Postoperative refractive surprises have no place in the modern era of cataract and refractive surgery. One of the most effective strategies surgeons can use to minimize unexpected visual outcomes is to evaluate and treat the ocular surface to optimize the health and quality of the tear film prior to performing pre-surgical testing. Specifically, the cataract or refractive surgery consultation should be decoupled from pre-surgical diagnostics.

Most of our surgery patients suffer from preexisting ocular surface disease (OSD), which the surgery itself can exacerbate. In addition, consider how the consultation affects the cornea and tear film.

We strain this delicate biological environment with vital dyes, stress it with mydriatic agents and proparacaine, push on it with an applanation tonometer, and accentuate tear evaporation by the bright lights of our indirect ophthalmoscope. If we then whisk patients into the pre-surgical testing suite to measure their keratometry and topography, our data certainly will be unreliable. Furthermore, if we use this unreliable data to calculate the IOL power or plan a corneal astigmatism management procedure, we are setting ourselves up for a refractive surprise.

In fact, I was involved in a study that supports this assertion.¹ We recruited patients for the study based on tear osmolarity as determined by the TearLab Osmolarity System. We divided them into two groups, one with hyperosmolarity (>316 mOsm/L) in at least one eye, and the other with normal osmolarity (<308 mOsm/L) in both eyes. We measured K values in the enrolled eyes at baseline and then again within 3 weeks. We compared variability in average K values, vector analysis-calculated corneal astigmatism, and IOL sphere power calculations between the two groups.

In the hyperosmolar group, average K values varied by as much as 3.5D between the two visits, and one out of five patients exhibited a difference of 1D or greater. This resulted in a difference in IOL power calculations of greater than 0.5D in 10% of the patients. None of the patients in the normal osmolarity group demonstrated these differences between the two visits.

Potential Effects of OSD

The potential effects of OSD and a compromised tear film on pre-surgery measurements are apparent every day in my practice. In a recent patient, for example, it was easy to see the difference in the topography data obtained at the consultation versus the data obtained 2 weeks after OSD treatment (Figure 1).

This is also a good illustration of why it’s important for patients to discontinue their contact lenses for at least 2 weeks if they wear soft lenses. Whereas, they may need to leave them out 4 or more weeks if they wear RGP contact lenses prior to their pre-surgical measurements.

This patient came to me after having cataract surgery with another surgeon in our area. Although the surgery was flawless, she was unhappy with the end result. The patient, an emmetrope who wore one contact lens for reading, wasn’t asked to remove the lens until immediately prior to her biometry, keratometry, and topography measurements. Because the lens was somewhat dry and tight at the end of the day, a pseudo-astigmatic pattern was displayed and she unnecessarily received a toric IOL. After we optimized her ocular surface and repeated her measurements, it became clear that she did not need a toric IOL. I did an IOL exchange and replaced the toric with a monofocal lens. The patient was very satisfied with the outcome.

William Trattler, MD, has presented a similar case in which a patient was scheduled for a multifocal IOL (Figure 2). Had he based his IOL power calculation on measurements obtained prior to optimizing the ocular surface, he would have implanted a 20D lens. After optimization, the actual power needed was 21D, a full diopter different. Obviously, the patient would not have been happy had the ocular surface not been preemptively addressed.

In my mind, the importance of addressing the ocular surface couldn’t be clearer. If we diagnose ocular surface problems as part of the surgical consult and treat the problems before patients return for pre-surgical testing, we not only improve the accuracy of our measurements, but we achieve another benefit as well. Our patients feel less overwhelmed. They have more time to consider our educational information and their IOL options, and they may feel more empowered to choose an advanced technology implant.

The First Steps Can Be Small

To begin making the ocular surface a priority for producing excellent outcomes, a cataract or refractive surgeon can begin simply, by using fluorescein and lissamine green corneal stains at the slit lamp. Additional diagnostic tools can be added as the budget permits. In my practice, I rely on:

• modified OSDI and SPEED questionnaires that are incorporated into our EMR so screening technicians cannot bypass this critical step
• TearLab Osmolarity System
• MMP-9 testing with InflammaDry (Quidel)
• Meibomian gland imaging with LipiView (TearScience/Johnson & Johnson Vision)
• Doctor’s Allergy Formula diagnostic testing when warranted (Bausch + Lomb)
• topography and keratometry with the OPD-Scan III wavefront aberrometer (Nidek/Marco)
• corneal shape analysis with Cassini (i-Optics)
• Sjögren’s syndrome detection with Sjö (Bausch + Lomb), in recalcitrant cases.

As the adage goes, a picture is worth a thousand words. I find this to be quite true when it comes to showing patients the illustrative diagnostic imaging we obtain, such as warped placido discs and meibomian gland dropout.

Images help patients better understand that their OSD is preexisting, separate from their cataract, and will likely require a lifetime of treatment.

A New Era in Treatment

We’re fortunate today because once OSD is diagnosed, we have many applicable, effective therapies. I explain to patients that each person is different and OSD is a “stackable disease,” meaning we’ll stack one treatment on top of another until we reach the level where the eye is comfortable and the inflammation is controlled. Then we can proceed confidently with our pre-surgery measurements and surgery.

My treatment arsenal includes:

• several types of preservative-free artificial tears
• oral omega fatty acids supplementation (PRN and ScienceBased Health)
• heat eye compress/mask (Bruder and EyeGiene)
• vectored thermal pulsation with LipiFlow (TearScience/Johnson & Johnson Vision)
• intense pulsed light therapy (DermaMed Solutions and Lumenis)
• immunomodulation with cyclosporine (Restasis, Allergan) and lifitegrast (Xiidra, Shire)
• eyelid cleansers (Cliradex, Bio-Tissue; Zocuwipe, Zocular; Avenova, NovaBay; Blephadex, Lunovus)
• loteprednol etabonate (Lotemax Gel, Bausch + Lomb)
• tear neuro-stimulation with TrueTear (Allergan)
• amniotic cytokine extract drops (Genesis, Ocular Science)
• corneal rejuvenation with Prokera Slim cryopreserved amniotic membrane (Bio-Tissue)
• scleral cover shell.

In summary, evaluating and treating the ocular surface prior to obtaining pre-surgical measurements drives excellent outcomes and helps to minimize refractive surprises. As a result, happy patients become a practice’s ambassadors of good will. ■

Reference

1. Epitropoulos AT, Matossian C, Berdy GJ, Malhotra RP, Potvin R. Effect of tear osmolarity on repeatability of keratometry for cataract surgery planning. J Cataract Refract Surg. 2015;41(8):1672-1677.