Comparative study of stereopsis with three different tests: TNO®, Stereo Acuity Test Fly® and StereoTAB® in students in higher school

Purpose: Stereopsis is the perception of depth based on retinal disparity. Global stereopsis depends on the process of random dot stimuli and local stereopsis depends on contour perception. The aim of this study was to correlate 3 stereopsis tests: TNO®, StereoTA B®, and Fly Stereo Acuity Test® and to study the sensitivity and correlation between them, using TNO® as the gold standard. Other variables as near convergence point, vergences, symptoms and optical correction were correlated with the 3 tests. Materials and Methods: Forty-nine students from Escola Superior de Tecnologia da Saúde de Lisboa (ESTeSL), aged 18-26 years old were included. Results: The stereopsis mean (standard-deviation-SD) values in each test were: TNO® = 87.04” ±84.09”; FlyTest® = 38.18” ±34.59”; StereoTA B® = 124.89’’ ±137.38’’. About the coefficient of determination: TNO® and StereoTA B® with R2 = 0.6 e TNO® and FlyTest® with R2 =0.2. Pearson correlation coefficient shows a positive correlation between TNO® and StereoTA B® (r = 0.784 with α = 0.01). Phi coefficient shows a strong and positive association between TNO® and StereoTA B® (Φ = 0.848 with α = 0.01). In the ROC Curve, the StereoTA B® has an area under the curve bigger than the FlyTest® with a sensivity of 92.3% for 94.4% of specificity, so it means that the test is sensitive with a good discriminative power. Conclusion: We conclude that the use of Stereopsis tests to study global Stereopsis are an asset for clinical use. This type of test is more sensitive, revealing changes in Stereopsis when it is actually changed, unlike the test Stereopsis, which often indicates normal Stereopsis, camouflaging a Stereopsis change. We noted also that the StereoTA B ® is very sensitive and despite being a digital application, possessed good correlation with the TNO®.

Registration-by-regression of coronary CTA and X-ray angiography

We evaluate the integration of 3D preoperative computed tomography angiography of the coronary arteries with intraoperative 2D X-ray angiographies by a recently proposed novel registration-by-regression method. The method relates image features of 2D projection images to the transformation parameters of the 3D image. We compared different sets of features and studied the influence of preprocessing the training set. For the registration evaluation, a gold standard was developed from eight X-ray angiography sequences from six different patients. The alignment quality was measured using the 3D mean target registration error (mTRE). The registration-by-regression method achieved moderate accuracy (median mTRE of 15 mm) on real images. It does therefore not provide yet a complete solution to the 3D–2D registration problem but it could be used as an initialisation method to eliminate the need for manual initialisation.

Estudo comparativo da estereopsia com três testes diferentes: TNO®, Fly Stereo Acuity Test® e StereoTAB® em estudantes do ensino superior

Estereopsia define-se como a perceção de profundidade baseada na disparidade retiniana. A estereopsia global depende do processamento de estímulos de pontos aleatórios e a estereopsia local depende da perceção de contornos. O objetivo deste estudo é correlacionar três testes de estereopsia: TNO®, StereoTAB® e Fly Stereo Acuity Test® e verificar a sensibilidade e correlação entre eles, tendo o TNO® como gold standard. Incluíram-se 49 estudantes da Escola Superior de Tecnologia da Saúde de Lisboa (ESTeSL) entre os 18 e 26 anos. As variáveis ponto próximo de convergência (ppc), vergências, sintomatologia e correção ótica foram correlacionadas com os três testes. Os valores médios (desvios-padrão) de estereopsia foram: TNO® = 87,04’’ ±84,09’’; FlyTest® = 38,18’’ ±34,59’’; StereoTAB® = 124,89’’ ±137,38’’. Coeficiente de determinação: TNO® e StereoTAB® com R2=0,6 e TNO® e FlyTest® com R2=0,2. O coeficiente de correlação de Pearson mostra uma correlação positiva de entre o TNO® e o StereoTAB® (r=0,784 com α=0,01). O coeficiente de associação de Phi mostrou uma relação positiva forte entre o TNO® e StereoTAB® (Φ=0,848 com α=0,01). Na curva ROC, o StereoTAB® possui uma área sob a curva maior que o FlyTest®, apresentando valor de sensibilidade de 92,3% para uma especificidade de 94,4%, tornando-o num teste sensível e com bom poder discriminativo.