Aqueous humor
Watery fluid which bathes and nourishes the front of the eye.

Bilateral retinoblastoma
Cancerous tumor(s) in the retina of both eyes.

CAT Scan
Test which uses x-rays to view the eyes and brain.

Choroid
A layer of blood vessels that feeds the retina.

Chromosome 13
The chromosome which has a missing piece that is responsible for the development of retinoblastoma.

Conjunctiva
Thin membrane which lines the outside of the eye.

Cornea
The clear outer part of the eye’s focusing system light entering the eye.

Cryotherapy
Freezing treatment for small retinoblastoma tumor(s).

Disc Diameter
Horizontal size of the optic nerve head approximately 1-1.5 mm used as a reference point to measure tumors.

Enucleation
Surgical removal of the eye.

Equator
A circular reference zone approximately half way between the back of the eye and the front of the eye.

External Beam Radiation
Treatment which uses machines to give radiation to treat the tumors.

Eyelid
The skin-covered structure that protects the front of the eye.

Fovea
The center of the macula that gives the sharpest vision.

Fundus Drawing
Map of the eye with tumor sketches drawn by the ophthalmologist.

Indirect Ophthalmoscope
Instrument used to view the retina.

Iris
The colored part of the eye.

Lamina Cribrosa
The zone in the optic nerve which represents the anatomical end of the eye.

Laser
Light therapy used to treat small retinoblastoma tumors(s).

Lens
The clear part of the eye behind the iris that helps to focus light on the retina.

Leukocoria
Which pupillary reflex; cats' eye reflex; the most common presenting sign of retinoblastoma.

Macula
The small sensitive area of retina that gives central vision.

Metastasis
Spread of a cancer to other parts of the body.

Optic Nerve
The bundle of over one million nerve fibers that carries visual messages from the retina to the brain.

Ora Serrata
Portion of the retina near the front part of the eye.

Pediatric Oncologist
Physician who specializes in cancer of children.

Prognosis
The overall outlook of treatment.

Pupil
The opening at the center of the iris that controls the amount of light.

Radioactive I-125 Plaque
A disc of radiation that is sewn to the eye to treat the retinoblastoma tumor(s).

Retina
The light-sensitive tissue lining the back of the eyeball.

Retinoblastoma
A cancerous tumor of the retina of the eye.

Sclera
The tough, white outer coat of the eye.

Strabismus
Crossed eyes; second most common presenting sign of retinoblastoma.

Ultrasound
Test which uses sound waves to view the eye and tumor(s).

Unilateral retinoblastoma
Cancerous tumor(s) in the retina of one eye.

Vitreous Humor
The clear gel filling the inside of the eye.

Vitreous Seeding
Small balls of retinoblastoma that break off and extend into the vitreous.