8.1 Cataract surgery preparation & sterile technique

The Sterile Field: Foundation of Ophthalmic Surgery

Every cataract operation depends on an uncompromising barrier between microorganisms and the interior of the eye. The technician who assists in surgery must understand not only what to do but why each step guards against endophthalmitis, the sight-threatening intraocular infection that surgical asepsis exists to prevent.

Surgical Asepsis vs. Medical Asepsis

The COT exam expects a clear distinction between two levels of cleanliness:

• Medical asepsis (clean technique) reduces the number of microorganisms and limits their spread. Handwashing, wearing gloves for routine patient contact, and wiping down an exam chair are medical asepsis. It makes an area clean, not sterile.
• Surgical asepsis (sterile technique) removes all microorganisms, including bacterial spores. It governs the operating field, the instrument tray, and anything that will enter or touch the surgical wound.

The governing rule is simple: once an item is sterile, it stays sterile only by contacting other sterile items. A sterile glove that brushes a non-sterile lamp handle is contaminated instantly, and the whole field must be treated as compromised.

Rules of the Sterile Field

Memorize these principles; they generate many exam questions:

1. Only the top surface of a draped table is sterile; anything below table level is non-sterile.
2. Gowns are sterile from mid-chest to waist in front and from the cuff to two inches above the elbow.
3. Sterile personnel keep their hands above waist level and in front of the body, and never turn their backs on the field.
4. A one-inch margin at the edge of any sterile drape or wrapper is considered non-sterile.
5. Moisture wicks bacteria upward, so a wet drape ("strike-through") is contaminated.
6. When in doubt about sterility, consider the item non-sterile and replace it.

Scrubbing, Gowning, and Gloving

The surgical hand scrub removes transient flora and reduces resident flora using an antiseptic such as chlorhexidine gluconate or a povidone-iodine surgical scrub. Hands are held higher than the elbows so water runs from the cleanest area (the fingertips) toward the elbows. After scrubbing, the surgeon dries with a sterile towel, dons the sterile gown, and gloves using closed gloving, in which the hands stay inside the gown cuffs until they are inside the gloves. This keeps bare skin from ever touching the outside of the glove.

Attire and Operating-Room Traffic

Everyone in the operating room wears clean surgical attire, a mask covering the nose and mouth, and a cap that contains all hair; these limit the shedding of skin and respiratory organisms toward the field. Personnel are divided into sterile and non-sterile roles, and the two keep a safe margin from each other: a non-sterile circulator faces the sterile field and never reaches across it, while sterile team members pass one another back-to-back. Traffic through the room is minimized and doors kept closed, because air currents carry particles and each opening disrupts the room's controlled airflow.

Preparing and Draping the Surgical Eye

Povidone-Iodine Prep

Preoperative 5% povidone-iodine applied to the ocular surface and conjunctival cul-de-sac is the single most evidence-based measure for lowering endophthalmitis risk. A 10% povidone-iodine solution is used to prep the periocular skin and lids, painted in expanding circles that move from the lash margin outward. Adequate contact time (commonly cited as about three minutes) is needed for antisepsis. A true iodine allergy is uncommon; when it is confirmed, dilute aqueous chlorhexidine or another agent may be substituted per protocol.

Draping

The sterile drape isolates the surgical eye and creates a continuous sterile surface from the patient to the instrument tray. An adhesive plastic drape is pressed over the lashes and lid margins, and the lashes are folded away from the wound so they cannot contact instruments. A lid speculum then holds the lids open. Proper draping keeps the eyelashes and meibomian glands, which are heavy sources of bacteria, out of the surgical field.

The Surgical Time-Out and Site Verification

Before the first incision the team performs a time-out, a mandatory pause (the Joint Commission Universal Protocol) in which all activity stops and members verbally confirm:

• Correct patient identity (two identifiers)
• Correct procedure
• Correct site and side — critical in ophthalmology, where operating on the wrong eye is a "never event"
• Correct intraocular lens and its power
• Availability of any special equipment

The correct eye is typically marked before the patient enters the room, and the mark should remain visible after draping. The technician often participates by reading the chart, confirming the IOL, and documenting the time-out.

Cataract / Phacoemulsification Workflow

At a high level, modern small-incision cataract surgery proceeds in this order:

1. Anesthesia — usually topical drops with intracameral lidocaine; sometimes a regional block.
2. Incision — a self-sealing clear-corneal incision with a keratome, plus a paracentesis.
3. Viscoelastic (OVD) — injected to maintain the anterior chamber and protect the corneal endothelium.
4. Capsulorhexis — a continuous circular tear in the anterior capsule.
5. Hydrodissection — fluid separates the nucleus from the capsule.
6. Phacoemulsification — an ultrasonic handpiece fragments and aspirates the lens nucleus.
7. Irrigation/aspiration (I/A) — removes residual cortex.
8. IOL insertion — the folded lens is injected into the capsular bag.
9. Wound hydration and closure — the self-sealing incision is checked; a suture is rarely needed.

The Technician's Role

The assisting technician maintains the sterile field, anticipates and passes instruments, manages irrigation fluids and viscoelastic, monitors the phaco console settings, verifies the IOL, documents the case, and watches the patient's comfort and cooperation. Vigilance in protecting sterility and confirming the correct site is the technician's single most important contribution to a safe outcome.