The Evolution of Cataract Surgery

Controversies Through the Ages

Abstract

Cataracts have been in public consciousness since ancient times. Throughout the ages, the comfort of established practices, at times, has obstructed the implementation of improved policies. The opposition to lensectomy, hygiene practices, intraocular lenses, and phacoemulsification (phaco) are explored. As femtosecond laser cataract surgery attempts to secure a foothold in cataract treatment, we consider whether it is destined to be a forgotten footnote or if, like other contributions to the history books, the difficulties of establishing a new technique are abstracting the benefits represented.

Cataract treatments have been in existence since antiquity. Yet, they remain the leading cause of blindness worldwide.¹ Surgical evolution has been cautious, with the earliest recorded method, couching, retaining favor from its first mention in Hindu manuscripts circa 600 BC until the mid-18th century.

From the earliest documentation, treatment methods and expected results have been a source of controversy. The code of Hammurabi (1750 BC) described a payment structure for services, which included removal of the surgeon’s fingers if ocular loss or death occurred as a consequence of the procedure.² Although reticence to change is an oversimplification of complex social and economic interactions, the continued practice of couching despite poor results serves as testament to the innovator’s struggle.³

In this article, we review the archives and explore the skepticism with which many of the cornerstones of current ophthalmic practice were initially met. We consider femtosecond laser cataract surgery (LCS) and question what impact it may have. Does it deserve to be relegated to the realm of historical text or are opponents allowing shortsighted obstacles to obstruct the true potential represented?

COMPETITION FOR COUCHING: EXTRACAPSULAR SURGERY AND INTRACAPSULAR SURGERY

A French surgeon, Jaques Daviel, first introduced extracapsular cataract surgery as an alternative to couching in 1748.⁴ Daviel’s procedure heralded the birth of the cataract operation we know today.

However, victory did not arrive easily for the new technique. Debate raged over the century that followed with passionate adversaries arguing virtues of both methods. Two such contemporaries were Samuel Sharp and Percival Potts. Both were accomplished surgeons and pioneers within the profession.⁵ Despite similarities in other respects, their opinions regarding the new cataract technique could not have been more polarized. Based on evidence derived from his experience with Daviel’s method, Sharp was a proponent and recognized scope for further improvement. Potts failed to entertain the concept from its inception, believing its advocates greatly exaggerated the benefits reported. However, his derision was not as retrograde as it may appear in hindsight. His failure to recognize promise in the new method was based on a patient-centered concern. He was striving to promote the least invasive and technically demanding operation capable of producing acceptable results. This concept is one of the fundamental precepts of surgical management today.⁵

Over time, cataract removal superseded lens dislocation with modified versions of Daviel’s original procedure gaining widespread acceptance. The adjustment made by Samuel Sharp⁶ actually represented the first described intracapsular method of cataract extraction. Henry Smith,⁷ an Irish ophthalmic surgeon, created a brief resurgence in the popularity of the intracapsular technique in the early 20th century. Smith was a prolific surgeon and published a large volume of results impressively arguing his case for the intracapular technique. In the year up to May 1905, he performed 2616 intracapsular cataract extractions (ICCEs), reporting lower incidences of inflammation and infection coupled with better visual acuities than were being achieved with extracapsular cataract extraction.⁷ Barraquer’s⁸ discovery of the zonule lysing enzyme, α-chymotrypsin, complimented Krwawicz’s⁹ introduction of cryoextraction in further advancing the case for intracapsular extraction.

Both methods retained supporters throughout the first half of the 20th century. However, with the development of the intraocular lens (IOL) and growing popularity of phacoemulsification, extracapsular cataract extraction began to supersede ICCE as the operation of choice. The resounding death knell for ICCE came when vitreous was declared an enemy, and the protective role of the capsule was recognized.^10,11

ANTISEPSIS

Oliver Wendell Holmes and Ignaz Philipp Semmelweis were initially ridiculed when, independently, they each arrived at a similar conclusion. Despite significant objective evidence, respective colleagues on opposite sides of the Atlantic shunned the notion that poor hand hygiene was contributing to the spread of disease in maternity wards.¹² Joseph Lister¹³ furthered the cause of antisepsis by recognizing the role of microorganisms in the etiology of infection. Influenced by the work of Louis Pasteur, he set out on a quest to find a substance capable of eradicating “septic germs.” He first assessed the effect of packing carbolic acid–infused cloths into the wounds of patients with compound fractures. Generally condemned to amputation with high perioperative and postoperative mortality and morbidity, these patients began to survive without disabling disfigurement. ¹³ Lister’s prioritization of education led to widespread circulation of his ideas. He reported his findings in a series of publications in The Lancet and British Medical Journal and presented them at a landmark meeting of the British Medical Association in Dublin in 1867.¹³ Alfred Graefe¹⁴ was first to record his experience with the new precautions as they pertained to cataract surgery. Loss of eyes following implementation of his antiseptic regimen dropped from 4% to 10% to 1% to 2% when instruments, lids, and conjunctival sac were treated preoperatively, perioperatively, and postoperatively. His technique incorporated the use of 2% carbolic acid for ocular surface treatment, alcohol treatment of instruments utilized, and boric acid–infused cloths to drape and bandage.¹⁴ Over the century that followed, antiseptic methods evolved, and improved surgical technique continued a downward trend in infection rates. However, as with most evolving practices in the medical realm, change was slow. As a case in point, iodine was first noted to reduce ocular flora in 1951.¹⁵ Yet, it took 40 years for a study demonstrating reduced endophthalmitis rates with the use of 5% povidone-iodine to be published.¹⁶ Preoperative antisepsis with povidone-iodine is now a routine step in ophthalmic surgeries.

ANAESTHESIA AND VISUAL AIDS

For centuries, surgeons performed cataract extraction without the assistance of visual aids. Poor visualization was further exacerbated by the likelihood of a vigorously mobile patient before the discovery of suitable anesthesia. It was an ophthalmologist colleague of Sigmund Freud, Karl Koller, who proposed topical cocaine as the first plausible solution to the latter dilemma. His findings were presented to the International Ophthalmology Meeting in Heidelberg in 1884.¹⁷

Hermon von Helmholtz gifted the profession with his invention of the ophthalmoscope. This allowed noninvasive visualization of the retina, greatly broadening the diagnostic scope of fledgling ophthalmologists.¹⁸ Pharmaceutical mydriatics have continued to evolve since atropine was first synthesized from Belladonna Atropa in 1831, allowing the ophthalmoscope to achieve its full diagnostic potential.¹⁹ In terms of cataract surgery, mechanical devices such as iris-retractor hooks, polymethylmethacrylate pupil dilator rings, and Beehler pupil dilators continue to develop, enabling sustained pupil dilation in particularly resistant subjects.²⁰ The introduction of ophthalmic viscosurgical devices to ophthalmology in 1972 has also improved maintenance of pupil shape and anterior chamber depth perioperatively.²¹

FROM APHAKIA TO PSEUDOPHAKIA

Procedures to remove cataracts have been available for centuries. However, the success of these operations, if measured in terms of visual restoration, has been dubious, at best, for most of this time.

Although the introduction of spectacles and subsequent advent of contact lenses provided life-changing visual improvement for those with refractive errors, aphakic refractive correction was fraught with complications. Lenses required were cumbersome and produced significant and disabling aberrations.

An incidental observation was responsible for the first truly inspired means of refractive correction following lensectomy. When Harold Ridley²² served as ophthalmologist to the fighter pilots of World War II, he noticed that shards of the polymethylmethacrylate/glass hybrid windscreen material did not elicit the expected foreign body response when they became lodged in patients’ eyes. Using similar material, he proceeded to perform the first IOL replacement and subsequently presented his operation to colleagues at the Oxford Ophthalmological conference on July 9, 1951.²² Despite having already accumulated several positive, relatively long-term results, his surgery was condemned by some of the most respected academics of the time as unnecessary and even reckless. Owing to the apathetic reception received, these devices did not come into mainstream practice until the 1970s to 1980s.

Charles Kelman²³ was visiting his dentist in the 1960s when he came across the seed of an idea that would spawn arguably the most significant advance in 20th-century cataract surgery. Like Kelman, his dentist Larry Kuhn, was an innovator using a new ultrasonic device to remove dental plaque.²³ Kelman immediately recognized its potential for cataract surgery. He had long been considering methods to fragment the lens to facilitate its removal through smaller orifices than were being used at the time, thus reducing the antecedent inflammatory, infective, and astigmatic effects of large incisions. In 1967, the first human procedure was performed on a blind eye resulting in endophthalmitis and phthisis bulbi.²³ Undeterred, Kelman persisted, with subsequent ventures proving more successful. He proceeded to teach the method to interested parties. Converting established and proficient intracapsular surgeons to this technically challenging, as yet unproven technique was an uphill struggle. Many sought to find fault with the new procedure. Initial concerns centered on several valid observations. The new operation had a prolonged learning trajectory with newly initiated surgeons taking 100 cases to reduce their complication rates to intracapsular levels.²⁴ The machine and instrumentation represented a significant initial outlay, and with intracapsular extraction boasting complication rates of only 3% to 5% and initial studies demonstrating no significant advantage from the perspective of visual outcome, the debate as to whether this was a justifiable investment remained valid for many years after its first inception.²⁵ Phacoemulsification had largely infiltrated mainstream practice within the developed world before the emergence of research exonerating it as the procedure of choice. Review articles comparing phacoemulsification to alternative methods of extraction have found that it consistently provides the best outcomes in terms of vision and complication rates.^26,27

In 1984, the Food Drug Authority approval of Mazzocco’s²⁸ foldable IOL allowed phacoemulsification to showcase its true potential. Before this, the operation would be completed through a 3-mm incision to the point of IOL introduction, at which stage the wound required enlargement to 6 to 8 mm, negating the effort of operating through the smaller incision.²⁸ With the introduction of the foldable lens, 3 mm incisions became achievable. More recently, the trend has moved toward microincisions, with the main wound measuring just 1.8 mm.²⁹

THE CONTRIBUTION OF LASER

Laser technology has carved a niche as a treatment adjunct across many ophthalmic subspecialties. Dr Aron-Rosa and colleagues’ introduction of noninvasive yttrium aluminum garnet (YAG) laser capsulotomies in 1978 made posterior capsular opacification a far less significant concern.³⁰ Dodick and Christiansen³¹ developed the use of the Nd:YAG laser to fragment the lens in 1989. Kanellopoulos’³² multicenter trial of 1000 cases provided promising safety and efficacy data. The shorter pulse duration of femtosecond laser offered enhanced precision with a reduced risk of damage to adjacent tissue. Zoltan Nagy³³ was the first to perform LCS in Hungary in 2008.

DISCUSSION

To quote Max Planck: “A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.”³⁴

Cynical as his sentiments sound, history would seem to find resonance with his claim. As described above, many established innovators became cautious of new ideas once installed in positions of influence.

Proponents of femtosecond argue that enhanced precision of laser created incisions, capsulorrhexis, and nuclear fragmentation facilitate lens centration and lead to reduced aberrations and more accurate refractive outcomes for patients.^35,36 Studies have impressively demonstrated the stronger, more reproducible capsulorrhexis created using the technique.^35,36 They have also provided evidence of the improved lens positioning advertised in the propaganda.^36,37 However, whether these alterations translate to improved patient experience has yet to be proven. Similar to phacoemulsification, initial experiences of skilled cataract surgeons with the new technology demonstrated a definite learning curve.^38,39 This technology, like phacoemulsification, also demands alterations to be made to facilitate its adoption.³⁵ A dedicated laser room, trained staff, and the femtosecond machine itself all necessitate a significant initial financial outlay. With governments in the midst of global financial turmoil, justifications for heath expenditure are being increasingly scrutinized. For these reasons, some warn that LCS represents a “pseudoinnovation” of the type lamented of in E. Emanuel’s⁴⁰ contribution to The New York Times last May.

Whether this new technology really represents a new era in mainstream cataract surgery or if it will remain an isolated enclave for the preferences of a select few remains to be seen. However, to dismiss the procedure based on the existence of a satisfactory alternative may be to repeat the errors of the past in dismissing the visionaries of the present.