Cataract is characterized by a clouding of the lens of the eye. It is caused by metabolites accumulating in structures that have no vascularization. The human body has two such spaces: the cornea and the lens. With time, the lens accumulates waste products from the overall metabolism, and becomes hardened. The greatest risk factor for cataract development is age, but smoking also increases the risk for an earlier development of cataract. Other risk factors include early onset cataract in the family, near-sightedness, UV radiation, diabetes, trauma and some medications like cortisone. However, cataracts will strike all of us at some point of life. There is no medication available to prevent the formation of cataract, nor is there any scientific proof of nutritional supplements preventing or stopping the development of cataract. The only cure for cataract is a cataract operation.
The symptoms of cataract vary according to the type of cataract in question and which layer of the lens is affected. Cataract can present in the anterior capsule causing photosensitivity especially prevalent in the dark. Cataract presenting in the posterior chamber causes more severe symptoms already in the early stages, although the results of examinations in a dark room might still give surprisingly good results. Cataracts in the centre of the lens stiffens and hardens the lens and causes near-sightedness, but a strong-contrasted vision examination might still give good results. A nearly sure sign of a developing cataract is a continuously increasing spectacle negative value as well as a continuously decreasing positive error in adult age. These changes require frequent updating of eye glasses; an increasing economical expense halted only by a cataract operation. Decades ago, the cataract was allowed to develop (ripe) to late stages before any procedures were considered. Back then the lens was removed from the eye through a rather large incision made by a freezed cryotip- an invasive technique no longer used. Today the surgical criteria to opt for cataract operation is not based on visual acuity or on eye medicine in Western Europe, but on factors concerning shortening of waiting lists. In other words, the criteria are political. According to the criteria, catarct operation is to be considered if the following conditions are met:
- The patient suffers from cataract
- The cataract causes reduced vision
- A cataract operation would increase vision aquity i. e. it would be advantageous
- There are no contraindications for the procedure
- The patient wishes to undergo the surgery
When suspecting cataract, you should see an experienced reputable eye surgeon. After a full examination, you can discuss the timing, benefits, risks and side effects of the surgery. It is equally important to examine the macula and visual nerve, as well as other structures of the eye to gain a full picture of the health status of the eyes. Personally, I recommend examining the eye with help of special lenses, ophthalmic photography, OCT examinations and visual field examinations to study and document the health of the eyes. Other structures like the chamber angle (affects eye pressure) and possible pseudoexfoliation of the lens should also be examined when planning the timing of the surgery. In many cases, postponing the surgery makes the procedure technically more challenging and increases the risks. Performing challenging surgeries is a part of the eye surgeon´s job, but in my opinion, increasing the risks in a procedure should not belong to a patien´s life. If your eye doctor stipulates belating the surgery and letting the cataract ripe, it is time to consult another doctor.
In the pre-examination the type and optical power of the artificial lense to be used in the surgery is determined. The options are to choose either a unifocal or a multifocal lens. With a unifocal lens, vision can be focused on objects either near or far, and eye glasses are then needed to see far or near, respectively (and vice versa). In case of astigmatism, where the cornea does not focus light evenly on the retina, a correcting surgery with a torical lens implant is strongly recommended. The decision on the type of lens cannot be made based on an eye glass prescription, since special equipment performing calculations of the parameters of the cornea is required, and apparatus is usually only found in specialized eye surgery units.
Ever so often patients choose to undergo a presbyopia surgery along with the cataract surgery. In such case, an artificial multifocal lens is implanted and the patient can focus on objects both near and far, entirely freeing the patient from eye glasses. The surgery itself is similar to cataract surgery as such, but the implanted lens is different. This multifocal lens, due to its structure, also does not have the unwanted properties and drawbacks as multifocal eye glasses have. You can read more about presbyopia surgery in the blog post discussing the matter.
The surgery is performed in local anesthesia, where topical anesthetic eye drops are administered to the surface of the eye. No injections are used. A small amount of anesthetic may be administered into the posterior chamber. The procedure is painless since there are no free nerve endings in the lens. In the surgery, the lens is first emulsified by ultrasonic energy, after which it is removed using a narrow tip. The capsule surrounding the natural lens is preserved and the artificial lens is implanted inside the capsule. The implanted lens stays in position with the help of special structures along its edges, so called haptes. Protective and volume-increasing agents, such as viscous drops, are used during surgery. These agents are removed at the end of the procedure and an antibiotic solution is administered. The surgery is pain free and takes 5-10 minutes per eye. Vision is usually fairly good immediately after the surgery, and completely restored shortly after the procedure. If the cataract is severe, making the procedure technically more challenging, the healing might take a few days. Postoperative care includes eye drops with cortisone and antibiotics, as well as artificial tears and irritation-reducing drops.
An eye examination can be carried out on the following day of the surgery, but the actual postoperative examination is done a month post-surgery. At this point, the optical power of possible eye glasses can also be determined.
Cataract affects us all. With high-quality treatment we can markedly improve the patient´s vision and quality of life. The risks are minor, the healing is quick and the result is permanent. Cataract cannot develop anew. However, there is a chance for so-called after-cataract, a condition where the posterior wall of the lens capsule thickens and vision becomes impaired. This condition is easily treated with a painless laser treatment of a few minutes. The timing of the surgery should not be procrastinated since it lower the quality of life and increases the risks in the operation. A visit to our eye clinic entails a thorough examination of the eyes, combined with the acquisition of detailed information about possible procedures. The responsibility of the quality of the care is in your doctor´s hands- make sure to insist on the best possible examination and care of your eyes.