Understanding your eyes

An interactive 3D model of the eye, and plain-English guides to the conditions Mr Than treats, what treatment involves and what recovery is like.

Interactive 3D eye model

See where eye conditions happen

The 3D eye model is provided to help patients better understand the anatomy of the eye and the location of different eye conditions. You can rotate it, take it apart layer by layer and cut through it, then switch on a condition to see exactly where it affects the eye, from cataract at the front to macular holes and retinal detachment at the back.

Separate the cornea, lens, vitreous and retina
Cut a cross-section from the side, top or front
Show cataract, macular hole, epiretinal membrane, retinal detachment, vitreous haemorrhage and diabetic traction
Watch animations of cataract surgery with a lens implant, posterior vitreous detachment and vitreomacular traction

Open the 3D eye model →

Patient guides

Conditions explained

Select a condition to read about symptoms, treatment and recovery.

When to seek help the same dayA sudden shower of new floaters, flashing lights, or a dark shadow or curtain spreading across your vision can mean a retinal tear or detachment. Contact your local eye casualty, an optometrist or NHS 111 the same day. Do not wait for a routine appointment.

A healthy macula in cross-section, drawn as it appears on an OCT scan. The dip in the centre is the fovea, which gives you your sharpest vision.

Surgical

Retinal detachment

The retina peels away from the back wall of the eye

What it is: The retina is the light-sensitive layer lining the inside of the eye. In a detachment, fluid passes through a tear and lifts the retina away from the wall of the eye, so it stops working. Most detachments start with a tear caused by the vitreous gel pulling away from the retina with age.
Symptoms: New floaters, flashing lights, and a shadow that spreads from the edge of your vision. If the centre of the retina (the macula) detaches, central vision becomes blurred.
Treatment: Surgery is almost always needed. Options are a vitrectomy, where the gel is removed and the retina is flattened and held in place with a gas bubble or silicone oil; a scleral buckle, a band stitched to the outside of the eye; or, for selected detachments, pneumatic retinopexy, a gas injection in clinic. Most retinas are successfully reattached with one operation.
Recovery: You may need to hold your head in a set position for some days. You must not fly or travel to high altitude while gas is in the eye, and you must tell any anaesthetist, because nitrous oxide anaesthetic gas can expand the bubble dangerously. Vision recovers over weeks to months.

Surgical

Macular hole

A small full-thickness gap at the centre of the retina

What it is: A small hole forms in the macula, the part of the retina used for reading and recognising faces. It is usually caused by the vitreous gel pulling on the macula as it separates with age.
Symptoms: Blurred or distorted central vision, with straight lines looking bent or a small gap in the middle of what you look at. Side vision is not affected.
Treatment: A vitrectomy. The vitreous gel is removed, a very thin layer is peeled from the surface of the retina (the internal limiting membrane), and the eye is filled with a gas bubble that supports the hole while it closes. Most holes close after surgery.
Recovery: You may be asked to keep your face pointing down for a few days. Vision is very blurred while the gas is present and improves as it absorbs over a few weeks. Surgery speeds up cataract formation, so many patients need cataract surgery later.

Surgical

Epiretinal membrane

A thin layer of scar tissue on the surface of the macula

What it is: A transparent sheet of tissue grows on the surface of the macula and contracts, wrinkling the retina beneath it. It is common with age and can follow other eye conditions or surgery.
Symptoms: Many people have no symptoms. Others notice distortion, blurring, or objects appearing a different size in each eye.
Treatment: If the membrane is not bothering you, monitoring is reasonable. If distortion affects daily life, a vitrectomy with membrane peeling removes the scar tissue.
Recovery: Distortion usually improves gradually over several months, though some may remain. Most patients do not need strict head positioning after this operation.

Surgical

Diabetic vitrectomy

Surgery for bleeding or scar tissue from diabetic eye disease

What it is: In advanced (proliferative) diabetic retinopathy, abnormal new blood vessels grow on the retina. They can bleed into the vitreous gel, or form fibrous membranes that contract and pull the retina off the wall of the eye (tractional retinal detachment).
Treatment: A vitrectomy clears the blood. Membranes are carefully separated from the retina, a technique called delamination, to release the traction. Laser is applied during the operation to calm the disease, and gas or silicone oil may be used to support the retina.
Recovery: Recovery depends on how much the retina was affected before surgery. Good control of blood sugar, blood pressure and cholesterol remains essential to protect both eyes.

Surgical

Complex cataract

Cataract surgery in eyes that need extra planning

What it is: A cataract is clouding of the natural lens. Surgery is more complex when the pupil does not widen well, the lens is very dense, the fibres holding the lens are weak, or the eye has had previous surgery such as a vitrectomy.
Treatment: Careful planning before surgery, with devices to widen the pupil or support the lens capsule where needed. In eyes that also need retinal surgery, cataract and vitrectomy can sometimes be done in a single operation.
Recovery: Most patients go home the same day and use eye drops for several weeks. Your vision may take a little longer to settle than after routine cataract surgery.

Surgical

Secondary lens implants

Replacing or fixing a lens that is missing or has moved

What it is: Sometimes a lens implant cannot be placed in the usual position during cataract surgery, or an existing implant dislocates years later. Without a properly positioned lens, vision is very blurred.
Treatment: A secondary lens can be fixed to the wall of the eye (scleral fixation), clipped to the iris, or placed in front of the iris, depending on the eye. A dislocated lens can often be repositioned or exchanged. This is often combined with a vitrectomy.
Recovery: Similar to cataract surgery, with drops for several weeks. You may still need glasses for some distances.

Medical retina

Age-related macular degeneration

The most common cause of central vision loss over 50

What it is: AMD affects the macula. In dry AMD, the cells of the macula thin slowly over years. In wet AMD, abnormal blood vessels grow under the retina and leak, which can damage vision quickly.
Symptoms: Distorted straight lines, a blurred or dark patch in the centre of vision, and difficulty reading. Sudden distortion needs prompt assessment.
Treatment: Wet AMD is treated with regular anti-VEGF injections into the eye, which stop the vessels leaking. The injection is done under local anaesthetic drops and takes a few minutes. Dry AMD has no routine NHS treatment yet, but stopping smoking and a healthy diet help, and low-vision support is available.
Monitoring: Check each eye on its own regularly with an Amsler grid or a window frame, and report any new distortion.

Medical retina

Diabetic retinopathy and macular oedema

Damage to the retinal blood vessels from diabetes

What it is: High blood sugar damages the small blood vessels of the retina. They may leak fluid into the macula (diabetic macular oedema), or close off and trigger abnormal new vessel growth (proliferative retinopathy).
Symptoms: Early disease has no symptoms, which is why yearly diabetic eye screening matters. Later, vision may blur or sudden floaters may appear from bleeding.
Treatment: Macular oedema is usually treated with anti-VEGF or steroid injections. Proliferative retinopathy is treated with laser (panretinal photocoagulation), injections, or vitrectomy surgery for bleeding or traction.
What you can do: Attend every screening appointment and keep blood sugar, blood pressure and cholesterol well controlled.

Medical retina

Retinal vein occlusion

A blockage in one of the veins draining the retina

What it is: A vein carrying blood out of the retina becomes blocked, causing bleeding and swelling. It can affect the main vein (central) or one of its branches. High blood pressure, diabetes, high cholesterol and glaucoma increase the risk.
Symptoms: Sudden painless blurring of all or part of the vision in one eye.
Treatment: Swelling at the macula is treated with anti-VEGF injections or a slow-release steroid implant. Laser may be used if abnormal vessels develop. Your GP should also check your blood pressure, blood sugar and cholesterol.

These guides are general information and do not replace advice from your own doctor or optometrist about your eyes.

Seeing Mr Than at Milton Keynes

NHS patients are seen in the Department of Ophthalmology, Milton Keynes University Hospital Community Diagnostic Centre, Lloyds Court, Milton Keynes, on referral from a GP or optometrist.

Referrals and appointments →