Can photoreceptor loss also account for changes in pupil size following panretinal photocoagulation?

Pupillary light responses in type 1 and type 2 diabetics with and without retinopathy

“…; Messias et al. ; Najjar & Milea ). Moreover, three of the patients in the 2019 study had a diabetic macular oedema, which could also have impacted on their results (Park et al.…”

“…Another important factor, which could affect the PIPR in Park's studies, is the effect of the treatments with anti-VEGF or focal laser. Even though they showed reduced melanopsin function after excluding patients with anti-VEGF in the 2017 study, the remaining patients in that particular group had a history of laser treatment, which is known to affect retinal photoreceptors (Ogden et al 1976;Hoshino 1995;Kim et al 2012;Messias et al 2012;Najjar & Milea 2017). Moreover, three of the patients in the 2019 study had a diabetic macular oedema, which could also have impacted on their results (Park et al 2019).…”

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

“…3 The extent of retinal damage generated by PRP is dependent upon the laser beam's diameter, power, and duration. 4 Even though the exact power of the used beams was not specified by the authors, it is conceivable that a light-intensity photocoagulation such as the one they have used, especially with conventional PRP, might have inflicted structural and functional damage not only to the photoreceptors, retinal pigment epithelium, and choroid, but also to the retinal nerve fiber layer and inner retina as well, 4,5 possibly altering the photoreceptive and integrative capabilities of ipRGCs and increasing pupil size under various conditions of illumination. Furthermore, it would be of great benefit if the authors could clarify whether the non-studied/untreated eye was also exposed to light during the direct pupillometric measurement and whether anisocoria was observed.…”

“…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.…”