Cataract or Lens Replacement Surgery is one of the most often performed eye surgery operations both here in South Africa as well as around the globe. This surgery is undertaken when the natural lens of the eye known as the crystalline lens needs to be replaced due to an opacification of the lens. This opacification is referred to as a cataract and the natural lens is replaced by an intraocular lens.
What Causes Cataracts?
Cataracts can be caused by metabolic changes of the crystalline lens fibres which over a period of time will result in the development of a cataract. Additionally, certain environmental factors can lead to cataract formation. In rare cases, infants can also be born with congenital cataracts. No matter how the cataract is formed however it will result in either impairment or even complete loss of vision in the affected eye.
Symptoms of cataracts during the early stages of development include glare sensitivity from lights and small light sources at night. It can also result in reduced acuity at low light levels.
What Happens During Cataract Surgery?
When cataract surgery is performed the cloudy natural cataract lens of the eye is removed. This is done through either emulsification or by surgically cutting it out. It is then replaced by an artificial intraocular lens or IOL for short. This surgical cataract procedure is performed by an ophthalmologist in a surgical centre or hospital and not normally in an inpatient setting. To ensure that little or no discomfort is experienced by a patient topical, peribulbar, or even retrobulbar local anaesthesia is used during the cataract surgery.
The Advantages of Cataract Surgery
More than 90% of all cataract surgical operations are successful in restoring useful vision in a patient, Additionally, the procedure has the advantage of incurring a low rate of complications, normally only needs daycare, can be performed quickly, is minimally invasive and has a quick post-op recovery period.
Types of Cataract Surgery
Ophthalmologists have a number of different surgical techniques which they can utilise during cataract surgery. These in no particular order are as follows:
Phacoemulsification or Phaco
This is one of the most common forms of cataract surgery and involves the use of a medical apparatus which has an ultrasonic handpiece which is equipped with a titanium or steel tip. This tip vibrates at an ultrasonic frequency of 40,000 Hz and is used to emulsify the lens and cortical material. In some instances, a second instrument might be used to further break the nucleus into smaller pieces, as it helps to make the emulsification process a little easier. After the phacoemulsification of the lens nucleus and cortical material is completed, a dual irrigation-aspiration (I-A) probe or a bimanual I-A system is used to aspirate out the remaining peripheral cortical material.
Manual Small Incision Cataract Surgery
Also known as MSICS, Manual Small Incision Cataract Surgery is a surgical technique in which the entire natural eye lens is expressed through a medically induced self-sealing scleral tunnel wound.
Extracapsular Cataract Extraction
Also known as ECCE, Extracapsular Cataract Extraction is the removal of the entire natural eye lens in a manual expression process which leaves the posterior capsule (also known as the elastic lens capsule intact. This is done to allow for the implantation of an intraocular lens. This cataract surgical procedure is normally used when the cataracts are very hard or when phacoemulsification is not an option.
Intracapsular Cataract Extraction
Also known as ICCE, Intracapsular Cataract Extraction is the removal of the lens and the lens capsule in one piece. This surgical procedure is rarely used anymore due to a higher rate of complications due to the large incision required as well as the additional pressure which is placed on the vitreous body of the eye.
Femtosecond Laser-assisted Cataract Surgery
A popular form of Cataract Surgery which is performed in place of manual phacoemulsification cataract surgery. It has the same visual, refractive and safety benefits as the manual phacoemulsification procedure.
What is an Intraocular Lens?
An IOL is a lens which is implanted in the eye as part of a treatment for cataracts and myopia. There are two types of Intraocular Lenses which are commonly used during cataract surgery, which are as follows:
A Pseudophakic IOL is implanted during cataract surgery, after the cloudy eye's natural lens which is forming the cataract has been removed. This type of IOL provides the same light focusing function as the natural crystalline lens found in the eye.
Phakic Intraocular Lens
Also known as PIOL, this is an Intraocular Lens which is placed over the existing natural lens. It is commonly used in refractive surgery to change the eye's optical power. It is usually used as a treatment for myopia, which is also known as nearsightedness, and not cataract surgery.