Response to comments on: Changes in pattern electroretinogram after application of 0.01% atropine eye drops.

Dear Sir,

We are thankful to Jethani et al.[1] for their interest in our paper.[2] The reason for their “inability” to detect the changes in the pattern electroretinogram (PERG) following the instillations of 0.01% atropine eye drops may be due to a simple explanation.

Skin electrodes, used by Jethani et al., measure more than 100 μv and pick up more neural noise. The machine then processes the signal by complex averaging of the signals changing the actual result. DTL electrodes, used by us, are applied to the eye and capture very small and noise-free electrical signals ranging from just 1.0 μv to 20 μv. We caution the clinicians against the use of skin electrodes in obtaining the PERG, which is against the ISCEV standards.[3] The results obtained using different electrodes on different machines are not comparable.

The PERG changes with 0.01% atropine eye drops reported by us were real. However, it was an experimental condition where 4 drops of 0.01% atropine were applied in succession. It is possible that when only one drop of 0.01% atropine eye drops is applied once at night, no predictable changes might be recorded on PERG.[4]

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Conflicts of interest

There are no conflicts of interest.