Pupillary shapes in response to electrical stimulation of the sclera of peripheral cornea in cats and porcines

Hirohara, Yoko, Mihashi, Toshifumi, Miyoshi, Tomomitsu, Miyagawa, Suguru, Kanda, Hiroyuki, Sawai, Hajime, Fujikado, Takashi, Drew, Thomas and Wolffsohn, James Stuart (2015). Pupillary shapes in response to electrical stimulation of the sclera of peripheral cornea in cats and porcines. Investigative Ophthalmology and Visual Science, 56 (7), p. 3374.


Purpose: We have reported that the changes in the pupillary shape in response to electrical stimulation of the branches of the ciliary nerves in cats. (Miyagawa et al. PLoS One, 2014). This study investigates the changes in the pupillary shapes in response to electrical stimulations of the sclera of peripheral cornea in cats and porcines. Methods: Two enucleated eyes of two cats and three enucleated porcine eyes were studied. Trains of biphasic pulses (current, 3 mA; duration, 2 ms/phase; frequency, 40 Hz) were applied using a tungsten electrode (0.3mm diameter). The stimulation was performed at every 45 degree over the entire circular region on the sclera near the cornea. The pupillary images were recorded before and 4 s (cat) and 10 s (pig) after the stimulation and the change in the pupil diameter (Δr) was quantified. The pupillary images were obtained with a custom-built compact wavefront aberrometer (Uday et al. J Cataract Refract Surg, 2013). Results: In a cat eye, the pupil was dilated by the electrical stimulation at six out of eight orientations (before stimulation pupil diameter r=10.10±0.49 mm, Δr=0.33±0.12 mm). The pupil dilated only toward the electrode (relative eccentricity of the pupil center to the pupil diameter change amount rdec=1.15±0.28). In the porcine eyes, the pupils were constricted by the electrical stimulations at the temporal and nasal orientations (r=10.04±0.57 mm, Δr=1.52±0.70 mm). The pupils contracted symmetrically (rdec=0.30±0.12). Conclusions: With electrical stimulation in the sclera of the peripheral cornea, asymmetric mydriasis in cat eyes and symmetrical miosis in porcine eyes were observed. Under the assumption that the electrical stimulation stimulated both muscles that contribute to the pupil control, our hypothesis proposed here is that the pupil dilator is stronger than the pupil sphincter in cat, and pupil sphincter is stronger than pupil dilator in porcine.

Divisions: Life & Health Sciences > Optometry
Life & Health Sciences > Ophthalmic Research Group
Life & Health Sciences
Life & Health Sciences > Vision, Hearing and Language
Additional Information: Annual Meeting of the Association-for-Research-in-Vision-and-Ophthalmology (ARVO)
Full Text Link: http://iovs.arv ... ticleid=2333235
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Published Date: 2015-06
Authors: Hirohara, Yoko
Mihashi, Toshifumi
Miyoshi, Tomomitsu
Miyagawa, Suguru
Kanda, Hiroyuki
Sawai, Hajime
Fujikado, Takashi
Drew, Thomas
Wolffsohn, James Stuart ( 0000-0003-4673-8927)

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