Desarrollo y estandarización de métodos de calibración para equipos utilizados en salud visual (queratómetros, lensómetros y tonómetros), implementados en el hospital universitario de san vicente fundación / Development and standardization of calibration methods for equipment used in visual health (keratometers, lensometers and tonometers), implemented in the hospital universitario de san vicente fundación / Desenvolvimento e estandardização de métodos de calibração para equipamentos utilizados em saúde visual (keratometômetros, lensômetros e tonômetros), implementados no hospital universitario san vicente fundación

Resumen En el campo de la salud visual se utilizan una serie de equipos que ayudan al diagnóstico de la patología del paciente, pero actualmente no existe un método de calibración estandarizado para asegurar las mediciones que se realizan con estos dispositivos. El objetivo era estandarizar métodos de calibración para algunos de los equipos utilizados en el campo de la salud visual como son: queratómetros, lensómetros y tonómetros. Para la calibración de los tres tipos de equipos incluidos en este desarrollo, se utilizaron métodos de comparación directa de la indicación con la magnitud de los patrones utilizados que tenían trazabilidad con laboratorios nacionales e internacionales acreditados bajo la Norma NTC-ISO/IEC 17025:2005. Las mediciones realizadas por cada uno de los técnicos a los diferentes tipos de equipos en condiciones de repetibilidad y utilizando el método adoptado, se hicieron estadísticamente con la herramienta Anova Simple de Statgraphics, arrojando resultados satisfactorios con un valor-P por encima de 0,05, igualmente se realizaron pruebas de exactitud, linealidad y robustez con resultados positivos. Los métodos adoptados fueron exitosamente validados y posteriormente estandarizados bajo la acreditación en la Norma NTC-ISO/IEC 17025:2005.

Abstract In the field of visual health a series of equipment are used to aid in the diagnosis and treatment of the patient's pathology. Urrently there is no standardized calibration method to ensure the measurements performed with these devices. The objective was to standardize calibration methods for some of the equipment used in the field of visual health such as keratometers, lensometers and tonometers. For the calibration of the three types of equipment included in this development, methods of direct comparison were used of the indication with the magnitude of the standards that had traceability with national and international laboratories accredited under the NTC-ISO / IEC 17025: 2005 standard. The measurements made by each of the technicians to the different types of equipment were done under repeatable conditions and using the adopted methods. Results were analyzed statistically with the simple Anova tool of Statgraphics, yielding satisfactory outcomes with a P-value above 0.05. Tests of accuracy, linearity and robustness were also performed with positive results. The adopted methods were successfully validated and later standardized under the accreditation in NTC-ISO / IEC 17025: 2005 standard.

Resumo No campo da saúde visual utilizam-se uma série de equipas que ajudam ao diagnóstico da patologia do paciente, mas, atualmente não existe um método de calibração padronizado para assegurar as medidas que se realizam com estes dispositivos. O objetivo foi estandardizar métodos de calibração para alguns das equipas utilizadas no campo da saúde visual como são: ceratômetro, lenteômetros e tonometros. Para a calibração dos três tipos de equipamentos incluídos neste desenvolvimento, utilizaram-se métodos de comparação direta da indicação com a magnitude dos padrões utilizados que tinham rastreabilidade com laboratórios nacionais e internacionais acreditados baixo a Norma NTC-ISO/IEC 17025:2005. As medidas realizadas por cada um dos técnicos aos diferentes tipos de equipamentos em condições de repetir-se e utilizando o método adoptado, se analisaram estatisticamente com a ferramenta anova simples de statgraphics, produzindo resultados satisfatórios com um valor-P acima de 0,05, igualmente se realizaram provas de exatidão linearidade e robustez com resultados positivos. Os métodos adoptados foram validados de maneira exitosa e posteriormente padronizados baixo a acreditação na Norma NTC-ISO/ IEC 17025:2005.

Progression of Myopia in the Patients with Astigmatism over 3.0 Diopters

PURPOSE: To compare myopia progression in patients with astigmatism over 3.0 dipoters and in patients with astigmatism with less than 1.0 diopter. METHODS: Between March 2001 and March 2006, regular refraction was performed in patients without amblyopia or strabismus. Patients with astigmatism over 3.0 diopter were classified into subject group, and patients with astigmatism less than 1.0 diopter were classified into control group. We performed cycloplegic refraction at the first visit, and manifest refraction at follow-up examination. Minimal follow-up period was 12 months. Data analysis was performed with T-test and ANOVA. RESULTS: There was no difference in myopia progression in patients with astigmatism over 3.0 dipoters and in patients with astigmatism with less than 1.0 diopter. Age, sex, type of astigmatism, spherical equivalent, age to start wearing glasses, and time to watch television and computer didn't show significant influence on myopic progression in subject group and control group. Patients with astigmatism over 3.0 diopters in one eye and astigmatism less than 3.0 diopters in the other eye were evaluated and there was no difference in myopia progression between both eyes. Eyes with non-progressive astigmatism over 3.0 diopters showed similar myopia progression with eyes with progressive astigmatism over 3.0 diopters. CONCLUSIONS: There was no difference in myopia progression between patients with astigmatism over 3.0 dipoters and patients with astigmatism with less than 1.0 diopter.

Surgical Results of Unilateral and Bilateral Lateral Rectus Recessions in Exotropia under 25 Prism Diopter

It is the purpose of this study to compare the postoperative results of surgery for 39 patients with exotropia under 25 prism diopters (PD). Two surgical methods were done; 8 to 9mm unilateral recission of the lateral rectus muscle in 17 patients (unilateral gruop) and 4 to 6mm bilateal recession in 20 patients (bilateral group). The preoperative deviations on the average were 20.8PD in unilateral and 22.6PD in bilateral grou, and postoperatie corrections on the average were 16.5PD in unilateral and 22.8PD in bilateral group. The 41.2% in unilateral droup and 59.1% in bilateral group were under +/-5PD in postoperative deviation. There were 12 cases (70.6%) in unilateral and 20 cases (90.9%) in bilateral group showing the amount of deviation less than 10PD of under or overcorrection. InBilateral group, higher success rate was observed, but there was no statistical difference (p=0.053) between the two groups. The limitation of abduction was observed in the 4 cases of unilateral group but there was no significant cosmetic problem. From our surgical results, the outcome of the bilateral recission for the lateral rectus muscle is better than that ofthe unilateral recession for the correction of exotropia under 25PD although there was no statistical difference.

Surgical Results of Adjustable Strabismus Surgery in Horizontal Rectus Muscles

Adjustable strabismus surgery has been done in adult, young adult, and cooperative children and that decrease the rates of overcorrection or undercorrection occurred at immediate and long-term follow up of strabismus surgery. We reviewed the postoperative alignment, drift, and amount of adjustment in 47 patients between 13 and 67 years. We analyzed results for 35 exotropia and 12 esotropia surgeries. All patients underwent a minimum of 8 weeks follow up. The procedure was done by same operator, adjustment was taken at the day afternoon or next day morning. The evaluation of success based on distanct deviation was orthophoric and less than 10 prism diopters. The success rates were 85.71% in exotropia and 91.67% in esotropia. The mean postoperative drift in prism diopters from the alignment immediately after adjustment, or after the surgery if no adjustment was needed, for each group as measured during the most recent follow up was 4.26 for exotropia and 7.5 for esotropia.

The Factors Affecting Consecutive Exotropia with Angle of 20 Prism Diopters or More following Surgery for Esotropia

The purpose of this study is to evaluate the factors that may have a role in the development of postoperative exotropia with the angle of 20 prism diopters (PD) or more. The study group was subdivided into three groups depending on the amount of deviation for consecutive exotropia; group A is the angle of 20PD or more, group B is between 10PD and 18PD, and group C is orthophoria. Comparing group A with C, the presence of amblyopia(p<0.05), postoperative limitation on adduction(p<0.01), postoperative binocular vision(p<0.05) and postoperative A or V pattern(p<0.05) were statistically significant. Among the factors of group A and B, the presence of postoperative limitation on adduction(p<0.05) and refractive error of 3D or more(p<0.05) were signifi cant. We suggest that these factors may have a role to develop large consecutive exotropia, therefore close observation is necessary when these factors are found.