AIM:To investigate the efficacy of domestic cyclosporine A(CsA)in dry eye and its effect on sub-basal nerves(SBN)by observing quantitative and morphological changes in corneal SBN of patients with moderate to severe dry eye before and after the treatment with 0.05% CsA eye drops(Ⅱ).

METHODS: In this prospective study, a total of 20 patients(20 eyes)with moderate to severe dry eye who admitted to the ophthalmology department of the Affiliated Eye Hospital of Nanchang University from December 2020 to January 2022 were selected. They were treated with domestic CsA and followed up for 3mo. Clinical evaluation was carried out at baseline and at 3mo after treatment. The changes in clinical symptoms, signs and morphology and quantity of SBN were observed.

RESULTS: The ocular surface disease index(OSDI)score, the tear break-up time(TBUT), Schirmer Ⅰ, corneal fluorescein staining(CFS)score were significantly improved at 3mo after treatment. Confocal microscopy data analysis showed that SBN density increased from 13.49±5.43 mm/mm² to 14.93±5.34 mm/mm²(P<0.001), nerve curvature scores decreased from 2.86±0.92 to 2.31±0.75(P<0.001), number of beaded structure decreased from 1.45±0.67/100μm to 1.07±0.45/100μm(P<0.001), and the number of dendritic cell(DC)decreased from 5.83±3.28 per frame to 3.67±2.24 per frame at 3mo after treatment(P<0.001). The number of DC was positively correlated with the number of branch nerves, the grade of nerve curvature and the number of nerve bead.(r_s=0.27, P=0.045; r_s=0.407, P<0.01; r_s=0.486, P<0.01).

CONCLUSIONS: Nerve injury was positively correlated with corneal inflammation caused by dry eye, and 0.05%CsA eye drops(II)could effectively inhibit inflammation and improve the morphology and quantity of corneal SBN. Observation of corneal SBN via in vivo confocal microscopy can be used as an effective method to evaluate the therapeutic effect of dry eye patients.