Contributions
Abstract: P834
Type: Poster
Abstract Category: Clinical aspects of MS - Paediatric MS
Introduction: Low-contrast letter acuity (LCLA) is increasingly recognized as a sensitive measure of visual impairment in paediatric multiple sclerosis and optic neuritis. LCLA requires identification of letters based on the visual angle to determine acuity, but it is also a task of perception given its faint gray letters on a white background. While high-contrast letter acuity is established by age 6 years (visual acuity of 20/20), maturation of the visual pathways and cortex occur throughout childhood. Therefore, it is unknown whether LCLA scores change as a function of age. The goal of the present study is to determine normative values for low-contrast letter acuity in healthy children.
Methods: Healthy controls (without evidence of ocular or neurologic disease) between the ages of 4 and 21 were recruited for this study if their best-corrected visual acuity was 20/20 or better on Early Treatment Diabetic Retinopathy Study letter charts. Using retro-illuminated box charts, participants completed 2.5% and 1.25% Sloan LCLA charts; monocular and binocular scores (total number of letters correctly identified) were recorded. Mean values by age were calculated. Loess and spline regression models were used to compare scores by age.
Results: A total of 95 healthy controls were recruited, contributing 190 eyes for the analysis. Overall, older children correctly identified more letters than younger children. A spline regression with 3 knots identified a change at age 13.9 years. For example, mean 2.5% LCLA scores for ages 5-6 years were 27.0 letters (SD 3.2, range 20.7-33.3) compared to 35.2 letters (SD 1.8, range 31.6-38.7) at 13-14 years and remained stable thereafter. For 1.25% contrast, mean LCLA scores also increase from 18.5 letters correct (SD 2.2, range 14.2-22.8) at ages 5-6 years to 25.6 letters (SD 1.8, range 22.0-29.2) at ages 13-14 years. Right and left monocular as well as binocular testing produced similar results. Gender differences did not significantly impact the subject"s scores.
Conclusion: Healthy children"s ability to detect low-contrast letters increases until age 13.9 years and then remains relatively stable into early adulthood. These results should be considered in the design of future paediatric studies incorporating low-contrast letter charts. Similarly, LCLA has also been considered as a fourth measure for the Multiple Sclerosis Functional Composite; such studies should also incorporate age into the analysis in paediatric cohorts.
Disclosure: Amy Waldman: Dr. Waldman is currently funded by the National Institutes of Health (USA) and receives research support from Biogen Idec. She is also the site-PI for a clinical trial sponsored by Novartis, who has also provided travel reimbursement for study meetings. Prior research funding was provided by the National Multiple Sclerosis Society and the American Brain Foundation.
Amy Lavery: nothing to disclose
Geraldine Liu: nothing to disclose
Brenda Banwell: Dr. Banwell serves as a consultant for Novartis, and as an unpaid advisor on clinical trial design for Sanofi, Teva Neuroscience, and Biogen IDEC.
Abstract: P834
Type: Poster
Abstract Category: Clinical aspects of MS - Paediatric MS
Introduction: Low-contrast letter acuity (LCLA) is increasingly recognized as a sensitive measure of visual impairment in paediatric multiple sclerosis and optic neuritis. LCLA requires identification of letters based on the visual angle to determine acuity, but it is also a task of perception given its faint gray letters on a white background. While high-contrast letter acuity is established by age 6 years (visual acuity of 20/20), maturation of the visual pathways and cortex occur throughout childhood. Therefore, it is unknown whether LCLA scores change as a function of age. The goal of the present study is to determine normative values for low-contrast letter acuity in healthy children.
Methods: Healthy controls (without evidence of ocular or neurologic disease) between the ages of 4 and 21 were recruited for this study if their best-corrected visual acuity was 20/20 or better on Early Treatment Diabetic Retinopathy Study letter charts. Using retro-illuminated box charts, participants completed 2.5% and 1.25% Sloan LCLA charts; monocular and binocular scores (total number of letters correctly identified) were recorded. Mean values by age were calculated. Loess and spline regression models were used to compare scores by age.
Results: A total of 95 healthy controls were recruited, contributing 190 eyes for the analysis. Overall, older children correctly identified more letters than younger children. A spline regression with 3 knots identified a change at age 13.9 years. For example, mean 2.5% LCLA scores for ages 5-6 years were 27.0 letters (SD 3.2, range 20.7-33.3) compared to 35.2 letters (SD 1.8, range 31.6-38.7) at 13-14 years and remained stable thereafter. For 1.25% contrast, mean LCLA scores also increase from 18.5 letters correct (SD 2.2, range 14.2-22.8) at ages 5-6 years to 25.6 letters (SD 1.8, range 22.0-29.2) at ages 13-14 years. Right and left monocular as well as binocular testing produced similar results. Gender differences did not significantly impact the subject"s scores.
Conclusion: Healthy children"s ability to detect low-contrast letters increases until age 13.9 years and then remains relatively stable into early adulthood. These results should be considered in the design of future paediatric studies incorporating low-contrast letter charts. Similarly, LCLA has also been considered as a fourth measure for the Multiple Sclerosis Functional Composite; such studies should also incorporate age into the analysis in paediatric cohorts.
Disclosure: Amy Waldman: Dr. Waldman is currently funded by the National Institutes of Health (USA) and receives research support from Biogen Idec. She is also the site-PI for a clinical trial sponsored by Novartis, who has also provided travel reimbursement for study meetings. Prior research funding was provided by the National Multiple Sclerosis Society and the American Brain Foundation.
Amy Lavery: nothing to disclose
Geraldine Liu: nothing to disclose
Brenda Banwell: Dr. Banwell serves as a consultant for Novartis, and as an unpaid advisor on clinical trial design for Sanofi, Teva Neuroscience, and Biogen IDEC.