Sustained Benefit of Short-Term Levodopa Treatment on Inner Retinal Function in Patients With Diabetes.

Area of Science:

• Ophthalmology
• Neuroscience
• Endocrinology

Background:

• Diabetic retinopathy (DR) is a complication of diabetes mellitus (DM).
• Preclinical DR involves early functional and structural retinal changes.
• Oscillatory potential (OP) implicit times (ITs) can detect early retinal dysfunction.

Purpose of the Study:

• To investigate the long-term effects of levodopa (L-DOPA) on retinal function and structure in preclinical diabetic retinopathy (DR).
• To assess the progression of OP implicit times (ITs) in individuals with DM with and without L-DOPA treatment over 5 years.

Main Methods:

• Re-evaluation of participants from a previous study after 5 years.
• Groups included: DM + L-DOPA (n=14), DM (n=6), and healthy controls (n=37).
• Retinal function assessed by electroretinography (ERG) and structure by optical coherence tomography (OCT).

Main Results:

• No significant differences in OP ITs among groups after 5 years (P > 0.05).
• DM + L-DOPA group showed sustained OP IT improvements from baseline.
• DM + L-DOPA group had thinner outer retinal layers (OPL, GCL) compared to the DM group (P < 0.05).
• DM group showed strong OP IT-OCT correlations; DM + L-DOPA group correlations resembled controls.

Conclusions:

• Short-term L-DOPA treatment demonstrated sustained functional benefits over 5 years.
• Inner retinal structural changes suggest long-term neuroprotective effects of L-DOPA.
• OP IT delays are potential early biomarkers for preclinical DR; L-DOPA may offer lasting benefits.