Cataracts form in the human eye with aging. Fortunately, in almost all instances, it is treatable and in the modern era, cataract extraction with insertion of an intraocular lens remains the most successful and medically necessary procedure. In the first of a 2 part write up, Dr Chuah Chin Tek sheds light on what cataracts are, what patients perceive, and what treatment entails. In the second part to be published in the next issue of this magazine, he will write on the many options available as regards to intra-ocular lenses. Also a real patient will share her perspective of the entire treatment experience from presentation of her symptoms, through the treatment procedure, to post-operative care and outcome.
In keeping with significant advances in medicine, eye care has also evolved largely due to major improvements in both the surgical techniques as well as instrumentation. While cataract remains the major cause of visual loss worldwide, patients may be comforted to know that cataract surgery, one of the most common, and arguably the most successful surgical procedure in medicine, has benefitted greatly from key changes in surgical technique, instrumentation and intra-ocular lens technology.
A cataract is a clouding of the lens – the structure in the eye responsible for focusing light rays entering the eye so that we can see. As we age, the lens loses its transparent state, and what follows is the formation of a cataract. There are also other types of cataracts, such as those resulting from trauma and those associated with use of certain drugs. But, by far, the commonest category is senile cataracts associated with aging. Cataract morbidity is responsible for 47.8% of the world’s total blindness.
Presenting Symptoms
Patients complain of blurring of vision, visual distortion and a general deterioration in the acuity (sharpness) of images seen. They may also complain of glare, need more light to read, have poorer night vision or see faded colours. The disease usually progresses slowly. It is not uncommon to see patients presenting only when they cover one eye (the better eye) to discover that their vision is very poor. Occasionally, patients may have been told that they have worsening myopia by their optometrists or opticians. The thickening or progressively denser cataract has a higher refractive index and bends light more, leading to a ‘pseudo myopic state’. For this the definitive treatment is cataract extraction with intraocular lens implantation.
To minimize the most feared complication of the procedure, infection or endophthalmitis, the patients are instructed to observe good eyelid hygiene and is prescribed antibiotic eye drops to be instilled three days prior to surgery.
The procedure is performed either under topical or regional anaesthesia. Patients are instructed to arrive 2 hours prior to the procedure so that the necessary preparation can be carried out, and they can leave for home on the same day once it is deemed safe (some patients are sedated and so are monitored for some time post operatively). Patients are reviewed the day after surgery, with many performing a second check within the first 5-6 days. Patients can resume their normal lifestyle routines soon after.
Treatment
The problem of cataract visual loss, though common, is reversible. The cloudy lens is removed using the latest techniques via a small incision that does away with the need for stitching, and an artificial lens is inserted in place of the cataract. This method of cataract removal, phacoemulsification, utilizes ultrasound energy to help the surgeon break the cataract into smaller pieces, emulsify the cataract, following which it is aspirated. This key development by Charles Kelman as early as 1967, was followed by further refinements that ultimately resulted in smaller and smaller wounds. Wound sizes today are no wider than 2.75mm and 1 mm wounds are not far away. Advances in our understanding of fluidics also resulted in safer and more efficient phacoemulsification machines. Close collaboration through research and constant feedback to the industry by eye surgeons result in technological advances that enhance the safety profile and outcome of this procedure, with the ultimate beneficiary being the patient with cataract.
Recovery is swift with this method of surgery and success rates are high at almost 100%.
Prior to surgery, the surgeon takes a detailed history looking out for medical issues that need to be addressed such as a history of diabetes, hypertension or ischemic heart disease. The patient undergoes a series of tests to ascertain the power of the intraocular lens that will be inserted. This includes the measurement of the optical length of the eye as well as the focusing power of the cornea. The entire process is known as biometry, and even this part of the entire process has seen tremendous research, advances and ultimately, greater accuracy in the placement of the intraocular lens.
Conclusion
In the next article on cataract treatment, we will discuss the many options available as far as the choices of intraocular lenses are concerned. It is hoped that these 2 articles will describe the entire process from the patient’s perspective, including the real choices spelt out to the patient by their attending surgeon, and will help in a better understanding of a procedure that has often been described as the most successful elective surgical procedure.
Dr Chuah Chin Tek, medical director of The Eye & Aesthetics Clinic and Consultant at Mount Elizabeth Medical Centre, has been in practice for 19 years. He graduated MBBS (Singapore), and was admitted to the specialist register after his ophthalmology training. He sub-specialised in ophthalmic plastic and reconstructive surgery, having trained under the top oculoplastic surgeons in Singapore for two years and secured the prestigious Higher Manpower Development Plan Award to hone his skills in advanced oculoplastics surgery and management of complications of blepharoplasty in Salt Lake City, USA. Dr Chuah also holds a diploma in aesthetic medicine from the American Academy of Aesthetic Medicine and is currently practising in Suntec City and Mount Elizabeth Medical Centre.