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William B. Trattler, MD

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	The majority of cataract patients likely have significant tear film disturbances that can affect their preoperative measurements and postoperative satisfaction with cataract surgery.

	By William B. Trattler, MD, and Jodi Luchs, MD, Special to 

	Two prospective studies conducted recently both found that, while the majority of patients presenting for routine cataract surgery are asymptomatic, a large proportion of these patients do have clinically significant ocular surface disease.

	If not addressed, tear film problems can lead to errors in IOL power selection, slow down healing and visual recovery, and reduce postoperative satisfaction and quality of vision, particularly in refractive cataract surgery with a premium IOL.

	The Prospective Health Assessment of Cataract Patients’ Ocular Surface (P.H.A.C.O.) study was conducted at nine clinical sites across the United States.

	In all, 136 patients (272 eyes) presenting for routine cataract surgery were examined for signs and symptoms of dry eye prior to surgery. The average age was 70 (range 54 to 87) years. About 22% of the patients had been told at some point in the past that they had dry eyes.

	While experts debate what constitutes an abnormal tear film break-up time (TBUT), the typical values proposed as “abnormal” are <10 seconds or < 7 seconds.

	However, most would agree that 5 seconds is too rapid. Surprisingly, the average TBUT in the PHACO study was 4.95 seconds, and 171 eyes (63%) had a TBUT of ≤ 5 seconds.

	Most of the eyes (77%) had some corneal staining, but what was more concerning is that half of them had central corneal staining, which can certainly affect visual outcomes.

	Although we generally view the Schirmer test as less useful for routine dry eye screening, one-fifth of the patients also had abnormally low Schirmer test scores (<5 mm) (Figure 1).

If not addressed, tear film problems can lead to reduced postoperative satisfaction and outcomes. (Figures courtesy of William B. Trattler, MD)

	In another prospective study with very similar methodology, looking at the prevalence of blepharitis, we (along with Carlos Buznego, MD) enrolled a total of 200 eyes of 100 patients presenting for routine biometry prior to cataract surgery.

	Following an ocular surface examination, 59% of the patients in this study had a diagnosis of blepharitis. Sixty-one percent had a TBUT of ≤ 7 seconds.

	As cornea and external disease specialists, we aren’t all that surprised by the results in either of these studies. What is striking is that the majority of the patients were asymptomatic or minimally symptomatic.

	Although this surprised us initially, it does explain why ocular surface disease so often goes undiagnosed preoperatively. The patients are not complaining about it; the surgeon is focused on the primary complaint (cataract); and no one is really thinking about treating the ocular surface.

	But failing to identify and treat dry eye prior to cataract surgery can lead to reduced visual outcomes. Either rapid TBUT or corneal staining will significantly affect keratometry and topography, reducing the accuracy of preoperative IOL power calculations. Ocular surface disturbances can significantly alter the magnitude or axis of cylinder, affecting planning for limbal relaxing incisions or toric IOLs.

	Moreover, once the cataract has been removed, visual fluctuations and quality-of-vision problems will become much more noticeable, even if the patient continues to be asymptomatic.

	In the past, when patients expected to see 20/40 with glasses by 6 weeks, subtle ocular surface issues and even IOL power errors may not have mattered as much.

	In today’s environment, when patients undergo a 10- to 15-minute procedure under topical anesthesia and have the potential (with a premium IOL) for 20/20 distance and near acuity within days of surgery, these subtle sources of error or visual compromises become much more relevant to successful management.

	Data suggest that cataract surgeons should have a high index of suspicion about dry eye and blepharitis and take steps to identify and treat these conditions prior to taking preoperative measurements for cataract surgery.

	Short-term management of moderate dry eye or blepharitis to optimize the ocular surface for surgery is well within the skill set of any ophthalmologist. It does not require corneal training or specialized testing equipment, and it need not be time-consuming or disruptive to your preoperative flow.

	Here are three steps that take only a few minutes preoperative, but can save lots of chair time and headaches postoperatively:

	1.     Look for dry eye with corneal staining, TBUT, and topography.

	2.     Look for blepharitis/meibomian gland disease (MGD) by examining the lid margins and applying pressure to express the meibomian glands.

	3.     If you see rapid TBUT, MGD or corneal staining, treat the patient for 1 to 2 weeks before the biometry appointment with cyclosporine, topical steroids, nonpreserved artificial tears, and potentially punctal plugs (dry eye) and/or with warm compresses and topical azithromycin (blepharitis/MGD).

	Alterations to the treatment regimen may be needed for longer-term management, but this regimen will get most patients in good enough shape for accurate biometry in a relatively short period.

	By routinely screening for ocular surface disorders-even in the absence of complaints-surgeons will be able to improve mean outcomes incrementally with premium IOLs across the board

	For patients for whom ocular surface disorders might have led to a less-than-satisfactory outcome-the wrong IOL power implanted, for example-the impact can be great.

	We often see unhappy postsurgical patients referred for consultation who simply have dry eye or blepharitis. Once the tear film is stabilized, visual quality improves dramatically and dissatisfaction disappears.

	It would be better to avoid such problems in the first place. In one of Dr. Trattler’s recent multifocal IOL patients, preoperative measurements pointed to a 20-D multifocal IOL (Tecnis Multifocal, Abbott Medical Optics) as the best choice.

	However, the topography had a lot of missing data, suggesting an unstable tear film. Dr. Trattler elected to treat the patient with cyclosporine and topical steroids.

	When the measurements were repeated a week later, the keratometry had changed significantly. The patient received a 21-D lens and a great result from surgery.

	Topography is a wonderful screening tool. In another case, a 58-year-old male with visually significant cataract in the left eye, who was interested in a premium IOL, we can see how the topography changes with treatment over just 1 day and 1 week (Figures 2a to c).

	Ocular surface disease in the cataract population is far more common than most people believe.

	Given this, it is critical to have a high index of suspicion of dry eye and blepharitis. If ophthalmologists look for it even in asymptomatic patients, they can make the diagnosis and treat the ocular surface prior to surgery to maximize the chances of delivering the refractive results that patients expect.

		Trattler W, Reilly C, Goldberg D, Majmudar P, Vukich J, Packer M, Donnenfeld E. Cataract and dry eye: Prospective Health Assessment of Cataract Patients’ Ocular Surface Study. Poster, American Society of Cataract and Refractive Surgery Annual Symposium and Congress. San Diego; March 2011.

		Luchs J, Buznego C, Trattler W. Incidence of blepharitis in patients scheduled for phacoemulsification. Presentation, American Society of Cataract and Refractive Surgery Annual Symposium and Congress. Boston; April 2010.

	Dr. Trattler is director of cornea, Center for Excellence in Eye Care, Miami, and volunteer assistant professor of ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine. Readers may contact him at 305/598-2020 or 

. Dr. Trattler is a consultant and speaker for Abbott Medical Optics, Allergan, and Bausch + Lomb.

	Dr. Luchs is co-director, Department of Refractive Surgery, North Shore/Long Island Jewish Medical Center; director of cornea and external disease, South Shore Eye Care, Wantagh, NY; and assistant clinical professor of ophthalmology, Hofstra University School of Medicine, New York. Readers may contact him at 516/785-3900 or 

. Dr. Luchs did not indicate any proprietary interest in the subject matter.

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The majority of cataract patients likely have significant tear film disturbances that can affect their preoperative measurements and postoperative satisfaction with cataract surgery.

What cataract surgeons don’t know can hurt premium IOL outcomes

It is vital to identify and prevent dry eye and blepharitis pre-surgery because these conditions can affect IOL calculations (inaccurate keratometry can lead to incorrect IOL power); limbal relaxing incisions, or toric IOL axis and/or magnitude; and inaccurate topography, which can hinder visual results and surgical outcomes. 

It is vital to identify and prevent dry eye and blepharitis pre-surgery because these conditions can affect IOL calculations and more.

Treat, prevent dry eye prior to cataract surgery

Refractive surgeons are realizing that providing a single refractive procedure for the lifetime of a patient is less common. A "vision-for-a-lifetime" approach-where surgeons offer multiple refractive procedures to suit the visual needs of the different stages of a patient's life-is replacing the "catch-and-release" model.

As the subspecialty matures, we are faced more commonly with opportunities to offer enhancements after LASIK. As a result, we are learning more about the potential challenges with lift-flap enhancements such as epithelial ingrowth. With the increasing use of prophylactic mitomycin C (MMC) for the prevention of haze, and the avoidance of the epithelial ingrowth, more surgeons are turning to PRK for enhancements.  

In this month's column, William B. Trattler, MD, provides an overview of LASIK enhancements and explains why he frequently uses PRK for this purpose.

It is not uncommon for patients who have had laser refractive surgery more than a decade ago to come in to one's office looking for solutions to changes in their vision over the past few years. 

The evaluation process is similar to that of a patient who has not had surgery. Corneal topography is critical to ensure that the ablation is centered and the optical zone is of reasonable size. As well, the topography should be evaluated to determine whether any signs of early ectasia are present. 

Another consideration is the overall keratometry value. If the central K measurements are very flat or very steep, and surgery is required that will flatten or steepen the cornea further, then the patient may not be the best candidate for a laser vision correction enhancement. Corneal topography also is a useful tool for evaluating the tear film. An unstable tear film will show up on corneal topography as focal areas of irregularity or even areas of image drop-out. 

Evaluating the refractive error also is critical. The refraction should be stable before an enhancement is performed. As well, if the patient's vision is not correctable to 20/20, the reason for reduced vision should be explored extensively. 

One common cause of a refractive shift and mild loss of best-corrected visual acuity (BCVA) is the development of an early cataract. Other causes of reduced BCVA include EBMD, ocular surface disease, and macular conditions. Of these conditions, ocular surface disease caused either by dry eye or blepharitis is treatable, and some patients who have their ocular surface disease successfully treated may experience improvement in their overall quality of vision and decide that further surgery is unnecessary. 

William B. Trattler, MD, provides an overview of LASIK enhancements and explains why he frequently uses PRK for this purpose.

William B. Trattler, MD

Articles

What cataract surgeons don’t know can hurt premium IOL outcomes

Treat, prevent dry eye prior to cataract surgery

Surgeons look to PRK to enhance previous LASIK

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