Person: Antona Peñalba, Beatriz
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First Name
Beatriz
Last Name
Antona Peñalba
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Óptica y Optometría
Department
Optometría y Visión
Area
Optica
Identifiers
6 results
Search Results
Now showing 1 - 6 of 6
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 High AC/A Accommodative Esotropia Strabismus Treated with Contact Lenses: A Single Case Design (N=1) Study(Binocular vision & strabismus quarterly, 2007) González Díaz-Obregón, Enrique; Barra Lázaro, Francisco; Sánchez Pérez, Isabel; Antona Peñalba, Beatriz; Barrio De Santos, Ana RosaBACKGROUND AND PURPOSE: The purpose was to determine the efficacy of two types of contact lenses (spherical disposable and aplanatic) as treatment in a patient with esotropia with a high Accommodative Convergence/Accommodation Ratio (AC/A). Due to the possibility of the appearance of accommodative insufficiency in this kind of patient, (i.e., following many years of bifocal glasses use), the elimination of the plus addition lens is advisable. Nevertheless, in some patients, this change leads to the appearance of a residual angle of esodeviation in near vision. It was expected that monofocal aplanatic contact lenses could achieve, due to their optical characteristics, an accurate and orthotropic binocular alignment, without aggravating an undesirable manifestation of the accommodative insufficiency. METHODS: An experimental design of a single case (N=1) was used in which the subject acted as his own control. With bifocal glasses the subject displayed stability in his binocular and accommodative system at every distance of vision for the past three years. We compared the efficacy of two different types of hydrophilic contact lenses to control the angle of deviation, both at distance and at near vision. RESULTS: Neither of the two contact lenses produced the results of stability and the correct binocular alignment that had been achieved with bifocal glasses. This subject experienced a worse manifest esodeviation in distance vision with aplanatic lenses than with the disposable ones. CONCLUSIONS: These monofocal contact lenses did not create acceptable binocular alignment and stability in a subject with a high AC/A accommodative esotropia.Item Intra-examiner repeatability and agreement in accommodative response measurements(Ophthalmic and Physiological Optics, 2009) Antona Peñalba, Beatriz; Sánchez Pérez, Isabel; Barrio De Santos, Ana Rosa; Barra Lázaro, Francisco; González Díaz-Obregón, EnriquePurpose: Clinical measurement of the accommodative response (AR) identifies the focusing plane of a subject with respect to the accommodative target. To establish whether a significant change in AR has occurred, it is important to determine the repeatability of this measurement. This study had two aims: First, to determine the intraexaminer repeatability of AR measurements using four clinical methods: Nott retinoscopy, monocular estimate method (MEM) retinoscopy, binocular crossed cylinder test (BCC) and near autorefractometry. Second, to study the level of agreement between AR measurements obtained with the different methods. Methods: The AR of the right eye at one accommodative demand of 2.50 D (40 cm) was measured on two separate occasions in 61 visually normal subjects of mean age 19.7 years (range 18-32 years). The intraexaminer repeatability of the tests, and agreement between them, were estimated by the Bland-Altman method. We determined mean differences (MD) and the 95% limits of agreement [coefficient of repeatability (COR) and coefficient of agreement (COA)]. Results: Nott retinoscopy and BCC offered the best repeatability, showing the lowest MD and narrowest 95% interval of agreement (Nott: -0.10 +/- 0.66 D, BCC: -0.05 +/- 0.75 D). The 95% limits of agreement for the four techniques were similar (COA = +/- 0.92 to +/- 1.00 D) yet clinically significant, according to the expected values of the AR. The two dynamic retinoscopy techniques (Nott and MEM) had a better agreement (COA = +/- 0.64 D) although this COA must be interpreted in the context of the low MEM repeatability (COR = +/- 0.98 D). Conclusions: The best method of assessing AR was Nott retinoscopy. The BCC technique was also repeatable, and both are recommended as suitable methods for clinical use. Despite better agreement between MEM and Nott, agreement among the remaining methods was poor such that their interchangeable use in clinical practice is not recommended.Item Repeatability intraexaminer and agreement in amplitude of accommodation measurements(Graefe's Archive for Clinical and Experimental Ophthalmology, 2009) Antona Peñalba, Beatriz; Barra Lázaro, Francisco; Barrio De Santos, Ana Rosa; González Díaz-Obregón, Enrique; Sánchez Pérez, IsabelBackground: Clinical measurement of the amplitude of accommodation (AA) provides an indication of maximum accommodative ability. To determine whether there has been a significant change in the AA, it is important to have a good idea of the repeatability of the measurement method used. The aim of the present study was to compare AA measurements made using three different subjective clinical methods: the push-up, push-down, and minus lens techniques. These methods differ in terms of the apparent size of the target, the end point used, or the components of the accommodation response stimulated. Our working hypothesis was that these methods are likely to show different degrees of repeatability such that they should not be used interchangeably. Methods: The AA of the right eye was measured on two separate occasions in 61 visually normal subjects of mean age 19.7 years (range 18 to 32). The repeatability of the tests and agreement between them was estimated by the Bland and Altman method. We determined the mean difference (MD) and the 95% limits of agreement for the repeatability study ( COR) and for the agreement study (COA). Results: The COR for the push-up, push-down, and minus lens techniques were +/- 4.76, +/- 4.00, and +/- 2.52D, respectively. Higher values of AA were obtained using the pushup procedure compared to the push-down and minus lens methods. The push-down method also yielded a larger mean AA than the negative-lens method. MD between the three methods were high in clinical terms, always over 1.75D, and the COA differed substantially by at least +/- 4.50D. The highest agreement interval was observed when we compared AA measurements made using minus lenses and the push-up method (+/- 5.65D). Conclusions: The minus lens method exhibited the best repeatability, least MD (-0.08D) and the smallest COR. Agreement between the three techniques was poor.Item Repeatability and agreement in the measurement of horizontal fusional vergences(Ophthalmic and Physiological Optics, 2008) Antona Peñalba, Beatriz; Barrio De Santos, Ana Rosa; Barra Lázaro, Francisco; González Díaz-Obregón, Enrique; Sánchez Pérez, María IsabelPurpose: This study was designed to determine the repeatability of fusional vergence rangesmeasured using the rotary prisms in the phoropter and in free space using the prism bar. The level of agreement between the two methods was also investigated.. Methods: In two separate sessions, negative and positive fusional vergence ranges (NFV and PFV, respectively) were measured at distance and near in 61 young adults (mean age 19.74, S.D. 2.5 years) who were unfamiliar with the methods used. Base-in and base-out blur, break and recovery points were sequentially determined. Both sets of measurements were obtained by the same examiner. At each distance, NFV was determined first and then PFV. The repeatability of the tests and agreement between measurements made with the phoropter rotary prisms and the prism bar were estimated by the Bland and Altman method. Results: For both the phoropter rotary prisms and prism bar, NFV measurements showed better repeatability than PFV at both near and distance. Mean differences recorded for the NFV break and recovery points were non-significant (under 0.5D), while those observed for PFV were generally greater than 2D. When agreement between the two tests was assessed, it was found that break points were higher when determined using the phoropter rotary prisms, while recovery points were generally higher for the prism bar method. In clinical terms, according to the expected values of the NFV and PFV, agreement between the two techniques can be described as fair, because although mean differences were never greater than 5.5D, 95% agreement intervals were as wide as ±8.00D for NFV and ±13.19D for PFV. Conclusions: The two methods used to measure fusional vergences showed fairly good inter- session repeatability for measuring NFV but repeatability was reduced for PFV measurements. The level of agreement observed between the two methods was such that their interchangeable use in clinical practice is not recommended.Item Validity and repeatability of a new test for aniseikonia(Investigative Ophthalmology & Visual Science, 2007) Antona Peñalba, Beatriz; Barra Lázaro, Francisco; Barrio de Santos, Ana Rosa; González Díaz-Obregón, Enrique; Sánchez Pérez, IsabelPURPOSE. The Aniseikonia Inspector 1.1 (AI) is a new software product to measure aniseikonia using red-green anaglyphs. The purpose of this study was to test whether the AI is a valid and reliable test. METHODS. There were two groups of sample subjects: one at risk of aniseikonia, with anisometropia greater than or equal to 1.00 D (n = 29), and a control group (n = 45). The validity was studied by comparing the measured aniseikonia with the aniseikonia simulated with size lenses. The reliability was estimated by the Bland-Altman statistical method. RESULTS. The results showed that the AI underestimated aniseikonia and that the underestimation was greater in the horizontal than in the vertical direction. The reliability was low, with biases that were clinically insignificant, but the 95% limits of agreement were around +/- 2%. The behavior of the test was similar in both groups of subjects. CONCLUSIONS. The reliability of the AI is only moderate, and professionals are therefore warned to use the results of this test with caution.