Letters to the Editor Munchausen Syndrome by Proxy Dear Editor: Munchausen Syndrome cannot be by proxy. This case is a criminal case against a child, and should be reported as such. Munchausen causes injury only to oneself. HESKEL M. HADDAD, MD New York, New York Author reply Dear Editor: I appreciate the fact that Dr Haddad read our case report describing a child with Munchausen syndrome by proxy, who presented with ophthalmologic findings.1 Dr Haddad’s erroneous notion that Munchausen syndrome cannot occur by proxy is exactly why we published the report! All physicians, including ophthalmologists, need to be aware of this condition. The term Munchausen syndrome by proxy was coined by Meadow in 1977.2 The original report stated: “parents who, by falsification, caused their children innumerable harmful hospital procedures—a sort of Munchausen syndrome by proxy.” The crime is committed by a caretaker, usually the mother, who achieves personal attention and/or psychologic gain. Like it or not, the term has achieved acceptable status in the medical literature. A search on PubMed identified 420 articles written about or referring to the topic since 1977. Despite frequent attention in other medical specialties, very little has been published in the ophthalmologic literature. Child abuse claims the lives of 3 children in the United States each day.3 The health care system is the first line of defense against Munchausen syndrome by proxy, and physicians of all types should be aware of this not so rare entity. I appreciate the opportunity once again to raise awareness in the ophthalmologic community about this important condition. DAVID K. COATES, MD Houston, Texas References 1. Baskin DE, Stein F, Coats DK, Paysse EA. Recurrent conjunctivitis as a presentation of Munchausen syndrome by proxy. Ophthalmology 2003;110:1582– 4. 2. Meadow R. Munchausen syndrome by proxy. The hinterland of child abuse. Lancet 1977;2:343–5. 3. Thomas K. Munchausen syndrome by proxy: identification and diagnosis. J Pediatr Nurs 2003;18:174 – 80.
Comparison of Atropine and Patching Treatments Dear Editor: There has been a general impression that strabismus is one of the subspecialities where there is hardly any evidence for what we do. In this context, it is encouraging to read articles like the one published by the Pediatric Eye Disease Investigator Group and the discussion by Dr Kushner.1
The article is very illuminating, as are Dr Kushner’s comments. We wonder if the authors would consider another, more clinical interpretation of their data, one that uses the number needed to treat (NNT).2,3 The concept of the NNT is increasingly being used to make clinical judgements. When we apply this to the results of the article in question, we come up with some interesting possibilities. Although the differences between the patching and treatment groups are not statistically significant, we can see from Table 2 (for all patients) that patching achieved success in 79%, versus 74% with atropine. The resultant NNT for this difference is 20. In other words, we need to treat only 20 patients with patching (instead of atropine) to obtain one additional success. For a condition as common as amblyopia, an NNT of 20 would be considered a reasonably good number to achieve one more success. To continue in this same vein of patching versus atropine, for other races, patching has an NNT of about 7. For age under 5 years, patching has an NNT of 8. For those who have had prior treatment for amblyopia, the NNT is only 5. We do not have the numbers in each group to calculate the confidence interval for these NNTs, but the point estimate is likely to be the best estimate. As far as the duration of patching is concerned, a longer duration did not have a better success rate than a shorter duration. As the allocation of duration was not random but discretionary, could this be because the more severe cases were prescribed a longer duration of patching? For clinicians like us in a developing country, using the NNT ensures that we use reasonable and cost-effective interventions. From the NNT approach, it would seem that patching is superior to atropine. RAVI THOMAS, MD B. VENKATESHWAR RAO, MD Hyderabad, India JYOTI MATALIA, DNB (OPHTHAL) Jamnagar, India References 1. Pediatric Eye Disease Investigator Group. A comparison of atropine and patching treatments for moderate amblyopia by patient age, cause of amblyopia, depth of amblyopia, and other factors. Ophthalmology 2003;110:1632–7, discussion 1637– 8. 2. Thomas R, Padma P, Braganza A, Muliyil J. Assessment of clinical significance: the number needed to treat. Indian J Ophthalmol 1996;44:113–5. 3. Sackett DL, Haynes RB, Guyatt GH, Tugwell P, eds. Clinical Epidemiology. A Basic Science for Clinical Medicine. 2nd ed. Boston: Little, Brown and Co.; 1991:205–9.
Author reply Dear Editor: The concept of number needed to treat (NNT) has potential merit from a public health perspective, particularly in the context of the allocation of limited health care resources. This is a form of analysis that can be applied to the results of a clinical trial to determine the number of patients who