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Updated: Jun 18, 2026
Full-Circle Cauterization of Limbal Vascular Plexus for Surgically Induced Glaucoma in Rodents
Published on: February 15, 2022
Limited restoration of visual function after partial optic nerve injury; a time course study using the calcium
Marion Selt1, Carole A Bartlett, Alan R Harvey
1Experimental and Regenerative Neurosciences, The University of Western Australia, Crawley, 6009 WA, Australia.
Abstract:
Secondary degeneration is a process encompassing damage adjacent to a primary injury, usually involving increased Ca(2+) influx into neurons and glia. Lomerizine dihydrochloride is a calcium channel blocker with relatively selective CNS effects, currently in clinical trials for glaucoma. We have recently demonstrated that, following partial transection of the optic nerve (ON), 1 month of lomerizine treatment protects retinal ganglion cells (RGCs), incompletely preserves visual function and also limits elements of secondary degeneration, including macrophage infiltration. However, under some circumstances macrophages have been shown to have different supportive effects on RGC protection and regeneration, casting doubt on the benefit of longer term therapies that reduce macrophage numbers. Here, we determined whether shorter treatment times (1 day or 1 week) result in improved effects on RGC survival and visual function, and whether benefits are maintained after cessation of treatment. We demonstrate that 1 month of lomerizine is the minimum period required to restore the fast reset phase of the optokinetic nystagmus and maintain it for a further 2 months after cessation of treatment (p>0.05, not different from normal). While 1 week of lomerizine treatment results in temporary recovery of numbers of fast reset phases, the recovery is not maintained after treatment cessation. Similarly, protection of RGC densities requires 1 month of lomerizine treatment, but protection is not maintained after treatment cessation. Importantly, none of the lomerizine treatment protocols resulted in full restoration of visual function, confirming the necessity of combining lomerizine with other treatment modalities.
Insights
One month of lomerizine dihydrochloride treatment is necessary to protect retinal ganglion cells and restore visual function after optic nerve injury. Shorter treatments or cessation of lomerizine dihydrochloride lead to loss of benefits.
Area of Science:
- Neuroscience
- Ophthalmology
- Pharmacology
Background:
- Secondary degeneration, characterized by neuronal and glial damage due to increased calcium influx, occurs adjacent to primary injuries.
- Lomerizine dihydrochloride, a calcium channel blocker with central nervous system effects, is being investigated for glaucoma treatment.
- Previous studies showed lomerizine dihydrochloride protects retinal ganglion cells (RGCs) and limits macrophage infiltration after optic nerve injury.
Purpose of the Study:
- To determine if shorter treatment durations (1 day or 1 week) of lomerizine dihydrochloride improve RGC survival and visual function.
- To assess if the benefits of lomerizine dihydrochloride treatment are sustained after its cessation.
- To establish the minimum effective treatment period for lomerizine dihydrochloride in optic nerve injury models.
Main Methods:
- Partial transection of the optic nerve in a preclinical model.
- Administration of lomerizine dihydrochloride for varying durations (1 day, 1 week, 1 month).
- Assessment of RGC survival, visual function (optokinetic nystagmus), and macrophage infiltration.
Main Results:
- One month of lomerizine dihydrochloride treatment was the minimum duration required to restore and maintain the fast reset phase of optokinetic nystagmus for 2 months post-treatment.
- One week of lomerizine dihydrochloride treatment provided only temporary recovery of fast reset phases, which were not sustained after treatment cessation.
- Sustained RGC density protection required 1 month of lomerizine dihydrochloride treatment, but this protection was not maintained after treatment cessation.
- No lomerizine dihydrochloride treatment protocol fully restored visual function.
Conclusions:
- A minimum of 1 month of lomerizine dihydrochloride treatment is essential for sustained RGC protection and visual function recovery following optic nerve injury.
- Shorter treatment durations or discontinuation of lomerizine dihydrochloride limits long-term therapeutic benefits.
- Combining lomerizine dihydrochloride with other therapeutic strategies is necessary for complete visual function restoration.
