Sutures, Needles and Sterilisation in the Eye Theatre
Last updated: November 2026
Every eye surgeon needs to know which suture to ask for, why the needle shape matters, and how instruments are made safe. These are also favourite viva questions.
Sutures
| Suture | Type | Typical eye uses |
|---|---|---|
| Polyglactin 910 (Vicryl) | Absorbable, braided; absorbed in about 2–3 months | Conjunctiva (8-0), muscle surgery (6-0), lid and subcutaneous layers |
| Polyglycolic acid (Dexon) | Absorbable, braided | Similar to Vicryl |
| Catgut (plain or chromic) | Absorbable, natural, more reaction | Largely replaced |
| Nylon (Ethilon) | Non-absorbable, monofilament; slowly loses strength over years | 10-0 for cornea (keratoplasty, wound repair), 9-0 for scleral flaps; skin |
| Polypropylene (Prolene) | Non-absorbable, monofilament, very durable | IOL scleral or iris fixation (10-0 or 9-0), iris repair |
| Silk | Non-absorbable, braided, easy to handle, more reaction | Traction (bridle) sutures, lids (6-0, 4-0) |
| Polyester (Mersilene) | Non-absorbable, braided, strong | Frontalis sling, scleral buckle fixation (5-0) |
Size: the more zeros, the finer the suture (10-0 is finer than 6-0).
Needles
| Needle | Cross-section and use |
|---|---|
| Spatulated | Flat top and bottom, cuts at the sides; splits lamellae: cornea and sclera (the standard ophthalmic needle) |
| Reverse cutting | Cutting edge on the outer curve; tough tissue such as skin and tarsus |
| Conventional cutting | Cutting edge on the inner curve; can cut out of tissue |
| Taper (round-bodied) | Pierces without cutting; soft tissue such as conjunctiva, vessels |
Sterilisation and disinfection
| Method | Details | Used for |
|---|---|---|
| Steam autoclave | 121 °C at 15 psi for 15–20 minutes, or 134 °C for 3–4 minutes (flash cycles only for emergencies) | Most metal instruments |
| Ethylene oxide (ETO) | Low temperature gas; needs long aeration because the gas is toxic | Heat-sensitive items, IOL packaging |
| Hydrogen peroxide plasma | Low temperature, fast, no toxic residue | Heat-sensitive instruments, cables |
| Gamma irradiation | Industrial | Single-use items, sutures, blades |
| High-level disinfection | 2% glutaraldehyde or ortho-phthalaldehyde; not sterilisation | Tonometer prisms are usually cleaned with alcohol wipes or disposable covers |
TASS: toxic anterior segment syndrome
- A sterile inflammation within 12–48 hours of anterior segment surgery: diffuse limbus-to-limbus corneal oedema, fibrin, little pain.
- Causes: detergent or enzyme residue on instruments, wrong concentrations of intracameral drugs, preservatives, endotoxins.
- Differs from endophthalmitis by early onset, minimal pain and no vitritis. Treat with intensive topical steroids; investigate the theatre process if more than one case.
Where residents slip
- Asking for Vicryl to close a corneal wound.
- Using a cutting needle on the cornea.
- Confusing TASS with endophthalmitis.
Test yourself: flip cards
Related: Endophthalmitis: Types, Organisms and Management, How to Prepare for Cataract & LASIK Surgery, Basic Sciences.
Key sources
- American Academy of Ophthalmology and ASCRS. Guidelines for the cleaning and sterilization of intraocular surgical instruments. 2018
- Mamalis N, et al. Toxic anterior segment syndrome. J Cataract Refract Surg. 2006;32:324-333
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