Hi!
Unfortunately, cataracts are not treatable in guinea pigs, but sight is thankfully the weakest of the guinea pig senses and they adopt well to the loss of it after a transition period. There are two kinds of cataract. the more common ones are old age cataracts, but some guinea pigs are also born with the disposition of developing cataracts at a young age (congenital cataracts); this generally happens during their second year of life but at the extreme a guinea pig can already be born with cataracts.
Just treat him like normal, but emphasise interaction and stimulation that appeals to the other senses - hearing, smell, touch etc.
Please give your boy an audio cue if you are touching him, picking him up and taking him somewhere; ideally create a little phrase with a special cadence for regular actions and also picture them in your mind. In my own experience with a number of cataract piggies, that helps a lot.
He has learned to compensate with his other senses by now and will orient himself by scent and touch. changing the layout is not a problem, as long as you do not wipe any furnishings clean. My cataract piggies were able to use shallow ramps as long as they were covered in a good scent holding material like a carpet offcut and had a little side rail. All my cataract ladies were up and down to the mezzanine and never had a dodgy moment.
My Mischief even learned to rebuild her mental map of the garden, did free-roam (under my supervision of course) and even learned to walk herself back into the run under her own steam as long as I was standing next to the flap and kept a steady stream of vocal feedback going as to whether she was going right or wrong. Occasionally she would suddenly veer off. If she got confused and could not reorient herself, I would go and pick her up, but more often than not, she could come to me over the distance of several yards. Of course, this didn't happen overnight and was a process that took several months. It also required a high level of trust from both sides.
Company would be great! If at all possible, I would recommend to rescue date your boy at a good standard rescue for a suitable gentle companion boar; not necessarily a baby.
In my own time, I had a dedicated cataract sow group from bereaved cataract sows that failed to integrate with the residential herd of not adoptable sows but bonded at my house over their shared disability. I never forget watching kind second-in-command Taffy, nearly blind with cataracts herself and on the brink of losing her position in the large Tribe group coming up to fear-agressive new arrival Tegyd and licking her badly affected cataract eye - that is one of the key moments I ever witnessed in with all my piggies. From that moment on, Tegyd was her best friend. When Tegyd struggled to cope with the big group, I split her and Taffy off and dated them with a gentle neutered boar at a local rescue. Unlike with the dominant Tribe boar, Tegyd clicked with the new boy instantly and they three because a very firmly bonded trio, later joined by another bereaved and 'unbondable' cataract sow in need of an emergency space due to a large multi-rescue action underway where every free rescue space was needed. As soon as Mali realised that the other two girls had the same disability as she had, she just fitted in and wanted to belong! Terfel devoted his life to looking after them all; he followed them to the Rainbow Bridge only three weeks after the last of wives had passed away.
A good rescue will be willing to help you find the perfect partner for your boy.
You can find pictures and videos of my cataract group and of their bonding in my singles guide:
Single Guinea Pigs - Challenges and Responsibilities
And also pictures with cataract piggies in my enrichment guide:
Enrichment Ideas for Guinea Pigs
Here are our boar and bonding guides, which you also may find helpful:
A Comprehensive Guide to Guinea Pig Boars
Bonding and Interaction: Illustrated social behaviours and bonding dynamics
You can find links to recommended vetted good standard rescues from several countries that allow you bring your boy for dating in several of the guides.
