JH Seo, et al. ASSESSMENT OF FUNCTIONAL VISION SCORE IN RP Table 1. Classification of functional vision score11 Class Description Estimated ability to perform activities of daily living 1 Range of normal vision Retained reserve capacity 2 Near-normal vision Lost reserve capacity 3 Moderately low vision Need for visual enhancement of aids 4 Severely low vision Slower than normal, even with enhancement aids 5 Profoundly low vision Marginal visual performance, even with aids 6 Total blindness Cannot perform, needs substitution aids FVS=functional vision score according to AMA guides. Source: Guides to the evaluation of permanent impairment, fifth edition, copyright 2001, American Medical Association. FVS (points) >90 71-90 51-70 31-50 11-30 <10 Table 2. Demographic and clinical characteristics of enrolled patients (n=108) Variables Mean±SD (Range) Variable n, (percent) Age (years) 37.6±13.0 (13.0-85.0) Gender (male %) 65, (60.1 %) Disease duration (years) 19.1±12.9 (1-58 ) FVS Class distribution 4.9±0.8 (1-6) Onset age (years) 19.0±14.9 (1-80 ) 1 0, (0 %) BCVA OD 0.81±0.68 (0.0-2.3) 2 0, (0 %) OS 0.78±0.68 (0.0-2.3) 3 5, (4.6 %) BCVA better eye 0.63±0.58 (0.0-2.3) 4 23, (21.3 %) FVS 21.3±16.1 (0.0-68.5) 5 50, (46.3 %) FFS 29.7±17.1 (0.8-69.2 ) 6 30, (18.5 %) FAS 65.3±27.9 (0.0-100.0 ) NEI-VFQ General vision 37.2±17.6 (0.0-80) Ocular pain 71.3±24.9 (0.0-100) Near vision 55.6±29.3 (8.3-100) Distant vision 49.2±22.7 (0.0-91.7) Vision-specific social function 61.9±26.3 (12.5-100) Vision-specific mental health 42.3±26.2 (0.0-100) Vision-specific role difficulty 39.7±30.5 (0.0-100) Vision-specific dependency 58.6±27.0 (0.0-100) Driving 57.5±28.9 (0.0-100) Color vision 72.5±30.7 (0.0-100) Peripheral vision 46.3±25.8 (0.0-100) Composite score 50.8±19.8 (14.6-95.9) FVS=functional vision score; FFS=functional field score; FAS=functional acuity score; NEI-FVQ=National Eye Institute’s Visual Functioning Questionnaire. evaluation according to the parameters of the International Society for Clinical Electrophysiology of Vision (ISCEV). Patients with hearing impairment (Usher syndrome) or other systemic diseases were excluded. However, patients with rea- ding difficulties due to low vision were not excluded. The re- searchers assisted these patients in completing the question- naires. Patients were given the option of dropping out of the study. Our Institutional Review Board (IRB) approved the study protocol, informed consent was obtained from all of the sub- jects, and all procedures used were consistent with the tenets of the Helsinki Declaration. All of the patients underwent a thorough ophthalmic examination including best-corrected vi- sual acuity (BCVA), binocular indirect ophthalmoscopy, fundus examination, and Goldmann perimetry. If a definite diagnosis of RP could not be made, a standard electroretinogram was performed for confirmation. Visual acuity measurement and visual field examination The BCVA was measured using Snellen Visual Acuity Charts and was converted into a logarithm of the minimum angle of resolution (log MAR) VA scale. Monocular visual fields were measured by Goldmann perimetry using the Ⅲ-4-e target at a standard luminance. Along each meridian, the target was pre- sented from a position of non-seeing to seeing, moving clock- wise. All of the BCVA and perimetry measurements were per- formed by skilled technicians. Functional assessment according to the guidelines The AMA has published guidelines10,11 for the evaluation of permanent impairment. The FVS was calculated from the functional acuity score (FAS) and the functional field score 165