Background Knowing the prevalence of myopia at school age is essential to implement preventive measures and appropriate interventions, ensure access to vision care, promote a healthier educational environment and improve academic performance. The purpose of this study was to determine the prevalence of myopia and its associated sociodemographic risk factors, as well as to estimate the coverage of myopia correction among adolescents in center of Portugal. Methods This cross-sectional study evaluated 1115 adolescents from the 5th to the 9th year of school, with an average of 12.9 years (SD = 1.5) ranging from 10.0 to 18.0 years. Optometric evaluations were carried out in a school environment and consisted of the evaluation of distance visual acuity, assessed using a logarithmic visual acuity chart (ETDRS charts 1 and 2) at 4 m, and measured by refractive error with a pediatric autorefractometer (Plusoptix), by non-cycloplegic. Myopia was defined as spherical equivalent (SE ≤ -0.50 diopter (D)) and uncorrected visual acuity (UVA ≤ 95VAR). Adjusted logistic regression analysis was applied to investigate risk factors. Results We found a myopia rate of 21.5% and a high myopia rate of 1.4%. Higher school level and attendance at urban schools were associated with myopia, but no association was found with age or sex. Only 34.6% of myopic adolescents use the best optical correction and 26.4% do not use any type of optical correction. Conclusions Data on the prevalence of refractive problems in Portugal are scarce and heterogeneous. This study, although regional, provides a valuable contribution with a clear and reproducible methodology, following international guidelines and filling gaps in the existing literature. The results show that the rate of myopia in this age group is similar to reports from other European studies. The high rate of adolescents with uncorrected or undercorrected myopia in Portugal is a problem that deserves attention.

OBJECTIVE: Low visual acuity (VA) is an important public health problem due to its high prevalence and because it needs early diagnosis in order to prevent damage in childhood development and apprenticeship. To describe and analyze low visual acuity (VA) prevalence among school children METHODS: Once performed the VA test to 1st and 4th grades primary school children data were analyzed by separating students according to sex, school grade, wearing of glasses, residence area and level of access to the supplementary medical assistance (SMA). RESULTS: The total of 9,640 students was evaluated during the year of 2000 and they presented a prevalence of low VA of 13.1% (CI 12.5-13.8%). There was a statistical significant lower prevalence in males (11.5%) compared to females (14.9%) - (PR=0.77). There was a statistical significant higher prevalence in 1st grade students (14.1%) compared to 4th grade (11.5%) - (PR=1.22). There was also a statistical significant lower prevalence for those who were not wearing glasses (12.1%) compared to those who were using glasses (42.0%) - (PR=0.29). Concerning to residence areas, Cajuru neighborhood had the lower prevalence of low VA (1.8%) and Vila Sabia neighborhood had the higher prevalence (32.4%), and a positive correlation, according to residence area, between the proportion of people with access to the Supplementary Medical Assistance and the proportion of children wearing glasses was found (r=0.64, p

The School Ophthalmology Health Plan was developed in the State of S. Paulo from 1973 to 1976 in State government schools with a view to detecting the visual problems of school children, and providing them with proper care, backed up by educational activities, and go on to survey the existing ophthalmological situation. Through the decentralization of the Health and Education services' organization the work has reached all the administrative areas of the State of S. Paulo, with the participation of a large contingent of school personnel, and health technicians and specialists, as well as government and private entities and the community in general. Taking into account the methodology used in the Plan, this study analyses some aspects related to the range of the program, the administrative and teaching personel involved, and the identification and health care of school children's visual problems.

A regionalized figure scale (RAD) was developed. The objective was to validate the scale, evaluate the correlation between the visual acuity coefficients, verify the association between the tests, and verify the agreement between the measures. This is a triple-blind, experimental, random technology validation study performed on 246 students. Sensitivity was 88.6 RAD1 and 85.7 RAD2 for the right eye (RE), and 78.6 and 92.9 for the left eye (LE), whereas RE specificity was 95.3 RAD1 and 98.1 RAD2, and, 97.7 and 98.6 for the LE, respectively. As for the positive predictive value, RAD1 was 75.6 RE and 81.5 LE, and RAD2 88.2 RE and 89.7 LE. The negative predictive value in RAD1 was 98.0 RE and 97.3 LE, and in RAD2 97.6 RE and 99.1 LE. For the correlation and association in the RE and LE, p=0.0001. Cronbach's Alpha was 0.929. A statistically significant relation was found between the standard criterion and the scale.

This report presents retrospective data concerning 100 amblyopic patients in São Paulo, Brazil, including: the age of detection, means of detection, age in which therapy was started and follow-up of the patients. Even though most of the cases (65%) had been detected before the age of 7 years, 10.8% of them started the therapy only after 8 years of age, when the treatment of amblyopia may not be so successful. Among the patients who started their therapy before the age of 7 years, 44.8% of them returned only irregularly or didn't return at all. The amblyopia was detected, in the majority of cases, by the parents or the ophthalmologist, and rarely by the pediatrician or at school. The authors discuss such observations, and propose some ways ot improve the therapeutic results in amblyopia.

An evaluation of the results of a visual screening carried out by teachers of public elementary school children considers the referral criteria for a specialized examination recommended in the plan for Preventive Ophthalmology in schools in the State of S. Paulo (Brazil). Among the 411 school children examined, there were 48 over-referral cases and 5 under-referrals. In analysing the over-referrals, it became evident that 36 cases (75%) occurred in pupils with visual acuity above the referral limit considered and that periodic reinforcement in orientation of testers is needed to lessen the number of errors in referrals. Analysis of the referral criterion of 0.7 or less leads to the conclusion that, within the limitations of the resources of medical assistance, it is a convenient criterion in preventive ophthalmology.

Vivemos num mundo rodeado de estímulos, como seres humanos racionais, temos de ter a capacidade de seleccionar os estímulos correctos para as actividades que pretendemos fazer, mas à medida que vamos envelhecendo, todos vamos perdendo capacidades, principalmente a nível visual. É a atenção que permite a focalização selectiva num determinado estímulo filtrando, destacando ou inibindo as informações desnecessárias. A focalização dos recursos de atenção pode ser compreendida como uma reacção automática, ou reflexa, atribuída ao aparecimento de um novo objecto. Sendo assim, se percebermos como a atenção visual se comporta ao longo do envelhecimento, poderemos adoptar comportamentos e estimula-los, para melhorar toda a capacidade atencional, e assim proporcionar à população idosa uma melhor qualidade de vida. No presente estudo pretende-se caracterizar as diferenças de atenção visual na população idosa quando se compara com uma população adulta do mesmo sexo. Para tal realiza-se um teste do campo atencional, do campo visual binocular e da acuidade visual, para perceber como a amostra se comporta. De uma maneira geral verificaram-se diferenças ao comparar o grupo dos jovens com o dos idosos, a nível da atenção simples e da atenção dividida periférica, assim como, denotaram-se diferenças ao nível dos tempos de resposta, nas provas de atenção dividida central, atenção dividida periférica, atenção selectiva central e atenção selectiva periférica. Ou seja, à medida que a tarefa se vai complexificando, os idosos são mais lentos que os jovens, o que está de acordo com a revisão bibliográfica realizada.

Le système visuel présente, à la naissance, de nombreuses fonctions, dont le processus de maturation se fait en des temps divers. Dans ce travail nous montrons d'abord comment la psycophysique et l'électrophysiologie visuelles ont contribué à la mensuration et à l'étude du développement de trois fonctions visuelles: acuité visuelle, sensibilité au contraste et vision des couleurs. Dans un deuxième temps, nous pondérons comment la mesure et le développement de ces fonctions peuvent être compromis dans les cas de pathologies qui afectent le système visuel, telles que naissance prématurée et paralisie cérébrale.

Visual acuity is one of the most studied visual functions during the fi rst years of life. Visual acuity reflects the ability to resolve fine details from an observed object. Grating stimuli has been used in infants, pre-verbal and non-verbal patients to evaluate visual acuity. Clinical methods to measure grating acuity currently available along with normal developmental data of this function are presented.

Purpose: Albinism is a rare genetic disorder of melanin production, which can affect only eyes or simultaneously eyes and skin/hair, resulting respectively in ocular (OA) or oculocutaneous albinism (OCA). Through of a case report of a child with OCA we pretend review ophthalmological manifestations of albinism. Case Report: A girl of West African descent was referenced to our appointment for ophthalmological evaluation of oculocutaneous albinism. Visual acuity was 20/310 OD e 20/630 OS by teller cards. In biomicroscopy, iris hypopigmentation and transillumination was visible, allowing to see spiral vessels and other iris details. Fundoscopy showed a denser and complex choroidal circulation due to lack of pigment in retinal pigment epithelium. Foveal hypoplasia was assumed because foveal pit is not apparent and vessels become less respectful of normal arcade and transverse the macula. Results: Melanin plays an important role in the development of the optic system and it’s absence leads to diverse ocular manifestations, such as: iris hypopigmentation and transillumination , reducted pigmentation of retinal pigment epithelium cells, photoreceptor rod cell deficits, foveal hypoplasia, optic nerve hypoplasia and misrouting of optic nerve at the chiasm, with temporal retina fibers inappropriately routed contralaterally instead of ipsilaterally. Photophobia, nystagmus, reduced visual acuity, color impairment and strabismus are other manifestations usually seen in albinism. Conclusion: Ophthalmologists must be familiar with the specific visual manifestations and needs of these patients. It is essential to correct refractive error to optimize visual acuity. Patients should also be advised to wear tinted glasses and sunblock. In more severely affected children they may benefit of low vision consultation and specialized low vision aids like telescopes.