Glaucoma

High myopia affects over one billion people globally and is a leading cause of irreversible vision loss, partly through myopic optic neuropathy – a glaucoma-like optic nerve degeneration driven by biomechanical factors rather than raised IOP. Preclinical researchers studying myopia progression face the challenge of distinguishing primary refractive changes (axial elongation, altered refraction) from secondary neurodegenerative consequences (RGC dysfunction, optic nerve damage) that carry the glaucoma-relevant clinical significance. Standard myopia models are typically evaluated for refractive endpoint (photorefractor, diopters) but lack paired functional assessments that would capture the RGC-circuit consequences of prolonged axial growth.

The distinction matters for translational strategy: a drug that slows axial elongation may still fail to protect RGCs, and conversely, a neuroprotective agent may preserve visual function even as axial elongation continues. Functional visual acuity – rather than refractive state alone – is therefore a critical co-readout in myopia research with glaucoma-translational implications. For the primary discussion of myopia model endpoints and refractive measurement strategies, see Myopia, Refractive Development, and Eye Growth.

Most preclinical glaucoma models rely on mechanical elevation of IOP (microbead occlusion, laser photocoagulation, episcleral vein cauterisation) as the primary driver of RGC loss. These models are well validated but do not address the subtype of glaucoma that develops without elevated IOP – so-called normal-tension glaucoma (NTG) – which accounts for a substantial proportion of glaucoma cases, particularly in older populations. NTG is thought to involve vascular dysregulation, impaired optic nerve head perfusion, and disrupted neuroprotective signalling rather than mechanical compression per se. The NO-sGC-cGMP axis sits at the intersection of these mechanisms: nitric oxide regulates trabecular meshwork tone and aqueous outflow, while the downstream cGMP signal provides direct neuroprotection to RGCs.

Researchers studying systemic aging and CNS decline encounter glaucoma-like phenotypes in models where the primary manipulation is metabolic or vascular (sGC knockout, NO-donor pharmacology, PPAR-gamma activation) rather than ophthalmic. These aging-context publications require a functional visual endpoint that is sensitive to progressive, sub-acute RGC loss rather than the rapid catastrophic loss seen in acute IOP-elevation models. For the broader framing of aging-associated neurodegeneration, see Systemic Aging and CNS Decline. For therapeutic strategies that cross over from aging to glaucoma recovery, see Maintaining and Restoring Vision.

Inherited forms of glaucoma – including juvenile open-angle glaucoma, normal-tension glaucoma linked to OPTN and TBK1 mutations, and glaucoma occurring as a secondary feature of rare connective tissue or metabolic disorders – are often under-represented in preclinical model catalogues that focus on acquired, pressure-dependent glaucoma. Researchers working in the rare-and-inherited disease space face the compounded challenge of modelling both the primary genetic disorder and its glaucoma-related sequelae, and of selecting which of several available mouse models best recapitulates the clinically relevant functional deficit.

A further dimension arises when molecular programmes studied in the context of inherited retinal degeneration – most notably the SARM1 axon-degeneration pathway – are found to be equally active in glaucomatous RGC loss. This convergence means that a researcher developing SARM1-targeting therapies for inherited retinal dystrophy may simultaneously generate evidence directly relevant to glaucoma neuroprotection. For the broader rare-disease research context, see Rare and Inherited CNS and Eye Disorders. For the retinal-degenerative context, see Retinal Degeneration and Inherited Retinal Disease.

Neuroinflammatory signalling pathways are broadly active across multiple disease contexts: autoimmune conditions, retinal dystrophies, systemic metabolic disorders, and direct injury. Each of these can produce secondary optic neuropathy and RGC damage that is mechanistically analogous to glaucoma even when IOP is normal and the initiating pathology is not glaucomatous. This creates both a scientific challenge – disentangling primary versus secondary RGC loss mechanisms – and a translational opportunity: anti-inflammatory interventions validated in one disease context may be directly applicable to glaucoma.

Researchers in the neuroinflammation and retinal-degeneration fields often encounter glaucoma-like functional endpoints without intending to study glaucoma. The question then becomes whether their standard endpoint battery (histology, ERG, structural OCT) captures the full extent of RGC circuit dysfunction. Automated optomotor testing adds a functional circuit-level readout that is directly comparable across contexts. For the primary neuroinflammation framing, see Neuroinflammation and Autoimmune CNS Disease; for retinal degeneration, see Retinal Degeneration and Inherited Retinal Disease.

Chronic IOP elevation models (DBA/2J, microbead, laser) are the standard for glaucoma research but require weeks to months before measurable functional deficits emerge, making them unsuitable for rapid pharmacological screening or mechanistic studies requiring defined time courses. Acute models – IRI and ONC – compress the relevant pathophysiology into hours to days, enabling higher-throughput intervention testing and mechanistic dissection. The challenge is establishing how closely the acute injury mechanisms overlap with those operative in chronic glaucoma: if the same cell-death programmes (necroptosis, oxidative stress, dopamine dysregulation) are active in both contexts, then a drug validated in an acute model has a stronger translational argument for glaucoma application.

For the IRI model, the acute IOP spike specifically recapitulates the pathophysiology of acute angle-closure glaucoma, where IOP rises transiently to ischaemic levels. This direct mechanistic parallel justifies the IRI model as a glaucoma proxy. For ONC, the connection is less direct (no IOP involvement) but relevant to the axon-degeneration and neuroprotection questions shared between trauma and glaucoma research. For the primary trauma research framing, see Trauma and Acute Injury; for therapeutic recovery endpoints, see Maintaining and Restoring Vision.