EyeWorld India March 2020 Issue

CORNEA 38 EWAP MARCH 2020 need for treatment; and corneal topography, which may reveal irregular astigmatism centrally. In any case, corneal irregularities must be “thoughtfully evaluated and treated when present in cataract patients,” wrote Dr. Kim and Dr. Goerlitz-Jessen. They cited a paper they published in the Journal of Cataract and Refractive Surgery , which highlights the impact that Salzmann’s nodules and EBMD in particular have on biometry, 1 “the foundation for successful visual outcomes in cataract surgery.” They suggest assessing cases using patient symptomatology, slit lamp examination, corneal topography, and biometry. While they agreed that “small, peripheral or astigmatically neutral corneal disease may not require intervention,” they noted that “it can be difficult to be confident with the degree to which potentially minor corneal changes may be impacting a patient’s optical system. If there is a reasonable concern that these lesions could affect a patient’s visual outcome, treatment is recommended. Certainly, patients with central disease, visual and ocular surface symptoms, corneal topographic changes, and/or biometric inconsistencies require intervention prior to cataract surgery.” Timing procedures Dr. Lee will always manage these conditions prior to cataract surgery. “If I see significant asymmetry between the topography in both eyes, and the eye with the corneal pathology has induced astigmatism, I will always remove the lesion prior to cataract surgery.” Lawrence Hirst, MD, whose practice focuses solely on pterygium removal, agrees. “If they cause irregular astigmatism, then they should be dealt with first before lens surgery,” he wrote in an email. The doctors suggest delaying cataract surgery by at least 30 days after the management corneal irregularities (ideally 90 days or more) to allow the cornea to stabilize. In any case, repeat measurements at several, separate time points are valuable to confirm the stability of corneal parameters prior to cataract surgery. “Giving the surface time to heal ensures the correct lens implantation power is used at the time of cataract removal,” wrote Dr. Lee. Premium IOLs As demonstrated by the case shared by Dr. Kim and Dr. Goerlitz-Jessen, premium IOLs such as toric IOLs “can absolutely be used” in cases with corneal abnormalities, provided the abnormalities are managed properly and the stability of the cornea is carefully assessed. EBMD, however, presents a particular challenge. “I would be worried about using a toric IOL if the EBMD is obvious and present in the visual axis,” wrote Dr. Lee. “If a superficial keratectomy is performed and the cornea appears clear and the topography shows regular corneal astigmatism, I would be more inclined to use a toric IOL.” “It is important to recognize that EBMD can both increase manifest astigmatism or also mask existing cylinder,” wrote Dr. Kim and Dr. Goerlitz-Jessen. “Also, EBMD often causes irregular patterns of astigmatism, which are poorly corrected with toric IOLs. If the corneal surface is not properly addressed prior to the use of a toric IOL, visual outcomes are unpredictable and patients are often unhappy. “If the ocular surface is optimized, a patient may become an excellent toric candidate and end up doing exceptionally well,” they continued. “However, it is also important to discuss the recurrence of EBMD with patients, which is seen in up to 13% of cases. 2 If EBMD recurs, the astigmatism correction from the toric IOL can be adversely affected, potentially requiring additional treatment to once again optimize the cornea and reap the benefits of their toric lens.” Superficial lamellar vs. PTK All the doctors agree that in most cases a superficial lamellar keratectomy is enough to manage lumps and bumps, reserving PTK for deeper, typically recurrent or refractory lesions that penetrate into the stroma. They caution that PTK, which may cut into the Bowman’s layer or even the stroma, has a greater risk of creating haze and/or scarring, Figure 1. Corneal topography of an eye with Salzmann’s nodules prior to superficial keratectomy (left) and 3 months after superficial keratectomy, prior to cataract surgery (right). Source: Terry Kim, MD, and Mark Goerlitz-Jessen, MD