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Eye (Lond). 2017 January; 31(1): 161–162.
Published online 2016 October 7. doi:  10.1038/eye.2016.211
PMCID: PMC5233935

Reply to ‘Can photoreceptor loss also account for changes in pupil size following panretinal photocoagulation?'


We thank the authors for showing interest in our study1 and for their valuable contributions.

In our study, we aimed to evaluate the possible changes in pupil size subsequent to panretinal laser photocoagulation (PRP) via Conventional laser and pattern scan laser (PASCAL). We found out that the pupil size increases (according to objective pupillary measurements) following PRP in patients with proliferative diabetic retinopathy (PDR).1 Although we have not known the exact underline mechanism of pupillary size changes, we hypothesize that it may be secondary to damage to short posterior ciliary nerves, which transverse the suprachoroidal space. There are some minor studies in literature that supported our hypothesis.2, 3

The authors pointed out to a good hypothesis that the damaged peripheral retinal photoreceptors following PRP may be a partially mechanism, which explains the increased pupil size after PRP.4 Additional studies are required to find out the exact underline mechanism.

The authors also added that it would be of great benefit if we could clarify whether the untreated eye was also exposed to light during the direct pupillometric measurement and whether anisocoria was observed.4 However, we do not have the pupillometry measurements of non-studied eyes.


The authors declare no conflict of interest.


  • Yilmaz I, Perente I, Saracoglu B, Yazici AT, Taskapili M. Changes in pupil size following panretinal retinal photocoagulation: conventional laser vs pattern scan laser (PASCAL). Eye (Lond) 2016; 30: 1359–1364. [PMC free article] [PubMed]
  • Schiodte SN. Effects of choroidal nerves after panretinal xenon arc and argon laser photocoagulation. Acta Ophthalmol (Copenh) 1984; 62: 244–255. [PubMed]
  • Kaufman PL. Parasympathetic denervation of the ciliary muscle following retinal photocoagulation. Trans Am Ophthal Soc 1990; 88: 513–553. [PMC free article] [PubMed]
  • Najjar RP, Milea D. Can photoreceptor loss also account for changes in pupil size following panretinal photocoagulation? Eye 2017; 31: 161.

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