Correlations between the clinical characteristics of diabetic trochlear nerve palsy and diplopia severity

Few literatures reported the clinical characteristics of diabetic trochlear nerve palsy, including demographic characteristics, involvement between both eyes, time of symptom onset, duration of diabetes, etc. Whether there is relevance between these data and the severity of diplopia deserves to be analyzed.

To clarify the clinical characteristics of diabetic trochlear nerve palsy patients and their correlation with the severity of diplopia.

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.

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.

Among the 92 patients aged 44 to 86 years (62.10 ± 8.04 years), the majority of the patients were male (n = 67, 73%)with no bilateral trochlear nerve palsy reported in all patients. The duration of diabetes ranged from 0.5 to 30 years (11.37 ± 8.02 years), and the time of symptom 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).

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. Findings of this study may provide help for clinical treatment and prognosis.