Dry eye and cataract
Treating dry eye disease before cataract surgery and minimising trauma to the ocular surface will optimise outcomes. Roibeard Ó hÉineacháin reports
Optimal dry eye management in cataract surgery candidates requires a well thought out strategy to treat the dry eye and protect the ocular surface from the potentially damaging effects of the cataract procedure, emphasises Prof Marc Labetoulle MD, Paris-Saclay University, Paris, France.
“To optimise outcomes in dry eye disease patients the first step is to make the correct diagnosis and adopt a surgical strategy prior to surgery followed by the use of optimised techniques during surgery and careful follow-up after surgery,” Prof Labetoulle told the 25th ESCRS Winter Meeting.
He noted that dry eye disease has been greatly underdiagnosed for many years in cataract surgery candidates. Research suggests that around half cataract surgery patients have clinically definitive meibomian gland dysfunction and 56% have meibomian gland atrophy. In addition, around 22% have a prior diagnosis of DED, and 60-to-70% of patients report ocular dryness.
The DED that occurs after cataract surgery is also often underdiagnosed. The procedure itself increases the frequency of DED. Some studies suggest dry eye occurs in around 10% of patients following uneventful cataract surgery, with increased staining in around 60%, and smaller increases in symptoms and Schirmer scores.
Prof Labetoulle noted that he and his associates have developed a testing strategy for dry eye, which their research shows can reduce the time required to diagnose or rule out DED to one minute in 95% of patients with no history of dry eye. The testing duration is five minutes in only 4%, and only 1% require a testing period longer than five minutes.
One important point is that the lachrymal hyperosmolarity characteristic of DED causes greater variability in biometric examinations. The significant variations in mean keratotomy and corneal astigmatism measurements can make the IOL calculation inaccurate, he said.
Regarding treatment strategies, Prof Labetoulle recommended that cataract surgery candidates with mild DED should continue with the same treatment for their condition as before. However, if they were not receiving dry eye treatment they should be prescribed one.
In patients with moderate DED, the treatment should be increased and followed to monitor improvements in their eyes’ condition. In addition, their surgery should be delayed one-to-two months with a last check before surgery. In eyes with severe DED, the treatment should be increased and surgery should be delayed by four-to-six months, again with a last check before surgery.
The DEWS II report suggests that treatment of mild dry eye should involve patient education and environmental and dietary modifications. In addition, drugs that reduce tear secretion should be withdrawn and patients should instead receive artificial eye drops, and adopt some eyelid hygiene practices, Prof Labetoulle said.
If the eye is unresponsive to these treatments or the DED is of a more moderate character, anti-inflammatory therapies should be introduced, including Omega 3 supplements and macrolides if needed to restore function to the meibomian gland. If the condition is very severe and insufficiently responsive to other measures, immunomodulators may be considered, along with more complex approaches such as autologous serum.
He noted that although immunomodulators like cyclosporine and lifitegrast are best reserved for the more extreme DED cases, numerous studies have demonstrated their efficacy in dry eye treatment. Tacrolimus has been approved as a treatment for severe allergies and there is some research suggesting it also may have promise as a treatment for dry eye.
DROPPING THE DROPS
Prof Labetoulle noted that much of the disturbance that cataract surgery inflicts on the ocular surface can be avoided in the weeks preoperatively by reducing the number of eyedrops patients receive and avoiding eye drops that contain benzalkonium chloride as well as antibiotic eyedrops, which provide no prophylaxis against endophthalmitis.
The use of Mydrane® (Théa) by intracameral injection can obviate the need for local anaesthetic drops or mydriatic drops during surgery. In addition, research shows that, compared to conventional eye drops, Mydrane induces less toxicity on the ocular surface and causes less epithelial alteration, allowing a faster recovery of the integrity of the ocular surface. As a result, patients have less frequent and milder eye symptoms.
Other measures that can be taken to avoid inducing or aggravating dry eye during cataract surgery include avoiding the use of aspirating speculums, limiting the light exposure during surgery, and limiting the thermal energy delivered by the phacoemulsification device. Regular wetting of the cornea and using the remaining hyaluronate on the cornea at the end of the surgery are also useful techniques.
Inflammation can influence postoperative results of cataract surgery and there is now research suggesting that postoperative administration of topical cyclosporine reduces symptoms and objective measures of dry eye following phacoemulsification. The research also suggests that even in cataract patients with no DED preoperatively, topical cyclosporine can improve postoperative corneal sensation and contrast discrimination.
“Ocular surface disease, most frequently dry eye disease, must be diagnosed and treated before the patient undergoes cataract surgery. There are multiple treatment options and ladder scale of therapy is available that can be adopted before during and after surgery,” Prof Labetoulle concluded.
Marc Labetoulle: firstname.lastname@example.org