In vivo analysis of glaucoma-related features within the optic nerve head using enhanced depth imaging optical coherence tomography

Abstract

Structural differences between optic nerve head (ONH) parameters in glaucomatous and non-glaucomatous eyes has been documented, however the association between such parameters in patients with different disease stages is yet to be elucidated. We investigated the relationship between different laminar and prelaminar ONH structures using enhanced depth imaging spectral-domain optical coherence tomography (EDI OCT) in a population with and without glaucoma. In this observational case-control study, we prospectively enrolled healthy individuals and glaucomatous patients with different disease stages. All participants underwent EDI OCT imaging (Heidelberg Engineering). Following ONH parameters were measured on serial vertical B-scans by two examiners masked to patient’s clinical data: lamina cribrosa (LC) and prelaminar neural tissue (PLNT) thicknesses, Bruch’s membrane opening (BMO) and cup depth. Associations between cup depth, and laminar and prelaminar parameters were evaluated controlling for possible confounding factors such as axial length and disc size. Sixty-four eyes of 64 patients were included (30 with glaucoma and 34 controls). Eyes with glaucoma had significantly lower mean LC and PLNT thickness, and greater mean cup depth than controls (p<0.01). There was a significant negative association between PLNT thickness and cup depth in glaucomatous eyes (R2 = 0.158, p = 0.029). In addition, LC thickness correlated significantly with cup depth (R2 = 0.135, p = 0.045). Eyes with thinner LCs presented deeper cups. Overall, cup depth and BMO had the best and LC thickness had the worst intraobserver and interobserver reproducibility grading. In conclusion, significant associations were seen between cup depth, LC and PLNT thickness. Eyes with deeper cups not only had less neural tissue, but also thinner LCs, independent of disc size and axial length. Best reproducibility was found for prelaminar parameters compared to deeper ONH structures.

Structure-function relationships in glaucoma using enhanced depth imaging optical coherence tomography-derived parameters: a cross-sectional observational study

“…Even though these parameters differed significantly between glaucomatous eyes and controls, we did not find any significant structure-functional correlation between LC-derived parameters and VFI values. Our comparative laminar findings are in agreement with most previously published data, as it has been shown that glaucomatous eyes present thinner and deeper LCs than controls [10, 16]. In addition, our structure-functional findings on LC depth corroborate those from Park et al [31], as the authors did not find a significant association between ALD and VFMD values in eyes with different stages of treated glaucoma.…”

“…We adopted the same glaucoma definition we used in previous studies from our group [10–12]. In brief, characteristic glaucomatous optic neuropathy was defined as a vertical cup-to-disc ratio (VCDR) of 0.6 or greater, asymmetry of VCDR of 0.2 or greater between eyes, presence of localized or diffuse peripapillary RNFL (pRNFL) defects, or neuroretinal rim defects in the absence of any other abnormalities that could explain such findings [10–12].…”

“…We adopted the same glaucoma definition we used in previous studies from our group [10–12]. In brief, characteristic glaucomatous optic neuropathy was defined as a vertical cup-to-disc ratio (VCDR) of 0.6 or greater, asymmetry of VCDR of 0.2 or greater between eyes, presence of localized or diffuse peripapillary RNFL (pRNFL) defects, or neuroretinal rim defects in the absence of any other abnormalities that could explain such findings [10–12]. A glaucomatous VF defect in the standard automated perimetry (Humphrey SITA - Standard 24–2, Carl Zeiss Meditec, Dublin, CA) was defined as three or more points in clusters with a probability of less than 5% (excluding those on the edge of the field or directly above and below the blind spot) on the pattern deviation plot, a pattern standard deviation index with a probability of less than 5%, or a glaucoma hemifield test with results outside the normal limits.…”

“…Imaging acquisition has been thoroughly described in a previous study from our group [10]. In short, EDI OCT imaging (SD-OCT; Spectralis, Wavelength: 870 nm; Heidelberg Engineering Co., Heidelberg, Germany) was performed for both eyes of each patient and a serial of vertical B-scan images of the ONH were obtained [13, 14].…”

Evaluation of the lamina cribrosa in patients with diabetes mellitus using enhanced depth imaging spectral-domain optical coherence tomography

“…9 OCT images of eyes with POAG have shown lamina cribrosa deformations such as increased anterior lamina cribrosa depth (ALCD) and decreased lamina cribrosa thickness (LCT). [10][11][12] Diabetes mellitus (DM) is a systemic disease characterized by hyperglycaemia secondary to insulin deficiency or insulin resistance. Increased apoptosis of RGCs and early RGC death have been reported in diabetic eyes.…”