Causes of blindness and severe visual impairment in children in Chile

Long-term outcome and determinants of primary pediatric cataract surgery

PURPOSE

This study aimed to evaluate the long-term outcomes of primary pediatric cataract surgery and to identify determinants of success and recommendations to improve the care of patients with pediatric cataracts.

METHODS

A cohort, retrospective study of cases who were operated as primary pediatric cataract surgery at King Khaled Eye Specialist Hospital. Patients who are 4 years old or younger and underwent primary cataract surgery with at least 3-year follow-up were enrolled in this study. Preoperative and postoperative evaluations were performed to determine the surgery outcomes.

RESULTS

Two hundred and two eyes of 119 patients were enrolled in the study. Seventy percentage of the patients were diagnosed with bilateral cataracts and 30% with unilateral cataracts. Postoperative evaluation showed that 20% of the patients had best corrected visual acuity of 20/30 or better, 25% had 20/40-20/50, 20% had 20/60-20/80, and 29% had 20/100 or less, 6% as fixate and follow. In addition, the mean spherical equivalent was 1.50D. Amblyopia was present in 120 eyes. Fourteen percentage showed a significant myopic shift of more than -4.00D and it was more in eyes with primary intraocular lens (IOL) implantation. Glaucoma was reported in 19% of the patients.

CONCLUSION

There was a significant postoperative myopic shift and it was more in eyes with primary IOL implantation. Glaucoma was the most common reported postoperative complication. The presence of strabismus and nystagmus may affect the visual outcomes. Early intervention might reduce the incidence of amblyopia.

Visual Field Testing Frequency and Associations in Children With Glaucoma

PRCIS

Children with glaucoma had an average of 1.3 visual field tests per year. Self-reported black and multiracial patients had lower visual field testing rates, whereas older children with better visual acuity had more frequent testing.

PURPOSE

To evaluate frequency of visual field (VF) testing in children with glaucoma and identify characteristics associated with VF frequency.

METHODS

A retrospective cohort study of 82 children 6-18 years of age with glaucoma seen between August 2018 and May 2023. Patients were divided into those who had ≥1 VF test (303 VF tests of 61 children) and 0 VFs (21 children). Eyes were excluded if best corrected visual acuity (BCVA) was counting fingers or worse. Characteristics obtained included age, self-reported race and ethnicity, sex, primary language, glaucoma diagnosis, distance to provider, office visit frequency, follow-up compliance, insurance type, and BCVA. The main outcome measure was VF testing frequency.

RESULTS

Among children with ≥1 VF test, mean age at first VF was 11.8±2.8 years, mean number of VF/year was 1.3±0.8, and 44.9% of all VFs were reliable. Thirty nine percent of patients underwent <1 VF/year, 45.9% ≥1 to <2 VFs/year, and 14.8% ≥2 VF/year. Children who were black or multiracial had significantly lower VF testing frequency [estimated difference (ED) -1.2 (95% CI, -2.0 to -0.4, P =0.002) and ED -1.3 (95% CI, -2.2 to -0.3, P =0.008), respectively]. Better visual acuity and greater office visit frequency were significantly associated with higher VF testing frequency [ED 0.052 (95% CI, 0.001-0.103, P =0.045) and ED 0.2 (95% CI, 0.1-0.3, P <0.001), respectively].

CONCLUSIONS

Most children had between 1 and 2 VF/year, although less than half of all VFs were reliable. Ophthalmologists should consider barriers to care in glaucoma monitoring.

Comparison of Efficacy of Micropulse and Continuous Wave Cyclophotocoagulation in Patients With Pediatric Glaucoma

PRCIS

Both micropulse (MP-CPC) and continuous wave (CW-CPC) cyclophotocoagulation exhibited short-term effectiveness in lowering IOP, followed by reversion to near baseline levels 12 months after laser treatment.

OBJECTIVE

To determine and compare the effectiveness and safety of MP-CPC and CW-CPC in patients diagnosed with pediatric glaucoma.

METHODS

A retrospective cohort study was conducted on a total of 28 patients (81 eyes) diagnosed with pediatric glaucoma either undergoing MP-CPC or CW-CPC. Intraocular pressure (IOP) measurements, number of glaucoma medications, and the onset of complications were collected at baseline, 1-month, 3-month, 6-month, and 12-month intervals. Success rate (SR) was defined as eyes achieving IOP ≤21 mm Hg and ≥5 mm Hg and a 20% reduction in IOP at the last follow-up visit.

RESULTS

All patients either undergoing MP-CPC or CW-CPC were matched for age (mean ± SD; 1.76 ± 1.69 vs 1.56 ± 2.49 y). Patients undergoing MP-CPC had significant decreases in IOP from baseline IOP at 1, 3, and 6 months with a 22% SR at 12 months. CW-CPC had a significant decrease in IOP from baseline IOP at all follow-ups, with a 27% SR at 12 months. At the 12-month follow-up, the CW-CPC cohort exhibited a significantly larger overall drop in IOP when compared with the MP-CPC cohort, (7.99 ± 7.95 vs 1.78 ± 6.89, P < 0.05); however, the difference in SR between treatment groups (27% vs 22%) at 12 months was not significant ( P > 0.05). Complications were minimal for both groups.

CONCLUSION

Both MP-CPC and CW-CPC exhibited short-term effectiveness in lowering IOP, followed by reversion to near baseline levels 12 months after laser treatment. Both MP-CPC and CW-CPC exhibited similar SR at 12 months, 22% and 27% respectively.

Microcatheter-Assisted Circumferential Trabeculotomy After Failed Glaucoma Surgeries in Childhood Glaucoma

PURPOSE

To evaluate the outcomes of microcatheter-assisted trabeculotomy (MAT) in childhood glaucoma (primary congenital glaucoma [PCG], juvenile open-angle glaucoma [JOAG], and secondary childhood glaucoma [SCG]) after failed glaucoma surgery.

DESIGN

Retrospective interventional case series.

METHODS

Patients with childhood glaucoma who underwent MAT after failed glaucoma surgery with at least 12 months of follow-up were evaluated. Pre- and postoperative intraocular pressure (IOP) and the number of glaucoma medications were recorded and compared. Success was defined as an IOP ≤21 mm Hg with or without glaucoma medication. Analysis of variance was used to compare the glaucoma subgroups.

RESULTS

Forty-five eyes (42 patients) with a median follow-up period of 19 months were included. The median age at the time of MAT was 10 (range, 0.8-33) years. The mean number of previous surgeries was 1.3 ± 0.5. The IOP had significantly reduced from baseline in all PCG, JOAG, and SCG patients (27.9 ± 4.5 vs 16.3 ± 8.0 mm Hg, P = .001; and 30.8 ± 9.4 vs 13.5 ± 3.0 mm Hg, P < .001; and 31.5 ± 7.1 vs 16.5 ± 5.3 mm Hg, P = .001, respectively). Fewer glaucoma medications were needed after MAT in all 3 groups (each P < .001). At the last visit, the total success rates in PCG, JOAG, and SCG were 93.8%, 100%, and 88.9%, respectively. No severe complications were observed.

CONCLUSION

MAT can effectively manage PCG, JOAG, and SCG after failed surgeries, providing successful outcomes and no serious complications. Following failed glaucoma surgeries, MAT may offer these patients with childhood glaucoma an excellent opportunity to achieve IOP control.

Deep-learning approach to detect childhood glaucoma based on periocular photograph

Childhood glaucoma is one of the major causes of blindness in children, however, its diagnosis is of great challenge. The study aimed to demonstrate and evaluate the performance of a deep-learning (DL) model for detecting childhood glaucoma based on periocular photographs. Primary gaze photographs of children diagnosed with glaucoma with appearance features (corneal opacity, corneal enlargement, and/or globe enlargement) were retrospectively collected from the database of a single referral center. DL framework with the RepVGG architecture was used to automatically recognize childhood glaucoma from photographs. The average receiver operating characteristic curve (AUC) of fivefold cross-validation was 0.91. When the fivefold result was assembled, the DL model achieved an AUC of 0.95 with a sensitivity of 0.85 and specificity of 0.94. The DL model showed comparable accuracy to the pediatric ophthalmologists and glaucoma specialists in diagnosing childhood glaucoma (0.90 vs 0.81, p = 0.22, chi-square test), outperforming the average of human examiners in the detection rate of childhood glaucoma in cases without corneal opacity (72% vs. 34%, p = 0.038, chi-square test), with a bilateral corneal enlargement (100% vs. 67%, p = 0.03), and without skin lesions (87% vs. 64%, p = 0.02). Hence, this DL model is a promising tool for diagnosing missed childhood glaucoma cases.

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.

Comparative efficacies of 13 surgical interventions for primary congenital glaucoma in children: a network meta-analysis of randomized clinical trials

BACKGROUND

Timely and proper intraocular pressure (IOP) management is vital to the prevention of visual impairment in children with primary congenital glaucoma (PCG). Although various surgical interventions have been proposed, no well-founded evidence exists on their comparative efficacies. We aimed to compare the efficacies of surgical interventions for PCG.

METHODS

We searched relevant sources up to 4 April 2022. Randomized controlled trials (RCTs) entailing surgical interventions for PCG in children were identified. A network meta-analysis (NMA) was performed, comparing 13 surgical interventions: Conventional partial trabeculotomy ([CPT] control), 240-degree trabeculotomy, Illuminated microcatheter-assisted circumferential trabeculotomy (IMCT), Viscocanalostomy, Visco-circumferential-suture-trabeculotomy, Goniotomy, Laser goniotomy, Kahook dual blade ab-interno trabeculectomy, Trabeculectomy with mitomycin C, Trabeculectomy with modified scleral bed, Deep sclerectomy, Combined trabeculectomy-trabeculotomy with mitomycin C, and Baerveldt implant. The main outcomes were mean IOP reduction and surgical success rate at postoperative 6 months. The mean differences (MDs) or odds ratios (ORs) were analyzed by a random-effects model, and the efficacies were ranked by P -score. We appraised the RCTs using the Cochrane risk-of-bias (ROB) tool (PROSPERO: CRD42022313954).

RESULTS

Sixteen RCTs were eligible for NMA, including 710 eyes of 485 participants and 13 surgical interventions, which formed a network of 14 nodes comprising both single interventions and intervention combinations. IMCT was superior to CPT in both IOP reduction [MD (95% CI): -3.10 (-5.50 to -0.69)] and surgical success rate [OR (95% CI): 4.38 (1.61-11.96)]. The MD and OR comparing the other surgical interventions and intervention combinations with CPT were not statistically significant. The P -scores ranked IMCT as the most efficacious surgical intervention in terms of success rate ( P -score =0.777). Overall, the trials had a low-to-moderate ROB.

CONCLUSION

This NMA indicated that IMCT is more effective than CPT and might be the most efficacious of the 13 surgical interventions for management of PCG.

Possibility of genetic therapy for inherited retinal conditions

OBJECTIVE

To evaluate the possibility of gene therapy in patients with inherited ocular conditions and established genetic diagnosis. The secondary objectives were to determine the genetic diagnostic rate and to update the list of genes for which there are ongoing clinical trials or preclinical studies that could allow for gene therapy.

METHODS

Observational, retrospective, multicentric study of 177 patients with inherited ocular conditions that underwent genetic testing.

RESULTS

Of 177 patients with genetic testing, 146 were enrolled for this study. Disease-causing variants were identified in 117 patients (variant detection rate of 80.1%). Pathogenic variants were found in 47 genes, with ABCA4 being the most common gene (17.9%), followed by CRB1 (11.9%). 64.1% of patients with a genetic diagnosis have a variant in genes for which gene therapy has been studied and only 40.1% have a variant in genes with studies for gene therapy in clinical phase.

CONCLUSIONS

Genetic testing has opened new horizons in the management of patients with hereditary ocular diseases. About two-thirds of the patients had pathogenic variants in genes for which gene therapy has been evaluated. However, many studies are in the pre-clinical phase. The expectations of patients undergoing genetic study and their families should be managed accordingly.

Carrier Status for p.Gly61Glu and p.Arg368His CYP1B1 Mutations Causing Primary Congenital Glaucoma in Iran

Purpose

To estimate carrier frequencies of CYP1B1 mutations p.Gly61Glu and p.Arg368His, respectively, in Talesh and the east of Guilan province in Iran with a maximum error of 2%. Previously, it was shown that these CYP1B1 mutations may be relatively prevalent in these regions.

Methods

Population-based screenings were performed. DNA was extracted from saliva samples of 1036 individuals from Talesh and 3029 individuals from the east of Guilan. P.Gly61Glu and p.Arg368His screenings were performed, respectively, by RFLP and ARMS-based PCR protocols. For confirmation, the DNA of individuals with mutations was sequenced using the Sanger protocol.

Results

Nine individuals from Talesh (0.86%; 95%CI: 0.45–1.64%) carried the p.Gly61Glu mutation, and 73 from the east of Guilan (2.41%; 95%CI: 1.91–3.04%) carried p.Arg368His. There was no significant difference in frequencies between urban and rural regions of the various cities, nor among four cities within the east of Guilan.

Conclusion

The frequencies of p.Gly61Glu carriers in Talesh and of p.Arg368His carriers in the east of Guilan were within the 95% confidence interval of a previous study based on screenings of fewer individuals. The reliability of the recent estimates is higher, as the confidence interval for p.Gly61Glu decreased from 6.5% to 1.19% and the interval for p.Arg368His decreased from 4% to 1.13%. Based on the new findings, the maximum expected frequency of p.Gly61Glu carriers in Talesh is 1.64%, and of p.Arg368His carriers in the east of Guilan is 3%. The need for performing premarital screenings in the respective cities can be evaluated.

Surgical interventions for primary congenital glaucoma

BACKGROUND

Primary congenital glaucoma (PCG) is an optic neuropathy with high intraocular pressure (IOP) that manifests within the first few years of a child's life and is not associated with other systemic or ocular abnormalities. PCG results in considerable morbidity even in high-income countries.

OBJECTIVES

To compare the effectiveness and safety of different surgical techniques for PCG.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2020, Issue 4); Ovid MEDLINE; Embase.com; PubMed; metaRegister of Controlled Trials (mRCT) (last searched 23 June 2014); ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We did not use any date or language restrictions in the electronic search. We last searched the electronic databases on 27 April 2020.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and quasi-RCTs comparing different surgical interventions in children under five years of age with PCG.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology.

MAIN RESULTS

We included 16 trials (13 RCTs and three quasi-RCTs) with 587 eyes in 446 children. Eleven (69%) trials were conducted in Egypt and the Middle East, three in India, and two in the USA. All included trials involved children younger than five years of age, with follow-up ranging from six to 80 months. The interventions compared varied across trials. Three trials (on 68 children) compared combined trabeculotomy and trabeculectomy (CTT) with trabeculotomy. Meta-analysis of these trials suggests there may be little to no evidence of a difference between groups in mean IOP (mean difference (MD) 0.27 mmHg, 95% confidence interval (CI) -0.74 to 1.29; 88 eyes; 2 studies) and surgical success (risk ratio (RR) 1.01, 95% CI 0.90 to 1.14; 102 eyes; 3 studies) at one year postoperatively. We assessed the certainty of evidence as very low for these outcomes, downgrading for risk of bias (-1) and imprecision (-2). Hyphema was the most common adverse outcome in both groups (no meta-analysis due to considerable heterogeneity; I² = 83%). Two trials (on 39 children) compared viscotrabeculotomy to conventional trabeculotomy. Meta-analysis of 42 eyes suggests there is no evidence of between groups difference in mean IOP (MD -1.64, 95% CI -5.94 to 2.66) and surgical success (RR 1.11, 95% CI 0.70 to 1.78) at six months postoperatively. We assessed the certainty of evidence as very low, downgrading for risk of bias and imprecision due to small sample size. Hyphema was the most common adverse outcome (38% in viscotrabeculotomy and 28% in conventional trabeculotomy), with no evidence of difference difference (RR 1.33, 95% CI 0.63 to 2.83). Two trials (on 95 children) compared microcatheter-assisted 360-degree circumferential trabeculotomy to conventional trabeculotomy. Meta-analysis of two trials suggests that mean IOP may be lower in the microcatheter group at six months (MD -2.44, 95% CI -3.69 to -1.19; 100 eyes) and at 12 months (MD -1.77, 95% CI -2.92 to -0.63; 99 eyes); and surgical success was more likely to be achieved in the microcatheter group compared to the conventional trabeculotomy group (RR 1.59, 95% CI 1.14 to 2.21; 60 eyes; 1 trial at 6 months; RR 1.54, 95% CI 1.20 to 1.97; 99 eyes; 2 trials at 12 months). We assessed the certainty of evidence for these outcomes as moderate due to small sample size. Hyphema was the most common adverse outcome (40% in the microcatheter group and 17% in the conventional trabeculotomy group), with greater likelihood of occurring in the microcatheter group (RR 2.25, 95% CI 1.25 to 4.04); the evidence was of moderate certainty due to small sample size (-1). Of the nine remaining trials, no two trials compared the same two surgical interventions: one trial compared CTT versus CTT with sclerectomy; three trials compared various suturing techniques and adjuvant use including mitomycin C, collagen implant in CTT; one trial compared CTT versus Ahmed valve implant in previously failed surgeries; one trial compared CTT with trabeculectomy; one trial compared trabeculotomy to goniotomy; and two trials compared different types of goniotomy. No trials reported quality of life or economic data. Many of the included trials had limitations in study design, implementation, and reporting, therefore the reliability and applicability of the evidence remains unclear.

AUTHORS' CONCLUSIONS

The evidence suggests that there may be little to no evidence of difference between CTT and routine conventional trabeculotomy, or between viscotrabeculotomy and routine conventional trabeculotomy. A 360-degree circumferential trabeculotomy may show greater surgical success than conventional trabeculotomy. Considering the rarity of the disease, future research would benefit from a multicenter, possibly international trial, involving parents of children with PCG and with a follow-up of at least one year.

Biometric changes in Indian pediatric cataract and postoperative refractive status

Purpose:

To prospectively evaluate the biometric changes in Indian pediatric cataract and postoperative refractive status.

Methods:

A total of 147 patients were recruited into three groups: age <6 months, age between 7 months and 18 months, and age between 19 and 60 months and prospectively observed for 6 months. Exclusion criteria were preterm birth, microphthalmia, microcornea, megalocornea, uveitis, glaucoma, and traumatic or complicated cataract. Axial length and keratometry, the primary outcome measures, were taken preoperatively under general anesthesia before surgery. These children were followed up for 6 months to look for refractive and biometric changes. T-test and linear regression with the logarithm of independent variables were done.

Results:

All unilateral cataractous eyes (n = 25) and randomly selected bilateral cases (n = 122) were included in the analysis, for a total of 147 eyes. Mean age was 17.163 ± 13.024 months; axial length growth was 0.21, 0.18, 0.06 mm/month, and keratometry decline was 0.083, 0.035, 0.001 D/month in age groups 0–6, 7–18, and 19–60 months, respectively. The visual acuity improved in log MAR from 1.020 to 0.745 at 6 months postoperatively. There was statistically significant (Spearman's correlation coefficient = –0.575, P < 0.001) between age and postoperative refraction. There were no intraocular lens (IOL)-related complications seen in the immediate postoperative period. Peripheral opacification was seen in 102 eyes and central opacification in 1 eye at a 6-month follow-up.

Conclusion:

Indian eyes have a lower rate of axial length growth and keratometry change in comparison with western eyes implying smaller undercorrection in emmetropic IOL power for Indian pediatric eyes to achieve a moderate amount of hyperopia.

Factors associated with early and late failure after goniotomy for primary pediatric glaucoma

Purpose:

To analyze the risk factors associated with early and late failure after goniotomy for primary pediatric glaucoma.

Methods:

A retrospective study was done on infants who underwent goniotomy as the initial surgical procedure for primary pediatric glaucoma, and had a follow-up period ⩾48 months after surgery. Early and late failures were defined as intraocular pressure ⩾18 mmHg or signs of glaucoma progression before and after the end of first year, respectively.

Results:

A total of 81 eyes of 47 children were included. The mean age at the time of surgery was 6.1 ± 6.7 months, 34 children (72.3%) were bilateral. The mean follow-up was 5.9 ± 2.8 years. Of the included eyes, 41 eyes (50.6%) showed success, 25 eyes (30.9%) showed an early failure, and 15 eyes (18.5%) showed a late failure. The mean survival time was 43 months. However, only surgery before the end of the first month and positive consanguinity of the parents (P < 0.01 for both) were independent risk factors for early and late failure of goniotomy for primary pediatric glaucoma. Patients with late failure showed a statistically significant lower preoperative intraocular pressure (P = 0.02). A larger preoperative corneal diameter and a male gender were associated with higher but statistically insignificant failure rates. There were no differences in the early or late failure rates between unilateral and bilateral cases.

Conclusion:

A positive consanguinity of the parents and surgery before the end of the first month are the major predictors of failure of goniotomy.

P.Gly61Glu and P.Arg368His Mutations in CYP1B1 that Cause Congenital Glaucoma may be Relatively Frequent in Certain Regions of Gilan Province, Iran

PURPOSE

To perform a population-based screening of four CYP1B1 mutations-p.Gly61Glu, p.Arg368His, p.Arg390His, and p.Arg469Trp-in the province of Gilan, Iran. Previous studies have shown that CYP1B1 is a cause of disease in approximately 70% of Iranian patients with primary congenital glaucoma (PCG), and that these four mutations constitute the majority of CYP1B1 mutated alleles. The carrier frequencies may even justify premarital screenings.

METHODS

DNA was extracted from the blood samples of 700 individuals recruited in a population-based epidemiology study in Gilan. Screenings were performed using polymerase chain reaction protocols based on restriction fragment length polymorphism or the amplification-refractory mutation system. For confirmation, the DNA of individuals with mutations was sequenced using the Sanger protocol.

RESULTS

Five individuals carried the p.Gly61Glu mutation, and seven carried the p.Arg368His mutation. The p.Arg390His and p.Arg469Trp mutations were not observed in any of the 700 individuals screened. The mutations were not geographically randomly distributed in Gilan; four of the p.Gly61Glu-harboring individuals were from Talesh, and six of the p.Arg368His-harboring individuals were from the eastern regions of Gilan.

CONCLUSION

The frequency of individuals who carry either p.Gly61Glu or p.Arg368His is relatively high in Gilan, and notably high in certain localities within Gilan. We suggest further screenings be performed to definitively assess the need for implementing measures to encourage screening for p.Gly61Glu and p.Arg368His before marriage in Talesh and the eastern regions of Gilan, respectively. Finally, our assessment showed that regional frequencies of CYP1B1 mutations do not necessarily mirror national frequencies.

Primary congenital glaucoma including next-generation sequencing-based approaches: clinical utility gene card

1. NAME OF THE DISEASE (SYNONYMS): Primary congenital glaucoma (PCG). Glaucoma, congenital (GLC). 2. OMIM# OF THE DISEASE: 231300- GLC3A. 600975- GLC3B. 613085- GLC3C. 613086- GLC3D. 617272- GLC3E. 3. NAME OF THE ANALYSED GENES OR DNA/CHROMOSOME SEGMENTS: CYP1B1. LTBP2. MYOC. FOXC1. TEK. 4. OMIM# OF THE GENE(S): CYP1B1 MIM# 601771. LTBP2 MIM# 602091. MYOC MIM# 601652. FOXC1 MIM# 601090. TEK MIM# 600221. Review of the analytical and clinical validity, as well as of the clinical utility of DNA-based testing for variants in the CYP1B1, LTBP2 and MYOC gene(s) in ⊠ diagnostic, ⊠ predictive and ⊠ prenatal settings and for ⊠ risk assessment in relatives.

Refractive error and ocular findings among infants and young children with severe problem behavior and developmental disabilities

The prevalence of refractive error and ocular disorders among infants and young children with severe behavioral problems and developmental disorders is not well defined, particularly in developing countries. We performed a retrospective review of ophthalmic examinations performed during a National Institutes of Health-funded cohort study of very young children in Peru with behavioral problems and at risk for developmental disorders. 222 children between the ages of 0 and 4 years (mean 2.2 ± 0.9 years) were examined and 100 (45.0%) had an abnormal ocular exam. Overall, the prevalence of refractive error was 33.3%, nystagmus was 12.2%, and strabismus was 10.9%. Among children with Down syndrome, refractive error ranged from 46.2% at age 2 to 85.7% at age 4. Refractive error and ocular disorders are highly prevalent even at a young age in children with behavioral problems and developmental disorders. Much of the visual impairment in this population is treatable; early identification and intervention can have a lifelong positive impact on neurodevelopment.

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.

Pediatric Cataract - Importance of Early Detection and Management

Pediatric cataract is often diagnosed and managed late. This delay may be due to the ignorance on the part of the community, financial constraints, delay in the diagnosis and lack of tertiary care facilities. There is an urgent need to include rubella vaccination in the universal immunization program. A Simple Red Reflex test to detect a cataract and guiding the parent for early intervention will go a long way in achieving the target of eliminating cataract as a cause of childhood blindness. The importance of early detection and quick referral to a multispecialty center can save the child of lot many blind-years. These children have the potential to achieve the best possible visual acuity if managed early.

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.

Study protocol: safety and efficacy of propranolol 0.2% eye drops in newborns with a precocious stage of retinopathy of prematurity (DROP-ROP-0.2%): a multicenter, open-label, single arm, phase II trial

BACKGROUND

Retinopathy of prematurity (ROP) still represents one of the leading causes of visual impairment in childhood. Systemic propranolol has proven to be effective in reducing ROP progression in preterm newborns, although safety was not sufficiently guaranteed. On the contrary, topical treatment with propranolol eye micro-drops at a concentration of 0.1% had an optimal safety profile in preterm newborns with ROP, but was not sufficiently effective in reducing the disease progression if administered at an advanced stage (during stage 2). The aim of the present protocol is to evaluate the safety and efficacy of propranolol 0.2% eye micro-drops in preterm newborns at a more precocious stage of ROP (stage 1).

METHODS

A multicenter, open-label, phase II, clinical trial, planned according to the Simon optimal two-stage design, will be performed to analyze the safety and efficacy of propranolol 0.2% eye micro-drops in preterm newborns with stage 1 ROP. Preterm newborns with a gestational age of 23-32 weeks, with a stage 1 ROP will receive propranolol 0.2% eye micro-drops treatment until retinal vascularization has been completed, but for no longer than 90 days. Hemodynamic and respiratory parameters will be continuously monitored. Blood samplings checking metabolic, renal and liver functions, as well as electrocardiogram and echocardiogram, will be periodically performed to investigate treatment safety. Additionally, propranolol plasma levels will be measured at the steady state, on the 10th day of treatment. To assess the efficacy of topical treatment, the ROP progression from stage 1 ROP to stage 2 or 3 with plus will be evaluated by serial ophthalmologic examinations.

DISCUSSION

Propranolol eye micro-drops could represent an ideal strategy in counteracting ROP, because it is definitely safer than oral administration, inexpensive and an easily affordable treatment. Establishing the optimal dosage and treatment schedule is to date a crucial issue.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT02504944, registered on July 19, 2015, updated July 12, 2016. EudraCT Number 2014-005472-29.

Propranolol 0.1% eye micro-drops in newborns with retinopathy of prematurity: a pilot clinical trial

BACKGROUND

Oral propranolol reduces retinopathy of prematurity (ROP) progression, although not safely. This study evaluated safety and efficacy of propranolol eye micro-drops in preterm newborns with ROP.

METHODS

A multicenter open-label trial, planned according to the Simon optimal two-stage design, was performed to analyze safety and efficacy of propranolol micro-drops in newborns with stage 2 ROP. To this end, hemodynamic and respiratory parameters were monitored, and blood samples were collected weekly, for 3 wk. Propranolol plasma levels were also monitored. The progression of the disease was evaluated with serial ophthalmologic examinations.

RESULTS

Twenty-three newborns were enrolled. Since the fourth of the first 19 newborns enrolled in the first stage of the study showed a progression to stage 2 or 3 with plus, the second stage was prematurely discontinued. Even though the objective to complete the second stage was not achieved, the percentage of ROP progression (26%) was similar to that obtained previously with oral propranolol administration. However, no adverse effects were observed and propranolol plasma levels were significantly lower than those measured after oral administration.

CONCLUSION

Propranolol 0.1% eye micro-drops are well tolerated, but not sufficiently effective. Further studies are required to identify the optimal dose and administration schedule.

Global prevalence of childhood cataract: a systematic review

Childhood cataract is an avoidable cause of visual disability worldwide and is a priority for VISION 2020: The Right to Sight. There is a paucity of information about the burden of cataract in children and the aim of this review is to assess the global prevalence of childhood cataract. The methodology for the review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We performed a literature search for studies reporting estimates of prevalence or incidence of cataract among children (aged<18 years) at any global location using the Cochrane Library, Medline and Embase up to January 2015. No restrictions were imposed based on language or year of publication. Study quality was assessed using a critical appraisal tool designed for systematic reviews of prevalence. Twenty prevalence and four incidence studies of childhood cataract from five different geographical regions were included. The overall prevalence of childhood cataract and congenital cataract was in the range from 0.32 to 22.9/10000 children (median=1.03) and 0.63 to 9.74/10000 (median=1.71), respectively. The incidence ranged from 1.8 to 3.6/10000 per year. The prevalence of childhood cataract in low-income economies was found to be 0.42 to 2.05 compared with 0.63 to 13.6/10000 in high-income economies. There was no difference in the prevalence based on laterality or gender. This review highlights substantial gaps in the epidemiological knowledge of childhood cataract worldwide, particularly from low and lower middle-income economies. More studies are needed using standard definitions and case ascertainment methods with large enough sample sizes.

Intraocular pressure and biomechanical corneal properties measure by ocular response analyser in patients with primary congenital glaucoma

PURPOSE

To measure the differences in corneal hysteresis (CH) and corneal resistance factor (CRF) in primary congenital glaucoma (PCG) and in control subjects using ocular response analyser (ORA) and also to compare intraocular pressure (IOP) measurements given by ORA against IOP given by Perkins tonometer, a handheld version of Goldman applanation tonometer (GAT), to determine correlation.

METHODS

One hundred and eighteen eyes of 78 patients with PCG (group I) and 103 eyes of 53 controls (group II) were evaluated using ORA. In all participants, IOP was measured using the Perkins tonometer. The ORA device uses applanation pressure peaks to generate the corneal-compensated IOP (IOPcc), which is reportedly independent of corneal thickness, and the measurement of Goldman-correlated IOP (IOPg), which is influenced by corneal thickness.

RESULTS

The measures in group I were as follows: IOPcc 20.92 ± 5.33; IOPg 18.87 ± 6.67; CH 8.51 ± 2.25; CRF 9.85 ± 3.03; and IOP measured by Goldman 18.32 ± 5.13. The measures in group II were as follows: IOPcc 14.33 ± 2.91; IOPg 14.77 ± 3.00; CH 11.37 ± 1.61; CRF 11.02 ± 1.74; and IOP measured by Goldman 13.74 ± 2.42. The differences of all parameters compared between both groups were statistically significant (p < 0.001 for CH and for all IOP measures and p = 0.001 for CRF). The values of IOPcc, IOPg and IOP measured with Goldman were higher in group I than the values in group II. However, CH and CRF values were lower in group I.

CONCLUSION

A decrease in CH and CRF has been observed in patients with PCG compared to controls. Future research should assess how these parameters are modified in PCG and whether they could provide more information about progression.

Surgical outcomes in children with primary congenital glaucoma: a 20-year experience

PURPOSE

To describe demographic criteria of primary congenital glaucoma (PCG) subjects and to evaluate the surgical outcomes of children who underwent angle surgery over a 20-year period.

METHODS

This is a retrospective study of patients diagnosed with PCG who underwent trabeculotomy, trabeculectomy, or combined trabeculotomy-trabeculectomy (CTT). The surgery was considered to be successful if intraocular pressure (IOP) was 21 mm Hg or less with or without treatment.

RESULTS

A total of 148 eyes (85 patients) were included in the study. The majority of the patients were younger than 6 months of age (78.9%), with a median age of 2 months. Sex distribution was relatively even between girls and boys (45:40) (53%/47%). Bilateral disease was seen in 63 patients (74%). The overall success rate was achieved in 80.4%. The majority of the eyes needed only one surgery (105 [70.9%]), 34 eyes (23.0%) needed 2 surgeries, and 7 eyes (4.7%) had 3 surgeries. There was no statistically significant difference in success rate between types of surgery and number of performed procedures. A progressive decline in success rate over time was evident, as success rate dropped from 96.6% at 5 months to less than 50% after 11 years of follow-up.

CONCLUSIONS

Excellent IOP control can be achieved in a majority of patients with equally effective results from all 3 surgical procedures. The surgical outcome of PCG was more favorable in infants presenting before the age of 6 months. Adjuvant topical antiglaucoma medications can augment the surgical success rate.

Surgical interventions for primary congenital glaucoma

BACKGROUND

Primary congenital glaucoma (PCG) manifests within the first few years of a child's life and is not associated with any other systemic or ocular abnormalities. PCG results in considerable morbidity even in developed countries. Several surgical techniques for treating this condition, and lowering the intraocular pressure (IOP) associated with it, have been described.

OBJECTIVES

To compare the effectiveness and safety of different surgical techniques for PCG.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2014, Issue 6), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to June 2014), EMBASE (January 1980 to June 2014), (January 1982 to June 2014), PubMed (January 1946 to June 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov), the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 23 June 2014.

SELECTION CRITERIA

We included all randomized and quasi-randomized trials in which different types of surgical interventions were compared in children under five years of age with PCG.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures specified by The Cochrane Collaboration.

MAIN RESULTS

We included a total of six trials (four randomized and two quasi-randomized) with 102 eyes in 61 children. Two trials were conducted in the USA and one trial each in Egypt, Israel, Lebanon and Saudi Arabia. All trials included children aged younger than one year when diagnosed with PCG, and followed them for periods ranging from six months to five years.No two trials compared the same pair of surgical interventions, so we did not perform any meta-analysis. One trial compared trabeculotomy versus goniotomy; a second trial compared combined trabeculectomy-trabeculotomy with mitomycin C versus trabeculectomy-trabeculotomy with mitomycin C and deep sclerectomy; a third trial compared combined trabeculotomy-trabeculectomy versus trabeculotomy; a fourth trial compared one goniotomy versus two goniotomies; a fifth trial compared trabeculotomy versus viscocanalostomy; and the sixth trial compared surgical goniotomy versus neodymium-YAG laser goniotomy. For IOP change and surgical success (defined by IOP achieved), none of the trials reported a difference between pairs of surgical techniques. However, due to the limited sample sizes for all trials (average of 10 children per trial), the evidence as to whether a particular surgical technique is effective and which surgical technique is better still remains uncertain. Adverse events, such as choroidal detachment, shallow anterior chamber and hyphema, were reported from four trials. None of the trials reported quality of life or economic data.These trials were neither designed nor reported well overall. Two trials were quasi-randomized trials and judged to have high risk of selection bias; four trials were at unclear or high risk for performance bias and detection bias; and we judged one trial to have high risk of attrition bias due to high proportions of losses to follow-up. Due to poor study design and reporting, the reliability and applicability of evidence remain unclear.

AUTHORS' CONCLUSIONS

No conclusions could be drawn from the trials included in this review due to paucity of data. More research is needed to determine which of the many surgeries performed for PCG are effective.

Preterm-associated visual impairment and estimates of retinopathy of prematurity at regional and global levels for 2010

BACKGROUND

Retinopathy of prematurity (ROP) is a leading cause of potentially avoidable childhood blindness worldwide. We estimated ROP burden at the global and regional levels to inform screening and treatment programs, research, and data priorities.

METHODS

Systematic reviews and meta-analyses were undertaken to estimate the risk of ROP and subsequent visual impairment for surviving preterm babies by level of neonatal care, access to ROP screening, and treatment. A compartmental model was used to estimate ROP cases and numbers of visually impaired survivors.

RESULTS

In 2010, an estimated 184,700 (uncertainty range: 169,600-214,500) preterm babies developed any stage of ROP, 20,000 (15,500-27,200) of whom became blind or severely visually impaired from ROP, and a further 12,300 (8,300-18,400) developed mild/moderate visual impairment. Sixty-five percent of those visually impaired from ROP were born in middle-income regions; 6.2% (4.3-8.9%) of all ROP visually impaired infants were born at >32-wk gestation. Visual impairment from other conditions associated with preterm birth will affect larger numbers of survivors.

CONCLUSION

Improved care, including oxygen delivery and monitoring, for preterm babies in all facility settings would reduce the number of babies affected with ROP. Improved data tracking and coverage of locally adapted screening/treatment programs are urgently required.

Assessment of peripapillary retinal nerve fiber layer thickness using scanning laser polarimetry (GDx VCC) in normal Indian children

Purpose:

To obtain reference values of RNFL thickness in normal Indian children and to study the association of RNFL thickness with central corneal thickness(CCT) and axial length(AL).

Materials and Methods:

200 normal Indian children (mean age 8.6 ± 2.9 yrs) were examined on the GDxVCC. The inferior average (IA), superior average (SA), temporal-superior-nasal-inferior-temporal (TSNIT) average and nerve fiber index (NFI) values were recorded and compared between males and females as well as between the different age groups. The association of TSNIT average with AL and CCT was examined.

Results:

Values for the RNFL parameters were-SA: 64.9 ± 9.7, IA: 63.8 ± 8.8, TSNIT average: 53.5 ± 7.7 and NFI 21.5 ± 10.8. Superior, inferior and TSNIT averages did not differ significantly between males and females (P = 0.25, P = 0.19, P = 0.06 respectively; Mann-Whitney U test). No significant differences were found in TSNIT average across age groups. There was a statistically significant positive correlation between CCT and TSNIT average (r = 0.25, r² = 0.06, P < 0.001). The correlation TSNIT average and AL(r = −0.12; r² = 0.01) was not significant (P = 0.2).

Conclusion:

Reference values for RNFL parameters reported for Indian children are similar those reported in adults. There is a small correlation between central corneal thickness and RNFL as reflected in average TSNIT.

Causes of blindness and visual impairment in Latin America

We review what is known in each country of the Latin American region with regards to blindness and visual impairment and make some comparisons to Hispanic populations in the United States. Prevalence of blindness varied from 1.1% in Argentina to 4.1% in Guatemala in people 50 years of age and older, with the major cause being cataract. Diabetic retinopathy and glaucoma are starting to make serious inroads, although epidemiological data are limited, and age-related macular degeneration is now a concern in some populations. Infectious diseases such as trachoma and onchocerciasis are quickly diminishing. Although progress has been made, retinopathy of prematurity remains the major cause of childhood blindness. If VISION 2020 is to succeed, many more epidemiological studies will be needed to set priorities, although some can be of the Rapid Assessment of Avoidable Blindness design. Developing the infrastructure for screening and treatment of ophthalmic disease in Latin America continues to be a challenge.

Ahmed glaucoma valve in children: A review

Pediatric glaucoma is potentially a blinding disease. Although goniotomy and trabeculotomy are associated with good early success rates, eventually 20% of these procedures fail and many children will require additional surgery to control the IOP in the long-term. In this review, we reported that adequate IOP control can be achieved with the placement of Ahmed glaucoma valve and can last 5 or more years. However, most patients will need one or more glaucoma medications at some point after surgery. In addition, the implants may be associated with pupillary irregularities, lenticular opacification as well as tube-related complications, particularly in the first year of life, as the globe is enlarging with age.

Bilateral primary congenital glaucoma in monozygotic twins

Primary congenital glaucoma is an uncommon pediatric ocular disease contributing to a disproportionately high percentage of childhood blindness worldwide. This case report describes bilateral primary congenital glaucoma in monozygotic twins who first presented to an ophthalmologist in Ethiopia at 6 years of age. Both had severe, protracted disease, with only moderate improvement after surgical intervention.

Causes and temporal trends of childhood blindness in Indonesia: study at schools for the blind in Java

AIMS

To ascertain the causes of blindness and severe visual impairment (BL/SVI) in schools for the blind in Java, to identify preventable and treatable causes and to evaluate temporal trends in the major causes.

METHODS

From a total of 504 students, 479 were examined. Data was collected using a modified World Heath Organization Prevention of Blindness (WHO/PBL) eye examination record for children.

RESULTS

The majority of the students (95%) were blind and 4.6% were severely visually impaired. The major anatomical site of BL/SVI was whole globe in 35.9%, retina in 18.9%, lens in 16.4% and cornea in 16.1%. The major underlying aetiology of BL/SVI was undetermined/unknown in 32.7% (mainly microphthalmia, anterior segment dysgenesis and cataract), hereditary factors 31.9% (mainly retinal dystrophies), and childhood disorders 28.5%. Avoidable causes of BL/SVI accounted for 59.9% of the total students, whereas measles blindness was the underlying condition for 23.1% of the preventable causes; cataract and glaucoma accounted for 15.5% and 8.2% of the treatable causes, respectively. Exploration on trends of SVI/BL among two different age groups <16 years and > or = 16 years suggested that childhood disorders and corneal factors have declined, while hereditary disorders have increased. Optic nerve disorder, although not counted as a major cause of blindness, seems to be on the increase.

CONCLUSIONS

More than half of the BL/SVI causes are potentially avoidable. Cataract and corneal disorders related to measles or vitamin A deficiency were the major treatable and preventable causes. Declining proportions of childhood factors and corneal disorders over a period of 10-20 years could reflect improved vitamin A supplementation and measles vaccination coverage in Indonesia. This finding, and the increased proportion of hereditary disease causes, could suggest improving levels of socioeconomic development and health care services.

The key informant method: a novel means of ascertaining blind children in Bangladesh

BACKGROUND

Most information on the causes of blindness has come from examining children in special education. To obtain a more representative population-based sample of children, a novel method was developed for ascertaining severe visually impaired (SVI) or blind (BL) children by training local volunteers to act as key informants (KIs).

OBJECTIVE

To compare the demography and cause of blindness in children recruited by KIs with other ascertainment methods.

METHOD

Children with SVI/BL were recruited in all 64 districts of Bangladesh. Three sources for case ascertainment were utilised: schools for the blind (SpEdu), community-based rehabilitation (CBR) programmes and KIs. All data were recorded using the standard WHO/PBL Eye Examination Record.

RESULTS

1935 children were recruited. Approximately 800 KIs were trained. The majority of the children were recruited by the KIs (64.3%). Children recruited by KIs were more likely to be female (odds ratio (OR) 1.6, p<0.001), of pre-school age (OR 14.1, p<0.001), from rural areas (OR 5.9, p<0.001), be multiply impaired (OR 3.1, p = 0.005) and be suffering from treatable eye diseases (OR 1.3, p = 0.005) when compared with those in SpEdu. Overall a child with an avoidable causes of SVI/BL had 40% (adjusted CI 1.1 to 1.7, p = 0.015) and 30% (CI 1.0 to 1.7, p = 0.033) higher odds of being ascertained using the KIs compared with SpEdu and CBR methods, respectively.

CONCLUSION

Using this innovative approach has resulted in one of the largest studies of SVI/BL children to date. The findings indicate that KIs can recruit large numbers of children quickly, and that the children they recruit are more likely to be representative of all blind children in the community.

Causes of visual impairment in children: a study of 3,210 cases

PURPOSE

To determine causes of visual impairment in children at the Low Vision Service of the Ophthalmic Clinic at the University of São Paulo and at the Brazilian Association for the Visually Impaired People (Laramara), located in São Paulo, Brazil.

PATIENTS AND METHODS

This study evaluated 3,210 visually impaired children (49% female, 51% male; average age, 5.9 years). Visual impairment was present in 57% (visually impaired group) and 43% presented another associated disability (multiple disability group).

RESULTS

The main causes of visual impairment in the visually impaired group were toxoplasmic macular retinochoroiditis (20.7%), retinal dystrophies (12.2%), retinopathy of prematurity (11.8%), ocular malformation (11.6%), congenital glaucoma (10.8%), optic atrophy (9.7%), and congenital cataracts (7.1%). The main causes of visual impairment in the multiple disability group were optic atrophy (37.7%), cortical visual impairment (19.7%), toxoplasmic macular retinochoroiditis (8.6%), retinopathy of prematurity (7.6%), ocular malformation (6.8%), congenital cataracts (6.1%), and degenerative disorders of the retina and macula (4.8%). The retina was the most frequently affected anatomic site in the visually impaired group (49.2%) and the optic nerve in the multiple disability group (39%).

CONCLUSION

Primary, secondary, and tertiary prevention efforts for childhood blindness and visual rehabilitation must be considered in Latin America.

Causes of severe visual impairment and blindness in Bangladesh: a study of 1935 children

OBJECTIVE

To identify the anatomical site and underlying aetiology of severe visual impairment and blindness (SVI/BL) in children in Bangladesh.

DESIGN

A national case series.

METHODS

Children were recruited from all 64 districts in Bangladesh through multiple sources. Causes were determined and categorised using standard World Health Organization methods.

RESULTS

1935 SVI/BL children were recruited. The median age was 132 months, and boys accounted for 63.1% of the sample. The main site of abnormality was lens (32.5%), mainly unoperated cataract, followed by corneal pathology (26.6%) and disorders of the whole eye (13.1%). Lens-related blindness was the leading cause in boys (37.0%) compared with corneal blindness in girls (29.8%). In 593 children, visual loss was due to childhood factors, over 75% being attributed to vitamin A deficiency. Overall 1338 children (69.2%) had avoidable causes. Only 2% of the country's estimated SVI/BL children have access to education and rehabilitation services.

CONCLUSIONS

This is the first large-scale study of SVI/BL children in Bangladesh over two-thirds of whom had avoidable causes. Strategies for control are discussed.

Gene conversion mutation in crystallin, beta-B2 (CRYBB2) in a Chilean family with autosomal dominant cataract

PURPOSE

To map and identify the mutated gene for autosomal dominant cataract (ADC) in a large Chilean family (ADC53).

DESIGN

Experimental study.

PARTICIPANTS

Large Chilean family with ADCs.

METHODS

Linkage analyses using genome-wide polymorphic DNA markers were performed on a family with variable expression of cataracts to map the mutated gene to a chromosome; 2-point lod scores were calculated. Candidate genes in the region of the maximum lod score were sequenced. We compared haplotypes (alleles at closely linked markers) in families with previously reported mutations of the crystallin, beta-B2 gene (CRYBB2).

MAIN OUTCOME MEASURES

Identification of the causative mutation in the ADC53 family.

RESULTS

The ADC locus mapped to chromosome 22 in the region of a cluster of lens beta crystallin genes (CRYBB3, CRYBB2, CRYBB1, and CRYBA4 and the pseudogene CRYBB2P1). We sequenced CRYBB1 and CRYBB2 and found a previously reported mutation and a variant in exon 6 of CRYBB2 that cosegregate with the disease; these changes in CRYBB2 are in the reference (normal) sequence of an adjacent gene CRYBB2P1, a pseudogene. The haplotypes in the ADC53 Chilean family were different from the 2 previously reported families with the mutation.

CONCLUSIONS

The cataracts in the ADC53 Chilean family are caused by a mutation in the CRYBB2 gene; as the 2 variations in CRYBB2 are identical to the reference sequence of pseudogene CRYBB2P1, which has over 97% homology to CRYBB2, a gene conversion probably has occurred. Based on haplotype analyses, the mutation and variant are likely to be caused by independent gene conversions in our family and the previously reported families.

Pediatric and adolescent population with visual impairment: study of 385 cases

OBJECTIVE

To analyze data on the pediatric population attending the Ophthalmologic Clinic's Low Vision Service at the São Paulo University Medical School.

METHODS

Low vision ophthalmologic assessment, from April 1998 to December 2003, of 385 children and adolescents with mean age of 7 years; 51.7% males and 48.3% females. The main data analyzed were age, diagnosis, anatomic site of the ocular injury, visual acuity, and prescription of optical aids.

RESULTS

45.4% were below 6 years, and 54.6% were between 6 and 16 years. 35.5% experienced moderate visual impairment, 26% had severe visual impairment, 8.6% had profound visual impairment, 10.6% were near blind, and 1.6% were blind. The main causes of visual impairment included congenital glaucoma (30.6%), macular retinochoroiditis due to congenital toxoplasmosis (16.7%), congenital cataract (12.8%), retinal and macular inherited disorders (11.7%), and optic atrophy (9.8%). Among school-age children, 52.9% received a prescription of optical aids. The most widely used optical aids for distance were 2.8 X 26 (34.4%); 4.2 X 12 (30.3%); and 6 X 17 (26.8%) telescopic systems. The most frequently prescribed optical aid for near vision was the 2x magnifying bar (33.3%).

CONCLUSIONS

There is a need for prevention of primary (congenital infections), secondary (congenital glaucoma and retinopathy of prematurity), and tertiary (congenital cataract) visual impairment. The prescription of optical aids for school-age children will help them perform better at school and contribute to their social inclusion.

The ‘ideal’ management of retinopathy of prematurity

AIM

Retinopathy of prematurity continues to be a serious, but largely preventable cause of blindness and its detection and treatment is of increasing importance as survival rates of premature babies increase. This is particularly important in Medium Human Development Countries where the guidelines for detection used in the US or UK may not be appropriate.

METHOD

This report addresses identification of infants at risk for retinopathy of prematurity, detection, and treatment of serious disease, and what to do when treatment fails.

RESULTS AND CONCLUSIONS

Retinopathy of prematurity occurs almost exclusively in small premature babies, but the demographic characteristics of these babies vary depending on where they are born. Detection of serious retinopathy requires carefully timed examinations and the treatment criteria will continue to evolve as new therapies are developed. Timely detection and treatment of serious retinopathy of prematurity minimizes the likelihood of blindness, but it is not always successful.

Characteristics of infants with severe retinopathy of prematurity in countries with low, moderate, and high levels of development: implications for screening programs

OBJECTIVE

Retinopathy of prematurity (ROP) is a potentially avoidable cause of blindness in children. The proportion of blindness as a result of ROP varies greatly among countries depending on their level of development, being influenced by the availability of neonatal care, neonatal outcomes, and whether effective screening and treatment programs are in place. The objective of this study was to compare characteristics of premature infants who developed severe ROP between 1996 and 2002 in highly developed countries with less developed countries.

METHODS

This was an observational study. A questionnaire was completed by ophthalmologists in countries with low, moderate, and high development rankings (3 highly developed countries and from 10 less well-developed countries) who screen for ROP in which they supplied birth weights and gestational ages (GAs) of infants who were treated for threshold ROP or identified with more advanced stages of the disease. Birth weights and GAs of infants with severe ROP were measured.

RESULTS

The mean birth weights of infants from highly developed countries ranged from 737 to 763 g compared with values ranging from 903 to 1527 g in less developed countries. Mean GAs of infants from highly developed countries ranged from 25.3 to 25.6 weeks compared with 26.3 to 33.5 weeks in less developed countries. A total of 13.0% of 1091 infants from poorly developed countries exceeded United Kingdom screening criteria; 3.6% exceeded a criteria of <34 weeks' GA and/or <1750 g birth weight.

CONCLUSIONS

These findings suggest that larger, more mature infants are developing severe ROP in countries with low/moderate levels of development compared with highly developed countries. ROP screening programs need to use criteria that are appropriate for their local population.

Causes of blindness at the "Wiyata Guna" School for the Blind, Indonesia

AIM

To determine the anatomical site and patterns of cause of blindness in one of the biggest schools for the blind in Indonesia with a view to determining potentially preventable and treatable causes.

METHODS

165 students in one school for the blind in Bandung, Indonesia, were examined clinically and data reported using the WHO/PBL childhood blindness assessment form.

RESULTS

Most of the students (96.4%) were blind (BL); 3% were severely visually impaired (SVI). The major causes of SVI/BL in this study were: (1) corneal staphyloma, corneal scar, and phthisis bulbi (mainly attributed to infection) in 29.7%; (2) retinal dystrophies (mainly Leber congenital amaurosis, early onset retinitis pigmentosa) in 20.6%; (3) congenital and familial cataract (13.3%); (4) microphthalmus, anophthalmus (10.9%). The whole globe was the major anatomical site of visual loss (32.7%), followed by the retina (26.0%), cornea (17.6%), lens (13.3%), optic nerve (6.1%), and uvea (4.3%).

CONCLUSIONS

This is a small study in a selected population and the results should be interpreted with caution. This blind school study, adopting the WHO/PBL eye form for data analysing, is the first reported for Indonesia. Hereditary disease and infective causes of blindness are the predominant causes of blindness, accounting for 42.4% and 29.7%, respectively. This pattern of causes is a mixed pattern which lies in an intermediate position between the patterns seen in developing countries and those seen in developed countries. The importance both of preventive public health strategies and of specialist paediatric ophthalmic and optical services in the management of childhood blindness in Indonesia are therefore strongly suggested to cover the problems that exist.

A survey of visual impairment in children attending the Royal Blind School, Edinburgh using the WHO childhood visual impairment database

PURPOSE

To assess the aetiology and changing patterns of childhood blindness in one school for the blind in the UK and to assess the use of the World Health Organisation Prevention of Blindness (WHO/PBL) methodology and reporting form in a developed country.

METHODS

One hundred and seven children in one school for the blind and visually impaired in Edinburgh were examined using the WHO/PBL childhood blindness assessment form.

RESULTS

Of the 107 children examined, 87 (81%) were blind or severely visually impaired (corrected visual acuity of <6/60 (20/200) in the better eye). Perinatal related blindness (40%), hereditary disease (26%) and developmental factors (26%) formed the three largest aetiological categories.

CONCLUSION

The pattern of childhood blindness seen in this study was similar to reports from other developed countries. The WHO/PBL reporting form allows detailed comparisons between countries and over time. Additional fields for more detailed reporting of cerebral visual impairment and associated handicaps would increase the usefulness of the WHO/PBL form for population-based studies and for use in developed countries.

Causes of childhood blindness in Malaysia: results from a national study of blind school students

A national study was conducted in children attending six schools for the blind in Malaysia to identify the anatomical site and underlying causes of blindness (BL) and severe visual impairment (SVI), with a view to determine the potentially preventable and treatable causes so that appropriate control measures can be implemented in the future. The standardized clinical examination of eyes was performed and the findings were recorded on the WHO Prevention of Blindness Programme eye examination record form for children with blindness and low vision. A total of 358 children aged between 7 and 17 years were examined, of whom 332 (92.7%) were blind or severely visually impaired. The results relate to these 332 children. Lens was the major anatomical site (22.3%) of visual loss followed by retina (20.8%), whole globe (17.2%), cornea (15.1%), optic nerve (8.7%) and uvea (5.1%). Glaucoma was responsible for BL/SVI in 7.2% and others in 3.6% of cases. Hereditary diseases were responsible for visual loss in 29.5%, intrauterine factors in 4.5%, perinatal factors in 9% and childhood factors in 7.8% of cases. However, the aetiology was unknown in 49.1% of cases which included congenital anomalies of the globe. Childhood cataract and corneal scarring are major treatable causes of BL/SVI that can benefit from future intervention strategies. Perinatal screening for intrauterine factors and hereditary eye diseases, and appropriate interventional therapy will help in reducing the prevalence of childhood blindness.

Blindness and visual impairment in the Americas and the Caribbean

AIM

To summarise available data on the prevalence and causes of visual impairment and blindness in the Americas and the Caribbean.

METHODS

The published literature was searched in Medline and LILACS using the following key words: blindness, visual impairment, prevalence. Articles were reviewed, and the references of the articles were also searched for relevant articles, which were also reviewed.

RESULTS

Using the mortality in children under the age of 5 as an indicator, the overall prevalence of childhood blindness (in the under age 15 group) for the region was estimated at 0.45/1000, with the majority (67%) living in countries with mortality of children under age 5 above 30/1000 live births. Corneal opacities were more common in countries where the under 5 year mortality are above 30/1000 live births and retinopathy of prematurity (ROP) was an important cause in countries with intermediate death rates. For adults, overall blindness rates were not estimated because of the social, economic, and ethnic diversity in the region. The primary causes of visual loss in adults in the Americas were age related eye diseases, notably cataract and glaucoma in the African-American and Hispanic populations, and age related macular degeneration in the white population. Uncorrected refractive error was a significant cause of decreased vision across ages, ethnic groups, and countries.

CONCLUSION

More data are needed on the magnitude and causes of visual loss for the Caribbean and Latin American countries. Rates of blindness and visual loss from available data within these countries are widely disparate. Prevention and control of avoidable blindness needs to be an ongoing focus in this region.

The epidemiology of pediatric glaucoma: the Toronto experience

BACKGROUND

This study was conceived to provide an insight into the spectrum of glaucoma in the pediatric population. We also set out to compare the success of disease control and the prognosis for vision within the different diagnostic subgroups. This is the largest single population of children with glaucoma that has been so described and compared.

METHODS

The charts of children who were first seen between birth and age 16 years and who attended the Hospital for Sick Children with any form of glaucoma between January 1974 and January 1995 were reviewed and entered into the study.

RESULTS

Data are presented for 306 children. Congenital glaucoma was the most common subtype, accounting for 38%. Patients with congenital glaucoma were young, had surgery, and had more operations than any other group except those with aniridia. Goniotomy offered a cure in 47.8% of the patients. A bimodal distribution reflected their visual performance. Patients with aphakic glaucoma, the next most prevalent group (20%), presented at an older age (4.5 years). Surgical intervention was performed in 50% of these children. Nearly all patients with Sturge-Weber syndrome (80%) had surgery. The following glaucoma groups were associated with a poor visual outcome: aniridia, anterior segment developmental anomalies involving the cornea, uveitis with glaucoma other than steroid induced, retinopathy of prematurity, and persistent hyperplastic primary vitreous. Steroid-induced glaucoma and anterior segment dysgenesis, excluding Peters anomaly, had uniformly good outcomes.

CONCLUSION

The ability to control glaucoma in childhood and visual prognosis is highly variable. Particular diagnostic categories do consistently well and some do poorly.

Childhood blindness

PURPOSE

The objective of this study was to summarize available data regarding pediatric blinding diseases worldwide and to present the most up-to-date information on childhood blindness in the United States.

METHODS

We obtained data from a complete search of the world literature and from direct contact with each of the schools for the blind in the United States.

RESULTS

Five percent of worldwide blindness involves children younger than 15 years of age; in developing countries 50% of the population is in this age group. By World Health Organization criteria, there are 1.5 million children worldwide who are blind: 1.0 million in Asia, 0.3 million in Africa, 0.1 million in Latin America, and 0.1 million in the rest of the world. There are marked differences in the causes of pediatric blindness in different regions, apparently based on socioeconomic factors. In developing countries, 30% to 72% of such blindness is avoidable, 9% to 58% is preventable, and 14% to 31% is treatable. The leading cause is corneal opacification caused by a combination of measles, xerophthalmia, and the use of traditional eye medicine. There is no national registry of the blind in the United States, and most of the schools for the blind do not keep data regarding the cause of blindness in their students. From those schools that do have this information, the top 3 causes are cortical visual impairment, retinopathy of prematurity, and optic nerve hypoplasia. There has been a significant increase in both cortical vision loss and retinopathy of prematurity in the past 10 years.

CONCLUSIONS

There are marked regional differences in the prevalence and causes of pediatric blindness, apparently based on socioeconomic factors that limit prevention and treatment schemes. In the United States the 3 leading causes of pediatric blindness are cortical visual impairment, retinopathy of prematurity, and optic nerve hypoplasia. There is a need for more complete and more uniform data based on the established World Health Organization reporting format.

The contribution of low birth weight to severe vision loss in a geographically defined population

AIMS

To describe the birthweight specific rate of severe vision loss among babies born between 1 January 1984 and 31 December 1987 to mothers resident in a geographically defined area, to classify the causes of vision loss by time of origin, and to describe the associated sensory and motor impairments and disabilities.

METHODS

Cases were identified from a population register of children with early childhood impairment, which uses multiple sources of ascertainment. Further clinical information was retrieved from hospital records and by asking ophthalmologists caring for the children.

RESULTS

166 (1.25/1000 live births) children with severe vision loss diagnosed by the age of 5 years were identified. The rate among babies born weighing less than 1500 g at birth was 26 times higher than the rate for babies between 2500 g and 3499 g. These very low birthweight babies contribute 17.5% of all severely visually impaired children. Almost two thirds of children with severe vision loss have a lesion of prenatal origin. Other sensory or motor deficits are present in 69% of the children. Retinopathy of prematurity accounted for 5.4% of all visually impaired children and seven of the 166 children met the criteria for perinatal asphyxia.

CONCLUSIONS

Although the contribution made by babies with a low birth weight to overall severe vision loss in the community is small, many of these children have additional impairments and probably place considerable demands on health and educational services and families. Reduction in the frequency of vision problems in the preschool population as a whole is unlikely to occur until there are major advances in the understanding of the aetiology and prevention of eye conditions of genetic, prenatal, and developmental origin.