Scleral Inflammation and Eye Pain: Scleritis Causes, Complications, Diagnosis, and Treatment

Table of Contents

What Is Scleral Inflammation?

Scleral inflammation refers to inflammation involving the sclera, the dense connective-tissue outer coat of the eye.

The sclera forms approximately the posterior five-sixths of the fibrous tunic of the eyeball. It provides structural support, protection, shape, attachment for extraocular muscles, and mechanical support around the posterior eye.

Inflammation of the sclera is known as scleritis. Because the sclera is relatively deep and contains sensory nerve fibers, inflammation can produce substantial pain.

What Is Scleritis?

Scleritis is a potentially serious inflammatory disease involving the scleral tissue. It can affect the anterior sclera, posterior sclera, a localized portion, or a large portion. Scleritis may be associated with systemic inflammatory disease, infection, trauma, or previous ocular surgery, although some cases remain idiopathic.

Why Does Scleritis Cause Severe Eye Pain?

The sclera receives sensory innervation, including fibers associated with the ophthalmic division of the trigeminal nerve. Inflammation can stimulate these sensory pathways, resulting in deep aching pain, severe tenderness, pain around the eye, pain radiating to the forehead or face, pain with eye movement, and night-time worsening in some cases.

Clinical clue: Red eye + severe deep pain = think about scleritis and other serious ocular conditions.

Scleritis vs Episcleritis

A major diagnostic distinction is between scleritis and episcleritis.

Episcleritis

Inflammation affects the superficial episcleral tissue. Usually mild discomfort, bright redness, vision preserved, self-limiting.

Scleritis

Inflammation affects deeper scleral tissue. Usually severe deep pain, deeper redness, tenderness, possible reduction in vision, greater risk of complications.

Causes of Scleritis

Scleritis has multiple possible causes. The major categories include:

1. Autoimmune and inflammatory disease
2. Infectious disease
3. Trauma
4. Previous ocular surgery
5. Idiopathic disease

1. Autoimmune Causes of Scleritis

Systemic inflammatory and autoimmune diseases are important associations. Examples include rheumatoid arthritis, granulomatosis with polyangiitis, systemic lupus erythematosus, relapsing polychondritis, polyarteritis nodosa, inflammatory bowel disease, and other systemic vasculitic disorders.

Rheumatoid Arthritis and Scleritis

Rheumatoid arthritis is one of the classic systemic diseases associated with scleritis. When a patient presents with unexplained scleritis, a history of joint pain, swelling, morning stiffness, or known autoimmune disease may be clinically relevant.

2. Infectious Scleritis

Not all scleritis is autoimmune. Infectious scleritis can occur and may be associated with bacterial infections, herpes zoster, syphilis, tuberculosis, and fungal infections in selected cases. This distinction is extremely important because treatment for infectious scleritis is different from treatment for noninfectious autoimmune inflammation.

Important clinical principle: Do not assume every case of scleritis is autoimmune. An infectious cause must be considered when the clinical history or examination suggests infection.

3. Trauma-Associated Scleritis

Scleral inflammation may occur after blunt ocular trauma, penetrating injury, foreign-body injury, or surgical trauma. Trauma can damage the sclera directly and trigger secondary inflammatory responses.

4. Postsurgical Scleritis

Scleritis can occasionally develop after ocular surgery. Possible associations include local tissue injury, inflammation, infection, and immune-mediated responses.

5. Idiopathic Scleritis

Sometimes extensive evaluation fails to identify an underlying systemic or infectious cause. Such cases are described as idiopathic scleritis. Even idiopathic scleritis can be severe and may require treatment.

Types of Scleritis

Scleritis is broadly classified into:

Anterior scleritis

Inflammation affects the anterior portion of the sclera. Further classified as diffuse, nodular, necrotizing with inflammation, and necrotizing without inflammation.

Posterior scleritis

Inflammation affects the sclera behind the equator of the eyeball.

Anterior Scleritis

Anterior scleritis is the form that is most readily visible during external and slit-lamp examination.

Common symptoms

• Severe eye pain
• Deep redness
• Tenderness
• Photophobia
• Tearing
• Blurred vision

The redness may appear deep red or violaceous.

Diffuse Anterior Scleritis

In diffuse scleritis, a relatively broad area of scleral tissue becomes inflamed. The eye may appear diffusely red, deeply congested, and tender.

Nodular Anterior Scleritis

In nodular scleritis, inflammation is concentrated in a localized region. A patient may develop a localized red area, a raised or firm scleral region, significant tenderness, and deep pain.

Necrotizing Scleritis

Necrotizing scleritis is a severe and potentially destructive form of scleral inflammation. It can result in scleral necrosis, scleral thinning, tissue destruction, structural weakening, risk of perforation, and visual complications. Necrotizing scleritis may be associated with systemic vasculitic or autoimmune disease.

Posterior Scleritis

Posterior scleritis occurs behind the equator of the eyeball. Because the posterior sclera cannot be easily visualized externally, diagnosis can be more challenging.

Symptoms may include:

• Deep eye pain
• Headache
• Blurred vision
• Reduced vision
• Pain with eye movement
• Photophobia

Posterior scleritis may occur with minimal visible external redness.

Posterior Scleritis and Retinal Findings

Inflammation of the posterior sclera can affect nearby structures. Possible findings include choroidal effusion, exudative retinal detachment, optic disc swelling, choroidal thickening, and macular changes.

The T-Sign in Posterior Scleritis

One of the classic diagnostic findings is the T-sign on B-scan ultrasonography. It occurs because inflammation causes posterior scleral thickening and fluid in Tenon's space. The resulting ultrasound appearance produces the characteristic T-shaped configuration.

NEET PG / INICET high-yield point: T-sign → posterior scleritis

Symptoms of Scleritis

The clinical presentation can vary, but common symptoms include:

Severe eye pain

Usually deep and aching.

Redness

The eye may become intensely red or violaceous.

Tenderness

The sclera may be very sensitive.

Photophobia

Light sensitivity can occur.

Tearing

Reflex lacrimation may be present.

Blurred vision

May occur when the sclera or adjacent ocular structures are affected.

Pain with eye movement

May occur, particularly in posterior disease.

Clinical Signs of Scleritis

A clinician may observe deep scleral congestion, violaceous redness, scleral tenderness, dilated episcleral vessels, scleral edema, nodules, scleral thinning, areas of necrosis, associated corneal disease, and anterior chamber inflammation.

Does Scleritis Affect Vision?

Scleritis itself may or may not initially reduce vision. However, vision can become impaired if the inflammation affects nearby structures. Possible causes of visual reduction include keratitis, uveitis, glaucoma, cataract, choroidal effusion, retinal detachment, optic nerve involvement, and macular involvement.

Reduced vision in a patient with a painful red eye is an important warning sign.

Diagnosis of Scleritis

Diagnosis requires a detailed ocular examination. The evaluation may include:

1. Visual acuity

Establishes whether vision is affected.

2. Slit-lamp examination

Evaluates conjunctiva, episclera, sclera, cornea, anterior chamber, and iris.

3. Assessment of scleral tenderness

The degree of pain and tenderness can help distinguish deeper inflammation from superficial disease.

4. Ocular motility

Pain associated with movement may provide additional clinical information.

5. Fundus examination

Important when vision is reduced or posterior involvement is suspected.

B-Scan Ultrasonography

B-scan ultrasonography is particularly useful for suspected posterior scleritis. It can demonstrate posterior scleral thickening, fluid in Tenon's space, choroidal effusion, and exudative retinal detachment. The classic T-sign can support the diagnosis.

OCT in Scleral Inflammation

Optical coherence tomography (OCT) can help evaluate associated changes in the retina, choroid, optic nerve, and macula.

Laboratory Evaluation

Laboratory investigations should be guided by age, medical history, symptoms, ocular findings, recurrent disease, and suspicion of autoimmune or infectious disease. Possible tests may include CBC, ESR, CRP, rheumatoid factor, anti-CCP, ANA, ANCA, syphilis testing, tuberculosis evaluation, and other targeted investigations.

Why Screen for Systemic Disease?

Scleritis can sometimes be the first clinical sign of a systemic inflammatory condition. A patient may have ocular inflammation before receiving a diagnosis of an autoimmune disorder. Clinicians may ask about joint pain, morning stiffness, skin lesions, respiratory symptoms, sinus disease, gastrointestinal symptoms, cartilage inflammation, and previous autoimmune diagnoses.

Differential Diagnosis of Scleral Inflammation

A painful red eye has many possible causes. Important differential diagnoses include episcleritis, conjunctivitis, keratitis, corneal ulcer, anterior uveitis, acute angle-closure glaucoma, orbital inflammation, and trauma.

Scleritis vs Episcleritis (Comparison Table)

Feature	Episcleritis	Scleritis
Tissue involved	Episclera	Sclera
Depth	Superficial	Deep
Pain	Mild	Severe
Redness	Bright red	Deep red/violaceous
Vision	Usually normal	May be reduced
Tenderness	Mild	Marked
Systemic association	Possible	Important
Complications	Uncommon	Potentially serious
Treatment	Often supportive	Usually systemic therapy

Easy memory: Episcleritis = superficial and mild. Scleritis = deep and painful.

Scleritis vs Conjunctivitis

Conjunctivitis commonly produces redness, irritation, discharge, and grittiness. Severe deep pain is not typical of uncomplicated conjunctivitis. Scleritis more commonly produces deep pain, tenderness, violaceous redness, photophobia, and potential visual reduction. Therefore, a very painful red eye should not automatically be labeled conjunctivitis.

Complications of Scleritis

Scleritis can produce complications involving both the sclera and adjacent ocular structures.

1. Scleral thinning – Inflammatory destruction may weaken the sclera.
2. Scleral necrosis – Severe inflammation may cause tissue death.
3. Corneal involvement – Inflammation can extend to the peripheral cornea.
4. Uveitis – Inflammation may involve the uveal tract.
5. Glaucoma – Inflammatory changes may contribute to elevated intraocular pressure.
6. Cataract – Long-standing inflammation or corticosteroid treatment may contribute.
7. Choroidal effusion – Particularly relevant in posterior scleritis.
8. Exudative retinal detachment – Fluid accumulation can separate the neurosensory retina.
9. Optic nerve involvement – Posterior inflammation may affect the optic nerve region.
10. Vision loss – Severe or complicated scleritis can cause permanent visual impairment.

Treatment of Scleritis

Treatment depends on the underlying cause and severity. Management may involve systemic anti-inflammatory treatment, corticosteroids, immunomodulatory therapy, antimicrobial therapy when infection is identified, treatment of underlying systemic disease, and surgical management for selected structural complications.

NSAIDs in Scleritis

Nonsteroidal anti-inflammatory drugs (NSAIDs) may be used in appropriate cases of noninfectious scleritis. They can reduce pain, inflammation, and tenderness.

Corticosteroids

Corticosteroids may be required when inflammation is more severe or does not respond adequately to NSAIDs. They may be administered systemically depending on the clinical situation.

Immunomodulatory Therapy

Patients with severe scleritis, necrotizing scleritis, recurrent disease, steroid-dependent disease, or associated systemic autoimmune disease may require immunomodulatory therapy. Treatment is individualized and may involve collaboration between ophthalmology and other medical specialists.

Treatment of Infectious Scleritis

If the scleral inflammation is caused by an infection, treatment must target the specific organism. Depending on the cause, management may involve antibacterial, antiviral, or antifungal therapy, and treatment of systemic infection.

Important principle: Infectious scleritis should not simply be treated as autoimmune scleritis.

Treatment of the Underlying Systemic Disease

If scleritis is associated with an autoimmune condition, controlling the systemic disease can be an important part of long-term management.

Surgical Management

Surgery is not the first-line treatment for most inflammatory scleritis. However, surgery may occasionally be considered for structural complications such as severe scleral thinning, structural weakness, perforation, and associated ocular complications.

Can Scleritis Be Prevented?

There is no guaranteed method to prevent idiopathic scleritis. However, patients with known systemic inflammatory diseases can reduce complications through regular medical follow-up, appropriate control of systemic inflammation, early evaluation of ocular symptoms, and prompt treatment of recurrent inflammation.

When Should You Seek Urgent Eye Care?

A painful red eye should be evaluated promptly when associated with severe or worsening pain, reduced vision, significant photophobia, marked tenderness, corneal opacity, abnormal pupil, pain with eye movement, recent eye trauma, persistent redness, or severe headache/systemic symptoms.

Scleral Inflammation and Optometry

Optometrists have an important role in identifying suspicious cases of scleral inflammation. Recognizing deep ocular redness, violaceous discoloration, severe tenderness, scleral nodules, scleral thinning, associated corneal changes, anterior chamber inflammation, and reduced visual acuity can help prevent serious complications.

Scleritis and Systemic Autoimmune Disease

A key concept in ophthalmology is: The eye can sometimes provide an early clue to systemic disease. Important associations include rheumatoid arthritis, granulomatosis with polyangiitis, relapsing polychondritis, systemic lupus erythematosus, polyarteritis nodosa, and inflammatory bowel disease.

Clinical Approach to Scleral Inflammation

1. Assess visual acuity – Is vision normal or reduced?
2. Assess pain – Is it mild irritation or severe deep pain?
3. Examine the redness – Is it superficial or deep?
4. Examine the cornea – Look for infiltrate, ulcer, edema, other abnormalities.
5. Examine the anterior chamber – Look for inflammatory cells and flare.
6. Consider posterior disease – If pain or visual symptoms suggest posterior involvement, imaging may be necessary.
7. Investigate systemic disease when appropriate – Consider autoimmune or infectious causes based on the clinical picture.

Easy Mnemonic for Scleritis

“SCLERITIS = Severe, Deep, Systemic, Serious”

S – Severe pain
C – Can cause complications
L – Loss of vision possible
E – Eye appears deeply red
R – Rheumatoid arthritis association
I – Inflammation of sclera
T – T-sign in posterior disease
I – Infectious causes possible
S – Systemic evaluation may be needed

Frequently Asked Questions About Scleritis

What is scleritis?

Scleritis is inflammation of the deeper scleral tissue and is an important cause of a painful red eye.

What is the main symptom of scleritis?

Severe, deep ocular pain is one of the most characteristic symptoms.

What causes scleritis?

Causes include autoimmune disease, systemic inflammatory disorders, infection, trauma, surgery, and idiopathic disease.

Is scleritis associated with rheumatoid arthritis?

Yes. Rheumatoid arthritis is a classic systemic association.

What is posterior scleritis?

Posterior scleritis is inflammation involving the posterior sclera and can cause deep pain, visual symptoms, choroidal effusion, and exudative retinal detachment.

What is the T-sign?

The T-sign is a characteristic B-scan ultrasonography finding associated with posterior scleritis, reflecting fluid in Tenon's space around a thickened posterior sclera.

Can scleritis cause blindness?

Severe or complicated scleritis can cause significant visual loss, particularly when associated with necrosis or involvement of adjacent ocular structures.

Is scleritis the same as episcleritis?

No. Episcleritis is superficial and generally mild, while scleritis is deeper, more painful, and potentially vision-threatening.

Can scleritis be caused by infection?

Yes. Infectious scleritis can occur and requires treatment directed at the underlying infectious organism.

Conclusion

Scleral inflammation and scleritis are important causes of painful red eye and should be distinguished from more superficial conditions such as episcleritis. Scleritis involves deeper scleral tissue and is commonly characterized by severe deep ocular pain, significant redness, tenderness, and sometimes reduced vision.

The disease can be associated with systemic autoimmune disorders such as rheumatoid arthritis and systemic vasculitis, but infectious, traumatic, postsurgical, and idiopathic causes also occur.

Scleritis may be classified into anterior and posterior forms, with anterior disease including diffuse, nodular, and necrotizing patterns. Posterior scleritis can be difficult to recognize clinically, and B-scan ultrasonography with the characteristic T-sign can be particularly helpful.

Treatment depends on the cause and severity and may involve NSAIDs, corticosteroids, immunomodulatory therapy, or antimicrobial treatment when infection is identified. Severe disease can cause scleral thinning, necrosis, keratitis, uveitis, glaucoma, choroidal effusion, retinal detachment, and vision loss.

The most important clinical takeaway:

A red eye with severe, deep pain should never be dismissed as simple conjunctivitis.

Recognizing the difference between episcleritis, scleritis, keratitis, uveitis, glaucoma, and other causes of painful red eye is essential for timely diagnosis, appropriate referral, and prevention of vision-threatening complications.