Comparison of enhanced depth imaging and high-penetration optical coherence tomography for imaging deep optic nerve head and parapapillary structures

PURPOSE To evaluate and compare the abilities of enhanced depth imaging (EDI) and high-penetration optical coherence tomography (HP-OCT) to visualize the deep optic nerve head (ONH) and deep parapapillary structures. METHODS Horizontal and vertical optic nerve images were obtained using EDI-OCT and HP-OCT, during the same visit, from 24 eyes of 12 patients with glaucoma. Three graders, using a three-point grading system, independently graded the visibility of the deep ONH structures (prelaminar tissue surface, anterior laminar surface, posterior laminar border, and laminar pores) and deep parapapillary structures (intrascleral vessels, cerebrospinal fluid space, and parapapillary choroid). The differences in the visibility scores between the EDI-OCT and the HP-OCT images and among the image locations were analyzed statistically. The agreement in scoring among the graders also was analyzed. RESULTS The visibility of three ONH structures, the anterior laminar surface, posterior laminar border, and laminar pores, was significantly better with EDI-OCT (P = 0.0010, P < 0.0001, and P = 0.0141, respectively). In contrast, the visibility of all parapapillary structures was significantly better with HP-OCT (P < 0.0001, P = 0.0176, and P < 0.0001, respectively). The visibility scores were better in the vertical images compared with the horizontal images and were best in the temporal quadrants. The intergrader agreement was moderate for all parameters examined. CONCLUSION Both EDI-OCT and HP-OCT are useful for evaluating the deep ONH and parapapillary structures. The visibility scores of the deep ONH structures were better with EDI-OCT, in contrast to the better visibility scores of the deep parapapillary structures with HP-OCT. Both systems should be chosen depending on the target tissue to observe.