Anterior Ocular Wall Thickness Mapping: Anatomical Adequacy of Fixed-Depth Suprachoroidal Injection

Tao Cai; Li Chen; Yi Lin; Sizhu Chen; You Wang; Junyang Huang; Xiaoyan Ding

doi:10.1016/j.ajo.2026.03.044

Anterior Ocular Wall Thickness Mapping: Anatomical Adequacy of Fixed-Depth Suprachoroidal Injection

Am J Ophthalmol. 2026 Apr 7:288:1-11. doi: 10.1016/j.ajo.2026.03.044. Online ahead of print.

Authors

Tao Cai¹, Li Chen², Yi Lin³, Sizhu Chen², You Wang², Junyang Huang⁴, Xiaoyan Ding⁵

Affiliations

¹ From the School of Medicine (T.C. and X.D.), University of Electronic Science and Technology of China, Chengdu, China.
² Sichuan Eye Medical Center (L.C., S.C., Y.W., J.H., X.D.), Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China.
³ The First School of Clinical Medicine (Y.L.), Southern Medical University, Guangzhou, China; Department of Ophthalmology (Y.L.), General Hospital of Central Theater Command, Wuhan, China.
⁴ Sichuan Eye Medical Center (L.C., S.C., Y.W., J.H., X.D.), Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China. Electronic address: jhuang29@126.com.
⁵ From the School of Medicine (T.C. and X.D.), University of Electronic Science and Technology of China, Chengdu, China; Sichuan Eye Medical Center (L.C., S.C., Y.W., J.H., X.D.), Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China. Electronic address: dingxy75@gmail.com.

PMID: 41956345
DOI: 10.1016/j.ajo.2026.03.044

Abstract

Purpose: To map anterior ocular wall thickness across quadrants and eccentricities in a heterogeneous adult population and to evaluate the anatomical adequacy of fixed-depth suprachoroidal injection strategies currently used in clinical practice.

Design: A cross-sectional observational study.

Methods: A total of 110 eyes from 110 participants (18-75 years; +3.00 to -11.00D) were included. Swept-source anterior segment optical coherence tomography was used to measure central corneal thickness, anterior scleral thickness (AST), conjunctival-tenon capsule thickness, anterior choroidal thickness, anterior conjunctival-scleral thickness, and anterior conjunctival-scleral-choroidal thickness. Measurements were obtained in four quadrants at 0 to 5 mm posterior to the scleral spur at 1-mm intervals. Associations between thickness parameters and demographic, refractive, and anatomical factors were analyzed using mixed-effects models. The frequency of measurements below commonly used suprachoroidal injection depths (900 and 1100 µm) was determined.

Results: Anterior ocular wall thickness exhibited marked spatial variability across quadrants (P < .001), decreasing sharply 1 to 2 mm posterior to the scleral spur before stabilizing. At 4 mm posterior to the scleral spur, all eyes exhibited AST values below 900 µm, and anterior conjunctival-scleral-choroidal thickness was below 900 µm in 63.64% of eyes. AST was independently associated with age and central corneal thickness but showed no association with spherical equivalent or axial length.

Conclusions: Anterior ocular wall thickness varies substantially by quadrant and eccentricity. While fixed-depth needles are clinically safe, understanding this anatomical variation may clarify injection mechanics and support anatomically guided approaches to optimize suprachoroidal drug delivery.