First Person

Volume 17 Number 6 / December 2013 MacLachlan and Howland5 published results similar,to ours, showing increase in pupil size throughout childhood. They used a flash-powered isotropic photorefractor to record average pupil diameter on the same group of children throughout a 19-year period. Although they recorded average pupil size between the two eyes, they did not measure anisocoria. Our study of 1,306 children shows that pupil size increases through childhood, beginning to level off around age 10 years, and that 19.1% of children in this clinical population have visibly noticeable anisocoria of .0.4 mm,6 while 2.3% have anisocoria of $1.0 mm. This indicates a fairly high prevalence of anisocoria in children. Sex and laterality were not statistically significant. Magnitude of anisocoria appeared to increase after 11 years of age; however, our sample size was small for ages 16-17 years. This study is limited by the comparatively small number of subjects aged 12-17 years. Other possible limitations of this study include lack of dark adaptation, although Cetinkaya and colleagues7 reported that dark adaptation is not a prerequisite for photoscreening and that mean pupillary diameter was actually decreased after 10 minutes of dark adaptation. In our study, photoscreening was performed in a darkened screening room. Although it would be expected for there to be slight variability in ambient lighting, there is no reason to expect that such variability would negatively affect this study. Ettinger and

Silbert et al

colleagues8 showed that a tenfold change in luminance caused no more than a 1 mm change in pupil size. This study was performed in a clinical pediatric ophthalmology practice, and patients may not reflect the general pediatric population. Finally, there may be some selection bias, of which we are unaware. References 1. Taylor WR, Chen JW, Meltzer H, et al. Quantitative pupillometry, a new technology: normative data and preliminary observations in patients with acute head injury. J Neurosurg 2003;98:205-13. 2. Usui S, Stark L. Sensory and motor mechanisms interact to control amplitude of pupil noise. Vision Res 1977;18:505-7. 3. Bradley JC, Bentley KC, Mughal AI, Bodhireddy H, Brown SM. Darkadapted pupil diameter as a function of age measured with the NeurOptics pupillometer. J Refract Surg 2010;27:1-6. 4. Boev AN, Fountas KN, Karampelas I. Quantitative pupillometry: normative data in healthy pediatric volunteers. J Neurosurg 2005; 103:496-500. 5. MacLachlan C, Howland HC. Normal values and standard deviations for pupil diameter and interpupillary distance in subjects aged 1 month to 19 years. Ophthalmic Physiol Opt 2002;22:175-82. 6. Lowenfeld IE. “Simple central” anisocoria: a common condition seldom recognized. Trans Am Acad Ophthalmol Otolaryngol 1977; 83:832. 7. Cetinkaya A, Oto S, Aydin P. The impact of dark adaptation on photoscreening. J AAPOS 2002;6:315-18. 8. Ettinger E, Wyatt H, London R. Anisocoria: variation and clinical observation with different conditions of illumination and accommodation. Invest Opthalmol Vis Sci 1991;32:501-9.

First Person I normally send my patients out to an “eyedrops” room for their cycloplegic refraction. They are called in 3 times over a period of 10 minutes. Yesterday, 2-year-old Benjamin objected and, every time he was called, protested vehemently (to the amusement of all in the waiting area), “That’s not my name! That’s not my name!” Contributed by Pauline Cheong, MBBS, FRCS, Singapore

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