Evaluate tear film before surgery

San Diego-The key to the best visual results after cataract and refractive surgery rests with optimizing the ocular surface in patients with dry eye disorders prior to the procedure. Elmer Tu, MD, explained why this is so important and how to achieve a healthy ocular surface during Cornea Day at the annual meeting of the American Society of Cataract and Refractive Surgery.

Underestimated dry eye effects

While patients seeking refractive surgery are generally younger, many of these candidates are unhappy with their current visual status due to contact lens intolerance and unstable vision, which often can be signs of a tear film disorder and should be evaluated. Undergoing an anterior segment procedure in and of itself exposes the ocular surface to trauma and the additional toxicities of the preoperative and postoperative medications will activate the inflammatory cascade of the anterior segment.

Further, some reduction of corneal sensitivity, sometimes profound, is expected with all corneal procedures including cataract and laser refractive operations, resulting in changes in corneal epithelial physiology, Dr. Tu explained.

"In [patients undergoing] cataract and refractive surgery, the abnormal tear film [affects] outcomes preoperatively, intraoperatively, and postoperatively," he said.

Unstable tear film increases higher-order aberrations in patients undergoing refractive surgery, as well as causing irregular mires, inaccurate keratometry readings, or altered astigmatism readings. Any of these can result in a small, but visually significant shift in the planned axis of placement for toric lenses and very symptomatic inaccuracies of IOL power calculations for multifocal IOLs, negatively affecting the target visual acuity.

Intraoperatively, epithelial irregularity and fragility can interfere with surgeon visualization and cause epithelial defects and retinal detachments, which can lead to extended recovery time and patient dissatisfaction. Endophthalmitis and wound infections are also potential complications in patients with untreated ocular surface disease.