What are hypopyon and lipid flare?

Hypopyon refers to an accumulation of white blood cells (pus) in the anterior chamber of the eye, while lipid flare describes the presence of lipids causing cloudiness or a shimmering appearance in that space. Both are commonly associated with redness, discharge, or vision changes, and require further veterinary assessment including physical examination and imaging.

What should I do if I notice my pet has a red or swollen eye?

Start by documenting the symptoms at home with photos or videos. Do not apply any eye drops without veterinary guidance, and prevent your pet from rubbing the eye. If the eye is producing discharge, appears painful, or if systemic signs develop, take your pet to a vet promptly.

What tests will the vet run to identify the cause?

Common tests include a physical ophthalmic examination, complete blood count, and biochemistry panel. When needed, ocular ultrasound, CT, or MRI may be arranged to evaluate the anterior chamber and surrounding structures.

What information can I prepare before the appointment?

Bring the onset date of symptoms, daily food, water, and toilet records, recent weight measurements, a list of current medications and supplements, and any photos or videos of the symptoms. This helps the vet assess your pet's condition more quickly.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Hypopyon & Lipid Flare in Dogs and Cats: Symptoms, Eye Exam & Home Care [2025]

Hypopyon and lipid flare are accumulations of white blood cells or lipids in the anterior chamber of the eye, usually caused by intraocular inflammation (uveitis). Identifying the underlying cause and treating with anti-inflammatory medication is essential.

Take 1 minute to check the symptoms first

Last updated: 2026/01/17

Pethealthmap Editorial Team

Sources: ISFM, AAHA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek Emergency Care Immediately

•Heavy discharge of pus from the eye or continuous bleeding that does not stop
•Severe eye swelling causing the eye to remain closed and unable to open
•Lethargy with clear refusal to eat or drink

Schedule a Clinic Visit Soon (within 24–72 hours)

•Persistent redness or discharge in one eye lasting several days without improvement
•Repeated blinking or obvious light sensitivity with reluctance to open the eye
•Suspected vision loss or increased frequency of bumping into furniture

01What symptoms indicate something is wrong?

Hypopyon and lipid flare are often caused by eye infection or inflammation. Your pet may show local eye changes as well as general health changes — early evaluation is recommended.

Noticeable swelling or puffiness around or near the eye
Red or swollen eye, increased discharge, or pus-like secretions
Lethargy, reduced activity, or increased sleepiness
Decreased appetite or noticeable changes in eating behaviour
Changes in urination or defecation, or systemic signs such as vomiting or diarrhoea
Significant changes in body weight or water intake over a short period
Pet shows discomfort or avoidance when the area around the eye is touched

02How can you assess the situation at home? Key observations and when to seek emergency care

Home observation and record-keeping provides your vet with valuable information. Record symptoms systematically, including timing and any changes.

Record changes in energy level and interactions with people each day
Weigh your pet at the same time each day and note any weight changes
Measure and record daily water intake and drinking frequency
Record appetite, amount eaten, and any refusal to eat
Record the frequency, colour, and any unusual odour of bowel movements or urine
Take and save photos or videos of the eye symptoms using your phone
Bring all observation records to the specialist consultation for the vet's reference

03How will the vet make a diagnosis? Common diagnostic tests

At the clinic, the vet will perform a thorough physical examination alongside laboratory and imaging tests to identify the cause and determine the appropriate treatment.

Comprehensive physical examination, including ophthalmic and neurological assessment

Complete blood count (CBC) to assess infection and inflammation markers

Biochemistry panel to evaluate liver and kidney function and metabolic status

Urinalysis to help rule out systemic conditions or complications

Specialist eye examination (slit-lamp biomicroscopy, intraocular pressure measurement) to assess the anterior chamber

Advanced imaging (ocular ultrasound, CT or MRI) to evaluate structural detail

It is recommended to book a clinic with advanced imaging equipment and an ophthalmology specialist

04What comes after diagnosis? Medication, dietary changes & care guide

Treatment and follow-up depend on the underlying cause and severity. Regular check-ups and home care are essential for recovery and minimising complications.

The vet may recommend medication or other treatments based on the examination findings
Schedule regular follow-up visits and any required imaging or laboratory tests as directed
Temporarily adjust diet as needed and continue to monitor weight changes
Provide a quiet, clean resting environment at home and minimise stimulation
Record and report any medication side effects or worsening symptoms to the vet
If further intervention is needed, the vet will arrange a referral to a specialist or hospital

05What should you prepare before the vet visit? Key information to help your vet diagnose quickly

Prepare a detailed record of when symptoms started and how they have progressed

List specific records of daily food intake, water consumption, and urination or defecation

Bring recent weight records or home measurements

Prepare a list of all current and past medications and supplements

Bring photos or videos of the symptoms to help the vet observe the progression

Book your appointment in advance and let the clinic know that advanced imaging may be required

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.

Related Symptoms (You May Also Be Looking For)

Eyelid spasm

Cloudy cornea

Tissue swelling

Excessive tearing

Constricted pupils

Vision loss