⚡ Key Takeaways
- Corneal suturing is a fundamental ophthalmic skill every resident must master
- Use 10-0 Nylon for most corneal sutures — it's thin, strong, and well-tolerated
- The key is equal depth on both sides and proper tension
- Always enter perpendicular to the corneal surface, then follow the needle's curve
- Practice the 1-1-1 rule: 1mm from the wound edge, 1mm deep, 1mm apart
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Why Learn Corneal Suturing?
Whether you're closing a cataract wound that's leaking, repairing a corneal laceration, or performing a keratoplasty, corneal suturing is a skill you'll use throughout your career. This 10-step guide breaks the technique down into manageable steps.
The 10 Steps
Step 1: Load the Needle
Grasp the needle with your needle holder at approximately two-thirds from the tip. The needle should be secure but not crushed. The curve of the needle should point in your intended direction of travel.
Step 2: Stabilize the Globe
Use a tying forceps or 0.12mm forceps to stabilize the eye. Grip the cornea gently near the wound edge — just enough to prevent the globe from rotating when you enter with the needle.
Step 3: Enter Perpendicular
The needle should enter the corneal surface perpendicular (at 90°). This ensures you reach the appropriate depth. Too shallow and the suture will cheese-wire through; too deep and you risk perforating into the anterior chamber.
Step 4: Follow the Curve
Once the needle penetrates the surface, rotate your wrist to follow the needle's natural curve through the corneal stroma. Don't push — rotate.
Step 5: Exit at Equal Depth
The needle should emerge on the other side of the wound at the same depth as the entry point. Unequal depth causes wound gaping and astigmatism.
Step 6: Pull the Suture Through
Grasp the needle tip with the forceps and pull it through. Leave a short tail on the entry side for tying.
Step 7: Tie the First Throw
Wrap the suture around the needle holder and grasp the short tail. The first throw should be a double wrap (surgeon's knot) to prevent slippage.
Step 8: Set the Tension
Pull the knot down gently. The wound edges should be just apposed — not overtightened (which causes compression and astigmatism) and not too loose (which causes gaping).
Step 9: Complete the Knot
Add two more single throws, alternating direction. The final knot should be square (alternating over-under) and sit snugly against the corneal surface.
Step 10: Bury the Knot
Rotate the knot so it's buried in the stroma, not sitting on the surface where it can cause irritation and attract deposits. Trim the tails short.
Frequently Asked Questions
What suture material is used for corneal sutures?
10-0 Nylon is the most common choice. It's monofilament, strong for its size, and causes minimal tissue reaction. For some applications (temporary closure), 10-0 Vicryl (absorbable) may be used.
How deep should the suture pass?
Aim for approximately 90% corneal depth. Too shallow and it cheese-wires through; too deep and you perforate into the anterior chamber. With practice, you develop a feel for the right depth.
When should sutures be removed?
Timing varies: post-cataract sutures typically come out at 4-8 weeks, while keratoplasty sutures may stay for months to years. Suture removal is guided by wound healing, stability, and astigmatism management.
Want to practice suture removal too?
Check out the corneal suture removal guide or subscribe to the YouTube channel for more clinical skills.