The Great Ormond Street occlusion protocol for bilateral and unilateral cataracts
| Occlusion regime for bilateral cataract | Occlusion regime for unilateral cataract |
| (1) 0–1/2 octaves interocular difference in visual acuity, no occlusion | (1) The phakic eye is occluded 1hour/day for each month of life until 6 months of age. After 6 months occlusion depends on interocular difference (see 2–4 below) |
| (2) 1–2 octaves interocular difference in visual acuity, 1–2 hours of occlusion of the preferred eye | (2) 0–½ octave interocular difference in visual acuity, 50% of waking hours |
| (3) More than 2 octaves interocular difference in visual acuity, 2–4 hours of occlusion of the preferred eye | (3) 1–2 octaves interocular difference in visual acuity, 75% of waking hours |
| (4) If no improvement after stage 3, full time occlusion | (4) More than 2 octaves interocular difference in visual acuity, 100% waking hours |
| NB To be reviewed every 2 weeks | NB To be reviewed every 2 weeks |
↵That is, a child aged 2 months is patched for 2 hours a day, a 3 month old child for 3 hours/day, etc.