Look for the condition and manage it prior to recommending patients proceed with a procedure
Patients who dislike their glasses or cannot comfortably wear contact lenses often seek consultation for surgical vision correction. Because I worked at a refractive surgery practice, I frequently meet with these patients. I start surgical consultations by asking what patients want from the procedure and why they are coming in now rather than 5 or 10 years ago. ODs who cannot deliver on patients’ desired outcomes just got an easier job. Before starting my examination, I tell all pre-surgical patients, “I am going to look for reasons to tell you not to do this procedure. If I can’t find any, we are good to go. If I find concerns, we will talk about what do about them and how they affect your candidacy for a vision correction procedure.”
I spent years at a referral center, and much of my time was spent trying to rehabilitate problematic eyes that had undergone surgical correction. Rarely, there was a surgical mishap such as a torn flap or a button hole. Sometimes the patient experienced diffuse lamellar keratitis and reduced best-corrected vision. Sometimes the patient was not a good candidate preoperatively. Many times, after the surgery, the patient suffered dry eye manifesting as blurred vision or pain.
I learned a lot from these consults over the years. Most importantly, I learned what to look for to avoid creating unhappy patients with keratorefractive surgery (KRS).
What to look for
One of my surgeons asked my psychiatrist husband about a secret button detector to identify patients who should not undergo laser in situ keratomileusis (LASIK), perhaps a scanner they could walk through or a checklist that would identify problematic patients. My husband delivered the bad news that it does not exist. However, signs to avoid surgery—such as ruling out dry eye disease and ocular pain concerns prior to surgery—do exist.
I advocate using a dry eye questionnaire to assess ocular comfort prior to procedure. If patients report ocular discomfort, ODs must be address this before proceeding with any type of surgery. However, patients with dry eye disease often fail to report concerns with comfort, redness, fatigue, or ocular pain because they perceive these conditions to be normal. ODs also must ask about these symptoms to prompt patients to discuss them further. Using a dry eye questionnaire helps with this.
ODs should know what medications patients are taking and whether they experience allergies. Are they taking more than 3 medications? The number of medications the patient is taking may indicate underlying systemic problems such as diabetes, autoimmune disease, and mental health concerns. Look for signs of chronic pain associated with, for example, fibromyalgia, amplified pain syndrome, or chronic inflammatory conditions.1 These conditions indicate a preexisting elevated chronic pain level that might be a concern after surgery. Patients who take more than 3 allergy medications may potentially have personality disorders; patients with allergies, asthma, and eczema have been associated with more mental health challenges.2
Upon ocular examination, critically, ODs must investigate anterior segment disease. Topography should reveal problems with irregular astigmatism. Consider corneal wavefront testing in addition to topography. Coma on aberrometry is pathological. It may be a manifestation of dry eye causing inferior steepening, or it may be ectasia.
Look for dry eye before surgery. Poor performance on a Schirmer test (<l10 mm) is a significant risk factor for dry eye.3 I recommend lissamine green and sodium fluorescein staining to identify ocular surface disease. Whereas sodium fluorescein identifies areas of desiccated or injured cells and where ocular surface damage has occurred,4 lissamine green stains devitalized cells. Sodium fluorescein is difficult to photograph, but lissamine green is easy to see on the bulbar and palpebral conjunctiva as well as lid margins.
Meibomian gland assessment is also critical before any surgical procedure, particularly LASIK, when patients will be checking their visual performance every 5 minutes. During biomicroscopy, assess the appearance of the lid margin to identify scurf, debris, scalloping, and neovascularization. Apply pressure to the lower lid margin to assess the level of gland inspissation and tenderness. Look for trichiasis, which indicates chronic lid inflammation.
Rule out other anterior segment disorders before surgery. These include allergic conjunctivitis, chalasis, epithelial basement membrane dystrophy, pingueculitis, soft lens-associated corneal hypoxia syndrome, pterygium, superior limbic keratoconjunctivitis, and other anterior segment problems. Identifying these conditions does not necessarily rule out KRS, but they need to be well controlled prior to surgery.
Dry eye after LASIK is a common problem.3 Etiologies may include goblet cell damage during surgery, changes in corneal curvature affecting wetting, decreased blink rates, medicamentosa from drops, corneal desensitization from contact lens wear, and severing of the corneal nerves during flap creation.5 Mean corneal sensation after LASIK in the ablated zone was reported to be lower than preoperative sensation.6
Managing the ocular surface
If ODs identify dry eye disease during the examination, they must address it before recommending corneal surgery. Frequent use of artificial tears is no longer the standard of care for these patients. The Dry Eye Workshop II report recommends treatment strategies based on type of dry eye and severity.7
After initiating treatment, monitoring patient adherence, and the length of time required to correct conditions such as superficial punctate keratitis, injection, or pingueculitis will determine whether the patient should proceed with KRS. If the condition is difficult to remediate, it may be best to avoid elective procedures because of persisting anterior segment disease. Combination treatments using immunomodulators such as cyclosporine (Restasis; Allergan, and Cequa; Sun Pharmaceutical) and lifitegrast (Xiidra; Novartis Pharmaceuticals), topical steroids, doxycycline, topical azithromycin, punctal plugs, hot compresses, and omega-3 fatty acid supplements may be required.
I typically see patients back 1 month after initiating treatment to reassess the anterior segment. I repeat topography and aberrometry to determine whether the treatment improved the clinical signs noted in the previous visit. If inferior steepening or coma was previously noted, I recheck to determine whether the conditions resolved with treatment. If the clinical signs improved easily in that time with 1 or 2 interventions, I am more likely to continue the discussion about surgical correction. If clinical signs failed to significantly improve, I relay this to the patientand put elective surgical procedures on hold while we continue treatment.
Assuming the clinical signs improved and the surgical discussion continued, what is the best treatment for patients with mild dry eye disease? LASIK, laser assisted subepithelial keratectomy (LASEK), epi-LASIK, small incision lenticule extraction (SMILE), and photorefractive keratectomy (PRK) may be considered for laser vision correction.
Some practitioners consider PRK to be the best choice relative to dry eye because PRK does not cut the nerves. However, Schallhorn et al performed a retrospective case series of 13, 319 patients who underwent LASIK or PRK. Dry eye symptoms at 3 months after surgery were more likely after PRK and in those with preoperative dry eye.8 Older age, female sex, and larger optical zones are associated with dry eye.9 SMILE has less impact on corneal nerves and induces less dry eye10,11 but cannot be enhanced.
Bottom line: Look for dry eye before KRS to ensure the patient is a good candidate.
1. Levitt AE, Galor A, Small L, Feuer W, Felix ER. Pain sensitivity and autonomic nervous system parameters as predictors of dry eye symptoms after LASIK. Ocul Surf. 2021;19:275-281. doi:10.1016/j.jtos.2020.10.004
2. Tzeng N-S, Chang H-A, Chung C-H, et al. Increased risk of psychiatric disorders in allergic diseases: a nationwide, population-based, cohort study. Front Psychiatry. 2018;9:133. doi:10.3389/ fpsyt.2018.00133
3. Yu EY, Leung A, Rao S, Lam DS. Effect of laser in situ keratomileusis on tear stability. Ophthalmology. 2000;107(12):2131-2135. doi:10.1016/s0161-6420(00)00388-2
4. Abelson MB, Ingerman A AI. The dye-namics of dry-eye diagnosis. Review of Ophthalmology. November 15, 2005. Accessed March 24, 2021. https://www.reviewofophthalmology. com/article/the-dye-namics-of-dry-eye-diagnosis#:~:text=The%20use%20of%20 diagnostic%20dyes,changes%20at%20the%20 cellular%20level
5. Dry eye: PRK or LASIK? Ophthalmology Times®. September 12, 2012. Accessed March 24, 2021. https://www.ophthalmologytimes.com/ view/dry-eye-prk-or-lasik
6. Lee HK, Lee KS, Kim HC, Lee SH, Kim EK. Nerve growth factor concentration and implications in photorefractive keratectomy vs laser in situ keratomileusis. Am J Ophthalmol. 2005;139(6):965-971. doi:10.1016/j. ajo.2004.12.051
7. Jones L, Downie LE, Korb D, et al. TFOS DEWS II management and therapy report. Ocul Surf. 2017;15(3):575-628. doi:10.1016/j. jtos.2017.05.006
8. Schallhorn JM, Pelouskova M, Oldenburg C, Teenan D, Hannan SJ, Schallhorn SC. Effect of gender and procedure on patient-reported dry eye symptoms after laser vision correction. J Refract Surg. 2019;35(3):161-168. doi:10.3928/108159 7X-20190107-01
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. Toda I. Dry eye after LASIK. Invest Ophthalmol Vis Sci. 2018;59(14):DES109-DES115. doi:10.1167/iovs.17-23538
11. 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. doi:10.1097/ ICO.000000000000099