Pupils, cover test and ocular motility

Pupils, Cover Test, and Ocular Motility
Learning Objectives

By the end of this topic, you should be able to:

●​ Perform a full pupil examination step-by-step.
●​ Diagnose pupil abnormalities such as:
○​ Horner’s Syndrome
○​ Adie’s Tonic Pupil
○​ Argyll Robertson Pupil
○​ Relative Afferent Pupillary Defect (RAPD)
●​ Distinguish physiological vs pathological anisocoria.
●​ Record and interpret pupil responses accurately.
●​ Perform and record both cover and alternate cover tests.
●​ Carry out ocular motility tests, record findings, and interpret diplopia patterns.




Routine
Case history

-​ Current needs
-​ Relevant background

Preliminaries

-​ Vision / VA, cover test
-​ Motility pupils

Examination of eyes

-​ Slit lamp
-​ direct/indirect ophthalmoscopy



Pupils Assessment
Basic Anatomy and Function

●​ The pupil is an opening in the iris that regulates the amount of light entering the eye.
●​ Average diameter: 4–6 mm (reduces with age).

, Factors affecting pupil size

Increase in size Decrease in size

Physical and Luminance
emotional stress

Drugs Age

Drugs

Accommodation

Convergence




Control of Pupil Size


Function Nervous System Muscle Muscle Arrangement



Constriction (miosis) Parasympathetic Sphincter pupillae Circular



Dilation (mydriasis) Sympathetic Dilator pupillae Radial




Pupillary Pathway (Simplified)

●​ Afferent Pathway: Retina → Optic nerve → Pretectal nucleus → Edinger–Westphal
nucleus.
●​ Efferent Pathway: Edinger–Westphal nucleus → Oculomotor nerve (CN III) → Ciliary
ganglion → Sphincter pupillae.




Pupil Measurement

●​ Begin with general observation.
●​ Use a mm scale or pupillometer to measure horizontal visible iris diameter (HVID).