Laser eye surgery was supposed to be the great savior for all glasses-wearers, and was science’s answer to most of the common sight problems. But, already, the hype and hope are giving way to growing concerns over the safety and effectiveness of the various techniques, and patients are proving to be somewhat elusive just as the surgery is being offered on every high street.
In the US, a growing number of consumers is questioning the procedure, and its popularity is apparently waning. At its peak in 2000, 1.42 million Americans underwent the surgery, but figures for the following two years saw a significant drop to 1.31 million in 2001 and 1.15 million in 2002. Profits and share prices of the medical chains performing the operation tumbled as a result (International Herald Tribune, 31 January 2003).
Patients’ concerns are well placed. Researchers at the New Jersey Medical School discovered that as many as one in five of the patients in their study of 1306 patients needed to undergo retreatment to repair or enhance the first one (Ophthalmology, 2003; 110: 748-54).
One of the major concerns of ophthalmologists is the sudden loss of contrast sensitivity – the ability to distinguish objects in poor light – after surgery. This problem surfaced in 1996 when researchers at Tubingen University in Germany reported that three-quarters of the patients who had undergone photorefractive keratectomy (PRK) surgery for myopia over the previous 10 years had such poor contrast sensitivity that they failed federal German night vision standards (ASCRS Symposium, June 1996).
The London Center for Refractive Surgery has reported similar problems. After hearing of the German findings, the centre recalled all patients treated with an Excimer laser and found that 56 per cent (36 of 54 patients) also had greatly reduced contrast sensitivity (Lancet, 2003; 361: 1225-6).
This loss of sensitivity appears to be permanent and untreatable, says Dr William Jory, consultant ophthalmologist at the London Center for Refractive Surgery.
These findings have been supported by a further German study (ESCRS, Brussels, 2000) and one from Canada (Can J Ophthalmol, 2000; 35: 192-203). The Canadian federal government in Ottawa has now advised all provincial governments to test patients’ night vision after surgery before a driver’s licence is issued.
Advocates of laser eye surgery argue that many of these safety issues relate to the PRK technique, which has since been superseded by LASEK (laser subepithelial keratomileusis), a modification of PRK, and by LASIK (laser in situ keratomileusis), now probably the most popular form of laser eye surgery (Semin Ophthalmol, 2003; 18: 2-10).
With PRK, the surgeon applies the laser beam directly to the cornea (the transparent tissue covering the front of the eye), and ‘shaves’ and reshapes it. LASIK uses a special knife to lift a flap of tissue from the surface of the cornea to reveal the corneal bed (stroma). The laser works on this tissue, then the flap is replaced. The LASEK technique detaches the outermost layer (epithelium) of the cornea, and reshapes the corneal surface with the laser. The epithelium is then returned to its normal position.
There has been a range of concerns about the PRK technique, but one that is rarely aired is the possibility of postoperative infection. One study reviewed the records of 12 PRK patients who developed infectious keratitis, which can result in corneal ulceration. The researchers recommended that just-in-case antibiotics be given to all PRK patients before surgery (Ophthalmology, 2003; 110: 743-7).
Contrast sensitivity is also a major concern for PRK patients. Researchers at Moorfield’s Eye Hospital in London reported that 30 per cent of its PRK patients suffered a loss of contrast sensitivity within two years of surgery (Refractive Surgery Symposium, London 2001) – and the same symposium heard that half of all LASIK patients suffered a similar loss, one year after surgery.
The LASIK technique can cause the cornea to weaken in up to 40 per cent of all cases (Lancet, 2003; 361: 1225-6) and, sometimes, the weakened cornea resumes its original shape – so the myopia returns.
One study reported on a variety of complications following LASIK surgery. Of the 24 cases, 13 of the complications occurred during the procedure, and the rest afterwards. The technique, the researchers concluded, could result in serious complications that can lead to visual loss (Eur J Ophthalmol, 2003; 13: 139-45).
Patients may also have to go through a second, corrective operation. In one study of 1306 LASIK patients, over 10 per cent had to have a second operation, a likelihood that increases with age, the degree of initial correction and the extent of astigmatism (Ophthalmology, 2003; 110: 748-54).
As with PRK, postoperative infection is also a concern for the LASIK patient. One study found that keratitis could occur up to 450 days after surgery, and was serious enough to threaten vision (Ophthalmology, 2003; 110: 503-10).
The US Food and Drug Administration (FDA) is equally unsure of the LASIK technique. According to its website (www. fda.gov), LASIK is ‘an option for risk takers’.
LASEK is a newer technique, so there are fewer studies into its efficacy and safety. However, one study from Japan urges caution. After studying the progress of 42 LASEK patients, the researchers reported postoperative complications such as pain, delayed recovery of visual sharpness and corneal haze (Nippon Ganka Gakkai Zasshi, 2003; 107: 249-56).
Compared with PRK, LASEK may result in less discomfort in the early postoperative period, faster visual recovery and less haze, but these claims, made by LASEK proponents, need to be vindicated in long-term trials, say researchers at the University of Washington (Semin Ophthalmol, 2003; 18: 2-10).
With more and more ‘walk-in’ laser-surgery centers opening up, the emphasis is on the benefits; very few mention the possible risks either in their advertisements or during the face-to-face consultations before the operation.
Some patients whose lives have been ruined by eye surgery have taken on the task of providing a health warning to potential patients, and also provide help to those already affected. The Surgical Eyes Foundation (website: http://www.surgicaleyes.org) is a US-based support group for people with ‘longer-term complications from refractive surgery’. Their aim is ‘to restore quality of life to the thousands who suffer from complications of . . . refractive surgeries’.
Unrealistic expectations, or perhaps expectations that have been put in the patient’s mind by advertisements or during the preoperative discussions, could be at the heart of the issue. Even if you are among those who suffer no reactions or complications after surgery, you are still likely to need to wear glasses for some tasks, eye surgeon David Gartry told the BBC News (26 May 2003).
Quality of treatment can vary enormously from one clinic to another. Yet this information is rarely, if ever, made available to patients choosing where to have their treatment.
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