What is an ophthalmic emergency? And what to do with it (Proceedings)

True Emergencies

• Acute Primary Glaucoma

• Luxated Lens

• Globe Proptosis

• Corneal Laceration

• Deep/Progressive Ulceration

Emergency #1

Acute Primary Glaucoma

• ACUTE: Often occurring over hours

• PRIMARY: Developing in absence of an overt underlying cause

• GLAUCOMA: Pathologic elevation in IOP

• Inherited abnormality of the ICA places certain animals at risk (breed and individual variation)

Poster Children: Classic Exam Findings

• Blepharospasm

• Elevated TE

• Corneal edema

• Episcleral congestion

• Fixed, dilated pupil

• Vision loss

Diagnostics

• IOP>>25 mmHg

• Hyperemic ON

• Do NOT pharmacologically dilate!

Why it's an Emergency

• Exquisitely painful condition

• Permanent vision loss occurs over hours with greatly elevated IOP

• Vision loss by degenerative optic neuropathy*

• The higher the IOP, the less time required for permanent blindness

• The globe is buphthalmic*

• The dog lost vision last month

• The patient is a cat

When in Doubt...Mannitol

Fwiw

Beyond ER Treatment

• Prompt referral for further evaluation & treatment, options

• Gonioscopy of ICA to confirm primary glaucoma

• Surgical procedures are available for visual globes that may be useful to control IOP for very committed clients

o Laser TSCP

o Goniovalve placement

Long-Term Consequences

• Ultimately

o BLINDING

o PAINFUL

o BILATERAL

Long-Term Options

• Topical anti-glaucoma tx has been shown to delay the onset of primary glaucoma given prior to IOP elevation

o ** TREAT THE OTHER EYE**

• Chronic glaucoma usually ultimately requires some sort of surgical salvage procedure

o Enucleation

o Evisceration with intrascleral prosthetic placement

o Cyclocryoablation

o Pharmacologic ciliary body ablation

Emergency #2

Primary Lens Luxation

• Many terrier breeds have a primary lens zonule abnormality

• Zonules gradually break down spontaneously until lens comes loose around middle age

• Occasionally will see what appears to be a senile breakdown in older poodles, etc.

• Differentiate from luxation due to chronic inflammation, buphthalmia, trauma

Lens Luxation

Poster Children:Typical Lens Lux Patient

• JR Terrier

• Middle aged

• Acute, severe blepharospasm, red eye, serous discharge, corneal edema

Common Exam Findings

• Aphakic Crescent

• Lens visible in AC

• Cataract occurs with chronicity

• Normally see cataract within pupillary region

• In this case, opacity overlies the iris so pupil and iris cannot be ID'd

Other Common Exam Findings

• Iridodonesis

• Phacodonesis

• Vitreous in same or contralateral AC

• Corneal edema

• Elevated IOP

• Fuzzy view of posterior chamber (Do not dilate!)

Why it's an Emergency

• Luxation itself is often very painful*

• Can result in rapid elevation in IOP- which is painful and rapidly vision threatening

• Early treatment decreases- but does not eliminate- long-term risk of retinal detachment, glaucoma, blindness

• Occurs in a buphthalmic globe

• Occurs in a cat

• Occurs posteriorly

• Occurs in a permanently blind globe

• Client will not consider surgery

Diagnosis Of Glaucoma Due to Lens Luxation

• Secondary to

Pupillary block

ICA obstruction

Uveitis

• Use applanation tonometer if possible

o Lens location beneath cornea may result in artificially elevated value by Schiotz

Medical Therapy

• Anti-glaucoma agents as needed*

• Topical anti-inflammatories

• Systemic anti-inflammatories

• Avoid drugs that affect pupil size

• YES- mannitol, methazolamide, Trusopt

• NO- Xalatan, pilocarpine, demecarium, atropine, tropicamide

Surgical Therapy

• PROMPT referral for LENSECTOMY!

• Not typical elective cataract surgery in which the inside of the lens is emulsified and removed through a small incision, leaving a capsular bag for placement of an artificial lens

• Instead, higher risk intracapsular extraction in which whole lens and capsule removed in one piece through a large corneal incision

Long-Term Consequences

• Chronic secondary glaucoma not uncommon

• Retinal detachment risk due to surgical hypotony, post-op from inflammation, vitreal traction bands

• Aphakic patients are far-sighted and probably have impaired stereopsis *

• Dogs with primary lens lux in one eye are at great risk of having same process occur in the other eye

o client education

o consider treatment of other eye with a miotic agent

Latest Treatment Philosophy

• If signs of visual capacity, and comfort can be maintained medically, ...

• Control inflammation, IOP

• Laser retinopexy to prevent post-op RD

• Planned lens extraction 2-4 wks later

Emergency #3

Globe Proptosis

• Anterior displacement of the globe from the orbit

• Due to some sort of trauma

o Hit by car

o Dog bite

o Member of a multi-pet household left unsupervised together

o Excessive restraint (brachycephalics)

Poster Children: Exam Findings

• Globe anteriorly displaced

• No visible lid margins

• Periocular bruising and edema

• Scleral hemorrhage

• Painful!

Why it's an Emergency

• Damage occurs via several mechanisms

o Stretched optic nerve

o Compromise of vascular supply to globe

o Extraocular muscle avulsion

o Exposure keratitis

• Periocular swelling which occurs with any significant delay compounds the problem

• Rapid replacement is crucial to prognosis for globe salvage, vision, and cosmesis!!

• ...THE PATIENT IS NOT STABLE

• Treat life-threatening injuries first

• Protect globe, keep moist, lubricate

• Then replace ASAP

Poor Prognostic Indicators

• Non-brachycephalic dog

• Any cat

• Hyphema

• Avulsion of 3 or more extraocular m.==> ==> ==>

• Absent consensual PLR

• Presence of facial fractures

• Abnormal fundus

• Significant delay in replacement

• Size of pupil is not good indication of visual prognosis

Surgically Replace Globe Asap!!

• General anesthesia

• Lubricate, lubricate!

• Preplace sutures?

• Lateral canthotomy?*

• Replace globe by gentle traction

• Temporary tarrsorrhaphy ± stents

Medical Therapy

• Lubricate

• Cover with topical AB

• Minimize self-trauma

• Systemic anti-inflammatory

• Consider risks and benefits of dilating pupil

• BNP

• E-collar

• Prednisone

• ± atropine

Refer for Follow-Up

• Staged suture removal

• Evaluation for complications

• Long-term prognosis

• Consider permanent medial canthoplasty for brachycephalics*

Possible Long-Term Consequences

• Blindness

• Strabismus

• Decreased corneal sensitivity

• Keratoconjunctivits sicca

• Corneal ulcer

• Uveitis, glaucoma, cataract

• Retinal detachment, retinal degeneration

• Optic nerve degeneration, avulsion

• Phthisis bulbi

Emergency #4

Corneal Laceration

• "New dog meets old cat" syndrome!!

Typical Corneal Laceration

• Acutely painful eye

• Curvilinear corneal lesion

• Variable degree of

o Corneal edema

o Intraocular hemmorhage/fibrin

o Leaking from site

o Miosis

o Vision loss

Simple Corneal Laceration

• Place on topical and systemic AB

• Systemic anti-inflammatory

• Atropine

• E-collar!!!

• Use drops not ointment

• Refer- this is almost always a surgical condition- even if it initially self-seals

• Prognosis for simple clear-corneal lacerations treated like this and having cornea direct-sutured within 12-24 hrs using 8-0 to 10-0 suture is very good- for both eye and vision

Complicated Corneal Laceration

• Lots of other structures to damage:

• Iris ==> hyphema

o ==> possibly glaucoma, blindness if severe

• CB ==> possible globe atrophy down road

• Lens==> cataract or worse***

Cornea and Lens Laceration

• Lens rupture has serious consequences

o Small (<1.5mm) lens ruptures may self-seal resulting only in focal cataract

o Larger ruptures release such a large amount of lens protein into eye that it overwhelms the eye's T-cell tolerance

Cornea and Lens Laceration

• The severity of phacoclastic uveitis is attributed to the developmentally sequestered nature of lens protein

o i.e. tolerance to these "self" proteins never develops

• Such uveitis is refractory to even aggressive anti-inflammatory treatment

• May also be implantation of bacteria into lens

Cornea and Lens Laceration

• Simultaneous or early lens removal can still result in a good outcome

• Long-term prognosis is probably better in an adult than in puppy/kitten

Emergency #5

Deep/ Progressive Corneal Ulcers

Examples

• Iris Prolapse

• Descemetocele

• "Melting" ulcer

Deep/Rapidly Progressive Ulcers

• No true breed predisposition, but brachycephalics more prone to ulcers in general than others

• Rapid progression in depth often due to bacterial infection of a simple ulcer

• Cornea can heal simple ulcers without difficulty, but lack of blood supply delays healing response to infection

Medical Treatment

• Lesions >=50% depth or rapidly progressive are most safely treated with surgery, but medical treatment important pre- and post-op

• Medical treatment like corneal laceration

• Exception is "melting" ulcer

• Very frequent administration of topical antibiotics and anti-proteases

o EX: ofloxacin, cefazolin- fortified tears, serum/plasma

o 6-24X daily each

o Don't forget to culture 1st!

Surgical Treatment

• Should recommend referral

• TE flaps usually not recommended b/c cannot monitor progression & may block medications

• Several alternatives: Conjunctival grafts (pedicle, island, etc.), corneoconjunctival transposition flaps, corneal transplants, biosynthetic grafts, etc.

Pros and Cons of Surgeries

Conjunctival Pedicle Graft

Pros and Cons of Surgeries

Corneoconjunctival Transplantation

Lamellar Corneal Grafts

• VOv2p233-241 '99

Penetrating Keratoplasty/Corneal Transplant

Biosynthetic Grafts