Ophthalmic Surgical Instruments: Identification, Uses and Viva Questions
Last updated: November 2026
Instrument identification is a fixed part of MS and DNB ophthalmology practicals, and a favourite quick-fire viva. The examiner hands you an instrument and expects four things: its name, how you recognise it, what it is used for, and one follow-up fact. This page groups the common instruments by the operation they belong to, so you learn them the way you meet them in theatre.
How to answer an instrument viva
- Name it fully, with the eponym if there is one ("Barraquer wire speculum").
- Describe it in one line: what you hold, the working end, any lock, tooth, curve or angle.
- Give its uses, main use first.
- Add one point that shows experience: a precaution, an alternative, or how to check it before use.
Hold the instrument as you would in surgery while you talk. Examiners notice whether you know which way up a Sinskey hook or a keratome goes.
The basic eye set
| Instrument | How to recognise it | Uses | Viva point |
|---|---|---|---|
| Barraquer wire speculum | Single springy wire, two curved loops, no screw | Keeps the lids open in most anterior segment surgery | Light and cheap, but cannot be adjusted; avoid in eyes with raised orbital pressure or open globe |
| Universal (adjustable) speculum | Two blades with a screw or ratchet to set the opening | Wider, controlled exposure (MSICS, trabeculectomy, retina) | Do not open it wider than needed; it presses on the globe and raises IOP |
| Plain (non-toothed) forceps | Serrated tips, no teeth | Holding conjunctiva and delicate tissue | Teeth tear conjunctiva; use plain forceps on it |
| Toothed forceps (e.g. St Martin) | 1×2 teeth at the tip | Holding sclera, skin, Tenon's | Never on conjunctiva or iris |
| Colibri (0.12 mm) forceps | Fine 1×2 teeth with a tying platform; very fine tips | Holding the cornea and sclera while suturing or making incisions | The 0.12 refers to the tooth size in mm; protect the tips |
| McPherson tying forceps | Angled, smooth, flat tying platforms | Tying fine sutures (10-0 nylon); handling IOL haptics | Smooth jaws do not crush the suture |
| Castroviejo needle holder | Fine curved jaws, often with a lock | Microsuturing with 8-0 to 10-0 needles | Use the locking type for the surgeon, non-locking for fine control |
| Barraquer needle holder | Curved, spring handle, no lock | Fine corneal and conjunctival suturing | Lighter than Castroviejo; no lock to release |
| Westcott scissors | Spring handle, short blunt or sharp blades | Conjunctival and Tenon's dissection | Also called tenotomy scissors in some sets |
| Vannas scissors | Very fine, straight or angled spring scissors | Cutting iris, capsule, fine sutures; iridectomy in trabeculectomy | The finest scissors in the set; never cut thick tissue |
| Corneal scissors (Castroviejo) | Curved blades, right and left pair | Extending a corneal section (ECCE, keratoplasty) | Comes in right and left so the cut follows the limbus |
| Bard-Parker handle | Flat handle that takes detachable blades (No. 11, 15) | Skin incisions (lids, DCR); No. 15 for most lid work | No. 11 is pointed, No. 15 is curved |
| Wet-field (bipolar) cautery | Fine bipolar tips on a cable | Haemostasis of episcleral vessels | Use the minimum needed; scleral shrinkage and wound leak follow over-cautery |
Cataract: phaco and MSICS instruments
| Instrument | How to recognise it | Uses | Viva point |
|---|---|---|---|
| Keratome (angled slit knife) | Angled, flat, diamond or arrow-shaped steel blade, usually 2.2–2.8 mm | Main clear corneal incision in phaco | Width is marked on the hub; the incision should be self-sealing (triplanar) |
| Side-port blade (15°) | Narrow pointed blade at 15° | Paracentesis for the second instrument and for AC reformation | About 1 mm wide; place 60–90° from the main port |
| Crescent knife | Bevel-up, rounded crescent blade | Scleral or sclerocorneal tunnel in MSICS and SICS | Dissects in one lamellar plane; keep the blade flat |
| MVR blade (20G or 23G) | Spear-shaped, double-edged, pointed | Sclerotomies in vitrectomy; AC entry | Microvitreoretinal blade |
| Cystitome | 26G needle bent at the tip and again at the hub | Starting the capsulotomy; can-opener capsulotomy | Made on the table from a disposable needle |
| Utrata forceps | Angled forceps with fine pointed grasping tips | Completing a continuous curvilinear capsulorhexis | Grasp the flap near the base and re-grasp often |
| Sinskey hook | Fine angled shaft ending in a small hook | Rotating the nucleus, dialling the IOL, manipulating the iris | Held with the hook pointing down into the bag |
| Kuglen hook (iris manipulator) | Small two-pronged or hooked tip | Pushing or pulling the iris, dialling the IOL | Useful to retract the iris edge in small pupils |
| Chopper (e.g. Nagahara, Chang) | Angled tip, sharp or blunt, inner cutting edge | Splitting the nucleus during phaco chop | Horizontal choppers go round the equator; vertical ones go straight down |
| Simcoe cannula | Two-way cannula: irrigation line and aspiration port | Irrigation-aspiration of cortex in ECCE and MSICS | Aspiration port must face up to avoid sucking the capsule |
| Rycroft cannula | Fine angled 27G or 30G cannula | Hydrodissection, AC reformation, stromal hydration | Inject gently; a fluid wave should pass behind the nucleus |
| Wire vectis (lens loop) | Flat loop with or without irrigation ports | Delivering the nucleus in MSICS (irrigating vectis for hydroexpression) | Slide it under the nucleus, keeping the posterior capsule safe |
| Lens-holding (Kelman-McPherson) forceps | Angled forceps with smooth flat jaws | Holding and inserting a rigid PMMA IOL | Do not crush the optic |
| IOL injector and cartridge | Plunger and folding cartridge | Inserting a foldable IOL through a small incision | Check the leading haptic is forward and the lens is not upside down |
| Capsular tension ring injector | Fine plunger with a hooked tip | Inserting a capsular tension ring in weak zonules | Put the ring in after the capsulorhexis and before or after phaco, never with a capsular tear |
| Iris hooks or Malyugin ring | Flexible nylon hooks or a square polypropylene ring with an injector | Enlarging and holding a small pupil | Malyugin ring sizes 6.25 and 7.0 mm |
Glaucoma surgery
| Instrument | How to recognise it | Uses | Viva point |
|---|---|---|---|
| Kelly Descemet punch | Fine punch with a small biting jaw | Removing a block of the inner scleral flap (sclerostomy) in trabeculectomy | Gives a clean, sized ostium; an alternative is cutting with a blade and Vannas |
| Luntz-Dodick punch | Smaller, angled version of the Descemet punch | Sclerostomy in trabeculectomy | Same job as Kelly punch |
| Crescent blade | As above | Making the partial-thickness scleral flap | Flap about half scleral thickness |
| MMC sponges | Small cellulose sponges (on a tray, not an instrument) | Applying mitomycin C under the conjunctiva | Keep MMC away from the cut conjunctival edge; wash out with BSS |
Lids, lacrimal and oculoplastic instruments
| Instrument | How to recognise it | Uses | Viva point |
|---|---|---|---|
| Chalazion clamp | Ring (or oval plate) on one blade, solid plate on the other, with a screw | Holding the lid everted and bloodless for chalazion incision and curettage | Incise vertically on the conjunctival side to avoid cutting across meibomian glands |
| Chalazion scoop (curette) | Small sharp-edged cup on a handle | Scraping out chalazion contents | Send recurrent "chalazia" in elderly patients for histology (sebaceous carcinoma) |
| Desmarres lid retractor | Curved, saddle-shaped plate on a handle | Everting or retracting the lid for examination and surgery | Double eversion of the upper lid to look in the fornix |
| Jaeger lid plate | Flat horn or metal plate | Protecting the globe and giving a firm base during lid surgery | Used in entropion and trichiasis surgery |
| Nettleship punctum dilator | Short conical pointed tip on a handle | Dilating the punctum before probing or syringing | Insert vertically 2 mm, then turn horizontal along the canaliculus |
| Bowman lacrimal probes | Double-ended fine probes in graded sizes (0000 to 8) | Probing the canaliculi and nasolacrimal duct (CNLDO) | Probing in infants is usually done around 12 months if obstruction persists |
| Lacrimal cannula | Fine blunt bent cannula on a syringe | Syringing the lacrimal passages | Regurgitation through the opposite punctum suggests a common canalicular or NLD block |
| Freer periosteal elevator | Double-ended flat blades, one sharp one blunt | Raising periosteum in DCR, orbital floor repair | Work under the periosteum to stay in a bloodless plane |
| Kerrison bone punch | Angled biting punch with a footplate | Removing bone to make the osteotomy in DCR | Keep the footplate under the bone, away from the nasal mucosa |
| Lambert chalazion forceps | Variant of chalazion clamp | Same as chalazion clamp | Name varies between hospitals; describe the parts |
| Beer cilia (epilation) forceps | Flat broad smooth tips | Epilating misdirected lashes (trichiasis) | Lashes regrow in 4–6 weeks; electrolysis or surgery for recurrence |
| Snellen entropion clamp | Clamp with a plate and bar, screw fixation | Holding the lid during entropion surgery | Historical but still in some sets |
Squint, enucleation and evisceration
| Instrument | How to recognise it | Uses | Viva point |
|---|---|---|---|
| Muscle hook (Jameson, von Graefe) | Blunt hook; Jameson has a bulb at the tip, von Graefe is plain | Isolating an extraocular muscle | Hook the muscle from the side, sweeping posteriorly then forward |
| Castroviejo calipers | Two sliding pointed arms with a mm scale | Measuring recession or resection distance, keratoplasty and limbus distances | Measure from the original insertion or the limbus, as your technique states |
| Enucleation scissors | Strong curved blunt scissors | Cutting the optic nerve in enucleation | Cut at least 10 mm of nerve in retinoblastoma |
| Enucleation spoon | Spoon with a notch for the nerve | Lifting the globe forward for nerve section | Avoid excessive traction (oculocardiac reflex) |
| Evisceration spoon (curette) | Sharp-edged spoon | Scooping out uveal tissue in evisceration | All uveal tissue must be removed to reduce the risk of sympathetic ophthalmia |
| Orbital implant introducer | Funnel or sheet | Placing a spherical implant in the socket | Implant size usually 18–22 mm |
Cornea, retina and other instruments
| Instrument | How to recognise it | Uses | Viva point |
|---|---|---|---|
| Corneal trephine (e.g. Hessburg-Barron vacuum trephine) | Circular blade, often with a suction ring and graduations | Cutting a circular corneal button in keratoplasty | Donor button usually 0.25–0.5 mm larger than the recipient bed |
| Foreign body spud and gouge | Small flat or rounded blade; motorised burr for rust rings | Removing corneal foreign bodies and rust rings | Use a 26G needle tangentially at the slit lamp; check eversion of the upper lid |
| Scleral depressor (Schepens) | Thimble or pen type with a small rounded tip | Indenting the sclera during indirect ophthalmoscopy | Never press through the closed lid on a recently operated or open globe |
| Indirect ophthalmoscope with +20 D and +28 D lenses | Headset with a separate hand-held condensing lens | Examining the peripheral retina; laser delivery (LIO) | +20 D: magnification about 3×, field about 45°; +28 D: about 2×, wider field |
| Vitrector and endo-illumination probe | Fine probes on cables (23, 25 or 27G) | Vitrectomy | Higher cut rates reduce traction on the retina |
| Fine-needle aspirate / vitreous tap set | 23–25G needle on a syringe | Vitreous biopsy in endophthalmitis | Send for Gram stain, culture and PCR before injecting antibiotics |
Care, checking and sterilisation
- Inspect tips under the microscope before surgery: bent forceps tips and blunt scissors cause most "instrument" complications.
- Clean immediately after use: dried viscoelastic and blood inside cannulas and handpieces are a recognised cause of toxic anterior segment syndrome (TASS).
- Steam autoclaving is the standard for metal instruments; delicate tips should be protected in a tray with silicone mats. Blades and cannulas are single-use.
- See sutures, needles and sterilisation for suture sizes, needle types and sterilisation methods.
Photographs coming: clinical photographs of each instrument will be added to this page.
Where residents slip
- Calling every speculum a "Barraquer": describe the wire versus adjustable type.
- Using toothed forceps on conjunctiva in the viva answer.
- Forgetting single-use items (blades, cannulas) when asked about sterilisation.
- Not knowing which side of a crescent knife faces up (bevel up).
Test yourself: flip cards
Quick quiz
Related: Sutures, Needles and Sterilisation in the Eye Theatre, Phacoemulsification Step by Step: A Beginner's Guide, Manual Small Incision Cataract Surgery (MSICS): Steps and Pitfalls, Lateral Canthotomy, AC Paracentesis and Pupil Examination: How-To for Residents, Instruments in Ophthalmology: Who Invented What.
Key sources
- American Academy of Ophthalmology. Basic and Clinical Science Course, Section 11: Lens and Cataract; Section 7: Oculofacial Plastic and Orbital Surgery (current editions)
- Mamalis N, et al. Toxic anterior segment syndrome: update on the most common causes. J Cataract Refract Surg. 2012;38:1902-1910
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