Name of the Procedure:

Electroretinography (ERG) with interpretation and report, pattern (PERG)
Common name: PERG
Technical term: Pattern Electroretinography

Summary

Pattern Electroretinography (PERG) is a diagnostic test that measures the electrical responses of the retina, specifically focusing on the ganglion cells, to visual stimuli. It provides detailed information about the functionality of the retina and the optic nerve.

Purpose

Medical Condition or Problem: PERG addresses various retinal and optic nerve disorders.
Goals or Expected Outcomes: The test helps diagnose diseases affecting the inner retina, such as glaucoma and optic neuropathies. It aims to detect abnormalities in the electrical activity of the retina, guiding effective treatment plans.

Indications

Symptoms/Conditions:

• Reduced vision or unexplained vision loss
• Visual field defects
• Suspected or confirmed glaucoma
• Retinal diseases like macular degeneration or retinitis pigmentosa

Patient Criteria:

• Individuals with unexplained changes in vision
• Patients at risk of or with early-stage glaucoma
• Those requiring assessment of retinal function for various ocular conditions

Preparation

Pre-procedure Instructions:

• No specific fasting required.
• Patients should inform their doctor about any medications they are taking.
• Dilating eye drops may be administered to facilitate the test.

Diagnostic Tests or Assessments Required:

• A comprehensive eye examination prior to the procedure.

Procedure Description

1. Preparation: The patient is seated comfortably, and dilating eye drops may be used.
2. Electrode Placement: Small electrodes are placed on the patient's head and near the eyes.
3. Stimulus Presentation: The patient is asked to focus on a screen displaying alternating patterns (e.g., checkerboards or gratings).
4. Recording: The electrical activity of the retina in response to the visual stimuli is recorded by the electrodes.
5. Data Analysis: The recorded signals are analyzed to assess retinal function.

Tools and Equipment:

• Visual stimulus generator (display screen)
• Electrodes and amplifiers
• Diagnostic computer system

Anesthesia or Sedation:

• Typically, no anesthesia or sedation is required.

Duration

The procedure usually takes about 30 to 60 minutes.

Setting

The procedure is performed in an eye clinic, outpatient clinic, or hospital setting specialized in ophthalmic diagnostics.

Personnel

• Ophthalmologist or optometrist trained in PERG
• Technicians specialized in electrophysiological testing

Risks and Complications

Common Risks:

• Mild discomfort or irritation from the electrodes.

Rare Risks:

• Infection or allergic reaction to the dilating drops or electrode gel.

Possible Complications and Management:

• Rare but manageable on-site or with appropriate medical care.

Benefits

Expected Benefits:

• Accurate diagnosis of retinal and optic nerve disorders.
• Early detection of glaucoma and other conditions, leading to better management and outcomes.

Realization Time:

• Immediate results analysis, though a formal report may take a few days.

Recovery

Post-procedure Care and Instructions:

• Patients can resume normal activities immediately.
• If dilating drops were used, light sensitivity may persist for a few hours; wearing sunglasses is advised.

Recovery Time:

• No significant recovery time is necessary.

Follow-up Appointments:

• Usually scheduled as needed based on the results.

Alternatives

Other Treatment Options:

• Optical coherence tomography (OCT), Visual Evoked Potential (VEP), and Fundus Photography.

Pros and Cons:

• OCT provides structural images but not functional assessment.
• VEP assesses optic nerve function but not as specific to retinal ganglion cells.
• Fundus photography offers anatomical details but lacks functional diagnostics.

Patient Experience

During the Procedure:

• Patients may feel minor discomfort from the electrodes and drops.
• They are required to stay focused on visual stimuli.

After the Procedure:

• Some temporary light sensitivity if dilating drops were used.
• Generally, no pain or significant discomfort.

Pain Management and Comfort Measures:

• No significant pain involved; comfort measures include dimming lights post-procedure if dilating drops were used.