Glossary

At AVC, we understand that the technical jargon surrounding eye treatments and procedures can be daunting. This is why we’ve compiled a handy Glossary of all of the terms and phrases that’ll help make things clearer.

ABLATION

Surgical excision of the cornea using a laser during the treatment. Corneal tissue is evaporated by the cold energy of the laser.

ABERRATIONS

Imperfections in the optical system of the eye that can affect the quality of the vision. Measured by Wavefront technology.

ACCOMMODATION

Increase in optical power by the eye in order to maintain a clear image (focus) as objects are moved closer. Occurs through a process of ciliary muscle contraction and zonular relaxation that causes the elastic-like lens to ’round up’ and increase its optical power. Natural loss of accommodation with age is called presbyopia.

AMBLYOPIA

A condition in which a person’s vision does not develop properly in early childhood because the eye and the brain are not working together correctly. Amblyopia, which usually affects only one eye, is also known as ‘lazy eye.’ A person with amblyopia experiences blurred vision in the affected eye.  Early treatment is necessary otherwise this condition may lead to permanent vision loss. Treatment options include vision therapy exercises, prescription eyeglasses, or surgery. People with amblyopia may need to wear an eye patch over their stronger eye in order to force the affected eye to function as it should.

ANTIBIOTICS

These ointments or drops are administered regularly for the first few days / weeks after treatment. Oftaquix is commonly used by AVC.

ASTIGMATISM

Common vision condition caused by an irregularly curved cornea or crystalline lens. People with astigmatism may experience blurred vision, eyestrain, or headaches. Astigmatism can be corrected with eyeglasses or contact lenses. Laser eye correction can treat up to 6.00 Dioptres of astigmatism.

BANDAGE CONTACT LENS

This is a contact lens which the surgeon inserts in the eye directly after treatment. The lens protects the eye and reduces post-treatment discomfort. The lens is removed 24 / 48 hours after having the Lasik treatment and 4 / 5 days after Lasek.

BILATERAL

Referring to both eyes. Laser eye surgery is often bilateral.

BLEPHARITIS

Inflammation of the eyelids, usually with redness, swelling, and itching. This needs to be controlled before the eye can be treated with any correction or treatment.

BUTTONHOLE FLAP

A complication where the flap that is created has a central hole. Treatment is abandoned and the flap is put back to heal. The cornea is given time to heal (normally 2 months) and treatment can be re-done.

CATARACT

A Cataract is a condition in which the crystalline lens of the eye, which is normally clear, becomes cloudy or opaque. Cataracts generally form slowly and without pain. They can affect one or both eyes. Over time, a cataract may interfere with vision, causing images to appear blurred or fuzzy and colours to seem faded. Most Cataracts are related to aging. In fact, Cataracts affect more than 50 per cent of all adults by the age of 80, and are the primary cause of vision loss in people 55 and older. People in the early stages of this condition may benefit from new eyeglasses, bright lighting, anti-glare sunglasses, or magnifying lenses. Cataract Surgery, which is common, involves removal of the cloudy lens and replacement with an artificial lens.

CATARACT EXTRACTION

Removal of the cloudy crystalline lens from the eye. Surgical removal of cataracts and replacement with an artificial lens (called an intraocular lens) is the most successful surgical procedure in the country. This is performed on an out-patient basis under local anesthesia.

CONDUCTIVE KERATOPLASTY

CK Treatment is designed to strengthen your near vision using the controlled release of radio frequency energy; this procedure does not require a laser or any cutting, and is therefore a minimally invasive, safe and convenient alternative to reading glasses.

COMPLICATIONS

Like any elective surgery, Laser eye surgery is not 100 per cent risk free. During and after treatment patients may feel uncomfortable, experience tenderness, grittiness, glare around lights at night (halos), droopy eye lids, slight double vision or loss of best visual sharpness. These effects reduce gradually and rarely persist in the long term. The quality and experience of the surgeons at AVC mean that the clinic has a very low complication rate.

CONJUNCTIVITIS

Conjunctivitis is redness and soreness (inflammation) of the clear covering (the conjunctiva) which coats the white of the eye and lines the inside of the eye lids. This comes on relatively quickly and lasts for a fairly short time. Conjunctivitis may clear on its own, but often needs treatment from your doctor. This condition needs to have improved before treatment.

CONTRAST SENSITIVITY

Contrast sensitivity is the ability to see differences in contrast between objects or parts of objects. Reduced contrast sensitivity is a possible side effect of laser vision correction and is particularly troublesome in poor illumination. Wavefront technology can help reduce the drop in contrast sensitivity and sometimes can improve it.

CORNEA

The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber, providing most of an eye’s optical power. Because there are no blood vessels in the cornea, it is normally clear and has a shiny surface.

CRYSTALLINE LENS

The lens or crystalline lens is a transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to focus on the retina. Its function is thus similar to a man-made spectacle lens.

DIABETIC

Diabetic retinopathy is the most common diabetic eye disease and a leading cause of blindness in adults. It is caused by changes in the blood vessels of the retina. The longer someone has had diabetes, the greater the person’s likelihood of developing diabetic retinopathy. Changes in the tiny blood vessels of the retina can lead to vision loss. People with diabetes should have routine eye examinations so that diabetes-related problems can be diagnosed and treated as soon as possible. Maintaining strict control of blood sugar levels helps to prevent diabetic retinopathy. Surgical and laser treatments can help many people affected with this condition but this is a different type of treatment than laser eye correction.

DOMINANT EYE

Usually the eye used to focus a camera or fire a gun. This eye would usually be treated second if the patient is only having one eye treated at a time. Most of the time patients now have both eyes treated at the same sitting.

DRY EYE SYNDROME

Persistent dryness of the eyes resulting from too little production of tears or too rapid evaporation of tears. People with dry eye syndrome may experience such symptoms as itching, burning, or stinging eyes. Some people feel as though something is caught in their eye, causing an irritation. Dry eye syndrome has many causes. An Optician may recommend the application of special eye drop called artificial tears to moisten the eyes. There is also now medication to treat moderate to severe dry eye. Laser Eye Correction is not suitable for patients with severe dry eye.

EMMETROPIA

Emmetropia is the state of an eye that requires no refractive correction.

EYE TRACKER

At AVC we use the sophisticated Multi-dimensional Eyetracking Technology. This detects the positional changes of the eyes during the procedure, ensuring the patient’s safety is maintained throughout. Our state of the art Laser, the Bausch and Lomb z100 and the Eyetracking Technology enables us to deliver the highest quality and most accurate treatment available today.

EXCIMER LASER

A form of ultraviolet chemical laser which is commonly used in eye surgery and semiconductor manufacturing. They remove tissue accurately without increasing the temperature of the tissue. AVC uses the latest Bausch and Lomb z100 Technolas excimer laser.

FLOATERS

Specks or strands that seem to float across the field of vision. Floaters and spots are actually shadows on the retina cast by tiny bits of gel or cells inside the clear fluid that fills the eye. Floaters and spots usually are normal and harmless. However, in some cases they may warn of serious conditions such as retinal detachment, diabetic retinopathy, or infection. Someone who experiences a sudden decline in vision accompanied by flashes and floaters or a sudden increase in the number of floaters should consult an optician or ophthalmologist urgently. Only in very severe cases would they affect laser eye surgery.

GAS PERMEABLE CONTACT LENSES

A rigid type of contact lens that allows oxygen to permeate through, enabling the cornea to breathe. Gas permeable lenses (also known as RGP) need to be removed about one month prior to the consultation and treatment as they can warp the corneal shape.

GLARE

Star burst and flaring effect when looking at bright lights, particularly noticeable at night with car headlights. Can be a symptom of halos and haze and is the most common side effect of laser treatment. Wavefront technology can drastically reduce the incidence of Halo and glare.

GLAUCOMA

Disease in which the pressure of the fluid inside the eye is too high, resulting in a loss of peripheral vision. If the condition is not diagnosed and treated, the increased pressure can damage the optic nerve and eventually lead to total blindness. Vision lost as a result of such damage cannot be restored. A person who has glaucoma may not realise it at first, because the disease often progresses with no symptoms or warning signs. Early detection through regular eye examination and prompt treatment is essential to prevent vision loss. Daily medication (usually eye drops), surgery, or a combination of both enables most people to control their intraocular pressure and retain their vision. Glaucoma is a contra indication for laser correction but it depends on how it is controlled.

HALOS

Halos used to be experienced by patients with large pupils as the treated area of the cornea was smaller than pupil size. Wavefront technology can treat a larger optical zone and can now treat pupils up to 8.5mm.

HYPERMETROPIA (LONG-SIGHT)

This common vision problem occurs when light rays entering the eye focus further than the retina, not directly on it. Hyperopia may cause eyestrain or headaches, especially with reading. Eyeglasses or contact lenses can correct hyperopia. For people who do not want to wear glasses or contact lenses, laser vision correction is sometimes possible.

INCOMPLETE FLAP

If there has been a malfunction of the microkeratome, the flap creation process may have been aborted prematurely, resulting in an incomplete flap. In this instance the laser treatment is abandoned and the flap is replaced and left for three months to heal before laser treatment can be given again.

IRIS RECOGNITION

Like your fingerprints, no two irises are the same and this can be used to provide a unique identification. The Zyoptix z100 system can scan your irises during the Zywave measurement and maps the entire iris, generating a unique digital Zy-ID for each eye.

KERATOCONUS

Keratoconus is a rare condition, often inherited, in which the cornea becomes progressively thinner and gradually bulges outward, causing blurred or distorted vision. The condition usually affects both eyes.

LASER

Acronym: Light Amplification by Stimulated Emission of Radiation. High energy light source that uses light emitted by the natural vibrations of atoms (of a gas or solid material) to cut, burn or dissolve tissues for various clinical purposes: in the retina, to treat diabetic retinopathy and macular degeneration, to destroy leaking and new blood vessels (neovascularization); on the iris or trabecular meshwork, to decrease pressure in glaucoma; after extracapsular cataract extraction, to open the posterior lens capsule.

LASEK PROCEDURE

Lasek is an abbreviation of Laser Epithelial Keratomilieusis and is a combination of the positive features of PRK (Photorefractive Keratectomy) and Lasik (Laser Assisted Subepithelial Keratectomy). Lasek is also sometimes known as ‘Epi-Flap’. The Lasek procedure involves the epithelium or outer layer of the cornea being placed aside with the help of a dilute alcohol solution. Once the epithelial layer has been displaced, an excimer laser is then used to reshape the cornea, as in Lasik.

LASIK PROCEDURE

Lasik is a highly successful and popular procedure for vision correction that has been available for over 15 years. The process creates a thin-hinged flap on the cornea (front of the eye) with a precise surgical instrument called a microkeratome.

LAZY EYE

This eye condition is noted by the reduced vision that is not correctable by glasses or contact lenses and is not due to any eye disease. This is usually a contra-indication to laser treatment. Mild forms can sometimes be helped by laser treatment but if the vision is poor in the lazy eye then laser correction cannot help. Also see AMBLYOPIA.

MACULAR DEGENERATION

Disease that causes dysfunction of the macula, the area in the middle of the retina that makes possible the sharp central vision needed for such everyday activities as reading, driving, and recognising faces and colours. The condition is commonly known as age-related macular degeneration (ARMD), and is the leading cause of visual impairment among older people. Macular degeneration causes blurred, distorted, or dim vision or a blind spot in the center of the visual field. Peripheral vision is generally not affected. There is no cure for macular degeneration, but drug therapy, laser surgery, or other medical treatment may in some cases be able to slow the disease’s progression or prevent further vision loss.

MICROKERATOME

See XP MICROKERATOME.

MONOVISION

Vision with the use of only eye for distance and the other eye for clear reading vision. Some older patients who have one eye treated may find monovision a distinct advantage in that they do not need glasses at all. Conductive Keratoplasty is an improved form of monovision which creates blended vision in the non-dominant eye so the distance vision is less affected than is monovision.

MYOPIA (Short sight)

This condition occurs when light rays entering the eye focus in front of the retina, not directly on it. People with myopia are usually able to see close objects well, but objects in the distance appear blurred. People with this condition may squint to see distant objects and experience eyestrain or, sometimes, headaches. Spectacles or contact lenses can correct myopia. Surgery is another alternative.

NEOVASCULARISATION

Abnormal formation of new blood vessels, usually in or under the retina or on the iris surface. May develop in diabetic retinopathy, blockage of the central retinal vein, or macular degeneration.

NOMOGRAM

The surgeon’s adjustment to the laser’s computer calculation to further refine his results taking into account extra information which the computer cannot measure.

NYSTAGMUS

Condition that involves involuntary, rapid, repetitive movements of one or both eyes from side to side, up and down, or in a circular motion. Nystagmus may be present at birth or, less commonly, may result from disease or injury. In some cases, the condition can reduce or interfere with vision. Very mild levels of nystagmus may be possible to treat but a full assessment by Mr. C.T. Pillai is imperative.

OCULAR

Of or relating to the eye.

OPHTHALMOLOGIST

A doctor who specialises in the eye and its diseases. AVC’s Medical Director Mr. C.T. Pillai is fully qualified with 19 years of ophthalmic experience. As well as being a fellow of the Royal College of Surgeons (FRCS) and Royal College of Ophthalmologists (FRCOphth), Mr. Pillai is currently Chairman of the UK’s Refractive Surgeons Association (RSA).

OPTICIAN NETWORK

AVC has established a network of clinical partners, (all of whom are experienced and accredited Optometrists) in the UK and Ireland to act as a referral base for initial consultation and aftercare. Our partners are well-trained, experienced professionals in refractive surgery. They are able to carry out both initial assessments and post-operative checks. All of AVC’s partners receive continued training and support from the company to ensure that the best possible care is received by all patients, who live outside the London area and who require local initial assessments and aftercare.

ORBSCAN

The Orbscan IIz topographer analyses the physical shape and contours of your cornea and allows our surgeon to decide if it has a suitable shape and is healthy and thick enough for treatment. It is the only topographer currently available that measures the shape of both the front and back surface of the entire cornea and can therefore provide a complete picture of the dimensions of the cornea.

PREGNANCY

AVC will not treat a woman who is pregnant or breast-feeding. They are advised to wait until three months afterwards. The eyes can change during and after pregnancy meaning that the vision can alter slightly.

PRESBYOPIA

The eye’s gradually decreasing ability to focus on nearby objects. Presbyopia is a normal part of aging and affects virtually everyone, usually becoming noticeable after age 40. People with presbyopia typically hold reading materials at arm’s length in order to bring the words into focus. They may experience headaches or eyestrain while reading, viewing a computer screen, or doing close work. Presbyopia has been traditionally treated with reading glasses, bifocals, or contact lenses. But now there is Conductive Keratoplasty, a minimally invasive procedure developed specifically for presbyopic patients who need near vision improvement.

PTERYGIUM

A pterygium is a raised, triangular or wedge-shaped growth of conjunctival tissue which grows over the surface of the cornea (the transparent dome at the front of the eye). It usually occurs on the nasal side of the cornea. In the early stages only small grey opacities at the junction of the cornea and the white of the eye can be seen. The conjunctiva can then overgrow these opacities and encroach on to the cornea in a triangular fashion. Laser eye surgery is possible as long as the pterygium does not invade onto the cornea.

PUPIL

Variable-sized black circular opening in the center of the iris that regulates the amount of light that enters the eye.

RETINA

Light sensitive nerve tissue in the eye that converts images from the eye’s optical system into electrical impulses that are sent along the optic nerve to the brain. Forms a thin membranous lining of the rear two-thirds of the globe.

READING GLASSES

Needed by virtually everyone after they reach their mid-forties. This is because the muscles in the eye slowly become stiffer and is no longer able to focus clearly on objects very close up. The need is medically known as PRESBYOPIA. Conductive Keratoplasty is a treatment we offer at AVC to remove the need for reading glasses.

STRABISMUS or SQUINT

Condition in which the eyes are not both directed toward the same point simultaneously. Strabismus occurs when eye muscles are not working together properly. It is most commonly an inherited condition, but may also be caused by disease or injury. If diagnosed early, strabismus can usually be corrected. The condition may be treated with corrective eyeglasses, eye-muscle exercises, surgery, or a combination of these approaches. Young children with this condition may need to wear an eye patch over their stronger eye to force their weaker eye to function correctly. Children whose strabismus is not corrected may develop amblyopia. It is usually a contra-indication to treatment patients who are happy with their sight with contact lenses can be considered for laser treatment.

STYE

Acute pustular infection of the oil glands of Zeis, located in an eyelash follicle at the eyelid margin. This appears as a small lump on the inner or outer surface of the eyelid. Patients are advised to wait until the inflammation has cleared before undergoing laser eye correction.

TISSUE SPARING TREATMENT

Laser eye treatments involve the removal of a small quantity of tissue from the front surface of the eye (the cornea). This will slightly alter the curvature of the cornea, and thereby improving your vision. The higher the prescription then the more the tissue needs to be removed. Tissue-sparing can remove up to 25% less tissue than standard treatment. Instead of merely treating the prescription the laser is guided in its treatment by the actual structure of the eye using the information collated from the scans taken at the initial consultation. This means that no two treatments are the same as each one takes into account the individual differences between each person’s eyes.

20/20 VISION

Normal visual acuity. Upper number is the standard distance (20 feet) between an eye being tested and the eye chart; lower number indicates that a tested eye can see the same small standard-sized letters or symbols as a normal eye at 20 feet. This is the American measurement; the UK version is 6/6.

VISUAL ACUITY

The measurement of visual clarity. Best corrected visual acuity (VA) is the measurement of the best vision achieved with glasses or contact lenses. Uncorrected VA is the sharpness of vision without spectacles and contact lenses.

XP MICROKERATOME

The successor to the Hansatome which many clinics still use, the XP Microkeratome is used to create the flap during the LASIK procedure.

ZERNIKE POLYNOMIAL

The Zernike polynomials are a set of orthogonal polynomials that arise in the expansion of a Wavefront function for optical systems with circular pupils. These are a mathematical way of measuring the aberrations (imperfections) in the eye which are corrected by the Wavefront technology.

ZYOPTIX

The very latest development in laser eye treatment from Bausch and Lomb is a system called Zyoptix. This is an advanced procedure that delivers a treatment unique to every individual. The laser has many safety features that help to optimise the success of your treatment. It has a unique integrated diagnostic system; one set of data thoroughly evaluates the structure of your cornea to make sure you are a suitable candidate. The second measures your eyes’ anatomy to determine its unique optical characteristics using advanced Wavefront technology. This process enables the surgeon to plan a personalised laser vision correction procedure completely individualised to you.

Contact us:

Looking for a term or word we haven’t covered? Ask us about it directly by calling our team on 020 7935 7497 or sending us an email at enquiries@advancedvisioncare.co.uk