Published in Ocular Surface

Pre-Operative Optimization for Better Post-Operative Refractive Results

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15 min read

Learn how ophthalmologists can improve post-operative refractive results with pre-operative optimization of the ocular surface.

Pre-Operative Optimization for Better Post-Operative Refractive Results
It is widely understood that optimizing the ocular surface prior to refractive surgery is imperative to achieving the best results and patient satisfaction. Yet, decreased encounter times and increased workloads make it challenging to incorporate a full ocular surface workup into your appointment.
However, by integrating the latest in diagnostics and treatment and adopting a holistic philosophy, ophthalmologists can diagnose and manage dry eye disease (DED) and ocular surface issues in advance to better guarantee their patients superior outcomes.

The prevalence of dry eye in cataract patients

The most common ocular surface complaint is dry eye, which is becoming more and more pervasive due to current lifestyle and environmental factors, with digital device time playing a major role.
Dry eye is defined by Tear Film and Ocular Surface Society Dry Eye Workshop II (TFOS DEWS II) as “a multifactorial disease of the ocular surface characterized by a loss of homeostasis of the tear film, and accompanied by ocular symptoms, in which tear film instability and hyperosmolarity, ocular surface inflammation and damage, and neurosensory abnormalities play etiological roles.”1

Studies on the prevalence of dry eye in cataract patients

As with the general population, ocular surface disease is also widespread among those seeking cataract surgery.
A 2017 multi-center, observational study from Trattler et al. looked at 136 cataract patients aged 55 and older to evaluate for dry eye utilizing the International Task Force scale as well as a patient questionnaire, tear breakup time (TBUT), the ocular surface disease index score, conjunctival staining with lissamine green, and corneal staining with fluorescein.
Results showed that a TBUT ≤5 seconds was present in 62.9%, and a Schirmer’s score with anesthesia ≤5mm was shown in 18% of participants. In addition, positive corneal staining occurred in 77% of eyes.2
In a similar study, published by Gupta et al., 120 patients with an average age of 69.5 were evaluated for visually significant abnormal corneal surface examination, positive matrix metalloproteinase-9 (MMP-9) test, or abnormal osmolarity values. Clinical findings showed that 56.7% had abnormal osmolarity while 63.6% had abnormal MMM-9.
In addition, 39.2% demonstrated positive corneal staining. Out of 100 patients who filled out either the Ocular Surface Disease Index (OSDI) or Symptom Assessment iN Dry Eye questionnaire (SANDE), 54% reported symptoms that suggested ocular surface dysfunction. Most significantly, 80% of participants had at least one abnormal tear test result.3

In summary, this means 50 to 70% of patients presenting for cataract surgery can have signs of DED on clinical examination and testing.

Addressing elevated patient expectations

While ocular surface disease (OSD) has risen in prevalence in cataract patients, expectations have also increased—presenting a particular challenge. I now consider all cataract surgery as refractive cataract surgery.
Even individuals who are not receiving a multifocal intraocular lens (IOL) expect to be able to see without glasses, and those who are amenable to wearing spectacles for reading still expect glasses-free distance vision.
Knowing that ocular surface disease often leads to less than satisfactory surgical results, it is imperative to address it with every patient when they present for their pre-operative evaluation.

The connection between OSD and surgical success

Why is it so important that the ocular surface be optimized to ensure surgical success? To put it simply, the ocular surface is where the light comes in and reflects, meaning the tear film cornea interface is the first point of refraction. If the ocular surface is compromised, so is clear vision.
Additionally, ocular surface disease can impact and lead to inaccuracies in the various measurements required to properly select the correct IOL power. DED frequently causes warped readings in corneal topography, biometry, keratometry, and autorefraction, leading to post-operative refractive errors.
A study from Epitropoulous et al. revealed that astigmatism measurements and keratometry readings both had significant variability in patients with hyperosmolarity.4 The amount of refractive error was exacerbated when using extended depth of field, toric, or trifocal premium IOLs, which require an even greater level of accuracy.5 Inaccurate measurements can also alter the astigmatism, create more glare and halos, and contribute to seeing shadows.

Pearl: Trust your technician. If an ophthalmic technician reports that they are having a difficult time getting an accurate measurement, make certain to evaluate the ocular surface to see if dry eye is interfering.

Assessing cataract patients for OSD

To determine if a patient is suffering from ocular surface disease, communication is the first step. A dry eye questionnaire, such as the OSDI and Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire, can serve as a springboard for this conversation.
I have all new patients and patients returning for annual exams fill out the questionnaire while they are in the waiting room. During my initial meeting with the patient, I take time to address any findings from the questionnaire, complaints about irritation or compromised vision, and ask about significant lifestyle factors.
Lifestyle questions can be casually worked into our normal conversation. For example, I might simply say, “It’s chilly out there today. When you turned the heat on in your car, did you notice your eyes becoming irritated?”
Additionally, as many people spend up to 10 hours in front of a computer each day in Zoom meetings or doing near-work, it is necessary to establish their daily screen time. When engaging with a screen, blink rates are reduced, and eyes are held wide open, both of which contribute to DED.

The ugly price of beauty

False eyelashes are becoming a common culprit in meibomian gland dysfunction (MGD). The lashes and adhesives used to secure them to the lid cover the glands causing blockages, irritation, and allergic reactions, leading to insufficient tear production and a dried-out ocular surface. It is important to inform patients about the damaging effects cosmetic enhancements, like false lashes, can have.
After completing our conversation, I use my powers of observation to perform a brief ocular surface exam and note any obvious findings, such as redness, tearing, Demodex blepharitis, and superficial punctate keratitis. Next, I assess TBUT by adding fluorescein and asking the patient to blink; this simple procedure takes a mere 10 seconds per eye and reveals integral information.

3 tips for optimizing the ocular surface prior to cataract surgery

The importance of an optimized ocular surface is undeniable; by following this trio of tips, you can bolster your odds of surgical success.

1. Understand your dry eye treatment options.

For a long time, our dry eye treatment options were quite limited, with artificial tears and steroids being the first-line treatments.

Prescription therapies to manage DED

Then, Restasis (cyclosporine 0.05%)—indicated to increase tear production in patients whose tear production is presumed to be suppressed due to ocular inflammation associated with keratoconjunctivitis sicca—entered the picture.6
As it became more widely understood that inflammation was a major component in DED, other formulations became available, including Cequa (0.09% cyclosporine ophthalmic solution), which is designed to provide enhanced delivery to the ocular surface, and Xiidra, a lifitegrast molecule which inhibits the release of pro-inflammatory cytokines.7
In addition to these, we now have a broad range of treatments that address the multifaceted nature of ocular surface disease. One example is Miebo, which is a water and preservative-free, semifluorinated alkane indicated for dry eye disease. It has been shown in studies to be as, or more, effective than our actual meibum to prevent tear film evaporation.8
Touted as “the different cyclosporine,” in June of 2023, the FDA approved Vevye (Novaliq, cyclosporine 0.1%), which is a non-aqueous, non-preserved cyclosporine ophthalmic solution that is indicated for signs and symptoms of dry eye disease.9
As many patients, especially those who suffer from glaucoma, are hesitant to add one more drop to their daily regimen, it is very exciting to have Tyrvaya (varenicline solution) nasal spray, which is indicated for the treatment of the signs and symptoms of dry eye disease.
Tyrvaya is believed to increase endogenous tear film production via pharmacological neuroactivation of the trigeminal parasympathetic pathway (TPP), also known as the nasolacrimal reflex.10 Aside from saving the surface, I am a proponent of nasal spray because of its ease of use, especially for those with mobility issues, such as arthritis.

Adjunctive omega-3 supplementation to manage DED

In addition, I am an advocate of nutraceuticals containing omega-3 to supplement treatment. Inflammation occurs throughout the body, not just in the eye, so taking a holistic approach to ocular disease demands treatment from the inside out and not just the surface.
I feel very comfortable prescribing the research-based PRN Omega 3 products because they are made with re-esterified triglyceride (rTG), which is absorbed by the body three times better than store-bought fish oil.11 Moreover, PRN Product Advisors provide ongoing support, removing a burden on my staff.

2. Deal with Demodex.

In the initial evaluation, I make certain the eyelashes are clean of excess oil and Demodex mites. Top tools for identifying infestation include slit lamp examination to identify cylindrical dandruff, lid examination, epilation of lashes to discern mites under microscopic examination, and patient symptomatology.
When I see a proliferation of Demodex, I prescribe a single round of Xdemvy (lotilaner ophthalmic solution 0.25%, Tarsus Pharmaceuticals) to be used for 6 to 8 weeks prior to surgery. For many patients, we perform a pre-operative BlephEx treatment to clean the eyelids of excess biofilm, bacteria, and bacterial toxins.
Intense pulsed light therapy (IPL), which delivers high-intensity polychromatic light to the target tissue, has been shown to decrease bacteria and inflammation and is demodicidal (causing mite death via coagulative necrosis) as well as being beneficial in the treatment of MGD.12,13

3. Prescribe preservative-free drops.

Fundamentally, any preservative is the enemy of the ocular surface. Though effective as an antimicrobial agent, the most common of these, benzalkonium chloride (BAK), can wreak havoc by decreasing tear film stability while increasing inflammation. This often leads to the symptoms—stinging, burning, redness, and decreased vision—that are synonymous with dry eye disease.14
Other preservatives, including polyquaternium, thimerosal, and chlorhexidine, may lead to similar toxic effects. Epithelial cell loss is an even more serious consequence of long-term preservative use.15
Luckily, many manufacturers are addressing this issue by making preservative-free formulations of many medications available. There are several studies that support the benefits of prescribing preservative free, especially in glaucoma patients who often possess the lion’s share of the topical medication burden.16

Switching to preservative-free glaucoma medications

I advise switching to preservative-free prostaglandin analogs, which have been shown to improve tear film stability, decrease corneal staining, and reduce ocular discomfort while still effectively managing the intraocular pressure.17
Timoptic in Ocudose (timolol maleate ophthalmic solution 0.25% and 0.5%) is preservative free. For patients who do not tolerate a beta blocker, Théa provides a portfolio of preservative-free glaucoma medications, including two prostaglandins Iyuzeh (latanoparost 0.005%) and Zioptan (tafluprost 0.0015%), and preservative-free COSOPT PF (dorzolamide hydrochloride-timolol maleate ophthalmic solution) 2%/0.5%.
As of 2020, there is also an FDA-approved implantable option for intraocular pressure (IOP) reduction. In clinical studies, Durysta, a preservative-free bimatoprost intracameral implant (10mcg, Allergan, An AbbVie Company), reduced eye pressure in people with open-angle glaucoma or high eye pressure (ocular hypertension) for up to 15 weeks.18

Avoiding post-operative dry eye

Implantables, such as Dexycu (dexamethasone intraocular suspension 9%, EyePoint Pharmaceuticals) and Dextenza (dexamethasone ophthalmic insert 0.4mg, Ocular Therapeutix), are also changing the landscape for the better by reducing or eliminating the need for eye drops, post-operatively.
Dextenza greatly reduces the risk of post-operative dry eye. Placed in the lower lacrimal punctum, Dextenza, a dexamethasone implant, not only delivers preservative-free, sustained steroid coverage for up to 30 days to address post-surgical pain and inflammation, but also serves as a punctal plug for the month following surgery, which may increase ocular surface lubrication.

Success is measured by sight

As surgeons, we are prone to focus primarily on technical proficiency and our performance in the operating suite, while losing sight of the bigger picture, including the crucial role of the tear film corneal interface.
Though we want to utilize all of the latest surgical innovations, it is essential to stay abreast of the newest research and treatments for the ocular surface as well.  The ultimate goal is to enhance vision—and, subsequently, the quality of life—of the patient.
Therefore, it is up to us to use all of the diagnostic and treatment tools in our armamentarium to get each patient as close as possible to a healthy and happy 20/20.
  1. Craig JP, Nichols KK, Akpek EK, et al. TFOS DEWS II Definition and Classification Report. Ocul Surf. 2017;15(3):276-283.
  2. 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 Aug 7;11:1423-1430. doi: 10.2147/OPTH.S120159. PMID: 28848324; PMCID: PMC5557104.
  3. Gupta PK, Drinkwater OJ, VanDusen KW, et al. Prevalence of ocular surface dysfunction in patients presenting for cataract surgery evaluation. J Cataract Refract Surg. 2018;44(9):1090-1096.
  4. Epitropoulos AT, Matossian C, Berdy GJ, et al. Effect of tear osmolarity on repeatability of keratometry for cataract surgery planning. J Cataract Refract Surg. 2015;41(8).
  5. Hillman l. Premium IOLs in imperfect eyes. ASCRS Eyeworld. Published December 2021.
  6. Restasis Prescribing Information. AbbVie. Updated May 2010.
  7. Minhas H. Cequa, Restasis, and Xiidra Reviews: Medications for Dry Eye Disease. Eyes On Eyecare. Published July 1, 2021.
  8. Sheppard JD, Evans DG, Protzko EE. A review of the first anti-evaporative prescription treatment for dry eye disease: perfluorohexyloctane ophthalmic solution. Am J Manag Care. 2023 Nov;29(14 Suppl):S251-S259. doi: 10.37765/ajmc.2023.89464. PMID: 37930231.
  9. Novaliq Announces FDA Approval of VEVYE™ (Cyclosporine Ophthalmic Solution) 0.1%, for the Treatment of the Signs and Symptoms of Dry Eye Disease. Novaliq. Published June 8, 2023.
  10. Frampton JE. Varenicline Solution Nasal Spray: A Review in Dry Eye Disease. Drugs. 2022 Sep;82(14):1481-1488. doi: 10.1007/s40265-022-01782-4. Epub 2022 Oct 5. PMID: 36197638; PMCID: PMC9533262.
  11. Visioli F, Risé P, Barassi MC, et al. Dietary intake of fish vs. formulations leads to higher plasma concentrations of n-3 fatty acids. Lipids. 2003;38:415-8
  12. Fishman HA, Periman LM, Shah AA. Real-Time Video Microscopy of In Vitro Demodex Death by Intense Pulsed Light. Photobiomodul Photomed Laser Surg. 2020 Aug;38(8):472-476.
  13. Dell SJ. Intense pulsed light for evaporative dry eye disease. Clin Ophthalmol. 2017 Jun 20;11:1167-1173.
  14. Walsh K, Jones L. The use of preservatives in dry eye drops. Clin Ophthalmol. 2019 Aug 1;13:1409-1425. doi: 10.2147/OPTH.S211611.
  15. Baudouin C, Labbé A, Liang H, et al. Preservatives in eyedrops: the good, the bad and the ugly. Prog Retin Eye Res. 2010 Ju;29(4):312-334. doi: 10.1016/j.preteyeres.2010.03.001.
  16. Thygesen J. Glaucoma therapy: preservative-free for all? Clin Ophthalmol. 2018 Apr 13;12:707-717. doi: 10.2147/OPTH.S150816. PMID: 29713138.
  17. Stalmans I, Mégevand GS, Cordeiro MF, et al. Preservative-free treatment in glaucoma: who, when, and why? Eur J Ophthalmol. 2013 Jul-Aug;23(4):518-525. doi: 10.5301/ejo.5000270. Epub 2013 Mar 7. PMID: 23483513.
  18. Sheybani A, Smith T, Bacharach J, et al. Understanding the safety & efficacy of DURYSTA (bimatoprost intracameral implant). Glaucoma Today. Published November/December 2020.
Renee Bovelle, MD, FAAO
About Renee Bovelle, MD, FAAO

Dr. Renee Bovelle, the founder and CEO of Advanced Eyecare Medical Center, PA “dba” Envision Eye & Laser Center, was trained at Wellesley College, David Geffen UCLA School of Medicine, Yale University, and the Louisiana State University Eye Center. She was pleased to be named a Washingtonian Top Doctor by her peers. 

Additionally, Dr. Bovelle received a Master’s in Cybersecurity Strategy and Information Management from George Washington University and focused on policies and practices that protect critical information with particular attention to the healthcare field.

She is the Cornea Director at Howard University Hospital and holds academic appointments at Ross University School of Medicine and the University of Maryland Capital Region Medical Center.

Renee Bovelle, MD, FAAO
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