Naturally-occurring myopia and loss of cone function in a sheep model of achromatopsia

Maya Ross, Ron Ofri, Itzhak Aizenberg, Mazen Abu–Siam, Oren Pe’er, Dikla Arad, Alexander Rosov, Elisha Gootwine, Hay Dvir, Hen Honig, Alexey Obolensky, Edward Averbukh, Eyal Banin, Liat Gantz*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Achromatopsia is an inherited retinal disease characterized by loss of cone photoreceptor function. Day blind CNGA3 mutant Improved Awassi sheep provide a large animal model for achromatopsia. This study measured refractive error and axial length parameters of the eye in this model and evaluated chromatic pupillary light reflex (cPLR) testing as a potential screening test for loss of cone function. Twenty-one CNGA3 mutant, Improved Awassi, 12 control Afec-Assaf and 12 control breed-matched wild-type (WT) Awassi sheep were examined using streak retinoscopy and B-mode ocular ultrasonography. Four CNGA3 mutant and four Afec-Assaf control sheep underwent cPLR testing. Statistical tests showed that day-blind sheep are significantly more myopic than both Afec-Assaf and WT Awassi controls. Day-blind sheep had significantly longer vitreous axial length compared to WT Awassi (1.43 ± 0.13 and 1.23 ± 0.06 cm, respectively, p < 0.0002) and no response to bright red light compared to both controls. Lack of response to bright red light is consistent with cone dysfunction, demonstrating that cPLR can be used to diagnose day blindness in sheep. Day-blind sheep were found to exhibit myopia and increased vitreous chamber depth, providing a naturally occurring large animal model of myopia.

Original languageAmerican English
Article number19314
JournalScientific Reports
Issue number1
StatePublished - Dec 2020

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