DRY EYE disease (DED) should be on our diagnostic radars for surgical patients, as cataract and refractive surgery—and the medications used in the post-operative period — influence the integrity of the ocular surface and, therefore, can lead to or worsen existing DED. In many instances, patients link their ocular surface issues, and subsequent effects on vision, as a complication of surgery. Proper education and patient preparation is key to creating a successful patient experience.
Here, I explain how, specifically, cataract and refractive surgery affect the integrity of the ocular surface and the steps to manage DED before and after surgery.
EFFECT ON OCULAR SURFACE
Regarding cataract, DED after cataract surgery is multifactorial. In many instances, the patient population undergoing cataract surgery is already much more likely to have pre-existing ocular surface issues that will be compounded peri-operatively and post-operatively, due to their advanced age. Thus, it is essential to treat any underlying issues prior to referral for cataract surgery, if possible.
Factors that create or increase the incidence of DED in the immediate post-op period include reduced corneal sensitivity from either topical drugs or from corneal nerve transection, topical anesthesia drops during surgery and during post op and some other potential causes, such as the use of povidone iodine employed before surgery and the aspirating speculum used during surgery.
DED that develops days to weeks after surgery can stem from the elevation of inflammatory cytokines, goblet cell loss, meibomian gland dysfunction and hypersensitivity effects from preservatives, such as benzalkonium chloride (BAK), found in post-op medications.
Similarly, in corneal refractive surgery, studies show that DED post-operatively occurs from previously untreated DED, and it has been theorized that the alteration of the corneal nerves during surgery from creating the flap leads to a decrease in aqueous lacrimal deficiency, a drop in blink rate and more long-term challenges, including the activation of the inflammatory cascade, creating an increase in cytokines, which causes a disruption in both the corneal and conjunctival tissues. Further, many of the DED-related issues that cataract surgery patient’s experience, corneal refractive surgery patients experience as well.
Taking all these factors into account, it is important to treat patients appropriately both before and after surgery, so they can achieve potentially better visual outcomes. As mentioned, cataract patients tend to have DED prior to surgery. For this reason, follow this protocol prior to sending patients to the surgeon:
- Manage the condition. Should your assessment reveal DED, prescribe treatments to be used two to four weeks prior to surgery to ensure the condition will not interfere with the surgical outcome. When it comes to cataract surgery, in particular, DED can significantly alter the IOL calculations that need to be made for correct IOL selection.
Mild DED patients could benefit from preservative-free tears, while moderate to severe patients would benefit from steroid drops and FDA-approved DED prescription drops, such as cyclosporine ophthalmic emulsion 0.05% (Restasis, Allergan) or lifitegrast ophthalmic solution 5% (Xiidra, Shire).
- Continue treating post-operatively. During the post-operative period, keep having the patient use the DED treatments you prescribed before the surgery, again, to increase the likelihood of a positive outcome.
- Consider alternative anti-infection medications. At my practice, we perform “dropless” cataract surgery. This includes a formulation of preservative-free triamcinolone/moxifloxacin (“trimoxi”) that is injected after IOL implantation via the ciliary sulcus through the zonules. It eliminates the need for corneal tissue-altering antibiotics and steroid drops post-surgery, which can exacerbate/cause ocular dryness. The typical protocol of post-operative visits is one day, one week, one month and six months. At each visit, vision, IOP and the health of the corneal surface are assessed.
Treating patients post-operatively varies minimally from treating other patients who have DED. The typical post-operative protocol for cataract surgery is an antibiotic for one week, an NSAID drop for one month and a steroid drop for one week.
The common post-operative protocol for LASIK, the most popular refractive surgery performed in the United States, is an antibiotic for one week, steroid drop for 10 days and preservative-free artificial tears q.i.d. for at least a few months.
It is important to prescribe preservative-free forms of all three of these drops because, as mentioned above, BAK has a negative impact on the cornea.
Most studies show that DED symptoms and clinical findings, including corneal sensitivity, typically start to improve around three to six months post-operatively, when attended to.
HIGHER SUCCESS AFTER SURGERY
It is crucial to take all the above DED factors into account before referring for surgery. The surgeon may not evaluate the patient for DED prior to surgery, as he or she may think the patient is ready for the operation based on your referral.
Managing ocular dryness before surgery likely will create a more positive post-operative experience for the patient. It is just as important to continue DED management once the surgeon refers the patient back to you for post-operative care. OM