2. Contents
• Revision on ocular anatomy and physiology
• Effect ophthalmic drugs on anesthesia management
• Preoperative evaluation for ophthalmic surgical patients
• Oculo-cardiac reflex (OCR) and anesthesia
• Regional anesthesia for ophthalmic surgical patients
• Anesthesia management for glaucoma (trabeluectomy) surgery
3. Learning Objectives
• Discuss the anatomy and physiology of the eye
• Discuss about OCR and effect on anesthetic management
• Describe the effects of ophthalmic drugs on anesthesia management
• Assess and optimize Ophthalmic surgical patients
• Perform regional anesthesia block for various types of eye procedure
• Provide and manage anesthesia for various types of Ophthalmic
surgical patients
4. Introduction
• Ophthalmic surgery can be performed under either general or
regional anesthesia.
• Basic knowledge of the anatomy of the orbit & its contents is
necessary for the successful performance of regional anesthesia for
ophthalmic surgery.
• Knowing ocular physiology is important in the management of
raised intraocular pressure & for the general care of the eye.
5. Introduction conti…
• Except few, most of ophthalmic procedures have the same anesthetic
consideration.
• Some of ophthalmic drugs given perioperatively can react with
anesthetics & result in complications.
• Knowledge & skill of pediatric & geriatric anesthesia necessary to
ophthalmic surgery.
6. Anatomy of the eye
Orbit and Eyeball
• The eyeball is safely lodged in a bony socket called the orbit on the
two sides of the nose.
Each orbit is in the shape of an irregular pyramid with its
Base at the front of the skull
Axis pointing posteromedially towards the apex
7. Anatomy conti…
• The orbit composed of four walls.
The four walls are called the:
• Roof
• Floor
• Medial and
• Lateral walls.
9. Anatomy conti…
• The roof has two bones:
1. The frontal and
2. Greater wings of sphenoid bone.
The floor has three bones:
1. Orbital plate of maxilla,
2. Orbital surface of zygomatic, and
3. Orbital process of palatine bone.
10. Anatomy conti…
The strongest lateral wall has two bones:
1. Zygomatic and
2. Sphenoid.
The thinnest medial wall has four bones:
1. Frontal process of Maxilla
2. Lacrimal bone
3. Orbital plate of ethmoid bone, and
4. A small part of body of sphenoid bone
11. Anatomy conti…
• The orbit measures 40-50mm deep with a volume of approximately
30ml.
• 7ml of the orbit is occupied by the globe and its muscular cone with
the remainder composed of loose connective tissue.
• The orbit contains the globe, orbital fat , extraocular muscles,
nerves, blood vessels and part of the lacrimal apparatus.
12. Anatomy conti…
• Globe
The wall of the globe is composed of three layers:
1. Sclera
2. Uveal tract, and
3. Retina
The middle layer is the uveal tract. It is composed of three specialized
structures:
1. Iris
2. Ciliary body located in the anterior uvea, and
3. Choroid located in the posterior uvea.
13. Anatomy conti…
The Sclera
Sclera: is opaque and white and covers 80% of the globe.
It is the fibrous layer of the eyeball completely surrounding the
globe except the cornea
It is relatively tough but can be pierced easily by needles
The optic nerve penetrates the sclera posteriorly 1 or 2 mm medial to,
and above, the posterior pole
The central retinal artery and vein accompany the optic nerve
14. Anatomy conti…
Uveal tract
• The uveal tract is the middle layer of the globe.
It is composed of three specialized structures:
• Iris
• Ciliary body located in the anterior uvea, and
• Choroid located in the posterior uvea.
15. Anatomy conti…
Iris
• The iris contains dilator and sphincter muscle fibers that control the
central aperture, the pupil.
• Parasympathetic stimulation originating from the CN III nucleus
contracts iris sphincter fibers, causing pupillary constriction or miosis.
• Conversely, sympathetic fibers traveling with the ophthalmic division
of CN V stimulate iris dilator fibers, dilating the pupil.
16. Anatomy conti…
Ciliary body
The ciliary body had two primary functions:
-Production of aqueous humor and
-Accommodation
• Ciliary body consists of ciliary muscle and ciliary processes.
When the ciliary muscle connected with the suspensory ligaments that
controls the size/ shape of the lens.
Cilliary body are the one that controls the suspensory ligament to
contract or relax for short and long distance vision respectively.
17. Anatomy conti…
• Ciliary muscle provides the formation of aqueous humor.
• The contraction of ciliary muscles also opens space for increased
aqueous drainage.
18. Anatomy conti…
Choroid
• It is a layer of blood vessels and capillaries.
• These vessels nourish the outer portion of the retina, providing oxygen
and nutrients.
• Bleeding from the choroid layer can cause catastrophic intraoperative
expulsive hemorrhage.
19. Anatomy conti…
Retina
Comprised of two cellular layers
Neural layer – consists of photo receptors i.e. light detecting cells of
the retina
Pigmented layer – support the neural layer and connects with choroid
Photoreceptors of the retinal layer convert light into neural signals,
which are processed and carried to the brain via the optic nerve.
20. Anatomy conti…
Orbital fat
The orbital fat is divided into central (retrobulbar, intracone) and
peripheral (peribulbar, pericone) compartments by the cone of the
recti muscles
The central space contains the optic, oculomotor, abducent and
nasociliary nerves
The peripheral space contains the trochlear, lacrimal, frontal and
infraorbital nerves
21. Anatomy conti…
• Extraocular muscles
The combined actions of the four rectus and two oblique muscles on
each eyeball allow elevation, depression, adduction and abduction.
They form what has been termed a “cone” within the orbit, which
contains the optic nerve, ophthalmic artery and vein, oculomotor and
abducens nerves, and ciliary ganglion.
Testing individual muscle function becomes necessary after local
anaesthetic block
To identify the unblocked nerve when some movement is still
present
23. Anatomy conti…
Muscle Innervation Function
Superior rectus III (oculomotor) Elevation
Inferior rectus III (oculomotor) Depression
Medial rectus III (oculomotor) Adduction
Inferior oblique III (oculomotor) Elevation/abduction
Superior oblique IV (trochlear) Depression/adduction
Lateral rectus VI (abducens) Abduction
Extraocular Muscles: Innervation and Function((LR6SO4)3)
24. Anatomy conti…
Chambers
Anterior chamber formed by the cornea
Posterior chamber found in between iris and suspensory ligament
of choroid body
There is aqueous humor found on both chamber formed in posterior
chamber by choroid plexus and goes to Anterior chamber through
pupillary opening to be absorbed by canal of schelemm {scleral
venous sinuses}.
Aqueous humor nourishes and protects the eye
The vitreous humor remains in the posterior chamber
25. Anatomy conti…
• Canal and Fissure
At the apex is the optic foramen, transmitting the optic nerve and
accompanying vessel
The superior and inferior orbital fissures transmitting the other
nerves and the vessels
Optic Canal – transmits optic nerve and ophthalmic artery
26. Anatomy conti…
SOF – Lacrimal N, Frontal N, 4th CN{Trochlear N}, Superior and
Inferior branch of Oculomotor Nerve {CN 3}, ophthalmic branch of
the trigeminal nerve{CN5}, and Abduscent nerve{CN 6}.
• IOF – transmits zygomatic branch of the maxillary nerve{Branch of
trigeminal nerve}, maxillary nerve itself and inferior ophthalmic vein
and some sympathetic nerves.
27. Anatomy conti…
• Nerves
• The cranial nerves innervate ocular structures.
• The optic nerve (CN II) carries the sensory information from the
retina.
• Cranial nerves III, IV, and VI supply the extraocular muscles.
• The facial nerve (CN VII) has five main branches The branches are,
from top to bottom:
• Frontal (or temporal) branch
• Zygomatic branch
28. Anatomy conti…
• Buccal branch
• Marginal mandibular branch
• Cervical branch
The orbicularis oculi muscle, innervated by the zygomatic branch of the
facial nerve, allows the patient to close the eyelid tightly.
29. Anatomy conti…
• Blood vessels
• The blood supply to the ocular structures is primarily the ophthalmic
artery.
• The ophthalmic artery is a branch of the internal carotid artery just
before the circle of Willis.
• Venous drainage flows though the superior and inferior ophthalmic
veins directly to the cavernous sinus.
32. Anatomy conti…
The lacrimal apparatus
• The lacrimal gland is located in a shallow depression within the orbital
portion of the frontal bone.
• Tears are formed here by the serous secretion of acinar and
myoepithelial cells.
• Under both reflex and psychogenic stimulation, tears pass from the
surface of the eye via the puncta, through either the upper or the lower
canaliculi to the lacrimal sac and duct, and drain into the nasopharynx
below the inferior turbinate
33. Physiology of the Eye
Oculomedullary reflexes
I. Oculocardiac reflex
II. Oculorespiratory reflex
III. Oculoemetic reflex
I. Oculocardiac reflex
• The oculocardiac reflex (OCR) is caused by traction on the extraocular
muscles, manipulation of the globe, or increase in IOP.
34. Physiology conti…
• Especially seen with traction of medial rectus muscle, but can occur
in stimulation of any orbital component.
• The reflex is trigeminovagal.
• Afferent limb – orbital contents fibers – ciliary ganglion to opthalmic
of division of the trigeminal nerve – sensory nucleus of trigeminal
nerve near the 4th ventricle.
• The efferent limb is via the vagus nerve to the heart.
35. Physiology conti…
It is most commonly occurring during:
• Eye muscle surgery,
• Retinal detachment repair
• Enucleation, and
• Even been observed following retrobulbar block and retrobulbar
hemorrhage.
• Most commonly encountered in pediatric patients undergoing strabismus
surgery
36. Physiology conti…
Contributing factors for OCR
• Preoperative anxiety
• Light anesthesia
• Hypoxia
• Hypercarbia
• Increased vagal tone owing to age
• Procedures under topical anesthesia
• Orbital infections
37. Physiology conti…
• The OCR is most commonly manifested as bradycardia.
The other clinical presentations of OCR includes:
• Ectopic beats,
• Nodal rhythms
• Atrioventricular block, and
• Asystole.
• It is the vagus innervation to the abdominal viscera that causes nausea
and vomiting that can accompany the cardiac manifestations.
• Evidences reported that 90% of patients experienced OCR during
traction of the extraocular muscles.
38. Physiology conti…
Diagnosis and treatment
• Diagnosis relies upon continuous monitoring of the
electrocardiogram (ECG).
• Bradycardia
• In awake pts, may be accompanied by nausea.
Treatment can be supportive or therapeutic based upon the severity of
the reflex;
What will happen on electrocardiogram (ECG) during OCR?
39. Physiology conti…
• Wide QRS complex =Ventricular arrhythmia
• R –R ,QRS ,PR INTERVAL PROLONGRD,
• Asystol-all are stright’’ no cardiac activity seen
• Ventricular fibrillation-There is chaotic & disorganized contraction of
ventricular muscle and no QRS complexes can be identified on the
ECG
40. Physiology conti…
- If the reflex manifests as bradycardia or infrequent ectopic beats and
the blood pressure remains stable;
- Adequate ventilation with 100% O2.
- Ensure sufficient anesthetic depth.
- If the dysrhythmias become significant;
- Stop surgical stimulation.
41. Physiology conti…
When the OCR is severe, treatment with anticholinergics
(glycopyrrolate or atropine) is indicated.
- atropine, 0.02mg/kg IV is effective for 30 minutes in preventing &
treatment of bradycardia associated with the oculocardiac reflex.
Doses >0.5 Mg IV can cause tachycardia. which can be detrimental
in certain patients with heart disease.
-glycopyrulate, 0.01mg/kg.
• Asystole – chest compression
42. Physiology conti…
II. Oculorespiratory reflex
• Can be manifested as;
- shallow breathing
- reduced respiratory rate
- full respiratory arrest.
• The afferent pathways are similar to OCR, and it is thought that a
connection exists between the trigeminal sensory nucleus and the
pneumotactic center in the pons and medullary respiratory center.
• Common in strabismus surgery and atropine has no effect.
• Airway maintenance by controlled ventilation
43. Physiology conti…
III. Oculoemetic reflex
• Responsible for the high incidence of vomiting after squint surgery
(60-90%).
• Trigemino-vagal reflex with traction on the extraocular muscles
stimulating the afferent arc.
• Antiemetics may reduce the incidence & a regional block technique
provides the best prophylaxis.
• Dexamethasone, Metoclopramide, Promethazine, scopolamine
44. Physiology conti…
Intraocular pressure
• IOP is the pressure exerted by the contents of the eye upon the cornea
and sclera of the globe.
• The blood supply to the retina and optic nerve depends on the
intraocular perfusion pressure (IOPP).
• OPP = MAP- IOP
• High IOP impairs the blood supply, leading to a loss of optic nerve
function.
45. Physiology conti…
• After an incision in the globe is made, factors that would increase IOP
can cause prolapse and loss of intraocular contents; this can cause
permanent vision loss.
• The volume of the globe is principally determined by the aqueous
humor and the blood vessels of the eye, particularly of the choroid.
• Aqueous humor volume is determined by the production and drainage
of aqueous.
46. Physiology conti…
• Normal IOP is 10-20 mm Hg in the sitting position and is generally
maintained within this narrow range.
IOP undergoes normal minor fluctuations because of
1. Changes in body position (+1 mm Hg supine),
2. Diurnal rhythm (2–3 mm Hg),
3. Blood pressure oscillations (1–2 mm Hg), and
4. Respiration (deep inspiration decreases IOP by 5 mm Hg).
5. Changes in blood pressure are reflected in IOP:
47. Physiology conti…
Other factors that will increase IOP includes:
• Any straining,
• Bucking,
• Breath holding,
• Obstructed airway
• Valsalva maneuvers,
• Endotracheal intubation
• External pressure from face mask, fingers, orbital tumors, contraction
of the orbicularis oculi muscle, or retrobulbar hemorrhage.
48. Physiology conti…
• The globe is relatively non-complaint compartment
• The volume of internal structure is fixed except
Aqueous fluid
Choroidal blood volume
The quantity of this factor regulates IOP
49. Physiology conti…
Implication of aqueous humour dynamic:
Compensation is by an increased rate of aqueous humour
drainage
Aqueous humour production is largely constant
Therefore, the normal regulation of IOP:
Production of aqueous humour
Resistance to aqueous outflow
Episcleral venous outflow
50. Physiology conti…
• 2/3 of the aqueous fluid is actively secreted by the ciliary body by a
sodium pump mechanism
• 1/3 comes from passive filtration through vessels on the iris
• Aqueous fluid is produced at a rate of 2ul/min
52. Physiology conti…
• Aqueous flow over the lens and through the pupil to bath the inner
corneal endothelium
• It then enter the angle of the anterior chamber to flow through to
trabecular meshwork to the canal of Schlemm
• The canal of Schlemm continuous to the episcleral vein
54. Physiology conti…
• Sclerosis of the trabecular meshwork is believed to cause the chronic
pressure elevation in open angle glaucoma
• Closed angle glaucoma occurs when there is an obstruction to aqueous
drainage from the anterior chamber angle
• This happens from peripheral iris swelling or anterior displacement
• Patients with preexisting narrow angle may be predisposed to this
condition
• The acute increase in pressure causes severe pain – ophthalmologic
emergency
55. Physiology conti…
Choroidal blood volume & IOP
• Changes in choroidal blood volume can increase IOP rapidly
• Hypercapnia causes choroidal congestion
• Coughing, straining or vomiting can increase IOP to 30 to 40 mmHg
• Endotracheal intubation can cause similar increase
56. Physiology conti…
• The increases are transient and are relatively not harmful in a closed
eye
• In an open eye, such as after traumatic injury or during cataract
surgery, these increase can lead to
• loss of intraocular contents, hemorrhage, and permanent vision loss
57. Physiology conti…
Extrinsic compression & IOP
• External compression increases IOP
• A normal blink increases IOP by 10mmHg
• A force full lid squeeze can increase IOP to > 50mmHg
• A poorly placed anesthesia mask can put enough pressure on the eye to
reduce blood flow to zero.
58. Physiology conti…
Anesthesia & IOP
• Deep IAA and thiopental anesthesia causes a dose related reduction in
IOP by 30 -40%
• Opioids have no /little effect
• Atropine in the usual dose doses does not cause a significant increase
in IOP, even in patients with open-angle glaucoma.
59. Physiology conti…
• Ketamine may cause a modest increase in IOP
• Intravenous sux causes IOP to increase by 6 – 12mmHg
• This last for 5 – 10min
• The use sux for induction in case of open angle injury with full
stomach has been controversial
• Loss of vitreous in pts from sux has not been reported
61. Physiology conti…
Action of anesthetic drugs on eye - MoA
• The exact mechanisms are unknown
• Postulated causes include
• Depression of a central nervous system (CNS) control center in the
diencephalon,
• Reduction of aqueous humor production,
• Enhancement of aqueous humor outflow, or
• Relaxation of the Extraocular muscles
62. Physiology conti…
• The depolarizing drug elevates IOP
• Mechanisms
• Tonic contraction of extraocular muscles,
• Choroidal vascular dilation and
• Relaxation of orbital smooth muscle
• Regional anesthesia:
• Several ml of LA into the orbit
• Peri-bulbar anesthesia may increase IOP
• A reduction in IOP following sub-Tenon blocks
63. Physiology conti…
• Management of raised IOP
• It can be:
• Avoiding a raised IOP
• Pharmacological treatment
1. Avoiding a raised IOP
• Avoid a raised CVP by:
• Use reverse Trendelenberg position
• Avoidance of venous congestion, i.e
• neck positioning or tube ties around the neck
64. Physiology conti…
• Avoid Coughing, straining, and vomiting
• Avoid Laryngoscopy and intubation if possible
• Avoid Inadvertent external pressure
• Controlled blood pressure
• Hyperventilation
66. Effect ophthalmic drugs on anesthesia management
• Some ophthalmic medications given in the perioperative period are
sufficiently potent to have systemic effects.
Phenylephrine
• Phenylephrine is commonly used as a mydriatic.
• There is little increase in mydriasis when solutions with concentrations
>5% are used.
• This response is important because significant complications have
been reported with 10% phenylephrine.
68. Ophthalmic drugs conti…
Epinephrine
• Topical application of 2% epinephrine solution to the eye causes a decrease in aqueous
secretion and improves outflow, both of which act to reduce IOP in open-angle glaucoma.
Complications include:
• Hypertension,
• Tachycardia,
• Dysrhythmias, and
• Fainting
69. Ophthalmic drugs conti…
• Because a single drop of 2% solution contains 0.5–1.0 mg of
epinephrine, it is reasonable to expect systemic complications to occur
• Intraocular epinephrine administered during halothane anesthesia is
poorly absorbed and has no significant cardiac effects.
70. Ophthalmic drugs conti…
β-Adrenergic antagonists
• β-Adrenergic antagonists (e.g., timolol) are used in the treatment of
glaucoma. This class of medication acts to reduce aqueous humor secretion,
with minimal effects on aqueous outflow.
• Excessive dosage of β-adrenergic antagonists may lead to cardiovascular
dysfunction, including bradycardia, palpitations, syncope, bronchospasm
,increase in heart block, and congestive heart failure.
71. Ophthalmic drugs conti…
Echothiophate iodide
• It is a long-acting anticholinesterase drug still used to treat glaucoma.
The pupil is constricted and aqueous drainage is increased. Its duration
of action is 4–6 weeks.
• If a patient receives succinylcholine, a relative overdose of
succinylcholine leads to 2–3 times the usual duration of action.
• The effects of ester local anesthetics may be significantly prolonged
72. Ophthalmic drugs conti…
Muscarinic agonists
• They are given to cause prolonged mydriasis.
• A drop of atropine 1% solution contains 0.2–0.5 mg of the drug.
• One drop of 0.5% scopolamine contains 0.2 mg of the drug.
• Systemic reactions are manifest by tachycardia, flushing, thirst, and dry skin.
• Elderly patients may show agitation.
• It is contraindicated in closed-angle glaucoma. b/c of mydriatic effect w/h
obstracts the aqueous humor outflow.
73. Ophthalmic drugs conti…
Acetazolamide
• It is a Carbonic anhydrase inhibitor interferes with the formation of
aqueous humor and lowers IOP.
The side effects of the medication includes:
• Depletion of sodium and potassium,
• Dyspepsia.
• Decrease in blood pressure.
74. Preoperative evaluation for ophthalmic surgical
patients
• Patients coming to the operating room for ophthalmologic surgery
tend to be extremely young, very old, or have comorbid conditions.
• Infants often present with
• Apnea,
• Respiratory distress ( bronchopulmonary dysplasia),
• Patent ductus arteriosus, or
• Persistent pulmonary hypertension.
75. Preoperative conti…
The elderly present with:
• Coronary artery disease,
• Atherosclerosis,
• hypertension,
• Vascular heart disease,
• Chronic obstructive pulmonary disease,
• Type 1 or type 2 diabetes,
• Cerebrovascular disease, dementia, Parkinson disease, renal or hepatic
disease, arthritis, osteoporosis, or cancer.
76. Preoperative conti…
A preoperative visit should be conducted to
• Allay anxiety,
• Explain the anesthesia plan, and
• Educate the patient regarding medications to be continued on the day
of surgery (β-blockers, antihypertensives, insulin therapy) and
medications that may be of value to discontinue (antiplatelet agents
and other anticoagulants).
77. Preoperative conti…
• Most ophthalmologic procedures are of low risk because there are no
major physiologic derangements, blood loss, or fluid shifts.
• Most of the risk to the eye associated with anesthesia relates to patient
movement, changes in IOP, and postoperative nausea and vomiting
(PONV).
• PONV?
78. Preoperative conti…
• For patients undergoing prolonged procedures assessment of
metabolic equivalents is very important.
• Inability to achieve 4 METS might be indicative of significant
coronary artery disease or congestive heart failure and left ventricular
dysfunction.
79. Preoperative conti…
The requirements of ophthalmic surgery include:
• Safety,
• Akinesia,
• Analgesia,
• Minimal bleeding,
• Avoidance or obtundation of the oculocardiac reflex,
• Prevention of intraocular hypertension,
• Awareness of drug interactions, and
• A smooth emergence devoid of vomiting, coughing, or retching
80. Preoperative conti…
A number of anesthetic options exist, including
• General anesthesia
• Regional anesthesia
• Topical anesthesia
• Monitored anesthesia care(MAC)
81. Preoperative conti…
The choice of anesthesia technique should be individualized on the basis
of:
• The patient’s needs and preferences,
• The nature and duration of the procedure, and
• The preferences and skills of the anesthesiologist and the surgeon.
Sedation in ophthalmic surgery?
83. Glaucoma conti…
Open Angle Glaucoma
• The angle refers to the space between the iris and the cornea in the anterior
chamber, which can become structurally obstructed.
• In open angle glaucoma, there is characteristic optic nerve damage and loss
of visual function in the presence of an open angle with no identifying
pathology.
• Although elevated IOP is often associated with the disease, elevated IOP is
not necessary to make the diagnosis.
84. Glaucoma conti…
Risk factors for the disease include
• Elevated intraocular pressure,
• Increasing age,
• Positive family history,
• Racial background,
• Myopia,
• Thin corneas,
• Hypertension, and
• Diabetes
85. Glaucoma conti…
Closed Angle Glaucoma
• In closed angle glaucoma, optic nerve damage and vision loss may
occur in the presence of an anatomical block of the anterior chamber
angle by the iris.
• This may lead to elevated intraocular pressure and optic nerve
damage.
• In acute angle closure glaucoma, the disease may be painful, needing
emergency care
86. Glaucoma conti…
Risk factors for the disease include:
• Racial background,
• Increasing age,
• Female gender,
• Positive family history, and
• Hyperopia.
88. Glaucoma conti…
• Assessment for glaucoma includes asking about complaints that may
relate to glaucoma such as vision loss, pain, redness, and halos around
lights.
• The onset, duration, location, and severity of symptoms should be
noted. All patients should be asked about family members with
glaucoma, and a detailed history should also be taken.
89. Glaucoma conti…
Common tests & procedures for the diagnosis of glaucoma:
• Tonometry: To measure the inner pressure of the eye.
• Ophthalmoscopy: To check the shape and color of the optic nerve.
• Perimetry: The patient’s ability to see the object clearly at several
points is checked during this procedure.
• Gonioscopy: To distinguish between open-angle and closed-angle
glaucoma.
• Pachymetry: To find out the thickness of the cornea.
90. Glaucoma conti…
• Treatment aims at reducing the intraocular pressure and preventing
further damage to the optic nerves.
• Intraocular pressure can be reduced by increasing the drainage of
aqueous humor or reducing its production through medications.
• Goniotomy is a procedure performed to treat infantile glaucoma.
• Trabeculectomy is the most commonly performed filtering procedure
in adults.
91. Glaucoma conti…
Different types of anesthesia can be used for glaucoma surgery such as:
• General anesthesia(LMA VS ETT??)
• Local anesthesia
• Topical anesthesia
In childrens general anesthesia is always indicated.
Anesthesia for glaucoma surgery in adults usually is performed with a
retrobulbar or peribulbar injection and, if needed, a facial nerve block.
92. Glaucoma conti…
The anesthesia management aims to
• Smooth induction and recovery to maintain IOP.
• Avoidance of venous congestion
• Avoidance of both over-hydration and hypotension
93. Regional anesthesia for ophthalmic surgical patients
Types of regional anesthesia for ophthalmic surgery:
• Sub-Tenon block(episcleral block)
• Peribulbar block (Extra-conal block)
• Retrobulbar block (Intra-conal block)
May be supplemented with IV sedation to avoid anxiety & discomfort,
and continuous monitoring is required.
95. Regional conti…
The retrobulbar block provides excellent akinesia and anesthesia of
the eye
A 3-cm, 23- to 25-gauge blunt Atkinson needle is recommended to
protect against ocular perforation
The needle is placed at the junction of the inferior and lateral walls
of the orbit just above the inferior orbital rim
96. Regional conti…
The needle is advanced about 15 mm along the wall of the orbit
until it is past the equator of the eye
The needle is turned superiorly to aim toward the superior orbit
The needle is advanced until it enters between the extraocular
muscles; 2 to 3 mL of anesthetic solution is injected.
Some intorsion on downgaze is expected because the superior
oblique muscle is outside the muscle cone and may not be blocked
98. Regional conti…
Complications RBB
• Retrobulbar hemorrhage
• Glob perforation
• Intravascular injection
• Penetration and injection of the optic nerve sheath which results in
optic nerve damage, subarachnoid spread, brainstem paresis and
cardiopulmonary arrest.
99. Peribulbar block
To prevent retrobulbar hemorrhage, posterior peribulbar anesthesia
has become more popular.
A blunt 23-gauge 7/8 inch Atkinson needle is placed at the junction of
the middle and lateral thirds of the lower lid just above the inferior
orbital rim;
1 mL of local anesthetic is put just below the orbital septum, 3 mL at
the equator, and 2 mL posterior outside the muscle cone.
If no bulging is noted at the superior nasal lid area, a second injection
of 2 to 3 mL is administered inferonasally.
