Advanced techniques to improve surgical outcomes through tear film optimization

November 11, 2007

The condition of the ocular surface influences the outcome of cataract and refractive surgery and can also affect recovery following some surgical procedures.

The condition of the ocular surface influences the outcome of cataract and refractive surgery and can also affect recovery following some surgical procedures. The quality of the tear film and corneal epithelium is extremely important in obtaining good outcomes with multifocal and advanced technology IOLs.

Preparation for a successful outcome begins preoperatively, said Edward J. Holland, MD, professor of ophthalmology at the University of Cincinnati. He was one of several speakers at a morning continuing medical education symposium held at the Embassy Suites New Orleans-Convention Center. In patients with dry eye, clinicians should be alert preoperatively for conditions such as blepharitis, meibomian gland disease, and epithelial basement membrane degeneration, Dr. Holland said.

The preoperative examination should encompass lid anatomy and function, blink rate, legophthalmos, secondary exposure from blinking abnormalities, tear quality, and tear break-up time. The conjunctiva and corneal epithelium also should be closely examined using lissamine green staining. If any sign of staining is present, aggressive dry eye therapy should begin immediately, and it might be advisable to delay surgery until the ocular surface has improved, Dr. Holland said.

Cataract and refractive surgery change the ocular surface contours, which causes deterioration of dry eye symptoms and can lead to symptomatic ocular surface disease, according to Kerry D. Solomon, MD, the Arturo and Holly Melosi professor of ophthalmology at Storm Eye Institute, Medical University of South Carolina, Charleston.

"Our patients want to see better, sooner, and more distances than ever before, and this has reoriented a lot of what I do in my practice," Dr. Solomon said. He urged other clinicians to, like him, reorient themselves to be more proactive and aggressive not just with patients who will receive premium IOLs but with all patients. For instance, many older patients have co-existing cataracts and blepharitis, and he now vigorously treats the blepharitis with a variety of therapies before performing surgery. "It's made a big difference," he noted.

Lubricants are the mainstay of treatment for dry eye. Dr. Holland said he no longer reserves preventive medicines for the most aggressive cases. If topical lubricants do not resolve the problem, he will quickly move to topical cyclosporine and use it in mild cases as well as moderate-to-severe dry eye.

"This has made a huge impact on my LASIK practice, where not only do we reduce dry eye, but it also improves my outcomes, my vision, and contrast sensitivity and Snellen acuity," he said.

Dr. Holland also mentioned that he routinely uses optical coherence tomography (OCT) preoperatively to determine whether patients are suited for implantation of a premium lens. Using OCT, he has found many more epiretinal membranes then when using a slit lamp. The subtle pathologic findings obtained with OCT may influence the clinician's decision on the appropriate lens for the patient, he added.

"There's a lot you can do therapeutically that will make a big difference in the outcome of your patients," he added.

Patients who are at risk of developing dry eye following cataract or corneal refractive surgery should be identified and appropriate measures taken to obtain a favorable outcome, said Stephen S. Lane, MD, clinical professor of ophthalmology, University of Minnesota, Twin Cities, Minneapolis.

To protect the ocular surface during cataract surgery, begin with the preoperative steps of pupil dilation, antimicrobial prophylaxis, and analgesia. Either preserved or preservative-free agents, such as intraoperative intracameral application of epinephrine, may be used to dilate the pupil and numb the ocular surface, Dr. Lane said. Likewise, either preserved or preservative-free fourth-generation fluoroquinolones can be used for antimicrobial prophylaxis. Preservative-free lidocaine jelly can be used for analgesia of the ocular surface.

Proper lid and lash draping is one of the critical steps in ocular preparation. The drape should go over the lashes and under the meibomian gland orifices to protect the surface from meibomian gland oils that could limit the surgeon's visualization.

Intraoperative measures to protect the ocular surface include minimizing the incision size, which reduces the number of corneal nerves that are cut, and frequently lubricating the surface. Postoperatively, the main objective is to reduce the frequency and length of time of topical medications. If the patient has pre-existing or concurrent ocular disease, supplemental preservative-free artificial tears are recommended, along with longer-term topical steroids and cyclosporine A, Dr. Lane said.

Preparations to protect the ocular surface during corneal refractive surgery depend on whether the patient has no ocular surface disease, minimal-to-moderate disease, or severe disease.

Today's clinicians have access to promising new products such as multifocal and advanced technology IOLs, including an aspheric IOL that provides up to 53% better contrast sensitivity under mesopic conditions when compared with a conventional IOL. But such advances will be of little benefit if the ocular surface is even slightly disrupted, said Eric D. Donnenfeld, MD, FACS, founding partner of Ophthalmic Consultants of Long Island, Rockville Centre, NY.

Disruption of the ocular surface induces distortion that is not correctable with an aspheric IOL and is magnified by a multifocal IOL, Dr. Donnenfeld said. Disruption of the tear film also magnifies the glare and halo inherent in all multifocal IOLs.

Dr. Donnenfeld also noted that a common patient complaint, visual fluctuation, is unquestionably diagnostic of ocular surface disease. If a patient has vision changes between blinks, at different times of the day, or after prolonged effort, treatment should be begun promptly.

He recommended preoperative and postoperative use of topical cyclosporine A when performing multifocal IOL implantation. A paper in press by Dr. Donnenfeld and colleagues found significantly better visual acuity with cyclosporine in a randomized study in which patients received the drug b.i.d. in one eye and artificial tears b.i.d. in the other.

Cyclosporine also improved contrast sensitivity in mesopic conditions without glare and photopic conditions with glare, and 57% of patients preferred their cyclosporine-treated eyes.