Glossary

OCT - Optical Coherence Tomography - A diagnostic imaging machine particularly suited for detailed analysis of small tissue layers. The principles of OCT are similar to those of ultrasound but using infrared light instead of sound waves. Optical tomography creates a digital model by reconstructing images made from light transmitted and scattered through an object. It is especially useful for scanning the retina and to track anatomical changes and disease processes.

Ocular Hypertension - Intra-ocular pressure in the eye that is higher than normal in the absence of optic nerve damage or visual field loss. The general consensus for normal pressure of the eye lies between 10 and 21mmHg (millimetres of mercury). An elevated eye pressure is a risk factor for glaucoma damage.

Oculyzer - A diagnostic imaging system used to measure and analyse information from the anterior segment of the eye, from the front of the cornea to the back of the lens. The measured data are used in refractive and intra-ocular surgery and produce a three dimensional model of the anterior eye chamber. This information is used for customising individual eye treatments using the excimer laser or pre-operative planning for cataract surgery.

Ocuscan - Diagnostic equipment used for high quality eye measurements using ultrasound such as eye length, for calculation of intra-ocular lens power (A-scan Biometry) and corneal thickness (Pachymetry).

Open Angle Glaucoma - The most common type of glaucoma where there is a slow rise in eye pressure and progressive optic nerve damage but the drainage area is free from any blockage (open angle). Often there is an overproduction of aqueous fluid. In general the condition is painless and there are no symptoms but undetected the optic nerve will continue to be damaged and permanently affect the vision, even causing blindness. Treatment is usually by instilling eye drops to reduce the eye pressure.

Ophthalmologist - A medical doctor (Physician) specialising in the medical, surgical or refractive treatment of eye disorders and diseases.

Ophthalmoscope - An instrument used for examining the interior structures of the eye, especially the retina. Essentially it consists of a mirror that reflects light into the eye, a set of focusing lenses and a central hole through which the eye is examined.

Optic Disc - The end of the optic nerve in the eye. It is usually circular and contains blood vessels from the optic nerve. It is insensitive to light and so creates a natural blind spot.

Optic Nerve - Sensory nerve in the eye that carries information relating to vision from the retina to the brain.

Optometrist - A professionally trained person, who is licensed to examine the eyes for visual problems, detect eye disease, prescribe corrective spectacles or contact lenses or provide other treatment options.

Orbitofacial Surgery - Specialist plastic surgery in the eyelid and orbital region of the face.