The scAAV viral vector provides prolonged and safe transduction in the trabecular meshwork of rats and monkeys. The stable expression and safe properties of this vector could facilitate the development of trabecular meshwork drugs for gene therapy for glaucoma.

We injected lentiviral vectors into the eyes of live nonhuman primates to assess potential for glaucoma gene therapy. Anterior chambers of five cynomolgus monkeys were injected with green fluorescent protein (GFP)-encoding feline immunodeficiency viral vectors. The monkeys were monitored for in vivo transgene expression and clinical parameters. Their eyes were harvested 2-15 months postinjection for tissue analyses. All seven eyes injected with 1.0-2.0 x 10(8) transducing units (TU) showed substantial GFP fluorescence in the trabecular meshwork (TM), which was observable even by goniophotographic monitoring for up to 15 months. Only the lowest dose (0.03 x 10(8) TU) failed to result in TM fluorescence detectable in vivo, and five of the eight vector-injected eyes continued to display substantial GFP expression when enucleated eyes were examined at 2, 7, or 15 months postinjection. Some transduced cells were also detected in the iris and ciliary body. Mild, transient postinjection inflammatory responses exceeding that induced by a control saline injection were observed, but vectors did not raise intraocular pressure and were well tolerated. The results demonstrate the first lentiviral vector transduction of the nonhuman primate aqueous humor outflow pathway and support application of the system to human glaucoma gene therapy.

Optical coherence tomography (OCT) is a non-invasive, non-contact imaging technique capable of producing high-resolution images of the retina and optic nerve. These images provide information that is useful for following the progression and/or resolution of posterior segment disease. Rapid advances in OCT technology allow the acquisition of increasingly detailed images, approaching the original goal of providing in vivo histopathology. Increases in scan acquisition speeds and axial resolution enhance the clinical diagnostic value of this modality. Adapting instrumentation designed for use in human patients for use in animals can be challenging. Each species has a unique set of adjustments that need to be made but it is possible to obtain reproducible, high quality OCT images in a variety of animals, including rodents, dogs, cats, pigs and monkeys. Deriving quantitative measurements from OCT instruments is hindered by software algorithm errors in detecting the edges of the distinct retinal layers. These segmentation errors occur in scans of human eyes as well in other species and arise with similar frequency with each of the different OCT instruments. Manual segmentation methods to derive optic nerve head and other structural indices have been developed for several species.

Objective To obtain normative data for the canine cornea and conjunctiva using high-resolution Time- and Fourier-Domain optical coherence tomography (TD-OCT and FD-OCT) and ultrasound pachymetry (USP). Animals One hundred sixty-eight eyes of 133 healthy, young, intact laboratory beagles. Procedures The cornea and conjunctiva of 16 eyes of 8 healthy young intact female intact beagles were imaged using FD-OCT. Corneal thickness was measured with FD-OCT and USP, while corneal and conjunctival epithelial thickness was measured with FD-OCT. The central corneal thickness (CCT) was determined in 152 eyes of 125 healthy young adult intact female (35) and male (90) beagles using TD-OCT. Mixed effects linear regression was used for statistical analysis. Results The CCT was (mean ± standard deviation) 497.54 ± 29.76, 555.49 ± 17.19 and 594.81 ± 33.02 μm as measured by FD-OCT, USP and TD-OCT, respectively. The central, superior paraxial, superior perilimbal corneal epithelial thickness and superior bulbar conjunctival epithelial thickness was 52.38 ± 7.27, 56.96 ± 6.47, 69.06 ± 8.84 and 42.98 ± 6.17 μm, respectively. When comparing techniques used for measuring CCT (USP versus FD-OCT and FD-OCT versus TD-OCT), USP and TD-OCT generated significantly greater values in comparison to FD-OCT (both P < 0.001). For all dogs CCT increased with increasing age and body weight (both P < 0.001) and was higher in intact males versus females using TD-OCT (P = 0.034). Conclusion High-resolution FD-OCT and TD-OCT provide detailed non-invasive evaluation of in vivo canine anterior segment structures. Normative values of the canine cornea and conjunctiva are reported.