cornea
Enable an AI agent to recognise a cornea, record its optical and biological condition, and identify the evidence and authorisation needed for examination, protection, or intervention.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
recalled by Codex without web access - no source was read
Researched by: Codex
Purpose and description
Enable an AI agent to recognise a cornea, record its optical and biological condition, and identify the evidence and authorisation needed for examination, protection, or intervention.
The cornea is the transparent, normally avascular anterior part of the eye's outer coat that protects intraocular structures and supplies much of the eye's refractive power.
It can be Associate examinations and images with a specific eye, corneal region, and tissue layer.; Compare thickness, geometry, clarity, and surface integrity across suitably matched observations.; Map defects, scars, vessels, and graft interfaces to their anatomical locations.; Identify missing or unreliable evidence before drawing conclusions about corneal condition.; Record tissue-specific prerequisites and professional authorisation for examination, sampling, surgery, or graft handling.; Track the identity and condition of donor corneal tissue through storage, preparation, and implantation..
Distinguishing features
Occupies the anterior eye wall in front of the iris and pupil; the crystalline lens is an internal optical structure behind the iris.
Meets the sclera at the limbal transition; it is distinguishable from the adjacent opaque sclera by its position and specialised transparent tissue organisation.
Contains organised epithelial, stromal, and endothelial tissue rather than being the tear film coating its anterior surface.
Forms a continuous biological tissue barrier; a contact lens rests on the ocular surface and is a separate removable object.
Remains identifiable as cornea when scarred, swollen, or vascularised, so transparency alone cannot establish or exclude its identity.
Scope
+ Corneal identity, species, eye laterality, anatomical extent, and native or graft status
+ Corneal tissue layers, regional thickness, curvature, and mechanical condition
+ Transparency, refractive contribution, surface regularity, and optical quality
+ Epithelial integrity, stromal hydration, endothelial condition, and sensory innervation
+ Corneal observations, changes over time, and tissue-specific constraints on handling or intervention
- The whole eye, orbit, and systemic health as independently modelled entities
- The sclera, conjunctiva, iris, crystalline lens, and retina beyond their relationships to the cornea
- The tear film and lacrimal apparatus beyond their effects on the corneal surface
- Corneal diseases as independent diagnostic entities
- Contact lenses, surgical instruments, medicines, and artificial corneal implants as products
- Clinical procedures, transplant allocation, and treatment protocols as independently governed activities
Characteristics
- Biological and anatomical identity
- Species; host or donor identifier; right or left eye; attached tissue or explant Prevents observations from being assigned to the wrong eye, organism, or tissue specimen.
- Tissue composition and graft status
- Native; full-thickness graft; anterior lamellar graft; endothelial graft; mixed host and donor tissue; unknown Determines which layers belong to the observed tissue and where surgical interfaces may exist.
- Regional corneal thickness
- µm, with location, minimum-thickness position, method, and timestamp Supports assessment of regional thinning, swelling, and structural change.
- Anterior and posterior surface geometry
- Radius in mm, elevation in µm, and axis in degrees, with surface and reference convention Describes the physical shape underlying refractive behaviour and local deformation.
- Estimated corneal optical power
- Dioptres, with measurement method and refractive-index assumptions Separates measured geometry from model-dependent estimates of refractive contribution.
- Transparency and opacity distribution
- Clear, hazy, or opaque; affected region, depth, extent, and assessment method Locates tissue changes that can obstruct or scatter transmitted light.
- Epithelial integrity
- Intact; punctate disruption; focal defect; unresolved; defect dimensions in mm where measured Records whether the anterior tissue barrier is continuous.
- Endothelial cell density
- Cells/mm², with sampled region, imaging method, and image quality Provides a regional observation relevant to endothelial maintenance of corneal hydration.
- Hydration-related tissue condition
- No oedema observed; epithelial oedema; stromal oedema; mixed; indeterminate Connects swelling observations to changes in thickness and clarity without assuming their cause.
- Corneal sensation
- Method-specific sensory threshold or documented qualitative response, with test location Records sensory function relevant to protective responses and surface maintenance.
- Vascularisation
- Absent, present, or uncertain; vessel depth, distribution, and extent Distinguishes observed vessel ingrowth from normal corneal tissue organisation.
Also called
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 15 findings · 25 questions.
Corneal identity and anatomy Identifies the tissue and establishes its anatomical boundaries and internal organisation.
Corneal observations require an unambiguous eye, region, and layer, especially when host and donor tissue coexist.
Eye and tissue boundaries
Locates the cornea within an eye or identifies it as an isolated specimen.
Corneal extent and identity
Record the species, laterality, tissue context, and evidence used to distinguish cornea from adjacent ocular structures.
- Which species, eye, and attached or explanted tissue does this record describe? provenance
- How is the cornea-to-limbus boundary identified, and does the recorded specimen include limbal or scleral tissue? boundary
Layers and regional location
Assigns observations to tissue depth and position across the cornea.
Layer and location convention
Declare the anatomical layer terminology and coordinate convention used for local findings.
- Which epithelial, stromal, endothelial, or intervening anatomical structure is being described under the declared layer convention? definition
- Where is the observation relative to the corneal centre, limbus, and eye orientation, and how was its depth established? measurement
Corneal optics and geometry Describes the shape and transparency through which the cornea contributes to ocular optics.
Corneal optical performance depends on both surface geometry and light transmission through the tissue.
Surface shape and refraction
Separates physical surface measurements from derived refractive estimates.
Surface-specific optical measurements
Record anterior and posterior geometry, astigmatic orientation, and the assumptions behind calculated corneal power.
- What anterior and posterior curvature or elevation measurements are available, over which corneal zone? measurement
- Which surfaces and refractive-index assumptions were used to calculate corneal power or astigmatism? provenance
Clarity and optical disruption
Locates opacity and irregularity while distinguishing tissue effects from neighbouring optical contributors.
Location of optical disruption
Describe the extent and depth of corneal haze, scarring, or irregularity without attributing all visual impairment to the cornea.
- Where are opacity or irregularity observed, at what depth, and do they intersect the assessed optical zone? measurement
- What evidence separates corneal tissue effects from tear-film instability, lens opacity, or other causes of reduced optical quality? boundary
Corneal barrier and structural integrity Records epithelial continuity and the thickness and stability of the underlying tissue.
Surface barrier loss and structural weakening are distinct conditions requiring different evidence and action constraints.
Epithelial surface barrier
Characterises surface disruption and its observed evolution.
Epithelial defect map
Locate epithelial defects and distinguish observed surface staining from an established explanation for the defect.
- Is the epithelium continuous, and what are the location, dimensions, and pattern of any observed disruption? measurement
- Which examination method demonstrated the disruption, and what change is documented on subsequent examination? provenance
Stromal thickness and stability
Records regional tissue thickness, deformation, wounds, and evidence of compromised continuity.
Regional structural condition
Represent thinning, swelling, shape change, and wound status using spatially matched observations.
- What are the central and minimum corneal thicknesses, where is the minimum, and are serial measurements comparable? measurement
- What documented evidence of a wound, progressive deformation, or loss of tissue continuity constrains examination or intervention? action
Corneal physiological maintenance Connects endothelial condition, hydration, sensory function, and surface support to observed tissue condition.
A cornea can retain its anatomical identity while losing the physiological support needed for clarity and surface integrity.
Endothelium and hydration
Records endothelial observations alongside the distribution and evolution of oedema.
Endothelial and oedema evidence
Keep endothelial cell measurements and hydration-related observations linked without treating either as a complete causal explanation.
- What endothelial density and cell morphology were observed, in which region, and with what image quality? measurement
- Which corneal layers show oedema, and how do its distribution and timing relate to thickness and clarity measurements? measurement
Innervation and surface support
Records sensation and the cornea's dependence on adjacent surface-maintenance systems.
Sensory and surface-support condition
Describe corneal sensory responses and relevant tear-film, eyelid, and limbal relationships.
- What corneal sensory response or threshold was measured, at which locations and using which method? measurement
- Which observed tear-film, eyelid-closure, or limbal abnormalities affect this cornea while remaining owned by neighbouring models? boundary
Corneal grafts and intervention context Tracks tissue origin, surgical alterations, and prerequisites for proposed actions.
Native, operated, and donor corneas differ in tissue ownership, interfaces, evidence requirements, and handling context.
Host, donor, and surgical interfaces
Identifies which tissue is present and how prior procedures changed its organisation.
Tissue origin and alteration history
Record native and transplanted layers, donor traceability where applicable, and documented surgical interfaces or implants.
- Which layers are native or donor-derived, and which records establish donor tissue identity and implantation history? provenance
- Which incisions, graft interfaces, sutures, or implants are present, and which belong to separate device or procedure records? boundary
Action prerequisites and tissue handling
Links proposed examination, intervention, or specimen handling to documented tissue condition and accountable decisions.
Cornea-specific action readiness
Record the intended action and the corneal evidence, professional assessment, and applicable handling instructions required before it proceeds.
- What proposed action requires assessment of epithelial integrity, regional thickness, endothelial condition, or graft interfaces, and who is authorised to decide? action
- For donor or explanted tissue, which documented preservation conditions, preparation history, and release criteria govern its intended use? provenance
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Check these first
Recalled without web access and unsourced; every item is a lead to verify.
- This describes the anatomical cornea, with measurements referring to adult humans; other species differ.
- Measurement values are approximate and vary with population, instrument and measurement convention.
- No external sources were consulted; no identifier or regulatory claim is asserted.
- Which of these check these first hold for the sense of cornea this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Refracts incoming light to help focus images on the retina.
- Forms a protective barrier at the front of the eye.
- Provides sensory input that triggers protective blinking and tearing.
- Donated corneal tissue is used in transplantation.
- Corneal shape can be modified surgically to correct refractive errors.
- Which of these real-world use hold for the sense of cornea this model covers, and on what evidence? provenance
Typical measurements
Recalled without web access and unsourced; every item is a lead to verify.
- Adult human horizontal diameter - 11-12 - mm
- Adult human central thickness - 500-600 - µm
- Adult human total corneal refractive power - Approximately 43 - dioptres
- Which of these typical measurements hold for the sense of cornea this model covers, and on what evidence? provenance
Failure modes and hazards
Recalled without web access and unsourced; every item is a lead to verify.
- Epithelial abrasion causes pain and can increase susceptibility to infection.
- Infectious keratitis can cause ulceration, scarring and perforation.
- Endothelial dysfunction can cause corneal swelling and loss of transparency.
- Corneal ectasia, including keratoconus, causes thinning, distortion and irregular astigmatism.
- Chemical injury can damage the cornea and its limbal epithelial stem-cell supply.
- Which of these failure modes and hazards hold for the sense of cornea this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Recalled without web access and unsourced; every item is a lead to verify.
- sclera - The sclera is the opaque portion of the eye's outer coat; the cornea is its transparent anterior portion.
- conjunctiva - The conjunctiva lines the eyelids and covers the anterior sclera, but does not cover the corneal surface.
- lens - The lens is an internal transparent structure behind the iris that changes shape during accommodation; the cornea forms the front surface of the eye.
- corneal limbus - The limbus is the transition zone between the cornea and sclera, rather than the cornea as a whole.
- tear film - The tear film is the renewable fluid coating over the corneal epithelium, rather than part of the corneal tissue.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of cornea this model covers, and on what evidence? provenance
What the second pass must settle
- Should the registry entry cover corneas across species, and which anatomical and physiological differences require explicit species profiles?
- Which corneal layer convention should be adopted, including the representation of proposed subdivisions of the posterior stroma?
- Which measurement methods and reference populations support meaningful interpretation of thickness, geometry, endothelial density, and sensation?
- How should the limbal transition and limbal stem-cell niche be divided between this model and neighbouring ocular models?
- Which authoritative clinical and eye-bank sources should establish action prerequisites and donor-tissue handling requirements for each intended jurisdiction and use?