OPHTHALMIC INSTRUMENTS · MATERIALS, DRUGS AND EQUIPMENT · STUDENT STUDY NOTES
Ophthalmic equipment ranges from a visual-acuity chart and pen torch in a primary-care room to a slit lamp, tonometer, operating microscope and finely engineered microsurgical instruments in a specialist eye unit. Knowing an instrument means understanding its name, structure, purpose, limitations, level of care and the safety steps needed before it touches a patient. This guide combines a practical eye-clinic equipment framework with every named instrument in the supplied 37-slide SlideShare deck.
Learning scope: This is a recognition and clinical-use guide for medical and emergency-care students. It supports examination, equipment identification, safe handling and referral decisions. It is not an instruction manual for surgery, tonometry, lacrimal probing or any invasive procedure. Use instruments only within your training, competency and local protocol.
Learning objectives
By the end of this lesson, you should be able to:
- Classify common eye-care equipment by purpose and level of service.
- Select the basic tools needed to measure vision and perform a safe first examination.
- Explain the roles of common diagnostic instruments and accessories.
- Identify each named instrument in the supplied SlideShare deck and link it to its principal use.
- Recognise legacy techniques, potential hazards and the limits of a single instrument or measurement.
- Describe basic principles of cleaning, disinfection, sterilisation, maintenance and infection prevention.
At a glance: what the equipment is for
| Equipment group | Main question it helps answer | Examples |
|---|---|---|
| Vision testing | How well can each eye resolve detail, at distance and near? | Distance and near charts, occluder, pinhole, trial lenses |
| Illumination and magnification | What can be seen on gross inspection or with magnification? | Pen torch, hand lens, loupe, slit lamp |
| Intraocular pressure and angle | What is the measured pressure, and what does the drainage angle look like? | Goldmann or portable tonometer, gonioscopy lens |
| Posterior segment | What can be seen of the optic disc, vessels, macula and retina? | Direct and indirect ophthalmoscopes, condensing lens, fundus camera |
| Refraction and function | What refractive error, alignment, field or sensory deficit is present? | Retinoscope, trial set, Maddox rod, Amsler grid, perimeter |
| Procedure and surgery | How does a trained clinician expose, stabilise, incise, grasp, measure or repair tissue? | Specula, forceps, scissors, blades, cannulae, retractors |
Match the kit to the level of care
There is no single instrument list that fits every clinic. The right inventory depends on the conditions the service is expected to assess, the staff’s training, available electricity and maintenance, referral pathways, infection-control capacity and national standards. WHO’s primary-eye-care equipment list is a useful low-resource model; comprehensive refraction and specialist surgery require additional staff and equipment.
| Setting | Core capability | Typical equipment |
|---|---|---|
| Community / primary care | Screen vision, inspect externally, recognise danger signs, give permitted basic care and refer | Distance and near vision charts, occluder, pinhole, torch, hand magnifier, eye shield, appropriate eye pads, epilation forceps where trained and indicated, hand hygiene supplies |
| Eye outpatient / district eye unit | Detailed anterior-segment and fundus examination, basic refraction, pressure assessment and selected procedures | Slit lamp, direct ophthalmoscope, indirect ophthalmoscope and lens, tonometer, fluorescein, trial lenses or refraction equipment, gonioscopy lens, lacrimal and foreign-body equipment as locally supported |
| Operating theatre / specialist unit | Microsurgery under trained operators, sterile field, monitoring and recovery | Operating microscope, procedure-specific sterile instrument sets, illumination, suction and irrigation, cautery where required, anaesthesia and resuscitation equipment, sterilisation and instrument-tracking systems |
| Optical / visual-function service | Refraction, spectacles, binocular and visual-field assessment, low-vision support | Retinoscope, trial frame and lenses, phoropter or refractor, focimeter, keratometer, charts, stereopsis and colour tests, perimeter, Amsler grid, low-vision charts |
The basic primary eye-care kit
Basic equipment has high value because it makes the first examination more consistent. WHO’s model specifies eye charts, a torch, magnification, an eye pad and shield, and epilation forceps, alongside teaching materials and locally appropriate supplies. A service should adapt the model to its workflow rather than treating an old procurement list as a substitute for current Ministry of Health guidance.
| Item | What it does | Use and safety point |
|---|---|---|
| Distance visual-acuity chart | Tests recognition of progressively smaller optotypes at a known distance. | Use a well-lit chart at its specified distance, commonly 6 m for a traditional Snellen chart. Test each eye separately with the fellow eye covered without pressing on it; record correction worn, test distance and the smallest line read. Use a tumbling-E, symbols or language-appropriate chart when letters are unsuitable. |
| Near-vision chart | Assesses ability to resolve print or symbols at a standard near distance. | Hold at the chart’s marked distance with the patient’s usual near correction when appropriate. Record the distance and type of chart; do not compare results taken at different distances as though they were equivalent. |
| Occluder and pinhole | The occluder isolates each eye; a pinhole can show whether reduced acuity may improve when peripheral rays are excluded. | Do not let the patient squeeze the eyelid or press on the globe. Improvement through pinhole suggests an optical/refractive contribution, but it does not rule out ocular disease and is not a full refraction. |
| Pen torch | Provides a portable light for pupil responses, gross inspection and selected external-eye checks. | Check batteries and illumination. Use a brief, appropriate beam and compare pupils in a consistent way. A torch does not replace slit-lamp magnification or a fundus examination. |
| Hand magnifier or loupe | Magnifies lids, lashes, conjunctiva and visible surface structures. | Useful for a primary-level assessment and suspected superficial foreign bodies. A binocular loupe frees the hands; neither tool gives the optical section and stereoscopic detail of a slit lamp. |
| Eye shield | Rigid protection that keeps pressure off a potentially injured eye. | For suspected open-globe injury, use a rigid shield without pressure and arrange emergency ophthalmology care. Avoid manipulating the eye or applying a pressure dressing. |
| Eye pad and tape | Can protect selected closed-surface injuries or support care when specifically indicated. | Do not routinely cover a suspected infected eye or use a pad to compress a potentially open globe. Keep supplies clean; tape should not pull the lids shut over an eye that needs urgent assessment. |
| Epilation forceps | Fine forceps can temporarily remove an in-turned lash in selected trichiasis care. | Only trained personnel should use them, with suitable lighting and magnification. Epilation is temporary and does not correct entropion; patients with trichiasis need referral and follow-up. Do not cut lashes as a substitute. |
Equipment for a comprehensive eye examination
Anterior segment and external eye
The slit-lamp biomicroscope combines stereoscopic magnification with an adjustable, narrow beam. The beam can be widened for general viewing or narrowed to create an optical section through transparent structures. A systematic examination covers the lids and lashes, conjunctiva, sclera, cornea, anterior chamber, iris, pupil and lens. A cobalt-blue filter is used with fluorescein to make epithelial staining easier to see; a red-free filter can help show vessels. Handheld condensing lenses allow a trained examiner to view the fundus through the slit lamp. Gonioscopy requires a contact lens and appropriate technique to visualise the iridocorneal angle.
Common accessories include fluorescein strips or sterile fluorescein solution, topical anaesthetic used only for examination/procedures according to protocol, cotton-tipped applicators, a lid eversion aid, foreign-body instruments, lacrimal syringing equipment and measuring calipers. These do not all belong in a basic first-aid kit. Use single-patient consumables where required; prevent applicator or bottle tips from contacting the ocular surface or lashes.
Pressure, angle and glaucoma assessment
A tonometer estimates intraocular pressure (IOP). Goldmann applanation tonometry is mounted on a slit lamp and measures the force needed to flatten a defined small corneal area. Portable applanation devices such as Perkins and rebound, indentation or handheld electronic devices may be useful in different settings. The readings are not interchangeable without considering device type, technique, corneal properties and calibration. IOP is only one part of glaucoma assessment: optic-nerve appearance, visual fields, angle findings, corneal thickness and the clinical context also matter.
Contact tonometry requires the device tip and any reusable prism to be inspected, cleaned and disinfected exactly as specified by the manufacturer and local infection-prevention policy. A cracked or damaged prism can injure the cornea and harbour contamination. Avoid compressing the globe with fingers or lids during measurement because external pressure can alter the result. A measured IOP should be interpreted with the method and quality of the reading recorded.
Posterior segment and imaging
A direct ophthalmoscope provides a magnified, upright, relatively narrow view of the fundus. A binocular indirect ophthalmoscope with a condensing lens gives a wider, stereoscopic view of the retina and peripheral fundus, typically with an inverted image. A 78D, 90D or other slit-lamp fundus lens is used for posterior-segment viewing at the slit lamp. Fundus cameras document the optic disc and retina; optical coherence tomography (OCT) provides cross-sectional imaging of selected retinal and optic-nerve structures. These imaging systems complement clinical examination and do not replace it.
Refraction, alignment and visual function
Refraction equipment may include a retinoscope, trial frame with trial lenses, lens bars, a phoropter/refractor, autorefractor, keratometer and focimeter. A retinoscope estimates refractive error from the movement of the retinal reflex; subjective refraction refines the patient’s best correction. Keratometers estimate central corneal curvature, while a focimeter measures an existing spectacle lens. For function, a colour-vision test, Amsler grid, near and distance charts, stereopsis tests, prism bars, Maddox rod and visual-field perimeter answer different questions. No one test screens every visual pathway or eye disease.
A safe equipment-based examination workflow
- Prepare the room and patient: check hand hygiene, lighting, chart distance, instrument function, patient comfort, interpreter/accessibility needs and any required personal protective equipment.
- Start with vision: record presenting visual acuity in each eye separately, with usual correction where relevant; use pinhole when acuity is reduced and document what was tested.
- Inspect before touching: assess facial symmetry, lids, lashes, conjunctiva, cornea and pupils with adequate light. If there is trauma or possible open globe, stop routine manipulation, shield without pressure and obtain urgent specialist help.
- Choose the examination tool: torch and loupe for a basic screen; slit lamp for magnified anterior-segment assessment; ophthalmoscope or indirect viewing for the fundus; tonometer only when indicated and when the operator is competent.
- Clean between patients: follow manufacturer instructions for patient-contact surfaces, chin/forehead rests, reusable lenses, tonometer prisms and instruments. Keep sterile items separate from clean non-sterile equipment.
- Record both result and limitation: include device/method where it affects interpretation, findings, uncertainty, actions, referral urgency and any equipment problem that may have influenced the examination.
Specialist ophthalmic surgical instruments in the supplied deck
The supplied SlideShare deck is an instrument-recognition resource rather than a current universal operating-tray checklist. It names instruments used in cataract, corneal, glaucoma, lacrimal, eyelid, strabismus, enucleation and evisceration procedures. The same instrument may be used differently in different operations, and instrument names or designs vary between services. All invasive use is for a trained and supervised eye-care surgeon.
Incision, corneal work and measurement
| Instrument | Recognition / principal role | Teaching point |
|---|---|---|
| Side-port entry blade | Small straight blade used by a surgeon to create an accessory clear-corneal entry in procedures such as phacoemulsification. | It is distinct from the larger main-incision blade. Blade geometry and wound construction are procedure-specific. |
| Keratome | Broader, often diamond-shaped blade for a planned corneal entry into the anterior chamber in cataract surgery. | Modern phaco and manual small-incision cataract techniques depend on controlled wound architecture; handling belongs to supervised surgical training. |
| Crescent knife | Blunt-tipped, bevelled dissector used to form a scleral-corneal tunnel in selected cataract approaches and some glaucoma procedures. | It separates tissue layers rather than functioning as a pointed entry blade. Exact use depends on the operative technique. |
| Corneal trephine | Hollow circular cutting instrument used to mark or create a controlled circular corneal button, particularly in keratoplasty. | Diameter and depth are chosen by the surgeon for the procedure; it is not an examination tool. |
| Trephine blade | Blade associated with a trephine system or used to complete a trephined cut, depending on the set. | Recognise the cutting edge and match it to the correct handle/system. Do not assume all trephines have an interchangeable blade. |
| Corneal / section-enlarging scissors | Fine scissors for enlarging selected corneal or corneoscleral incisions; the deck also describes use in glaucoma filtration surgery. | Some historical cataract applications relate to extracapsular or intracapsular extraction, which are less common where phacoemulsification is available. |
| Corneoscleral forceps | Fine grasping forceps used to stabilise a corneal or scleral wound edge during suturing in cataract, glaucoma, corneal repair and keratoplasty. | Atraumatic control is critical: cornea and sclera are delicate, and toothed versus smooth tips are selected for the tissue and task. |
| Castroviejo caliper | Small measuring caliper used in eye surgery and examination, for example to measure corneal diameter, visible iris diameter, lid position or planned surgical distances. | Read the scale and confirm the caliper is zeroed and functioning; measurement landmarks must be standardised. |
Cataract, lens and intraocular manipulation
| Instrument | Principal role | Clinical context / caution |
|---|---|---|
| IOL dialer | Hook-like instrument that gently rotates or positions an intraocular lens (IOL) haptic within the capsular bag or sulcus. | Modern IOL designs and insertion systems differ. Avoid confusing a dialer with a chopper or lens hook. |
| Chopper | Phacoemulsification instrument used with a phaco tip to divide and manipulate the cataract nucleus. | Different chopper tips have different cutting edges and angles; this is a microsurgical instrument requiring direct training. |
| Wire vectis | Loop-shaped support/extraction instrument used in selected lens extraction situations, including delivery of a nucleus or a dislocated lens. | Primarily associated with older extracapsular or intracapsular approaches; not a routine modern phaco tool. |
| Capsulorhexis forceps | Fine forceps used by a surgeon to grasp and control the anterior lens capsule during capsulorhexis creation. | The continuous circular opening is a central cataract-surgery step. Forceps design and technique differ; this guide does not teach the manoeuvre. |
| Iris repositor | Double-ended blunt/bladed instrument for gentle iris repositioning in the anterior chamber or selected synechiae management. | Do not push on or manipulate the iris outside a trained operative setting; damage can cause bleeding, inflammation or pupil distortion. |
| Simcoe cannula | Handheld irrigation-aspiration cannula used to remove residual lens matter in manual extracapsular cataract surgery. | It is a fluid pathway instrument, not a needle for injection. Modern systems may use automated irrigation-aspiration handpieces. |
| IOL holding forceps | Smooth, short, blunt forceps designed to hold the optic of certain rigid polymethyl methacrylate (PMMA) lenses during placement. | Use the forceps matched to the lens type; a rigid-IOL instrument is not automatically suitable for a foldable IOL. |
| Kelman–McPherson forceps | Fine angled forceps used in some cataract procedures to grasp an IOL haptic, manipulate capsule or tie sutures. | Its applications overlap with other fine forceps, but instrument selection depends on tip geometry and the specific task. |
| Needle holder / needle-holding forceps | Fine locking or spring-action holder used to control a microsurgical needle while placing sutures. | The slide names it without a detailed caption. Match jaw size to the needle; gripping the needle incorrectly can damage it or compromise control. |
| Lens injector | Cartridge-and-plunger system that delivers a compatible foldable IOL through a small incision. | Lens, cartridge, loading method and injector must be compatible. Incorrect loading or reuse can damage the lens or contaminate the eye. |
| Lens expressor | Blunt curved hook historically used to apply controlled external pressure during older lens-delivery techniques or to assist with a vectis. | This is a legacy instrument in many settings. It is not a general-purpose tool and is not a substitute for modern phaco/IOL techniques. |
| de Wecker’s scissors | Fine spring scissors with short blades used in selected intraocular tasks such as iridectomy/iridotomy or cutting membranes and prolapsed vitreous under surgical control. | These are specialist scissors; names, patterns and current role vary. The surgeon chooses a suitable instrument for the tissue and operation. |
Exposure, eyelid, lacrimal and extraocular instruments
| Instrument | Principal role | Clinical context / caution |
|---|---|---|
| Wire eye speculum | Spring-wire retractor that holds the lids apart to expose the eye for examination or an operation. | Choose a size and design that fit without excessive pressure. A speculum does not protect the cornea from a sharp instrument. |
| Superior rectus holding forceps | Curved, often toothed forceps used to hold the superior rectus region or a bridle suture and help stabilise the globe during selected operations. | Slides 13 and 14 show the same named instrument, with one slide serving as an additional illustration; it is counted once here. |
| Strabismus / muscle hook | Blunt hook with a guarded tip used by the surgeon to identify and engage an extraocular muscle during strabismus or selected orbital procedures. | The guard helps reduce slippage. A muscle hook and lens expressor may look similar but have different tip geometry and intended tissue. |
| Bowman lacrimal probes | Set of graduated, blunt-ended probes used to assess or traverse the lacrimal drainage pathway in selected procedures. | Probing is not a bedside task for an untrained examiner. False passage, trauma and infection are possible; use specialist technique and indication. |
| Bone punch | Rongeur-like instrument that removes small pieces of bone to enlarge a bony opening during dacryocystorhinostomy (DCR). | Used in lacrimal surgery by trained teams, with attention to adjacent nasal and orbital structures. |
| Lacrimal sac dissector and curette | Double-ended tool with a blunt dissector at one end and curette at the other, used in lacrimal sac surgery. | Recognise the two working ends; it is a procedural instrument and must be processed for the intended sterile field. |
| Müller self-retaining lacrimal wound retractor | Small pin retractor that holds skin edges apart during lacrimal sac surgery such as DCR or dacryocystectomy. | It improves exposure but its pins can injure tissue if placed or tensioned incorrectly. |
| Lid / entropion clamp | Clamp or spatula-type device that stabilises eyelid tissue and can support haemostasis in selected lid operations. | A self-retaining clamp may reduce the need for an assistant but can narrow the field or cause pressure injury if applied too tightly. |
| Chalazion clamp | Screw-adjusted clamp with a disc and ring that isolates a chalazion and helps control bleeding during incision and curettage. | It is used by a trained clinician after confirming the lesion and consent. The clamp’s orientation and pressure matter. |
| Ptosis clamp | Locking clamp with shaped jaws for grasping levator tissue during selected ptosis operations. | Ptosis repair depends on cause, levator function and ocular-surface status; the clamp is not used to diagnose ptosis. |
| Optic nerve guide / enucleation spoon | Slotted, spoon-like guide associated with isolating the optic nerve during enucleation. | Recognise the association with globe removal; enucleation is a specialist operation with a separate clinical lesson. |
| Evisceration curette | Shallow, blunt-edged cup-shaped curette associated with removal of intraocular contents during evisceration. | Enucleation removes the globe; evisceration removes intraocular contents while retaining the scleral shell. They are distinct operations. |
| Evisceration stand | Support used to hold the removed ocular contents/eye specimen after evisceration for handling or demonstration. | This is an adjunct, not an instrument used to enter the eye. Label and handle specimens according to clinical and pathology protocol. |
Alignment test in the deck
Maddox rod: a red, grooved cylindrical lens that converts a point light into a line. With appropriate fixation and cover testing, the perceived line’s position relative to the light helps assess ocular deviation, particularly in selected phoria measurements. It is a diagnostic tool, not a surgical instrument. Results depend on correct distance, fixation, dissociation, prism use and the examiner’s interpretation; it does not replace a complete motility examination.
Coverage note: the deck contains 37 slides: a title slide, named instrument slides, a repeated superior-rectus-forceps image, and a final dated slide without an independently readable instrument label. All distinct named instruments are included above; the final unlabeled slide is not assigned a speculative name.
How to identify an instrument at a practical station
- Describe shape first: blade, hook, loop, forceps, scissor, clamp, cannula, probe, retractor, measuring device or optical instrument.
- Look at the tip: sharp versus blunt, toothed versus smooth, curved versus straight, single versus double-ended, guarded versus unguarded.
- Link design to tissue: a trephine makes a circular corneal cut; a speculum separates lids; a cannula carries fluid; a caliper measures; a forceps grasps; a hook engages a structure.
- State one principal use and one caution: this shows applied understanding and avoids the unsafe claim that a tool can be used for any similar-looking task.
- Place it in time: say whether the use is routine in current surgery, technique-dependent, specialised or mainly associated with older extraction methods.
Cleaning, disinfection, sterilisation and maintenance
Ophthalmic instruments are small, delicate and often contact the ocular surface or enter a sterile field. A broken tip or residue may cause serious harm. Reprocessing follows the manufacturer’s instructions for use, device classification and the facility’s infection-prevention policy; do not improvise concentrations, soaking times, heat exposure or lubrication.
- At point of use: keep used instruments from drying with soil on them, protect sharp tips, separate sharps and delicate optics, and send them promptly for the validated cleaning process.
- Cleaning before disinfection/sterilisation: remove soil from hinges, jaws, lumens and cannulae using approved methods. Cleaning does not equal sterilisation.
- Choose the correct reprocessing level: critical instruments that enter sterile tissue or the vascular system require sterilisation; items contacting mucous membranes or non-intact skin require at least the reprocessing level set by national policy and the device instructions.
- Inspect before use: confirm alignment, smooth movement, secure joints, intact insulation where applicable, sharpness only where intended, no corrosion, no cracks, unobstructed cannulae and clean optical surfaces.
- Protect tonometer tips and lenses: use only manufacturer-approved cleaning/disinfection for the specific prism or lens. Inspect contact tonometer prisms for chips or cracks before every use.
- Maintain powered equipment: check cables, plugs, batteries, bulbs, charging, calibration and service records. Remove malfunctioning equipment from use and label it for repair.
- Store safely: keep instruments dry and protected in the correct tray or case; use tip guards and avoid stacking heavy items on delicate optics or forceps.
Equipment maintenance is a patient-safety function, not merely an administrative task. A slit lamp with a misaligned beam, an uncalibrated tonometer, a dim torch, a damaged IOL injector or a blocked irrigation cannula can undermine the examination or operation. Record servicing, calibration, breakdowns and return-to-service checks.
Common errors and safety reminders
| Error | Why it matters | Better practice |
|---|---|---|
| Using a vision chart at an unknown distance or in poor lighting | The score cannot be interpreted or compared reliably. | Set the chart distance and illumination; record the test conditions and chart type. |
| Calling a pinhole result a diagnosis | Improvement may reveal refractive contribution but does not exclude ocular pathology. | Continue assessment and arrange refraction or referral as indicated. |
| Pressing on the globe while holding the lids or using a shield | Pressure can worsen an open-globe injury or distort IOP measurement. | Use a no-pressure shield for suspected penetrating injury; handle lids gently without globe pressure. |
| Using a tonometer without checking the cornea, device or technique | Injury, cross-infection, inaccurate IOP and false reassurance may follow. | Confirm indication, competence, device condition, calibration and reprocessing. |
| Confusing examination tools with operative instruments | Many surgical tools are sharp, invasive, sterile and unsafe outside the theatre. | Identify their role; do not practise an invasive manoeuvre on a patient without supervision and authorisation. |
| Assuming old and modern cataract instruments have the same current role | Legacy extraction tools may be mislabelled as routine phaco equipment. | Learn historical context and check the actual local technique and current training resource. |
| Reusing a disposable item or using an incompatible IOL injector | May cause contamination, device failure or damage to an implant. | Follow the manufacturer’s compatibility and single-use instructions. |
| Using epilation as definitive treatment for trichiasis | The underlying lid malposition remains and lashes regrow. | Use only as a temporary measure by a trained clinician and ensure eye-service referral. |
Emergency-care equipment priorities
Emergency clinicians may not have a full ophthalmic set. The minimum safe approach is still structured: visual acuity testing, pen torch, appropriate magnification if available, hand hygiene, a rigid eye shield and urgent ophthalmology access. For a suspected open globe, avoid tonometry, ocular ultrasound with pressure, lid eversion, foreign-body removal and any pressure on the eye. Shield without compression and transfer urgently according to local protocol. For chemical injury, immediate irrigation takes priority over obtaining specialised diagnostic equipment. For a contact lens or corneal abrasion case, a slit lamp and fluorescein may be needed, but do not delay urgent care for a vision-threatening presentation.
Equipment readiness should include a clear referral telephone pathway, means to document and communicate visual acuity, safe transport arrangements and a functioning source of light. Red flags include sudden visual loss, penetrating trauma, chemical exposure, a corneal opacity or ulcer, severe pain with photophobia, an afferent pupil defect, acute angle-closure features, proptosis with restricted movement, and postoperative deterioration.
Clinical and practical cases
Case 1: reduced distance acuity
A patient reads fewer lines with the right eye than the left. The room is bright but the chart is positioned at an unmeasured distance.
Discussion: the first result is not reliably standardised. Establish the correct chart distance and lighting, test each eye separately with an occluder, record current correction and repeat. If the result remains reduced, use pinhole if appropriate and continue clinical assessment; do not stop at “refractive error.”
Case 2: painful red eye with possible foreign body
A patient reports pain and tearing after metal work. The clinic has a pen torch and magnifying loupe but no slit lamp.
Discussion: record visual acuity, ask about high-velocity injury and assess for red flags. Do not blindly sweep or press on the globe. Suspected penetrating injury needs a rigid shield and urgent referral. A superficial foreign body should be assessed and managed only by a clinician with the required equipment and competence.
Case 3: tonometry and a damaged prism
Before applanation tonometry, a trainee sees a crack at the edge of a reusable prism.
Discussion: do not use it. A damaged prism may injure the cornea and can be difficult to reprocess. Remove it from service and use a safe, properly processed alternative or arrange measurement through the eye unit.
Case 4: identifying a hook
At a practical examination, a blunt guarded hook and a curved knobbed hook are displayed together.
Discussion: compare tip guard and handle plane. The guarded strabismus hook is designed to engage extraocular muscle; the lens expressor is associated with older lens delivery techniques. Similar silhouette does not mean identical use.
Revision questions
- Name four items in a basic primary eye-care kit and state one role for each.
- What does a pinhole result suggest, and what can it not exclude?
- Which instrument provides stereoscopic magnified anterior-segment examination?
- Name three instruments or tests used to assess IOP, angle or optic nerve in glaucoma evaluation.
- What is the role of a side-port blade compared with a keratome?
- Which instrument is associated with phaco nucleus chopping?
- What does a Simcoe cannula do, and in which approach is it classically used?
- How do enucleation and evisceration differ?
- Which instruments in the deck relate to lacrimal surgery?
- Why is the lens expressor a legacy-associated instrument in many settings?
- What should be done if a tonometer prism is cracked?
- What is the immediate equipment response to suspected open-globe injury?
Answers and explanations
- Examples: distance chart for acuity; torch for pupils/gross inspection; loupe for magnification; shield for no-pressure protection; epilation forceps for trained temporary lash removal.
- Improvement suggests an optical/refractive component. It does not rule out ocular disease, retinal or optic-nerve pathology, or the need for full examination.
- The slit-lamp biomicroscope.
- Goldmann or another appropriate tonometer, gonioscopy lens for angle examination, and ophthalmoscopy or imaging for optic-nerve assessment; visual-field testing assesses functional loss.
- The side-port blade creates a smaller accessory entry; a keratome creates a larger planned corneal entry in a compatible surgical technique.
- The chopper, used with the phaco handpiece by a trained surgeon.
- It irrigates and aspirates lens material, classically during manual extracapsular cataract extraction; contemporary systems may automate these functions.
- Enucleation removes the entire globe; evisceration removes intraocular contents while retaining the scleral shell.
- Bowman probes, bone punch, lacrimal sac dissector/curette and Müller lacrimal wound retractor.
- Its classic uses relate to intracapsular or extracapsular lens delivery, techniques less common where modern phacoemulsification is available.
- Do not use it; remove it from service and follow the manufacturer’s and facility’s inspection, replacement and reprocessing policy.
- Place a rigid shield without pressure, avoid further manipulation and arrange urgent ophthalmology transfer under local protocol.
Key terms
| Term | Meaning |
|---|---|
| Applanation | Flattening a defined area of the cornea to estimate IOP. |
| Biomicroscope | Microscope used with focused illumination to examine ocular structures stereoscopically. |
| Condensing lens | Positive lens used with indirect ophthalmoscopy or slit lamp to form a fundus image. |
| Capsulorhexis | Controlled opening made in the anterior lens capsule during cataract surgery. |
| DCR | Dacryocystorhinostomy, a procedure that creates a drainage pathway between lacrimal sac and nose. |
| ECCE | Extracapsular cataract extraction, an approach that removes the cataract while retaining the posterior capsule. |
| IOL | Intraocular lens implanted after cataract removal. |
| IOP | Intraocular pressure. |
| Phacoemulsification | Ultrasound-assisted cataract removal through a small incision using a phaco handpiece. |
| Reprocessing | Validated cleaning, disinfection and/or sterilisation steps required to prepare a reusable device for safe reuse. |
Related ophthalmology lessons
- Tarsal plate rotation for trichiasis: indications, technique and aftercare
- Enucleation: indications, procedure, complications and socket care
- Glaucoma surgery: types, indications, procedures and complications
References and further reading
- Scaria T. Ophthalmology instruments ophthalmology PPT. SlideShare, 37 slides. Instrument recognition source supplied for this lesson; uploaded 2014.
- World Health Organization. Medical supplies and equipment for primary health care. Primary eye-care equipment model list.
- World Health Organization. Package of Eye Care Interventions. 2022. Service-level eye-care interventions and resource considerations.
- World Health Organization Regional Office for Africa. Primary Eye Care Training Manual. 2018.
- American Academy of Ophthalmology EyeWiki. Slit Lamp Examination.
- American Academy of Ophthalmology EyeWiki. IOP and Tonometry.
- College of Optometrists. Equipment list for the routine eye examination.
- Community Eye Health Journal. Ophthalmic instruments and equipment: their care and maintenance.
Student takeaway: begin with the right equipment for the service level: measure vision carefully, inspect with appropriate illumination and magnification, and refer when the clinical question exceeds local capability. In the theatre set, identify an instrument by its tip and working shape, connect it to the tissue and operation, and know whether its role is current or historical. Keep every device clean, functional, calibrated when relevant and within the operator’s competence.
