Update in Genetics and Surgical Management of Primary Congenital Glaucoma

Novel compound heterozygous variants in LTBP2 associated with relative anterior microphthalmos

PURPOSE

Relative anterior microphthalmos (RAM) is a rare congenital defect associated with severe vision impairment that is primarily caused by genetic alterations. The purpose of this study was to identify the causative genetic variants in two Chinese families with RAM with an autosomal recessive inheritance pattern.

METHODS

DNA samples were obtained from two probands and their family members. Targeted next-generation sequencing (NGS) was used to screen 425 genes associated with inherited eye diseases to identify possible disease-causing variants in the two patients. Sanger sequencing was subsequently used to validate the results in both families.

RESULTS

The targeted NGS panel identified potentially causative novel variants of the latent transforming growth factor beta binding protein 2 (LTBP2) gene in the two RAM families: a missense variant (c.2771C > T; p.Ala924Val) and an intronic variant (c.4582 + 9A > G) in Family A and a different missense variant (c.5239C > A; p.Arg1747Ser) and a synonymous variant (c.951G > A; p.Pro317Pro) in Family B. These four novel variants all cosegregated with the disease phenotype.

CONCLUSION

To our knowledge, this is the first study to report novel LTBP2 gene variants related to RAM. Considering the importance of LTBP2 in ocular development, we provide initial insights into the potential pathogenic mechanisms of LTBP2 in RAM.

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.

Clinical value of cognitive behavioral nursing model to patients with congenital glaucoma

BACKGROUND

There have been studies on the use of cognitive behavioral nursing intervention (CBNI) but the main subjects were patients with secondary glaucoma and there are fewer studies on the care of congenital glaucoma.

OBJECTIVE

To explore the clinical value of cognitive behavioral nursing model in patients with congenital glaucoma.

METHODS

One hundred and fifty-three postoperative patients with congenital glaucoma treated in our hospital between January 2021 and December 2022 were prospectively selected for the study and randomly divided into a control group (n= 77) and an observation group (n= 76). The control group was given routine nursing, and the observation group was given cognitive behavioral nursing mode on the basis of the control group. Anxiety self-assessment scale (SAS), depression self-assessment scale (SDS), Connor-Davidson toughness scale, and treatment adherence evaluation scale were used to evaluate the psychological state, mental toughness, treatment adherence, treatment effect and nursing care satisfaction in the two groups before and after 2 weeks of intervention. The efficacy of the treatment was also assessed by determining the visual acuity (VA), intraocular pressure (IOP), and mean defective (MD) value of the visual field of the two groups of patients.

RESULTS

After nursing, the SDS score (46.33 ± 6.16 versus 53.21 ± 5.94) and SAS score (44.41 ± 5.6 versus 52.82 ± 6.31) in the observation group were lower than those in the control group (P< 0.05). The scores of optimism (11.55 ± 1.90 versus 8.20 ± 1.95), self-improvement (22.05 ± 3.60 versus 17.60 ± 4.30), tenacity (37.45 ± 3.10 versus 28.90 ± 4.55) and total score (71.35 ± 8.00 versus 56.85 ± 8.50) in the observation group were higher than those in the control group (P< 0.05). After care, the VA of the observation group (0.95 ± 0.22) was greater than that of the control group (0.84 ± 0.16), and the IOP (14.25 ± 0.58 versus 15.89 ± 0.67) and the MD (5.42 ± 0.46 versus 6.68 ± 0.49) of the observation group were less than that of the control group. The difference between the two groups was statistically significant (P< 0.05). The compliance (96.05% versus 85.71%) and nursing satisfaction (96.10% versus 85.71%) of the observation group were higher than those of the control group (P< 0.05).

CONCLUSION

Cognitive-behavioural nursing care for glaucoma patients can improve patients' mental toughness, improve visual acuity, reduce intraocular pressure and mean visual field defect values, and have a positive effect on enhancing patients' treatment adherence and nursing satisfaction.

Genetic Aspects of Glaucoma: An Updated Review

Glaucoma is a group of diverse diseases characterized by cupping of the optic nerve head due to the loss of retinal ganglion cells. It is the most common cause of irreversible blindness throughout the world; therefore, its timely diagnosis and early detection through an ophthalmological examination are very important. We, herein, present the information on the epidemiology, pathophysiology, clinical diagnosis, and treatment of glaucoma. We also emphasize the investigations of the last decades that have allowed identifying numerous genes and susceptibility genetic factors. We have also described in detail the genes whose mutations cause or contribute to the development of the disease.

Genetics and Glaucoma: the state of the art

Glaucoma is the second leading cause of irreversible blindness worldwide. Although genetic background contributes differently to rare early-onset glaucoma (before age 40) or common adult-onset glaucoma, it is now considered an important factor in all major forms of the disease. Genetic and genomic studies, including GWAS, are contributing to identifying novel loci associated with glaucoma or to endophenotypes across ancestries to enrich the knowledge about glaucoma genetic susceptibility. Moreover, new high-throughput functional genomics contributes to defining the relevance of genetic results in the biological pathways and processes involved in glaucoma pathogenesis. Such studies are expected to advance significantly our understanding of glaucoma's genetic basis and provide new druggable targets to treat glaucoma. This review gives an overview of the role of genetics in the pathogenesis or risk of glaucoma.

Understanding the complex genetics and molecular mechanisms underlying glaucoma

Glaucoma is the leading cause of irreversible blindness worldwide. Currently the only effective treatment for glaucoma is to reduce the intraocular pressure, which can halt the progression of the disease. Highlighting the importance of identifying individuals at risk of developing glaucoma and those with early-stage glaucoma will help patients receive treatment before sight loss. However, some cases of glaucoma do not have raised intraocular pressure. In fact, glaucoma is caused by a variety of different mechanisms and has a wide range of different subtypes. Understanding other risk factors, the underlying mechanisms, and the pathology of glaucoma might lead to novel treatments and treatment of underlying diseases. In this review we present the latest research into glaucoma including the genetics and molecular basis of the disease.

Visco-Circumferential-Suture-Trabeculotomy Versus Rigid-Probe Viscotrabeculotomy in Neonatal-Onset Primary Congenital Glaucoma

PRCIS

Angle procedures are safe and relatively effective for neonatal onset PCG. Watchful delay in intervention to close to the second month of life is helpful in ensuring diagnosis and making surgery more successful and easier.

PURPOSE

The purpose of this study was to compare the surgical outcomes of visco-circumferential-suture-trabeculotomy (VCST) to rigid-probe double-entry viscotrabeculotomy (DEVT) and rigid-probe single-entry viscotrabeculotomy (SEVT) in infants with neonatal-onset primary congenital glaucoma (PCG).

DESIGN

This was a retrospective chart review.

PATIENTS AND METHODS

Retrospective chart review of 64 eyes of 64 infants with neonatal-onset PCG referred to Mansoura Ophthalmic Center in Mansoura, Egypt between February 2008 and November 2018. Study groups included VCST, DEVT, and SEVT, and follow-up covered 4 postoperative years. Complete (qualified) success was defined as intraocular pressure (IOP) ≤18 mm Hg and with 35% IOP reduction from baseline without (with) IOP-lowering medications or further surgical interventions, and without any sign of progression in corneal diameter, axial length, or optic disc cupping and without visual devastating complications.

RESULTS

The mean±SD age at presentation and at the surgery of the study children was 3.63±1.74 and 55.23±1.60 days, respectively. The mean±SD IOP and cup/disc ratio of all study eyes at presentation and at final follow-up were 34.91±0.82 mm Hg and 0.70±0.09 and 17.04±0.74 mm Hg and 0.63±0.08, respectively. Complete success was achieved in 54.5%, 43.5%, and 31.6% in the VCST, DEVT, and SEVT groups, respectively. A self-limited hyphema was the commonest complication in all groups.

CONCLUSIONS

Angle procedures are safe and marginally effective for the surgical treatment of neonatal-onset PCG, bringing IOP under control for at least 4 years of follow-up. Circumferential trabeculotomy as a first-line treatment has more favorable outcomes than rigid-probe SEVT. Rigid-probe viscotrabeculotomy offers an alternative to the noncompleted circumferential procedure.

Glaucoma Associated with Anterior Segment Dysgenesis in Dogs and Cats

Reports of glaucoma associated with anterior segment dysgenesis in dogs and cats are rare. Anterior segment dysgenesis is a sporadic, congenital syndrome with a range of anterior segment anomalies that may or may not result in congenital or developmental glaucoma within the first years of life. Specifically, the anterior segment anomalies that put the neonatal or juvenile dog or cat at high risk for the development of glaucoma are filtration angle and anterior uveal hypoplasia, elongated ciliary processes, and microphakia.

Outcomes of Non-Penetrating Deep Sclerectomy for Primary Congenital Glaucoma Performed by Experienced versus Trainee Surgeons: A Cohort Study

Purpose

To compare the outcomes of non-penetrating deep sclerectomy (NPDS) for primary congenital glaucoma (PCG) performed by experienced vs trainee surgeons.

Patients and Methods

This retrospective cohort study was conducted in 2022 in Saudi Arabia. Consultants (Gr-1) and trainee pediatric ophthalmologists (Gr-2) performed NPDS on pediatric patients with PCG. Success was defined as an intraocular pressure (IOP) less than 21 mmHg at 6 months after surgery. Complications, glaucoma medications, and additional procedures were also observed in the two groups.

Results

Gr-1 and Gr-2 operated on 14 and 39 eyes with PCG, respectively. The absolute success rates were 90.9% (95% confidence interval [CI]: 73.9, 100) in Gr-1 and 96.7% (95% CI: 90.2, 100) in Gr-2 (odds Ratio=1.1; 95% CI: 0.87, 1.3; P=0.54). Survival analysis suggested that the failure rate in the first 6 months after NPDS was not significantly different between the two groups (hazard ratio=1.45; 95% CI: 0.13, 16.0; P=0.767). The complications included hypotony (2 cases), vitreous hemorrhage (1 case), and total flap penetration (1 case). Only one eye in Gr-2 needed glaucoma medication after surgery. There was no significant difference in the success rates of one surgeon before and after training (P=0.43). The age (P=0.59) and sex (P=0.77) of patients, type of surgeon (P=0.94), and preoperative IOP (P=0.59) were not significant predictors of a stable IOP at 6 months after NPDS.

Conclusion

At 6 months after NPDS surgery performed by experienced and trainee pediatric ophthalmologists, the outcomes (stabilization of IOP) were similar between the two groups.

Efficacy and safety of the PreserFlo implant with mitomycin C in childhood glaucoma after previous failed glaucoma surgeries

PURPOSE

This study aims to evaluate the efficacy and safety of the PreserFlo MicroShunt (Santen, Osaka, Japan) in lowering intraocular pressure (IOP) in childhood glaucoma patients with previous failed glaucoma surgeries.

METHODS

This is a prospective case review of consecutive PreserFlo procedures performed in childhood glaucoma patients after failed surgeries. Age, sex, diagnosis, and previous glaucoma surgeries, as well as visual acuity, IOP, and treatment in the preoperative visit and all follow-up visits were collected. Outcome measures included IOP reduction from baseline, mean IOP change from baseline at month 6, medication use at 6 months, complications, adverse events, and need for further procedures.

RESULTS

Fourteen patients were included, 8 (57%) males and 6 (43%) females; the mean age was 27.5 ± 13.5 years. Nine patients (64%) had at least two trabeculectomies, and 6 patients (43%) had at least one trabeculectomy and a glaucoma drainage implant. The mean IOP change from baseline was 11.3 ± 4.9 mmHg at 12 months. At 12 months, 12 patients (86%) presented ≥ 20% IOP lowering from baseline, and 11 patients (79%) presented ≥ 30%. The mean medication count decreased from 3.9 ± 0.7 (baseline) to 0.7 ± 1.3 (12 months). No intraoperative complications were reported. No adverse events were noted. No secondary filtration surgery was required, although bleb needling was required in one case, 1 month after the surgery.

CONCLUSIONS

PreserFlo with MMC can be used successfully to treat uncontrolled IOP in childhood glaucoma cases with previous failed surgeries. Larger studies with longer follow-up are needed to further explore the role of the device in resistant childhood glaucoma cases.

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.

Minimally invasive glaucoma surgery in childhood glaucoma

PURPOSE OF REVIEW

Minimally invasive glaucoma surgery (MIGS) has been shown to be safe and effective in treatment of mild to moderate glaucoma in adults, but reports in childhood glaucoma are limited. We review the available data concerning MIGS and discuss its potential role in childhood glaucoma management.

RECENT FINDINGS

Ab interno counterparts to circumferential ab externo trabeculotomy such as gonioscopy-assisted transluminal trabeculotomy (GATT) and Trab360 show promise in treatment of primary glaucomas as reported in a few retrospective case series. Kahook Dual Blade (KDB) and Trabectome have demonstrated mixed results in few published case reports in children. Small case series and reports suggest that the Xen gel stent can be a safer alternative to traditional filtration surgery, though data on long-term implant and bleb stability are unavailable. Newer devices are being investigated and early results are encouraging.

SUMMARY

GATT and Trab360 seem to be safe, effective methods of achieving circumferential trabeculotomy in childhood glaucoma. KDB, Trabectome, and Xen gel stent have shown some success in selected cases with short-term follow-up. Surgeons must determine the risks and benefits of MIGS over more established methods of intraocular pressure reduction for each individual child. Further research is needed to validate initial findings regarding MIGS in childhood glaucoma.

Surgical Outcomes of Visco-Circumferential-Suture-Trabeculotomy Versus Rigid Probe Trabeculotomy in Primary Congenital Glaucoma: A 3-Year Randomized Controlled Study

PURPOSE

The aim was to compare the long-term surgical outcomes of visco-circumferential-suture-trabeculotomy (VCST) and rigid probe viscotrabeculotomy (VT) in patients with primary congenital glaucoma (PCG).

PATIENTS AND METHODS

The study was conducted on 84 (47 right) eyes of 49 (32 males) children PCG to the pediatric ophthalmology unit of Mansoura Ophthalmic Center of Mansoura University, Egypt between 2015 and 2018. An initial office examination was followed by an examination under general anesthesia to establish the diagnosis of PCG. The children were then scheduled for surgery and the eyes randomly assigned to VCST or VT. Follow-up visits were scheduled at the first day, first week, first, and third months and then every 3 months for 1 year.

RESULTS

The mean±SD age of the study children at presentation was 4.8±2.1 and 4.9±1.7 months in the VCST and the VT groups, respectively (P=0.827). The mean±SD preoperative intraocular pressure (IOP) was 29.13±3.3 and 29.89±3.2 mm Hg in the VCST and VT groups, respectively (P=0.292) and 11.9±1.3 and 13.8±1.2 mm Hg at the end of 36 moths of follow-up (P<0.001). The IOP at all follow-up time points (except at the third month, P=0.924) was statistically significantly less in the VCST group than in the VT group (at week 1, month 1, 6, 9, 12, 18, 24, 30, and 36 the P<0.001). The cumulative probability of success was 100%, 95%, 90%, and 90%, respectively in VSCT and 100%, 72.7%, 97.7%, 90.9%, and 84% in VT at 12, 24, 30, and 36 months.

CONCLUSIONS

Both VCST and VT were effective and safe for lowering the IOP in PCG with VCST providing a marginal advantage over VT.

Ab interno 180-degree trabeculectomy with a dual blade in a patient with refractory primary congenital glaucoma

A 13-year-old female patient with refractory primary congenital glaucoma (PCG) in the right eye who had a history of multiple glaucoma operations underwent ab interno 180-degree trabeculectomy with the Kahook Dual Blade (KDB) targeting the nasal and inferior angles. On postoperative day 1, the intraocular pressure (IOP) of the right eye reduced from 43 to 15 mmHg while on medical therapy. The patient maintained this IOP level throughout the 6-month follow-up. Ab interno KDB trabeculectomy targeting both nasal and inferior angles may be an effective and safe procedure for the treatment of PCG even in eyes with a history of previously failed glaucoma procedures.