Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 3 complete abstracts (552 words), 9 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
The transparent anterior portion of the fibrous coat of the eye consisting of five layers: stratified squamous corneal epithelium; bowman membrane; corneal stroma; descemet membrane; and mesenchymal corneal endothelium. It serves as the first refracting medium of the eye. It is structurally continuous with the sclera, avascular, receiving its nourishment by permeation through spaces between the lamellae, and is innervated by the ophthalmic division of the trigeminal nerve via the ciliary nerves and those of the surrounding conjunctiva which together form plexuses. (Cline et al., Dictionary of Visual Science, 4th ed)
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Corneas.
Where it fits in the MeSH classification
- Broader topics
- Anterior Eye Segment
- Narrower topics
- Bowman Membrane; Corneal Stroma; Descemet Membrane; Endothelium, Corneal; Epithelium, Corneal; Limbus Corneae
- See also
- Endothelium, Corneal; Keratotomy, Radial; Photorefractive Keratectomy
Related concepts
- Corneal Epithelium
- Bowman Membrane
- Corneal Stroma
- Descemet Membrane
- Corneal Endothelium
- Sclera
- Trigeminal Nerve
Research landscape
PubMed indexes 74,516 records tagged with the MeSH heading “Cornea” (counts retrieved 2026-10-31). 13,122 of them (17.6%) were published from 2020 onward, and the busiest period so far is through 1999 with 28,207 records.
Reviews account for 4,751 records (6.4%) and meta-analyses for 209. Randomized controlled trials number 1,958 (2.6%) as a share of all records on the topic.
Show the data
| Period | Records |
|---|---|
| through 1999 | 28,207 |
| 2000-2009 | 14,331 |
| 2010-2019 | 18,856 |
| 2020 onward | 13,122 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 4,751 | 6.4% |
| Meta-analyses | 209 | 0.3% |
| Randomized controlled trials | 1,958 | 2.6% |
Method: PubMed query "Cornea"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-31.
Reading the evidence in anatomy and physiology
Anatomy describes how body structures are built and physiology describes how they normally work, so most findings here are descriptive or mechanistic rather than evidence about treatment. Much of what is known comes from dissection, imaging, tissue studies and experiments in animals, and measurements in healthy volunteers can differ from those in people with disease or at different ages. Normal ranges vary between individuals and populations. Check whether a result was measured in people or in another species, the age and health of the participants, and the method used.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| SIRT1 Prevents Ferroptosis in Corneal Epithelial Cells by Enhancing HIF1α Protein Stability in Dry Eye Disease | 2026 | Research article Design not recorded in structured metadata | 4 | cc by PMID 41739054 · DOI · PMC13159161 |
| Mucoadhesive and corneal permeable nano eye drops for improved anti-glaucoma therapy | 2026 | Research article Design not recorded in structured metadata | 3 | cc by PMID 41692731 · DOI · PMC12961861 |
| The production of the chemokine CCL2 by corneal sensory neurons initiates anti-viral immunity at the cornea and trigeminal ganglion | 2026 | Research article Design not recorded in structured metadata | 3 | cc by PMID 41405994 · DOI · PMC13042276 |
SIRT1 Prevents Ferroptosis in Corneal Epithelial Cells by Enhancing HIF1α Protein Stability in Dry Eye Disease [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Hyperosmotic stress induced by tear film instability significantly exacerbates oxidative damage in corneal epithelial cells, contributing to the pathogenesis of dry eye disease (DED).
- Closing excerpt
- These results reveal a previously unrecognized pathway of ferroptosis regulation in DED and suggest a potential therapeutic strategy for reducing oxidative damage in corneal epithelium.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (159 words)
Hyperosmotic stress induced by tear film instability significantly exacerbates oxidative damage in corneal epithelial cells, contributing to the pathogenesis of dry eye disease (DED). Ferroptosis, an iron-dependent form of cell death driven by lipid peroxidation, has been identified as a critical downstream mechanism of oxidative damage in DED. However, its precise regulatory mechanisms remain unclear. In this study, we demonstrate that hyperosmotic stress promotes ferroptosis in corneal epithelial cells by downregulating the NAD-dependent deacetylase sirtuin 1 (SIRT1). SIRT1 positively regulates GPX4, a pivotal mediator of ferroptosis. Pharmacological activation of SIRT1 using SRT1720 alleviated oxidative damage and suppressed ferroptosis in corneal epithelial cells both in vitro and in vivo. Mechanistically, we further observed that SIRT1 deacetylates the HIF1α, stabilizing it via the ubiquitin-proteasome pathway. The SIRT1-HIF1α axis positively regulates GPX4 levels, thereby inhibiting ferroptosis activation. These results reveal a previously unrecognized pathway of ferroptosis regulation in DED and suggest a potential therapeutic strategy for reducing oxidative damage in corneal epithelium.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41739054 · DOI · PMC13159161
Mucoadhesive and corneal permeable nano eye drops for improved anti-glaucoma therapy [2]
Abstract reading summary — source excerpts
- Opening excerpt
- Glaucoma, characterized by elevated intraocular pressure (IOP), is the leading cause of irreversible vision loss worldwide.
- Closing excerpt
- Collectively, these findings highlight the potential of natural biopolymer-based nanosystems as efficient eye drop formulations for glaucoma treatment.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (243 words)
Glaucoma, characterized by elevated intraocular pressure (IOP), is the leading cause of irreversible vision loss worldwide. While topical eye drops remain the standard for IOP control, ocular surface dynamic and static barriers significantly limit intraocular drug bioavailability. Enhancing corneal retention and permeability is therefore crucial for effective glaucoma therapy. Here, we developed lignin-based nanoparticles coated with quaternary ammonium chitosan oligosaccharide (Lig-QCOS) for encapsulating and delivering the lipophilic drug latanoprost (Lat), a first-line hypotensive agent. The resulting Lat@Lig-QCOS nanoparticles exhibited a hydrodynamic size of ~ 225.6 nm, a low polydispersity index of 0.08, and a positive Zeta potential of + 21.5 mV. The positively charged surface enables prolonged ocular mucoadhesion and concurrently modulates corneal epithelial tight junctions, enhancing paracellular permeation. This dual mechanism increased corneal permeability by 2.2-fold within 6 h, thereby promoting transcorneal drug transport. In a dexamethasone-induced mouse glaucoma model, a single topical dose of Lat@Lig-QCOS nanoparticles achieved a superior IOP reduction compared to free Lat and anionic Lat@Lig nanoparticles. The formulation produced a maximum IOP reduction of 5.2 mmHg, outperforming the commercial Xalatan® (4.1 mmHg), and sustained efficacy for up to 10 h. The area under the pharmacodynamic response curve (AUC) of Lat@Lig-QCOS was 3.1-fold greater than that of free latanoprost, indicating markedly improved therapeutic performance. Comprehensive in vitro and in vivo biocompatibility assessments confirmed the excellent safety profile of the Lig-QCOS nanocarrier. Collectively, these findings highlight the potential of natural biopolymer-based nanosystems as efficient eye drop formulations for glaucoma treatment.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41692731 · DOI · PMC12961861
The production of the chemokine CCL2 by corneal sensory neurons initiates anti-viral immunity at the cornea and trigeminal ganglion [3]
Abstract reading summary — source excerpts
- Opening excerpt
- The cornea is an epithelial tissue densely innervated by sensory neurons but devoid of autonomic innervation, lymphatics, and vasculature.
- Closing excerpt
- These experiments demonstrate that corneal afferent activation is sufficient to trigger inflammatory responses that can assist the host in initiating anti-viral immunity.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (150 words)
The cornea is an epithelial tissue densely innervated by sensory neurons but devoid of autonomic innervation, lymphatics, and vasculature. The simplicity of the cellular composition suggests that corneal afferents participate in tissue homeostasis by regulating immune cells. Transcriptomic analysis of retrogradely labeled corneal afferents in the trigeminal ganglion (TG) found that they express many immune-related genes. Optogenetic activation of corneal afferents increased neutrophils and monocytes in both the cornea and TG, as well as inducing phenotypic changes in natural killer (NK) cells. Unsupervised pathway analysis indicated neuronally expressed Ccl2 as a modulator of immune cell responses. Selective deletion of neuronal Ccl2 decreased the number of myeloid cells in the cornea and TG in response to herpes simplex virus (HSV) infection, resulting in compromised viral clearance during primary infection. These experiments demonstrate that corneal afferent activation is sufficient to trigger inflammatory responses that can assist the host in initiating anti-viral immunity.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41405994 · DOI · PMC13042276
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Ocular Drug Delivery: a Comprehensive Review [4]
- Research article Clinical Outcomes of SMILE and FS-LASIK Used to Treat Myopia: A Meta-analysis [5]
- Research article IntraLase femtosecond laser vs mechanical microkeratomes in LASIK for myopia: a systematic review and meta-analysis [6]
- Research article Corneal Collagen Cross-Linking for Infectious Keratitis: A Systematic Review and Meta-Analysis [7]
- Research article Corneal biomechanical properties after SMILE versus FLEX, LASIK, LASEK, or PRK: a systematic review and meta-analysis [8]
- Research article Central corneal thickness is highly heritable: the twin eye studies [9]
References
- Lian L, Le Z, Ye X, Wang Z, Li J, Dong C, et al.. SIRT1 Prevents Ferroptosis in Corneal Epithelial Cells by Enhancing HIF1α Protein Stability in Dry Eye Disease. . 2026. PMID 41739054 · DOI · PMC13159161
- Zhang X, Shao Q, Yu M, Huang Y, Wang Y, Wen Y, et al.. Mucoadhesive and corneal permeable nano eye drops for improved anti-glaucoma therapy. . 2026. PMID 41692731 · DOI · PMC12961861
- Yun H, Moghbeli K, Gerges PH, Cisney RN, Yoshida M, Hawse WF, et al.. The production of the chemokine CCL2 by corneal sensory neurons initiates anti-viral immunity at the cornea and trigeminal ganglion. . 2026. PMID 41405994 · DOI · PMC13042276
- Ahmed S, Amin MM, Sayed S. Ocular Drug Delivery: a Comprehensive Review. AAPS PharmSciTech. 2023. PMID 36788150 · DOI
- Zhang Y, Shen Q, Jia Y, Zhou D, Zhou J. Clinical Outcomes of SMILE and FS-LASIK Used to Treat Myopia: A Meta-analysis. J Refract Surg. 2016. PMID 27070233 · DOI
- Chen S, Feng Y, Stojanovic A, Jankov MR, Wang Q. IntraLase femtosecond laser vs mechanical microkeratomes in LASIK for myopia: a systematic review and meta-analysis. J Refract Surg. 2012. PMID 22233436 · DOI
- Papaioannou L, Miligkos M, Papathanassiou M. Corneal Collagen Cross-Linking for Infectious Keratitis: A Systematic Review and Meta-Analysis. Cornea. 2016. PMID 26509768 · DOI
- Guo H, Hosseini-Moghaddam SM, Hodge W. Corneal biomechanical properties after SMILE versus FLEX, LASIK, LASEK, or PRK: a systematic review and meta-analysis. BMC Ophthalmol. 2019. PMID 31370817 · DOI · PMC6676534
- Toh T, Liew SH, MacKinnon JR, Hewitt AW, Poulsen JL, Spector TD, et al.. Central corneal thickness is highly heritable: the twin eye studies. Invest Ophthalmol Vis Sci. 2005. PMID 16186354 · DOI
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-31.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.