Table 2:

(A) Ocular complications in non-ocular surgery, risk factors, prevention, and treatment. (B) Commonly encountered ocular conditions, pre- and intra-operative concerns, what is known/not known in relation to anesthesia, and management recommendations. See text for more details and references. Due to space constraints, not all conditions are shown.

A	Exposure keratopathy	Loss of eye contents	Acute angle closure glaucoma	Ischemic optic neuropathy	Central retinal artery occlusion
Risk Factors	*General anesthesia *Decreased tear production *Patient positioning *Abnormal eyelid closure	*Corneal transplant *Open globe injury	*History of glaucoma *Genetics *Female *Elderly *Anatomical factors *Asian race	*Spine fusion *Cardiac surgery *Head and neck *For spine surgery: Prone positioning, large estimated blood losses, lower colloid compared to crystalloid fluid administration, lengthier anesthesia duration, Wilson frame use, obesity, and male sex	*Spine fusion *Cardiac surgery *Head and neck *Use of N2O with recent vitrectomy and gas bubble *For spine surgery: compression of the eye *For cardiac surgery: emoblism from heart or aorta
Prevention	*Completely cover the eyes after induction of anesthesia *Use of ointments in some cases *Remove contact lenses *Protect eye from false eyelashes	*Protect eyes from trauma/increased IOP *Eye shield, caution during positioning of patient	*Medications to avoid in susceptible individuals (see text): para-sympatholytic or sympathomimetic drugs	No established strategy but see text for ASA Task Force on Perioperative Visual Loss recommendations	*Headrests and care to prevent eye compression in spine surgery with patient prone *Decrease embolic phenomena in heart surgery *Avoid N2O when vitreous gas bubble present (see text)
Treatment	*Analgesia (local anesthetic eye drops not advisable) *Antibiotics/eye cover in some cases *Treatment/followup by an ophthalmologist	*None. Prevention is paramount to avoid profound visual loss	* Immediate reduction of IOP by medications AND *Peripheral iridectomy *Treatment/followup by an ophthalmologist	*Increase blood pressure and hemoglobin levels *Elevate the head *Steroids *Hyperbaric oxygen None of these are proven effective. In all cases, consultation on treatment with neuro-ophthalmologist	*Thrombolysis, but may be risky in post-operative patient. *Consultation on treatment with neuro-ophthalmologist

B	Idiopathic intracranial hypertension	Glaucoma	Low vision
Pre-op eye concerns	*Optic nerve disease: double vision, loss of vision, optic nerve swelling	*Visual field loss, low vision, increased intraocular pressure	*Difficulty with consent *Communication issues *Altered mood, alertness
Intra-operative concerns	*Spinal and epidural analgesia *Caution in COPD patients on acetazolamide	*Head down or prone positioning and visual outcomes	*None
What is known	*Both spinal and epidural may be used safely *Continue pre-operative medications for the disease	*Intraocular pressure increased by positioning prone or head down	*Many causes including glaucoma, diabetic retinopathy, macular degeneration, congenital
What is not known/Perioperative management recommendations		*Impact of further increases in intraocular pressure on vision after surgery/positioning prone or head down is not known *Advisable to keep systemic blood pressure at or near patient’s baseline, as systemic blood pressure is a major influence on ocular perfusion pressure; evidence base still lacking. *Continue the patient’s pre-operative eye drops up until time of surgery	*The impact of low vision with or without altered alertness on awakening after anesthesia is not known. *Anticipate the need for more time to obtain a pre-operative anesthesia consent.

Abbreviations: ASA = American Society of Anesthesiologists. COPD = chronic obstructive pulmonary disease. IOP = intraocular pressure. N2O = nitrous oxide