#8 Gonioscopy | GONIOSCOPY IN NARROW ANGLES

Introduction

This tutorial provides a step-by-step guide to performing gonioscopy in cases of narrow or closed angles. Understanding gonioscopy is crucial for diagnosing and managing conditions like primary angle-closure glaucoma (PACG) and related syndromes. This guide will clarify key concepts and techniques related to gonioscopy, ensuring effective evaluation of the anterior chamber angle.

Step 1: Understand the Key Terms

Before performing gonioscopy, it's important to familiarize yourself with the following terms:

• Occludable angles: Angles that can become closed, leading to increased intraocular pressure.
• Narrow angles: Angles that are narrower than normal, which may predispose patients to angle closure.
• PACS (Primary Angle Closure Suspect): Patients with narrow angles but without symptoms of angle closure.
• PAC (Primary Angle Closure): Patients who experience symptoms due to acute angle closure.
• PACG (Primary Angle Closure Glaucoma): A more severe condition where sustained angle closure leads to glaucoma.

Step 2: Gather Necessary Equipment

Before starting the gonioscopy procedure, ensure you have the following tools:

• Gonioscope: A specialized lens used to visualize the anterior chamber angle.
• Slit lamp: For illuminating and examining the eye.
• Topical anesthetic: To ensure patient comfort during the procedure.
• Appropriate light source: To enhance visibility of the angle structures.

Step 3: Prepare the Patient

Proper preparation is essential for a successful gonioscopy:

1. Explain the Procedure: Inform the patient about what to expect during the examination to alleviate any anxiety.
2. Administer Topical Anesthetic: Apply the anesthetic to the patient's eye to minimize discomfort.
3. Position the Patient: Ensure the patient is comfortably seated at the slit lamp.

Step 4: Perform Gonioscopy

Follow these steps to conduct the gonioscopy:

1. Use the Gonioscope: Place the gonioscope on the patient's eye, ensuring proper alignment.
2. Adjust the Slit Lamp: Set the slit lamp to provide a clear view of the anterior chamber angle.
3. Examine the Angle:
   • Look for structures such as the trabecular meshwork, scleral spur, and iris.
   • Assess the angle's width and note any signs of closure or obstruction.

Step 5: Document Findings

After examining the angle, it is crucial to document your findings accurately:

• Record the angle grade (using a grading system from 1 to 4).
• Note any abnormalities, such as peripheral anterior synechiae or pigmentation.
• Include any relevant details regarding the patient's symptoms and history.

Conclusion

Gonioscopy is a vital technique for evaluating narrow and closed angles, essential for managing potential glaucoma cases. By understanding the key terms, preparing appropriately, and following a systematic approach during the examination, practitioners can effectively assess the anterior chamber angle. Next steps may include further diagnostic tests or referrals based on the findings from gonioscopy.