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Kritchai Vutipongsatorn, Takeshi Yoshida, Xuejiao Li, Kejia Cao, Kyoko Ohno-Matsui; Constructing Murine Model of Posterior Staphyloma Through Targeted Disruption of Bruch’s Membrane. Invest. Ophthalmol. Vis. Sci. 2019;60(9):5875.
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© ARVO (1962-2015); The Authors (2016-present)
Pathologic myopia is a leading cause of visual impairment and blindness especially in East Asia. Its key feature, posterior staphyloma, remains poorly understood with no appropriate animal models and effective treatments. Recent studies report that Bruch’s membrane (BM) is extremely thinned or lost along staphyloma edges. Since posterior staphyloma is predominantly seen in elongated globes, we hypothesise that BM defects and globe elongation would contribute to its formation.
Laser photocoagulation was used to disrupt BM in a circular manner around optic disc. C57BL/6JJc1 mice were divided into three groups. Group 1 (n=4) did not receive photocoagulation. Groups 2 (n=6) and 3 (n=7) received 50 and 100 mW photocoagulation respectively. Animals’ right eyes were then sutured shut for three weeks to induce axial elongation before histology sections at optic nerve head were obtained.
BM was markedly disrupted with 100 mW, but not with 50 mW photocoagulation. Elongation occurred in all lid-sutured eyes, but was only statistically significant in the 100 mW group (+4.57%, p=0.028). A sub-analysis showed that significant result came from eyes that remained completely shut for three weeks (p=0.029). An obvious outpouching, restricted by areas of BM defects, was seen in lid-sutured eyes from 100 mW group (Figure 1) compared to control eyes (Figure 2). However, this staphyloma-like deformity lacked characteristic thinning of tissues seen in patients with pathologic myopia.
Appearance of staphyloma-like deformity in experimental globes suggests that BM disruption and globe elongation may play a role in posterior staphyloma formation, providing potential targets for future therapies. However, more research is needed to mimic the characteristic eye wall thinning seen in patients.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
Figure 1 Histology image (x40 magnification) of lid-sutured eye that received 100 mW photocoagulation. Red arrows mark areas where BM is markedly thinned or absent (BM is difficult to visualise at x40, but we have images at x200 magnification to confirm the defect). An apparent posterior protrusion, restrcicted by BM defects, is seen.
Figure 2 Histology image of eye that did not receive photocoagulation and lid-suturing showing normal histology.
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