[The influence of soft contact lenses on the corneal nerve growth factor and optical quality]

Objective: To explore the correlation between the nerve growth factor (NGF) in the corneal stroma and the corneal optical quality in high myopia patients wearing soft contact lenses (SCLs) for a long time before small incision lenticule extraction (SMILE). Methods: A retrospective cohort study was conducted. Sixty high myopia patients (120 eyes) who underwent SMILE in Shanghai Tenth People's Hospital from December 2020 to October 2022 were included, with an age of (30.75±4.37) years, including 26 males and 34 females. According to the duration of wearing SCLs before surgery, they were divided into three groups: group A (wearing time>10 years), group B (wearing time≤10 years), and group C (without wearing lenses). General examinations were carried out to collect medical histories and parameters, such as uncorrected visual acuity, intraocular pressure, and axial length of the eye. The Pentacam corneal topography system was used to measure corneal higher-order aberrations, including total higher-order aberrations and various coma aberrations, and to obtain the optical density of different parts and layers of the cornea. A part of the corneal stromal lenticule was used for immunofluorescence detection, and another part was used to detect the NGF level. Results: The expression level of NGF in the corneal stromal lenticules showed an upward trend with the prolongation of the wearing time of SCLs (P<0.05). The total higher-order aberration in group A was (0.39±0.10) μm, and the horizontal coma aberration was (0.17±0.12) μm, both higher than those in group C [(0.33±0.07) μm and (0.09±0.08) μm]. The full-thickness optical density of the central 6-mm annular region of the cornea in group A (13.64±2.08) and that of the central 2-mm circular region of the cornea in group B (13.58±1.28) were both higher than that in group C (12.74±0.85) (all P<0.05). The NGF level in the corneal stromal lenticules in group A was positively correlated with the optical density of the anterior layer and the full-thickness layer within the central 6-mm circular region of the cornea (both P<0.05). In group B, the NGF level in the corneal stromal lenticules was positively correlated with the optical density of the middle layer and the posterior layer within the central 6-mm circular region of the cornea, and also positively correlated with the optical density of the middle layer and the posterior layer of the 2-mm circular region (all P<0.05). The NGF level in the corneal stromal lenticules in group C was also positively correlated with the optical density of the middle layer and the posterior layer of the 0-to 6-mm annular region of the cornea (all P<0.05). Conclusion: In high myopia patients who have worn SCLs for a long time, the expression of NGF in the corneal stromal lenticules increases, the corneal optical quality decreases, and the NGF level is closely related to the corneal optical density.