Considerations for Refractive Surgery in the Glaucoma Patient

Meleha Ahmad; Isaac Chocron; Anurag Shrivastava

Disclosures

Curr Opin Ophthalmol. 2017;28(4):310-315. 

In This Article

Abstract and Introduction

Abstract

Purpose of review Given the popularity of keratorefractive surgery, and an aging populous of patients who have undergone these procedures, there is an increasing need for updated management protocols. This is particularly relevant for patients with chronic progressive diseases such as glaucoma, due to the variety of related diagnostic and management challenges inherent to these diseases. Here, we will review the current literature to provide an update on the management of patients with glaucoma who are undergoing, or have had laser ablative refractive surgery. Preoperative testing and eligibility considerations, intraoperative factors, and postoperative observation and follow-up will be discussed.

Recent findings Intraoperative intraocular pressure (IOP) rise during flap creation is associated with low risk of acute complications, and furthermore do not appear to have significant long term effects. Modern technologies have improved our ability to determine accurate IOP after refractive surgery despite postoperative changes in corneal architecture. Furthermore, advances in structural imaging allow for earlier detection of even subtle glaucomatous nerve damage.

Summary Although glaucoma remains a relative contraindication to refractive surgery, it is a safe procedure for many patients with appropriate perioperative management and follow-up. Advancements in diagnostic modalities have allowed for earlier detection of glaucomatous disease, and subsequent earlier intervention when appropriate. Standardized diagnostic algorithms and rigorous perioperative assessment are critical to safe management of glaucoma patients undergoing refractive corneal surgery.

Introduction

With the improvement in refractive surgical techniques over the past several decades, there has been a dramatic rise in the number of people undergoing corneal laser procedures worldwide. In 2010, approximately 80 000 patients in the United States underwent corneal laser refractive procedures,[1] including photorefractive keratectomy (PRK), laser in-situ keratomielusis (LASIK) and laser in-situ epithelial keratomileusis (LASEK).

Despite its increasing popularity, successful ophthalmic evaluation post laser refractive surgery poses a few technical challenges, particularly when it comes to new glaucoma diagnosis and management of existing disease. Patients undergoing refractive surgery are frequently young myopes, who are at increased risk for development of not only primary open angle glaucoma,[2] but also additionally secondary glaucomas such as pigmentary[3] and steroid-induced subtypes.[4] Hyperopic patients undergoing corneal refractive surgery are at increased risk for acute angle closure glaucoma.[5] For these reasons, updated protocols for glaucoma diagnosis and management in patients with a history of refractive corneal surgery are imperative for clinical ophthalmologists.

Traditional methods of corneal applanation tend to underestimate intraocular pressure (IOP) after corneal refractive surgery procedures,[6,7] because of loss of corneal thickness and biomechanical changes.[8] This underestimation of IOP can prevent or delay proper diagnosis of new-onset glaucoma in patients with a history of corneal refractive surgery.[9] In addition, because IOP remains the only modifiable risk factor for glaucoma, unreliable IOP measurements derived from Goldmann applanation tonometry (GAT) can present a challenge for monitoring glaucoma progression and treatment response in patients post refractive surgery. Potential optical effects of corneal refractive surgery on acquisition of retinal nerve fiber layer (RNFL) thickness through optical coherence tomography (OCT) and birefringence have not yet been completely elucidated, and pose further challenges for diagnosis and monitoring of glaucoma following refractive surgery.

Another issue is the potential of glaucomatous damage and progression because of the refractive procedure itself. Although corneal refractive surgery is generally regarded as safe and well tolerated,[10] it remains possible that large transient IOP spikes during portions of the procedure may lead to structural alterations in highly susceptible patients. Perioperative complications related to topical steroids and other medications must also be accounted for. Additional studies of short-term and long-term outcomes of corneal laser procedures are needed to better understand the contribution of the procedure itself to glaucoma occurrence and progression.

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