Early Changes of Ocular Biological Parameters in Rhesus Monkeys After Scleral Cross-linking With Riboflavin/Ultraviolet-A.

Purpose: To evaluate the ocular biological parameter difference between scleral corneal cross-linking (CXL) and control eyes in rhesus monkeys by using a rebound tonometer, A-scan ultrasonography, retinoscopy, optical coherence tomography, and electroretinography (ERG).

Methods: Six rhesus monkeys were used in this study, with ages ranging from 3 to 3.5 years. One eye of each rhesus monkey was randomly selected to receive riboflavin/ultraviolet-A CXL in the temporal quadrant of the equatorial sclera and the contralateral eye served as an intra-individual control. The ocular biological parameters were repeatedly measured in both eyes of the monkeys before scleral CXL and 1 week, 1 month, and 3 months postoperatively.

Results: The intraocular pressure, refractive state, total axial length, and axial dimensions of the anterior chamber, crystalline lens, vitreous chamber, and central corneal thickness were not statistically significantly different between the control and cross-linked specimens at the different time periods (each P > .05). No obvious changes in the waveform of the standard full-field ERGs were observed in the control and cross-linked specimens. There were no statistically significant differences between the control and cross-linked specimens in the dark-adapted 0.01 ERG, the dark-adapted 3.0 ERG, the light-adapted 3.0 ERG, and the amplitudes of the a-wave and b-wave for the different time periods (each P >.05).

Conclusions: The scleral CXL laboratory technique might not significantly affect the ocular biological parameters of the rhesus monkey in the early postoperative period, but long-term effects and histological changes still need to be investigated further. [J Refract Surg. 2019;35(5):333-339.].