There are an estimated 160 million people worldwide who are visually impaired and cataract accounts for almost 50% of this visual impairment. It is the leading cause of blindness and in the local context, a national eye survey found that cataract accounts for 39% of blindness.
The eye functions like a camera i.e. there is a lens which focuses light onto the ‘film’ (retina). In the eye, images from the retina are processed into electrical signals and sent to our brain which then interprets these signals as images.
With age, the lens becomes cloudy, hence, forming a cataract.
Causes of Cataract
The most common cause for cataract is age. However, in specific illnesses (such as diabetes) or in association with certain types of medication (steroids), there is an increased risk of cataract. Increased UV exposure can also lead to the development of cataract.
Symptoms of Cataract
The most common symptom is blurring of vision (Figure 1). Other symptoms may include colours appearing dull, glare and halos around lights, difficulty reading, watching TV or driving at night.
Treatment of Cataract
The only proven ‘cure’ for cataract is surgery. Contrary to popular belief, there is no eye drop or medication which can treat a cataract.
How Is Cataract Surgery Performed?
Modern cataract surgery is called phacoemulsification and involves the use of high frequency ultrasound (not laser) delivered through a handheld probe to break the cataract into little pieces and remove it. An artificial lens implant is then placed into the eye. The whole procedure is carried out through a wound of less than 3mm and no stitches are required. (Figure 2)
Advancements in Cataract Surgery
Cataract surgery is constantly changing and technological advancements in the machines as well as significant developments in the types of lenses have contributed to improved quality of vision as well as quality of life of the patient.
Challenging Cataract Surgery
There are many different types of cataract and to the ophthalmologist, the technical difficulties presented by the different types of cataracts during surgery is a very real issue and a challenging one.
Dense cataracts: A significant number of patients only seek help when they are almost blind from cataracts and in these cases, the cataracts would be very dense. In a dense cataract, more energy is required during surgery and there is an increased risk of damage to other structures within the eye.
Unstable cataracts: In certain circumstances such as in an inherited condition (Marfan’s syndrome) or following injury to the eye, the lens may be dislocated from its original position. Complicated manoeuvres to stabilize the lens will be required during surgery for these situations and should only be performed by an adequately experienced surgeon.
Small pupils: A dilated pupil is essential during cataract surgery but pupil sizes are variable and in certain conditions such as diabetes or glaucoma the pupil can be particularly small. The surgeon will be required to use various different techniques to mechanically ‘dilate’ the pupil in order to operate safely.
Cataract and Other Eye Diseases
Cataracts often co-exist with other eye diseases and in the appropriate hands, combined surgery can be carried out.
Cataract and glaucoma: Glaucoma is characterised by high pressure within the eye causing damage to the optic nerve. Patients lose peripheral vision first and eventually their central vision as well if left untreated. Glaucoma and cataract often co-exist and cataract surgery combined with trabeculectomy (a filtration procedure to lower eye pressure) can be carried out.
Cataract and diabetes: Diabetes can cause severe bleeding in the eye and this complication from diabetes is the leading cause of blindness in the working age group. Vitrectomy is a specialised microsurgical procedure which is often carried out in patients with severe diabetic eye disease. As cataracts are also more common in diabetics, combined cataract surgery and vitrectomy are often performed.
As illustrated above, there is a lot ‘more than meets the eye’ when it comes to cataract surgery. It is important that patients understand the options available to them when told they require cataract surgery. Discuss all visual requirements with your ophthalmologist to find out the best option for you.
It is also important that patients understand the potential complexity of cataract surgery. No doubt cataract surgery may be trivialised to be a simple procedure which takes minutes to perform, but patients should be aware that it is still an operation which carries with it certain risks and should not be taken lightly.
Finally, be aware of other conditions which may affect the eye as we age. Regular visits to your friendly ophthalmologist will go a long way in picking up problems early and nipping them in the bud.