You qualify for a free NHS funded sight test if you are:
Aged under 16, or aged under 19 and in full-time education
Aged 60 or over
Registered blind or partially sighted
Diagnosed with diabetes or glaucoma
Aged 40 or over and you are the parent, brother, sister, son or daughter of a person diagnosed with glaucoma, or you have been advised by an ophthalmologist that you are at risk of glaucoma
Eligible for an NHS complex lens voucher
You are also entitled to a free NHS sight test if you or your partner receive:
Income Support or Income-based Jobseeker’s Allowance (not contribution based)
Pension Credit Guarantee Credit
Income-based Employment and Support Allowance
Awarded Universal Credit
Entitled to, or named on, a valid NHS tax credit exemption certificate
Named on a valid NHS certificate for full help with health costs (HC2)
People named on an NHS certificate for partial help with health costs (HC3) may also get help.
Also read about the NHS Low Income Scheme (LIS).