Iris Color Distribution and Its Relation with Refractive Errors, Amblyopia, and Strabismus in Children

Purpose: To characterize the prevalence of refractive error and amblyopia among three- to six-year-old children during the period from 2002 to 2011. Methods: About 31,400 children annually (from 16,592 to 40,816) during the period from 2002 to 2011 were enrolled. The preschool vision screening was performed by the Korean Foundation for the Prevention of Blindness (KFPB) annually during a period that extended from March to September. We reviewed the KFPB annual report about the home vision-screening test as performed during the period from 2002 to 2011. Changes in the prevalence and types of refractive error, strabismus, and amblyopia that manifested throughout this period were analyzed. Results: The prevalence of refractive errors ranged from 1.10% in 2002 to 0.42% in 2011. The prevalence of hyperopia and myopia changed little throughout the 10-year study period. Myopia and hyperopia were equally common among the population examined (χ2-test, p = 0.137). The prevalence of anisometropia decreased over time. The annual prevalence of amblyopia ranged from 0.39% to 0.06%, while the overall prevalence of amblyopia dropped from 0.25% in 2002 to 0.06% in 2011. The prevalence of strabismus was highest in 2006 (0.30%) and had decreased by 0.06% in 2011. The type of strabismus showed no significant difference over time (χ2-test, p = 0.579). Conclusions: The prevalence of amblyopia, refractive error, anisometropia, and strabismus was lower in 2011 than in early 2000. The prevalence of hyperopia and myopia as well as strabismus remained similar throughout the study period.

Esotropia and Exotropia Preferred Practice Pattern®

This study assessed the prevalence of strabismus, nystagmus and their risk factors in children born preterm, stratified by gestational age (GA), retinopathy of prematurity (ROP) and ROP treatment. This is a retrospective cohort study with a prospective follow-up in a large cohort of children born preterm and full-term aged 4-17 years. Multivariable logistic regression analyses assessed associations of strabismus and nystagmus with perinatal parameters. Participants were divided into the following groups: controls born at term (GA ≥37 weeks, group 1), children born preterm without ROP and GA 33-36 weeks (group 2), GA 29-32 weeks (group 3), GA ≤28 weeks (group 4), GA ≤32 weeks with untreated ROP (group 5) and GA ≤32 weeks with treated ROP (group 6). 949 children (11.21±3.92 years, 495 females) were included. Strabismus was observed in 6% of children in group 1, 10% in group 2, 12% in group 3, 23% in group 4, 20% in group 5 and 68% in group 6. Nystagmus was observed in 0.8%, 0.4%, 1.8%, 2.6%, 5.0% and 47% in the respective groups. Strabismus was associated with earlier GA (OR=1.08; p=0.01), astigmatism (OR=2.48; p=0.02) and hypermetropia (OR=2.09; p=0.04). Esotropia was associated with weeks of prematurity (OR=1.11; p=0.02), anisometropia (OR=3.09; p=0.02) and hypermetropia (OR=4.17; p<0.001). Nystagmus was associated with ROP (OR=7.49; p=0.03), anisometropia (OR=5.17; p=0.04) and myopia (OR=11.09; p<0.001). Strabismus in children is linked to preterm birth and refractive error, while nystagmus is more prevalent in children with ROP and children with refractive errors.

Latitude and Uveal Melanoma

PurposeIris colour encompasses a continuum from pale blue to very dark brown and is usually classified via a descriptive three colour scale: blue, green‐hazel or brown. Digital imaging technologies provide an opportunity to quantify iris colour, and are increasingly used for studies of genetic variations in iris colour. We explored the use of digital imaging and colour space information for grading of iris colour in post‐mortem eyes, including eyes with choroidal naevi.MethodsPost‐mortem adult human irises (n = 25) were examined and photographed using a Jenoptik digital camera and ProgResCaptureProv2.8.9 software. Standard lighting (colour temperature) and parameters for imaging were established and used for all specimens. Iris colour was graded (n = 5) (using a nine‐category system; Mackey et al. Clin Exp Ophthalmol, 2011). We also developed a method in Photoshop to express iris colour as Hue in the Hue, Saturation, Brightness (HSB) colour space, for comparison with the category grading.ResultsUsing the nine‐category grading end‐point grades (light blue and dark brown) were consistently graded. Intermediate grades were categorised differently for some observers, usually with adjacent categories. Green irises were not observed in this small series. Digital imaging using standard iris images and an averaging filter, provided colour information (Hue) for each iris. This allowed discrimination of iris colour compared to category grading.ConclusionsAs expected category‐grading was not always consistent between observers. We developed a digital imaging approach using HSB color space to give a H value for each iris. We are exploring the utility of processing functions such as gaussian blur. This approach provides a standard iris colour for post‐mortem tissue and will be used for comparison with fundus colour.

ABSTRACTPurpose: To determine the prevalence, types and early-life risk factors associated with strabismus in a multi-ethnic birth cohort of children aged 4-5 years in the first year of school.Methods: Data were collected prospectively over a 3-year period (2012-2015) from children participating in the vision screening program provided by orthoptists and carried out in schools located in the city of Bradford, UK. Prevalence of strabismus was determined for 17,018 children aged 4 to 5 years. Data linkage was undertaken for 4563 children participating in the Born in Bradford birth cohort study and the vision screening program. 4067 children had complete data and were included in the multivariable regression analyses to determine associated factors.Results: 401/17018 (2.4%) children were found to have either a constant or an intermittent strabismus; 179/401 (45%) had an esotropic deviation, 214 (53%) an exotropic deviation, and 8 (2%) had a vertical deviation. No significant difference in the overall prevalence of strabismus was found between the white British, Pakistani, or children of other ethnic origin (P=0.41). Multivariable analysis showed that children of white British ethnicity have twice the odds of having esotropia (OR 2.4, 95% CI: 1.1, 5.3). The odds of having esotropia were highest in children with a hyperopic mean spherical equivalent (OR 2.0, 95% CI: 1.7, 2.6). There was some evidence of an interaction between ethnicity and mean spherical equivalent in children with esotropia (P=0.058).Conclusions: Prevalence of strabismus is consistent with other population-based studies in this cohort of children aged 4-5 years. Prevalence of esotropia (constant or intermittent) is greater in the white British population, odds of esotropia increased with increasing hyperopic refractive error in both white British and Pakistani children. Exotropia (constant or intermittent) was not found to be associated with refractive error, ethnicity, or other early life factors.

Purpose: The purpose of this study was to determine the distribution of iris colour and its relationship to myopia. Methods: A multi-centered, multi-disciplined, cross-sessional study was conducted From March 2021 to December 2021. 300 individuals ranging in age from 11 to 25 years were selected through non-probability purposive sampling technique. All the patients had a maximum of 6 hours of screen time. Mild, moderate and severe degree of myopia was included. All subjects were examined for refraction, and slit lamp examination was performed to compare slit lamp photos to an iris colour grading scheme. Results: Of the 300 subjects 188 (62.66 %) of the participants were female, with mild 70(23 %), moderate 51(17%), and severe 67 (22.33 %) myopia, while 112 (37.33 %) of the participants were male, with mild 45(15 %), moderate 40(13.33%), and severe 27(9 %) myopia. 90% of the participants in the study had Grade 3, 4 and 5 iris color.Subjects with darker iris colors had more myopic refractive error. Study results indicate patients with Grade 5 iris color had a higher likelihood of becoming myopic (p 0.001). Conclusion: Darker iris color was linked to higher myopia-related refractive errors, even when other known myopia-related risk variables were taken into account. Keywords: Refractive Errors, Myopia, Iris , Risk factor

PurposeTo evaluate the prevalence and risk factors of strabismus in children undergoing surgery for unilateral or bilateral cataract with or without intraocular lens implantation.MethodsMedical records of pediatric patients were evaluated from 2000 to 2011. Children undergoing surgery for unilateral or bilateral cataract with at least 1 year of follow-up were included. Children with ocular trauma, prematurity, or co-existing systemic disorders were excluded. The following data were evaluated: strabismus pre- and post-operation; age at surgery; post-operative aphakia or pseudophakia; and visual acuity.ResultsNinety patients were included, 40% had unilateral and 60% had bilateral cataracts. Follow-up was on average 51 months (range: 12-130 months). Strabismus was found preoperatively in 34.4% children, and in 43.3% children at last follow-up. Strabismus developed in 46.2% of children who were orthotropic preoperatively, whereas 32.3% of children who had strabismus before surgery became orthotropic. Strabismus occurred after unilateral or bilateral cataract surgery in 63.9% and 29.6% children, respectively. At the last follow-up, strabismus was found in 46.7% of aphakic and 58.7% of pseudophakic children (P=0.283). Children who developed strabismus were generally operated at a younger age as compared with those without strabismus (mean of 25.9 vs 52.7 months, P<0.001). Final visual acuity was inversely correlated with prevalence of strabismus.ConclusionStrabismus is a frequent complication after cataract surgery in children. Risk factors include unilateral cases and young age at surgery. No correlation was found between prevalence of strabismus and use of intraocular lens. Strabismus was more common in children with poor final visual acuity.

Clinical relevance Good vision is critical for childhood development and education. Pre-school vision screening is important for early detection and treatment of visual problems, and prevention of life-long vision loss. Background The aim of this study was to determine the prevalence of vision impairment (VI) and refractive error (RE) in rural Nepalese children under five years of age. Methods A cross-sectional study, using multistage random sampling, was conducted in the targeted children between 6 and 59 months old, identified by household visits from rural communities of Nepal. Eye examinations [visual acuity (VA), binocular vision, cycloplegic refractions, and anterior and posterior segments] were performed at community health centres. Refractive errors were recorded as a spherical equivalent (SE) and their prevalence was categorised as myopia (SE ≤ −1.00D) and hyperopia (SE ≥ +2.00D) and emmetropia with astigmatism (SE of astigmatism cases ≥ 1.50DC), and their associations with age, gender and ethnicity were explored. Results Of 2226 participating children, VA of 93.4% was reliably tested and among these, 5.9% had VI (presenting VA less than 6/18 in the better eye). Uncorrected RE accounted for 88% of VI. The overall prevalence of RE was also 5.9% (95% CI: 5.0–7.0), which included the prevalence of myopia, hyperopia and emmetropia with astigmatism of 2.4% (1.8–3.1), 2.7% (2.0–3.3) and 0.8% (0.4–1.2), respectively. The prevalence of overall astigmatism (total cases with ≥ 1.50DC) was 1.6% (1.1–2.1). Infants had significantly higher hyperopia compared to pre-schoolers [OR (95% CI: 4.9 (2.6–9.2)], while toddlers had higher likelihood of developing myopia [1.2 (0.9–1.5)]; however, gender and ethnicity had no significant associations. Conclusions The prevalence of VI was high and uncorrected RE was the main cause of VI in rural Nepalese children under five years of age. Early vision screening should be conducted in pre-school children to correct significant RE and avoid the risk of developing refractive VI and amblyopia

Eye colour and SNPs in Danes

This study aimed to identify deaf people with Deaf with Waardenburg Syndrom Type II. In order to achieve the objectives of the study, the qualitative method was used for the one case study. The sample included (2) deaf students from all deaf schools in Jordan, who are between the ages of (9-10), and (Wechsler Intelligence Scale ,WISC-IV) was applied in the language of Performance Scales and Audiometry. The results of the study showed the presence of symptoms in Deaf people with Wardenberg syndrome type II in terms of: auditory sensory loss. The presence of a side shift to the inner corner of the eyes. Premature graying of hair on the front of the head in white and some on the eyelashes or on the eyebrow. The eyebrows are connected to each other. Dark blue or brown eyes with black and pigment color differences in the iris. The root of the nose is wide and the presence of the rabbit's lip. The results of the study also showed that there is an intense focus during communication in the sign language at the hands of the speaker due to the fact that the color contrast of the eyes led to a dispersion of the focus in the sign language. They also have a sense of the direction of light, which may adversely affect the process of visual communication of sign language. The results of the study also showed that the average hearing impairment was the highest category. The study recommends further studies and research related to the level of intelligence of deaf people with Type II syndrome, as well as studies related to visual perception in Deaf people with type 2 Wardenburg syndrome and the inclusion of this syndrome as an important part of the categories of hearing impairment.

We aimed to determine the prevalence and possible ethnic variations in strabismus and amblyopia among multiethnic school-aged children in rural China. A total of 9,263 children (4,347 Han, 3,352 Yi, 799 Dai and 765 Bai) aged 6 to 14 years were analyzed. Comprehensive eye examinations including monocular distance visual acuity, anterior segment examination, autorefraction, cover testing and ocular motility were conducted. Manifested strabismus was detected in 3.53% of the overall population. The prevalence of strabismus was 3.29% in Han, 4.12% in Yi, 2.25% in Dai, and 3.66% in Bai ethnic groups with marginally inter-ethnic differences (P = 0.046). There was an increasing trend in the prevalence of strabismus with increasing age (P < 0.001). Amblyopia affected 132 children (1.43%) overall, with no statistical differences in gender and age. The prevalence of amblyopia was highest in Dai ethnic group (2.00%) and lowest in ethnic Yi ethnic group (1.04%) with no significant difference being detected (P = 0.062). Refractive error and strabismus were the two major factors associated with amblyopia. No significant ethnic differences in strabismus and amblyopia among Chinese ethnic minorities were observed. Refractive error and strabismus were the major causes for amblyopia in rural Chinese children.

Prevalence and causes of visual impairment among hearing impaired students in Lagos, Nigeria

To determine the prevalence of ocular morbidity and refractive error among the children of the squatter settlements in Kathmandu. A cross-sectional study was carried out at five squatter settlement areas at Kathmandu, including 366 children younger than 16 years. Detailed eye examination included the visual acuity testing, cycloplegic refraction, binocular vision assessment, anterior segment examination, and posterior segment examination. Variations in age, sex, and ethnic distribution of the study population were analyzed through analysis of variance. Pearson χ test with Yate correction was used to analyze different types of ocular morbidity. Pearson correlation coefficient test was performed to correlate refractive error in the right eye and the left eye. Majority of children (28.9%) belonged to the age group 8 to 10 years, and most of them belonged to the Manohara settlement area (40.2%). Male-female ratio was 0.7. Uncorrected and best-corrected visual acuity of better than or equal to 6/9 in at least one eye was found in 87.9% and 99.0% children, respectively. Total ocular morbidity was observed in 33.7%. The common type of ocular morbidity was conjunctivitis (11.2%), refractive error (9.0%), and blepharitis (5.4%). Ocular morbidity was common in infants (57.9%; p = 0.043; odds ratio, 2.8) and 14- to 15-year-old children (52.8%; p = 0.002; odds ratio, 2.5). Ocular infection and refractive error represent the common ocular morbidity in children living in squatter settlements.

To evaluate the normal refractive state in horses in NCSU and ECMR and determine the prevalence of naturally occurring refractive errors and their association with breed, age, coat color, iris color, sex, and geographic location. Horses from NCSU (January 2009-November 2012) and ECMR (January 2013-September 2016) underwent ophthalmic examination and streak retinoscopy. Location, color, breed, sex, and iris color were recorded. Gross and net refractive values for each meridian (horizontal and vertical), spherical refraction, astigmatism for both eyes, and anisometry were recorded, and statistical analyses were performed. There is excellent agreement in refraction between the eyes of the same horse (ICC=0.89). The median net horizontal (H), vertical (V), and spherical refraction for the total population (n=690) were H: +0.25 D (min. -6.50 D, max. +2.34 D), V: +0.25 D (min. -7.13 D, max. +2.75D), and spherical: +0.25 D (min. -6.82 D, max. +2.17 D), all with interquartile ranges of -0.25 to 0.25 D. Emmetropia (>-0.50 D and <+0.50 D; >-0.75 D and <+0.75 D) was present in 769/1380 eyes (55.7%) and 926/1380 eyes (67.1%), respectively. Anisometropia was present in 86/690 horses (12.5%). Sex, iris color, and location were significantly associated with refraction values, whereas age, breed, and coat color were not. Most eyes evaluated are emmetropic, or shifted myopically, with excellent agreement between eyes of the same horse. Sex, iris color, and geographic location appear to impact refraction in horses. None.