Her memory of the room is now her eyesight
A cat who has lived in your home for years already knows it by more than vision. She counts steps between the sofa and her water bowl, follows the edge of a rug with her paws, and uses scent marks she has left on door frames and chair legs to confirm where she is. As sight fades, that memorised map becomes her main way of moving safely and confidently. This is why consistency matters so much: a dining chair left pulled out, a laundry basket in the hallway, or a litter box shifted to a different corner can strand her, because the obstacle or the missing landmark does not match the map she trusts.
Set a fixed layout and protect her routes
Choose the layout that already works and commit to it. Her bed, litter box, food, and water should stay in their long-standing places, on the same floor if possible, so she does not need stairs for essentials. Walk the routes between those points yourself and remove anything she could collide with at head or body height: shoes in the corridor, bags by the door, a child's toys scattered across the landing. Keep doors either fully open or fully closed rather than half-ajar, because a half-open door sits where her map expects either a wall or a gap. If you must move something large, do it while she is in another room and then guide her, on foot and at her pace, along the changed route several times.
Use sound, scent, and touch to fill the gaps
Talk to her as you move around the house so your voice gives her a moving landmark, and speak before you stroke or lift her so a hand never arrives without warning. A small bell on another pet's collar can help her track a companion, and leaving a worn item of your clothing near her bed gives her a familiar scent anchor in the place she rests. Avoid picking her up and setting her down in a different spot to save time; being carried disorients a blind cat because she cannot connect where she was with where she lands. If she calls out, answer her and go to her rather than calling her through unfamiliar obstacles toward you.
Make hazards safe without rearranging her world
Block the top and bottom of stairs with a gate until you know how she handles them, and fit a textured runner or mat at key thresholds so her paws tell her which room she is entering. Cover sharp furniture corners on her main routes at her head height, keep toilet lids down, and close off rooms she rarely uses rather than expecting her to map the whole house. Night lights along her route to the litter box help if she retains some vision in dim light, and they cost her nothing if she does not. Any new item, such as a scratching post, should be introduced in place beside an existing landmark and left there permanently once she has learned it.
Check in with your vet about the change itself
Vision loss in a senior cat should always be discussed with a vet, even when she is coping well at home. Book promptly if the change seemed sudden, if one eye looks cloudy, enlarged, or painful, if she is bumping into things she managed last week, or if she also seems disoriented in other ways, such as getting stuck in corners. Note when you first saw her hesitate, misjudge a jump, or track a toy less accurately, and whether evenings are harder than mornings. Your vet can check her eyes and general health, and your observations about how she moves at home are a real part of that picture.
The relatives you name — perhaps a daughter who feeds her when you travel — receive access to her profile under KinsLe Family Sharing, while everyone else stays outside that arrangement.