Correlating corneal nerve alterations with corneal sensitivity measured by a new non -contact esthesiometer in ocular graft -versus -host disease patients

Purpose : To assess corneal sensitivity using a novel noncontact esthesiometer in patients with chronic ocular graft versus host disease (oGVHD) and determine its correlation with ocular surface disease severity and corneal nerve alterations. Methods : A retrospective chart review of 39 eyes of 20 patients (11 female, 9 male) with oGVHD, age >18, with no history of herpetic keratitis or cicatricial ocular diseases, active ocular allergies, ocular surgery in the prior three months, or contact lens wear was done. Clinical evaluation included corneal sensitivity with Brill non-contact esthesiometer (range 1-10 mbar), tear volume with Schirmer I test (range 0-35 mm/5’), corneal fluorescein staining (NEI 0-15 grading), and corneal subbasal nerve density (µm/mm2) with in-vivo confocal microscopy (IVCM). Results : In our oGVHD cohort, ocular surface disease severity was quantified by a decreased Schirmer (8.72±8.99), and increased NEI staining (5.38±3.7). Increased Brill values (2.71±0.97) indicated a decreased corneal sensation. The corneal nerve density parameters were overall decreased (total 9,036.88±3,278.20, main trunk 5,499.35±2,199.62, branch 3,537.53±1,826.86). Brill values correlated positively with ocular surface staining measured by NEI (r=0.25, p=0.002), and inversely with total (r=0.24, p=0.05) and branch (r=0.20, p=0.08) nerve density. Corneal staining was also found to be correlated with lower total (r=0.18, p=0.09) and branched (r=0.21, p=0.03) nerve densities. Conclusions : Our data show that corneal sensation was decreased in oGVHD patients and correlated with low corneal nerve density in IVCM. The non-contact Brill esthesiometer is a promising tool for detecting reduced sensitivity in patients with ocular surface diseases.