Round needle
Use: When you want to minimize injury in soft tissue.
Typical use: Conjunctival suturing in glaucoma filtering surgery, vascular suturing.
Comprehensive Guide to Ophthalmic Sutures
Key points at a glance
Section titled “Key points at a glance”1. What are ophthalmic sutures?
Section titled “1. What are ophthalmic sutures?”In ophthalmic surgery, choosing the right suture is one of the keys to a successful operation. A suture is a method that realigns tissue in the correct position and keeps it stable so it does not shift until wound healing is complete; its role is to hold the wound and promote healing.
In recent years, surgery has become increasingly sutureless and less invasive, so there are fewer situations where sutures are needed. Sutureless strong corneal wounds, tissue adhesives, and intraocular tamponade are techniques that achieve the purpose of suturing by other means. However, in complex trauma and certain intraocular surgeries, the choice of suture and the suturing technique can affect the postoperative outcome.
Most suturing needles used in ophthalmic surgery are eyeless needles (the suture and needle are integrated). Eyed needles are rarely used because threading them causes more tissue injury.
The standard for suture thickness follows the USP (United States Pharmacopeia). The larger the number, the finer the suture (0-0 is the thickest, 11-0 the thinnest), and suture lengths are generally about 15 to 45 inches.
Q
How are absorbable and non-absorbable sutures used differently?
A
Absorbable sutures (typified by Vicryl®) lose tensile strength within a few weeks and are absorbed by the body in about two months. They are used for sutures intended to provide temporary wound support, such as in strabismus surgery and vitreous surgery. Non-absorbable sutures (nylon and polypropylene) are used for corneal transplantation, scleral suturing, and intraocular lens fixation procedures, where long-term tension retention is needed.
2. Suture classification and selection criteria
Section titled “2. Suture classification and selection criteria”
Yang Sun et al. Application of sutureless corneal incision for patients with congenital ectopia lentis - Is it feasible, effective and safe?. International Journal of Medical Sciences. 2024 May 30; 21(8):1541. Figure 1. PMCID: PMC11186419. License: CC BY.
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Types of suturing needles
Section titled “Types of suturing needles”The cross-sectional shape of the suturing needle is chosen according to the tissue characteristics and the purpose of the wound.
Cutting needle
Use: Has a triangular cutting tip and penetrates firm tissue.
Typical use: Eyelid skin suturing.
Spatula needle
Use: A flat tip with a horizontal cutting edge. Causes less tissue damage than a cutting needle.
Typical use: Scleral suture passage in scleral buckling surgery and strabismus surgery.
Inverted trapezoid needle
Use: The cross-section is an inverted trapezoid. Suitable for passing a suture through the corneoscleral area.
Typical uses: Corneoscleral suturing, corneal suturing.
Suture materials and characteristics
Section titled “Suture materials and characteristics”Sutures are selected based on the combination of material and absorbability. The table below shows the main characteristics and uses of major sutures.
| Material | Absorbability | Main uses |
|---|---|---|
| Nylon | Non-absorbable | Corneal transplant, cataract, glaucoma, vitrectomy, eyelid |
| Vicryl® | Absorbable (about 2 months) | Vitrectomy wound, extraocular muscle suturing |
| Silk | Non-absorbable | Conjunctival suture / traction suture |
| Virgin silk | Non-absorbable | Conjunctival suture (less tissue reaction than silk) |
| Prolene® | Non-absorbable | Intraocular lens fixation / iris suturing |
| Polyester | Non-absorbable | Buckle material fixation |
Details of each material are shown below.
- Nylon: A synthetic monofilament nonabsorbable suture. It causes very little tissue reaction and can remain in tissue for a long time, such as in corneal transplantation. Used for scleral sutures in cataract surgery, corneal sutures in corneal transplantation, conjunctival sutures in glaucoma surgery, scleral wound sutures in vitreoretinal surgery, and eyelid skin sutures.
- Polyglactin 910 (Vicryl®): A synthetic braided absorbable suture. For 8-0, its tensile strength decreases to 75% after 2 weeks, 40% after 3 weeks, and 25% after 4 weeks, and it is absorbed by hydrolysis in about 8 weeks (about 2 months). It causes less tissue reaction than silk but more than nylon. Used for scleral wound sutures in vitreoretinal surgery and extraocular muscle sutures in strabismus surgery.
- Silk: A natural fiber nonabsorbable suture. It causes a tissue reaction to foreign protein. Used for conjunctival sutures and traction sutures.
- Virgin silk: A twisted nonabsorbable suture. It causes less tissue reaction than silk. Used for conjunctival sutures.
- Polypropylene (Prolene®): A synthetic monofilament nonabsorbable suture. It has strong, stable tensile strength. It causes very little tissue reaction. Care is needed because tight suturing can easily induce astigmatism. Used for intraocular lens fixation and iris sutures.
- Polyester (Dacron®): A synthetic braided nonabsorbable suture. It remains stable in the body and maintains tensile strength for a long time. Used for buckle fixation.
Factors to Consider When Choosing
Section titled “Factors to Consider When Choosing”The following factors are considered when choosing a suture.
- The strength of external force applied to the wound
- Whether the goal is to promote scarring or minimize tissue reaction
- How long the suture needs to keep the wound closed
- The more delicate the tissue, the lower the wound tension, and the more important it is to minimize scarring, the finer the suture should be.
Q
Is there any problem with using nylon suture for conjunctival sutures?
A
Nylon is not recommended for conjunctival sutures because it is more likely to cause a foreign-body sensation after surgery. For conjunctival sutures, it is common to use an absorbable suture such as Vicryl® (8-0, for example) or virgin silk.
3. Use of sutures by type of eye surgery
Section titled “3. Use of sutures by type of eye surgery”This section shows how sutures are selected and used for each type of surgery. The table below summarizes typical combinations.
| Surgery | Suture used | Approximate size |
|---|---|---|
| Cataract surgery (wound closure) | Nylon | 10-0 |
| Vitrectomy (wound closure) | Vicryl® | 8-0 |
| Glaucoma (scleral flap) | Nylon | 10-0 |
| Scleral buckling (buckle fixation) | Polyester | 5-0 |
| Intraocular lens fixation | Prolene® | 9-0 or 8-0 |
| Corneal suturing and corneal transplantation | Nylon | 10-0 |
| Strabismus surgery (extraocular muscles) | Vicryl® | 6-0 |
Cataract surgery
Section titled “Cataract surgery”In principle, the wound closes on its own without sutures. If early perforation or aqueous leakage is seen, suture with 10-0 nylon. In children, the tissue is soft and less likely to close on its own, so sutures are often needed.
Vitreous surgery
Section titled “Vitreous surgery”If leakage from the wound is seen, such as after peripheral vitreous dissection, suture with 8-0 Vicryl® (a 2-1 knot is sufficient). No sutures are needed for ultra-small incisions such as 25G or 27G.
Glaucoma surgery
Section titled “Glaucoma surgery”The scleral flap is sutured through the full thickness with 10-0 nylon (spatulated needle). Because the amount of aqueous leakage is controlled by the tightness of the sutures, this directly affects postoperative eye pressure management and is an important technique. The conjunctiva is sutured with 10-0 nylon (round needle). For aqueous leakage from the limbus, use a compression suture (10-0 nylon, spatulated needle).
Scleral buckling surgery (scleral indentation surgery)
Section titled “Scleral buckling surgery (scleral indentation surgery)”After securing the rectus muscle with 4-0 silk, pass 5-0 polyester through the outer two-thirds of the sclera.
Intraocular lens suture fixation
Section titled “Intraocular lens suture fixation”Polypropylene (Prolene®) is used to suture the intraocular lens to the sclera. Use 9-0 or 8-0 Prolene® suture. Dislocation of the intraocular lens due to degradation of 10-0 polypropylene suture has been reported, and because 9-0 polypropylene suture is about twice as strong as 10-0 polypropylene suture, 9-0 is recommended.
Q
Why is 9-0 polypropylene suture recommended for intraocular lens fixation?
A
Dislocation of the intraocular lens due to degradation of 10-0 polypropylene suture has been reported, and the reason for recommending 9-0 polypropylene suture is that it is about twice as strong as 10-0 polypropylene suture. Because long-term fixation within the sclera is needed, suture strength stability is important.
Corneal suturing and corneal transplantation
Section titled “Corneal suturing and corneal transplantation”Use 10-0 nylon. If the suture is tied too tightly, corneal astigmatism and irregular astigmatism can easily occur, so care is needed. Take a longer bite and suture with just enough tension that the corneal margin does not rise. In penetrating keratoplasty, suture removal takes 6 months to 1 year. Suture loosening or breakage can trigger corneal epithelial damage, infection, and rejection, and more than half of late infections are said to be caused by sutures.
Sclerocorneal laceration
Section titled “Sclerocorneal laceration”As a rule, suturing near the limbus is done first with 8-0 or 9-0 nylon, then additional sutures are placed toward the posterior side. For scleral lacerations, one method is to secure strength with 6-0 polyester and suture the gaps with 8-0 Vicryl®. Some surgeons prefer nylon for scleral suturing, while others prefer Vicryl®; suture sizes used range from 6-0 to 8-0.
Strabismus surgery
Section titled “Strabismus surgery”The extraocular muscle is sutured to the sclera with 6-0 Vicryl®.
Guide to knot throws
Section titled “Guide to knot throws”For 10-0 nylon, 3-1-1, and for 8-0 Vicryl®, 2-1-1 or 2-1 is enough to achieve adequate knot security.
4. Suturing mechanics and suture removal
Section titled “4. Suturing mechanics and suture removal”Principles of suturing
Section titled “Principles of suturing”The basic principle for suture depth and length is “deep & short.” By taking the suture deeply and with a short bite width within the tissue, secure wound grasp and accurate realignment can be achieved.
- Interrupted sutures: The suture tends to form a circle. A perfectly round needle path is ideal; insert the needle perpendicular to the wound and pass it with a smooth rotational motion.
- Continuous sutures: The suture tends to become a straight line. A V-shaped series of needle passes is ideal; make sure each stitch is placed at equal intervals.
How to use the needle holder
Section titled “How to use the needle holder”Grasp the needle with the needle holder about one-third of the way back from the tip (about two-thirds of the way from the needle tip). Do not touch the needle tip (because cutting ability decreases). Avoid holding the swage end, as this can deform the needle.
Causes of suture loosening
Section titled “Causes of suture loosening”There are three main causes of suture loosening.
- Loose suturing: The sutures are originally loose, or the balance with adjacent sutures is poor.
- Cheese-wiring phenomenon: When the suture is too shallow or the tissue is fragile, the tissue is cut through by the tension on the thread.
- Formation of an inflammatory tract: Due to tissue softening from inflammation around the suture, the thread moves within the tissue.
Timing of suture removal
Section titled “Timing of suture removal”The table below shows the approximate timing for suture removal by tissue. It varies greatly depending on differences in blood vessel density and healing speed.
| Tissue | Approximate timing for suture removal |
|---|---|
| Eyelid skin | About 1 week |
| Conjunctiva | 2–3 weeks |
| Scleral wound / superficial keratoplasty | 1–3 months |
| Penetrating keratoplasty | 6 months to 1 year |
Because eyelid skin has abundant blood vessels and heals quickly, sutures can usually be removed after about 1 week. Penetrating keratoplasty involves avascular tissue, so healing takes a long time, and the sutures need to stay in place for 6 months to 1 year.
Q
How much does the timing of suture removal differ by tissue?
A
It varies greatly depending on tissue blood vessel density and healing speed. Eyelid skin is the shortest at about 1 week, while full-thickness corneal transplantation is the longest at 6 months to 1 year. Scleral wounds and superficial lamellar keratoplasty are generally 1 to 3 months.
5. Latest research and future prospects (research-stage reports)
Section titled “5. Latest research and future prospects (research-stage reports)”Han’s review (2025) analyzed 103 papers and systematically reviewed four advanced features of next-generation sutures (antibacterial properties, drug delivery, biodegradability, and wound regeneration) and two manufacturing techniques (electrospinning and 3D printing) 1).
Han (2025) organized diverse approaches to antibacterial sutures, including nanosilver particle coating, curcumin@ZIF-8 coating, and internal composite formation of regenerated silk fibroin and TiO2 1). These show excellent antibacterial activity against Staphylococcus aureus and Escherichia coli.
- Antibacterial sutures: Coatings such as nano-silver particles and curcumin@ZIF-8 are expected to reduce the risk of postoperative infection at the suture site 1).
- Drug delivery sutures: Nanofiber-based polycaprolactone sutures loaded with 8% levofloxacin did not lose strength, allowed 30 days of antibiotic delivery in mouse eyes, and have been reported to help prevent eye infections in a bacterial keratitis model (Parikh et al.) 1). Conventional monofilament sutures are said to lose more than 50% of their strength when drug-loaded.
- Biodegradable sutures: Natural absorbable sutures break down by protein degradation, while synthetic absorbable sutures break down by hydrolysis. Development of PLA-based biodegradable sutures is progressing 1).
- Wound-regenerative sutures: Sutures coated with bioactive glass/graphene oxide and reactive oxygen species–scavenging sutures are said to improve fibroblast attachment and proliferation and promote the secretion of angiogenic growth factors1).
- Electrospinning: a manufacturing technique that uses the high specific surface area of nanofibers to carry antimicrobial agents and can also impart biodegradability1).
- 3D printing: applications of computer-designed structural optimization and biomimicry are being explored1).
6. References
Section titled “6. References”- Han HR. Antibiotic Action, Drug Delivery, Biodegradability, and Wound Regeneration Characteristics of Surgical Sutures and Cutting-Edge Surgical Suture Manufacturing Technologies. Journal of functional biomaterials. 2025;16(4). doi:10.3390/jfb16040135. PMID:40278243; PMCID:PMC12028033.
- Kaur K, Gurnani B. Intermittent Exotropia. . 2026. PMID: 34662028.
- Ji L, Gandhi PN, Torres BS. Surgical Techniques and Outcomes in the Management of Pediatric Eyelid Burns: A Systematic Review. Ophthalmic Plast Reconstr Surg. 2025;41(3):245-249. PMID: 39749813.