Jill Woods, BSc, MOptom is a Clinical Scientist at the Centre for Contact Lens Research at the University of Waterloo’s School of Optometry, in Canada.Download the poster (.pdf), which was originally shared at the American Academy of Optometry’s annual meeting, 2011.
Jill Woods, Nancy J. Keir, Craig A. Woods, Desmond Fonn, Centre for Contact Lens Research, University of Waterloo, Canada
Purpose: To compare performance, adaptation and preference between a multifocal and a monovision correction among contact lens wearers requiring a medium reading-addition (+1.25 to +2.00).
Method: Participants were enrolled into a randomised, cross-over study; all lenses were manufactured from Lotrafilcon B. Following screening and a one-week wash-out (distance contact lenses and reading spectacles) they wore the multifocals for two weeks and the monovision for two weeks. Objective vision tests were conducted at dispense and two-week visits with each modality. Subjective ratings were collected after specific tasks: reading, driving, computer use, television viewing and shopping. Questionnaires were completed on days 3, 7, 12 and 14 to assess adaptation and preference.
Results: forty-nine participants completed the study. The driving task questions showed several statistically higher (p<0.05) ratings for the multifocal correction. Other tasks showed little difference between the corrections. For objective assessments, all except intermediate low-contrast acuity and near stereopsis were statistically better (p<0.05) with monovison compared to multifocal correction. The adaptation questionnaire did not show a significant difference between corrections on days 3, 7 and 12 (p>0.05). The preference questions at the final visit indicated that 28 participants preferred multifocal correction and 21 preferred monovision correction. Though preference was not statistically significant, the reported reasons for this preference will be presented along with data on changes in preference from current correction type.
Conclusions: LogMAR acuity results were generally better with monovision whereas subjective ratings and preference responses either demonstrated a higher rating for the multifocal modality or no difference. This supports previous reports that subjective assessments are more effective than traditional vision testing to indicate overall multifocal performance. Adaptation to each modality appeared complete by three days, suggesting benefit to minimum three-day trials.
