Standard Cataract Surgery (Phaco)

The Cause of Cataract

Many factors are thought to play a role in age-related cataract. As the lens ages, its weight and thickness increase and its nucleus becomes compressed and hardens. The lens proteins called “crystallins” undergo a chemical change, and as a result the lens becomes less transparent.

Symptoms of Cataract

• Reduced vision
• Glare and scattering of light around lights
• Myopia (with certain types of cataract, being able to read without reading glasses)
• Difficulty telling shades of colour apart
• Double vision

Diagnosis of Cataract

• Visual acuity is measured.
• The type of cataract is determined with an examination instrument called a biomicroscope (slit lamp).
• The pupils are dilated and the retina, the nerve layer of the eye, is examined.
• If the cataract is very dense, the retina cannot be seen; in that case a B-scan ultrasound examination shows whether there is an additional problem at the back of the eye.
• The cells of the cornea (the clear front layer of the eye) are counted. This count is called “specular microscopy”. It shows in advance whether there is a risk of permanent corneal swelling after cataract surgery.

Treatment of Cataract

There is no treatment for cataract with medication or eye drops. The only treatment is surgery. Today cataract surgery is performed with a technique called “phacoemulsification”, in which the cataractous lens is broken up with ultrasound energy and removed by suction.

How Cataract Surgery (Phacoemulsification) Is Performed

• The eye is numbed with anaesthetic drops. In some cases general anaesthesia is needed: in children, after eye injuries, and in conditions that prevent the patient from lying still on their back (for example dementia, extreme fear, panic attacks or intellectual disability).
• The eyelids are held open with an instrument called a “lid speculum”.
• A 3.2 mm incision is made in the eye with a “slit knife”.
• The eye is entered through this incision, and the capsule over the cataractous lens is opened in a round shape.
• Fluid is injected around the cataractous lens inside the capsule.
• The cataractous lens is broken up and aspirated with the tip of the phacoemulsification device.
• An artificial lens is placed inside the remaining lens capsule.
• An antibiotic–steroid injection and ointment are applied and the eye is bandaged.

Possible Complications of Phacoemulsification

• During the operation:
• A tear in the lens capsule
• Fragments of the lens, or the whole lens, dropping into the back of the eye
• After the operation:
• A serious eye infection called “endophthalmitis”
• Corneal oedema (fluid build-up and swelling)
• Displacement of the implanted lens
• Detachment of the nerve layer of the eye (retinal detachment)
• Oedema of the macula, the central part of the retina

Types of Artificial Lens Used in Cataract Surgery

Intraocular lenses are made of various materials such as polymethyl methacrylate, acrylic, silicone and collamer. What these materials have in common is that they are compatible with body tissues. Some intraocular lenses filter ultraviolet light and some are multifocal. With standard lenses, reading glasses are needed for near vision; with multifocal lenses, 90 out of 100 people no longer need reading glasses.

There are several types of intraocular lens:

• Lenses placed in front of the pupil (anterior chamber lenses)
• Lenses placed behind the pupil:
• Sutureless lenses (in-the-bag lenses, sulcus lenses)
• Sutured lenses (scleral-fixated lenses)

Intraocular lenses come in various diameters and powers. The diameter depends on which part of the eye the lens will be placed in. The power the lens should have is determined by measurements taken before surgery — the most important factor in whether distance glasses will be needed afterwards.

Intraocular lenses stay in the eye for life. The quality, design and material of the lens affect the quality of vision. The design of the lens edges is also related to “posterior capsule opacification” (the lens capsule losing its transparency), which develops after surgery; with some lenses this loss of transparency is less common. Manufacturing standards are controlled by the CE mark in Europe and by FDA approval in the United States, and lenses implanted in the eye must carry at least one of these approvals.

Care After Surgery

No hospital stay is needed after the operation. The eye is checked the next day. The prescribed eye drops must be used regularly; they are applied during waking hours by pulling the lower eyelid down.

First week: do not sleep on the operated eye. Keep water and soap out of the eye. Wash your hair with your head tilted back, as at a hairdresser. Do not use cream or make-up around the eye. Wear sunglasses outdoors, or your own glasses if you have them (with the lens on the operated side replaced by a plain one). Walking is fine; swimming, lifting weights and prostrating in prayer should be avoided.

From the second week: normal daily life can be resumed. However, the eyes should never be rubbed hard.

Glasses After Cataract Surgery

A glasses check is done one month after the operation. Thin glasses may or may not be needed for distance vision. For near vision (reading and so on), glasses are essential.

If multifocal artificial lenses are implanted, about 90% of patients can see both near and far without glasses.

Eye Check-ups After Cataract Surgery

Routine eye check-ups are done the day after the operation, after one month and after six months. At the six-month examination we check whether the capsule holding the artificial lens has lost its transparency — “posterior capsule opacification”. This can develop anywhere between three months and four years after the operation. When it does, the centre of the clouded capsule is opened with a YAG laser, removing the curtain effect in the central area. A YAG laser treatment for posterior capsule opacification is needed in 10–15% of people who have had cataract surgery.

It is important for anyone who has had cataract surgery to have an eye examination once a year for life.