BCLA CLEAR - Anatomy and physiology of the anterior eye

Abstract

A key element of contact lens practice involves clinical evaluation of anterior eye health, including the cornea and limbus, conjunctiva and sclera, eyelids and eyelashes, lacrimal system and tear film. This report reviews the fundamental anatomy and physiology of these structures, including the vascular supply, venous drainage, lymphatic drainage, sensory innervation, physiology and function. This is the foundation for considering the potential interactions with, and effects of, contact lens wear on the anterior eye. This information is not consistently published as academic research and this report provides a synthesis from all available sources. With respect to terminology, the report aims to promote the consistent use of nomenclature in the field, and generally adopts anatomical terms recommended by the Federative Committee for Anatomical Terminology. Techniques for the examination of the ocular surface are also discussed.

BCLA CLEAR - Evidence-based contact lens practice

“…A thorough examination of the anterior eye is required prior to fitting contact lenses and at each aftercare visit. The assessment requires a combination of different slit lamp biomicroscopy techniques [126] to evaluate the fit of the contact lens (section 5), anterior eye anatomy (see CLEAR Anatomy Report and CLEAR Material Impact Report) [127,128] and the health of the eye, and the use of ophthalmic dyes to monitor the eye for contact lens complications (section 7.4 and see CLEAR Complications Report) [38]. The least invasive tests in terms of illumination intensity, lid manipulation and dye application, should be performed first.…”

“…The tear film is an essential component in contact lens wearing comfort [139] and can impact contact lens drop out (section 7.3 and see CLEAR Maintenance Report and CLEAR Anatomy Report) [127,140]. Consequently, an appropriate examination of the tear film, the ocular surface and quantification of symptoms, is vital in contact lens fitting and aftercare [14,141].…”

“…The palpebral conjunctiva must be evaluated for redness and papillae/follicles at each visit (see CLEAR Anatomy Report) [127]. The grading of palpebral roughness is significantly higher when assessed with fluorescein and blue light rather than under white light [158].…”

“…The lid margins should be examined to identify anterior blepharitis [142], meibomian gland dysfunction [165], lid-parallel conjunctival folds and lid-wiper epitheliopathy [11,78,166] (see CLEAR Anatomy Report) [127].…”

“…Lid-parallel conjunctival folds (LIPCOF) are small folds in the inferior-temporal and inferiornasal bulbar conjunctiva, which are aligned parallel to the lower lid [167] (see CLEAR ANATOMY Report) [127]. LIPCOF are visible with a slit-lamp biomicroscope and white light at magnifications of 18x [53,167] to 25x [168].…”