Eye Anomalies as Diagnostic Indicators of Communication Disorders

Introduction

Although eyes occupy a prominent position in the human face, the information they can provide about presence of communication disorders often goes unnoticed during an oral-facial examination. Many speech-language pathologists (SLPs) associate eye examination with vision testing, and rightly believe that vision assessment does not fall within the responsibilities of a speech-language pathologist. Visual acuity, however, is only one aspect of eye examination. Eye orientation, color, and appearance can provide useful diagnostic information as to presence and type of communication disorders, particularly those disorders having hearing loss as a component. Observation of external eye appearance can yield information about health conditions such as otosclerosis; neurological disorders like Wilson's disease; first arch and mid-face anomalies including Treacher Collins and Crouzon; hearing loss due to genetic conditions like Waardenburg syndrome; and dual sensory disorders, such as CHARGE syndrome. This article describes several diagnostically significant anomalies of eye structure, but does not address anomalies of eye function, disorders of visual acuity, or eye muscle-related problems. This article also describes the relationships between external eye appearance and communication disorders, and suggests a simple protocol for observing, treating, and referring patients with eye anomalies.

External Eye Appearance

Ophthalmologic testing of vision requires medical certification and specific instrumentation to examine the health and intactness of internal structures, such as the lens, retina, and optic nerve. Limited visual examination of external eye appearance does not require special equipmentjust careful visual observational skills on the part of the examiner as well as knowledge of the relationship between anomalies of eye appearance and conditions that can affect the individual's health, nervous system, hearing, cognition, or vision. Examiners should become familiar with normal external eye appearance in order to differentiate eye anomalies from normal variability of eye structure. Normal external eye appearance is shown in Figure 1. (Additional images of the external eye can be found on the web, for example at: www.fotosearch.com/LIF118/sa702031/)

Figure 1. Anatomy of a Normal Human Eye



Humans typically have two eyes of equal size. The iris (colored part of the eye) surrounds a dark central pupil. This pupil normally fluctuates in size, becoming larger in dim light, and smaller in bright light. The sclera, or surface of the eyeball is normally white. The corners of the eye are called canthi. The inner canthus is closest to the nasal bridge, and the outer canthus is closest to the outer ear. The upper and lower eyelids each contain a complete row of eyelashes, and the space between the lids is called the palpebral fissure. The appearance of the palpebral fissures provides a starting place for examining the external eye.

Eye Orientation

Eye orientation is the relationship of the palpebral fissures to the remainder of the facial structures. A palpebral fissure is the physiologic name given to the separation between the upper and lower eyelids. In an adult, a palabral fissure measures about 10 mm vertically and 30 mm horizontally. Palabral fissures sometimes vary in orientation including horizontal size and vertical height. Three types of orientation can occur on the human face: horizontal, upslanting, and downslanting.