BASICS

DESCRIPTION

• Cadaveric corneal transplantation

• Penetrating keratoplasty

• Lamellar keratoplasty

• Anterior

• Posterior

• Descemet’s stripping endothelial keratoplasty

• Descemet’s membrane endothelial keratoplasty

EPIDEMIOLOGY

Incidence

Complications are dependent on preoperative status of eye, skill of surgeon, intraoperative circumstances, and postoperative variables including medications and trauma.

RISK FACTORS

• Corneal neovascularization

• Glaucoma (1)

• Active corneal infection:

– Bacterial

– Fungal

– Herpes simplex

– Acanthamoeba

• Lens status:

– Cataract

– Intraocular lens

– Posterior capsule

• Anterior segment disorganization:

– Peripheral anterior synechiae

– Pupil/iris distortion

• Corneal hypesthesia

• Ocular surface abnormalities:

– Dry eyes

– Blepharitis

– Trichiasis

– Exposure

– Toxic medicamentosa

– Limbal stem cell deficiency

– Chemical burn

– Aniridia

• Steroid responsiveness

• Corneal dystrophy

Genetics

As related to various corneal dystrophies

GENERAL PREVENTION

• Control of intraocular pressure:

– Pre-op

– Intra-op

– Intravenous mannitol

– Avoid external pressure

– Post-op

• Meticulous surgical technique

• Anticipate problems

• Use of favorable donor tissue

• Preferable to operate on a quiet, noninfected eye

PATHOPHYSIOLOGY

• Corneal opacification:

– Edema

– Scarring

– Surface breakdown

– Infection

• Glaucomatous optic neuropathy

• Cataract

• Anterior segment disorganization

ETIOLOGY

• Intraoperative difficulties:

– Positive pressure

– Vitreous loss

– Choroidal effusion/hemorrhage

– Hyphema

• Immune rejection

• Endothelial failure

• Poor wound apposition/healing

• Elevated intraocular pressure

• Infection:

– Corneal ulceration

– Crystalline keratopathy

– Endophthalmitis

– Lamellar interface infection

COMMONLY ASSOCIATED CONDITIONS

• Glaucoma

• Complicated cataract surgery

• Ocular surface abnormalities

DIAGNOSIS

HISTORY

• Acute:

– Blurred vision

– Redness

– Photophobia

– Pain

– Discharge

– Lid swelling

– Trauma

• Chronic:

– Blurred vision

– Monocular diplopia

– Halos/glare

– Pain/irritation

– Redness

PHYSICAL EXAM

• Conjunctival injection/ciliary flush

• Corneal transplant edema

• Corneal transplant subepithelial infiltrates

• Corneal infiltrate/crystalline accumulation

• Corneal surface breakdown

• Corneal epithelial dendrite/geographic ulcer

• Lamellar interface haze/opacification

• Detached posterior lamellar graft (2)

• Secondary anterior chamber/detached Descemet’s membrane in deep anterior lamellar keratoplasty

• Anterior chamber reaction

• Keratic precipitates/endothelial rejection line

• Exposed sutures

• Wound leak/dehiscence

• Elevated intraocular pressure (3)

• Hypotony

• Cataract

• Recurrent corneal dystrophy

• Expanding curvilinear ridge on endothelium (epithelial downgrowth)

• Refractive error:

– High cylinder (4)

– Regular/irregular astigmatism

– High sphere

• Retinal/choroidal detachment

• Macular edema/pucker

DIAGNOSTIC TESTS & INTERPRETATION

Imaging

• When intraocular visualization obscured by corneal opacification

– B scan ultrasonography

– Ultrasound biomicroscopy

– Optical coherence tomography

• Serial pachymetry to monitor endothelial cell function

• Serial specular microscopy to monitor endothelial cell status

Diagnostic Procedures/Other

• When suspect infection:

– Corneal scrapings for cultures and smears

• Rigid contact lens refraction – if results in significant improvement in vision compared to spectacle correction it confirms irregular astigmatism as a source of reduced vision.

Pathological Findings

• Corneal edema

• Corneal scarring

• Corneal vascularization

• Corneal ulceration

• Corneal thinning

• Corneal inflammation

• Organisms on gram and/or various fungal stains

• Endothelial cell atrophy

• Recurrent corneal dystrophy (Bowman’s membrane, stromal, endothelial, keratoconus)

DIFFERENTIAL DIAGNOSIS

• Immune rejection vs nonimmunological endothelial failure

• Immune rejection vs herpes simplex keratouveitis

• Infectious vs noninfectious corneal ulcer/infiltrate/ulceration

• Immune rejection vs epithelial downgrowth

• Glaucoma vs steroid responder

• Regular vs irregular astigmatism

TREATMENT

MEDICATION

First Line

• Immune rejection:

– Topical steroid

– Topical cyclosporine

– Topical cycloplegia

• Infection:

– Topical antimicrobial therapy

– Topical cycloplegia

• Noninfectious epithelial breakdown:

– Topical lubrication, preferably preservative free

– Reduce use of toxic topical medications

– Punctal occlusion

• Glaucoma:

– Topical antiglaucoma medication

– Reduced topical steroid

• Astigmatism/anisometropia:

– Spectacle correction

• Contact lens correction

Second Line

• Immune rejection:

– Subconjunctival steroid

– Oral steroid

– Oral cyclosporine, tacrolimus

• Infection:

– Oral antimicrobial therapy

• Noninfectious epithelial breakdown:

– Bandage contact lens

– Oral omega 3 fatty acid supplementation

– Oral doxycycline

• Glaucoma:

– Oral carbonic anhydrase inhibitor

SURGERY/OTHER PROCEDURES

• Repeat keratoplasty for graft rejection/failure/scarring

• Permanent keratoprosthesis for repeat graft rejection/failure

• Glaucoma surgery for uncontrolled intraocular pressure

• Tarsorrhaphy, amniotic membrane transplantation, conjunctival flap, limbal stem cell transplant for persistent epithelial defect

• Refractive surgery (incisional astigmatic keratotomy ± compression sutures, wedge resection, excimer laser photorefractive keratectomy, lasik, intraocular lens, conductive keratoplasty) for high residual refractive error/anisometropia

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

Frequency of follow-up visits predicated by severity of the complication and integrity of the globe, i.e., daily for initial treatment of severe infection

Patient Monitoring

• Visual acuity

• Corneal clarity

• Intraocular pressure

PATIENT EDUCATION

Need to seek prompt evaluation at first signs of rejection/infection, i.e., blurred vision, pain, redness, photophobia, discharge, lid swelling.

PROGNOSIS

Depends upon original diagnosis and severity of complication. Ultimate visual recovery related to status of posterior segment

COMPLICATIONS (5)

Pediatric Considerations

• Children are more difficult to follow which leads to delayed diagnosis of complications. Repeated examinations under anesthesia are frequently necessary.

• High incidence of immune rejection occurs.

• Congenital corneal clouding frequently associated with anterior chamber abnormalities is present that increases risk for complications and reduces success rate of corneal transplantation.

• Amblyopia appears.

ADDITIONAL READING

• Rumelt S, Bersudsky V, Blum-Hareuveni T, et al. Preexisting and postoperative glaucoma in repeated corneal transplantation. Cornea 2002;2(18):759–765.

• Shih CY, Ritterband DC, Rubino S, et al. Visually significant and nonsignificant complications arising from Descemet stripping automated endothelial keratoplasty. Am J Ophthalmol 2009;148(6):837–843.

• Karadaq O, Kugu S, Erdogan G, et al. Incidence of and risk factors for increased intraocular pressure after penetrating keratoplasty. Cornea 2010;29(3):278–282.

• Bartels MC, van Rooij J, Geerards AJ, et al. Comparison of complication rates and postoperative astigmatism between nylon and mersilene sutures for corneal transplants in patients with Fuchs endothelial dystrophy. Cornea 2006;25(5):533–539.

• Michaeli A, Markovich A, Rootman DS. Corneal transplants for the treatment of congenital corneal opacities. J Pediatr Ophthalmol Strabismus 2005;42(1):34–44.

CODES

ICD9

• V42.5 Cornea replaced by transplant

• 370.8 Other forms of keratitis

• 996.89 Complications of other specified transplanted organ

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