Levodopa-Carbidopa May Improve Vision Loss in Indirect Traumatic Optic Neuropathy

Abstract

To compare the effect of levodopa-carbidopa on the visual outcome of patients with indirect traumatic optic neuropathy (ITON), this randomized, double-blind, placebo-controlled study was conducted on 32 patients with ITON within 6 days after trauma. Patients underwent a complete ocular examination, pattern visual evoked potential (PVEP) testing, and high-resolution orbital computed tomography (CT) scanning. All patients received high-dose intravenous methylprednisolone, and levodopa was also administered to the levodopa group. The main outcome measures were best corrected visual acuity and PVEP results at the last-completed examination. The study was completed on 16 patients in the levodopa group and 10 patients in the placebo group because the others were lost to follow-up. There were no statistically significant differences for age, sex, involved eye, ocular and CT scan findings, pretreatment visual acuity, frequency of recordable PVEPs, and follow-up. In the levodopa group the visual acuity improved significantly after treatment (p = 0.009), but not in the placebo group (p = 0.34). After treatment the visual acuity in the levodopa group was 2.1 ± 2.1, and in the placebo group was 3.9 ± 1.2 (p = 0.008). In those who had visual acuity less than or equal to figure count, significant improvement in visual acuity was observed in the levodopa group (p = 0.03), but not in the placebo group (p = 0.34). However, the final visual acuity in these patients was comparable after treatment (p = 0.21). Nine patients (56.2%) in the levodopa group, and 1 (10%) in the placebo group, experienced improvement in visual acuity (p = 0.02). The frequency of unrecordable PVEPs were comparable in both groups (p = 0.09). Patients treated with levodopa within 6 days of onset of ITON were more likely to experience improvement in visual acuity than those in the placebo group.

Neuroprotective strategies for retinal disease

“…L-DOPA treatment was also shown to increase dopamine levels in the retinas of Parkinson’s patients (Harnois and Di Paolo, 1990), and to reduce deficits in contrast sensitivity (Hutton et al, 1993), visual evoked potentials (Onofrj et al, 1986), and pattern ERG (Peppe et al, 1995). Furthermore, L-DOPA administration may protect against visual function loss in patients with ischemic and traumatic optic neuropathies (Lyttle et al, 2016; Razeghinejad et al, 2010, 2016). In addition to its potential neuroprotective role, the dopaminergic system may be involved in regulating intraocular pressure, with D1 receptor agonists increasing aqueous production (and thus IOP), and D2 and D3 agonists decreasing intraocular pressure (Pescosolido et al, 2013).…”

Indirect traumatic optic neuropathy

“…A 2010 study investigated the potential additive effect of providing levodopa-carbidopa to improve the visual outcomes of patients with indirect traumatic optic neuropathy (ITON) [ 28 ]. The rationale behind this study was that steroids should be offered because they were considered a mainstay of treatment and that the neuro-protective effect of levodopa may enhance outcomes [ 29 ].…”

Factor de crecimiento nervioso en neuropatía óptica traumática

“…Además de la descompresión del canal óptico como terapia quirúrgica principal, algunos estudios reportaron los beneficios de la eritropoyetina intravenosa, o también el uso de corticoides (7) . La levodopa-carbidopa se aplicó a pacientes con iTON (8) . Sin embargo, no está claro el tratamiento adecuado para un iTON (7) .…”