2. Summary of analysis of visual outcomes (visual field and visual acuity) in included trials.
| Outcome | Berson 1993 | Berson 2004 | Hoffman 2004 | |
| Visual field | Instrument used | Goldmann perimeter (V‐4‐e white test light) | Humphrey field analyzer 30‐2 program | 640 Humphrey field analyzer, Program 30‐2 |
| Effect measure | Percent decline per year of remaining visual field area | Mean annual rate loss of field sensitivity | Mean change in defect in Humphrey spot size III field from baseline at 4 years | |
| Method used for estimation | Longitudinal regression analysis | Longitudinal regression analysis | Mean change from baseline | |
| Estimate | Vitamin A + vitamin E
trace = 5.6% Vitamin A + vitamin E = 6.2% Vitamin A trace + vitamin E trace = 5.9% Vitamin A trace + vitamin E = 6.3% |
DHA + vitamin A = 36.95 ± 3.36
dB/year Control + vitamin A = 37.68 ± 3.36 dB/year |
DHA = 2.4 ± 3.66 dB (0.24 logMAR) Placebo = 1.4 ± 1.32 dB (0.14 logMAR) | |
| Data interpretation | No significant vitamin A or vitamin E main effects or interaction effects were observed |
No significant difference | No significant difference | |
| Visual acuity | Instrument used | EDTRS chart | EDTRS chart | EDTRS chart |
| Effect measure | Number of EDTRS letters lost per year |
Annual rate of decline of EDTRS visual acuity over 4 years | Mean group difference in log MAR visual acuity between years 0 and 4 for the average of both eyes | |
| Method used for estimation | Longitudinal regression analysis | Longitudinal regression analysis | Mean change from log MAR baseline visual acuity | |
| Estimate | Vitamin A + vitamin E
trace = 1.1 letters/year Vitamin A + vitamin E = 0.7 letters/year Vitamin A trace + vitamin E trace = 0.9 letters/year Vitamin A trace + vitamin E = 0.9 letters/year |
DHA + vitamin A = 0.71 + 0.12
letters/year Control + vitamin A = 0.68 + 0.12 letters/year |
DHA = 0.05 ± 0.23 log
units (logMAR) Placebo = 0.06 ± 0.2 log units (logMAR) |
|
| Data interpretation | No significant difference | No significant difference | No significant difference |
DHA: docosahexaenoic acid
EDTRS: Early Treatment Diabetic Retinopathy Study
RCT: randomized controlled trial