Sir,
First and foremost, I must Congratulate you on your editorial, “Pediatric eye screening, Why, when and How.” It is crisp, well-written, and thought-provoking.[1] As to why screening is needed, there can be no doubt, as pediatric screening can be vision and at times a life-saving method.
Regarding when or what age pediatric screening should be done, there are many issues that need careful analysis. Refractive error, strabismus, anisometropia, and cataract are strongly amblyopiogenic in the first few years of life. Timely diagnosis and treatment of these conditions may prevent amblyopia. (It is a debatable issue.) Theoretically at least, timely diagnosis and treatment of these amblyopiogenic conditions is also important, because cortical visual development continues postnatally till the age of 36 months. Cortical plasticity is the age at which the cortical circuitry can be modified to suit the rapidly altering visual experience, as happens when the interpapillary distance increases as the child grows. The most important period is between 4 and 36 months and after that the plasticity rapidly decreases, although a reduced cortical plasticity persists up to adult life. These four factors mentioned above interfere with cortical visual circuitry, leading to reduced visual acuity and stereo acuity, that is, amblyopia.
The next question as to when we need to screen these children, to prevent amblyopia in them, can be easily answered keeping in mind the discussion above. It is before the age of 36 months and not at the school-going age when the amblyopia would be well-established. This is where we need well-conducted, large-scale, long-term population-based studies. There are not many studies that clearly show the efficacy of visual screening, prior to the age of 36 months. There are no long-term prospective studies that show a reduced incidence of amblyopia in a group of children who were examined and treated below the age of 36 months, compared with those who did not undergo screening prior to 36 months of age! But we must keep in mind that the density of amblyopia is higher, the lower the age at which monocular deprivation occurs and the longer the duration of deprivation, due to the factors mentioned above. What this means to a clinician is diagnose and treat Amblyopia as early as possible! Hence waiting longer will not help.
In addition, one has to keep in mind the cost-effectiveness of such a screening procedure prior to the age of 36 months! Considering that every day 50,000 children are born in India, it is going to be a humongous task! It needs a lot of money and skilled man power, which our country seriously lacks.
All India Ophthalmological Society has a Pediatric ophthalmologist task force that will surely look into this screening aspect, prior to the age of 36 months.
As to who should be screening and where and how, we do not have a concrete answer at all, as of now. But your editorial has made us all take a few unsteady steps in the right direction. Your editorial was timely and thought-provoking.
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Conflicts of interest
There are no conflicts of interest.
Reference
1. Honavar SG. Pediatric eye screening – why, when, and how Indian J Ophthalmol. 2018;66:889–92
