Published date: Apr 29 2022

Journal Title: Journal of Ophthalmic and Vision Research

Issue title: April–June 2022, Volume 17, Issue 2

Pages: 196–201

DOI: 10.18502/jovr.v17i2.10790

Yao Wangyao.wang@queensu.caDepartment of Ophthalmology, Queen’s University, Kingston, ON, Canada

Patrick WangSchool of Medicine, Queen’s University, Kingston, ON, Canada

Rachel Y. OhSchool of Medicine, Queen’s University, Kingston, ON, Canada

Timothy RatzlaffDepartment of Ophthalmology, Queen’s University, Kingston, ON, Canada

Jacob RulloDepartment of Ophthalmology, Queen’s University, Kingston, ON, Canada

Sanjay SharmaDepartment of Ophthalmology, Queen’s University, Kingston, ON, Canada

Purpose: This cross-sectional study aimed to compare changes in scleral thickness between eyes injected with repeated anti-vascular endothelial growth factor (anti-VEGF) drugs and fellow injection naive eyes using optical coherence tomography (OCT).

Methods: A total of 79 patients treated with three intravitreal anti-VEGF injections in one eye versus no injections in the fellow eye were included. Anterior segment- OCT measured scleral thickness in the inferotemporal quadrant 4 mm away from the limbus.

Results: Injected eyes had a mean scleral thickness of 588 ± 95 μm versus 618 ± 85 μm in fellow naïve eyes (P < 0.001). Comparing injected eyes to fellow naïve eyes stratified by injection number showed a mean scleral thickness of 585 ± 93 μm versus 615 ± 83 μm in eyes with 3–10 injections (n = 32, P = 0.042); 606 ± 90 μm versus 636 ± 79 μm in eyes with 11–20 injections (n = 24, P = 0.017); and 573 ± 104 μm versus 604 ± 93 μm in eyes with >20 injections (n = 23, P = 0.041). There was no significant correlation between injection number and scleral thickness change (r = –0.07, P = 0.26). When stratified by indication, subjects with retinal vein occlusions showed a statistically significant difference in scleral thickness between injected and fellow naïve eyes (535 ± 94 μm and 598 ± 101 μm, respectively, P = 0.001).

Conclusion: Compared to injection naive eyes, multiple intravitreal injections at the repeated scleral quadrant results in scleral thinning. Consideration of multiple injection sites should be considered to avoid these changes.

Keywords: Intravitreal Injection, Sclera, Macular Degeneration, Macular Edema, Vascular Endothelial Growth Factor

1. Mitchell P, Bandello F, Schmidt-Erfurth U, Lang GE, Massin P, Schlingemann RO, et al. The RESTORE study: ranibizumab monotherapy or combined with laser versus laser monotherapy for diabetic macular edema. Ophthalmology 2011;118:615–625.

2. Zinkernagel MS, Schorno P, Ebneter A, Wolf S. Scleral thinning after repeated intravitreal injections of antivascular endothelial growth factor agents in the same quadrant. Invest Ophthalmol Vis Sci 2015;56:1894– 1900.

3. Wong IY, Koizumi H, Lai WW. Enhanced depth imaging optical coherence tomography. Ophthalmic Surg Lasers Imaging 2011;42:S75–S84.

4. Meek KM, Fullwood NJ. Corneal and scleral collagens–a microscopist’s perspective. Micron 2001;32:261–272.

5. Olsen TW, Aaberg SY, Geroski DH, Edelhauser HF. Human sclera: thickness and surface area. Am J Ophthalmol 1998;125:237–241.

6. Lam A, Sambursky RP, Maguire JI. Measurement of scleral thickness in uveal effusion syndrome. Am J Ophthalmol 2005;140:329–331.

7. Falkenstein IA, Cheng L, Freeman WR. Changes of intraocular pressure after intravitreal injection of bevacizumab (avastin). Retina 2007;27:1044–1047.

8. Zhou Y, Zhou M, Xia S, Jing Q, Gao L. Sustained elevation of intraocular pressure associated with intravitreal administration of anti-vascular endothelial growth factor: a systematic review and meta-analysis. Sci Rep 2016;6:39301.

9. Downs JC, Ensor ME, Bellezza AJ, Thompson HW, Hart RT, Burgoyne CF. Posterior scleral thickness in perfusionfixed normal and early-glaucoma monkey eyes. Invest Ophthalmol Vis Sci 2001;42:3202–3208.

10. Lee SB, Geroski DH, Prausnitz MR, Edelhauser HF. Drug delivery through the sclera: effects of thickness, hydration, and sustained release systems. Exp Eye Res 2004;78:599–607.

11. Kim JE, Mantravadi AV, Hur EY, Covert DJ. Shortterm intraocular pressure changes immediately after intravitreal injections of antivascular endothelial growth factor agents. Am J Ophthalmol 2008;146:930–934.e1.

12. Xu Jia, Juan Yu, Sheng-Hui Liao, Xuan-Chu Duan. Biomechanics of the sclera and effects on intraocular pressure. Int J Ophthalmol 2016;9:1824–1831.

13. Girard MJ, Suh JK, Bottlang M, Burgoyne CF, Downs JC. Biomechanical changes in the sclera of monkey eyes exposed to chronic IOP elevations. Invest Ophthalmol Vis Sci 2011;52:5656–5669.

14. Shelton L, Rada JS. Effects of cyclic mechanical stretch on extracellular matrix synthesis by human scleral fibroblasts. Exp Eye Res 2007;84:314–322.

15. Sergienko NM, Shargorogska I. The scleral rigidity of eyes with different refractions. Graefes Arch Clin Exp Ophthalmol 2012;250:1009–1012.