Ophthalmology of Primatomorpha: Lemurs, Tarsiers, Monkeys, Apes, and Relatives

Selected Ophthalmic Tests and Ocular Dimensions in Relation to Activity Pattern in Three Neotropical Nonhuman Primates: Black-Tufted Marmoset (Callithrix Penicillata), Guianan Squirrel Monkey (Saimiri Sciureus), and Azara's Night Monkey (Aotus Azarae Infulatus)

“…This test is called modified STT (mSTT). 22 As previously described in other species with small eyes and small tear production, often the moisture does not reach the folding notch of the tear strip. In such cases, the distance from the notch (0 mm) to the point where the folded tear strip was moistened was measured and reported as a negative number in millimeters.…”

“…In such cases, the distance from the notch (0 mm) to the point where the folded tear strip was moistened was measured and reported as a negative number in millimeters. 22 To measure the corneal touch threshold (CTT), the average of three measurements obtained using a Cochet-Bonnet esthesiometer (Luneau Ophtalmologie, Chartres Cedex 28360, France) was used (Fig. 1D).…”

“…18 Much variation among NHP vision revolves around their activity pattern; globe size, visual acuity, and color vision differ according to their ecological needs. 22 Few studies of NHP have correlated ocular morphological characteristics with visual ecology with a focus on the evolution of vision in primates, analyzing size and form of the eyes as two important evolutionary steps. 10,17 First, nocturnal ancestral predatory species developed large eyes with a wide cornea to enhance luminous capture and thus improve scotopic vision.…”