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F (Field Analyser to Fovea)

Field Analyser

Thursday, January 14th, 2010

Instrument which requires the patient to inform the operative of their ability or not to see numerous images in different positions on a screen to assess the patient’s field of view. Used for the early diagnosis and treatment of the diseases that cause field loss such as glaucoma.

Flashing Lights

Thursday, January 14th, 2010

Seen even when the eyes are closed. Often quite normal in an aging eye as the vitreous pulls away from the retina. Can last for several months but should be investigated in case the retina is torn.


Thursday, January 14th, 2010

Floating particles within the vitreous often appearing like a moving thread. A sudden appearance or increase should be investigated.

Focal Length

Thursday, January 14th, 2010

The distance from the refracting (lens) or the reflecting (mirror) surface to the point of focus.


Thursday, January 14th, 2010

The small area of the retina that provides the sharpest vision by allowing the light to fall directly onto the cones without having to pass through any retinal layers.