Limitations in cataract surgical services for children in Ethiopia: a nationwide survey of pediatric cataract surgeons.

BACKGROUND: Bilateral cataract is a significant cause of blindness in children in Ethiopia. This study aimed to identify the resources available for cataract surgery in children, and to assess current surgical practices, surgical output and factors affecting the outcome of surgery in Ethiopia. METHODS: A Google Forms mobile phone questionnaire was emailed to nine ophthalmologists known to perform cataract surgery in young children (0-5 years). RESULTS: All nine responded. All but one had received either 12- or 3-5-month's training in pediatric ophthalmology with hands-on surgical training. The other surgeon had received informal training from an experienced colleague and visiting ophthalmologists. The surgeons were based in seven health facilities: five in the capital (Addis Ababa) and eight in six public referral hospitals and one private center. Over 12 months (2017-2018) 508 children (592 eyes) aged 0-18 years (most < 15 years) were operated by these surgeons. 84 (17%) had bilateral cataract, and 424 (83%) had unilateral cataract mainly following trauma. A mean of 66 (range 18-145) eyes were operated per surgeon. Seventy-one additional children aged > 5 years were operated by other surgeons. There were substantially fewer surgeons per million population (nine for 115 million population) than recommended by the World Health Organization and they were unevenly distributed across the country. Methylcellulose and rigid intraocular lenses were generally available but less than 50% of facilities had a sharp vitrectomy cutter and cohesive viscoelastic. Mean travel time outside Addis Ababa to a facility offering pediatric cataract surgery was 10 h. CONCLUSION: Despite the high number of cases per surgeon, the output for bilateral cataracts was far lower than required. More well-equipped pediatric ophthalmology teams are urgently required, with deployment to under-served areas.

Outcome of paediatric cataract surgery in Northwest Ethiopia: a retrospective case series.

AIM: To assess visual acuity outcomes, and factors associated with the outcome, of paediatric cataract surgery at the Child Eye Health Tertiary Facility, Gondar, Northwest Ethiopia. METHODS: The medical records of children aged below 16 years who underwent cataract surgery between September 2010 and August 2014 were reviewed for preoperative, surgical and postoperative data. RESULTS: One hundred and seventy-six eyes of 142 children (mean age 7.9 years±4.2 SD, 66% male) who had cataract surgery were included. Twenty-five per cent (35/142) of children had bilateral cataract, 18 (13%) had unilateral non-traumatic cataracts and 89 (63%) had unilateral traumatic cataracts. An intraocular lens was implanted in 93% of eyes. Visual acuities at last follow-up: bilateral cases in the better eye: good (≥6/18 or fix and follow) in 21/34 eyes (62%), borderline (<6/18-6/60) in 4 eyes (12%) and poor (<6/60) in 9 eyes (26%). In unilateral non-traumatic cases: good in 6 eyes (33%), borderline in 3 eyes (17%) and poor in 9 eyes (50%). In unilateral traumatic cases: good in 36 eyes (40%), borderline in 20 eyes (23%) and poor in 33 eyes (37%). In bilateral cataract, worse outcomes were associated with preoperative nystagmus/strabismus. In traumatic cases, worse outcomes were associated with the preoperative trauma-related complications. CONCLUSIONS: Visual acuity improved significantly after surgery, with better outcomes in bilateral cases. Early detection and surgery by a trained surgeon with good follow-up and postoperative rehabilitation can lead to better visual outcomes.

Causes of severe visual impairment and blindness in students in schools for the blind in Northwest Ethiopia.

OBJECTIVES: To determine the causes of severe visual impairment and blindness (SVI/BL) among students in schools for the blind in Northwest Ethiopia and to identify preventable and treatable causes. METHOD: Students attending nine schools for the blind in Northwest Ethiopia were examined and causes assigned using the standard WHO record form for children with blindness and low vision in May and June 2015. RESULTS: 383 students were examined, 357 (93%) of whom were severely visually impaired or blind (<6/60 in their better eye). 253 (70.9%) were aged 16 years or above and 228 (63.9%) were males. 100 students aged <16 years were blind and four were SVI, total 104. The major anatomical site of visual loss among those 0-15 years was cornea/phthisis (47.1%), usually due to measles and vitamin A deficiency, followed by whole globe (22.1%), lens (9.6%) and uvea (8.7%). Among students aged 16 years and above, corneal/phthisis (76.3%) was the major anatomical cause, followed by lens (6.3%), whole globe (4.7%), uvea (3.6%) and optic nerve (3.2%). The leading underlying aetiology among students aged <16 years was childhood factors (39.4%) (13.5% measles, 10.6% vitamin A deficiency), followed by unknown aetiology (54.8%), perinatal (2.9%) and hereditary factors (2.9%). In the older group, childhood factors (72.3%) (25% measles, 15% vitamin A deficiency) were major causes, followed by unknown aetiology (24.1%), perinatal (2.4%) and hereditary factors (0.8%). Over 80% of the causes were avoidable with majority being potentially preventable (65%). CONCLUSION: Corneal blindness, mainly as the result of measles and vitamin A deficiency, is still a public health problem in Northwest Ethiopia, and this has not changed as observed in other low-income countries. More than three-fourth of causes of SVI/BL in students in schools for the blind are potentially avoidable, with measles/vitamin A deficiency and cataract being the leading causes.

Axial length in apparently normal pediatric eyes.

PURPOSE: A key issue in managing children with cataract is to determine whether the eye is of normal axial length for the age of the child. This is important in both prognostication and selection of an appropriate intraocular lens in congenital cataract cases. The aim of this study was to assess the axial lengths recorded for the apparently normal eyes in patients with unilateral congenital cataracts. METHODS: The notes of all patients who had undergone cataract surgery in the last 5 years for unilateral congenital cataract were analyzed and the preoperative data were obtained. Only the contralateral noncataractous eyes with long-term normal visual development and refractive error were included. RESULTS: Twenty eyes were measured in this period. The extrapolated mean axial length at birth was 16.8 mm, with a rapid initial axial growth, with a mean axial length of 20 mm at 12 months of age and 21 mm at age 4 years. CONCLUSIONS: Axial length changes rapidly in the first 18 months of life. The normal data found here at different ages may assist in interpreting perioperative measurements in such children.

The prevalence of nystagmus: the Leicestershire nystagmus survey.

PURPOSE: Nystagmus, which can be infantile (congenital) or acquired, affects all ages. The prevalence of nystagmus in the general population is unknown. New genetic research and therapeutic modalities are emerging. Previous estimates have been based on wider ophthalmic epidemiologic studies within specific occupational or age groups. The authors carried out the first epidemiologic study to specifically establish the prevalence of nystagmus in Leicestershire and Rutland in the United Kingdom. METHODS: Three independent data sources identified persons with nystagmus from the hospital and community. The first was a hospital-based questionnaire and clinical survey (n = 238). The visually impaired services (n = 414) and education services (n = 193) in Leicestershire provided the second and third separately obtained community-based sources of information. Capture-recapture statistical analysis was used to estimate prevalence. RESULTS: The prevalence of nystagmus in the general population was estimated to be 24.0 per 10,000 population (95% confidence interval [CI], +/-5.3). The most common forms of nystagmus were neurologic nystagmus (6.8 per 10,000 population; 95% CI, +/-4.6), nystagmus associated with low vision such as congenital cataracts (4.2 per 10,000; 95% CI, +/-1.2), and nystagmus associated with retinal diseases such as achromatopsia (3.4 per 10,000 population; 95% CI, +/-2.1). Within ethnic groups, nystagmus was significantly more common in the white European population than in the Asian (Indian, Pakistani, other Asian backgrounds) population (P = 0.004). CONCLUSIONS: The findings suggest that nystagmus is more common in the general population than previously thought. This may be of significance in resource allocation and health care planning.

Ophthalmological aspects of Pierson syndrome.

PURPOSE: To study the ocular phenotype of Pierson syndrome and to increase awareness among ophthalmologists of the diagnostic features of this condition. DESIGN: Retrospective, observational case series. METHODS: A multicenter study of 17 patients with molecularly confirmed Pierson syndrome. The eye findings were reviewed and compared to pertinent findings from the literature. RESULTS: The most characteristic ocular anomaly was microcoria. A wide range of additional abnormalities were found, including posterior embryotoxon, megalocornea, iris hypoplasia, cataract, abnormal lens shape, posterior lenticonus, persistent fetal vasculature, retinal detachment, variable axial lengths, and glaucoma. There was high interocular and intrafamilial variability. CONCLUSIONS: Loss-of-function mutations in laminin beta2 (LAMB2) cause a broad range of ocular pathology, emphasizing the importance of laminin beta2 in eye development. Patients with Pierson syndrome can initially present with ocular signs alone. In newborns with marked bilateral microcoria, Pierson syndrome should be considered and renal function investigated.

Phenotypical characteristics of idiopathic infantile nystagmus with and without mutations in FRMD7.

Idiopathic infantile nystagmus (IIN) consists of involuntary oscillations of the eyes. The familial form is most commonly X-linked. We recently found mutations in a novel gene FRMD7 (Xq26.2), which provided an opportunity to investigate a genetically defined and homogeneous group of patients with nystagmus. We compared clinical features and eye movement recordings of 90 subjects with mutation in the gene (FRMD7 group) to 48 subjects without mutations but with clinical IIN (non-FRMD7 group). Fifty-eight female obligate carriers of the mutation were also investigated. The median visual acuity (VA) was 0.2 logMAR (Snellen equivalent 6/9) in both groups and most patients had good stereopsis. The prevalence of strabismus was also similar (FRMD7: 7.8%, non-FRMD7: 10%). The presence of anomalous head posture (AHP) was significantly higher in the non-FRMD7 group (P < 0.0001). The amplitude of nystagmus was more strongly dependent on the direction of gaze in the FRMD7 group being lower at primary position (P < 0.0001), compared to non-FRMD7 group (P = 0.83). Pendular nystagmus waveforms were also more frequent in the FRMD7 group (P = 0.003). Fifty-three percent of the obligate female carriers of an FRMD7 mutation were clinically affected. The VA's in affected females were slightly better compared to affected males (P = 0.014). Subnormal optokinetic responses were found in a subgroup of obligate unaffected carriers, which may be interpreted as a sub-clinical manifestation. FRMD7 is a major cause of X-linked IIN. Most clinical and eye movement characteristics were similar in the FRMD7 group and non-FRMD7 group with most patients having good VA and stereopsis and low incidence of strabismus. Fewer patients in the FRMD7 group had AHPs, their amplitude of nystagmus being lower in primary position. Our findings are helpful in the clinical identification of IIN and genetic counselling of nystagmus patients.

Mutations in FRMD7, a newly identified member of the FERM family, cause X-linked idiopathic congenital nystagmus.

Idiopathic congenital nystagmus is characterized by involuntary, periodic, predominantly horizontal oscillations of both eyes. We identified 22 mutations in FRMD7 in 26 families with X-linked idiopathic congenital nystagmus. Screening of 42 singleton cases of idiopathic congenital nystagmus (28 male, 14 females) yielded three mutations (7%). We found restricted expression of FRMD7 in human embryonic brain and developing neural retina, suggesting a specific role in the control of eye movement and gaze stability.

Bilateral retinal phototoxic injury during cataract surgery in a child.

The intense illumination of the operating microscope has been implicated in photic retinopathy in patients and in animal studies. We report a case of bilateral macular phototoxicity occurring in an eleven-year-old child who underwent bilateral cataract surgery for radiation cataracts. We are unaware of other reports of retinal toxicity occurring during pediatric cataract surgery. We hypothesize that this child may have been predisposed to macular injury because of previous chemotherapy and radiotherapy exposure. Ophthalmic surgeons should be aware that light toxicity from the operating microscope might also occur in the pediatric population.

Mutations in LRP5 or FZD4 underlie the common familial exudative vitreoretinopathy locus on chromosome 11q.

Familial exudative vitreoretinopathy (FEVR) is an inherited blinding disorder of the retinal vascular system. Autosomal dominant FEVR is genetically heterogeneous, but its principal locus, EVR1, is on chromosome 11q13-q23. The gene encoding the Wnt receptor frizzled-4 (FZD4) was recently reported to be the EVR1 gene, but our mutation screen revealed fewer patients harboring mutations than expected. Here, we describe mutations in a second gene at the EVR1 locus, low-density-lipoprotein receptor-related protein 5 (LRP5), a Wnt coreceptor. This finding further underlines the significance of Wnt signaling in the vascularization of the eye and highlights the potential dangers of using multiple families to refine genetic intervals in gene-identification studies.

Identification of a fourth locus (EVR4) for familial exudative vitreoretinopathy (FEVR).

PURPOSE: Familial exudative vitreoretinopathy (FEVR) is a genetically heterogeneous inherited blinding disorder of the retinal vascular system. To date three loci have been mapped: EVR1 on chromosome 11q, EVR2 on chromosome Xp, and EVR3 on chromosome 11p. The gene underlying EVR3 remains unidentified whilst the EVR2 gene, which encodes the Norrie disease protein (NDP), was identified over a decade ago. More recently, FZD4, the gene that encodes the Wnt receptor Frizzled-4, was identified as the mutated gene at the EVR1 locus. The purpose of this study was to screen FZD4 in a large family previously proven to be linked to the EVR1 locus. METHODS: PCR products were generated using genomic DNA from affected family members with primers designed to amplify the coding sequence of FZD4. The PCR products were screened for mutations by direct sequencing. Genotyping was performed in all available family members using fluorescently labeled microsatellite markers from chromosome 11q. RESULTS: Sequencing of the EVR1 gene, FZD4, in this family identified no mutation. To investigate this family further we performed high-resolution genotyping with markers spanning chromosome 11q. Haplotype analysis excluded FZD4 as the mutated gene in this family and identified a candidate region approximately 10 cM centromeric to EVR1. This new FEVR locus is flanked by markers D11S1368 (centromeric) and D11S937 (telomeric) and spans approximately 15 cM. CONCLUSIONS: High-resolution genotyping and haplotype analysis excluded FZD4 as the defective gene in a family previously linked to the EVR1 locus. The results indicate that the gene mutated in this family lies centromeric to the EVR1 gene, FZD4, and is also genetically distinct from the EVR3 locus. This new locus has been designated EVR4 and is the fourth FEVR locus to be described.

Rapid onset childhood cataracts leading to the diagnosis of autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy.

PURPOSE: To report a case of bilateral cataracts in a child that led to diagnosis of autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy. DESIGN: Observational case report. METHODS: A 12-year-old boy was being investigated for weakness, lethargy, short stature, and blurred vision. He developed bilateral, dense cataracts over a 2-week period. He was found to be hypocalcemic and diagnosed with hypoparathyroidism and autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy. RESULTS: Because of hypoparathyroidism, adrenocortical failure, and insulin-dependent diabetes, it was 9 months before the patient's metabolic imbalance was brought under sufficient control to allow cataract surgery. CONCLUSIONS: Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy should be considered with diagnoses of hypocalcemic cataract.

An early-onset autosomal dominant macular dystrophy (MCDR3) resembling North Carolina macular dystrophy maps to chromosome 5.

PURPOSE: To characterize the phenotype of an autosomal dominant macular dystrophy and identify the chromosomal locus. METHODS: Thirteen members of a four-generation, nonconsanguineous British family were examined clinically and also underwent automated perimetry, fundus fluorescein angiography, and fundus autofluorescence imaging. After informed consent was obtained, blood samples were taken for DNA extraction, and genetic linkage analysis was performed. RESULTS: The retinal changes have an early age of onset and are confined to the macular region. The macular abnormalities vary from mild retinal pigment epithelium (RPE) pigmentary change to atrophy. Drusen-like deposits are present to various degrees and are characteristic of the phenotype. Subretinal neovascular membrane (SRNVM) is an established complication. Genetic linkage analysis established linkage to chromosome 5, region p13.1-p15.33 with a maximum LOD score of 3.61 at a recombination fraction of 0.00 for marker D5S630. The locus for this autosomal dominant macular dystrophy lies between flanking markers D5S1981 and D5S2031. CONCLUSIONS: A novel locus has been identified for early-onset autosomal dominant macular dystrophy on chromosome 5.