{"id":18068,"date":"2026-08-04T10:47:47","date_gmt":"2026-08-04T10:47:47","guid":{"rendered":"https:\/\/www.eyecliniclondon.com\/blog\/?p=18068"},"modified":"2026-08-04T11:21:58","modified_gmt":"2026-08-04T11:21:58","slug":"oct-systemic-disease","status":"publish","type":"post","link":"https:\/\/www.eyecliniclondon.com\/blog\/oct-systemic-disease\/","title":{"rendered":"Can OCT Scans Detect More Than Eye Disease?"},"content":{"rendered":"

Optical coherence tomography creates detailed cross-sectional images of the retina, optic nerve head and other eye structures. It can measure retinal-layer thickness and identify changes that may not be visible during a standard eye examination.<\/p>\n

OCT has established roles in diagnosing and monitoring several eye conditions and can support selected neuro-ophthalmic assessments. Researchers are also investigating associations with wider neurological and systemic diseases, but an OCT scan cannot independently diagnose most of these conditions.<\/p>\n

Why Can Your Retina Reflect General Health?<\/h2>\n

Your retina contains specialised nerve cells, nerve fibres and small blood vessels that are closely connected with your nervous and circulatory systems. Changes in these structures may reflect processes such as neurodegeneration, inflammation or microvascular damage occurring elsewhere in your body.<\/p>\n

Researchers are studying whether retinal findings could provide additional information about wider health conditions. However, retinal changes are not specific to one disease and cannot currently be used alone to diagnose general health problems.<\/p>\n

Can OCT Diagnose a Systemic Disease?<\/h2>\n

OCT cannot usually confirm a systemic condition by itself. Retinal thinning, swelling or vascular changes may be associated with several different eye, neurological and general health conditions.<\/p>\n

In selected neurological settings, OCT may contribute supporting evidence when interpreted with the clinical history, examination, MRI, blood tests or other investigations. The scan result should not be treated as a diagnosis outside its established clinical uses.<\/p>\n

What Is OCT Angiography?<\/h2>\n

OCT angiography (OCTA) is an advanced form of OCT that maps blood flow through the tiny blood vessels in your retina and choroid without the need for injected dye. It allows researchers and eye specialists to study subtle changes in your eye\u2019s microcirculation.<\/p>\n

Researchers are investigating whether OCTA findings may provide insights into conditions linked with blood vessel changes, including neurological, cardiovascular, kidney and inflammatory diseases. However, OCTA is not currently used to diagnose these conditions on its own.<\/p>\n

Multiple Sclerosis<\/h2>\n

OCT can measure the peripapillary retinal nerve fibre layer and the macular ganglion-cell and inner plexiform layers, which may become thinner after inflammatory injury to the optic nerve. These measurements can help document previous optic-nerve damage and may contribute to assessment or monitoring in selected people.<\/p>\n

The 2024 revisions to the McDonald diagnostic criteria include the optic nerve as a fifth anatomical location. OCT or visual evoked potentials may provide objective evidence of optic-nerve involvement when the required criteria are met and other causes have been excluded. OCT cannot diagnose multiple sclerosis by itself and must be interpreted alongside symptoms, neurological examination, MRI and other appropriate investigations.<\/p>\n

OCT Findings in Multiple Sclerosis<\/h2>\n\n\n\n\n\n\n\n\n\n
OCT Finding<\/strong><\/td>\nPossible Clinical Role<\/strong><\/td>\nImportant Limitation<\/strong><\/td>\n<\/tr>\n
Retinal nerve fibre layer thinning<\/td>\nMay indicate previous optic-nerve axonal injury<\/td>\nGlaucoma and other optic-nerve diseases can produce similar thinning<\/td>\n<\/tr>\n
Ganglion-cell layer thinning<\/td>\nMay support evidence of retinal nerve-cell loss<\/td>\nRequires reliable segmentation and comparison between eyes<\/td>\n<\/tr>\n
Difference between the two eyes<\/td>\nMay support previous one-sided optic-nerve involvement<\/td>\nNatural asymmetry and eye disease must be excluded<\/td>\n<\/tr>\n
Change after optic neuritis<\/td>\nHelps document structural injury over time<\/td>\nTiming affects interpretation<\/td>\n<\/tr>\n
Longitudinal measurements<\/td>\nMay contribute to monitoring neurodegeneration<\/td>\nScanner and protocol differences can affect comparisons<\/td>\n<\/tr>\n
Overall role<\/td>\nProvides an additional objective measurement<\/td>\nDoes not replace clinical examination, MRI or neurological assessment<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Optic Neuritis<\/h2>\n

\"\"<\/p>\n

Optic neuritis is inflammation of the optic nerve and can occur with multiple sclerosis, neuromyelitis optica spectrum disorder, MOG-antibody-associated disease and other conditions. OCT can help document retinal nerve and ganglion-cell changes after an episode.<\/p>\n

The retinal nerve fibre layer may appear thicker when optic-disc swelling is present, but many cases of acute optic neuritis do not cause visible disc swelling. Thinning caused by nerve-fibre loss generally becomes clearer during the following months.<\/p>\n

Raised Intracranial Pressure<\/h2>\n

Raised intracranial pressure can cause optic-disc swelling known as papilloedema. OCT can measure and document swelling around the optic nerve head and help monitor changes alongside visual fields, optic-disc photographs and examination findings.<\/p>\n

OCT cannot measure intracranial pressure or determine why papilloedema has developed. Confirmed or suspected papilloedema requires urgent assessment, including appropriate neurological investigation and brain imaging.<\/p>\n

When Papilloedema Needs Urgent Assessment<\/h2>\n

Papilloedema may indicate a serious underlying condition and requires immediate medical investigation. Seek urgent assessment for a new or severe headache accompanied by brief episodes of darkened vision, double vision, vomiting, pulsating noise in the ears or worsening eyesight.<\/p>\n

An OCT result should never delay referral when papilloedema is suspected. Diagnosis requires a full examination to distinguish true swelling from conditions that can make the optic disc appear elevated.<\/p>\n

Alzheimer\u2019s Disease<\/h2>\n

Research has reported differences in retinal nerve fibre, ganglion-cell and other retinal measurements among groups with Alzheimer\u2019s disease or cognitive impairment. However, the affected layers and size of the differences vary considerably between studies.<\/p>\n

A 2026 systematic review found that OCT biomarkers remain limited by small studies, inconsistent methods, eye and vascular confounders and insufficient external validation. OCT cannot currently diagnose, predict or rule out Alzheimer\u2019s disease.<\/p>\n

Parkinson\u2019s Disease<\/h2>\n

Some studies have reported retinal-layer and microvascular differences among groups with Parkinson\u2019s disease. However, findings vary according to the patient population, scanning method, disease duration and coexisting eye conditions.<\/p>\n

No OCT measurement is sufficiently specific to diagnose Parkinson\u2019s disease. Diagnosis remains based on neurological history and examination, with other investigations used when clinically appropriate.<\/p>\n

Other Neurodegenerative Conditions<\/h2>\n

Researchers are also investigating OCT findings in conditions such as amyotrophic lateral sclerosis and other neurological disorders. Researchers are exploring whether changes in your retina may provide information about neurodegeneration.<\/p>\n

However, the evidence is less established compared with multiple sclerosis. OCT is not currently used as a routine diagnostic test for these conditions.<\/p>\n

Stroke and Cerebrovascular Health<\/h2>\n

Changes in your retinal nerves and blood vessels may be associated with stroke risk or previous cerebrovascular damage. Researchers are studying whether OCT and OCTA can provide information about these changes.<\/p>\n

However, these scans remain research tools and cannot replace your brain imaging or a full cardiovascular assessment. Your overall health assessment is still needed to understand your risk.<\/p>\n

Diabetes<\/h2>\n

OCT has an established clinical role in assessing diabetic macular oedema by showing and measuring fluid or thickening in the central retina. It is also widely used to monitor treatment response in hospital eye services.<\/p>\n

Research is investigating whether retinal and vascular measurements reveal broader diabetes-related microvascular changes. These research applications cannot replace diabetic eye screening, blood tests or assessment of other diabetic complications.<\/p>\n

Cardiovascular Disease<\/h2>\n

\"\"<\/p>\n

The small blood vessels in your retina may reflect aspects of your wider circulatory health. Researchers are studying whether OCT and OCTA measurements can provide information about your cardiovascular risk factors and vascular changes.<\/p>\n

These scans may help identify patterns linked to heart disease and blood-vessel damage. However, they are not currently a replacement for your cardiovascular assessment.<\/p>\n

Heart Failure<\/h2>\n

A 2025 systematic review and meta-analysis reported lower parafoveal vessel density and reduced subfoveal choroidal thickness in heart failure with reduced ejection fraction. The quantitative analysis involved six studies, with additional studies included in the wider review.<\/p>\n

The included evidence was observational and varied in patient groups and imaging methods. OCT and OCTA cannot diagnose heart failure or replace clinical examination, blood tests, ECG or cardiac imaging.<\/p>\n

High Blood Pressure<\/h2>\n

Long-term high blood pressure can affect your small blood vessels, including those supplying your retina and choroid. OCTA may help researchers measure these microvascular changes in your eyes.<\/p>\n

However, your standard blood-pressure measurements remain essential for diagnosis and monitoring. OCT findings cannot replace your clinical assessment for high blood pressure.<\/p>\n

Chronic Kidney Disease<\/h2>\n

A meta-analysis of 12 studies involving 29,340 participants found associations between chronic kidney disease and reduced average retinal thickness, macular ganglion-cell\u2013inner plexiform layer thickness and peripapillary retinal nerve fibre layer thickness.<\/p>\n

These findings do not establish a kidney-disease test because retinal thickness is also affected by age, diabetes, blood pressure, eye disease and other factors. Kidney function must still be assessed using blood tests, urine tests and other established investigations.<\/p>\n

Autoimmune and Inflammatory Diseases<\/h2>\n

Studies involving people with autoimmune or inflammatory conditions such as systemic lupus erythematosus, systemic sclerosis and Beh\u00e7et\u2019s disease have reported group-level differences in retinal and choroidal microvascular measurements. Researchers are investigating whether these findings are associated with systemic inflammation, disease activity or organ involvement.<\/p>\n