Macular phototoxicity after corneal cross-linking

Abstract

Mean (SD) BCVA by logMAR chart was 0.47 (±0.12) pre-CXL, 0.55 (±0.15) 7 days post-CXL (<i>P</i>=0.57), and 0.46 (±0.10) 30 days post-CXL (<i>P</i>=0.87). Mean (SD) SD-OCT central macular thickness (µm) was 253.62 (±20.9) pre-CXL, 260.5 (±18.7) 7 days post-CXL (<i>P</i>=0.48), and 256.44 (±21.6) 30 days post-CXL (<i>P</i>=0.69). In 12 eyes, mfERG revealed a statistically significant increase (<i>P</i>=0.0353) in P1 latency (ms) of ring four from the pre-CXL period (39.45±2.05) to 7 days post-CXL (41.04±1.28) period. Regression analysis showed that the increase in P1 latency was correlated with the increase in central macular thickness (<i>P</i>=0.027). Furthermore, nine patients experienced a significant decrease in P1 amplitudes of rings 1 (<i>P</i>=0.0014), 2 (<i>P</i>=0.0029), 3 (<i>P</i>=0.0037), 4 (<i>P</i>=0.0014), and 5 (<i>P</i>=0.0012) from pre-CXL to 7 days post-CXL. <b>Conclusion:</b> In this pilot study, most of the patients exhibited slight changes in their mfERG parameters and OCT thickness, despite a lack of vascular abnormalities observed on fluorescein angiography/autofluorescence imaging, no alteration in BCVA, and no reports of symptoms. These changes could, therefore, be categorized as a mild subclinical effect of the corneal cross-linking procedure.