NEFL and Duane retraction syndrome: No significant correlation between biomarkers and age, gender, etiology, DRS, and CRS-R has been observed (Table 5b), although CRS-R showed a moderate correlation with NF-L (ρ = −0.515), UCH L1 (ρ = −0.564) and T-Tau (ρ = −0.608) at t2.