Potential acuity meter accuracy in cataract patients

Gus, Patrı́cia Ioschpe; Kwitko, Idel; Roehe, Daniela; Kwitko, Sérgio

doi:10.1016/s0886-3350(00)00409-0

Cited by 22 publications

(24 citation statements)

References 8 publications

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“…Many authors have used case-series data to evaluate the Guyton-Minkowski PAM for predicting postoperative visual acuity after cataract surgery 1,[5][6][7] or to compare this device to other instruments for predicting postoperative visual acuity after cataract surgery. [11][12][13][14][15][16] Two studies have specifically compared the PAM to the Lotmar Visometer.…”

Section: Discussionmentioning

confidence: 99%

“…2 Lotmar documented Moiré fringe testing in 1972 leading to the development of the Visometer, a tool which is able to measure retinal acuity using white light, interferometry in the presence of lenticular, corneal, or vitreous opacities. 3,4 Although validation studies have been performed for the PAM, [5][6][7] no large-scale study has evaluated these two commonly used instruments in a patient population undergoing cataract surgery. The purpose of this study is to analyse the capabilities of both PAM and Visometer in predicting postoperative best-corrected visual acuity (BCVA) and interpret their clinical usefulness in a consecutive series of patients with no known underlying ocular pathology undergoing cataract surgery.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of the potential acuity meter and the visometer in cataract patients

Reid

Maberley

Hollands

2005

Eye

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Purpose To compare the Guyton-Minkowski Potential Acuity Meter (PAM) and the HaagStreit Lotmar Visometer (Visometer) in their ability to predict postoperative best corrected visual acuity (BCVA) in cataract surgery. Setting University of British Columbia/ Vancouver General Hospital Eye Care Center, Vancouver, British Columbia, Canada. Methods In total, 292 eyes (223 patients) of subjects with cataracts and no known macular or optic nerve pathology were recruited over 6 months. Preoperative predictions of postoperative BCVA were compared with actual postoperative BCVA. The usefulness of these instruments as a 'diagnostic test' for predicting true surgical success (defined as postoperative BCVA of 20/40 or better) from predicted surgical success (PAM or Visometer predicted acuity 20/40 or better) was analysed. Results Neither the PAM nor the Visometer predictions were statistically significant predictors of postoperative BCVA. The sensitivities of PAM and Visometer for predicting surgical success were 84.7% and 96.1%, respectively. The specificity of the PAM and Visometer for predicting surgical success was 27.3% and 9.1%, respectively. Overall, 92.7% of patients had 'successful surgery'. Given a predicted success from the PAM or Visometer the post-test probability of success was 93.5% and 93.1%, respectively. Given a predicted failure from the PAM or Visometer there was a post-test probability of surgical success of 87.5% and 84.6%, respectively. Conclusion We found no clinical benefit to support using the PAM or Visometer in the preoperative assessment of cataract patients with no known retinal or optic nerve pathology.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comparison of the potential acuity meter and the visometer in cataract patients

Reid

Maberley

Hollands

2005

Eye

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“…Our method also provides additional information if a super-pinhole potential acuity meter (PAM) 9,10 or laser interferometry is not available or the results are in doubt. 10 Beam deflection gives a qualitative idea of how much refractive irregularity is present but cannot predict how much visual acuity will improve if the cataract is removed.…”

Section: Discussionmentioning

confidence: 99%

Beam-deflection method of diagnosing impaired vision

Frohn

Fink

Dick³

et al. 2001

Journal of Cataract and Refractive Surgery

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We describe a simple method to assign a diagnosis of cataract to patients with obscurely impaired vision as well as to those with mild lens opacities. When the narrowest slit is used in a slitlamp examination, a small beam of light appears on the macula. Routine fundoscopy with the 78.0 diopter lens or a 3-mirror glass is appropriate. If a cataract is present, the beam of light is scattered into several straight lines, distorted lines, or both. This has proved a useful diagnostic tool when the lens appears clear but the patient's vision is impaired, and extensive examinations such as computer tomography or nuclear magnetic resonance tomography for impaired vision may be avoided. The beam-deflection method uses devices that are generally available and can detect cataract in the early stages of development. J Cataract Refract Surg 2001; 27:994 -999 © 2001 ASCRS and ESCRS I n cases of mild cataract with faint lens opacities, it may be difficult to find the cause of obscurely impaired vision. The ophthalmologist may fail to recognize zones of increased light scattering in the nuclear region of the crystalline lens when brunescence is not present. Thus, unremarkable morphology of the eye compartments calls for intensive evaluation including perimetry, electrophysiology, and neuroradiology. These examinations may be avoided by using a simple method we developed to clarify the diagnosis of impaired vision caused by cataract. This beam-deflection approach complements the classic methods of investigation, which typically consist of slitlamp examination with lateral light, Scheimpflug imaging, 1 and laser scattering. 2During fundus examinations with the 3-mirror glass, we observed that the slitlamp's beam was deformed by lens opacities. This phenomenon was only visible at the appropriate slitlamp setting; that is, coaxial light, slightly defocused. This article describes our technique to evaluate vision impaired by cataract, its clinical application, and the optical explanation of the beamdeflection phenomenon. Technique ExaminationThe slitlamp's illumination beam is aligned coaxially with the microscope's viewing axis. The height of the slit is limited by the pupillary aperture, and its width is set as narrow as possible. For the adjustment, the slit is totally closed at first and then slightly reopened.The slit is focused on the macula to arrange the slitlamp, the patient, and the mirror glass in proper position. A 3-mirror glass or a 78 diopter magnifying lens is used. To produce the beam-deflection phenomenon,

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“…Sendo assim, quanto mais informações obtivermos ao exame pré-operatório, principalmente, o potencial de visão do paciente, maior será a chance de proporcionarmos uma real expectativa ao mesmo (1) . Além disso, a presença de comorbidades geralmente associadas pela idade avançada nos casos de catarata de etiologia senil torna ainda mais importante esta avaliação (2) . O "potential acuity meter" (PAM) consiste na projeção de um feixe de luz com optotipos da tabela de Snellen na região macular, preferencialmente através de uma midríase, simulando o potencial de acuidade visual no período pós-operatório após a remoção sem intercorrências da catarata em um paciente sem outras afecções oculares (2)(3)(4) .…”

Section: Resumo Introduçãounclassified

“…Além disso, a presença de comorbidades geralmente associadas pela idade avançada nos casos de catarata de etiologia senil torna ainda mais importante esta avaliação (2) . O "potential acuity meter" (PAM) consiste na projeção de um feixe de luz com optotipos da tabela de Snellen na região macular, preferencialmente através de uma midríase, simulando o potencial de acuidade visual no período pós-operatório após a remoção sem intercorrências da catarata em um paciente sem outras afecções oculares (2)(3)(4) . Este trabalho avalia a relação da acuidade visual obtida pelo PAM no período pré-operatório da cirurgia de catarata com a melhor acuidade visual obtida no pós-operatório, bem como, sua relação com a classificação morfológica dominante da catarata e sua intensidade de opacificação quando do tipo nuclear.…”

Section: Resumo Introduçãounclassified