Enhanced Eye Services are those which fall outside the normal eye examination.
There are several schemes funded by the NHS which require accreditation of the optician who provides it. Examples are:-
Cataract pre-op assessment
Cataract post-op assessment
PEARS (for acute eye problems where A&E may not be appropriate)
Glaucoma suspect referral refinement
Children's school referral
HOLOMS (monitoring stable glaucoma)
Repeat pressure and field tests
Wet AMD fast track referral
Note, the scope of these services vary as to which county your GP serves in. However, Herefordshire and Shropshire have set up more schemes than most areas.