Person: Piedrahita Alonso, María Elena
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First Name
María Elena
Last Name
Piedrahita Alonso
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Óptica y Optometría
Department
Optometría y Visión
Area
Optica
Identifiers
2 results
Search Results
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Item Comparing methods of determining addition in presbyopes(Clinical and Experimental Optometry, 2008) Antona Peñalba, Beatriz; Barra Lázaro, Francisco; Barrio De Santos, Ana Rosa; Gutiérrez Hernández, Ángel Luis; Piedrahita Alonso, María Elena; Martín Pérez, YolandaBackground: The use of plus lenses to compensate for the reduction in the range of accommodation associated with presbyopia, brings the near point of accommodation to a comfortable distance for near visual tasks. Our aim was to compare the tentative near addition determined using the most common procedures with the final addition prescribed in presbyopic patients. Methods: Sixty-nine healthy subjects with a mean age of 51.0 years (range 40 to 60 years) were studied. Tentative near additions were determined using seven different techniques: dynamic retinoscopy, amplitude of accommodation (AA), age-expected addition, binocular fused cross-cylinder with and without myopisation, near duochrome, and balance of negative and positive relative accommodation. The power of the addition was then refined to arrive at the final addition. Results: The mean tentative near additions were higher than the final addition for every procedure except for the fused cross-cylinder without initial myopisation and ageexpected addition methods. These biases were small in clinical terms (less than 0.25 D) with the exception of the AA procedure (0.34 D). The intervals between the 95% limits of agreement differed substantially and were always higher than ±0.50 D. Conclusions: All the techniques used displayed similar behaviour and provided a tentative addition close to the final addition. Due to the wide agreement intervals observed, the likelihood of error is high and supports the idea that any tentative addition has to be adjusted according to the particular needs of each patient. Among the methods examined here, we would recommend the age-expected procedure, as this technique produced results that correlated best with the final addition.Item Rotation of retinal vascular arcades and comparison with disc-fovea angle in the assessment of cycloposition(British Journal of Ophthalmology, 2014) Piedrahita Alonso, María Elena; Valverde Megías, Alicia; Gómez De Liaño Sánchez, María RosarioBackground/aims: To assess the agreement between disc-fovea angle (DFA) and the retinal vascular arcades rotation to measure cycloposition. Device repeatability and reproducibility between observers were also evaluated. Methods: Cycloplegic retinography was taken in 321 eyes of 165 normal patients and repeated in 18 eyes at least 24 h later. Two independent observers used software to determine DFA, vein-related angle (VRA) and artery-related angle (ARA) in every retinography. Mean value of related angle (MRA) (mean value of VRA and ARA) was calculated. Results: Camera repeatability was good (Intra-class Correlation Coefficient, ICC 0.89). In Bland-Altman analysis, mean VRA, ARA and MRA were 4° to 5° different from DFA (p<0.01). There was poor correlation between DFA and other methods (ICC): DFA versus VRA 0.3, versus ARA 0.4, versus MRA 0.5. Reliability between observers was good in all methods. The multivariate analysis showed no interaction between each method and eye side, sex or observer (p>0.05). Conclusions: The rotation of retinal vascular arcades using a first-order approximation technique is no substitute to DFA when assessing torsion in fundus photographs. Of the methods tested, MRA correlated most closely, but DFA remains the gold standard for cycloposition. The rotation of vascular arcades provides a qualitative assessment, particularly in uncertain macular location.