UMMS Affiliation

Department of Ophthalmology and Visual Sciences

Publication Date


Document Type



Eye Diseases | Ophthalmology | Therapeutics


Purpose: To assess potential vascular, structural, and functional changes to the macula in patients with keratoconus that underwent ultraviolet A (UVA)-riboflavin-mediated corneal collagen cross-linking (CXL) therapy.

Patients and methods: Seventeen eyes from 17 patients of age 16 years or older with keratoconus undergoing CXL treatment were studied. The same eye served as its own control (before CXL vs after CXL). Eyes were evaluated in terms of best-corrected visual acuity (BCVA), refractive error, intraocular pressure, Amsler grid, retinography, fluorescein angiography, autofluorescence, and spectral domain optical coherence tomography (SD-OCT) prior to CXL and 7 and 30 days after treatment. Multifocal electroretinography (mfERG) was recorded prior to and 7 days after CXL.

Results: Mean (SD) BCVA by logMAR chart was 0.47 (+/-0.12) pre-CXL, 0.55 (+/-0.15) 7 days post-CXL (P=0.57), and 0.46 (+/-0.10) 30 days post-CXL (P=0.87). Mean (SD) SD-OCT central macular thickness (microm) was 253.62 (+/-20.9) pre-CXL, 260.5 (+/-18.7) 7 days post-CXL (P=0.48), and 256.44 (+/-21.6) 30 days post-CXL (P=0.69). In 12 eyes, mfERG revealed a statistically significant increase (P=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 (P=0.027). Furthermore, nine patients experienced a significant decrease in P1 amplitudes of rings 1 (P=0.0014), 2 (P=0.0029), 3 (P=0.0037), 4 (P=0.0014), and 5 (P=0.0012) from pre-CXL to 7 days post-CXL.

Conclusion: 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.


UVA, crosslinking, keratoconus, light damage, multifocal electroretinogram, phototoxicity

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DOI of Published Version



Clin Ophthalmol. 2018 Sep 17;12:1801-1807. doi: 10.2147/OPTH.S176025. eCollection 2018. Link to article on publisher's site

Journal/Book/Conference Title

Clinical ophthalmology (Auckland, N.Z.)

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Creative Commons License

Creative Commons Attribution-Noncommercial 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial 3.0 License



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