Choroidal Diseases and Disorders: Causes, Symptoms, Diagnosis, and Treatment

Title: Choroidal Diseases and Disorders: Causes, Symptoms, Diagnosis & Treatment

Description: Learn about choroidal diseases and disorders, including causes, symptoms, diagnosis, OCT findings, treatment options, and important conditions affecting the choroid.

Focus Keyword: Choroidal diseases and disorders

Secondary Keywords: choroid disorders, choroidal diseases, choroid eye disease, choroidal inflammation, choroidal neovascularization, choroidal melanoma, choroidal thickness, choroidal disorders diagnosis

Introduction

The choroid is an important vascular layer of the eye located between the retina and sclera. It contains a dense network of blood vessels that provides oxygen and nutrients to the outer retina, retinal pigment epithelium (RPE), and photoreceptors.

Although the choroid is not directly responsible for detecting light, its health is essential for maintaining normal retinal function and vision.

Choroidal diseases and disorders include a wide range of conditions involving:

• Choroidal blood vessels
• Choriocapillaris
• Choroidal stroma
• Choroidal inflammation
• Choroidal tumors
• Choroidal neovascularization
• Structural abnormalities of the choroid

Some choroidal conditions cause mild or temporary visual symptoms, while others can lead to significant and permanent vision loss if not diagnosed and treated promptly.

What Is the Choroid?

The choroid is the vascular layer of the eye situated between the retina and sclera.

From inside to outside, the posterior eye can be simplified as:

Retina → RPE/Bruch's membrane → Choroid → Sclera

The choroid is part of the uvea, together with the iris and ciliary body.

Functions of the Choroid

The choroid performs several important functions.

1. Provides Blood Supply

The choroid has one of the highest blood-flow rates of any tissue in the body relative to its metabolic requirements.

It provides oxygen and nutrients to the outer retina.

2. Supports Photoreceptors

Photoreceptors have very high metabolic demands. The choroidal circulation helps maintain their function.

3. Supports the RPE

The RPE depends on the underlying choriocapillaris for metabolic exchange.

4. Removes Metabolic Waste

Choroidal circulation contributes to the removal of metabolic products from the outer retinal/RPE complex.

5. Helps Regulate Temperature

The high blood flow through the choroid may contribute to heat regulation within the eye.

6. Absorbs Excess Light

Melanin within choroidal melanocytes helps reduce internal light scatter.

Major Types of Choroidal Diseases

Choroidal disorders can be broadly classified into several groups:

1. Inflammatory diseases

• Choroiditis
• Multifocal choroiditis
• Posterior uveitis
• Vogt-Koyanagi-Harada disease

2. Vascular disorders

• Central serous chorioretinopathy
• Choroidal ischemia
• Choroidal vascular abnormalities

3. Neovascular disorders

• Choroidal neovascularization
• Myopic CNV
• AMD-associated CNV

4. Tumors

• Choroidal melanoma
• Choroidal hemangioma
• Choroidal metastasis

5. Structural disorders

• Pachychoroid spectrum disorders
• Choroidal thinning associated with high myopia
• Choroidal thickening

1. Central Serous Chorioretinopathy

Central serous chorioretinopathy (CSC) is an important chorioretinal disorder characterized by accumulation of fluid beneath the neurosensory retina.

It is commonly associated with abnormalities of the choroid, including increased permeability and, in many cases, increased choroidal thickness.

Causes and Risk Factors

The exact mechanism is not completely understood.

Associated factors include:

• Corticosteroid exposure
• Psychological stress
• Sleep disturbances
• Certain systemic conditions
• Endogenous corticosteroid excess

Symptoms

Patients may experience:

• Blurred central vision
• Distorted vision
• Micropsia
• Reduced contrast
• Central or paracentral scotoma
• Altered color perception

Diagnosis

Important investigations include:

• OCT
• Fundus examination
• Fundus autofluorescence
• Fluorescein angiography
• Indocyanine green angiography in selected cases

Treatment

Management depends on duration, recurrence, severity, and visual impact.

Options may include:

• Observation in appropriate acute cases
• Photodynamic therapy
• Focal laser in selected cases
• Management of contributing factors
• Other treatments in selected chronic or recurrent disease

2. Choroidal Neovascularization

Choroidal neovascularization (CNV) occurs when abnormal blood vessels grow from the choroid toward or through Bruch's membrane and may extend beneath or into the retina.

CNV can occur in conditions such as:

• Age-related macular degeneration
• Pathologic myopia
• Ocular histoplasmosis
• Inflammatory chorioretinal disease
• Other causes of macular damage

Symptoms

CNV may cause:

• Sudden or progressive central vision loss
• Metamorphopsia
• Central scotoma
• Difficulty reading
• Distorted straight lines

Diagnosis

Common tests include:

• OCT
• OCT angiography
• Fluorescein angiography
• Fundus examination

Treatment

The main treatment for many forms of active macular neovascularization is intravitreal anti-VEGF therapy.

Depending on the underlying condition, other treatments may also be considered.

3. Choroidal Melanoma

Choroidal melanoma is the most common primary intraocular malignancy in adults.

It develops from melanocytes within the uveal tract, most commonly in the choroid.

Risk Factors

Risk factors can include:

• Light pigmentation
• Fair skin
• Light eye color
• Certain genetic factors
• Pre-existing choroidal nevus in some cases

Symptoms

A choroidal melanoma may be asymptomatic initially.

Possible symptoms include:

• Blurred vision
• Visual field defect
• Flashes
• Floaters
• Reduced vision
• Photopsia

Diagnosis

Evaluation may include:

• Dilated fundus examination
• Ocular ultrasonography
• OCT
• Fundus photography
• Fundus autofluorescence
• Other imaging when indicated

Treatment

Treatment depends on tumor size, location, visual potential, and other factors.

Options may include:

• Plaque brachytherapy
• Proton beam radiotherapy
• Local tumor treatment
• Enucleation in selected advanced cases
• Systemic management when metastatic disease is present

4. Choroidal Hemangioma

A choroidal hemangioma is a benign vascular tumor of the choroid.

It can be:

• Circumscribed
• Diffuse

Symptoms

Some patients have no symptoms.

Others may develop:

• Blurred vision
• Visual distortion
• Subretinal fluid
• Reduced central vision

Diagnosis

Investigations can include:

• Fundus examination
• OCT
• B-scan ultrasonography
• Fluorescein angiography
• Indocyanine green angiography

Treatment

Treatment is not always required.

When vision is affected, treatment may include:

• Photodynamic therapy
• Other focal treatments depending on the clinical situation

5. Choroidal Metastasis

The choroid is a common site for intraocular metastases because of its rich blood supply.

Choroidal metastases are secondary tumors that spread to the eye from another primary cancer.

Common primary cancers associated with choroidal metastasis include:

• Breast cancer
• Lung cancer
• Other systemic malignancies

Symptoms

Possible symptoms include:

• Blurred vision
• Visual field defects
• Flashes
• Floaters
• Metamorphopsia

Diagnosis

Diagnosis may involve:

• Fundus examination
• OCT
• Ocular ultrasonography
• Systemic evaluation
• Additional imaging

Treatment

Treatment generally focuses on the underlying systemic malignancy and may include:

• Systemic therapy
• Radiotherapy
• Local treatment when indicated

6. Choroiditis

Choroiditis refers to inflammation involving the choroid.

It may occur as part of infectious, autoimmune, or inflammatory ocular diseases.

Causes

Potential causes include:

• Autoimmune inflammation
• Infectious diseases
• Tuberculosis
• Syphilis
• Fungal infections
• Other inflammatory disorders

Symptoms

Patients may experience:

• Blurred vision
• Floaters
• Photophobia
• Scotomata
• Eye discomfort
• Reduced visual acuity

Diagnosis

Evaluation depends on the suspected cause and may include:

• Dilated fundus examination
• OCT
• Fundus autofluorescence
• Fluorescein angiography
• Laboratory testing
• Systemic evaluation

Treatment

Treatment depends strongly on the underlying cause.

Infectious inflammation requires appropriate antimicrobial therapy, whereas noninfectious inflammatory disease may require corticosteroids or immunomodulatory treatment under specialist supervision.

7. Vogt-Koyanagi-Harada Disease

Vogt-Koyanagi-Harada (VKH) disease is a multisystem inflammatory disorder that can produce significant choroidal inflammation and thickening.

Symptoms

Ocular symptoms may include:

• Blurred vision
• Photophobia
• Eye discomfort
• Serous retinal detachments
• Visual distortion

Systemic features may also occur.

Diagnosis

OCT can demonstrate marked choroidal thickening and serous retinal detachments.

Other examinations and systemic findings help establish the diagnosis.

Treatment

Treatment typically involves prompt systemic anti-inflammatory therapy, often with corticosteroids and, when appropriate, immunomodulatory treatment.

Early treatment is important to reduce the risk of chronic complications.

8. Pachychoroid Spectrum Disorders

The term pachychoroid describes a group of conditions characterized by structural changes in the choroid, often including increased choroidal thickness and dilation of larger choroidal vessels.

Conditions within this spectrum can include:

• Pachychoroid pigment epitheliopathy
• Central serous chorioretinopathy
• Pachychoroid neovasculopathy

The clinical picture varies between patients.

9. Choroidal Changes in High Myopia

High myopia can cause significant structural changes in the posterior eye.

As axial length increases, the choroid often becomes thinner.

Possible associated changes include:

• Choroidal thinning
• Chorioretinal atrophy
• Lacquer cracks
• Posterior staphyloma
• Myopic macular degeneration
• Myopic choroidal neovascularization

10. Choroidal Ischemia

Choroidal ischemia occurs when choroidal blood flow is significantly compromised.

Because the outer retina depends heavily on the choroidal circulation, severe ischemia can cause retinal and RPE dysfunction.

Potential causes include:

• Vascular disorders
• Inflammatory vasculopathy
• Systemic hypotension
• Certain vascular occlusive conditions

The clinical presentation depends on the location and severity of the vascular disturbance.

Symptoms of Choroidal Diseases

Choroidal disorders can produce a wide range of symptoms.

Common symptoms include:

Blurred Vision

Reduced visual clarity can occur when the macula or adjacent structures are affected.

Metamorphopsia

Straight lines may appear bent or distorted.

Scotoma

A patient may notice a blind or missing area in the visual field.

Flashes

Photopsia may occur with retinal or chorioretinal pathology.

Floaters

Inflammatory disease can produce vitreous cells and floaters.

Color Vision Changes

Macular or chorioretinal involvement may affect color discrimination.

Reduced Contrast

Some patients may experience reduced contrast sensitivity.

Photophobia

Inflammatory eye diseases can produce light sensitivity.

Causes and Risk Factors of Choroidal Disorders

Different diseases have different causes.

Important risk factors and mechanisms include:

Age

Age-related structural and vascular changes can affect the choroid.

Myopia

High myopia can cause choroidal thinning and degenerative changes.

Inflammation

Autoimmune and infectious diseases can involve the choroid.

Vascular Abnormalities

Changes in choroidal circulation can contribute to disease.

Corticosteroid Exposure

Corticosteroid exposure is an important risk factor for central serous chorioretinopathy.

Cancer

Systemic malignancies can metastasize to the choroid.

Genetic Factors

Some inherited disorders can affect choroidal and retinal tissues.

How Are Choroidal Diseases Diagnosed?

Diagnosis begins with a detailed ocular examination.

A clinician may use several investigations depending on the suspected condition.

1. Dilated Fundus Examination

A dilated examination allows direct visualization of:

• Retina
• Macula
• Optic nerve
• Choroidal abnormalities visible through the retina

2. Optical Coherence Tomography

OCT is one of the most important imaging techniques for evaluating chorioretinal disorders.

It can demonstrate:

• Choroidal thickness
• Subretinal fluid
• RPE abnormalities
• Retinal edema
• Pigment epithelial detachments
• Choroidal lesions

3. OCT Angiography

OCT angiography (OCTA) provides noninvasive visualization of blood-flow-related vascular networks.

It can help evaluate:

• Choroidal neovascularization
• Macular neovascularization
• Retinal vascular abnormalities

4. Fluorescein Angiography

Fluorescein angiography helps evaluate retinal and chorioretinal vascular leakage and circulation.

It is particularly useful in selected cases of:

• CNV
• CSC
• Retinal vascular disease
• Inflammatory disease

5. Indocyanine Green Angiography

Indocyanine green angiography (ICGA) is especially useful for evaluating the choroidal circulation because the dye's properties allow better visualization of deeper vascular structures than fluorescein in many situations.

It can be valuable in:

• CSC
• Pachychoroid disorders
• Choroidal inflammatory conditions
• Some choroidal tumors

6. Ocular Ultrasonography

B-scan ultrasonography is particularly useful for evaluating choroidal masses.

It can help assess:

• Tumor size
• Lesion location
• Internal characteristics
• Relationship with surrounding structures

It is especially useful when the ocular media are opaque.

7. Fundus Autofluorescence

Fundus autofluorescence can provide information about RPE health and metabolic changes.

It can be useful in:

• CSC
• Inflammatory chorioretinal disease
• Retinal degenerative disease

8. Systemic Investigations

Some choroidal diseases are associated with systemic disease.

Depending on clinical suspicion, investigations may include:

• Blood tests
• Infectious disease testing
• Autoimmune evaluation
• Imaging studies
• Cancer evaluation

The exact tests depend on the patient's presentation.

Treatment of Choroidal Diseases

Treatment depends entirely on the underlying disorder.

There is no single treatment for all choroidal diseases.

Anti-VEGF Therapy

Anti-VEGF injections are widely used for conditions involving abnormal choroidal or macular neovascularization.

They reduce abnormal vascular leakage and suppress pathological neovascular activity.

They are commonly used for:

• Neovascular AMD
• Myopic CNV
• Other forms of macular neovascularization

Photodynamic Therapy

Photodynamic therapy can be particularly useful for selected choroidal disorders, including:

• Chronic/recurrent CSC
• Some choroidal vascular lesions

It uses a photosensitizing drug followed by activation with a specific wavelength of light.

Corticosteroids

Corticosteroids may be used for appropriate noninfectious inflammatory choroidal diseases.

They can be administered by:

• Topical routes in selected anterior conditions
• Periocular routes
• Intravitreal routes
• Systemic routes

The choice depends on the location and severity of inflammation.

Immunomodulatory Therapy

Patients with chronic or severe immune-mediated ocular inflammation may require steroid-sparing immunomodulatory therapy.

Treatment should be supervised by an ophthalmologist, often with appropriate medical collaboration.

Radiation Therapy

Radiation can be used for certain choroidal tumors.

Examples include:

• Choroidal melanoma
• Selected choroidal metastases

Treatment selection depends on tumor characteristics and the patient's overall condition.

Surgical Treatment

Surgery may be required for selected tumors or advanced complications.

For example, enucleation may be considered for some large or advanced intraocular tumors when eye-conserving treatments are unsuitable.

Observation

Not every choroidal abnormality requires immediate treatment.

Small asymptomatic lesions or some acute conditions may be monitored with:

• Fundus photography
• OCT
• Ultrasound
• Regular clinical examinations

The decision depends on the specific diagnosis.

Choroidal Diseases and Vision Loss

The impact on vision depends on:

• Location of the lesion
• Size
• Duration
• Involvement of the macula
• Degree of inflammation
• Presence of subretinal fluid
• Vascular involvement
• Treatment response

A small peripheral choroidal lesion may have little effect on vision, whereas a small lesion directly beneath the fovea may significantly affect central vision.

Choroidal Diseases Affecting the Macula

The macula is particularly important because it is responsible for detailed central vision.

Choroidal diseases affecting the macula may cause:

• Central blur
• Distortion
• Central scotoma
• Reading difficulty
• Reduced visual acuity

Examples include:

• CSC
• CNV
• AMD-related choroidal changes
• Myopic CNV
• Some inflammatory disorders

Choroidal Thickness and Disease

Choroidal thickness can be measured using OCT.

Changes in thickness may provide useful information in certain diseases.

Choroidal thickening may occur in:

• CSC
• Pachychoroid spectrum disorders
• VKH and some inflammatory conditions

Choroidal thinning may occur in:

• High myopia
• Aging
• Some chronic degenerative conditions

However, choroidal thickness is not a standalone diagnostic test. It must be interpreted alongside clinical findings and other imaging.

Can Choroidal Diseases Be Prevented?

Not all choroidal diseases can be prevented because some are related to genetics, inflammation, aging, or cancer.

However, several healthy practices can help protect overall ocular health.

Regular Eye Examinations

Routine examinations can identify asymptomatic abnormalities.

Control Systemic Diseases

Good control of systemic vascular and metabolic conditions supports ocular health.

Avoid Unnecessary Corticosteroid Use

Corticosteroids should be used only when medically indicated and under appropriate supervision.

Protect Against UV Exposure

Appropriate UV protection can help protect ocular tissues from cumulative ultraviolet exposure.

Manage Myopia

Early detection and appropriate management of progressive/high myopia may reduce the risk of severe myopic complications.

Seek Prompt Care for New Visual Symptoms

Sudden visual changes should not be ignored.

Warning Signs That Require Urgent Eye Evaluation

Some symptoms may indicate serious retinal or choroidal disease.

Seek urgent ophthalmic assessment for:

• Sudden loss of vision
• New central distortion
• Sudden increase in floaters
• Flashes of light
• A new visual field defect
• A dark curtain or shadow in vision
• Rapidly worsening vision
• New unexplained central scotoma

Choroidal Disease vs Retinal Disease

Because the retina and choroid are closely connected, distinguishing between them can sometimes be difficult.

Many diseases, however, involve both retina and choroid and are therefore better described as chorioretinal disorders.

Frequently Asked Questions

What are choroidal diseases?

Choroidal diseases are conditions affecting the vascular and pigmented layer between the retina and sclera. They include inflammatory, vascular, neoplastic, neovascular, and structural disorders.

What is the most common choroidal disease?

There is no single condition that can universally be called the most common choroidal disease. The frequency depends on the population and clinical setting. CSC, choroidal neovascularization, and various age- or myopia-related choroidal changes are commonly encountered.

Can choroidal disease cause blindness?

Yes. Severe or untreated choroidal disease can cause significant and sometimes permanent vision loss, particularly when the macula or optic structures become involved.

Is choroidal melanoma cancer?

Yes. Choroidal melanoma is a malignant intraocular tumor arising from melanocytes of the uveal tract.

Can OCT detect choroidal disease?

OCT is highly useful for evaluating many choroidal disorders, particularly choroidal thickness, subretinal fluid, RPE changes, and some lesions.

What disease causes a thick choroid?

Central serous chorioretinopathy and pachychoroid-spectrum disorders are commonly associated with choroidal thickening. Inflammatory conditions such as VKH can also cause marked choroidal thickening.

What causes a thin choroid?

High myopia and aging are important associations. Choroidal thinning may also occur in some chronic degenerative conditions.

Can choroidal disease be treated?

Yes, but treatment depends on the diagnosis. Options may include observation, anti-VEGF injections, photodynamic therapy, corticosteroids, immunomodulatory therapy, radiotherapy, or surgery.

Is choroidal thickness the same as retinal thickness?

No. Retinal thickness measures the neural retinal tissue, whereas choroidal thickness generally measures the distance between the RPE/Bruch's membrane complex and the scleral boundary.

Easy Mnemonics for Choroidal Diseases

CSC = Thick Choroid

Central

Serous

Chorioretinopathy

Think:

CSC → Thick choroid + fluid

CNV = New Vessels

Choroidal

Neovascularization

V = Vessels

Think:

CNV → Abnormal new vessels

Choroid = C for Circulation

C = Choroid → Circulation

The choroid has an extensive vascular network that supports the outer retina.

One-Minute Revision

Choroid

↓

Vascular layer

↓

Supports outer retina

↓

Diseases can be:

Inflammatory + Vascular + Neovascular + Tumorous + Structural

Important diseases

CSC → thick choroid + subretinal fluid

CNV → abnormal choroidal vessels

Melanoma → malignant choroidal tumor

Choroiditis → inflammation

VKH → marked choroidal thickening

High myopia → choroidal thinning

Modern imaging techniques such as OCT, OCT angiography, fluorescein angiography, indocyanine green angiography, fundus autofluorescence, and ocular ultrasonography have significantly improved the diagnosis and monitoring of choroidal disorders.

The most important clinical principle is that treatment depends on the underlying cause. Anti-VEGF therapy is important for many neovascular disorders, photodynamic therapy has an important role in selected conditions such as chronic CSC, inflammatory diseases may require anti-inflammatory or immunomodulatory treatment, and choroidal tumors require specialized oncologic management.

Early recognition of symptoms such as sudden vision loss, new distortion, flashes, floaters, or visual field defects can be critical because some choroidal and chorioretinal disorders can cause irreversible vision loss if diagnosis and treatment are delayed.

Conclusion

Choroidal diseases and disorders represent a diverse group of ocular conditions involving the vascular and pigmented layer between the retina and sclera. Because the choroid provides critical metabolic support to the outer retina and RPE, abnormalities in this tissue can have significant consequences for vision.

Important choroidal conditions include central serous chorioretinopathy, choroidal neovascularization, choroidal melanoma, choroidal hemangioma, choroidal metastasis, choroiditis, Vogt-Koyanagi-Harada disease, pachychoroid-spectrum disorders, and myopia-related choroidal changes.