About the Profession | Department of Ophthalmology | School of Medicine

Sample diagnostic image of the back of a left eye

Ophthalmic technicians and technologists assist in the workup and assessment of patients coming to see an eye doctor. They are responsible for administering the various diagnostic tests which the physician will need in order to make a diagnosis and treat the patient’s condition.

Within this role, technicians and technologists are involved in the following sorts of testing:

Visual acuity testing

This is performed to figure out how well a patient is able to see in a standardised fashion. The test involves determining the smallest letters that a patient can read on a chart. It ultimately measures the integrity of a patient’s central vision, allowing us to assess how vision is changing (whether it is improving, or deteriorating).

Tonometry

This is a test used to figure out the pressure within the eye. The inside of the eye is filled with fluid—a clear gel, called the vitreous, and a watery fluid called the aqueous humour. The latter is what contributes to the intraocular pressure, as the variation in flow and drain of aqueous humour can vary, or be impacted by disease.

Tonometry is performed to determine the intraocular pressure of the eye—a high pressure inside the eye can lead to damage to the structure of the eye, and can point to vision-threatening disease; a low pressure can result in blurred vision, but left unchecked can cause greater issues in vision.

Results are recorded in millimeters of mercury (mmHg).

Ultrasound

A-scan Biometry is used routinely to measure the axial length of an eye. This is most commonly performed prior to cataract surgery.
B-scan ultrasound is a two-dimensional cross-sectional scan of the posterior eye and orbit. It is used to assess the pathology and structural integrity of the globe.
Standardized A-scan is a standardized instrument used to measure the differentiation of tissues within the eye and the orbit.

Ultrasound Biomicroscopy (UBM) is used to image the anatomy of the anterior segment of the eye, as well as associated pathologies.

Visual Field Testing

an examination used to detect a dysfunction within a patient’s central or peripheral visual field. Testing methods range from automated to manual, and can be static or kinetic in nature.

Ophthalmic Photography

a specialized form of medical imaging used to capture disorders of the eye. The broad scope includes fundus photography, intravenous fluorescein angiography (IVFA), indocyanine green angiography (ICG) and slitlamp photography. These imaging techniques allow us to document both the anterior and posterior segments of the eye.

Ocular Coherence Tomography

a non-invasive imaging technique that uses light waves to capture cross-section pictures of the retina. Through visualizing the retina’s distinctive layers, ophthalmologists can map and measure thickness thereby aiding with diagnosis and providing guidance for treatment.

Ocular Motility

The study and assessment of the extraocular muscles and their impact on eye movement. Various tests are used to observe and assess impaired eye movements and misalignment.