How can ophthalmologists predict or prevent dry eye after cataract surgery?
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Welcome to another edition of CEDARS/ASPENS Debates. CEDARS/ASPENS is a society of cornea, cataract and refractive surgery specialists, here to discuss some of the latest hot topics in ophthalmology.
This month we are going to discuss dry eye disease (DED) around cataract surgery, a topic that has gained increasing momentum since the introduction of premium IOLs. Ophthalmologists are now well aware of the need to diagnose and treat DED before surgery, but postoperative symptomatic dry eye may occur despite preoperative treatment or even in patients who had not previously screened positively for DED. How can we predict and try to prevent postoperative symptomatic dry eye? Tal Raviv, MD, and Ranjan P. Malhotra, MD, FACS, will dig into the topic and tell us what they have learned from their experience.
Kenneth A. Beckman, MD, FACS
OSN CEDARS/ASPENS Debates Editor
When there are clear symptoms of ocular discomfort
Dry eye disease is a multifaceted condition that can manifest after cataract surgery in many ways.
But from a high-level perspective, postop dry eye can be framed into two camps: patients with visual dissatisfaction and patients with ocular discomfort. In my experience, we are good at screening and optimizing the visually significant type of dry eye but still have a challenge in predicting who will present with postop ocular discomfort, foreign body sensation or pain.
All of us have patients who complain of post-surgical foreign body sensation whose corneas look healthy and who did not screen positively for dry eye before surgery. Many of these symptoms abate, but some persist for months.
A recent meta-analysis by Miura and colleagues found that 37.4% of patients without preexisting dry eye disease (DED) developed DED after cataract surgery. Another study by Sajnani and colleagues found that 34% of patients had persistent dry eye symptoms 6 months after cataract surgery.
Our current DED screening tests are meant to uncover visually significant dry eye. This is critical to achieve excellent visual outcomes. The ASCRS Preoperative OSD Algorithm helps us identify visually significant dry eye. We can then treat, optimize and counsel these patients. We may also choose a monofocal IOL over a diffractive multifocal in these higher-risk patients.
But how can we screen for the one in three patients who may get new-onset DED symptoms with little to no preop DED signs or symptoms? Sajnani found certain preop factors were highly associated with developing postop dry eye pain 6 months after surgery, including non-ocular chronic pain disorder, antihistamine use, antidepressant use, anxiolytic use, anti-insomnia medication use and autoimmune disorder.
There may be surgical factors as well. Cho and Kim found that a temporal grooved incision induced significantly more symptomatic DED foreign body sensation than a single-plane incision in non-dry eye patients.
We are starting to understand that post-cataract pain syndromes are similar to other persistent post-surgical pain that has been described in specialties such as coronary artery bypass surgery, inguinal hernia repair and dental implant surgery.
In addition to the traditional dry eye questionnaires and diagnostics, I have begun to more carefully screen patients’ medication lists. In higher-risk patients on multiple anxiolytics or sleeping medications or with an autoimmune disorder, I will discuss their increased risk for postop pain. I will also recommend longer preop and postop topical treatment with a steroid and NSAID. There is evidence that early postop pain is a risk factor for more chronic pain, so I am quick to place a bandage contact lens or initiate more aggressive ocular surface therapy if there is early postop pain in these patients.
For treatment of astigmatism, I utilize toric IOLs whenever possible, and when treating low astigmatism, I favor intrastromal femtosecond arcuates over anterior penetrating arcuates to minimize corneal nerve and epithelial disruption as much as possible.
Postop DED pain is frustrating for patients and surgeons alike, especially because it can arise in asymptomatic non-dry eye patients. We have a better understanding of this neuropathic pain condition, and fortunately, it usually self-resolves. For the rare recalcitrant chronic corneal pain patients, I have had success with serum tears, bandage contact lenses, anterior stromal puncture by the corneal wound, amnionic membrane and even referral to pain specialists for centrally acting neuropathic pain medications such as duloxetine and others.
- For more information:
- Tal Raviv, MD, of Eye Center of New York, can be reached at info@EyeCenterofNY.com.
When visual disturbances are the only symptom
More commonly than not, as we examine patients who are coming in for surgery, we see signs of dry eye disease: high osmolarity, superficial punctate keratitis or a dry, chapped corneal surface.
When we tell patients that they have dry eye, quite often they state they do not feel any of the typical symptoms such as foreign body sensation, irritation, burning or stinging. However, even in absence of any perceived discomfort, a high tear osmolarity or the alterations that we see on our clinical exams are affecting the patient’s vision. In the affected patients, I often tell them that about 70% of their decreased vision is from cataract while the remaining 30% is actually from their dry eye. Knowing that analogies work well with the majority of the population, I explain that the ocular surface is like a car windshield, and the effect of a high osmolarity is similar to having a lot of salt on that windshield. When you turn on the windshield wipers, the salt will streak the windshield. Similarly, in the eye, there can be streaks in their vision. Many times, patients do not feel the salt or the dry spots. In these patients, the only symptoms of their DED are the visual symptoms.
What I tell patients is that dry eye disease is a condition in which the symptoms do not always correlate with signs. Quite often, there is a disconnect. The PHACO study showed that 77% of patients who come for cataract surgery had positive corneal staining, with 50% having positive central corneal staining. Despite this, 60% never reported complaints of foreign body sensation, and only 13% complained of foreign body sensation half or most of the time. Therefore, we should all make a habit of looking for signs of dry eye in our cataract patients, as well as refractive cataract surgery patients. A good dry eye exam checklist includes visual inspection of the corneal surface (especially for superficial punctate keratitis), tear breakup times, staining of the ocular surface using fluorescein or lissamine green, and measuring tear osmolarity.
Some patients may experience new dry eye symptoms after surgery. This is quite often a transient effect of no longer using glasses or contact lenses and having the eyes more exposed to the air. But in some cases, it might be an exacerbation of their preoperative dry eye issues, particularly if they have not been using their drops regularly. As physicians, it is important to go back to the fact that they had this before so that they do not blame the lens or the surgery. Of course, visual symptoms after surgery may also be caused by residual refractive error. If patients have the expectation that their prescription is going to be 0 D, I tell them before surgery that IOLs come in certain sizes, and we cannot always get the in-between sizes. Going back to my trusted analogies, I describe IOL strengths like shoe sizes, in which half sizes are not always available. If your foot is a 7.25 shoe size, you have to choose either a 7 or 7.5. Patients understand this analogy quickly and remember it. I assure them I will get them a prescription as close to 0 D as I can, but if there is a little prescription left, they will have to wear some glasses after surgery to fine-tune vision when they are driving at night. Dry eye and residual refractive error are the two most common causes of mild decreased vision after surgery. However, fluctuating vision that is better at times and worse at others is most likely a problem of the ocular surface.
For both preoperative and postoperative dry eye, in addition to sodium hyaluronate-containing acid eye drops, there are some good prescription products that help lower the osmolarity, such as Xiidra (lifitegrast ophthalmic solution, Bausch + Lomb), or drops that stop evaporation, such as Miebo (perfluorohexyloctane ophthalmic solution, Bausch + Lomb). There is also a 0.1% cyclosporine-based product, Vevye (Harrow). These products, alone or in combination, will help prevent and/or manage dry eye disease symptoms, including blurry vision.
In summary, the key to managing the potential visual components to dry eye disease post-surgery is identification and treatment prior to surgery. Making patients aware of their DED and the potential exacerbation of this after surgery due to exposure, decreased blink or stoppage of pre-treatment DED therapy once surgery is completed will help to manage patient expectations and ensure a positive outcome for both patient and surgeon.
- For more information:
- Ranjan P. Malhotra, MD, FACS, of Ophthalmology Associates in St. Louis, can be reached at ranjan'malhotramd@gmail.com.
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