Ophthalmological evaluation and integrated intervention in a family with congenital aniridia in Alagoas, Brazil / Avaliação oftalmológica e intervenção integrada em família com aniridia congênita em Alagoas, Brasil

Abstract Objective: We aimed to describe the clinical and phenotypic manifestations as well as the visual prognosis of a family with CA in Northeastern Brazil. Methods: This was a cross-sectional study involving 31 individuals (56 eyes) from the same family presenting CA phenotypes. The study population resided in the municipality of Água Branca, in the backlands of the state of Alagoas, Northeastern Brazil. The clinical and phenotypic variables were analyzed. For the analysis, descriptive statistics (absolute and relative frequency and measures of central tendency and dispersion) and inferential statistics (Shapiro-Wilk and Student's t tests) were used, with 95% confidence intervals and significance set at 5%. Results: Of the 31 individuals, 18 (58.1%) were male, with a mean age of 27.45 ± 17.49 years, with no difference between sexes. Of the 56 eyes evaluated, 26 and 30 were right and left eyes, respectively; 61.3% (n = 19) individuals had complete bilateral aniridia and 25.8% (n = 8) reported a total loss of light perception in both the eyes. The most prevalent ocular abnormalities were nystagmus (n = 27; 87.09%), cataract (n = 20; 64.5%), strabismus (n = 14; 45.2%), corneal changes such as opacities and/or vascularization (n = 13; 41.93%), and ectopia lentis (n = 6; 19.4%). Further, 13 individuals underwent retinal optical coherence tomography, six man and seven women aged 9-48 (mean, 30.15 ± 15.9) years. All patients presented absence of foveal depression as well as reduced macular thickness and visual acuity. Nine subjects underwent phacoemulsification. Conclusion: The study showed wide phenotypic variation among the studied individuals, with poor visual prognosis. The study highlights the need to establish comprehensive care mechanisms for families with the disease.

Resumo Objetivo: Descrever manifestações clínicas e fenotípicas e o prognóstico visual de uma família com aniridia congênita (AC). Métodos: Trata-se de estudo transversal envolvendo 31 indivíduos (56 olhos), de uma mesma família com fenótipo de AC residindo no município de Água Branca, no sertão do estado de Alagoas, região nordeste do Brasil. Foram analisadas variáveis clínicas e fenotípicas. Para a análise, foi utilizada a estatística descritiva (frequência absoluta e relativa e medidas de tendência central e de dispersão) e inferencial (testes de Shapiro-Wilk e t Student). Considerou-se o intervalo de confiança de 95% e a significância de 5%. Resultados: Dos 31 indivíduos, 18 (58,1%) eram do sexo masculino, com média de idade de 27,45±17,49, sem diferença entre os sexos. Dos 56 olhos avaliados, 26 eram olhos direitos e 30 olhos esquerdos: 61,3% (n=19) apresentavam aniridia bilateral total; 25,8% (n=8) referiam perda total de percepção da luz em ambos os olhos. As anormalidades oculares mais prevalentes foram o nistagmo (n=27; 87,09%), catarata (n=20; 64,5%), estrabismo 14 (45,2%), alterações opacidades ou vascularização corneanas (n=13; 41,93%) e ectopia lentis (n=6; 19,4%). Os 13 indivíduos submetidos à tomografia de coerência óptica (OCT) retiniana apresentavam perda da depressão foveal, redução da espessura macular e redução da acuidade visual. Nove indivíduos foram submetidos a cirurgia de facoemulsificação. Conclusão: O estudo mostrou ampla variação fenotípica entre os indivíduos estudados, com pobre prognóstico visual. O estudo destaca a necessidade de estabelecer mecanismos de cuidado integral para as famílias com a doença.

Síndrome WAGR por deleción en heterocigosis del gen WT1: Caso clínico pediátrico / WAGR syndrome by heterozygous deletion of the WT1 gene: Pediatric case report

El síndrome WAGR (tumor de Wilms, aniridia, anomalías genitourinarias y retraso mental) es un trastorno genético infrecuente debido a la deleción de la región 11p13, que contiene los genes WT1 y PAX6. Comprende una combinación distintiva de afecciones clínicas; la aniridia y el tumor de Wilms son las más notables. Se presenta a un lactante de 17 meses con microcefalia, alteraciones oculares (buftalmos, leucocoria, aniridia bilateral), hipoplasia escrotal, testículos en la región inguinal y retraso en el neurodesarrollo, a quien se le realizó el estudio de amplificación de sondas dependiente de ligandos múltiples para WT1, que mostró haploinsuficiencia en las sondas que hibridaban la región 11p13, compatible con una deleción en heterocigosis del gen. Posteriormente, se diagnosticó tumor de Wilms. Dada su baja prevalencia, es importante difundir sus características clínicas y hacer énfasis en un manejo interdisciplinario centrado en la identificación precoz del síndrome y de sus posibles complicaciones. .

WAGR syndrome (Wilms tumor, aniridia, genitourinary anomalies and mental retardation) is an uncommon genetic disorder due to the deletion of the 11p13 region that contains the WT1 and PAX6 genes. It involves a distinctive combination of clinical conditions, with aniridia and Wilms tumor being the most notable. We present a 17-month-old infant with microcephaly, ocular alterations (buphthalmos, leukocoria, bilateral aniridia), scrotal hypoplasia, undescended testes and neurodevelopmental delay who underwent multiplex ligation-dependent probe amplification study for WT1, showing haploinsufficiency in the probes that hybridize to the 11p13 region, compatible with an heterozygous deletion of the gene. Wilms tumor was later diagnosed. WAGR syndrome is infrequent; its report in Latin America is low. It is important to disseminate its clinical characteristics, emphasizing an interdisciplinary management focused on the early identification of both the syndrome and its possible complications.

WAGRO syndrome: a rare genetic condition associated with aniridia and additional ophthalmologic abnormalities / Síndrome WAGRO: uma condição genética rara associada à aniridia e a anormalidades oftalmológicas adicionais

ABSTRACT Aniridia is a congenital eye disorder with a variable degree of hypoplasia or absence of iris tissue. It is caused by loss of function of the PAX6 gene and may be an isolated ocular abnormality or part of a syndrome. WAGRO refers to a rare genetic condition leading to Wilms tumor, aniridia, genitourinary anomalies, mental retardation, and obesity and is caused by a deletion of the short arm of chromosome 11 (11p), where the PAX6 gene is located. Here, we report on an 8-year-old boy with aniridia, polar cataract, and lens subluxation along with neuropsychomotor and speech delays. Karyotype evaluation showed an interstitial deletion including region 11p13-p14, confirming the diagnosis of WAGRO syndrome. In cases of aniridia, a diagnosis of WAGRO syndrome should be considered.

RESUMO A aniridia é uma doença ocular congênita com grau variável de hipoplasia ou ausência do tecido da íris. É causada pela perda de função do gene PAX6 e pode ser uma anormalidade ocular isolada ou parte de uma síndrome. WAGRO refere-se a uma condição genética rara que leva ao tumor de Wilms, aniridia, anomalias geniturinárias, déficit intelectual e obesidade e é causada por uma deleção do braço curto do cromossomo 11 (11p), onde o gene PAX6 está localizado. Aqui, nós relatamos um menino de 8 anos de idade com aniridia, catarata polar e subluxação do cristalino, além de retardo neuropsicomotor e de fala. A avaliação cariotípica revelou uma deleção intersticial envolvendo a região 11p13-p14, confirmando o diagnóstico da síndrome WAGRO. Em casos de aniridia, um diagnóstico de síndrome de WAGRO deve ser considerado.

Hypomelanosis of Ito with Multiple Congenital Anomalies

Hypomelanosis of Ito (HI) is a neurocutaneous disorder, also known as incontinentia pigmenti achromians. HI has been associated with chromosomal abnormalities, especially mosaicism. Herein, we report a case of HI with multiple congenital anomalies. A 2-month-old girl presented with multiple linear and whorling hypopigmentation on the face, trunk, and both extremities and patch alopecia on the scalp. Moreover, she had conical teeth, aniridia of the both eyes, and multiple musculoskeletal problems, including syndactyly and coccyx deviation. Cytogenetic analysis on peripheral blood was normal 46, XX, and no mutation was found in IKBKG gene test.

Identification of a novel PAX6 mutation in a sporadic case with congenital aniridia / 中华医学遗传学杂志

OBJECTIVE@#To identify mutation of the PAX6 gene in a patient with congenital aniridia.@*METHODS@#DNA was extracted from peripheral blood sample of the patient and analyzed by direct PCR-Sanger sequencing.@*RESULTS@#The proband was found to harbor a heterozygous c.239T>A (p.Ile80Asn) mutation of the PAX6 gene. The same mutation was not found in his parents and 150 healthy controls.@*CONCLUSION@#A novel mutation of the PAX6 gene has been identified in a sporadic case with congenital aniridia.

The role of a femtosecond laser in congenital cataract associated with aniridia / O papel do laser de femtosegundo na catarata congênita associada à aniridia

ABSTRACT A patient with bilateral aniridia and progressive congenital cataract was treated at the age of 7 years through phacoaspiration with femtosecond laser capsulotomy, in-the-bag intraocular lens implantation, and pars plana vitrectomy (combined with posterior capsulotomy). The diameter of the planned anterior capsulotomy was 4.7 mm; however, due to elevated tension in the young capsular bag, the capsulotomy diameter increased (to around 6 mm) shortly after release of the tension by the laser. In addition, the patient had a very flat and small cornea, causing the formation of air bubbles in the curved laser interface. This was addressed by filling the gap by using a viscoelastic. A very similar situation was observed in both eyes. Use of the femtosecond laser facilitated a successful outcome in a complex congenital cataract case with a safe capsulotomy that ensured in-the-bag intraocular lens placement.

RESUMO Paciente com aniridia bilateral e catarata congê­nita progressiva foi tratado com a idade de 7 anos através de facoemulsificação com capsulotomia anterior por laser de femtosegundo, implante de lente intra-ocular e vitrectomia via pars plana (combinada com capsulotomia posterior). O diâmetro da capsulotomia anterior prevista foi de 4,7mm, porém, devido à elevada tensão do saco capsular jovem, o diâmetro da capsulotomia aumentou (para cerca de 6mm) logo após a liberação da tensão pelo laser. Além disso, o paciente tinha uma córnea muito plana e pequena, causando a formação de bolhas de ar na interface do laser. Isso foi resolvido preenchendo a lacuna usando um viscoelástico. Uma situação muito semelhante foi observada em ambos os olhos. O uso do laser de femtosegundo facilitou um resultado bem-sucedido em um caso complexo de catarata congênita com uma capsulotomia anterior segura que garantiu a colocação da lente intra-ocular dentro do saco capsular.

A Case of Isolated Traumatic Aniridia in a Pseudophakic Eye

PURPOSE: We report a rare case of isolated traumatic aniridia in a pseudophakic eye. CASE SUMMARY: A 69-year-old female came to our emergency department complaining of right eye pain and visual disturbance after trauma due to fall on the stairs. Five years earlier she had undergone an uncomplicated right sutureless phacoemulsification cataract extraction through a 2.2 mm temporal clear corneal incision, followed by insertion of a folding intracapsular intraocular lens. Total iris expulsion occurred through the cataract incision without extension of the wound or disruption of the posterior capsule or intraocular lens. CONCLUSIONS: We report a rare case of isolated traumatic aniridia in a pseudophakic eye, which has not been reported in the Republic of Korea.

Wilms tumor, aniridia, genitourinary anomalies, and mental retardation syndrome with deletion of chromosome 11p14.3p12

WAGR (Wilms tumor, aniridia, genitourinary anomalies, and mental retardation) syndrome is a rare contiguous gene deletion syndrome caused by deleting genes including WT1 and PAX6 genes in 11p13 region, which is characterized by Wilms tumor, aniridia, genitourinary abnormalities, and intellectual disability. We report the clinical and cytogenetic characteristics of one Korean patient with WAGR syndrome. The patient shows bilateral sporadic aniridia and genital anomalies at 2 months of age. A heterozygous 14.5 Mb interstitial deletion of 11p14.3p12 region was detected by array comparative genomic hybridization. At 2 years and 10 months of age, Wilms tumor is found through regularly abdominal ultrasonography and treated by chemotherapy, radiation therapy and surgery.

Aniridia after blunt trauma and presumed wound dehiscence in a pseudophakic eye / Aniridia após trauma contuso e deiscência presumida da incisão em um olho pseudofácico

ABSTRACT This was a report about a pseudophakic patient who experienced isolated total aniridia without damage to other intraocular structures following blunt trauma to the eye. This patient had a history of uneventful cataract surgery using a small clear corneal incision (CCI). This 71-year-old male presented at our clinic with glare in his left eye. He reported that he had fallen down while drunk and struck his left eye against a stone on the road 15 days earlier. He had undergone cataract surgery on his left eye nine months before the accident at another eye clinic. Slit-lamp examination showed total aniridia in his left eye, but there was no hyphema or cells in the anterior chamber. The intraocular lens in his left eye was stable, without decentration, dislocation, or zonular dehiscence and remained in an intact capsular bag. Review of the medical records from the surgical clinic at which he had undergone cataract surgery indicated no specific findings for any intraocular structure including the iris. He had previously undergone an uneventful phacoemulsification for his left eye through a 2.2 mm CCI, followed by the implantation of a single piece acrylic intraocular lens inside an intact capsular bag. This report showed that small-sized CCIs can be opened postoperatively by trauma and that this can result in isolated total aniridia without damage to other intraocular structures.

RESUMO Relatamos um paciente com história de cirurgia de catarata sem intercorrências usando uma pequena incisão na córnea clara (CCI), que apresentou aniridia total isolada, sem danos a outras estruturas intraoculares, após trauma contuso no olho. Um homem de 71 anos de idade apresentou-se em nossa clínica referindo brilho no olho esquerdo. Ele relatou que, 15 dias antes, havia caído enquanto estava bêbado e atingiu seu olho esquerdo contra uma pedra na estrada. Ele havia passado por uma cirurgia de catarata no olho esquerdo, nove meses antes do acidente em outro serviço. Exame de lâmpada de fenda mostrou aniridia total de olho esquerdo, sem hifema ou células na câmara anterior. A lente intraocular no olho esquerdo ficou estável, com o saco capsular restante intacto, sem descentralização, luxação ou deiscência zonular. O exame dos registros médicos do serviço em que ele havia se submetido a uma cirurgia de catarata não mostraram relatos específicos a qualquer estrutura intraocular, incluindo a íris. O olho esquerdo fora submetido à facoemulsificação sem complicações, através de um CCI de 2,2 mm, seguido pela implantação de uma lente intraocular acrílica peça única dentro do saco capsular intacto. Este relatório mostra que, mesmo pequenas CCIs podem ser abertas no pós-operatório por trauma e que isso pode resultar em aniridia total isolada, sem danos a outras estruturas intraoculares.

Combined transscleral fixation of an artificial iris prosthesis with an intraocular lens / Combinação de fixação transescleral de prótese de íris artificial com lente intraocular

ABSTRACT Post-traumatic aniridia combined with aphakia may be seen after globe injury. Aside from esthetic aspects, partial or total loss of the iris tissue may also be related to various degrees of glare and photophobia. Such patients suffer from severe visual impairment secondary to aphakia. Herein we describe a novel surgical technique for the management of an aphakic eye with traumatic aniridia for a patient who underwent transscleral fixation of a custom-tailored artificial iris prosthesis combined with a rigid intraocular lens (IOL). Tight suturing of the IOL haptic eyelets on the silicone iris prosthesis and fixation of such a complex to the scleral wall may provide excellent cosmetic and functional outcomes in aphakic eyes with aniridia.

RESUMO Aniridia pós-traumática combinada com afacia pode ser observada após lesões do globo ocular. Além do ponto de vista estético, a perda parcial ou total do tecido da íris também pode estar relacionada com vários graus de ofuscamento e fotofobia. Estes pacientes sofrem de deficiência visual grave secundária a afacia. Relata-se uma técnica cirúrgica inovadora para tratamento de um olho com afacia associada à aniridia traumática que foi submetido à fixação transescleral de uma prótese de íris artificial feita sob medida combinada com uma lente intraocular rígida (IOL). A sutura das alças da IOL sobre a prótese iriana de silicone, e a fixação desse complexo na parede escleral podem proporcionar excelente resultado estético e funcional em olhos afácicos com aniridia.

Analysis of PAX6 gene mutation in a family affected with congenital aniridia / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To identify potential mutation of the PAX6 gene in a family affected with congenital aniridia from northeastern China.</p><p><b>METHODS</b>Two patients were collected from the family and underwent full ophthalmologic examinations. Genomic DNA was extracted from all family numbers and 100 healthy controls. The coding regions and flanking sequence of the PAX6 gene were amplified by PCR amplification and subjected to bidirectional DNA sequencing.</p><p><b>RESULTS</b>A nonsense mutation (c.718 C>T) was identified in exon 9 in both patients but not in other unaffected families or the 100 healthy controls. However, obvious difference was noted in the phenotype between the two patients. One of the patient has presented irregular cornea, which was infrequently reported.</p><p><b>CONCLUSION</b>A c.718C>T transitional mutation has been found to underlie the aniridia, which showed an autosomal dominant inheritance pattern in this northeastern Chinese family.</p>

Analysis of PAX6 gene mutations in a Chinese family affected with congenital aniridia / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the mutation of PAX6 gene in a Chinese family affected with congenital aniridia.</p><p><b>METHODS</b>Blood samples were drawn from family members, and DNA was analyzed by direct sequencing.</p><p><b>RESULTS</b>A heterozygous mutation (c.151 G>A) was identified in the PAX6 gene in the proband and other patients from the family. The same mutation was not found among unaffected family members and 160 unrelated healthy controls.</p><p><b>CONCLUSION</b>A novel mutation in the PAX6 gene has been identified in a Chinese family affected with aniridia.</p>

A nonsense PAX6 mutation in a family with congenital aniridia / 소아과

Congenital aniridia is a rare ocular malformation that presents with severe hypoplasia of the iris and various ocular manifestations. Most cases of congenital aniridia are known to be related to mutations in the paired box gene-6 (PAX6), which is an essential gene in eye development. Herein, we report a familial case of autosomal dominant congenital aniridia with four affected members in 3 consecutive generations and describe the detailed ophthalmologic findings for one of these members. As expected, mutational analysis revealed a nonsense mutation (p.Ser122*) in the PAX6 gene. Thus, our findings reiterate the importance of PAX6 mutations in congenital aniridia.

Clinical Features and Molecular Characteristics of Korean Patients with Congenital Aniridia

PURPOSE: To introduce clinical features and molecular characteristics of Korean patients with congenital aniridia. METHODS: Patients with iris hypoplasia were diagnosed clinically as congenital aniridia and were included in the study. Best corrected visual acuity (BCVA) and associated ocular abnormalities (including severity of iris hypoplasia, nystagmus, keratopathy, and foveal hypoplasia), and findings in optical coherence tomography were analyzed. PAX6 analysis,multiplex ligation-dependent probe amplification (MLPA), genomic molecular karyotyping, and candidate gene sequencing were performed to detect genetic abnormalities. RESULTS: 28 patients from 18 families were included in the study. BCVA varied from hand motion to 20/25. No manifest nystagmus was found in 3 patients, but the rest of the patients had pendular horizontal nystagmus. Keratopathy was found in 23 patients, cataracts in 12 patients, and glaucoma in 4 patients. All patients had foveal hypoplasia, including one case with a subtle phenotype. The PAX6 mutation was detected in 13 families out of 18;2 (p.Trp162Leufs*38,p.Gly409Arg) were novel,3 families had the miss ensemutation, and 3 families had alargedeletion in the PAX6 gene. CONCLUSIONS: This study adds 2 novel PAX6 mutations related to congenital aniridia to those previously reported. Congenital aniridia is a serious, sight-threatening ocular malformation, but central vision and the degree of iris hypoplasia were highly variable. The PAX6 mutation was detected in 72% of the patients in this study, and there were no specific clinical features differentiating aniridia with and without PAX6 mutations.

Congenital Aniridia: Long-term Clinical Course, Visual Outcome, and Prognostic Factors

PURPOSE: To describe the clinical course of congenital aniridia and to evaluate prognostic factors for visual outcome after long-term follow-up. METHODS: The medical records of 120 eyes from 60 patients with congenital aniridia were retrospectively reviewed. The prevalence and clinical course of ophthalmic characteristics, systemic disease, refractive errors, and visual acuity were assessed. Prognostic factors for final visual outcomes were analyzed. RESULTS: Aniridic keratopathy developed in 82 (69%) of 119 eyes. Macular hypoplasia was observed in 70 eyes of 35 patients (91%). Cataract was observed in 63 of 120 eyes (53%). Nystagmus was present in 41 patients (68% of 60 patients) at the initial visit but decreased in five patients (8% of 60 patients). Ocular hypertension was detected in 19 eyes (20% of 93 eyes), six (32% of 19 eyes) of which developed secondarily after cataract surgery. The mean changes in spherical equivalent and astigmatism during the follow-up period were -1.10 and 1.53 diopter, respectively. The mean final visual acuity was 1.028 logarithm of minimal angle of resolution. Nystagmus and ocular hypertension were identified as prognostic factors for poor visual outcome. CONCLUSIONS: Identification of nystagmus and ocular hypertension was important to predict final visual outcome. Based on the high rate of secondary ocular hypertension after cataract surgery, careful management is needed.

Esophageal Dysmotility in Gillespie Syndrome

No abstract available.

Identification of a novel PAX6 mutation in a family with congenital aniridia / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To detect potential mutation in a Chinese family where two individuals were affected with hereditary congenital aniridia.</p><p><b>METHODS</b>Peripheral blood samples were taken for genomic DNA extraction. All of the 15 exons of PAX6 gene were amplified with PCR. The product were purified with gel electrophoresis and sequenced.</p><p><b>RESULTS</b>In both patients, a novel deletion mutation (c.957-958delCA) in exon 13 of the PAX6 gene was identified, which has produced a terminator codon. The same mutation was not found in healthy controls.</p><p><b>CONCLUSION</b>A c.957-958delCA mutation of PAX6 gene is probably the cause of aniridia in this Chinese family.</p>

Aniridia congénita / Congenital aniridia

Presentar un caso de aniridia congénita bilateral asociada con catarata e hipoplasia foveal y revisar la literatura existente. Métodos: revisión de la literatura y de la historia clínica de un paciente que consultó al Hospital de San José de Bogotá DC. Conclusiones: la aniridia es una alteración panocular, bilateral, muy poco frecuente que afecta la córnea, cámara anterior, iris, cristalino, retina, mácula y nervio óptico. Tiene una incidencia entre 1:64.000 y 1:100.000. Puede encontrarse de manera aislada o en asociación con otros síndromes, incluyendo el tumor de Wilms, anormalidades genitourinarias y retardo mental (síndrome de WARG).

to present one case of bilateral congenital aniridia associated with cataracts and foveal hypoplasia and conduct a review of available literature. Methods: a review of literature and clinical record of a patient who consulted Hospital de San José, Bogotá DC. Conclusions: aniridia is a rare panophthalmic disorder which involves the cornea, anterior chamber, iris, lens, retina, macula and optic nerve. Its incidence is between 1:64.000 and 1:100.000. It may occur alone or associated with other syndromes, such as Wilms tumor, genitourinary abnormalities and mental retardation (WARG Syndrome).

Clinical Manifestations of Foveal Hypoplasia

PURPOSE: To estimate the baseline demographic/ocular characteristics and associated findings of patients with foveal hypoplasia. METHODS: The medical records of 42 patients (84 eyes) who were clinically diagnosed with foveal hypoplasia were retrospectively reviewed. RESULTS: There were 28 males and 14 females with mode age at diagnosis of 1 (range, 0-60 years) year and a mean follow-up period of 9.7 +/- 5.4 years. At the first office visit, the most common complaints were ocular oscillation and face turn. There were 75 eyes (91.5%) with best corrected visual acuity worse than 0.3 at the first visit, but that number decreased to 55 eyes (67.1%) at the last follow-up (age range, 7-60 years). The absolute spherical equivalent of refractive errors was 2.89 +/- 2.96 diopters (D), and 71 eyes had astigmatism with a mean astigmatism of 2.1 +/- 1.1 D. Forty-two patients had associated diseases: 15 (35.7%) with aniridia, 16 (38.1%) with ocular albinism and 11 (26.2%) with oculocutaneous albinism. In addition, strabismus was found in 24 patients (57.1%). CONCLUSIONS: Diseases associated with foveal hypoplasia include aniridia, ocular albinism and oculocutaneous albinism. Since foveal hypoplasia is often associated with high refractive errors and poor vision, an early prescription of eyeglasses is mandatory for management of refractive amblyopia to ensure the development of the best corrected visual acuity.