Refractive Status in Children with Laser-Treated Retinopathy of Prematurity: Our Experience in Bulgaria.

BACKGROUND: With the establishment of laser photocoagulation as a standard treatment modality for prethreshold retinopathy of prematurity (ROP), a dramatic reduction of cases with ROP blindness and severe visual impairment have been reported. In the same time, high refractive errors, a common complication in ROP cases and especially in ROP treated infants, have become the main cause of visual and often severe visual impairment. AIM: The purpose of our study was to analyse the long-term refractive status in children at 3.5 years after laser-treatment for type 1 prethreshold ROP. PATIENTS AND METHODS: A retrospective, one centre study of refractive status of 18 children with laser-treated type 1 prethreshold ROP was conducted. The refraction after cycloplegia with 1% cyclopentolate was measured at a mean age of 3.56 years (SD ± 0.34). Hyperopia was subdivided into two groups - low hyperopia (SE < +5.0 D) and high hyperopia (SE ≥ +5.0 D). Myopia was classified as myopia (SE ≥ -0.25D) and high myopia (SE ≥ -5.0 D). Astigmatism was divided into low astigmatism (plus CD ≥ +1.0 D) and high astigmatism (plus CD ≥ +2.0 D). RESULTS: Thirty-three eyes of 18 children were recruited in the study. Three eyes were excluded because of unfavourable anatomical results. The mean gestational age at birth was 27.3 weeks (24-31 weeks, SD ± 1.78), and the mean birth weight - 928.9 g (550-1500 g, SD ± 252.8). The mean spherical equivalent for the whole group was -1.82 D and ranged from -9.00 D to +4.50 D (SD ± 3.48). Hyperopia was observed in 12 (36.4%) eyes. Myopic refraction had 21 (63.6%) eyes. Astigmatism was detected in 18 (54.5%) eyes. Anisometropia had 3 (16.7%) children. Six children (33.4%) had strabismus (4 esotropia; 2 exotropia). CONCLUSION: High per cent of treated infants for vision-threatening ROP have visual significant refractive errors and strabismus that can cause serious visual impairment if not treated properly and on time.

Prevalence of amblyopia in Bulgaria.

Introduction: The purpose of this study was to establish the prevalence of amblyopia in children, aged 4 to 10 years, in Bulgaria, who underwent a complete eye examination.Methods: The study was designed as cross-sectional epidemiological study, and the results were calculated in percentages. A complete ophthalmological examination was performed on 1,675 children, aged 4 to 10 years (mean age 7.7 years), during the period 01 Feb 2017-21 April 2017, in five cities, in the western part of Bulgaria. All children were verbal, none of them had a neurologic deficit or mental development delay and a complete examination was successfully performed. The ophthalmological examination consisted of: autorefractometry (using pediatric autorefractor with infrared photoretinoscopy), visual acuity, best-corrected visual acuity (BCVA) and visual acuity with pinhole occluder, cover/uncover and alternate cover test, Worth four-dot test, stereopsis, biomicroscopy and funds examination. Amblyopia was defined as reduction of the BCVA for near and far distances under 40/60 on one or on both eyes in the absence of any pathology of the eye, excluding a pathology leading to stimulus deprivation amblyopia, and in the presence of an amblyogenic factor.Results: Out of 1,675 children, 42 (2.5%) were diagnosed with amblyopia: 7% had strabismic amblyopia (3), 59% had anisometropic amblyopia (25), 31% had isoametropic amblyopia (13), and 3% deprivation amblyopia (1). Unilateral amblyopia was diagnosed in 73% (27) of the cases and bilateral amblyopia in 27% (15). For 45% (754) of the children, it was their first visit to an ophthalmologist.Conclusions: The prevalence of amblyopia among these patients (2.5%) is correlating well with the expected, based on data from other authors, between 1.5% and 3.5%. The fact that nearly half of the children (45%) have not been examined by an ophthalmologist is, however, alarming. The lack of a national screening program in Bulgaria could be the main reason. Other factors include: insufficient number of pediatric ophthalmologists in the country and the lack of awareness among the parents.

Amblyopia screening in Bulgaria.

PURPOSE: To determine the prevalence of amblyopia and the average age at first ophthalmological examination of school-aged children from northwestern Bulgaria. METHODS: Visual acuity testing, stereopsis, orthoptics, ocular motility, non-cycloplegic refraction, direct ophthalmoscopy, and external ocular inspection were performed. Cycloplegic refraction and indirect ophthalmoscopy were done as necessary. A total of 2,054 children (1,020 girls and 1,034 boys) were divided into three age groups: 6 to 8 years (803 children), 8 to 10 years (719 children), and 10 to 12 years (530 children). RESULTS: A total of 1,861 children (90.6%) received their first examination: 754 (93.9%) aged 6 to 8 years, 638 (88.7%) aged 8 to 10 years, and 469 (88.2%) aged 10 to 12 years. Amblyopia was detected in 88 children (4.3%): 42 (5.2%) aged 6 to 8 years, 27 (3.8%) aged 8 to 10 years, and 19 (3.6%) aged 10 to 12 years. The first group had higher prevalence compared to countries with well-developed screening programs. Refractive errors were detected in 403 children (19.7%): 125 (15.6%) aged 6 to 8 years, 146 (20.3%) aged 8 to 10 years, and 132 (24.8%) aged 10 to 12 years. The estimated prevalence increases with age. Strabismus was detected in 24 children (1.2%): 8 (1.0%) aged 6 to 8 years, 7 (1.0%) aged 8 to 10 years, and 9 (1.7%) aged 10 to 12 years. CONCLUSIONS: The lack of screening programs in Bulgaria is the main reason for late diagnosis of amblyopia. The "Do Good "project provided eye examination of school-aged children aged 6 to 12 years, when amblyopia is curable. This model could be used in establishing a Bulgarian national screening program.

LTBP2 and CYP1B1 mutations and associated ocular phenotypes in the Roma/Gypsy founder population.

Primary congenital glaucoma (PCG) is a genetically heterogeneous autosomal recessive disorder, which is an important cause of blindness in childhood. The first known gene, CYP1B1, accounts for a variable proportion of cases in most populations. A second gene, LTBP2, was recently reported in association with a syndrome, in which glaucoma is secondary to lens dislocation. We report on the molecular and clinical profile of 34 families diagnosed as PCG, all originating from the Roma/Gypsy founder population. Comprehensive sequencing analysis revealed a level of heterogeneity unusual for this population, with five CYP1B1 and one ancestral LTBP2 mutation accounting for ∼70% of patients (25 out of 37) and the remainder still unexplained. Homozygosity for the founder LTBP2 p.R299X mutation resulted in a more severe clinical phenotype and poorer outcome despite a markedly higher number of surgical interventions. The genetically homogeneous group of p.R299X homozygotes showed variable phenotypes (presumably also underlying pathogenetic mechanisms), wherein PCG proper with primary dysgenesis of the trabecular meshwork, and Marfan syndrome-like zonular disease with ectopia lentis and later onset secondary glaucoma are two extremes. The spectrum manifestations may occur in different combinations and have a different evolution even within the same sibship or a single patient. Preliminary observations on compounds with mutations in both CYP1B1-LTBP2 suggest that the observed combinations are of no clinical significance and digenic inheritance is unlikely. We provide a population genetics perspective to explain the allelic heterogeneity, comparing the history and geographic distribution of the two major founder mutations--p.R299X/LTBP2 and p.E387K/CYP1B1.