Corneal Edema After Cataract Surgery

Key Points

The etiology of postoperative corneal edema is broad.
Thorough preoperative evaluation can help elicit patients at higher risk for postoperative corneal edema.
Corneal edema can lead to acute and chronic changes in visual acuity and to eye pain.
Management is tailored to the patient’s specific cause of corneal edema but can involve hypertonic solutions, antiinflammatory therapies, Descemet’s membrane reattachment, intraocular lens (IOL) exchange, and/or corneal transplantation.

Introduction

Corneal edema after cataract surgery is not uncommon and is typically localized around corneal incisions. More significant corneal edema after cataract extraction is an uncommon but well-known complication of cataract surgery. The most severe form of irreversible corneal edema, referred to as pseudophakic bullous keratopathy (PBK), occurs in about 1% of patients after traditional cataract surgery but can climb to 11% to 24% in patients with <1000 endothelial cells/mm ² . Postoperative corneal edema can vary in location from superficial epithelial swelling to full-thickness edema. Though most postoperative edema will resolve with time, a variety of management options can be employed to expedite and increase the likelihood of recovery. Management of postoperative corneal edema is critical in achieving optimal patient satisfaction and anatomic outcomes.

This chapter reviews the differential diagnosis and treatment of corneal edema after cataract surgery. Chapter 37 addresses combined corneal and cataract surgery in patients with preoperatively compromised corneas.

Causes

A variety of risk factors are associated with reduced endothelial cell density and resultant postoperative corneal edema. Given that the central endothelial cell density has been shown to decrease by as much as 8.4% at 1 year after phacoemulsification cataract surgery, it is imperative to identify patients at increased risk for corneal decompensation to potentially avoid, or expeditiously treat, corneal edema. Table 50.1 lists the principal risk factors and causes of postoperative corneal edema after cataract surgery.

Table 50.1

Risk Factors and Causes of Corneal Edema After Cataract Surgery

Preoperative	Intraoperative	Postoperative
Advanced age	Surgical trauma	IOL * -related
Lower endothelial cell count found in the following ethnicities: Japanese, Chinese, Filipino, and American	Toxic anterior segment syndrome (TASS) & chemical injuries	Retained lens fragment
Medications	Increased phacoemulsification power	Membranous ingrowth
Systemic Diseases	Descemet’s membrane detachment	Inflammation
Dense cataract		Glaucoma
History of ocular disease, surgery, or trauma		Brown-McLean Syndrome
Corneal endothelial dystrophies
Shallow anterior chamber

* IOL, intraocular lens.

Preoperative

Advanced Age

Endothelial cell density decreases physiologically with time ( Table 50.2 ).

Table 50.2

Endothelial Cell Density by Age

Endothelial Cell Density by Age
Age (years)	Cell Density (mean ± SD cell/mm ² )
6–20	3101 ± 268
20–29	2843 ± 285
30–39	2798 ± 247
40–49	2714 ± 263
50–59	2632 ± 277
60–69	2558 ± 233
>70	2571 ± 283

Ethnicity

Variation in endothelial cell counts by ethnicity have been reported, with lower cell counts in Japanese, American, Chinese, and Filipino eyes, while higher counts have been identified in Indian, Thai, and Iranian eyes.

Medications

Systemic medications, such as amantadine used for Parkinson’s disease, and topical medications, such as carbonic anhydrase inhibitors, can affect endothelial cell function.

Systemic Diseases

Medical conditions such as chronic obstructive pulmonary disease, diabetes mellitus, and renal insufficiency are associated with decreased endothelial cell count and function.

History of Ocular Disease, Surgery, or Trauma

Patients with a history of glaucoma, particularly angle-closure glaucoma, uveitis, and pseudoexfoliation syndrome are associated with reduced endothelial cell density. Patients with a history of same eye trauma or anterior segment, glaucoma, or retina-related surgery are also at risk for decreased endothelial cell density.

Shallow Anterior Chamber

Shallow anterior chambers and short axial lengths that decrease the distance between the cornea and phacoemulsification tip expose the endothelium to higher levels of ultrasound energy and increase the risk for endothelial cell loss during surgery.

Dense Cataract

Dense nuclear cataracts require higher levels of ultrasound energy for increased lengths of time and are at higher risk for increased chatter and turbulence during phacoemulsification.

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