June 2023
Volume 64, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2023
Variations in lamina cribrosa insertions into the sclera may contribute to regional differences in neural tissue damage and sensitivity to elevated intraocular pressure
Author Affiliations & Notes
  • Fengting Ji
    University of Pittsburgh Department of Bioengineering, Pittsburgh, Pennsylvania, United States
    University of Pittsburgh Department of Ophthalmology, Pittsburgh, Pennsylvania, United States
  • Po Lam
    University of Pittsburgh Department of Ophthalmology, Pittsburgh, Pennsylvania, United States
  • Bryn L Brazile
    University of Pittsburgh Department of Ophthalmology, Pittsburgh, Pennsylvania, United States
  • Yi Hua
    University of Pittsburgh Department of Ophthalmology, Pittsburgh, Pennsylvania, United States
  • Ian A Sigal
    University of Pittsburgh Department of Ophthalmology, Pittsburgh, Pennsylvania, United States
    University of Pittsburgh Department of Bioengineering, Pittsburgh, Pennsylvania, United States
  • Footnotes
    Commercial Relationships   Fengting Ji None; Po Lam None; Bryn Brazile None; Yi Hua None; Ian Sigal None
  • Footnotes
    Support  National Institutes of Health R01-EY031708, R01-EY023966, P30-EY008098 and T32-EY017271 (Bethesda, MD), the Eye and Ear Foundation (Pittsburgh, PA), and Research to Prevent Blindness (unrestricted grant to UPMC ophthalmology, and Stein innovation award to Sigal IA).
Investigative Ophthalmology & Visual Science June 2023, Vol.64, 61. doi:
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    • Get Citation

      Fengting Ji, Po Lam, Bryn L Brazile, Yi Hua, Ian A Sigal; Variations in lamina cribrosa insertions into the sclera may contribute to regional differences in neural tissue damage and sensitivity to elevated intraocular pressure. Invest. Ophthalmol. Vis. Sci. 2023;64(8):61.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : It is well-established that the lamina cribrosa (LC) depends on the sclera for support. This support must be provided through the LC insertions into the scleral canal. We hypothesized that the LC insertions vary in number and shape over the canal. If so, the differences may help explain the different regional susceptibilities to glaucomatous damage.

Methods : Coronal cryosections through the LC from six healthy monkey eyes were imaged using polarized light microscopy. The images were 3D reconstructed, from which we manually marked all insertions, noting their in-depth position and quadrant (inferior, superior, nasal, temporal). We quantified insertion width and angle, number of insertions and insertion ratio (Fig 1). We used linear mixed effect models to determine if the parameters were associated with in-depth position or quadrant.

Results : Insertions in the most anterior LC were more slanted and significantly narrower, by about 40%, than in the posterior LC (p’s<0.001, Fig 2). There were far many more insertions covering a much larger ratio of the canal wall in the middle LC than in the front and back (p’s<0.001). No significant differences in insertion width, insertion ratio and number of insertions were detected among quadrants. In the nasal quadrant, insertion angles were significantly smaller (p<0.001), but the difference was likely too small to have an important effect.

Conclusions : LC insertions vary substantially and significantly over the canal, with clear patterns from front to back. The sparser, narrower and more slanted insertions of the anterior LC may not provide the robust support afforded by insertions of the middle and posterior LC. These variations may contribute to the progressive deepening of the LC with glaucoma, but appear unlikely to explain quadrant patterns of damage in early glaucoma.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.

 

(A) 3D plot of LC insertions and sclera. (B) 2D diagrams of LC beams (white) and the canal wall (yellow) at two different depths. Insertion ratio was calculated as the ratio between the area of insertions (red) and the area of canal opening (yellow). The left diagram had a larger insertion ratio and a larger number of insertions than the right diagram. Example images illustrating insertions of different width (C) or angle (D).

(A) 3D plot of LC insertions and sclera. (B) 2D diagrams of LC beams (white) and the canal wall (yellow) at two different depths. Insertion ratio was calculated as the ratio between the area of insertions (red) and the area of canal opening (yellow). The left diagram had a larger insertion ratio and a larger number of insertions than the right diagram. Example images illustrating insertions of different width (C) or angle (D).

 

Variations of insertion by depth (top row) and region (bottom row).

Variations of insertion by depth (top row) and region (bottom row).

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