The eye is a window
to the whole body.
A research-grounded reference of the retinal pathologies and systemic biomarkers OCTON reasons across — from sight-threatening disease to early cardiovascular, stroke, renal and neurodegenerative signals. Every claim below is sourced to the peer-reviewed literature.
One photograph. The body's circulation and its nervous system — visible at once.
The retina is the only tissue where the microvasculature and central-nervous-system neurons can be imaged directly, non-invasively, in a living person. That makes a single fundus photograph a uniquely rich systemic biomarker — a field now formally named oculomics (Wagner et al., 2020). OCTON is built on this premise: what the eye reveals rarely stops at the eye.
The visible microvasculature
The retina is the only place in the body where arteries, veins and capillaries can be photographed directly, without breaking the skin. Their calibre, tortuosity and branching mirror the heart, brain and kidney circulation.
Exposed nervous-system tissue
The retina is a developmental outgrowth of the brain. Its nerve-fibre and ganglion-cell layers thin in step with neurodegeneration — a live, in-vivo window onto conditions like Alzheimer's, Parkinson's and MS.
Non-invasive & scalable
A fundus photo takes seconds, needs no blood draw, and can now be captured on a smartphone. Deep learning turns that image into quantified, whole-body risk — screening at a population scale.
Diabetic-retinopathy grading by deep learning matches expert ophthalmologists.
Age, blood pressure, smoking & cardiac-event risk read from a fundus photo.
Chronic kidney disease detected from the retina alone.
The 'retinal age gap' predicts mortality and incident dementia.
Vascular retinopathies
Diabetic Retinopathy
Microvascular damage from chronic hyperglycemia — a direct readout of systemic glucose control.
- • Microaneurysms
- • Dot/blot hemorrhages
- • Hard exudates
- • Cotton-wool spots
- • Neovascularization (PDR)
- 00No DR
- 01Mild NPDR
- 02Moderate NPDR
- 03Severe NPDR
- 04Proliferative DR
- › DCCT: intensive glucose control cut retinopathy progression by 54% (NEJM, 1993).
- › Deep learning grades DR from fundus photos at AUC 0.99, matching ophthalmologists (Gulshan, JAMA 2016).
Hypertensive Retinopathy
Retinal vasculature damage from systemic hypertension — the vessels visibly record blood-pressure injury.
- • Arteriolar narrowing
- • A/V nicking
- • Flame hemorrhages
- • Cotton-wool
- • Papilledema (malignant)
- 00No HR
- 01Mild (K-W I-II)
- 02Moderate (III)
- 03Malignant (IV)
- › Retinal microvascular abnormalities independently predicted incident stroke — ARIC (Wong, Lancet 2001).
Retinal Vein Occlusion
Blockage of the central or branch retinal vein — often the first visible sign of vascular disease.
- • Tortuous dilated veins
- • Flame hemorrhages in distribution
- • Macular edema
- • Cotton-wool spots
- 00None
- 01Branch RVO
- 02Central RVO
Retinal Artery Occlusion
A 'stroke of the eye' — sudden painless vision loss and an ophthalmic emergency.
- • Pale retina
- • Cherry-red spot
- • Embolus visible in vessel
- • Box-carring
- 00None
- 01Branch RAO
- 02Central RAO
- › Central retinal artery occlusion carries a high risk of subsequent cerebral stroke and is managed as a TIA-equivalent.
Macular & retinal disorders
Age-related Macular Degeneration
Leading cause of central vision loss in adults 50+.
- • Drusen deposits
- • RPE pigment changes
- • Geographic atrophy
- • Choroidal neovascularization
- 00No AMD
- 01Early dry
- 02Intermediate dry
- 03Late dry / GA
- 04Late wet / CNV
- › AREDS2: an antioxidant + zinc formula slows progression to advanced AMD by ~25% (JAMA, 2013).
Macular Edema
Fluid accumulation in the macula impairing central vision.
- • Macular thickening
- • Cystic spaces
- • Hard exudates
- • Loss of foveal reflex
- 00None
- 01Mild
- 02Moderate
- 03Severe
- › Anti-VEGF therapy improves vision in diabetic macular edema (DRCR.net Protocol T, NEJM 2015).
Epiretinal Membrane
Fibrocellular tissue on the macular surface causing distortion.
- • Cellophane reflex
- • Macular pucker
- • Distorted vessels
- 00None
- 01Mild (cellophane)
- 02Moderate
- 03Severe (macular pucker)
Macular Hole
Full-thickness defect in the foveal retina.
- • Round retinal defect
- • Surrounding cuff of edema
- • Yellow deposits
- 00None
- 01Stage 1 (impending)
- 02Stage 2-3 (full)
- 03Stage 4 (with PVD)
Optic nerve & glaucoma
Glaucoma
Progressive optic neuropathy with retinal ganglion-cell loss — silent until advanced.
- • Increased cup-to-disc
- • RNFL thinning
- • Notching of rim
- • Disc hemorrhage
- 00Low risk
- 01Suspect
- 02Definite
- › OHTS: lowering intraocular pressure halved progression to glaucoma (Arch Ophthalmol, 2002).
Papilledema / Raised ICP
Bilateral disc swelling — a neurological emergency marker.
- • Swollen optic disc
- • Blurred margins
- • Hemorrhages on disc
- • Loss of cup
- 00None
- 01Suspected
- 02Present
Optic Neuropathy / Neuritis
Inflammation or atrophy of the optic nerve.
- • Optic disc pallor
- • RNFL thinning
- • Afferent pupillary defect
- • Color desaturation
- 00None
- 01Suspected
- 02Present
- › OCT of the retinal nerve-fibre layer quantifies axonal loss and tracks MS activity.
Other ocular pathologies
Cataract
Clouding of the crystalline lens — graded by fundus clarity.
- • Reduced fundus clarity
- • Yellow/brown tint
- • Diffuse opacity
- 00None
- 01Mild
- 02Moderate
- 03Dense
Retinal Detachment
Separation of neurosensory retina from RPE — emergency.
- • Retinal tears
- • Subretinal fluid
- • Pigment tobacco dust
- • Wrinkled appearance
- 00None
- 01Suspected
- 02Present
Retinitis Pigmentosa
Inherited photoreceptor degeneration.
- • Bone spicule pigmentation
- • Waxy disc pallor
- • Attenuated vessels
- 00Early
- 01Mid-stage
- 02Advanced
Choroidal Nevus / Melanoma
Pigmented choroidal lesion — benign vs malignant.
- • Pigmented elevated lesion
- • Orange pigment
- • Subretinal fluid
- • Drusen on surface
- 00Nevus
- 01Suspicious
- 02Melanoma
Systemic risk signals · oculomics
Cardiovascular Risk
The retinal circulation is the body's only directly visible microvascular bed.
- • Arteriovenous ratio
- • Vessel tortuosity
- • Fractal dimension
- 00Low
- 01Moderate
- 02High
- › Deep learning reads age, blood pressure, smoking and 5-year cardiac-event risk from a fundus photo (Poplin, Nat Biomed Eng 2018).
Stroke Risk
Retinal arteriolar sclerosis & emboli parallel cerebral small-vessel disease.
- • Hollenhorst plaques
- • Arteriolar sclerosis
- • Retinal infarcts
- 00Low
- 01Moderate
- 02High
- › Retinal microvascular signs independently predicted incident stroke — ARIC (Wong, Lancet 2001).
Alzheimer's & Dementia
Retinal β-amyloid deposits & RNFL thinning as an early neurodegeneration marker.
- • Retinal Aβ plaques
- • RNFL / GC-IPL thinning
- • Microvascular sparsity
- 00Negative
- 01Positive markers
- 02Strong markers
- › Retinal amyloid-β was imaged in Alzheimer's disease and correlated with brain plaque (Koronyo, JCI Insight 2017).
Multiple Sclerosis Signal
Optic-neuritis history plus RNFL thinning tracks demyelination.
- • RNFL thinning (esp. temporal)
- • Optic disc pallor
- • History of optic neuritis
- 00Negative
- 01Suggestive
- 02Strong
Anaemia Signal
Retinal pallor & haemorrhages in severe anaemia — and now quantifiable by AI.
- • Retinal pallor
- • Roth spots
- • Cotton-wool spots
- 00Negative
- 01Mild signs
- 02Severe
- › Deep learning estimates haemoglobin and detects anaemia from fundus images (Mitani, Nat Biomed Eng 2020).
Chronic Kidney Disease Signal
The retinal microvasculature mirrors the kidney's glomerular circulation.
- • Microvascular rarefaction
- • Overlap with diabetic nephropathy
- • Vessel-calibre change
- 00Negative
- 01Suggestive
- 02Strong
- › A deep-learning algorithm detected chronic kidney disease from retinal photographs (Sabanayagam, Lancet Digital Health 2020).
Retinal Biological Age
The retina ages measurably; the gap versus chronological age tracks whole-body health.
- • Vascular fractal dimension
- • Vessel density
- • RNFL / GC-IPL thickness
- 00Younger than age
- 01On track
- 02Accelerated ageing
- › A larger 'retinal age gap' predicted higher mortality and incident dementia (Zhu, Br J Ophthalmol 2022).
Oncology · Esophageal cancer
Esophageal Adenocarcinoma
Lower-esophagus / junction cancer on the reflux → Barrett's pathway — fastest-rising GI cancer in the West.
- • Chronic GERD history
- • Progressive dysphagia (solids → liquids)
- • Unintentional weight loss
- • Iron-deficiency anemia
- • Central obesity risk profile
- 00T1a (endoscopically curable)
- 01T1b-T2
- 02T3 / node-positive
- 03T4 / metastatic
Esophageal Squamous Cell Carcinoma
Upper/mid-esophagus cancer driven by tobacco (smoked & chewed), alcohol and scalding-hot drinks (>65°C, IARC 2A).
- • Tobacco + alcohol synergy
- • Betel/areca nut use
- • Very hot beverages (maté)
- • Odynophagia
- • Hoarseness (RLN involvement)
- 00Dysplasia
- 01Localized
- 02Locally advanced
- 03Metastatic
Barrett's Esophagus (precursor)
Reflux-driven intestinal metaplasia — the surveillance window where cancer is preventable.
- • Salmon-colored mucosa on endoscopy
- • Intestinal metaplasia on biopsy
- • ±Dysplasia grading
- • Cytosponge-TFF3 positive
- 00No dysplasia
- 01Low-grade dysplasia
- 02High-grade dysplasia
- 03Intramucosal carcinoma
Red Flags & Care Pathway
Persistent dysphagia at any age = urgent endoscopy (2-week-wait standard). OCTON's Voice Live conducts the structured triage interview.
- • Progressive dysphagia
- • Weight loss + reflux (≥55)
- • GI bleeding / melaena
- • Endoscopy + biopsy → EUS → PET-CT
- • CROSS / FLOT / immunotherapy era treatment
- 00Symptom triage
- 01Urgent endoscopy
- 02Staging
- 03MDT treatment
Oncology · Oral & throat cancer
Oral Cavity Squamous Cell Carcinoma
Tobacco, alcohol and betel/areca nut driven — the mouth is the one cancer site you can SEE early.
- • Non-healing ulcer >3 weeks
- • Red patch (erythroplakia)
- • White patch (leukoplakia)
- • Neck lump
- • Unexplained loose teeth
- 00Premalignant disorder
- 01Stage I-II (70-90% survival)
- 02Locally advanced
- 03Recurrent/metastatic
Betel / Areca Nut Disease
IARC Group-1 carcinogen even without tobacco — drives oral submucous fibrosis and cancer across South Asia & the Gulf.
- • Paan / gutka / supari use
- • Progressive trismus (mouth stiffening)
- • Burning on spicy food
- • Blanched, rigid mucosa
- 00Habit exposure
- 01Submucous fibrosis
- 02Dysplasia
- 03Carcinoma
HPV Oropharyngeal Cancer
Tonsil / tongue-base cancer rising in never-smokers — distinctly better prognosis (Ang 2010), vaccine-preventable.
- • One-sided sore throat
- • Referred ear pain
- • Neck lump
- • p16-positive histology
- 00HPV exposure
- 01Localized
- 02Nodal spread
- 03Metastatic
Mouth Self-Exam & Screening
2-minute mirror check monthly; visual screening cut oral-cancer mortality by a third in the Kerala RCT.
- • Cheeks & inner lips
- • All tongue surfaces + floor of mouth
- • Gums & palate
- • Anything persisting 3 weeks → specialist
- 00Self-exam
- 01Dental opportunistic check
- 022-week-wait referral
- 03Biopsy
Cardiovascular disease & stroke
Heart Attack (Myocardial Infarction)
The world's #1 killer — 90% of risk is modifiable (INTERHEART). Crushing chest pain >15 min = emergency call, now.
- • Crushing central chest pressure
- • Radiation to arm/jaw
- • Sweating + nausea
- • Breathlessness
- 00Risk factors
- 01Angina
- 02Acute MI
- 03Heart failure
Stroke & TIA
Think FAST: Face, Arm, Speech, Time. A TIA that 'went away' is the highest-risk emergency of all.
- • Face drooping
- • Arm weakness
- • Speech difficulty
- • Sudden vision loss
- • Worst-ever headache
- 00TIA
- 01Ischaemic stroke
- 02Thrombectomy window
- 03Rehabilitation
The Retina–Heart Window
OCTON's home turf: retinal microvascular signs predicted stroke (Wong 2001); AI reads CV risk from fundus photos (Poplin 2018).
- • Arteriolar narrowing
- • AV nicking
- • Retinal hemorrhages
- • Cotton-wool spots
- 00Normal vessels
- 01Grade 1-2 changes
- 02Grade 3
- 03Grade 4 (accelerated)
Atrial Fibrillation
An irregular pulse that multiplies stroke risk ~5× — and anticoagulation slashes it. Feel your pulse.
- • Irregularly irregular pulse
- • Palpitations
- • Breathlessness
- • Often silent
- 00Paroxysmal
- 01Persistent
- 02Permanent
- 03Anticoagulated (protected)
Oncology · Lung cancer
Non-Small-Cell Lung Cancer
~85% of lung cancer — now treated by molecular profile (EGFR/ALK/PD-L1), not just histology.
- • Cough >3 weeks or changing
- • Haemoptysis (any amount)
- • Weight loss
- • Chest/shoulder pain
- 00Stage I (surgical, 60-90%)
- 01Stage II-III
- 02Stage III (PACIFIC era)
- 03Stage IV (targeted/immuno)
Small-Cell Lung Cancer
~15%, almost exclusively in smokers — fast-growing, early spread, chemo-sensitive.
- • Rapid symptom onset
- • Heavy smoking history
- • Paraneoplastic syndromes
- • Early nodal spread
- 00Limited stage
- 01Extensive stage
Low-Dose CT Screening
Proven mortality reduction (NLST −20%, NELSON −24%) for 50-80 with heavy smoking history — massively under-used.
- • Age 50-80
- • ≥20 pack-years
- • Current or quit <15 yrs
- • Annual LDCT
- 00Eligibility check
- 01Baseline scan
- 02Nodule surveillance
- 03Early resection
Quit-Smoking Dividend
Quitting by ~40 recovers ~9 of the 10 years smoking costs (Jha 2013). It is never too late to gain years.
- • Pack-year count
- • Cigars count too
- • Beta-carotene supplements HARM smokers (ATBC)
- • Support doubles quit rates
- 00Contemplation
- 01Quit attempt
- 021 year smoke-free
- 03Risk falling every year
Oncology · Colorectal cancer
Adenoma → Carcinoma Sequence
Most bowel cancers grow from benign polyps over 10-15 years (Vogelstein) — removing the polyp prevents the cancer.
- • Often silent for years
- • Polyps on colonoscopy
- • APC → KRAS → TP53 progression
- 00Small adenoma
- 01Advanced adenoma
- 02Early carcinoma
- 03Invasive cancer
Red Flags
Rectal bleeding, a month of changed bowel habit, or unexplained anaemia — never assume 'just piles'.
- • Blood in stool
- • Persistent habit change
- • Iron-deficiency anaemia
- • Weight loss
- • Tenesmus
- 00Symptom triage
- 01FIT test
- 02Urgent colonoscopy
- 03Staging
Screening Works
FOBT cut mortality 33% (Minnesota); colonoscopy removes the risk it finds (NordICC). A FIT kit takes 2 minutes at home.
- • FIT from 45-50
- • Earlier with family history
- • Lynch/FAP programs
- • Attendance is everything
- 00Home FIT
- 01Colonoscopy if positive
- 02Polypectomy
- 03Surveillance
Immunotherapy Era (dMMR)
In mismatch-repair-deficient rectal cancer, dostarlimab achieved 100% clinical complete response (Cercek 2022) — every tumour tested for MSI/MMR.
- • MSI-high / dMMR biopsy
- • PD-1 blockade response
- • Organ preservation possible
- 00Molecular testing
- 01Immunotherapy
- 02Watch-and-wait
- 03Surgery if needed