Anterior segment optical coherence tomographic angiography assessment of acute chemical injury

Abstract Purpose To compare routine clinical examination with optical coherence tomography angiography (OCTA) for the assessment of limbal conjunctival ischemia following a chemical burn. Setting Validity analysis Methods We assessed ten participants (15 eyes) with an acute chemical injury. Clinical photographs were used to determine the extent of any limbal conjunctival epithelial defect and ischemia. These were compared with the extent of limbal ischemia identified on OCTA images of the ocular surface. Quantitative and longitudinal analysis using the OCTA software were also performed. Correlations with visual outcome were sought using clinical and OCTA-derived variables. Results The extent of clinically determined limbal ischemia was less than that identified with OCTA (2.3±3.6 clock hours v 5.1±4.2 clock hours, p = 0.003), which in turn was less than the size of limbal conjunctival epithelial defect (7.3±5.1 clock hours, p = 0.03). Longitudinal OCTA analysis showed that mean vessel area increased by 0.2 ±0.1% during the study, corresponding to a rate of vascular recovery of 0.9mm 2 /day. Significant correlations were found between visual outcome at 3 months and limbal conjunctival fluorescein staining (r = 0.67, p = 0.006), and limbal conjunctival ischemia on OCTA (r = 0.76, p = 0.001). Conclusions OCTA can objectively identify and monitor the recovery of limbal ischemia following an acute ocular chemical injury. OCTA confirms that limbal ischemia is usually more extensive than is suggested by clinical examination, and the former is highly correlated with visual outcome. OCTA therefore is a useful tool in the management of ocular chemical injury.