Ocular manifestations of lichen planus: a comparative analysis of tear function, choroidal thickness, and retinal parameters

To assess tear function, retinal and choroidal thickness, retinal nerve fiber layer (RNFL) thickness, and ganglion cell complex (GCC) thickness in patients with lichen planus (LP) compared with healthy controls with comparable age and sex distribution. This prospective case-control study included 35 participants with LP and 35 healthy control participants. Only the right eye of each participant was included in the analysis. Tear function was evaluated using the Schirmer I test and tear break-up time (TBUT). Axial length (AL) was measured using optical biometry, and intraocular pressure (IOP) was measured by pneumotonometry, whereas central retinal thickness (CRT), RNFL thickness, and GCC thickness were assessed using spectral-domain optical coherence tomography (SD-OCT). Choroidal thickness was measured at the subfoveal, nasal 1500 μm, and temporal 1500 μm regions using enhanced depth imaging OCT (EDI-OCT). Intraobserver reliability was evaluated using the intraclass correlation coefficient (ICC). Patients with LP demonstrated significantly lower Schirmer I test and TBUT values than controls (Schirmer I: 10.34 ± 2.17 mm vs. 18.37 ± 2.35 mm; TBUT: 10.74 ± 1.99 s vs. 13.06 ± 0.64 s; both p < 0.001). The pre-specified primary choroidal outcome, SFCT, was significantly lower in the LP group than in the control group (299.43 ± 30.03 μm vs. 345.40 ± 41.89 μm; p < 0.001). The secondary choroidal outcomes were also lower at the nasal 1500 μm region (272.23 ± 62.36 μm vs. 303.60 ± 42.09 μm; p = 0.041) and temporal 1500 μm region (283.43 ± 66.56 μm vs. 328.20 ± 42.51 μm; p = 0.011). No significant differences were observed in AL, IOP, CRT, RNFL thickness, or GCC thickness between the overall LP and control groups. In the exploratory subgroup analysis, GCC thickness was lower in patients with oral involvement than in those with cutaneous-only LP in the unadjusted comparison; however, this difference did not remain significant after Benjamini–Hochberg false discovery rate correction. No significant correlations were identified between disease duration and ocular parameters. LP may be associated with reduced tear function and lower choroidal thickness, while overall retinal structural parameters were comparable with those of healthy controls. The GCC finding in the oral involvement subgroup should be regarded as exploratory and interpreted cautiously. Larger longitudinal studies incorporating standardized disease activity assessment, dry eye symptom scoring, and advanced vascular imaging are needed to clarify the ocular implications of LP.