Correlations between the Clinical Characteristics of Diabetic Trochlear Nerve Palsy and Diplopia Severity

IMPORTANCE The clinical characteristics of diabetic trochlear nerve palsy are relatively rare, and its relevance tothe severity of diplopia deserves to be analyzed. OBJECTIVE To clarifythe clinical characteristics of diabetic trochlear nerve palsy patients and their correlation with the severity of diplopia. DESIGN, SETTING, AND PARTICIPANTS Medical records of 609 isolated trochlear nerve palsy patients admitted to the Ocular Motility Disorder Treatment Centre of the First Affiliated Hospital of Harbin Medical University between December 2018 and October 2024 were reviewed and 92 eligible cases were enrolled in this study. MAIN OUTCOMES AND MEASURES To evaluate the orientation and severity of diplopia, all patients were examined with neuroimaging, completed the computerized diplopia test and were assessed with the Ocular Motor Nerve Palsy Scale. RESULTS Among the 92 patients aged 44 to 86 years (62.10±8.04 years), the majority of the patients were male (n=67, 73%). Left eye onset occurred in 44 patients, with bilateral trochlear nerve palsy not reported. The duration of diabetes ranged from 0.5 to 30 years (11.37±8.02 years), and the time of onset for all patients ranged from 2 to 111 days (14.68±15.64 days). The average level of hemoglobin A1c (HbA1c) was 8.02±1.48(%) and the average maximum vertical deviation was 5.38±2.18. A significant correlation was found between the duration of diabetes and the severity of diplopia (P=0.026) but other indicators were not. The duration of diabetes was an independent risk factor for the severity of diplopia (P=0.035, OR=1.004, 95% CI, 1.001–1.008). CONCLUSIONS AND RELEVANCE This retrospective study suggests that the duration of diabetes plays an important role in diabetic trochlear nerve palsy and a longer duration of diabetes could lead to more severe diplopia in patients. The finding of this study may provide help for clinical treatment and prognosis.