Diagnosed with unilateral cataract. Suggested to wear patch. Does patching compromise sight in good eye?

The number of hours in the day patching needs to be done has no consensus however with the time needed based on the severity of amblyopia in the eye. There is a chance of the other eye becoming 'lazy' but that is why routine follow up is needed. The other eye vision is always noted to avoid this eventuality. At home as well, you need to observe your grand daughter when the other eye is open to make sure she has comfortable vision in both eyes and there is no deviation of the eye position. Along with patching, the child is made to perform certain tasks to develop binocular vision and depth perception which is probably explained to you by your treating doctor. Patching during sleep does not help since both there is no visual stimulus.
How long you patch the eye will reduce as she shows improvement. It is difficult but has to be done and will be terminated when benefit is reached.

Occlusion is necessary for amblyopia. There is actually a curriculum as per age like one day on one day off for 1yr old. 2days on & 1 day off for 2yr old and so on as per Amplyopia treatment study . So one day occlusion and one day off should help. Orelse you might try 2hrs a day....the study says that helps too. BUT It has 2 walking hours not sleep hours. Make her see colorful things like colored balls or toys... only then will it help.