Abstract
Purpose: :
It has been previously shown that stand-mounted closed circuit television (CCTV) technology was preferred over spectacle lenses, optical magnifiers and hand held CCTV’s for the purpose of reading and writing. This study compares performance between a stand-mounted CCTV device (Merlin) and a free space CCTV device(Acrobat). This type of comparison has previously not been performed. Having a standardized comparison of two instruments utilizing different approaches in design and capabilities will be beneficial both to doctors and patients in deciding which device is better suited for visually impaired patients
Methods: :
Prior to entering the study, IRB approved informed consent was obtained from each patient. Eleven patients with best corrected visual acuity of less than 20/160 to 20/400 in the better seeing eye who were first time electronic magnification users, received training for 30 min on both the Merlin and Acrobat instruments.The patients were then asked to complete three tasks of daily living. The tests were spot reading (pill bottles, bank statement), continuous reading (Visagraph texts of 115 words) and writing (grocery lists). All tasks were timed and a survey was given at the end to check for preferences. The order of devices, texts and lists was randomized.
Results: :
Timed responses for spot reading: Acrobat times were 4.2% faster for pill bottle and 3.8 % faster for bank statement; continuous reading timed responses were 5.8% faster on Merlin. Writing grocery list were 12.5% faster with the Acrobat. The survey indicated that ease of initial use, ability to spot information and reading documents had less than 5% variation between the two devices. In a survey 72% of the patients preferred Acrobat for writing. When asked which device they would personally purchase 72% chose Acrobat.
Conclusions: :
Both subjectively and objectively Acrobat was statistically equal to Merlin in spot reading and continuous reading and preferred for writing.
Keywords: low vision • aging: visual performance • reading