Acute Retinal Pigment Epitheliitis (ARPE), sometimes called Krill’s disease, is a rare, self‐limiting inflammation of the retinal pigment epithelium (RPE). The RPE is a thin layer of cells just beneath the light‐sensing photoreceptors in the back of your eye. These cells help nourish photoreceptors, absorb stray light, and maintain a healthy visual environment. In ARPE, the RPE becomes temporarily disrupted, causing sudden changes in vision such as blurred spots or mild visual distortion. Symptoms usually appear quickly, often over days, and then resolve on their own over weeks to months without long‐term damage. Because it is uncommon and heals spontaneously, ARPE may be underdiagnosed. Early recognition and supportive care can help reassure patients as they recover.
Acute Retinal Pigment Epitheliitis (ARPE), also known as Krill’s disease, is a rare, self-limiting inflammatory disorder of the outer retina and retinal pigment epithelium (RPE). It most often affects healthy young adults, presenting suddenly with mild to moderate visual disturbances—typically decreased central vision or a central “blind spot” (scotoma). On examination, small, discrete, round pigment clumps encircled by pale halos appear in the macula, with minimal to no signs of inflammation elsewhere in the eye. Fluorescein angiography demonstrates early transmission hyperfluorescence of the affected RPE without leakage, and spectral-domain OCT reveals focal hyperreflectivity at the level of the RPE and photoreceptor outer segments, often extending into the outer nuclear layer PubMedNature.
Pathophysiology
In ARPE, the exact trigger remains unclear. Researchers believe that a brief inflammatory reaction—possibly due to a mild viral infection or an autoimmune flare—disturbs the normal interaction between the RPE and photoreceptors. When the RPE is inflamed, its ability to pump fluid, recycle photopigments, and maintain the light‐absorbing barrier is impaired. This leads to localized areas where the RPE appears mottled or granular on imaging. Photoreceptors overlying these spots then send abnormal signals, translated by the brain as scotomas (dark spots) or metamorphopsia (visual distortion). As inflammation calms, RPE cells recover and photoreceptors restore function, leading to gradual symptom resolution.
Types of Acute Retinal Pigment Epitheliitis
1. Classic Unilateral ARPE
Most commonly, ARPE affects only one eye. Patients notice sudden onset of a single blurry spot or mild distortion in one visual field. This classic form usually resolves within six to eight weeks.
2. Bilateral ARPE
In some cases, both eyes develop inflammation simultaneously or sequentially. Bilateral ARPE may cause more noticeable visual disturbances but follows a similar healing pattern.
3. Recurrent ARPE
Although rare, a small subset of patients experiences repeat episodes. Symptoms return weeks to months after the first episode, often with less severity and shorter duration.
4. Secondary ARPE
Occasionally, ARPE appears alongside systemic conditions—such as autoimmune diseases or following viral infections. In these cases, RPE inflammation may be part of a broader inflammatory response.
Causes of ARPE
Idiopathic Inflammation
In many patients, no clear cause emerges. The RPE simply becomes inflamed for unknown reasons, possibly from a transient immune trigger.Viral Infections
Mild viral illnesses—such as a common cold or flu—may provoke a brief immune reaction in the eye, inflaming the RPE.Autoimmune Reactivity
An overactive immune system targeting RPE cells can spark inflammation, even without a systemic autoimmune disease.Systemic Viral Illness
More serious viral infections like Epstein–Barr virus (EBV) or cytomegalovirus (CMV) have occasionally coincided with ARPE.Drug‐Induced Reactions
Certain medications—especially those processed in the eye—might trigger an RPE inflammatory response as a side effect.Phototoxic Injury
Excessive exposure to intense light (e.g., welding arcs, strong sunlight without protection) can damage RPE cells, leading to inflammation.Solar Retinopathy
Intentional or accidental gazing at the sun without UV protection can inflame and injure the RPE.Trauma
Blunt force or sudden jarring of the head may cause micro‐damage to the retinal layers, including the RPE.Uveitis Association
Inflammation of the uvea (middle eye layer) can spread to the RPE in some uveitis subtypes.Vasculitis
Inflammatory blood vessel diseases may reduce blood flow to the RPE, resulting in secondary inflammation.Metabolic Disorders
Rare metabolic imbalances—such as in mitochondrial disease—can stress RPE cells, making them prone to inflammation.Genetic Predisposition
Although no single gene has been pinpointed, some individuals may carry variants making their RPE more sensitive to immune triggers.Toxin Exposure
Certain industrial or environmental toxins can accumulate in the RPE, eliciting an inflammatory response.Nutritional Deficiencies
Severe lack of antioxidants (like vitamins C and E) may impair RPE cell health, leaving them vulnerable to inflammation.Idiopathic Recurrence
In recurrent ARPE, the RPE briefly flares for unknown reasons, possibly due to lingering low‐level immune activity.
Symptoms of ARPE
Central Scotoma
A dark or gray spot in the center of vision, often ringed by normal seeing areas, makes reading and recognizing faces harder.Blurred Vision
Objects may appear out of focus or “cloudy,” especially when trying to read fine print.Metamorphopsia
Straight lines—like door frames—may look wavy or bent, reflecting disturbed photoreceptor signaling.Photopsia
Brief flashes of light or flickers can occur as inflamed RPE cells misfire.Dyschromatopsia
Colors may look washed out or slightly altered when passing through the affected retinal area.Micropsia
Objects may appear smaller than they are, as the brain misinterprets signals from the damaged RPE.Floaters
Small shadows or specks drifting across the field of vision can accompany inflammation.Mild Eye Discomfort
A faint ache or pressure behind the eye may be reported, though pain is usually minimal.Photophobia
Bright light can feel uncomfortable, causing some patients to squint or wear sunglasses indoors.Delayed Dark Adaptation
Difficulty adjusting from bright to dim environments can occur until RPE function normalizes.
Diagnostic Tests
Physical Exam Tests
Visual Acuity Measurement
Using a standardized chart, the eye doctor checks how clearly each eye sees at a distance. ARPE often reduces central vision in the affected eye.Pupillary Light Reflex
By shining a light in each eye, the doctor observes pupil constriction. In ARPE, the reflex is usually normal, helping rule out optic nerve problems.Intraocular Pressure Measurement
A gentle puff of air or handheld tonometer assesses eye pressure. Normal pressure helps distinguish ARPE from glaucomatous conditions.
Manual Tests
Amsler Grid Test
Patients stare at a grid of straight lines and report any waviness or missing areas. Distorted or missing lines pinpoint the scotoma location.Slit‐Lamp Biomicroscopy
A specialized microscope with a bright beam allows close inspection of the retina. The doctor may see granular changes in the RPE layer.Direct Ophthalmoscopy
Using a handheld light and lens, the physician examines the retina’s surface. Patches of RPE irregularity appear as small, yellowish lesions.
Lab and Pathological Tests
Complete Blood Count (CBC)
Checks for signs of systemic infection or inflammation. A mildly elevated white blood cell count can support an inflammatory cause.Erythrocyte Sedimentation Rate (ESR) and C‐Reactive Protein (CRP)
These markers rise with inflammation anywhere in the body. Elevated values suggest a systemic inflammatory trigger for ARPE.Viral Serology
Blood tests for common viruses (e.g., herpes, varicella) help identify recent infections that might have sparked eye inflammation.Autoimmune Panel
Tests for antinuclear antibodies (ANA) and rheumatoid factor can reveal hidden autoimmune disorders affecting the RPE.Syphilis Serology
Because syphilis can mimic many retinal diseases, screening with RPR or VDRL is often performed to exclude this treatable cause.
Electrodiagnostic Tests
Full‐Field Electroretinography (ERG)
Measures the electrical response of the entire retina to light flashes. In ARPE, ERG is usually normal or mildly reduced, confirming localized RPE disruption.Multifocal ERG (mfERG)
Records electrical signals from multiple small retinal areas. It can map the precise area of reduced function matching the patient’s scotoma.Visual Evoked Potential (VEP)
Though primarily for optic nerve testing, VEP ensures signals from the retina reach the brain normally, helping exclude optic neuritis.Electrooculography (EOG)
Assesses RPE health by measuring changes in electrical potential as the eyes move. A reduced Arden ratio (light vs dark) suggests RPE dysfunction.
Imaging Tests
Optical Coherence Tomography (OCT)
A noninvasive scan that generates cross‐sectional images of the retina. OCT reveals small elevations or disruptions in the RPE and outer retina.Fundus Autofluorescence (FAF)
Uses the eye’s natural fluorescence to show RPE metabolism. In ARPE, affected areas may appear as dark or bright spots depending on RPE health.Fluorescein Angiography (FA)
After injecting a fluorescent dye, a series of rapid‐fire photos tracks blood flow through retinal vessels. ARPE lesions often show mild blockage with late staining.Indocyanine Green Angiography (ICGA)
Similar to FA but uses a different dye that highlights deeper choroidal vessels. It helps distinguish ARPE from deeper choroidal inflammation.Fundus Photography
High‐resolution color photos document RPE lesions. Serial images over weeks track lesion fading, helping confirm the self‐resolving nature of ARPE.
Non-Pharmacological Treatments
Below are 20 supportive and rehabilitative approaches—spanning physiotherapy/electrotherapy, exercise, mind-body techniques, and self-management education—that may help maintain retinal health, support visual recovery, or alleviate symptoms in ARPE.
A. Physiotherapy & Electrotherapy Therapies
Transpalpebral Electrical Stimulation
Description & Mechanism: Delivers low-current pulses across closed eyelids to stimulate RPE cells and retinal neurons. Animal and early human studies suggest it may promote neurotrophic factor release and reduce inflammation.
Purpose: Potentially accelerates recovery of photoreceptor integrity. FrontiersNon-Invasive Electrical Stimulation (ES)
Description & Mechanism: Electrodes placed on the forehead and temples deliver microampere currents, enhancing retinal blood flow and exerting neuroprotective, anti-inflammatory effects.
Purpose: May preserve or restore visual function in inflammatory retinal conditions. BioMed CentralPhotobiomodulation (PBM)
Description & Mechanism: Low-level visible to near-infrared light (600–1,000 nm) applied externally to the eye, modulating mitochondrial function, reducing oxidative stress, and curbing inflammation.
Purpose: Supports RPE and photoreceptor health; under investigation in retinal degenerations. PentaVisionLow-Level Light Therapy (LLLT)
Description & Mechanism: Similar to PBM, uses specific wavelengths (e.g., 670 nm) to stimulate cytochrome c oxidase in mitochondria.
Purpose: Aims to speed lesion resolution and photoreceptor recovery. PentaVisionBiofeedback Visual Rehabilitation
Description & Mechanism: Uses real-time feedback (microperimetry) to train fixation stability and enhance remapping of central visual field.
Purpose: Improves use of unaffected retinal areas for clearer vision. TVSTTranscranial Direct Current Stimulation (tDCS)
Description & Mechanism: Delivers weak electrical currents through scalp electrodes to modulate visual cortex excitability.
Purpose: May enhance visual processing post-retinal injury.Magnetotherapy
Description & Mechanism: Applies pulsed electromagnetic fields near the eye, theorized to boost microcirculation and reduce inflammation.
Purpose: Supports retinal recovery, though clinical evidence is limited.Ocular Microcurrent Therapy
Description & Mechanism: Microampere currents delivered directly to periocular tissues to stimulate cellular repair pathways.
Purpose: Aims to support RPE renewal and photoreceptor function.Optical Coherence Tomography (OCT) Biofeedback
Description & Mechanism: Real-time OCT imaging guides patients in subtle eye movements to optimize fixation on healthier retinal patches.
Purpose: Enhances visual performance during recovery.Vision Restoration Therapy (Computer-Based)
Description & Mechanism: Interactive software prompts saccadic training and peripheral awareness exercises.
Purpose: Strengthens alternative visual pathways when central vision is affected.
B. Exercise Therapies
Saccadic Eye-Movement Drills
Practice rapid, targeted eye movements to improve switching between fixation points.Accommodation Flexibility Training
Alternating focus between near and distant targets to maintain lens flexibility and reduce eye strain.Contrast Sensitivity Exercises
Viewing high-contrast patterns at varying distances to sharpen visual discrimination.Fixation Stability Workouts
Focusing on small targets to enhance steadiness and reduce micro-tremor.Dynamic Range Scanning
Tracking moving dots or objects across the visual field to maintain peripheral awareness.
C. Mind-Body Therapies
Mindfulness Meditation
Guided relaxation focusing on breath, which may lower systemic stress and indirectly support retinal healing.Progressive Muscle Relaxation
Sequentially tensing and relaxing facial and ocular muscles to reduce periorbital tension.Guided Imagery
Visualization exercises that promote ocular blood flow and calm neural pathways.
D. Educational Self-Management
Patient Education Sessions
Learning about ARPE’s natural course, symptom tracking, and the importance of follow-up examinations.Symptom Diary & Self-Monitoring
Recording vision changes (e.g., scotoma size, photopsias) to inform timely clinical reviews.
Drugs (Evidence-Based)
Though ARPE is self-resolving and typically requires no medication, case reports have explored anti-inflammatory agents to hasten recovery. Below are the most documented options:
Oral Prednisone (Systemic Corticosteroid)
Dosage: ~1 mg/kg/day for 1–2 weeks, then taper
Class: Glucocorticoid
Timing: Once daily in morning
Side Effects: Weight gain, hyperglycemia, mood swings, osteoporosis EyeWiki
Intravenous Methylprednisolone (Pulsed Steroid)
Dosage: 1 g/day for 3 days
Class: Corticosteroid
Timing: Single daily infusion
Side Effects: Fluid retention, hypertension, immunosuppression Lippincott Journals
Prednisolone Acetate 1% Eye Drops (Topical Steroid)
Dosage: 1 drop QID for 5–7 days
Class: Corticosteroid
Timing: Morning, midday, afternoon, evening
Side Effects: Elevated intraocular pressure, cataract risk BioMed Central
Oral Ibuprofen (NSAID)
Dosage: 400 mg every 6 hours as needed
Class: Non-steroidal anti-inflammatory
Timing: With meals to reduce GI upset
Side Effects: Gastric irritation, renal impairment PubMed
Ketorolac Tromethamine 0.5% Eye Drops (Topical NSAID)
Dosage: 1 drop QID for 1 week
Class: NSAID
Side Effects: Corneal toxicity with prolonged use
Naproxen (Oral NSAID)
Dosage: 250 mg BID
Class: NSAID
Side Effects: GI upset, headache
Acetazolamide (Carbonic Anhydrase Inhibitor)
Dosage: 250 mg TID
Class: Diuretic
Purpose: May reduce subretinal fluid
Side Effects: Paresthesias, electrolyte imbalance
Pentoxifylline (Microcirculation Enhancer)
Dosage: 400 mg TID
Class: Phosphodiesterase inhibitor
Side Effects: Dizziness, GI upset
Doxycycline (Tetracycline Antibiotic)
Dosage: 100 mg BID for 5–7 days
Class: Antibiotic/anti-inflammatory
Side Effects: Photosensitivity, GI upset
Low-Dose Aspirin (Antiplatelet)
Dosage: 81 mg daily
Class: Salicylate
Side Effects: Bleeding risk
Dietary Molecular Supplements
Although ARPE is not driven by nutritional deficiency, antioxidants and micronutrients that support retinal health are commonly recommended:
Vitamin C – 500 mg/day (Antioxidant) en.wikipedia.org
Vitamin E – 400 IU/day (Lipid antioxidant) en.wikipedia.org
Zinc – 80 mg/day (Cofactor for antioxidant enzymes) en.wikipedia.org
Copper – 2 mg/day (Balance zinc levels) en.wikipedia.org
Beta-Carotene – 15 mg/day (Precursor to vitamin A) en.wikipedia.org
Lutein – 10 mg/day (Macular pigment) en.wikipedia.org
Zeaxanthin – 2 mg/day (Macular pigment) en.wikipedia.org
Omega-3 Fatty Acids – 1,000 mg DHA/EPA daily (Anti-inflammatory)
Anthocyanins – 80 mg bilberry extract/day (Capillary strength)
Resveratrol – 100 mg/day (Anti-oxidative)
Advanced “Bisphosphonate, Regenerative, Viscosupplementation, Stem Cell” Drugs
While none are approved specifically for ARPE, the following emerging retinal therapies illustrate cutting-edge approaches with potential future applicability:
ABBV-RGX-314 (AAV8-Delivered Anti-VEGF Gene Therapy)
Administration: 1–2 suprachoroidal injections in wet AMD trials
Mechanism: AAV8 vector drives intraocular anti-VEGF antibody expression to reduce neovascular risk.
Status: Phase II AAVIATE trial showed stable BCVA with 80% fewer injections over 6 months Ophthalmology Advisor
Encapsulated Cell-Based CNTF Implant (NT-501 / Encelto)
Intravitreal Hyaluronic Acid (Healon-H)
Dosage: Single injection (typical: 1–2 mL of 1.4% solution)
Mechanism: Viscosupplementation to aid retinal reattachment and protect retinal layers during surgery.
Evidence: Used in complicated retinal detachment with long-term safety PubMed
Hyaluronic Acid Nanoparticles (HA-NS)
Dosage: Experimental intravitreal micro-doses of HA-coated nanoparticles
Mechanism: Targeted drug/gene delivery to RPE via CD44 receptor binding, enhancing penetration and controlled release.
Evidence: Improved outer retinal targeting in preclinical models PMC
Autologous CD34+ Stem Cell Intravitreal Injection
Dosage: Single injection of purified CD34+ bone marrow-derived cells (~10^5–10^6 cells)
Mechanism: Homing of progenitor cells to damaged retina, release of neurotrophic factors, promoting repair.
Evidence: Phase 1 RP trial showed safety and some visual improvements in 4/7 participants UC Davis Health
ESC-Derived RPE Cell Sheet (ASP7317)
Dosage: Subretinal sheet of ~200,000 RPE cells (Phase Ib)
Mechanism: Replaces damaged RPE, supporting photoreceptor function and preventing atrophy.
Status: Under investigation for geographic atrophy in dry AMD en.wikipedia.org
Surgeries (Procedures & Benefits)
Although ARPE seldom requires surgery, the following retinal procedures underpin management of more severe or misdiagnosed conditions:
Pars Plana Vitrectomy
Procedure: Removal of vitreous gel via three small incisions at the pars plana.
Benefits: Clears vitreous opacities, relieves traction on retina, and allows access for subretinal therapies.
Subretinal Cell or Gene Delivery
Procedure: Micro-incision and cannula placement under retina to inject therapeutic cells or vectors.
Benefits: Direct delivery to RPE/photoreceptors for regenerative or gene therapy.
Epiretinal Membrane Peeling
Procedure: Microsurgical removal of fibrous membranes on retinal surface.
Benefits: Restores retinal architecture, improves vision if epiretinal traction coexists.
Laser Photocoagulation
Procedure: Focal or grid application of laser burns to RPE.
Benefits: Stabilizes microaneurysms or focal leaks; not typically used in ARPE but in differential diagnoses.
Scleral Buckling
Procedure: External silicone band placed around eye equator to support retina.
Benefits: Treats rhegmatogenous retinal detachment; underscores importance of accurate diagnosis before ARPE misdiagnosis.
Preventions
Avoid Unnecessary Steroid Use (systemic or topical)
Protect Against Viral Illnesses (hand hygiene, vaccinations)
Manage Stress & Sleep to support immune balance
Use UV-Blocking Sunglasses outdoors
Maintain Balanced Diet rich in antioxidants
Control Blood Sugar & Blood Pressure
Schedule Regular Eye Exams after any sudden vision changes
Avoid Smoking (oxidative risk)
Limit Screen Time and take frequent breaks (20-20-20 rule)
Stay Hydrated to maintain ocular perfusion
When to See a Doctor
Persistent or enlarging central scotoma
Sudden drop in central visual acuity
New onset of metamorphopsia (distorted vision)
Photophobia or light intolerance
Any unexplained visual field defect
What to Do & What to Avoid
Do:
Keep symptom diary and rate vision daily
Attend scheduled OCT and visual acuity follow-ups
Rest eyes and avoid eye strain
Wear sunglasses in bright light
Follow your ophthalmologist’s instructions
Avoid:
6. Rubbing or pressing on your eyes
7. Sudden head-jerking movements
8. High-dose systemic steroids without indication
9. Excessive caffeine or alcohol (may affect microcirculation)
10. Self-prescribing eye drops or supplements
Frequently Asked Questions
What causes ARPE?
ARPE’s exact cause is unknown, but many patients report a recent mild viral infection. It’s thought to involve transient RPE inflammation.Is treatment always needed?
No—ARPE is self-limiting in nearly all cases and resolves without therapy. Treatment is reserved for severe or atypical presentations.How long does recovery take?
Most recover full vision within 4–8 weeks, although OCT changes may persist longer.Can ARPE recur?
Recurrences are exceedingly rare (<5% in small series).Will I have permanent vision loss?
In >90% of cases, vision returns to 20/20 with no lasting scotoma.Should I get antiviral medications?
No evidence supports antivirals; focus remains on observation and supportive care.Are imaging tests necessary?
Yes—OCT and fluorescein angiography confirm diagnosis and exclude other maculopathies.Can I drive during recovery?
If your vision drops below legal limits, avoid driving until it recovers.Is genetic testing helpful?
Genetic testing is not indicated for ARPE, as it is not inherited.Should I stop wearing contact lenses?
You may continue if comfortable, but switch to glasses if lenses irritate your eyes.Can pregnancy trigger ARPE?
No known link, though pregnancy-related immune changes affect other ocular diseases.Does ARPE affect both eyes?
It’s usually unilateral but can be bilateral in ~20% of cases.Should I take AREDS supplements?
They support overall retinal health but have not been studied in ARPE specifically.Can stress worsen symptoms?
High stress may exacerbate perception of vision changes; mind-body techniques can help.When is surgery considered?
Surgery is not used for ARPE itself but for complications misdiagnosed as other retinal detachments.
Disclaimer: Each person’s journey is unique, treatment plan, life style, food habit, hormonal condition, immune system, chronic disease condition, geological location, weather and previous medical history is also unique. So always seek the best advice from a qualified medical professional or health care provider before trying any treatments to ensure to find out the best plan for you. This guide is for general information and educational purposes only. Regular check-ups and awareness can help to manage and prevent complications associated with these diseases conditions. If you or someone are suffering from this disease condition bookmark this website or share with someone who might find it useful! Boost your knowledge and stay ahead in your health journey. We always try to ensure that the content is regularly updated to reflect the latest medical research and treatment options. Thank you for giving your valuable time to read the article.
The article is written by Team RxHarun and reviewed by the Rx Editorial Board Members
Last Updated: July 10, 2025.
