Tips and techniques for cataract and refractive success: The dry eye connection

November 10, 2008

Dry eye disease and cataract and refractive surgery are intertwined closely. Pre-existing dry eye can affect surgical outcomes and, in severe cases, is a contraindication for surgery, whereas surgery causes trauma to the ocular surface and may lead to signs and symptoms of dry eye. To break this cycle, a two-pronged approach of treating dry eye before surgery and taking steps to prevent its development postoperatively is advisable.

Dry eye disease and cataract and refractive surgery areintertwined closely. Pre-existing dry eye can affect surgicaloutcomes and, in severe cases, is a contraindication for surgery,whereas surgery causes trauma to the ocular surface and may leadto signs and symptoms of dry eye. To break this cycle, atwo-pronged approach of treating dry eye before surgery andtaking steps to prevent its development postoperatively isadvisable.

Dry eye is believed to be one of the most commonly diagnosedocular conditions in the United States and is particularlyfrequent among older women. It is likely, though, that manypeople who suffer from dry eye have never been diagnosed by aneye-care professional, and prevalence may be grosslyunderestimated. Various estimates place the number of dry eyesufferers in the United States at 20 to 55 million.

Regardless of the true prevalence, the numbers are unquestionablyhigh, and preoperative screening is a sound strategy, saidMarguerite McDonald, MD, clinical professor of ophthalmology atNew York University of Medicine, New York, and also at TulaneUniversity Health Sciences Center, New Orleans.

Speaking at a continuing medical education symposium held duringthe American Academy of Ophthalmology annual meeting in Atlanta,she proposed guidelines for cataract or refractive surgery anddry eye disease. A patient who has dry eye symptoms that have noeffect on vision is usually a good candidate, while someone whosesymptoms cause fluctuating vision is a moderate to poorcandidate. If the symptoms cause decreased vision due to ocularsurface disease, surgery should be postponed until the patient'scondition has improved with treatment.

Signs of disease also can help evaluate a patient's preoperativestatus. A good candidate for surgery will have no supravitalconjunctival staining, whereas a moderate candidate would havesupravital conjunctival staining but no corneal staining. Anoncandidate, at least until the condition of the eyes hasimproved with treatment, is one who has supravital conjunctivalstaining plus central fluorescein conjunctival staining, Dr.McDonald explained.

Another speaker at the breakfast symposium, held at the AtlantaMarriott Marquis, explained that while advanced technology hasimproved safety and visual quality for cataract and refractivesurgery, there is a downside as well. Edward J. Holland, MD,professor of ophthalmology at the University of Cincinnati anddirector of Cornea Services at the Cincinnati Eye Institute, saidthat disruption of the ocular surface induces distortion, whichis magnified by a multifocal IOL. The most common source ofdecreased visual acuity and dissatisfaction among patients whohave been implanted with a premium lens is ocular surfacedisease, he added.

Cataract surgery causes trauma to the corneal nerves by cuttingthese nerves at the limbus; the phaco incision, paracentesis, andrelaxing incisions add to the trauma, Dr. Holland said. To reducethe severity of postsurgical dry eye, he recommended thatappropriate preventive measures be taken at several time points.Preoperatively, patients at risk of dry eye should be identifiedand treatment offered to maximize tear film stability.Dr. Holland suggested that it is preferable to disappoint apatient by delaying surgery for a short time than to face theconsequences of significant postoperative problems such asfluctuating vision that impairs visual acuity for severalmonths.

Intraoperatively, dry eye promoters should be minimized and theepithelium protected. Postoperatively, therapeutic interventionshould be applied.

The symptoms of dry eye vary and may include tearing, discomfort,dryness, burning, stinging, irritation, blurry vision, a grittyfeeling or stickiness, itching, photophobia, or redness. Thesesymptoms may not correlate with the clinical signs, whichincrease the difficulty of making an accurate diagnosis, saidEric D. Donnenfeld, MD, a partner in Ophthalmic Consultants ofLong Island and a clinical professor of ophthalmology at New YorkUniversity.

The most useful symptom for diagnosing ocular surface disease,however, is fluctuating vision, Dr. Donnenfeld said. Thisfluctuation includes vision changes between blinks, at differenttimes of the day, and after prolonged effort.

Clinicians also can gain clues by observing their patients andstudying their history. Older patients and perimenopausal andpostmenopausal women, for example, are at higher risk, as arecigarette-smokers, patients who wear contact lenses, have anautoimmune disease, or have had cosmetic eyelid surgery.

Corneal staining with lissamine green also is beneficial andtends to be an accurate diagnostic tool, Dr. Donnenfeld added. Healso pointed out that not all dry eye cases are aqueous and thatkeratoconjunctivitis sicca also can affect the outcomes ofcataract and refractive surgery. Dr. Donnenfeld was chairman andmoderator of the program as well as a speaker.

Stephen C. Pflugfelder, MD, also emphasized the importance of ahealthy, stable tear film as an essential component forhigh-quality visual function. To this end, physicians shouldidentify and treat patients with dry eye and corneal epithelialdisease preoperatively. If corneal epithelial disease does notresolve, the patient is not a good candidate for a multifocal IOLor LASIK, said Dr. Pflugfelder, professor and James and MargaretElkins Chair, Department of Ophthalmology, Baylor College ofMedicine, Houston.

According to a recent study, dry eye patients have a significantdecrease in their low-contrast visual acuity compared to theirhigh-contrast acuity. Dr. Pflugfelder recommended that cliniciansuse low-contrast acuity as a screening tool for dry eye.

Clinicians also may want to perform preoperative topography andwavefront on their cataract and refractive surgery patients tohelp assess the status of their eyes.

This continuing medical education activity was jointly sponsoredby the New York Eye and Ear Infirmary and cme² inpartnership with Ophthalmology Times, and was supportedthrough an unrestricted educational grant from Allergan.

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