Comparison of the anterior lamina cribrosa insertion in patients with open angle glaucoma and healthy subjects

Abstract

 

Purpose

 

To determine whether the anterior lamina cribrosa insertion (ALI) is located more posteriorly in open angle glaucoma (OAG) patients than in healthy subjects using swept-source optical coherence tomography (SS-OCT).

 

Methods

 

Prospectively, 58 eyes with OAG having inferotemporal wedge shaped retinal nerve fiber layer defect (MD: -4.25 ± 3.55) and 63 healthy eyes were included. Optic disc was imaged by SS-OCT using 12 radial line B-scans centered on the optic disc, each scan at an every half clock hour meridian. ALI depth was assessed at 13 meridians (inferior-temporal-superior) by measuring 2 parameters: 1) ALI position (ALIP) which was defined as the lineal distance from the anterior scleral edge to the ALI, 2) marginal lamina cribrosa depth (MLCD) which was defined as the perpendicular distance from the anterior scleral opening plane to the anterior lamina cribrosa surface at the location of the anterior scleral edge. The two parameters were compared between OAG and healthy eyes at the corresponding meridian.

 

Results

 

ALIP was significantly greater in OAG patients at 6.5 and 7 o’clock position (6.5 o’clock: 243 ± 68 μm vs. 205 ± 58 μm, p = 0.002; 7 o’clock: 229 ± 75 μm vs. 176 ± 61 μm, p < 0.001). MLCD was significantly greater in OAG patients at 6 to 7 o’clock and 10.5 o’clock position (6 o’clock: 243 ± 75 μm vs. 186 ± 50 μm, p < 0.001; 6.5 o’clock: 265 ± 88μm vs. 195 ± 53 μm, p < 0.001; 7 o’clock: 248 ± 82 μm vs. 171 ± 59 μm, p < 0.001; 10.5 o’clock: 235 ± 95 μm vs. 182 ± 73 μm, p = 0.001). Baseline intraocular pressure was significantly associated with greater ALIP at 7 o’clock (p = 0.009) and MLCP at 6.5 (p = 0.036) to 7 o’clock (p = 0.003). Age was significantly associated with greater MLCP at 6 o’clock (p = 0.024).

 

Conclusions

 

ALI is displaced posteriorly in eyes with OAG compared with healthy eyes, which supports that posterior migration of the lamina cribrosa is a component of optic disc remodeling in glaucoma.

 

 

Figure 1. A. 12 radial scans centered on the optic disc. B. Manual delineation of lamina cribrosa and sclera. C. Measurement of ALIP along the scleral canal. D. Measurement of MLCD perpendicular to the scleral opening plane.

 

 

Figure 2. SS-OCT B-scan image of Control (A) and OAG (B) at 7 o’clock meridian. C, D. Manually delineated images of A and B, respectively (yellow lines). Both ALIP (red line) and MLCD (blue line) are increased in OAG (D) than in control (C).

 

Keywords: 577 lamina cribrosa • 550 imaging/image analysis: clinical • 495 depth