COM M E N TA RY

1032 VOLUME 10 | NUMBER 10 | OCTOBER 2004 NATURE MEDICINE

Cataracts are the major cause of reversibleblindness throughout the world, affectingabout 20 million people. Until 1970, cataractswere the leading cause of blindness in theUnited States. Today, in the United States andother industrialized countries, cataracts areno longer a significant cause of blindness.This achievement can be traced in large partto the development of a simple, small-inci-sion cataract operation pioneered by CharlesD. Kelman, this year’s recipient of the LaskerClinical Medical Research Award (Fig. 1).The outpatient procedure pioneered byKelman, called phacoemulsification, has nowbecome the most commonly performed elec-tive surgical operation in the western world.In the United States alone, nearly 3 millionKelman-type cataract operations were per-formed last year1.

Cataracts occur when the clear crystallinelens of the eye becomes clouded, resulting inpartial or complete loss of vision. Althoughcataracts result from many conditions (suchas trauma, genetic diseases and diabetes), themost frequent cause is the natural agingprocess. More than one-half of the popula-tion older than 65 years develops impairedvision caused by cataracts. There are no diets,drugs or eyedrops that will make a cataractdisappear; the only treatment is surgicalremoval. Historically, cataract surgery is oneof the oldest operations, second only to cir-cumcision.

Before Kelman—inpatient cataract surgeryIn 1970, before the era of Charles Kelman, thesurgical removal of cataracts was a majorordeal, requiring a hospital stay of 10 days (ifno complications occurred) and a convales-cence of several months2. Typically, thepatient underwent general anesthesia, afterwhich a large, semicircular (180°) incisionwas made in the cornea to allow the entirelens to be grasped with a forceps and pulled

from the eye in one piece. Eight or moresutures closed the incision, and the patientwas kept on absolute bed rest for 3–5 dayswith both eyes occluded with patches. Torestrict movement of the head, sandbagswere placed along both sides of the head, andboth wrists were bound with restraints to thebed. This enforced immobilization often ledto mental disorientation, prostatic obstruc-tion, bedsores and pulmonary embolism. Asmany as 20% of patients developed vitreoushemorrhage, macular edema, eye infectionsand retinal detachment. After discharge fromthe hospital, the eyes and lids remained red,swollen and irritated for as long as 6 weeks.The surgically treated eye had to be patchedfor several months, and the aphakic patienthad to wait for as long as 6 months to be fit-ted with thick spectacle glasses.

In the early 1950s, an important advancein cataract surgery occurred with the inven-tion of the artificial intraocular lens byHarold Ridley, an ophthalmologist at St.Thomas and Moorefield Eye Hospital inLondon3. Ridley’s invention was conceptu-ally quite radical and went against the long-standing dogma that a foreign body, such asa plastic lens, should never be placed into thedelicate tissues of the eye. The vast majorityof ophthalmologists were slow to embracethe use of intraocular lenses in their cataractoperations. The full impact of Ridley’sinvention was not realized until the late1980s, with evolving improvements in thedesign of more flexible types of intraocularlens. The demand for a better lens was stim-ulated in large part by the increasing use ofKelman’s new phacoemulsification proce-dure, as described in the following para-graphs.

After Kelman—outpatient cataract surgeryIn 1967, while Kelman was a staff ophthalmol-ogist at the Manhattan Eye, Ear and Throat

Hospital in New York City, he published anarticle describing a totally new approach thatwould, over the next 25 years, ultimatelyreplace traditional inpatient cataract surgerywith a much less intrusive and more curativeprocedure that could be performed on an outpatient basis4. Kelman called his proce-dure phacoemulsification (phako being Greekfor ‘lens’; emulsi for ‘milked out’). In its cur-rently practiced form5–7, phacoemulsificationinvolves making a small, self-sealing incisionin the cornea (3° in contrast to the traditional180°) and then inserting an ultrasonic probe,the vibrations of which (40,000 per second)break and liquefy the cataractous lens withoutdamaging the surrounding tissues. The emul-sified fragments of the lens are then suctionedthrough the sonic tip, and a foldable intraocu-lar lens (made of acrylic or silicone) is inserted

How a jolt and a bolt in a dentist’s chairrevolutionized cataract surgeryJoseph L Goldstein

Figure 1 Charles D. Kelman (1930–2004),recipient of the 2004 Lasker Clinical MedicalResearch Award died on June 1, 2004, severalmonths before the Lasker Awards ceremony.

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COM M E N TA RY

NATURE MEDICINE VOLUME 10 | NUMBER 10 | OCTOBER 2004 1033

through the small incision. Once inside theeye, the flexible lens unfolds like a parachute,and visual acuity is typically restored to 20/20or 20/40. There is no longer a need for thethick, unattractive and optically poor specta-cles that were common in the pre-Kelman era.

The entire procedure, which can be donein 5–10 minutes, is performed on an outpa-tient basis under topical or intraocular anesthesia. Because the eyelids are not anes-thetized, no eye patch is required and recov-ery is almost immediate. The genius ofCharles Kelman—the discovery that small-incision phacoemulsification allows rapid,painless restoration of vision—is reminiscentof the genius of Ray Kroc, the founder ofMcDonalds. Kroc discovered that people liketo be served in 60 seconds—a discovery thatchanged the eating habits of the entire world.Charles Kelman’s discovery changed theoperating habits of ophthalmologists.

An epiphanous moment in the dentist’schairThe idea for phacoemulsification came toKelman in 1964 while sitting in his dentist’schair and having his teeth cleaned. A suddenjolt from the dental drill produced anepiphanous bolt from the blue. As Kelmanwrites in his memoir8, “I sat in his chair, as hereached over, took a long silver instrumentout of its cradle and turned it on. A fine mistcame off the tip but the tip didn’t seem to bemoving. He applied the tip to my teeth, and Ifelt an exquisite vibration and heard a high-

pitched sound.” Kelman asked, “What is thatthing?” The dentist replied, “An ultrasonicprobe.” “I knew this was the moment,”Kelman wrote8.

After this epiphanous moment came sev-eral years of intensive research on the eyes ofcats and human cadavers until the pha-coemulsification technique was first used ona patient in 1967. By 1969, Kelman had usedhis procedure to remove cataracts in 12patients9. Between 1967 and 1973, 3,500cataract removals by phacoemulsificationhad been performed in the United States, 500of them by Kelman10. The vast majority ofophthalmologists viewed phacoemulsifica-tion as a radical procedure that totally chal-lenged their conventional wisdom. Inparticular, they were shocked by Kelman’saudacity in discharging his hospitalizedpatients on the same day as the surgery andpermitting them to return to full activity onthe first or second postoperative day7,10,11.Today, we take outpatient cataract surgery forgranted, but 30 years ago Kelman’s approachwas heretical and was met with overt hostilityby the established academic surgical commu-nity. His only research support from 1964 to1970 was an annual grant from the John A.Hartford Foundation. Kelman never receivedresearch support from the National Institutesof Health, and all of his preclinical and clini-cal research was done while he was a full-timepracticing ophthalmologist.

As Figure 2 illustrates, 25 years passedbefore Kelman’s phacoemulsification becamethe definitive technique for removingcataracts. The year 1996 was the first in which97% of all cataract operations in the UnitedStates were done by phacoemulsification onan outpatient basis1. The steep rise in accept-ance of phacoemulsification from 16% in1985 (ref. 12) to 97% in 1996 (ref. 1) was aresult of evolving improvements in surgicaltechniques and equipment. Better micro-scopes, phacoemulsification machines, irri-gation systems, sutureless incisions andintraocular lenses all contributed to increas-ing patient safety and visual acuity.

Impact of Kelman’s vision: seeingbeyond the cataractIn large part because of Kelman’s ingenuity,dedication and inspiration, phacoemulsifica-tion has become not only the most commonbut also the most successful surgical proce-dure in history. Its simplicity has eliminatedmost of the operative and postoperativecomplications of cataract removal and hasprofoundly broadened the number ofpatients whose eyesight can be restored withheightened quality of life.

Kelman’s vision and influence on medi-cine extend beyond the lens of the eye.Among the first of the minimally invasivesurgical techniques, phacoemulsificationstimulated the subsequent development ofother outpatient ‘keyhole’ surgeries, includ-ing removal of the gall bladder, lumpectomyof the breast and repair of vertebral discs.The Kelman phacoemulsification machine isused by neurosurgeons to dissect tumorsfrom the delicate tissues of the brain andspinal cord in children.

Kelman has received considerable recogni-tion for his legendary contributions to medi-cine, including every major award in the fieldsof ophthalmology and cataract surgery. In1994, his peers named him “Ophthalmologistof the Century.” Moreover, in 1992 he wasawarded the National Medal of Technology byPresident George H. Bush, and in 2004 he wasinducted into the National Inventors Hall ofFame, the elite members of which include the likes of Alexander Graham Bell, OrvilleWright, Henry Ford, Enrico Fermi and LeoSzilard.

1. Leaming, D.V. Practice styles and preferences ofASCRS members—2003 survey. J. CataractRefract. Surg. 30, 892–900 (2004).

2. Jaffe, N.S. Cataract Surgery and Its Complications120–122 (C.V. Mosby Co., St. Louis, 1972).

3. Apple, D.J. & Sims, J. Harold Ridley and theinvention of the intraocular lens. Surv. Ophthal.40, 279–292 (1996).

4. Kelman, C.D. Phaco-emulsification and aspira-tion. A new technique of cataract removal. Am. J.Ophthalmol. 64, 23–35 (1967).

5. Kelman, C.D. The history and development of pha-coemulsification. Int. Opthalmol. Clin. 34, 1–12(1994).

6. Kelman, C.D. History of phacoemulsification. inPhacoemulsification—New Technology andClinical Application (ed. Fine, I.H.) 1–16 (SlackInc., Thorofare, New Jersey, USA, 1996).

7. Solomon, R. & Donnenfeld, E.D. Recent advancesand future frontiers in treating age-relatedcataracts. JAMA 290, 248–251 (2003).

8. Kelman, C.D. Through My Eyes: The Story of aSurgeon Who Dared to Take on the Medical World 107–110 (Crown Publishing, New York,1985).

9. Kelman, C.D. Phaco-emulsification and aspira-tion. A progress report. Am. J. Ophthalmol. 67,464–477 (1969).

10. Kelman, C.D. Phaco-emulsification and aspira-tion. A report of 500 consecutive cases. Am. J.Ophthalmol. 75, 764–768 (1973).

11. Kratz, R. From von Graefe to Kelman. A timeline ofophthalmic advances in the 20th century. CataractRefract. Surg. Today 3, 55–56 (2004).

12. Leaming, D.V. Practice styles and preferences ofASCRS members—1985 survey. J. CataractRefract. Surg. 12, 380–384 (1986).

Joseph L. Goldstein is chair of the LaskerAwards Jury and is in the Department ofMolecular Genetics, University of TexasSouthwestern Medical Center, 5323 HarryHines Boulevard, Room L5.238, Dallas, Texas75390-9046, USA.e-mail: joe.goldstein@utsouthwestern.edu

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Figure 2 Rise in use of the phacoemulsificationprocedure for removal of cataracts in the UnitedStates from 1967 to 2003. The data from 1985to 2003 are based on surveys of members of theAmerican Society of Cataract and RefractiveSurgery conducted annually by D.V. Leaming andpublished annually in the Journal of Cataract andRefractive Surgery. For the first survey (1985)and the last survey (2003), see references 12and 1, respectively. The total number of cataractoperations in the United States in 2003 isestimated to be nearly 3 million.

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