RESUMEN
PURPOSE: To assess the axial length (AL) measurement failure rate using partial-coherence interferometry (PCI) and swept-source optical coherence tomography (SS-OCT) in dense cataracts. As a secondary outcome, the SS-OCT biometry was compared to immersion ultrasound. METHODS: This is a prospective cross-sectional and comparative study. Seventy eyes from 70 patients with dense cataracts were enrolled in this study. Dense cataract was defined according to the Lens Opacities Classification System III (LOCS III) scores equal to or more than NO4, NC4, C4, and P3. The failure rate of AL measurement was evaluated using PCI and SS-OCT. Anterior chamber depth (ACD), lens thickness (LT), and AL measurements obtained by SS-OCT were compared with IUS. RESULTS: AL measurement failure rate with PCI was 68.57% and 21.43% with SS-OCT (P = 0.007). AL measurement was achieved in 69.23% of NO4, 66.6% of P3, and 15.3% of mixed cataracts using PCI, while SS-OCT was achieved in 100% of NO4, NO5, P3, and P5 and 76.9% of mixed cataracts. Cortical cataracts alone did not influence AL measurement. Biometric data of ACD, LT, and AL were statistically different comparing US and SS-OCT with a good correlation of AL. CONCLUSION: SS-OCT significantly improves the rate of successful AL measurements when compared to PCI in dense cataracts. The LOCS III clinical cut-off for the use of SS-OCT ocular biometry may well be up to P4 and NO5.
Asunto(s)
Catarata , Tomografía de Coherencia Óptica , Cámara Anterior , Longitud Axial del Ojo/diagnóstico por imagen , Biometría , Catarata/diagnóstico , Estudios Transversales , Humanos , Inmersión , Interferometría , Estudios Prospectivos , Reproducibilidad de los ResultadosRESUMEN
OBJETIVO: Comparar la efectividad del cálculo del poder dióptrico de la lente intraocular con IOL Master y el método de biometría por aplanación convencional. MÉTODOS: Se seleccionó una muestra de 100 ojos (pacientes) mediante un muestreo simple aleatorio, en el Servicio de Catarata del Centro de Microcirugía Ocular, con diagnóstico de catarata unilateral o bilateral en la consulta preoperatorio, desde marzo hasta septiembre de 2006. Se clasificaron en dos grupos según el método utilizado para el cálculo de la lente intraocular. Se analizaron las variables: longitud axial media preoperatoria, promedio queratométrico preoperatorio, componente esférico esperado y obtenido, agudeza visual sin corrección y mejor agudeza visual corregida preoperatoria y posoperatoria. El análisis estadístico de los resultados se realizó mediante un análisis de varianza, la prueba t de Student de comparación de medias para datos pareados y chi cuadrado. Se utilizó un nivel de confiabilidad de 95 por ciento. RESULTADOS: Entre los principales resultados se encontró que la diferencia de las longitudes axiales entre los métodos IOL Master y biometría por aplanación A-Scan fue estadísticamente significativa. La agudeza visual sin corrección aumentó cuatro líneas y la mejor agudeza visual corregida seis líneas en el posoperatorio de los pacientes del grupo I. El 90 por ciento de los pacientes del grupo I, o sea, los calculados con IOL Master quedaron en la emetropía en cuanto al componente esférico. CONCLUSIONES: Se evidenció una diferencia significativa e inferior a la encontrada en estudios internacionales entre las longitudes axiales preoperatorias halladas mediante los métodos IOL Master y biometría por aplanación; resultaron superiores las calculadas por IOL Master. Se obtuvo ganancia en las líneas de la Cartilla de Snellen tanto de la agudeza visual sin corrección como la mejor agudeza visual corregida en ambos grupos (superior en el grupo II). Predomina ron los resultados refrac...
OBJECTIVE: to compare the effectiveness of the intraocular lens dioptric power calculation using IOL Master and the conventional applanation biometry. METHODS: A sample of 100 eyes (patients), diagnosed with unilateral or bilateral cataract in the preoperative consultation service, was selected through simple random sampling in the Ocular Microsurgery Center in the period from March to September, 2006. They were divided into two groups based on the method for intraocular lens calculation. The variables were preoperative mean axial length, preoperative keratometric average, expected and obtained spheral component, visual acuity without correction and better corrected visual acuity preoperatively and postoperatively. The statistical analysis of the results was made by variance analysis, Student's t test for paired mean comparisons and Chi square. The confidence level of 95 percent was used. RESULTS: Among the main results, it was found that the axial length differences between IOL Master and A-Scan applanation biometry was statistically significant. Visual acuity without correction increased 4 lines and the best corrected visual acuity increased 6 lines in the postoperative period of the group I patients. Ninety percent of the group I patients, whose visual acuity was calculated with IOL Master, reached emetropia in terms of the spheral component. CONCLUSIONS: A significant difference but lower than that found in the international studies among the preoperative axial lengths calculated through ILO Master and applanation biometry were evinced. The differences were higher in the lenghts calculated by IOL Master. There was improvement in the number of lines of Snellen´s chart both in the visual acuity without correction and the better corrected visual acuity in the two groups; being better in group II. The refractive results tending to emetropy prevailed, taking into consideration the spheral component reached in both groups, which were also higher in group I