OBJECTIVES: The defocused portion of the image obtained in wearers of bifocal and multifocal contact lenses often appears as a "ghost." Relatively few methods exist to quantify the ghosting perceived with lenses. The purpose of this study is to validate and implement a questionnaire to help patients quantify the ghost images perceived with bifocal or multifocal corrections. METHODS: Ten subjects viewed simulated bifocal vision images displayed on a monitor. Images contained a focused and a defocused (ghost) component of a specific dimension (direction, position offset, intensity, and focus). Using a test card, the subjects identified the ghosting dimension level displayed on the monitor. An additional 54 presbyopic subjects wearing a multifocal correction monocularly viewed a well-focused stimulus and then compared the perceived image to that of the other well-corrected eye looking at the ghosting test card to quantify their visual experience of the 4 proposed ghosting dimensions. RESULTS: Regardless of ghost letter size and orientation, subject responses were within 1 rating unit of expected on >95% of all trials for all 4 dimensions when asked to directly match a single dimension of ghosting. With bifocal images containing random amounts of these 4 dimensions most response errors were also within ± 1 unit. In presbyopes wearing a multifocal lens, the focus dimension was most strongly associated with overall ratings of ghosting. CONCLUSIONS: The subjects can accurately and reliably report on ghost intensity, focus, direction and position offset, and well-focused ghosts are most correlated with the overall perceptual saliency of ghosting.
OBJECTIVES: The defocused portion of the image obtained in wearers of bifocal and multifocal contact lenses often appears as a "ghost." Relatively few methods exist to quantify the ghosting perceived with lenses. The purpose of this study is to validate and implement a questionnaire to help patients quantify the ghost images perceived with bifocal or multifocal corrections. METHODS: Ten subjects viewed simulated bifocal vision images displayed on a monitor. Images contained a focused and a defocused (ghost) component of a specific dimension (direction, position offset, intensity, and focus). Using a test card, the subjects identified the ghosting dimension level displayed on the monitor. An additional 54 presbyopic subjects wearing a multifocal correction monocularly viewed a well-focused stimulus and then compared the perceived image to that of the other well-corrected eye looking at the ghosting test card to quantify their visual experience of the 4 proposed ghosting dimensions. RESULTS: Regardless of ghost letter size and orientation, subject responses were within 1 rating unit of expected on >95% of all trials for all 4 dimensions when asked to directly match a single dimension of ghosting. With bifocal images containing random amounts of these 4 dimensions most response errors were also within ± 1 unit. In presbyopes wearing a multifocal lens, the focus dimension was most strongly associated with overall ratings of ghosting. CONCLUSIONS: The subjects can accurately and reliably report on ghost intensity, focus, direction and position offset, and well-focused ghosts are most correlated with the overall perceptual saliency of ghosting.
Authors: Daniel Tilia; Anna Munro; Jiyoon Chung; Jennifer Sha; Shona Delaney; Danny Kho; Varghese Thomas; Klaus Ehrmann; Ravi Chandra Bakaraju Journal: J Optom Date: 2016-05-07
Authors: Ravi C Bakaraju; Daniel Tilia; Jennifer Sha; Jennie Diec; Jiyoon Chung; Danny Kho; Shona Delaney; Anna Munro; Varghese Thomas Journal: J Optom Date: 2017-06-12
Authors: Julia S Benoit; Ayeswarya Ravikumar; Jason D Marsack; Heather A Anderson Journal: Transl Vis Sci Technol Date: 2020-04-15 Impact factor: 3.283
Authors: Laura Remón; Pablo Pérez-Merino; Rute J Macedo-de-Araújo; Ana I Amorim-de-Sousa; José M González-Méijome Journal: J Ophthalmol Date: 2020-03-27 Impact factor: 1.909