Dry eye after LASIK is a common problem

With these surgically-induced DED factors in consideration, it is critical that practitioners need to identify patients at risk for severe post-LASIK DED prior to recommendation of surgery. (Adobe Stock / ChayTee)

Since the initial days of laser in situ keratomileusis (LASIK), dry eye syndrome has been a widely known postoperative complication. Post-LASIK dry eye disease (DED) usually peaks in the first few weeks to months after surgery, and vastly improves anywhere from 6 to 12 months following surgery. Symptoms can vary from mild to debilitating. Recognition of predisposing dry eye factors, examination, and counseling help prepare patients for postoperative symptoms. This article will outline the best practices for assessing and managing post-LASIK DED to improve patient surgical outcomes and expectations.

Literature reports that, following LASIK, 95% of patients have symptoms of DED immediately, 60% have symptoms 1 month later, and 10% to 40% have symptoms that last 6 months or longer.¹ With these statistics, refractive surgeons recognize that post-LASIK DED requires a significant amount of hand-holding and increased chair time, adds to patient stress, and affects visual recovery. Often, these patients fall into the laps of the optometrist, the co–managing doctor. Being well equipped and aware will benefit doctor and patient.

Understanding post-LASIK DED

What is the etiology of iatrogenic post-LASIK DED? The cause remains widely unknown. Is the dryness due to severing corneal nerves, secondary to laser corneal reshaping, or consequential to high pressure causing conjunctival goblet cell damage during suction? Is inadequate blink rate the reason? Is the dryness secondary to postoperative medicamentosa? Or a combination of the above?

Corneal denervation is proposed as the main culprit for postoperative dry eye following LASIK. Iatrogenic severing of both stromal corneal nerves and the subbasal nerve plexus during flap creation and excimer laser ablation triggers dry eye and the resulting symptoms.² Some studies have shown that strictly surface ablation procedures without flap creation, like laser-assisted subepithelial keratectomy (LASEK), epi-LASIK, small incision lenticule extraction, and photorefractive keratectomy do not cause dry eye that lasts as long.³ These alternative methods should be considered for those predisposed to DED.

Loss of corneal sensitivity secondary to severed corneal nerves propagates the cycle of DED, resulting in decreased lacrimal gland stimulation, decreased aqueous tear secretion, decreased blink rate, insufficient basal and reflex tearing, and in extreme cases LASIK-induced neurotrophic epitheliopathy.⁴ This cascade continues to trigger dry eye symptoms until corneal nerve regeneration occurs, which takes weeks to months and often never fully returns to baseline. Higher refractive errors and larger optical zones require deeper ablation of the corneal tissue, which can further damage corneal nerves and corneal sensitivity.⁵

Manipulation of the corneal thickness and corneal reshaping further affects the anatomical relationship between the ocular surface and eyelid. In general, higher refractive errors and hyperopic LASIK patients withstand larger structural changes. This modified ocular surface creates decreased lipid release from the meibomian glands, which results in abnormal tear distribution and increased tear film evaporation.6 With this tear film instability, patients will experience fluctuation in vision, not because of LASIK but secondary to postsurgical dry eye.

Medicamentosa, commonly caused by postoperative antibiotics and nonsteroidal anti-inflammatory drops, can additionally be toxic to the epithelium, along with the preservatives. These topical eye drops may induce keratitis and initiate irritative symptoms. Preservative-free artificial tears are strongly recommended after LASIK to minimize corneal toxicity with frequent tear application.⁷

Finally, direct damage to goblet cells from the suction device during creation of the LASIK flap, via both the microkeratome and femtosecond laser-created flaps, compromises the mucin layer of the tear film.^8,9 Mucins play a key role in tear film stability. Changes in the mucin layer may lead to enhanced tear evaporation contributing to increased tear osmolarity and corresponding ocular surface inflammation.

With these surgically-induced DED factors in consideration, it is critical that practitioners need to identify patients at risk for severe post-LASIK DED prior to recommendation of surgery. The overall prevalence of dry eye symptoms prior to undergoing LASIK is estimated to be between 38% and 75%.⁷ Common predisposing factors for DED include gender (female>male), Asian ethnicity, contact lens use, eyelid anomalies, high refractive error, specific medications, diabetes, autoimmune disease (eg, Sjögren syndrome, lupus, rheumatoid arthritis), chronic pain (eg, fibromyalgia), immunodeficiency disease (eg, AIDS), and chronic inflammatory conditions.

Utilizing a dry eye questionnaire and obtaining accurate histories can help practitioners detect DED prior to consultation. Dry eye questionnaires that assess the effect of health-related quality of life help provide a balanced approach and quantitative evaluation of subjective symptoms.¹⁰ Evaluating a patient’s lifestyle and list of medications (eg, isotretinoin use) can further filter candidates. Patients who are pregnant or breastfeeding and undergoing hormonal dry eye are also contraindications for refractive surgery.

The combined subjective questionnaire and objective clinical findings guide the proper treatment. Inspection on slit lamp examination should include the following: tear breakup time, tear lake, tear meniscus height, and corneal staining. Rose bengal or lissamine green can be utilized to stain devitalized epithelial cells, along with the more commonly used fluorescein sodium staining. Other objective test measures that can help detect dry eye syndrome include Schirmer strips to measure basic and reflex tearing, TearLab (Trukera Medical) to measure tear osmolarity levels, and InflammaDry (Quidel) to measure MMP9 levels. Careful evaluation of the lid margin helps to identify underlying meibomian gland dysfunction (MGD), ocular rosacea, and blepharitis.

Assessing symptoms such as complaints of dryness, grittiness, foreign body sensation, excessive tearing, ocular fatigue, intermittent blurry vision, visual fluctuations, irritation, or tired eyes should be considered. Burning and stinging sensation are often the most common of all DED symptoms. Assessing the patient’s digital screen time; exposure to wind, heat, and low humidity; and day-to-day activities can also indicate whether post-LASIK dryness will be a concern.

Managing dry eye in this patient population

How best to manage dry eye in these patients? First-line treatment has always been simply to utilize OTC lubricating drops. Preservative-free drops are preferred to reduce ocular surface medicamentosa.¹¹ If OTC topical drops prove ineffective, switching to a medicated dry eye therapy may be necessary. Tools in this category include cyclosporine (Restasis; Allergan), lifitegrast (Xiidra; Bausch + Lomb), varenicline (Tyrvaya; Oyster Point), autologous serum eye drops, topical steroids, doxycycline, topical azithromycin, hypochlorous acid, and nutraceuticals such as oral ω-3 supplements.

more severe and prolonged post-LASIK DED, punctal plugs (temporary collagen punctal plugs or permanent silicone punctal plugs) can be inserted; scleral contact lenses can be fit for hydration; and heat treatments such as MiBo (MiBo Medical Group), OCuSOFT Thermal 1-Touch (OCuSOFT), LipiFlow (Johnson & Johnson Vision), iLux (Alcon), and/or TearCare (Sight Sciences) can be recommended. Intense pulsed light and thermal pulsation reduce inflammation and offer MGD relief. Amniotic stem cell therapy or nerve growth factor such as cenegermin (Oxervate; Dompe) can be initiated for patients with extreme dry eye. Blinking exercises benefit all patients following LASIK and should be assigned along with hot compresses, lid scrubs, and nighttime ointment 1 month after surgery.

Identifying patients at risk for severe post-LASIK DED is crucial to enhancing comfort, stabilizing vision, and optimizing surgical outcomes. In time, with improved understanding of iatrogenically induced post-LASIK DED, better tools and treatments will emerge. Until then, patients should be appropriately counseled with realistic postoperative expectations.

References

1. Shtein RM. Post-LASIK dry eye. Expert Rev Ophthalmol. 2011;6(5):575-582. doi:10.1586/eop.11.56

2. Bandeira F, Yusoff NZ, Yam GH, Mehta JS. Corneal re-innervation following refractive surgery treatments. Neural Regen Res. 2019;14(4):557-565. doi:10.4103/1673-5374.247421

3. Kuryan J, Cheema A, Chuck RS. Laser-assisted subepithelial keratectomy (LASEK) versus laser-assisted in-situ keratomileusis (LASIK) for correcting myopia. Cochrane Database Syst Rev. 2017;2(2):CD011080. doi:10.1002/14651858.CD011080.pub2

4. Ambrósio R Jr, Tervo T, Wilson SE. LASIK-associated dry eye and neurotrophic epitheliopathy: pathophysiology and strategies for prevention and treatment. J Refract Surg. 2008;24(4):396-407. doi:10.3928/1081597X-20080401-14

5. Turu L, Alexandrescu C, Stana D, Tudosescu R. Dry eye disease after LASIK. J Med Life. 2012;5(1):82-84.

6. Gurnani B, Kaur K. Meibomian gland disease. In: StatPearls [Internet]. StatPearls Publishing; 2023.

7. Ribeiro MVMR, Barbosa FT, Ribeiro LEF, Sousa-Rodrigues CF, Ribeiro EAN. Effectiveness of using preservative-free artificial tears versus preserved lubricants for the treatment of dry eyes: a systematic review. Arq Bras Oftalmol. 2019;82(5):436-445. doi:10.5935/0004-2749.20190097

8. Rodriguez AE, Rodriguez-Prats JL, Hamdi IM, Galal A, Awadalla M, Alio JL. Comparison of goblet cell density after femtosecond laser and mechanical microkeratome in LASIK. Invest Ophthalmol Vis Sci. 2007;48(6):2570-2575. doi:10.1167/iovs.06-1259

9. Shehadeh-Mashor R, Mimouni M, Shapira Y, Sela T, Munzer G, Kaiserman I. Risk factors for dry eye after refractive surgery. Cornea. 2019;38(12):1495-1499. doi:10.1097/ICO.0000000000002152

10. Okumura Y, Inomata T, Iwata N, et al. A review of dry eye questionnaires: measuring patient-reported outcomes and health-related quality of life. Diagnostics (Basel). 2020;10(8):559. doi:10.3390/diagnostics10080559

11. Kahook MY. The pros and cons of preservatives. Rev Ophthalmol. Published online April 15, 2015. Accessed March 17, 2021. https://www.reviewofophthalmology.com/article/the-pros-and-cons-of-preservatives