Table 2. Total and domain BIC-11 scores for caregivers by patient treatment and visual impairment (better-seeing eye) categories.
| Domain, Mean (SD) | |||||||
|---|---|---|---|---|---|---|---|
| Time-dependent burden | Emotional burden | Existential burden | Physical burden | Service-related burden | Personal estimate of overall burden | Total score | |
| Treatment category* | |||||||
| PRN to T&E switchers (n = 18) | 1.17 (2.23) | 1.00 (1.81) | 1.22 (1.96) | 0.61 (1.69) | 0.72 (1.74) | 0.61 (0.98) | 5.33 (9.40) |
| T&E (n = 42) | 1.21 (1.59) | 0.79 (1.22) | 0.81 (1.31) | 0.60 (0.99) | 0.40 (0.70) | 0.48 (0.63) | 4.29 (5.49) |
| PRN (n = 10) | 1.40 (0.97) | 0.80 (1.03) | 0.80 (1.03) | 0.40 (0.84) | 0.80 (1.03) | 0.40 (0.70) | 4.60 (4.74) |
| Patient’s actual visual impairment category1** | |||||||
| Blindness (<20 letters) (n = 4) | 2.00 (2.31) | 1.25 (1.89) | 2.00 (1.63) | 1.00 (1.15) | 1.00 (1.15) | 0.75 (0.50) | 8.00 (7.87) |
| Severe visual impairment (≥20–<35 letters) (n = 0) | — | — | — | — | — | — | — |
| Moderate visual impairment (≥35–<58 letters) (n = 3) | 0.67 (1.15) | 0.67 (1.15) | 0.67 (1.15) | 0 | 0.67 (1.15) | 0.67 (1.15) | 3.33 (5.77) |
| Some visual impairment (≥58–<70 letters) (n = 9) | 1.78 (1.92) | 1.22 (1.79) | 0.89 (1.45) | 0.67 (1.00) | 0.56 (0.73) | 0.67 (0.71) | 5.78 (6.61) |
| Mild visual impairment (≥70–<80 letters) (n = 10) | 2.10 (2.69) | 1.60 (2.22) | 1.80 (2.57) | 0.90 (2.23) | 1.30 (2.21) | 0.80 (1.14) | 8.50 (11.76) |
| No visual impairment (≥80 letters) (n = 41) | 0.90 (1.24) | 0.56 (0.87) | 0.63 (1.02) | 0.44 (0.90) | 0.29 (0.64) | 0.34 (0.62) | 3.17 (4.30) |
| Caregiver’s rating of patient’s visual acuity** | |||||||
| Mild (n = 26) | 1.15 (1.59) | 0.77 (0.99) | 0.81 (1.20) | 0.42 (0.90) | 0.38 (0.75) | 0.35 (0.63) | 3.88 (4.91) |
| Moderate (n = 35) | 1.09 (1.46) | 0.69 (1.16) | 0.71 (1.13) | 0.49 (0.89) | 0.46 (0.78) | 0.54 (0.82) | 3.97 (5.14) |
| Severe (n = 10) | 1.80 (2.53) | 1.50 (2.42) | 1.80 (2.57) | 1.20 (2.20) | 1.20 (2.20) | 0.70 (0.67) | 8.20 (12.10) |
Domain score for “personal estimate of overall burden” ranges from 0 to 4. Scores for other domains ranges from 0 to 8. Total scores ranges from 0 to 44. Higher score indicates greater burden. BIC-11, Burden Index of Caregivers-11; PRN, as-needed; SD, standard deviation; T&E, treat-and-extend.
1Visual impairment is defined according to World Health Organization categories (WHO, 2016) [28].
*p = not significant between treatment groups (switcher vs. PRN or T&E, T&E vs. PRN) for total and subscale scores (unpaired t test).
**p = not significant for total and subscales scores and worsening visual impairment (trend test).