Keratic Precipitates in Arlt’s Triangle

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Article Summary

Arlt’s triangle pigmented refers to a pattern of keratic precipitates (KPs)—clusters of inflammatory cells—deposited in a wedge-shaped, inverted triangular area on the central to inferior corneal endothelium. These precipitates are composed primarily of macrophages, epithelioid cells, and lymphocytes. In active granulomatous anterior uveitis, fresh KPs appear as white-yellow “mutton-fat” lesions; over time, as inflammation subsides or with steroid therapy, these larger granulomatous KPs acquire brown...

Key Takeaways

  • This article explains Types of Keratic Precipitates in Arlt’s Triangle in simple medical language.
  • This article explains Causes of Pigmented Arlt’s Triangle in simple medical language.
  • This article explains Symptoms Associated with Arlt’s Triangle Pigmented in simple medical language.
  • This article explains Diagnostic Tests in simple medical language.
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Definition

Arlt’s triangle pigmented refers to a pattern of keratic precipitates (KPs)—clusters of inflammatory cells—deposited in a wedge-shaped, inverted triangular area on the central to inferior corneal endothelium. These precipitates are composed primarily of macrophages, epithelioid cells, and lymphocytes. In active granulomatous anterior uveitis, fresh KPs appear as white-yellow “mutton-fat” lesions; over time, as subsides or with therapy, these larger granulomatous KPs acquire brown pigment granules, shrink, and sometimes leave faint halos when they detach, giving rise to the pigmented variant of Arlt’s triangle EyeWikiEnto Key. The shape results from gravity-driven sedimentation and convection currents within the anterior chamber, directing cells toward the cooler, lower corneal endothelium EyeWiki. The presence of pigment indicates a or resolving process and can mark previous inflammatory episodes, aiding clinicians in assessing disease chronicity and treatment response.

Types of Keratic Precipitates in Arlt’s Triangle

Although Arlt’s triangle describes distribution rather than KP subtype, various KP morphologies can occupy this triangular zone:

  1. Fresh Nongranulomatous KPs
    These are small, round, bright-white precipitates seen in early uveitis. They indicate active inflammation with predominance of polymorphonuclear leukocytes Review of Optometry.

  2. Mutton-Fat (Granulomatous) KPs
    Large, greasy-yellowish clusters of macrophages and epithelioid cells form the classic Arlt’s triangle in granulomatous uveitis. Their size (up to 1 mm) and greasy appearance distinguish them from finer white KPs Vagelos College.

  3. Pigmented KPs
    Represent older, degenerating granulomatous KPs that have taken up melanin pigment from melanocytes or degenerating cells. These brownish-black spots shrink over time and signal a resolving or past inflammatory event Ento Key.

  4. Ghost (Descemet’s-Covered) KPs
    Long-standing precipitates may be overlaid by new Descemet’s membrane, appearing pale or glassy (“ghost” KPs). They reflect prior inflammation and endothelial remodeling Ento Key.

  5. Red KPs
    Rare in hemorrhagic uveitis, these precipitates contain red blood cells and may deposit in Arlt’s triangle during inflammation or Wikipedia.

Causes of Pigmented Arlt’s Triangle

  1. Sarcoidosis
    A multisystem granulomatous disease often affecting the eye. Noncaseating granulomas trigger chronic anterior uveitis with mutton-fat KPs that pigment over time EyeWiki.

  2. Syphilis
    Treponema pallidum can cause granulomatous keratic precipitates in Arlt’s triangle. Pigmented KPs may persist after therapy EyeWiki.


  3. Ocular provokes granulomatous inflammation and mutton-fat KPs. Healing lesions often leave pigmented spots in the triangle EyeWiki.

  4. Vogt-Koyanagi-Harada (VKH) Disease
    An against melanocytes causes granulomatous uveitis. Pigmented KPs can mark past flares, and iris changes accompany them EyeWiki.

  5. Sympathetic Ophthalmia
    granulomatous uveitis following ocular injury. Mutton-fat KPs deposit in Arlt’s triangle; chronic cases develop pigmented residuals EyeWiki.

  6. Lens-Induced Uveitis (Phacoantigenic)
    Exposure of lens proteins after trauma or surgery triggers granulomatous KPs. Pigmentation follows resolution under steroids EyeWiki.

  7. Brucellosis
    Brucella infection can involve the eye, producing a granulomatous anterior uveitis with pigmented KPs in the inferior EyeWiki.

  8. Leprosy
    Mycobacterium leprae may lead to chronic anterior uveitis. The slow course fosters pigmented KP formation in Arlt’s triangle EyeWiki.

  9. Toxocariasis
    Ocular larva migrans can cause granulomatous inflammation and pigmented KPs as lesions heal EyeWiki.

  10. Coccidioidomycosis
    Valley fungus occasionally involves the eye, with granulomatous KPs depositing in the triangle and pigmenting on resolution EyeWiki.

  11. Lyme Disease
    Borrelia burgdorferi can provoke chronic anterior uveitis; healing stages often show pigmented Arlt’s triangle lesions EyeWiki.

  12. Herpes Simplex Virus (HSV)
    HSV anterior uveitis produces granulomatous KP clusters in Arlt’s triangle. Over time, these pigmented deposits can persist, marking prior flares PubMed.

  13. Varicella-Zoster Virus (VZV)
    VZV uveitis yields medium-sized granulomatous KPs in the triangle; chronic cases develop pigmented remnants PubMed.

  14. Cytomegalovirus (CMV)
    CMV anterior uveitis features coin-like or pigmented endothelial lesions often within Arlt’s triangle, especially in older patients PubMed.

  15. Rubella Virus
    Fuchs heterochromic iridocyclitis (often rubella-linked) shows diffuse stellate KPs, but occasional wedge-shaped pigmented precipitates can localize in the inferior cornea AAO.

Symptoms Associated with Arlt’s Triangle Pigmented

  1. Eye
    A dull ache or sharp pain around the eye results from ciliary muscle and iris inflammation Review of Optometry.


  2. arises due to irritation of inflamed iris and ciliary body tissues Review of Optometry.

  3. Redness (Ciliary Flush)
    Hyperemia around the limbus from inflamed perilimbal vessels gives the classic “red eye” Review of Optometry.


  4. Corneal or media opacity from KPs and anterior chamber reduces image clarity Review of Optometry.

  5. Tearing (Epiphora)
    Reflex lacrimation occurs as the inflamed eye attempts to soothe irritation Review of Optometry.

  6. Floaters
    Inflammation spill-over into the vitreous can produce moving spots in the visual field Review of Optometry.

  7. Halos Around Lights
    Corneal edema from endothelial dysfunction causes diffraction of light, producing colored rings Review of Optometry.

  8. Mucous Discharge
    Chronic inflammation may lead to sticky, mucous discharge coating the lashes canadianjournalofophthalmology.ca.


  9. Periocular pain often extends as a headache due to shared innervation pathways Review of Optometry.

  10. Irregularity
    Posterior synechiae (iris-lens adhesions) from inflammation can distort pupil shape and responsiveness canadianjournalofophthalmology.ca.

Diagnostic Tests

Physical Examination

  1. Slit-Lamp Biomicroscopy
    Uses a focused beam of light and microscope to visualize KPs, flare, and Arlt’s triangle directly EyeWiki.

  2. Testing
    Measures clarity of vision to gauge functional impact of anterior chamber inflammation Review of Optometry.

  3. Tonometry
    Checks intraocular pressure, as uveitis can cause both spikes (from trabeculitis) and drops (from ciliary shutdown) Review of Optometry.

  4. Pupil Examination
    Assesses for irregular shape or poor dilation due to synechiae, indicating chronic inflammation canadianjournalofophthalmology.ca.

Manual Tests

  1. Gonioscopy
    A mirrored lens manually placed on the eye to inspect the anterior chamber angle for peripheral anterior synechiae or neovascularization Lippincott Journals.

  2. Van Herrick’s Test
    Estimates peripheral anterior chamber depth by comparing corneal thickness to anterior chamber space, assessing angle closure risk Lippincott Journals.

  3. Seidel’s Test
    Applies fluorescein dye and cobalt blue light to detect any aqueous leak from corneal perforations or postoperative wounds Lippincott Journals.

  4. Iris Transillumination
    Shines a bright light through the iris to reveal defects or , aiding in diagnosing pigment dispersion and viral iridocyclitis OphthoGenie.

Laboratory & Pathological Tests

  1. Complete Blood Count (CBC)
    Evaluates systemic inflammation, anemia, or infection markers that may underlie granulomatous uveitis educate.choroida.com.

  2. Angiotensin-Converting Enzyme (ACE) Level
    Elevated in sarcoidosis; supports diagnosis when correlated with ocular findings educate.choroida.com.

  3. Syphilis Serology (VDRL/RPR & FTA-ABS)
    Detects Treponema pallidum infection; essential in granulomatous anterior uveitis work-up educate.choroida.com.

  4. Polymerase Chain Reaction (PCR) of Aqueous Humor
    Identifies viral DNA (HSV, VZV, CMV, rubella) to confirm viral anterior uveitis PubMed.

Electrodiagnostic Tests

  1. Electroretinogram (ERG)
    Measures retinal function; may show indirect effects of chronic inflammation Wikipedia.

  2. Visual Evoked Potential (VEP)
    Assesses optic nerve and visual pathway integrity, useful if inflammation extends posteriorly Wikipedia.

  3. Electrooculogram (EOG)
    Tests the retinal pigment epithelium function; can detect subtle chronic changes from uveitis Wikipedia.

  4. Multifocal ERG
    Maps localized retinal function; helps evaluate macular involvement in chronic cases Wikipedia.

Imaging Tests

  1. Anterior Segment Optical Coherence Tomography (AS-OCT)
    Provides cross-sectional images of the cornea and anterior chamber to visualize precipitates and membranes Lippincott Journals.

  2. Ultrasound Biomicroscopy (UBM)
    High-frequency ultrasound imaging of the anterior segment, detailing angle structures and ciliary body changes Lippincott Journals.

  3. B-Scan Ocular Ultrasound
    Assesses vitreous and posterior segment for spillover inflammation when media are opaque canadianjournalofophthalmology.ca.

  4. Fundus Fluorescein Angiography (FFA)
    Visualizes retinal vasculature leakage or ischemia in chronic uveitis, indicating posterior involvement Lippincott Journals.

Disclaimer: Each person’s journey is unique, treatment planlife stylefood habithormonal conditionimmune systemchronic 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 13, 2025.

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Doctor visit helper

Prepare before seeing a doctor

A simple rural-patient checklist to help you explain symptoms clearly, ask better questions, and avoid unsafe self-treatment.

Safety note: This is not a prescription or diagnosis. For severe symptoms, pregnancy danger signs, children with serious illness, chest pain, breathing difficulty, stroke-like weakness, or major injury, seek urgent care.

Which doctor may help?

Start with a registered doctor or the nearest qualified health center.

What to tell the doctor

  • Write when the problem started and how it changed.
  • Bring old prescriptions, investigation reports, and current medicines.
  • Write allergies, pregnancy status, diabetes, kidney/liver disease, and major past illnesses.
  • Bring one family member if the patient is weak, elderly, confused, or a child.

Questions to ask

  • What is the most likely cause of my symptoms?
  • Which danger signs mean I should go to hospital quickly?
  • Which tests are necessary now, and which can wait?
  • How should I take medicines safely and what side effects should I watch for?
  • When should I come for follow-up?

Tests to discuss

  • Vital signs: temperature, pulse, blood pressure, oxygen saturation
  • Basic physical examination by a clinician
  • CBC, urine test, blood sugar, or imaging only when clinically needed

Avoid these mistakes

  • Do not use antibiotics, steroid tablets/injections, or strong painkillers without proper medical advice.
  • Do not hide pregnancy, kidney disease, ulcer, allergy, or blood thinner use.
  • Do not delay emergency care when danger signs are present.

Medicine safety and first-aid guide

This section is for patient education only. It does not replace a doctor, pharmacist, or emergency care.

Safe first steps

  • Avoid heavy lifting, sudden bending, and prolonged bed rest.
  • Use comfortable posture and gentle movement as tolerated.
  • Discuss physiotherapy, X-ray, or MRI only when clinically needed.

OTC medicine safety

  • For mild back pain, pain-relief medicine may be discussed with a doctor or pharmacist.
  • Avoid repeated painkiller use if you have kidney disease, stomach ulcer, uncontrolled blood pressure, or are taking blood thinners.

Avoid these mistakes

  • Do not start antibiotics without a proper medical decision.
  • Do not use steroid tablets or injections casually for quick relief.
  • Do not delay emergency care because of home remedies.

Get urgent help if

  • Back pain with leg weakness, numbness around private area, loss of urine/stool control, fever, cancer history, or major injury needs urgent care.
Medicine names, dose, and timing must be decided by a qualified clinician or pharmacist after checking age, pregnancy, allergy, other diseases, and current medicines.

For rural patients and family caregivers

Patient health record and symptom diary

Write your symptoms, medicines already taken, test results, and questions before visiting a doctor. This note stays on your device unless you print or copy it.

Doctor to discuss: Medicine doctor / pediatrician for children / qualified clinician
Tests to discuss with doctor
  • Temperature chart and hydration assessment
  • CBC with platelet count if fever persists or dengue/other infection is possible
  • Urine test, malaria/dengue tests, chest evaluation, or blood culture only when clinically indicated
Questions to ask
  • What is the most likely cause of my symptoms?
  • Which warning signs mean I should go to emergency care?
  • Which tests are really needed now?
  • Which medicines are safe for my age, pregnancy status, allergy, kidney/liver/stomach condition, and current medicines?
  • Do I need antibiotics, or is this more likely viral?

Emergency warning signs such as chest pain, severe breathing difficulty, sudden weakness, confusion, severe dehydration, major injury, or loss of bladder/bowel control need urgent medical care. Do not wait for online information.

Safe pathway to proper treatment

Care roadmap for: Keratic Precipitates in Arlt’s Triangle

Use this simple roadmap to understand the next safe steps. It is educational and does not replace examination by a doctor.

Go to emergency care if you notice:
  • Severe or rapidly worsening symptoms
  • Breathing difficulty, chest pain, fainting, confusion, severe weakness, major injury, or severe dehydration
Doctor / service to discuss: Qualified healthcare provider; specialist depends on symptoms and examination.
  1. Step 1

    Check danger signs first

    If danger signs are present, seek emergency care and do not wait for online information.

  2. Step 2

    Record the symptom story

    Write when symptoms started, severity, medicines already taken, allergies, pregnancy status, and test results.

  3. Step 3

    Visit a qualified clinician

    A doctor, nurse, or qualified healthcare provider can examine you and decide which tests or treatment are needed.

  4. Step 4

    Do only useful tests

    Do tests after clinical assessment. Avoid unnecessary tests, random antibiotics, or repeated medicines without diagnosis.

  5. Step 5

    Follow up and return early if worse

    If symptoms worsen, new warning signs appear, or treatment is not helping, return for review quickly.

Rural patient practical tips
  • Take a written symptom diary and all previous prescriptions/test reports.
  • Do not hide medicines already taken, even herbal or over-the-counter medicines.
  • Ask which warning signs mean urgent referral to hospital.

This roadmap is for education. A real diagnosis and treatment plan requires history, examination, and clinical judgment.