The term “cataract” refers to a clouding of the natural lens in the eye. Cataracts often develop slowly and can affect one or both eyes. They result in blurred vision, poor night vision with increased glare, decreased contrast, and occasional double vision. The clouding of the central portion of the natural crystalline lens occurs very slowly. Therefore, many years may separate the beginning of cataract formation and a person becoming aware that their vision is no longer satisfactory. Poor vision caused by cataracts may also result in an increased risk of falling due to reduced vision and depression.
Cataracts are usually discovered and assessed during a routine eye examination. Symptoms such as blurred vision, fading colours with inability to distinguish accurately between shades, aversion to bright lights, seeing halos around lights, and difficulty seeing at night or in low light conditions, are all signs that a cataract may have developed.
Causes of Cataracts
The lens inside the eye works much like a camera lens, focusing light onto the retina for clear vision. It also adjusts the eye’s focus, letting us see things clearly both up close and far away.
The lens is mostly made of water and protein. The protein is arranged in a precise way that keeps the lens clear and lets light pass through it. But as we age, some of the protein may clump together and start to cloud a small area of the lens. This is what forms a cataract, and over time, it may grow larger and cloud more of the lens, making it harder to see. Though age is the major factor for developing cataracts, there are a host of other reasons for the lens of an eye to turn cloudy.
Besides advancing age, cataract risk factors include:
- Systematic disease
Lens proteins denature and degrade over time, however this process is accelerated by diseases such as diabetes mellitus and hypertension.
Blunt trauma causes swelling, thickening, and whitening of the lens fibres. While the swelling normally resolves with time, the white colour may remain. In severe blunt trauma, or in injuries that penetrate the eye, the capsule in which the lens sits can be damaged.
Cataracts can arise as an effect of exposure to various types of radiation. X-rays, one form of ionizing radiation, may damage the DNA of lens cells. Ultraviolet light, specifically UVB, has also been shown to cause cataracts coagulation caused by electric and heat injuries whitens the lens.
Infants may be born with congenital (inherited by family genes) cataracts, Congenital cataracts can result in amblyopia if not treated in a timely manner. The presence of cataracts in childhood or early life can occasionally be due to a particular syndrome.
- Skin diseases
The skin and the lens have the same embryological origin and so can be affected by similar disease. Those with atopic dermatitis and eczema occasionally develop shield ulcer cataracts.
Some medications, such as systemic, topical, or inhaled corticosteroids, may increase the risk of cataract development.
Nearly every person who undergoes a Vitrectomy—without ever having had cataract surgery—will experience progression of nuclear sclerosis after the operation. As such, for phakic patients requiring a Vitrectomy it is becoming increasingly common for ophthalmologists to offer the Vitrectomy combined with prophylactic cataract surgery to prevent cataract formation.
What’s the Treatment?
Cataracts can be removed only with surgery.
It is however not an urgent surgery therefore if your cataract symptoms are not bothering you very much, you don’t have to remove a cataract. If your vision can be corrected with glasses or contacts, your doctor will give you a prescription. If it can’t, and cataracts are a problem in your daily life, you may need cataract surgery.
How does cataract surgery work?
It’s done on an outpatient basis, meaning you’ll go home the same day, and it’s usually very successful. During cataract surgery, your eye surgeon will remove your eye’s cloudy natural lens. Then he or she will replace it with an artificial lens. This new lens is called an intraocular lens (or IOL). When you decide to have cataract surgery, your doctor will talk with you about IOLs and how they work.
As part of cataract surgery, an Intra-ocular lens (IOL) is implanted in your eye after the cataract has been removed. This lens is typically made from acrylic or silicone material, and is placed in your eye for the rest of your life time.
There are numerous strategies and choices for IOL placement. The doctor will provide information about the different choices. Please discuss this and ask questions before choosing any specific lenses.
Monofocal IOL (mono-vision)
This is the standard choice as a lens type. These lenses have a single power, meaning you will have vision “tuned” to be better for either near or far, but will require reading glasses or contact lenses for “fine-tuning”. Additionally, this lens does not allow you to vary your vision between near and far. The advantage of this lens is the good quality of vision & perceived lack of glare and diminished night vision. The cost of these lenses are also covered by most medical aids.
These intra-ocular lenses are premium IOL’s. They are modern IOL’s with different regions of power, meaning they provide the ability for you as patient to be able to see near and far after the surgery. Medical aids do not cover the cost of these lenses, and if you choose to implant these lenses, out of pocket expenses will be incurred.
If you are highly expectant of perfect quality of vision, or prone to fault finding with small details, then you should best avoid these lenses. The lenses are well known to cause glare (5%), haloes around lights (5%) and diminished contrast / night vision (5%) and are expensive.
The benefits of these lenses include greater range of vision and no-spectacle freedom. Like multifocal contact lenses, these premium IOLs contain added magnification in different parts of the lens to expand your range of vision so you can see objects clearly at all distances without glasses or contact lenses.
Multifocal IOLs are another category of presbyopia-correcting IOLs that can decrease your need for reading glasses or computer glasses after cataract surgery.
If you choose to implant the lens, and become unhappy with the quality of vision, the lens can be removed and replaced by a different lens. From research, it appears that about 1% of patients (therefore – very rarely) choose to have the lenses removed and replaced with a different lens. Re-operation could potentially also lead to further expenses which the medical aids may or may not cover.
Toric IOLs are premium intraocular lenses that correct astigmatism as well as nearsightedness or farsightedness. Like toric soft contact lenses, toric IOLs can correct astigmatism because they have different powers in different meridians of the lens. They also have alignment markings on the peripheral part of the lens that enable the surgeon to adjust the orientation of the IOL inside the eye for optimal astigmatism correction.
If you suffer from more than 1D of astigmatism, special intra-ocular lenses called toric lenses can be implanted at the time of cataract surgery to reduce the amount of astigmatism.
These lenses are now covered by some medical aids, although a co-payment might be required depending on the specific plan you are on. An alternative to the toric lens is making small corneal relaxing cuts at the time of cataract surgery so as to relieve some of the astigmatism.
This lens placement strategy uses monofocal IOLs (see above) of different strengths placed in both eyes. This is well tolerated by patients and represents the most cost effective means to attempt greater spectacle independence after cataract surgery. One eye (the dominant eye) corrects for distance vision and the other eye receives a stronger monofocal IOL so as to correct for near vision. As a combination then, the two eyes together will allow the patient to have good vision for near and distance, allowing them greater spectacle independence.
Mono-vision strategies require some getting used to, so it is often useful to do a contact lens trial for a week or two (To simulate the probable outcome) before implementation.
All of the above mentioned choices are available to you. The choices will be discussed with you, and depending on individual risk factors, preferences and medical aid cover, a choice of lens implant can be made.
Cost of premium IOLs
Premium IOLs have additional features not found in conventional monofocal IOLs and cost more than conventional IOLs. Unfortunately, medical aid companies do not consider these additional features as medical necessities. Therefore you will incur additional out-of-pocket expenses for your cataract surgery if you choose a premium IOL.
Medical aids generally do cover the cost of cataract surgery, including the cost of a conventional monofocal IOL (though a deductible amount may be required, depending on your policy).
If you choose a premium IOL like ones described above, typically you will have to pay the difference in cost between a conventional monofocal IOL and the premium lens implant. This out-of-pocket expense could range from R3000 to R18 000 per eye or more, depending on the type of IOL.
To fully understand your cataract surgery costs and coverage ask plenty of cost-related questions to our patient liaisons or our cataract surgeon before consenting to surgery, to avoid unpleasant financial surprises afterward.