Managing dry eye key to patient satisfaction after cataract, refractive surgeries

Dry-eye symptoms are a common postoperative complication after cataract and refractive surgery and can have an adverse impact on visual recovery and outcomes.¹

After LASIK surgery, common complaints (95% of patients) are of dry eye symptoms such as a gritty sensation, general ocular discomfort and fatigue, vision fluctuation, and ocular redness early in the postoperative period.²

Dry eye symptoms tend to lessen over time in LASIK patients, with 20% to 40% of patients still experiencing dry eye six months after surgery.²

Although usually transient, the postop symptoms can negatively impact perceived satisfaction with the surgery and overall quality of life.

The postoperative dry eye rate is less in cataract patients but still experienced by the majority. Upwards of 87% of cataract patients use artificial tears one month postop.³ The type of cataract surgery may also impact the severity of dry eye symptoms experienced.

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Increased risk

In 2015, Yu et al. reported that patients undergoing femtosecond laser-assisted cataract surgery were at a higher risk for staining and dry eye symptoms than patients undergoing conventional cataract surgery.⁴ The PHACO study re-emphasized that close to 20% of patients may not have a diagnosis of dry eye when presenting for cataract surgery, but do have clinical signs and that one diagnostic preop test may not be enough to rule out the diagnosis.{Trattler, 2017 #20627}

The type of intraocular lens (IOLs) selected can impact dry eye rates as well. Patients receiving multifocal

IOLs may be at particular risk of dry eye development, leading to IOL exchange in extreme cases.

Preoperative dry eye is also a potential cause of postoperative complications after pterygium surgery.⁵

Turkyilmaz et al. found that the presence of pterygium seems to cause dry eye, and although tear osmolarity signs improve after surgical removal of the pterygium, they deteriorate with recurrance.⁶

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Existing disease leads to worse outcomes
Many cataract and refractive surgery patients have undiagnosed dry eye. The PHACO study found the majority of patients screened for cataract surgery did not complain of dry eye symptoms, yet up to 80% showed conjunctival or corneal staining.¹

For physicians, this can present a challenge as cataract surgery can increase the severity of dry eye by about one level and LASIK will increase the severity by two levels.

Postoperative outcomes are also worse in patients with existing dry eye than in patients without.

For LASIK, existing dry eye will impact wavefront and topography readings, leading to residual refractive error.

In cataract surgery, dry eye will lead to inaccurate IOL calculations and axis and magnitude of astigmatism.

The American Academy of Ophthalmology now considers uncontrolled dry eye a contraindication for refractive surgery. It is therefore critical that clinicians evaluate the ocular surface and treat any disease before referring the patient to surgery.

Diagnostic tools include patient-reported symptom questionnaires such as SPEED and tests such as Schirmer’s, phenol red thread, tear break-up time, and ocular surface staining.

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Techniques to minimize dry eye severity
There are certain steps physicians can take to minimize the impact of dry eye during refractive surgery, including creating smaller, thinner flaps during LASIK will reduce the number of nerves cut.

The depth of laser ablation also impacts dry eye development. The deeper the ablation, the more likely the patient will develop dry eye. Hyperopic LASIK also increases the risk of dry eye development, due to the larger flap and treatment zone.

Although the data are inconclusive, some studies have found that the small incision lenticule extraction (SMILE) refractive procedure is less invasive than LASIK and reduces the incidence of postoperative dry eye because it is a flapless procedure. The vertical side cut to the cornea is shorter with

SMILE than femtosecond LASIK, which preserves the nerves.⁸

SMILE could be appropriate for contact lens wearers with dry eye who are not good candidates for LASIK or who are particularly concerned about exasperating dry eye effects postop.  

For cataract surgery patients, it is more about resolving any existing dry eye symptoms before proceeding with surgery. Patients with aqueous deficient dry eye should be prescribed Restasis (cyclosporine ophthalmic emulsion 0.05%) two to four weeks before cataract surgery. Physicians should see enough improvement to take accurate IOL calculations after that timeframe.

Patients with meibomian gland dysfunction (MGD) or blepharitis should use hot compresses, lid hygiene, and oral supplements such as flaxseed oil and fish oils to improve the health of their glands before proceeding with surgery. 

References:

1. Trattler WB, Majmudar PA, Donnenfeld ED, et al. The Prospective Health Assessment of Cataract Patients' Ocular Surface (PHACO) study: the effect of dry eye. Clin Ophthalmol. 2017;11:1423-30.
2. Shtein RM. Post-LASIK dry eye. Expert Rev Ophthalmol. 2011;6(5):575-82.
3. Roberts CW, Elie ER. Dry eye symptoms following cataract surgery. Insight 2007;32(1):14-21; quiz 2-3.
4. Yu Y, Chen X, Hua H, et al. Comparative outcomes of femtosecond laser-assisted cataract surgery and manual phacoemusification: a six-month follow-up. Clin Exp Ophthalmol. 2016;44(6):472-80.
5. Hovanesian JA. Pterygium: Techniques and Technologies for Surgical Success. Thorofare, NJ: Slack Inc., 2012.
6. Turkyilmaz K, Oner V, Sevim MS, et al. Effect of pterygium surgery on tear osmolarity. J Ophthalmol. 2013;2013:863498.
7. De Paiva CS, Chen Z, Koch DD, et al. The incidence and risk factors for developing dry eye after myopic LASIK. Am J Ophthalmol. 2006;141(3):438-45.
8. Kobashi H, Kamiya K, Shimizu K. Dry Eye After Small Incision Lenticule Extraction and Femtosecond Laser-Assisted LASIK: Meta-Analysis. Cornea 2017;36(1):85-91.