Upper level: b229 Seeing and related functions, other specified and unspecified
Functions of structures in and around the eye that facilitate seeing functions.
Inclusions: functions of internal muscles of the eye, eyelid, external muscles of the eye, including voluntary and tracking movements and fixation of the eye, lachrymal glands, accommodation, pupillary reflex; impairments such as in nystagmus, xerophthalmia and ptosis
Exclusions: seeing functions (b210); Chapter 7 Neuromusculoskeletal and Movement-related Functions
Lower livel:
b2158 Functions of structures adjoining the eye, other specified
b2159 Functions of structures adjoining the eye, unspecified