Retinoscopy, also known as skiascopy, is an objective method for assessing therefraction of the eye. This method has been used for a long time, both in animalsand human patients. According to the literature, it has been postulated that it is notnecessary to obtain cycloplegia before the examination in lower mammals. Someauthors even mention that it can make the examination more difficult. Therefore itis not recommended.

Skiascopy is used to objectively determine the refractive power of the eye. Except for a Swedish study in 2007, where 93 horses of different breeds and ages were examined with respect to their refractive status, most studies on equine refraction were published about one century ago or more. The objective of this study is to examine the refractive status of healthy warm-blooded trotting horses. Skiascopy was performed in 117 horses in total, aged 3 days to approximately 22 years old. In a pilot study, it was determined whether young horses were able to accommodate or not during skiascopy. The horses in the pilot study were all younger than 14 months. In foals younger than 1,5 months we saw a significant difference in the skiascopy result in the right eyes before and after topical atropine was instilled, but not in the left eye.