Optical coherence tomography characteristics of macular injury from laser spot irradiation

Objective To describe the characteristics of optical coherence tomography (OCT) in patients with macular injury from laser spot irradiation. Methods This was a retrospective study. A total of 16 eyes of 13 patients (11 males and 2 females) were included in the study. Patients were 8-25 years old. Heidelberg OCT was performed on patients who had sustained macular injury because of laser spot surgery irradiation from April 2014 to March 2016 at the Eye Hospital of Wenzhou Medical University. The first visit and follow-up visits took place at the Eye Hospital. Results Five patients were spot irradiated by green laser, 3 patients were spot irradiated by red laser, and the injury to the other 5 patients was unknown. Irradiating time was almost 2 seconds with a follow-up duration from 2 days to 10 months but most irradiation occurred within the span of one week. Visual acuity was 0.08-1.0. Five patients dropped out, and the other 8 patients were followed-up for 5 days to 10 months. One eye was diagnosed with preretinal hemorrhage in the macula, and the OCT of this patient showed a highly reflective mass under the inner limiting membrane of the fovea. One eye was diagnosed with choroidal neovascularization (CNV), and the OCT of this patient showed a high reflection under the uplift of the retinal pigment epithelium (RPE) with neuroepithelium detachment. The other 11 patients were in an early stage of laser spot irradiation injury to the macula. The OCT images of the myoid zone, ellipsoid zone and interdigitation zone of the fovea showed disruptions but the external limiting membrane was good. In the zone of disruptions, highly reflective granules were visible, accompanied or not accompanied by an enhancement of the outer nuclear layer reflection and neuroepithelial detachment. In the late stage, the disruptions in the myoid, ellipsoid and interdigitation zones of the fovea were still evident and the external limiting membrane remained normal. The highly reflective granules had gradually decreased or disappeared, the reflection of the outer nuclear layer was normal, and the neuroepithelial detachment had recovered. No patient had a change in visual acuity between the first and last follow-up visits. Conclusion Laser spot irradiation can lead to macular injury, hemorrhage and CNV in the macula. The OCT images of almost all of the patients showed irreversible disruptions to the myoid, ellipsoid and interdigitation zones of the fovea, a permanent decrease in vision, and a normal external limiting membrane. Key words: Tomography, optical coherence; Laser pointer; Macular injury