Glossary of Eye Terms

Accommodation

Accommodation is the mechanism that allows the eye to focus automatically on nearby objects, like the autofocus of a camera.

Amblyopia

Amblyopia, or “lazy eye”, is reduced vision in one eye (sometimes both) that cannot be fully corrected with glasses alone.

AMD

AMD — age-related macular degeneration — is a degenerative condition that affects the macula, the central zone of the retina responsible for the precise vision used to read, recognise a face, or drive. Read the article

Astigmatism

Having astigmatism means having an eye whose cornea or lens is not perfectly spherical, but slightly oval, like a rugby ball. Read the article

Cataract

A cataract is the progressive clouding of the natural lens, the leading operable cause of declining vision after 60 and one of the most refined procedures in ophthalmology. Read the article

Color blindness

Color blindness is an abnormality in the perception of colors, most often inherited, stable and harmless to the eye itself.

Cornea

The cornea is the transparent window at the front of the eye, the curved dome that lets light in and provides most of its focusing power.

Corneal topography

Corneal topography is a key examination in refractive ophthalmology. Read the article

Crystalline lens

The crystalline lens is the eye’s natural lens, a transparent structure sitting behind the iris that focuses the image so you can see clearly both up close and far away. Read the article

Dacryocystitis

Dacryocystitis is an infection of the tear sac, the small reservoir located at the inner corner of the eye, against the nose.

Diabetic retinopathy

Diabetic retinopathy is a retinal microangiopathy: chronic high blood sugar gradually damages the small blood vessels of the retina, the thin layer of nerve tissue lining the back of the eye that is responsible for vision. Read the article

Diopter

The diopter is the international unit that measures the power of a lens or a visual defect. Read the article

Diplopia

Diplopia is the perception of two images of a single object, in other words the experience of “seeing double”.

DMEK

DMEK (Descemet Membrane Endothelial Keratoplasty) is the reference technique for treating diseases of the corneal endothelium. Read the article

Dry eye

Dry eye is one of the most common complaints seen in consultation. Read the article

Epiretinal membrane

An epiretinal membrane is a thin fibrous layer that develops on the surface of the macula, causing progressive visual distortion. Read the article

Eye floaters

Floaters that have been present for a long time, few in number and stable, do not require any particular intervention: they often fade over time, as the brain learns to ignore them. Read the article

Farsightedness

Farsightedness (hyperopia) is a refractive error, just like nearsightedness or astigmatism.

Fovea

The fovea is the small depression at the centre of the macula, the area of the retina responsible for the finest central vision.

Glaucoma

Glaucoma is a chronic optic neuropathy that remains asymptomatic for a long time. Read the article

ICL

The phakic implant (ICL EVO Visian) is a precision surgery, particularly indicated when LASIK is not suitable (high myopia beyond -10 D, thin cornea, dry eye). Read the article

Intraocular lens

A trifocal multifocal implant is an intraocular lens with a diffractive profile that splits incoming light into three focal points: far, intermediate (around 60-80 cm) and near (40 cm). Read the article

Iris

The iris is the colored membrane of the eye, the disc located behind the cornea that gives the eyes their blue, green or brown hue. Read the article

Keratitis

Keratitis is inflammation of the cornea, the clear lens at the front of the eye. Read the article

Keratoconus

Keratoconus is a progressive deformation of the cornea that most often appears in adolescence or in young adults. Read the article

LASIK

LASIK (short for Laser-Assisted In situ Keratomileusis) is a laser refractive surgery technique. Read the article

Macular edema

Macular edema is a build-up of fluid in the macula, the central part of the retina responsible for fine, detailed vision.

Macular hole

A macular hole is a small opening that forms at the centre of the retina, in the area of sharp vision known as the macula.

Miosis

Mydriasis refers to an abnormally dilated pupil, miosis to an abnormally constricted one. Read the article

Monovision

Monovision may appeal to presbyopic people bothered by their dependence on reading glasses, whether they are otherwise short-sighted, long-sighted or emmetropic. Read the article

Mydriasis

Mydriasis refers to an abnormally dilated pupil, miosis to an abnormally constricted one. Read the article

Myopia

Myopia is a vision disorder caused by a mismatch between the optical power of the eye and its length. Read the article

Orthoptist

The orthoptist is a paramedical professional specialised in the screening, assessment and rehabilitation of disorders of vision and eye movement.

Phacoemulsification

Phacoemulsification is the reference technique for cataract surgery: it involves breaking up the clouded lens with ultrasound, then aspirating it through a micro-incision, before placing an intraocular implant in its place.

Phosphenes

Phosphenes are light sensations — flashes, flickers, sparks — perceived by the eye without any real light source causing them. Read the article

Pre-Operative Assessment

The pre-operative assessment is a mandatory step before any refractive surgery (LASIK, PRK, SMILE) or phakic implant. Read the article

PresbyLASIK

PresbyLASIK is an excimer laser procedure that reshapes the curvature profile of the cornea to enable functional vision at several distances. Read the article

Presbyopia

Presbyopia is a natural change in vision that affects nearly everyone after 45. Read the article

PRK

Trans-PRK (transepithelial PRK, 100% laser, no-touch) and conventional PRK are the reference surface laser techniques for thin corneas. Read the article

Pterygium

A pterygium is a conjunctival growth that progressively invades the cornea. Read the article

Pupil

The pupil is the black opening at the centre of the iris, the aperture through which light enters the inside of the eye.

Refractive surgery

Refractive surgery covers all the surgical techniques used to correct vision defects: myopia, hyperopia, astigmatism and presbyopia: in order to reduce or eliminate dependence on glasses and contact lenses. Read the article

Retina

The retina is the thin, light-sensitive membrane that lines the back of the eye, the equivalent of a camera’s sensor.

Retinal detachment

Retinal detachment is the separation of the neurosensory retina from the underlying pigment epithelium. Read the article

Scotoma

A scotoma is an area of the visual field where perception is reduced or absent.

Secondary cataract

The term “secondary cataract” is well established by usage, but it is misleading: it is not a recurrence of cataract. Read the article

SMILE

SMILE (Small Incision Lenticule Extraction) is a third-generation refractive surgery technique. Read the article

Solar retinopathy

Solar retinopathy is a photochemical burn of the photoreceptors at the centre of the retina, caused by looking directly at the Sun without a suitable filter. Read the article

Visual acuity

Visual acuity is the eye’s ability to distinguish fine detail and to separate two very close points. Read the article

Visual field test

The visual field test, also known as perimetry, maps the full extent of what you perceive around the point you are fixing on, without moving your eyes.

Vitrectomy

Vitrectomy is a vitreoretinal microsurgery procedure that involves removing the vitreous — the transparent gel that fills the back of the eye — to treat several retinal conditions. Read the article

Vitreous detachment

Posterior vitreous detachment (PVD) is a natural part of the eye’s ageing process: the gel that fills the globe separates from the retina.

Is a term missing or still unclear? Ask about it at your consultation. contact the practice