By Patrick Tracey MD
IN YOUR GOOD BOOKS

MANUAL SMALL INCISION CATARACT SURGERY: KEY TO REDUCING BLINDNESS IN DEVELOPING WORLD

There is little doubt that ultrasonic phacoemulsification has become the gold standard for cataract surgery in the developed world since Charles Kelman first invented the technique for cataract removal in 1967. However, this method of phacoemulsification is of limited use in many developing countries, because of the high cost of basic equipment, the extra surgical training required and the density of the cataracts, which are found in these regions. This is unfortunate as it is accepted that the developing world is where most of the present cataract blindness backlog exists. Given such surgical challenges, manual small incision cataract surgery has now emerged as the first practical alternative to providing phacoemulsification, especially as it can achieve rapid postoperative recovery with minimal surgery related complications.

The Clinical Practice in Small Incision Cataract Surgery by Jaypee Brothers Medical Publishers, New Delhi represents the first book to reflect this new era of cataract surgery. The 633 page text is edited by a group of international ophthalmologists – Ashok Garg MD, Luther L. Fry MD, Geoffrey Tabin MD, Francisco J Gutierrez-Carmona MD and Suresh Pandey MD.

The colourful volume aims to provide the latest knowledge on modern techniques in small incision cataract surgery to ophthalmologists who are interested in manual small incision cataract surgery. It is divided into four sections, which cover many topics, including preoperative evaluations, minimal incision techniques, postoperative complications and management and recent advances in nucleus delivery and intraocular surgery. The four sections are further subdivided into 57 chapters, which are well illustrated with photographs of injection techniques and anatomical diagrams. The first chapters deal with the anatomy and biochemistry of human crystalline lens; while the third chapter is a rather comprehensive review of the aetiology of cataracts by David Meyer MD from South Africa . The fourth chapter, which deals with the various treatment modalities of cataracts, is written by one the editors, anterior eye surgeon, Ashok Garg MD. Dr. Garg beautifully illustrates various anaesthesia techniques, cataract classification and treatments. The diagrams on phacoemulsification and foldable IOL implantation – courtesy of Ciba Geigy – are especially helpful.

The next chapters, by Drs. Sunita and Amar Agarwal delve into the issues of optical and acoustic biometry and sterilisation. The authors detail the history of sterile techniques, operating theatres, methods of sterilisation and methods of obtaining culture specimens. Reading the chapter, one is left with a feeling that it is devastating for any surgeon to be faced with post operative infections, but this complication is particularly poignant in the developing world. One is also reminded that we now take many surgical procedures for granted in our more developed environments. The next chapters tend to deal with the real reason that this expansive book was formulated, that of detailing recent surgical advances in viscoelastic substances and solutions as well as documenting the techniques of small incision cataract surgery. I was interested to learn that sodium hyaluronate was first used as a replacement for vitreous and aqueous humour as early as 1972.

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The beneficial and popular use of methylcellulose in this environment makes sense in terms of its lower cost, larger quantity of the material per unit and the fact that there is no requirement for refrigeration. Again, the use of this material must be seen in the overall context of a third world setting. The next chapters deal mostly with the dynamics of small incision cataract surgery and surgical techniques utilised in the various operative steps. Jean-Marc Legeais MD from France deals with modern IOL materials and IOL implantation techniques through small incision surgery. There is another chapter dedicated to the Blumenthal technique, which has stood the test of time since its introduction in the early nineties.

There is substantial information in the next section regarding manual phacofragmentation and phacosection techniques. M.S. Ravindra MD includes some well chosen photographs – apparently from his own patients – to illustrate the techniques. Arum Kshetrapal and Ramesh Kshetrapal then describe small incision cataract surgery in such difficult situations as when a patient has a small pupil, white cataract or black cataract. There is also a section on sutureless cataract surgery with nucleus extraction by the fishhook technique, the jaws slider pincer technique and the double wire snare splitter technique for small incision, non phaco cataract surgery. The ophthalmologists describe in extensive detail how to manage complications from the anterior and posterior segment. They also describe the aetiology, clinical manifestations, and pharmacological prevention of posterior capsule opacification, a problem still to be resolved.

Before the end of this 632 page volume is a chapter on the management of dislocated lens and lens fragments. Finally, there is a section on paediatric cataracts and an update on 21st century cataract-intraocular surgery, which describe some of the advances that are going to happen in this exciting part of ophthalmic surgery over the next few years. This includes details about ultra small incision cataract surgery and implantation of rollable lens. The author also addresses efforts that are being made to restore accommodation and eradicate posterior capsule opacification. There are also 2 CDs laden with worthwhile videos on small incision cataract surgery.

In essence, this book provides a missing reference text for performing extracapsular surgery in the developing world, where phacoemulsification is not always appropriate. It also provides a cogent argument for using manual small incision cataract surgery to address the growing backlog of cataract blindness in the developing world. In so doing, the authors have created a beautiful, well illustrated text that should form part of the everyday practical library of cataract surgeons – whether they practice in the developing world or developed world.

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Book a product of international collaboration
Ophthalmologists from nine countries collaborated to contribute and edit Clinical Practice in Small Incision Cataract Surgery. The editors include Luther L Fry MD, Clinical Professor at the Kansas School of Medicine; Geoffrey C Tabin MD, Professor of Ophthalmology at the University of Vermont College of Medicine; Francisco J Gutierrez-Carmona MD from the University of Madrid; Ashok Garg, MD, Medical Director of the Garg Institute, in Hisar, India; and Suresh Pandey MD, of the Department of Ophthalmology at the University of Utah.

Poor cataract surgery outcomes in some areas of developing world pose concern

While the quality of cataract surgery is generally high in such developing world projects like the Nepal-based Himalayan Cataract Project, there is nonetheless some concern about outcomes and follow-up across Asia more generally, especially in rural areas. A 2003 study by Dr Lalit Dandona and colleagues at the Prasad Eye Institute in Hyderabad , India , showed that nearly 40% of the people who had undergone cataract surgery in a population-based sample were blind after surgery – in a third of these cases from cataract-surgery-related causes. While the number of patients in the study was small, similar figures have been reported from population-based and clinical studies in other areas of Asia , including Pakistan , Bangladesh and even eastern Nepal .

Such disappointing figures have been ascribed to the seduction of quantity over quality, but a major problem is uncorrected refractive error. In the Sivaganga Eye Study in India , for example, 13.8% of 682 cataract-operated patients in the population-based sample had visual acuity worse than 6/60 in both eyes, usually as a result of uncorrected aphakia or other refractive error. The strongest predictors of poor visual acuity were illiteracy, rural residence – and, somewhat dispiritingly, surgery in largely inadequate government facilities. Other studies have reported severe visual impairment (defined by WHO as <6/60) in as many as 58% of post-cataract-surgery patients – of whom 19% still had very poor vision after best correction.

The problems with uncorrected refractive error are mitigated by ECCEs and IOL implants, Dr Tabin told EuroTimes. "One of the problems we faced when I first came to Nepal was that only a few per cent of cataract extractions were ECCEs and the rest were ICCEs, with aphakic spectacle correction. Today in Nepal , 97% of cataract extractions are extracapsular, with IOL implants, whereas in India and China it's still more like 50%; in Bangladesh and Pakistan it's about 35% to 40% – and it's much lower in Africa . With extracapsular surgery we're getting much better results – as good as I get back in Vermont – and this means that we're getting more people coming forward for surgery. That's by far the best advertisement for cataract surgery."

Good results are achievable even in the most difficult circumstances, given the motivation to succeed. Dandona and colleagues found that only 3.1% of eyes and 1.8% of persons were blind after surgery in two rural eye centres that ‘pay particular attention to the quality of eye care.' Similarly, teams from the Lahan Eye Hospital and the Tilganga Eye Centre in Nepal reported excellent results after carrying out a total of 2,167 cataract extractions in six days in 2001 to mark World Sight Day. Of these cases, the uncorrected visual acuity at discharge was 6/6 to 6/18 in 49.9% of eyes, and less than 6/60 in just 3% of eyes.

"The key to success is selecting and training local people who really care, who really want to make a difference, people who go on to become energetic leaders like Dr Ruit and Dr Pham Binh in Vietnam," said Dr Tabin. "If you don't select in this way, it's easy to end up training people who don't care, who migrate away from the rural areas where they can make a big difference, and go off to the cities for a comfortable life, charge for a few operations, and send their kids off to private schools – and who am I to criticise that, with my comfortable life back home in Vermont? Unfortunately, there will always be some doctors who just don't care – who do a 12 mm incision, use 9/0 nylon suture and end up with 10 dioptres of astigmatism, or capsular rupture, or posterior capsular opacification – and they say, ‘It's God's will'. It's not. It's bad surgery."

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