Corneal hysteresis and anterior segment optical coherence tomography anatomical parameters in primary angle closure suspects

Importance: Corneal hysteresis (CH) is a dynamic marker of structural and functional changes in the cornea associated with intraocular pressure (IOP) and central corneal thickness, but its utility in assessing primary angle closure suspects (PACS) has not been fully elucidated. Background: This study assesses if anterior segment measurements correlate with CH in PACS patients. Design: IRB-approved retrospective review of imaging and records at a university practice. Participants: Sixty-three eyes from 37 patients diagnosed as PACS, without other ocular pathology. Methods: Every eye underwent measurements including: ocular response analyzer (ORA), anterior segment optical coherence tomography (OCT) and a clinical evaluation. ORA measurements were correlated with other anatomic parameters using a mixed effects multivariable linear regression framework. Main Outcome Measures: ORA measurements included: CH, corneal resistance factor, Goldmann IOP (IOP_g) and corneal compensated IOP (IOP_cc). Anterior segment OCT measurements included: central corneal thickness (CCT_OCT), nasal and temporal peripheral corneal thicknesses (PCT1 and PCT2), anterior chamber depth (ACD), nasal angle to temporal angle distance (ATA) and temporal and nasal angle measurements. Clinical measurements included: central corneal thickness via pachymetry, IOP measured by Goldmann applanation, axial length by A-scan ultrasound and spherical equivalent. Results: CH was negatively correlated with IOP_cc, and ACD CH was positively correlated with CCT_OCT, CCT_p, CRF, PCT1 and PCT2. Females were found to have lower CH. In multivariable regression controlling for gender, CCT, PCT, IOP and ACD, no correlation was seen between CH and anatomic measurements. Conclusions and Relevance: CH values in PACS do not correlate with anterior segment anatomy.