suffering an elevation of IOP after lens extraction.

Genetic Epidemiology of Primary Congenital Glaucoma in the 22 Arab Countries: A Systematic Review

PURPOSE

Primary congenital glaucoma (PCG) is a rare glaucoma type that develops in early infantile period and contributes to an elevated pressure on ocular cavity. Variants in CYP1B1 gene are the most encountered in PCG cases. The prevalence of PCG is relatively high among Arabs, however its genetic epidemiology remains understudied. This study aims to systematically identify all reported PCG disease-causing variants in the Arab population and investigate their potential genotype-phenotype correlations.

METHODS

We searched four different databases (PubMed, ScienceDirect, Google Scholar, and Scopus) from the time of inception until July 2020. Broad search terms were used to capture all possible information about the genetic epidemiology of PCG among Arabs.

RESULTS

We identified a total of 77 disease-causing variants in 361 patients and 88 families; of these, 33 were unique to Arabs. Sixty-nine variants were identified in the CYP1B1 gene, five variants were in the MYOC gene and single variants were reported in NTF4, FOXC1, and WDR36 genes. The most common reported variant was the c.182 G > A in the CYP1B1 gene. All identified variants were from ten Arab Countries (Saudi Arabia, Kuwait, Oman, Egypt, Morocco, Lebanon, Tunisia, Iraq, Algeria, and Mauritania). We identified 44 shared variants with other ethnicities demonstrated a distinctive genotype-phenotype correlation. Consanguinity was observed in the majority of Arab PCG patients, ranging from 45% to 100%.

CONCLUSION

PCG causing variants were identified in 10 Arab countries, which were mostly detected in the CYB1P1 gene. Arab patients with PCG seem to have distinctive genotype-phenotype correlations.

Fouling in ocular devices: implications for drug delivery, bioactive surface immobilization, and biomaterial design

The last 30 years has seen a proliferation of research on protein-resistant biomaterials targeted at designing bio-inert surfaces, which are prerequisite for optimal performance of implantable devices that contact biological fluids and tissues. These efforts have only been able to yield minimal results, and hence, the ideal anti-fouling biomaterial has remained elusive. Some studies have yielded biomaterials with a reduced fouling index among which high molecular weight polyethylene glycols have remained dominant. Interestingly, the field of implantable ocular devices has not experienced an outflow of research in this area, possibly due to the assumption that biomaterials tested in other body fluids can be translated for application in the ocular space. Unfortunately, progression in the molecular understanding of many ocular conditions has brought to the fore the need for treatment options that necessitates the use of anti-fouling biomaterials. From the earliest implanted horsehair and silk seton for glaucoma drainage to the recent mini telescopes for sight recovery, this review provides a concise incursion into the gradual evolution of biomaterials for the design of implantable ocular devices as well as approaches used to overcome the challenges with fouling. The implication of fouling for drug delivery, the design of immune-responsive biomaterials, as well as advanced surface immobilization approaches to support the overall performance of implantable ocular devices are also reviewed.

Ab interno vs ab externo microcatheter-assisted trabeculotomy for primary congenital glaucoma with clear cornea

Importance

This is the first comprehensive comparison between ab interno approach and ab externo approach for microcatheter‐assisted trabeculotomy in primary congenital glaucoma with clear cornea.

Background

Ab externo microcatheter‐assisted trabeculotomy is considered to be the gold standard for primary congenital glaucoma. The novel ab interno approach would intuitively be similar to ab externo approach for microcatheter‐assisted trabeculotomy in eyes with clear cornea; however, there is no evidence yet.

Design

Non‐contemporary comparison of retrospective case series.

Participants

Fifty‐eight and fifty‐seven consecutive primary congenital glaucoma eyes with clear corneas underwent ab interno and ab externo microcatheter‐assisted trabeculotomy, respectively.

Methods

Retrospective comparison of clinical outcomes.

Main Outcome Measures

Surgical success was defined as a postoperative intraocular pressure of ≤21 mmHg with at least a 30% reduction from preoperative IOP with or without the use of anti‐glaucoma medication (qualified and complete success, respectively).

Results

The qualified success rate (87.9% vs 82.2%, P = .40) and complete success rates (81.0% vs 73.3%, P = .32) were comparable between groups. Complications were minimal and comparable. Less than 360° trabeculotomy (P = .009) and a higher number of previous surgeries (P = .03) were both associated with worse surgical outcomes.

Conclusions and Relevance

Ab interno approach provide good and comparable outcomes as ab externo approach for microcatheter‐assisted trabeculotomy in primary congenital glaucoma eyes with clear cornea. It should be considered as the initial choice in these patients with the benefit of sparing conjunctiva. Successful trabeculotomy with either technique during the first attempt is critical to overall success and underscores the need for proficiency before independent practice.

Intraocular Pressure Changes after Water Drinking Test in Surgically Treated Primary Congenital Glaucoma

Purpose

To assess intraocular pressure (IOP) changes after the water drinking test (WDT) in patients with primary congenital glaucoma (PCG).

Methods

In this prospective interventional study, 20 eyes of 20 patients with PCG were included. All patients had undergone trabeculotomy. Six out of twenty eyes had received a glaucoma drainage device (GDD) implantation. IOP was measured using an air-puff tonometer at baseline, and 15, 30, 45, and 60 min after WDT. The repeated-measures analysis of variance test was used to compare the mean IOPs at different time points.

Results

The mean ( ± standard deviation) of participants' age was 9.9 ± 2.7 years (range, 6 to 16 years), and 8 (40%) participants were male. The mean IOPs at baseline and 15, 30, 45, and 60 minutes after the WDT were 15.8 ± 3.7, 18.6 ± 3.4, 19.0 ± 3.8, 17.9 ± 3.8, and 16.9 ± 3.5 mmHg, respectively (P < 0.001). Pairwise comparisons revealed that the mean IOPs after 15 and 30 min were significantly greater than the baseline IOP (P < 0.001 and P = 0.002, respectively); however, the difference in mean IOPs after 45 and 60 min were not statistically significant from the baseline IOP. The averages of IOP peak and IOP fluctuation after the WDT were 20.0 ± 3.5 and 4.2 ± 2.9 mmHg, respectively. IOP fluctuation in those who underwent trabeculotomy alone was twice that of those with GDDs, but the difference was not statistically significant (5.0 vs 2.5 mmHg; P = 0.08).

Conclusion

In patients with PCG, WDT induced significant IOP elevation 15 and 30 min after the test, which returned to pre-test values after 45 min.

Retinal Pigment Epithelium Cell Density and Bruch's Membrane Thickness in Secondary versus Primary High Myopia and Emmetropia

To assess differences between secondary high myopia (SHM) due to congenital glaucoma and primary high myopia (PHM) and non-highly myopic eyes (NHM) in the relationships between axial length and Bruch's membrane (BM) thickness and retinal pigment epithelium (RPE) density. The histomorphometric study included human globes enucleated for reasons such as malignant uveal melanoma, end-stage painful secondary angle-closure glaucoma and congenital glaucoma. BM thickness and RPE cell density were measured upon light microscopy. The investigation included 122 eyes (mean axial length: 26.7 ± 3.7 mm; range: 20.0-37.0 mm): 7 eyes with SHM (axial length: 33.7 ± 2.1 mm; range: 31.0-37.0 mm), 56 eyes with PHM (mean axial length: 29.1 ± 2.4 mm; range: 26.0-36.0 mm) and 59 eyes in the NHM-group (axial length: 23.5 ± 1.3 mm; range: 20.0-25.5 mm). In the SHM group, longer axial length was associated with lower RPE cell density at the posterior pole (standardized regression coefficient beta: 0.92; non- standardized regression coefficient B: -2.76; 95% confidence interval (CI): -4.41, -1.10;P = 0.01), at the midpoint posterior pole/equator (beta: -0.87; B: -3.60; 95% CI: -6.48, -0.73;P = 0.03), and at the equator (beta: -0.88; B: -0.95; 95% CI: -1.68, -0.23; P = 0.02), but not at the ora serrata (P = 0.88). In the PHM-group and NHM group, RPE cell density at the posterior pole (P = 0.08) and ora serrata (P = 0.88) was statistically independent of axial length, while at the midpoint posterior pole/equator (P = 0.01) and equator (P < 0.001), RPE cell density decreased with longer axis. BM thickness in the SHM group decreased with longer axial length at the posterior pole (beta: -0.93;B: -0.29; 95% CI: -0.39, -0.14; P = 0.003), midpoint posterior pole/equator (beta: -0.79; B: -0.22; 95% CI: -0.42, -0.02; P = 0.035) and equator (beta: -0.84; B: -0.21; 95% CI: -0.37, -0.06; P = 0.017), while in the PHM-group and NHM-group, BM thickness at any ocular region was not statistically significantly correlated with axial length (all P > 0.05). In the SHM-group, but not in the PHM-group or NHM-group (P = 0.98), lower BM thickness was associated with lower RPE cell density (beta: 0.93; B: 0.09; 95% CI: 0.04, 0.14; P = 0.007), while in the eyes without congenital glaucoma the relationship was not statistically significant. In SHM in contrast to PHM, BM thickness and RPE cell density decrease in a parallel manner with longer axial length. The findings fit with the notion of BM being a primary driver in the process of axial elongation in PHM as compared to SHM.

Contemporary management of refractory pediatric glaucoma

PURPOSE OF REVIEW

The management of pediatric glaucoma poses a unique challenge in terms of maintaining lifelong vision and combating an aggressive scarring response from surgery. Contemporary literature regarding the surgical management of children with pediatric glaucoma who fail, or are at a high risk of failure, from conventional surgery is limited. The aim of this review is to highlight recent developments in relation to the current opinion regarding the management of children with refractory pediatric glaucoma.

RECENT FINDINGS

Some studies have reported impressive success rates with circumferential trabeculotomy, even in eyes with previous failed surgery. Early results of deep sclerectomy in populations which may not respond well to conventional angle surgery are encouraging but data is limited for the pediatric age group. In compliant patients in whom multiple postoperative examinations under anesthesia are possible, trabeculectomy remains an effective procedure. Multiple recent studies have demonstrated that glaucoma drainage device (GDD) surgery is associated with 5-year success rates of over 70% in primary childhood glaucomas.

SUMMARY

Glaucoma drainage device surgery is likely to remain a mainstay of surgical management for refractory glaucoma in older children. More prospective data are needed on the success of circumferential trabeculotomy, deep sclerectomy and micropulse laser in pediatric eyes with previous failed surgery. VIDEO ABSTRACT: http://links.lww.com/COOP/A34.

The identification and stereochemistry analysis of a novel mutation p.(D367Tfs*61) in the CYP1B1 gene: A case report

Purpose:

To investigate the presence of a probable genetic defect(s) that may cause primary congenital glaucoma (PCG) in a seven-year-old female patient.

Methods:

A seven-year-old female patient and her family received genetic counseling and underwent full clinical examinations by an expert ophthalmologist. The patient's genomic DNA was subjected to the targeted gene capture and next-generation sequencing (NGS) along with Sanger sequencing method. The 3D structure prediction and stereochemistry analysis were performed for both mutant and wild-type forms of the CYP1B1 protein.

Results:

The clinical examinations indicated that the diagnosis of PCG was correctly made. We identified a novel homozygous deletion in which a “C” nucleotide was deleted from the final exon of the Cytochrome P450 Family 1 Subfamily B Member 1 (CYP1B1) gene. The 3D molecular modeling of the CYP1B1 protein predicted significant structural changes could occur in this protein as a result of the mutation mentioned earlier. The stereochemistry analysis revealed mutant features of the protein, as well as significant misfolding and possible malfunctions in the mutant form of the CYP1B1 protein.

Conclusions:

This mutation might cause a frameshift in the translation process, leading to the malfunction of the CYP1B1 protein and development of glaucoma. This newly-identified mutation could be regarded as potential deletion mutation in genetic counseling and molecular examination for the detection of PCG disease in Iran.

Assessment of the anterior segment of patients with primary congenital glaucoma using handheld optical coherence tomography

PURPOSE

To investigate the potential of handheld optical coherence tomography (HH-OCT) in assessing the anterior segment of the eye in patients with primary congenital glaucoma.

DESIGN

A prospective, case-controlled observational study.

PARTICIPANTS

Twenty-two patients with primary congenital glaucoma (PCG, 9 females and 13 males; mean age 4.36 ± 3.4 years) and age-, gender- and ethnicity-matched healthy participants.

METHODS

Anterior OCT was performed in all participants using a high-resolution HH SD-OCT device (Envisu 2300, Leica Microsystems, Germany) without anaesthesia or sedation.

RESULTS

Anterior HH-OCT in PCG visualised Haab's striae in 14.3%, uneven internal cornea in 9.5% and epithelial thickening in 11.9% of patients with central corneal thickening (CCT, p < 0.001). CCT was significantly correlated with the intraocular pressure (IOP, p < 0.001). The flat iris with a thin collarette zone was found in 59.5%, anterior iris insertion in 11.90% of eyes affected by PCG. Two independent examiners showed sensitivity and specificity of 87% and 77%, respectively, by instating iris thinning and flattening of the anterior profile.

CONCLUSIONS

Anterior HH-OCT has significant potential to improve diagnosis and management of PCG. Clinically relevant information can be obtained non-invasively and without sedation. High specificity makes anterior HH-OCT an important adjunct for management of PCG. Excellent visualisation of the iris insertion on OCT indicates potential for AS OCT to assist with surgical planning, including decision on the type of surgery and location of the incision.

Ciliary margin-derived BMP4 does not have a major role in ocular development

Heterozygous Bmp4 mutations in humans and mice cause severe ocular anterior segment dysgenesis (ASD). Abnormalities include pupil displacement, corneal opacity, iridocorneal adhesions, and variable intraocular pressure, as well as some retinal and vascular defects. It is presently not known what source of BMP4 is responsible for these defects, as BMP4 is expressed in several developing ocular and surrounding tissues. In particular, BMP4 is expressed in the ciliary margins of the optic cup which give rise to anterior segment structures such as the ciliary body and iris, making it a good candidate for the required source of BMP4 for anterior segment development. Here, we test whether ciliary margin-derived BMP4 is required for ocular development using two different conditional knockout approaches. In addition, we compared the conditional deletion phenotypes with Bmp4 heterozygous null mice. Morphological, molecular, and functional assays were performed on adult mutant mice, including histology, immunohistochemistry, in vivo imaging, and intraocular pressure measurements. Surprisingly, in contrast to Bmp4 heterozygous mutants, our analyses revealed that the anterior and posterior segments of Bmp4 conditional knockouts developed normally. These results indicate that ciliary margin-derived BMP4 does not have a major role in ocular development, although subtle alterations could not be ruled out. Furthermore, we demonstrated that the anterior and posterior phenotypes observed in Bmp4 heterozygous animals showed a strong propensity to co-occur, suggesting a common, non-cell autonomous source for these defects.

Congenital glaucoma and CYP1B1: an old story revisited

Primary congenital glaucoma is a trabecular meshwork dysgenesis with resultant increased intraocular pressure and ocular damage. CYP1B1 mutations remain the most common identifiable genetic cause. However, important questions about the penetrance of CYP1B1-related congenital glaucoma remain unanswered. Furthermore, mutations in other genes have been described although their exact contribution and potential genetic interaction, if any, with CYP1B1 mutations are not fully explored. In this study, we employed modern genomic approaches to re-examine CYP1B1-related congenital glaucoma. A cohort of 193 patients (136 families) diagnosed with congenital glaucoma. We identified biallelic CYP1B1 mutations in 80.8% (87.5 and 66.1% in familial and sporadic cases, respectively, p < 0.0086). The large family size of the study population allowed us to systematically examine penetrance of all identified alleles. With the exception of c.1103G>A (p.R368H), previously reported pathogenic mutations were highly penetrant (91.2%). We conclude from the very low penetrance and genetic epidemiological analyses that c.1103G>A (p.R368H) is unlikely to be a disease-causing recessive mutation in congenital glaucoma as previously reported. All cases that lacked biallelic CYP1B1 mutations underwent whole exome sequencing. No mutations in LTBP2, MYOC or TEK were encountered. On the other hand, mutations were identified in genes linked to other ophthalmic phenotypes, some inclusive of glaucoma, highlighting conditions that might phenotypically overlap with primary congenital glaucoma (SLC4A4, SLC4A11, CPAMD8, and KERA). We also encountered candidate causal variants in genes not previously linked to human diseases: BCO2, TULP2, and DGKQ. Our results both expand and refine the genetic spectrum of congenital glaucoma with important clinical implications.

Glaucoma

Glaucoma is a heterogeneous group of diseases characterised by cupping of the optic nerve head and visual-field damage. It is the most frequent cause of irreversible blindness worldwide. Progression usually stops if the intraocular pressure is lowered by 30-50% from baseline. Its worldwide age-standardised prevalence in the population aged 40 years or older is about 3·5%. Chronic forms of glaucoma are painless and symptomatic visual-field defects occur late. Early detection by ophthalmological examination is mandatory. Risk factors for primary open-angle glaucoma-the most common form of glaucoma-include older age, elevated intraocular pressure, sub-Saharan African ethnic origin, positive family history, and high myopia. Older age, hyperopia, and east Asian ethnic origin are the main risk factors for primary angle-closure glaucoma. Glaucoma is diagnosed using ophthalmoscopy, tonometry, and perimetry. Treatment to lower intraocular pressure is based on topical drugs, laser therapy, and surgical intervention if other therapeutic modalities fail to prevent progression.

Early Trabeculotomy Ab Externo in Treatment of Sturge-Weber Syndrome

PURPOSE

To evaluate the intermediate-term efficacy and safety of trabeculotomy in infant Sturge-Weber syndrome (SWS).

DESIGN

Retrospective cohort study.

METHODS

All SWS-induced glaucoma patients less than 12 months of age who underwent trabeculotomy at our Ophthalmology Department from August 2011 to March 2017 were reviewed. Baseline demographics, intraocular pressure (IOP), cup-to-disc ratio (C/D), and cornea diameters were noted before surgery. The IOP, success probabilities, and medication usage were recorded during follow-up until the last visit.

RESULTS

Overall, 34 eyes (32 patients) were included, with a median surgery age of 3 months and a median follow-up time of 15.5 months. The mean preoperative IOP, asymmetry between 2 eyes, cornea diameter, and median C/D were 21.5 ± 6.6 mm Hg, 10.1 ± 4.9 mm Hg, 12.6 ± 0.7 mm, and 0.65 (interquartile range [IQR]: 0.55, 0.80), respectively. The IOP was significantly reduced from the preoperative baseline at 1 week, 3 months, 6 months, 1 year, and 2 years after the surgery (P < .05). At the last follow-up, the cumulative proportions of overall and complete success were 86.6% and 66.0%, respectively. Complications included a transient shallow anterior chamber. Thirty of the 34 eyes had intraoperative hyphema, 27 of which lasted less than 3 days. No other complications were noted during the follow-up.

CONCLUSIONS

Compared to previous studies with a later diagnosis of glaucoma in SWS patients, better outcomes were achieved with an early diagnosis of glaucoma in SWS patients. Early trabeculotomy ab externo was safe and led to good intermediate-term surgical outcomes for early-onset glaucoma in SWS patients. Higher preoperative IOP and corneal edema were associated with a greater risk of surgery failure.

Primary congenital and developmental glaucomas

Glaucoma is the leading cause of irreversible blindness worldwide. Although most glaucoma patients are elderly, congenital glaucoma and glaucomas of childhood are also important causes of visual disability. Primary congenital glaucoma (PCG) is isolated, non-syndromic glaucoma that occurs in the first three years of life and is a major cause of childhood blindness. Other early-onset glaucomas may arise secondary to developmental abnormalities, such as glaucomas that occur with aniridia or as part of Axenfeld-Rieger syndrome. Congenital and childhood glaucomas have strong genetic bases and disease-causing mutations have been discovered in several genes. Mutations in three genes (CYP1B1, LTBP2, TEK) have been reported in PCG patients. Axenfeld-Rieger syndrome is caused by mutations in PITX2 or FOXC1 and aniridia is caused by PAX6 mutations. This review discusses the roles of these genes in primary congenital glaucoma and glaucomas of childhood.

Randomized Trial on Illuminated-Microcatheter Circumferential Trabeculotomy Versus Conventional Trabeculotomy in Congenital Glaucoma

PURPOSE

To compare 1-year outcomes of illuminated microcatheter-assisted circumferential trabeculotomy (IMCT) vs conventional partial trabeculotomy (CPT) for primary congenital glaucoma (PCG).

DESIGN

Randomized clinical trial.

METHODS

Forty eyes of 31 patients with unilateral or bilateral primary congenital glaucoma aged less than 2 years were randomized to undergo IMCT (20 eyes) or CPT (20 eyes). Primary outcome measure was intraocular pressure (IOP) reduction. The success criterion was defined as IOP ≤ 12 mm Hg without and with antiglaucoma medications (absolute success and qualified success, respectively).

RESULTS

The mean age of our study population was 8.35 ± 1.2 months. The mean preoperative IOP was 24.70 ± 3.90 mm Hg in the IMCT group and 24.60 ± 3.31 mm Hg in the CPT group. Both groups were comparable with respect to preoperative IOP, corneal clarity, corneal diameter, vertical cup-to-disc ratio, and refractive error. In the IMCT group, 360-degree cannulation was achieved in 80% (16/20) of eyes. For the IMCT group and CPT groups, respectively, the absolute success rates were 80% (16/20) and 60% (12/20) (P < .001) and qualified success rates were 90% (18/20) and 70% (14/20) (P < .001). Both procedures produced a statistically significant reduction in IOP, and eyes undergoing IMCT achieved a lower IOP than CPT group eyes at 12 months follow-up (9.5 ± 2.4 mm Hg and 11.7 ± 2.1 mm Hg, respectively, P < .001).

CONCLUSION

In primary congential glaucoma, illuminated microcatheter-assisted 360-degree circumferential trabeculotomy performed better than conventional partial trabeculotomy at 1 year follow-up and resulted in significantly lower IOP measurements.

Optimising keratoplasty for Peters' anomaly in infants using spectral-domain optical coherence tomography

PURPOSE

To present in vivo anterior segment optical coherence tomography (OCT) features of infants with Peters' anomaly obtained during presurgical examination under general anaesthesia, and to evaluate the impact of OCT features on surgical decision making.

METHODS

This is a single-centre, consecutive, observational case series including 44 eyes of 27 infants with Peters' anomaly (5-18 months) undergoing keratoplasty. Medical records of patients were reviewed retrospectively. Clinical features and OCT findings, along with their impact on surgical decision-making were analysed.

RESULTS

Of 27 patients, 10 had unilateral and 17 had bilateral disease. Two patients with mild disease (three eyes) had a posterior corneal defect with leukoma (2/27, 7.4%). Twenty patients (32 eyes) with iridocorneal adhesions were classified as having moderate Peters' anomaly (20/27, 74.1%) and five patients (nine eyes) with lenticulocorneal adhesions were classified as having severe Peters' anomaly (5/27, 18.5%). The range of angle closure, anterior chamber depth and maximum iridocorneal adhesion length (all p<0.001) were significantly different among groups, indicating that they might serve as novel OCT parameters for assessing the severity of Peters' anomaly. The surgical approach in seven patients (21.2%) was altered in response to intraoperative OCT findings, which provided information regarding the anatomical structure of the anterior chamber not provided by the surgical microscope. The use of OCT prevented unnecessary cataract surgeries in five patients.

CONCLUSIONS

Our study showed that information gained from OCT under anaesthesia allows surgeons to classify type and severity of Peters' anomaly and supports surgical decision making.

Acute Corneal Hydrops in Children with Primary Infantile Glaucoma: A Report of 31 Cases over 23 Years at the LVPEI

Purpose

Relatively little data exist regarding the outcomes of children with primary infantile glaucoma presenting with acute corneal hydrops. The aim of our study was to determine the surgical outcome of children of infantile glaucoma who presented with acute corneal hydrops.

Methods

In total, 38 eyes of 31 consecutive children of infantile glaucoma presented with acute corneal hydrops who underwent primary combined trabeculotomy-trabeculectomy (CTT) by a single surgeon from January 1990 to December 2012 at the LV Prasad Eye Institute (LVPEI), a tertiary eye care centre in Southern India were enrolled in this retrospective study. Primary outcome measures were intraocular pressure (IOP) control (IOP ≤ 16 mmHg under anaesthesia or IOP ≤ 21 mmHg without anaesthesia) and clearance of corneal edema. Secondary outcome measures were visual acuity (VA), corneal diameter, bleb appearance, intraoperative and postoperative complications.

Results

Mean age at presentation was 6.4 months (range, 2–11 months) and seven eyes (23%) had bilateral affliction. At presentation, all eyes (100%) had moderate to severe degree of corneal edema with a mean preoperative IOP of 25.6 ±5.1 mmHg. Postoperatively, the IOP reduced to 12.0 ± 3.8 mmHg (difference = -13.6, 95% CI = -15.7 to -11.5, t = -13.18, p<0.0001), and the percentage reduction in IOP was 53.05%. Preoperatively 83% of the eyes were on antiglaucoma medication, and postoperatively 2 eyes (5.3%) required 1 antiglaucoma medication for control of IOP. Preoperatively, corneal edema was present in all eyes and postoperatively it cleared in all of them. Significant myopic astigmatism was present in 28 eyes (74%), the commonest being compound myopic astigmatism (75%) followed by simple myopic astigmatism (21%). Normal VA (best-corrected VA; BCVA ≥ 20/60) was achieved in 44.4% of the eyes and 22.2% eyes had low vision (BCVA, <20/60 to 20/400). Complete success (IOP control and clearance of corneal oedema) was obtained in 94.7% eyes. There were no significant intraoperative or postoperative complications. Two thirds of the patients showed low, elevated functional filtering bleb. No patient had any bleb leak, blebitis or bleb related endophthalmitis. The median follow-up was 36 months (range 2–228 months).

Conclusions

Primary CTT is safe and effective in controlling IOP, resulting in complete clearance of corneal edema with modest visual improvement in children of infantile glaucoma presenting with acute corneal hydrops. The outcome of the study will have a positive impact on counseling the parents preoperatively.

Scleral and choroidal volume in relation to axial length in infants with retinoblastoma versus adults with malignant melanomas or end-stage glaucoma

PURPOSE

To measure scleral and choroidal volume in eyes of Chinese, and to assess associations with age and axial length.

METHODS

We histomorphometrically examined globes from infants and adults which had been enucleated due to retinoblastoma, uveal melanoma, or absolute painful glaucoma. Thickness of sclera and choroid were measured, and volumes were calculated.

RESULTS

The study included 225 globes (mean axial length: 24.6 ± 4.2 mm; range:17.0-35.7 mm; mean age: 30.4 ± 22.6 years; range: 1-83 years). Mean computed scleral volume was 648 ± 136 mm(3). Scleral volume in children aged <5 years significantly increased with longer axial length (P = 0.001; correlation coefficient r: 0.42) and older age (P = 0.003; r: 0.39) in univariate analysis. In multivariate analysis within the group of children aged ≤2 years, larger scleral volume increased with longer axial length (P = 0.04; standardized correlation coefficient beta: 0.32; correlation coefficient B: 21.6; 95 % confidence interval (CI): 0.52, 42.7) and showed a statistically non-significant tendency to increase with older age (P = 0.06;b eta: 0.30; B: 56.9; 95% CI: -1.5,115). In individuals aged ≥ 5 years, scleral volume was not significantly associated with axial length (P = 0.75) or age (P = 0.13). Mean choroidal volume as measured and calculated in 95 individuals (age: 16-81 years) was 44.1 ± 14.1 mm(3), and was not significantly associated with age (P = 0.47; r: -0.08) or axial length (P = 0.83; r: -0.02).

CONCLUSIONS

This study on children eyes with retinoblastoma and adult eyes with malignant melanomas or end-stage glaucoma suggests that primary eye growth up to an age of 2 years is associated with an increase in scleral volume. After the age of 2 years, scleral volume and choroidal volume remain unchanged, leading to scleral and choroidal thinning with longer axial length, in particular at the posterior pole.