Glossary

SCC - Squamous Cell Carcinoma - Cancer of Squamous epithelial cells found in the outer skin and some internal linings. It is the second commonest form of skin cancer and occurs generally late-middle age. It is mainly found on areas exposed to sunlight. It can spread locally at first but then to other sites (metastasis). Treatment is by surgical excision or radiotherapy.

Sclera - The protective, white fibrous outer layer of the eyeball containing collagen and elastic fibres. It is continuous with the cornea in front and with the sheath covering the optic nerve behind and helps maintain the shape of the eyeball giving resistance to internal and external forces.

Secondary Cataract - An opacity that develops in the crystalline lens not due to the normal ageing process but due to a secondary event like disease (diabetes), eye injuries, drugs (steroids) and chronic eye inflammation (Uveitis).

Slit Lamp - An instrument using a narrow slit of light and a microscope to examine in detail the outer and inner parts of the eye, one layer at a time.

Sphere - The spherical component of corrective lenses prescribed by an Optometrist or Ophthalmologist that gives the same power over the entire lens. It is measured in dioptres and convergent powers are positive and converge light to correct long-sightedness. Divergent powers are negative to correct short-sightedness.

Starbursts - A form of glare seen by the eye in low levels of light when observing a light source. It has a shape or design with emanating streaks of light similar to the light produced by an exploding star and is often reported by individuals who have uncorrected refractive error or those who have had previous corneal surgery or injury.

Strabismus - Squint  An abnormal alignment of the eyes due to weakness in one or more of the extra-ocular muscles that control eye movement. The misalignment is most commonly horizontal but can also be vertical or at an angle (oblique) and can cause double vision due to the loss of binocular vision. The condition can be congenital or acquired through injury.

Stroma - Transparent fibrous tissue that makes up the main central body of the cornea at the front of the eye.