I'm not a teacher but I'm the parent of a Y7 new starter who is now registered blind, following a very rapid and unexpected deterioration in her sight.
Your SEND department needs to put in an urgent referral to your local specialist inclusion unit, so your young person can be put on the active caseload of a Qualified Teacher for the Vision Impaired. The QTVI will come into school, assess your student's individual needs, and recommend the necessary adjustments school has to make in order for the child to be able to access their learning, and the full curriculum. It may be that an Habilitation specialist (they help people with disabilities/impairments with everyday functional/living skills) will also be brought into school in order to assess how your student can safely navigate the campus (it goes without saying that crowded corridors are an accident waiting to happen for children and young people with vision impairments) or help them to learn to touch type, for example. These specialists will help with a referral to your nearest Low Vision clinic which provides equipment such as reading magnifiers to partially sighted and severely sight impaired people.
As mentioned above, the RNIB is a magnificent support to families and schools supporting VI children and there is a wealth of information for teachers on its website.
It's interesting to note that in many cases, just enlarging normal scripts actually disables VI students even more as they're cumbersome, unwieldy (and, in my daughter's case, shaming as they draw extra attention to her difference.
I would also like to recommend that your student accesses a current offer, funded by an organisation called VICTA and administered by the RNIB, for a FREE iPad Air (or Braille reader). You can download a grant application form on the VICTA website, send off proof off registration as either partially sighted or legally blind, and, assuming the grant request is approved, the RNIB will courier the equipment to the student's home, using the Royal Mail Articles for the Blind scheme. The QTVI can then adjust the settings to your student's specific print size/font/anti-glare/colour background preferences and Bob's your uncle!
My daughter's teachers email her lessons in advance of each class, they have very specific instructions on how/where she should be seated in class, release her 5 minutes before each bell so she can navigate the corridors safely and (best of all, obviously) she gets to jump the lunch queue every day!
I will come back on if I can think of anything else useful but I'm off now to collect her from the school bus.
But one final thing, your student, once registered, will automatically qualify for 100 per cent extra time in all exams.