The Optometric Exam and Basic Ocular Anatomy

Vocabulary terms and definitions covering the structure of the optometric exam, ocular anatomy, landmarks, and basic clinical optics.

Chief Complaint

A list of problems the patient is experiencing; it is the first piece of data collected in the exam and represents what brought the patient to see the provider.

Case History

Includes follow up questions pertaining to the chief complaint and all other relevant information pertaining to the patient’s ocular and systemic health.

SOAP

The format for a medical exam record consisting of Subjective, Objective, Assessment, and Plan.

Assessment

A bulleted list of diagnoses, including the specific eye involved, which must address the patient’s chief complaint.

Plan

A bulleted list addressing therapeutic intervention, patient education, and "Return To Clinic" (RTC) information for each assessment.

Canthus

The location where the superior and inferior lids meet; categorized into Medial (Nasal) and lateral canthus.

Limbus

The corneal/scleral junction that runs $360$ degrees around the eye.

Caruncle

Fleshy modified epidermal tissue located in the medial canthus that often contains pigmentation and hair.

Nasal (Medial)

Anatomical orientation towards the nose.

Temporal (Lateral)

Anatomical orientation towards the temple.

Anterior (Orientation)

Towards the front; includes all ocular structures in front of and including the lens.

Posterior (Orientation)

Towards the back; includes all ocular structures behind the lens.

Meibomian glands

Glands located in the posterior portion of the lid that secrete the lipid layer of the tear film.

Orbicularis Oculi

The muscle responsible for gentle and forceful closure of the eye, innervated by cranial nerve 7 ($CN 7$).

Superior Palpebral Levator

The muscle responsible for the elevation of the lid; it acts as the antagonist to the palpebral part of the orbicularis oculi.

Conjunctiva

A thin, vascularized mucous membrane that lines the posterior portion of the lids and terminates at the limbus.

Goblet cells

Cells located in the conjunctiva that secrete the mucin layer of the tear film to stabilize it.

Emmetropization

The process in which the eye undergoes changes during development in children to achieve clear vision at distance.

Corneal deturgescence

The optimal corneal hydration level of $75-80\%$ water (specifically $78\%$ water content) maintained by $NA/K$ pumps in the endothelium.

Dilation

The widening of the pupil regulated by the iris.

Miosis

The constriction of the pupil regulated by the iris.

Aqueous humor

Fluid produced by the ciliary body that flows through the pupil and out the drainage mechanism into the venous system.

Accommodation

The process where the lens and ciliary body allow the eye to focus on near objects.

Macula

Area of the retina comprised of the highest density of photoreceptors, responsible for the sharpest level of visual acuity.

Fovea

A parabolic depression in the center of the macula located in a capillary-free zone to allow unobstructed light to reach photoreceptors.

Optic Nerve

A donut-shaped structure formed from the gathering of all nerve fibers of the retina.

Objective refraction

The process of obtaining a patient's prescription using methods like Retinoscopy without requiring patient responses.

Subjective refraction

The process of obtaining a patient's prescription where the patient is given the chance to respond to tentative options (e.g., "Which is better, one or two").

Vergence

The reciprocal of the distance from a reference point in meters to the light source or focal point ($V = \frac{1}{d}$), measuring the convergence or divergence of light rays.

Optical Infinity

A distance of $20\,\text{feet}$ ($6\,\text{meters}$) or greater, at which light rays are considered parallel with zero vergence.

Diopter

The unit of measurement for the vergence of light and the refracting power of lenses.

Plus Lens

Also called a convex lens; it converges light, has a positive secondary focal point, and is used to correct Hyperopia.

Minus Lens

Also called a concave lens; it diverges light, has a negative secondary focal point, and is used to correct Myopia.

Prism

A wedge-shaped optical device with an apex and a base; it bends light towards the base and moves the image towards the apex without affecting vergence.