Factors Influencing Central Lamina Cribrosa Depth: A Multicenter Study

Abstract

PurposeTo quantify the influence of ocular and demographic factors on central laminar depth (LD) in healthy participants.MethodsA total of 362 normal subjects underwent optical coherence tomography (OCT) enhanced depth imaging of the optic nerve head (ONH) with a 24 radial B-scan pattern aligned to the fovea–to–Bruch's membrane opening (BMO) axis. BMO, anterior lamina, anterior scleral canal opening (ASCO), Bruch's membrane (BM), and the peripapillary scleral surface were manually segmented. The extent of laminar segmentation was quantified within 72 ASCO subsectors. Central LD was quantified relative to four reference planes: BMO, ASCO, BM, and scleral. The effects of age, sex, ethnicity, IOP, BMO area, ASCO area, and axial length on LD were assessed.ResultsLaminar visibility was most consistent within the central ASCO (median 89%, range, 69%–95%). LDBMO and LDBM were significantly shallower in eyes with greater age, BMO area, and axial length and in females. LDASCO was shallower in eyes with greater ASCO area and axial length and in European and Hispanic descent compared to African descent eyes. LDSclera behaved similarly, but was not associated with axial length. BMO and ASCO area were not different between African descent and European descent eyes.ConclusionsCentral LD was deeper in African descent eyes and influenced least by age, axial length, and sex, but more by ASCO area, when measured relative to the ASCO and sclera. However, the magnitude of these effects for all four reference planes was small, and their clinical importance in the detection of glaucoma and its progression remains to be determined.

OCT-Detected Optic Nerve Head Neural Canal Direction, Obliqueness, and Minimum Cross-Sectional Area in Healthy Eyes

“…our methods of data acquisition have been published. [28][29][30] We use the term ONH to refer to the tissues that are contained within the scleral canal and those immediately adjacent to it (ie, the peripapillary sclera, choroid, and retina as well as the immediate retrolaminar optic nerve).…”

“…PARTICIPANTS: A total of 362 healthy individuals were recruited from 8 centers (5 in the United States, 2 in Germany, and 1 in Canada). [28][29][30] Among these, 246 selfidentified as European descent, 30 47 as Hispanic ethnicity, 47 as African descent, 19 as Asian descent, and 3 as Native American descent participants. Inclusion criteria included age 18 to 90 years; no history of glaucoma; intraocular pressure (IOP) < _ 21 mm Hg; best corrected visual acuity > _ 20/40; refraction less than 66.00 diopter (D) sphere and 62.00 D cylinder; Glaucoma Hemifield Test and mean deviation within normal limits.…”

“…Our strategy for OCT ONH image manual segmentation has been described previously (Figure 1). 28,29 Raw OCT volumes were exported from the device and imported into custom 3D visualization and segmentation software (ATL 3D Suite). 35 ONH and peripapillary landmarks were manually segmented in each radial B-scan, and the ONH was reconstructed 3-dimensionally.…”

“…Segmented landmarks included the internal limiting membrane, posterior surface of the RNFL, posterior surface of Bruch's membrane/retinal pigment epithelium complex, BMO, neural canal wall, anterior scleral surface, and the ASCO (segmented on each side of the canal by visually projecting the plane of the peripapillary anterior scleral surface through the neural canal wall and marking their intersection). 28,29 All manual segmentations were performed by observers at the Optic Nerve Head Research Laboratory, Devers Eye Institute.…”

Optical coherence tomography evaluation of the optic nerve head neuro‐retinal rim in glaucoma

“…This allows specific anatomical structures deeper within the optic nerve head to be identified with high precision and accuracy. These capabilities should ultimately solve both the reference plane and the disc margin problems by enabling those definitions to be based on direct visualisation of specific anatomic entities, such as the Bruch's membrane opening (BMO), the anterior scleral surface and/or the anterior scleral canal opening …”