Radial keratotomy

Radial keratotomy

Radial keratotomy A ten-year follow-up study has found radial keratotomy to be reasonably safe, but unpredictable, in terms of both the short-term and...

201KB Sizes 1 Downloads 148 Views

Radial keratotomy A ten-year follow-up study has found radial keratotomy to be reasonably safe, but unpredictable, in terms of both the short-term and long-term changes in the refractive characteristics of the eye. The findings of the Prospective Evaluation of Radial Keratotomy study’ were based on operations on 693 eyes (374 patients, with operations 1 year apart for those with 2 eyes treated). At baseline, 66% of eyes had an uncorrected acuity of 20/200 or worse, with myopia of -2 to -9 dioptres.’

Baseline spectacle-corrected acuity was 20/25 or better in all the eyes. Ten years after radial keratotomy, 70% of the

patients reported

not

wearing spectacles

lenses for distance vision; 53% of the operated eyes achieved uncorrected Snellen chart visual acuity of 20/20 or better, and 65% had uncorrected acuity of 20/40 or better. 89 eyes that responded insufficiently to initial radial keratotomy underwent repeat operation about 1 year later. 60% of all eyes were within 1-00 D of emmetropia at 10 years, but the 90% prediction interval was 4-42 D wide (±2-21 D). The authors call improvement in this a "major challenge".: or contact

Tackling violence Battered wives need guidance on leaving the home safely, because the time they are most likely to be killed is when they make it clear that they are going, said Jaquelyn Campbell (John Hopkins) at the 24th annual meeting of the Institute of Medicine (Oct 17), on the theme of violence as a health issue. Another speaker, Anne Flitcraft (University of Connecticut), said that physicians ought to become familiar with the signs of domestic violence, and become part of the safety net. The potential for violence in each patient’s life should be assessed across the life-span, with the same enthusiasm with which cholesterol is monitored. Violent episodes should be understood as sentinel events with a grave prognosis. David Satcher (Centers for Disease Control and Prevention) reminded the audience that the risk profile for homicide usually involves arguments between friends or acquaintances, with no intention of robbery or other : felony, but with a gun close at hand. Markku Linnoila, of the National Institute on Alcohol Abuse and Alcoholism, presented data on the correlation of aggressive behaviour with low serotonin turnover in the frontal lobes. Low serotonin activity is also associated with depression, anxiety, and high tolerance for alcohol, benzodiazepine, and anaesthetics. Linnoila says low frontal lobe serotonin activity causes difficulty in impulse control, reflection, and time sequencing of events, and thereby leads to an increased probability of acting out of hostility. Only

1220

An important finding of this study is the continuing hyperopic shift 10 years after the operation. For first-operated eyes, the mean refractive error at 6 months was -0-36 D (myopic), but by 10 years, the mean refractive error was +0’50 D (hyperopic). Furthermore, there was a wide variation in the rate of this long-term change; 43% of eyes shifted by more than 1-00 D, and 3-6% shifted by more than 3-00 D. The only predictive factor for the rate of long-term hyperopic shift was the length of the incisions, and that accounted for only 5% of the variance. The shift slowed 2 years post-keratotomy, but then showed no signs of stopping at 10 years. This long-term hyperopic shift is not seen in unoperated eyes (47 unoperated eyes in the study became 0-65 D more myopic). It is age-related presbyopia, a loss of the ability to accommodate, which usually necessitates corrective lenses for near vision. Although 70% of patients required no distance correction at 10 years, only 40% required neither distance nor near correction, and 3% required both distance and near correction. Patients with a significant hyperopic shift require reading glasses earlier than they otherwise would have. : The authors described the safety level

of the operation as "reasonable", but noted a decrease in spectacle-corrected acuity of at least one line on a Snellen chart in 18% of eyes; 12 eyes lost two to three lines. Because most of the eyes that lost acuity started out better than 20/20 (corrected), no eyes ended up worse than 20/30 (corrected). According to Dr Penny Asbell, the principal investigator at the Mount Sinai PERK Centre in New York, aspects of image quality not assessed in this study remain an issue for some patients. Flare, for instance, has very little effect on acuity when a black-and-white chart is viewed in a darkened room, but can seriously reduce the quality of vision when a lowcontrast subject is seen in bright light.

minority of people with low serotonin actually act aggressively, so this chemical is only one of many factors. To interrupt the cycle by which chil-

Coordination of anticancer measures in France

a

a great many people are willing risk a small chance of some degradation of vision in return for a good chance that they will not have to wear spectacles all the time.

Evidently, to

Paul M Rowe 1

Waring GO III, Lynn MJ, McDonnell PJ, and the PERK Study Group. Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study 10 Years After Surgery. Arch Ophthalmol 1994; 112: 1298-1308.

the

A report from the Inspectorate General of Social Affairs is highly critical of French anticancer policy and calls on the government to act. The document pinpoints dysfunction and incoherence and condemns in particular the failure to specify an overall policy, an undemanding attitude to the care system, and an absence of individuals clearly identified as carrying responsibility. It also declares that early detection of cancer is still getting too little priority. In terms of predefined goals and coordination of resources, say the authors, policy against cancer is non-existent-in striking contrast to the well-organised campaign against AIDS. The main reason, they say, is that the twenty cancer centres that ought to operate a policy have little room for manoeuvre, and that public and private establishments that look after cancer patients are competing rather than cooperating. The report suggests that the cancer centres should consider adopting a system akin to that in the UK, with its formal training programme for oncologists. To deal with the deficiencies, health minister Philippe Douste-Blazy has announced the imminent creation of a national council to coordinate the various aspects of an anticancer strategy, while the government strives in other ways to ensure coordination of national programmes for prevention and detection.

Paul M Rowe

Jean-Yves Nau

dren and adolescents who witness violence in their communities often go on to become victims and perpetrators of violence, officers in the New Haven police department get personally involved in the lives of neighbourhood youths. Steven Marans of Yale runs a programme that provides the police with training in psychology, and liaison with mental health professionals to whom children can be referred. This Child Development and Community Policing Program is funded by private and public sources, including the US Justice Department. Several other cities are signing onto the programme. Secretary of Health and Human Services Donna E Shalala spoke about the need for a comprehensive approach to the problem of violence, and touted the recently passed crime bill as providing an appropriate mix of law enforcement, social programmes, and research. Asked when there would be enough money for research, she answered that there will never be "enough" money, but the administration is trying to get stability in research funding. Asked how to cope constructively with the political sensitivity of research on the biological component of impulsive behaviour, she answered that we are protected from such criticism by having a

comprehensive approach to violence, on grounds that scientifically we ought not to ignore any direction of inquiry.