7. Yn rheoliad 2 o Reoliadau 1986 (dehongli), caiff y canlynol ei fewnosod yn y lle priodol yn nhrefn yr wyddor—
““day centre” means an establishment attended by patients who would have difficulty in obtaining general ophthalmic services from practice premises because of physical or mental illness or disability or because of difficulties in communicating their health needs unaided;
“mobile practice” means a contractor who does not have practice premises in a locality, but who has undertaken to provide general ophthalmic services at day or residential centres in that locality;
“residential centre” means an establishment for patients who normally reside in that establishment and who are unable to leave the establishment unaccompanied because of physical or mental illness or disability.”.