Eye injuries during general anaesthesia
Eye care during general anaesthesia is an important part of anaesthesia care. Eye injuries are reasonably common if care is not taken to prevent them.
Incidence of eye injuries
The incidence of eye injuries during general anaesthesia has been studied, and different methods of eye protection have been compared.
Effect of general anaesthesia on eyes
In addition, general anaesthesia reduces tear production and tear-film stability, resulting in corneal epithelial drying and reduced lysosomal protection. The protection afforded by Bell's phenomenon (in which the eyeball turns upwards during sleep, protecting the cornea) is also lost during general anaesthesia. 
Mechanism of Injury
An open eye increases the vulnerability of the cornea to direct trauma from objects such as face masks, laryngoscopes, identification badges, stethoscopes, surgical instruments, anaesthetic circuits, and drapes. 
Exposure keratopathy/keratitis refers to the drying of the cornea with subsequent epithelial breakdown.  When the cornea dries out it may stick to the eyelid and cause an abrasion when the eye reopens. 
Chemical injury can occur if cleaning solutions such as povidone-iodine (Betadine), chlorhexidine or alcohol are inadvertently spilt into the eye, for example when the face, neck or shoulder is being prepped for surgery.  
Therefore, the anaesthetist ensures that the eyes are fully closed and remain closed throughout the procedure. Seemingly trivial contact can result in corneal abrasions and the risk of this occurring is markedly increased if exposure keratopathy is already present.  Corneal abrasions can be excruciatingly painful in the postoperative period, may hamper postoperative rehabilitation and may require ongoing ophthalmological review and after care. In extreme cases there may be partial or complete visual loss.
Iatrogenic injury of the eyelids is also common. Bruising (frequently) and tearing (rarely) of the eyelid can occur when the adhesive dressing used to hold the eye closed is removed. Removal of eyelashes can also occur.
Methods available for eye injury prevention
Methods to prevent intraoperative corneal injuries include
- simple manual closure of the eyelids
- holding the eyelids shut with tape or a general purpose adhesive dressing
- use of a specially designed eyelid occlusion dressing
- use of eye ointment (although this is controversial, see below)
- bio-occlusive dressings
- suture tarsorrhaphy
However, none of the protective strategies are completely effective; vigilance is always required i.e. the eyes need to be inspected regularly throughout surgery to check they are closed.
Discussion of methods
The most commonly employed method is to use tape or a general purpose adhesive dressing. Unfortunately the adhesive used on the tape or dressing will generally be inappropriate for this use. The adhesive strength may change when reaching body temperature, or over time.
As the operation progresses this can cause the adhesive to stop working and become gooey, allowing the eyelids to move apart, and leaving behind a sticky residue. This leaves the cornea exposed to epithelial drying and/or abrasions, sometimes caused by the tape that was originally applied to protect the cornea. Alternatively, the adhesive strength may increase, which upon removal can result in eyelid bruising, tears, or eyelash removal.
Rolls of tapes are often “laying around” the operating theatre or kept in health care workers' pockets.
Therefore they can be a source of hospital-acquired infections (HAI's) such as Methicillin-resistant Staphylococcus aureus (MRSA) & Vancomycin-resistant Enterococcus (VRE), with a 2010 study showing that 50% of partially used tape rolls tested positive for MRSA, VRE or both.
Most tapes and dressings are non-transparent and so it is not possible to see if the patient’s eyes are opened or closed throughout the case. It is not uncommon for the eyelids to move open as the case progresses, even with adhesive tapes stuck onto them. In a practical sense, these medical tapes/dressings may be difficult to remove from a patient because their ends can become stuck flush with the skin. The possibility of tape removal causing trauma is also significantly increased in older people, people with sensitive skin, dermatitis, dehydration or side effects of medications.
As noted above, there have been several studies looking at the efficacy and safety of eye ointments/lubricants as adjuncts with tape or as a stand-alone management for intra-operative eye closure. Unfortunately many in common use have problems. Petroleum gel is flammable and is best avoided when electrocautery and open oxygen are to be used around the face. Preservative-free eye ointment is preferred, as preservative can cause corneal epithelial sloughing and conjunctival hyperemia. They have been implicated in blurred vision in up to 75% of patients and they do not protect from direct trauma.
Specially made eyelid occlusion dressings are available commercially, such as EyeProTM (Andsco Medical Pty Ltd, Australia), EyeGardTM (KMI Surgical) and Anesthesia-Aid (Sperian Protection). These dressings overcome most of the problems associated with tape or general purpose dressings.
The EyePro is shaped to conform to the eye socket, has a transparent centre for monitoring of the eye throughout the procedure, and has non-stick tabs on both sides of the eye for application and removal.
The EyePro allows for the eye to be completely sealed for protection from outside harm, as well as moisture maintenance without the need for drops or ointments. The adhesive has been carefully selected to provide adequate security while still avoiding eyelid bruising and tears. It is also supplied sterile to address the HAI risk posed by tape.
The EyeGard is a transparent, non-sterile, hypoallergenic barrier to cover the eye during anaesthesia. It is oval shaped to fit the shape of the eye and has a single non-adhesive tap for ease of removal.
The Anesthesia-Aid is an oval shaped dressing with adhesive around the edges only to fit around the eye. It has a single tab for easy application and removal.
Adverse outcomes associated with intra-operative eye injuries
Some of the adverse outcomes associated with intra-operative injuries include:
- Increased length of stay. This is due to ophthalmology consults required, associated infections and treatment.
- Increased costs. This is due to increased length of stay, cost of treating the complications.
- Pain and discomfort for the patient. Corneal abrasions are extremely painful for the patient and the treatment consists of drops and ointments applied in the eye which may cause further discomfort for the patient.
- S Contractor & JG Hardman 2006, 'Injury During Anaesthesia', Continuing Education in Anaesthesia, Critical Care & Pain, vol. 6, no. 2, pp. 67-70, "Read Article"
- VK Grover, KV Kumar, S Sharma & SP Grewal 1998, 'Comparison of Methods of Eye Protection under General Anaesthesia', Canadian Journal of Anaesthesia, vol. 45, no. 6, pp. 575-7, "Read Article"
- C Marcucci, NA Cohen, DG Metro & JR Kirsch 2008, Avoiding Common Anesthesia Errors, Lippincott Williams & Wilkins, Philadelphia PA USA.
- Kocaturk, O, Kocaturk, T, Kaan, N & Dayanir V 2012 'The Comparison of Four Different Methods of Perioperative Eye Protection under General Anesthesia in Prone Position', Journal of Clinical and Analytical Medicine, vol. 3, no. 2, pp. 163-5 "Read Article"
- J Anson, 'Perioperative Corneal Abrasions: Etiology, Prevention, and Management', Pennsylvania Society of Anesthesiologists, "Read Article".
- PN Nair & E White 2014, 'Care of the Eye During Anaesthesia and Intensive Care', Anaesthesia and Intensive Care Medicine, vol. 15, no. 1, pp. 40-43, "Read Article".
- E White 2004, 'Care of the eye during anaesthesia', Anaesthesia and Intensive Care Medicine, vol. 5, pp. 302-3 "Read Article".
- K Zheng, CG Guta, V Kulkarni & J Brock-Utne 2009, 'Prevention of Corneal Abrasions in Patients with Autoimmune Dry Eyes', Anaesthesia and Analgesia, vol. 108, no. 1, pp. 385-6, "Read Article"
- A Grixti, M Sadri & MT Watts 2013, 'Corneal Protection during General Anesthesia for Nonocular Surgery', The Ocular Surface, vol. 11, no. 2, pp. 109-18, "Read Article"
- NJ Friedman & PK Kaiser 2007, Essentials of Ophthalmology, Elsevier Health Sciences, Philadelphia PA USA.
- N Tarmey & LA White 2009, 'Section 5: Damage to the eye during General Anaesthesia', Risk Associated with your Anaesthetic, Royal College of Anaesthetists website, "Read Article".
- AN Gent 1996, 'Adhesion and strength of viscoelastic solids. Is there a relationship between adhesion and bulk properties?', Langmuir, vol. 12, no. 19, pp. 4492-96, "Read Article".
- Clinical and Laboratory Standards Institute 2010, 'Performance Standards for Antimicrobial Susceptibility testing: Twentieth Informational Supplement', CLSI Document M100-S20"Read Article".
- C Konya, H Sanada, J Sugama, M Okuwa, Y Kamatani, G Nakagami & K Sakaki 2010, 'Skin Injuries Caused by Medical Adhesive Tape in Older People and Associated Factors', Journal of Clinical Nursing, vol. 19, no. 9-10, pp. 1236-1242 "Read Article".
- M Weed & N Syed 2012, 'Perioperative Corneal Abrasions: Systems-based review and analysis', EyeRounds.org, "Read Article".
- Andsco Medical Pty Ltd, "EyePro", Andsco Medical
- KMI Surgical, "EyeGard", KMI Surgical
- Sperian Protection, "Anesthesia-Aid", Sperian Protection
- S Prakash 2013, 'Perioperative Eye Protection under General Anaesthesia', Journal of Anaesthesiology Clinical Pharmacology, vol. 29, no. 1, pp. 138-139 "Read Article".