Eyeworld

SEPTEMBER 2022 | EYEWORLD | 77 G treat that, we may theoretically have a better chance of helping outflow," he said. If there is inflammation on the surface of the eye, and the surgeon is planning to do a trabeculectomy or subconjunctival surgery, there is a greater likelihood of bleb failure. This is why it's important to address the ocular surface, whether by the of use SLT, drug delivery, or ear- ly MIGS to reduce medication burden. Dr. Singh added that prostaglandin ana- logs have been shown to affect the meibomian glands and cause gland dropout. It's not just the preservatives, it's the chemical in the glaucoma drops that can also cause significant destruction to the glands in the lids and conjunctiva. In addition to symptomology, there are certain tests that can identify dry eye in the office. For example, he said that one simple ad- dition is to use a Wratten filter on the slit lamp. This helps accentuate and highlight the ocular surface and tear film, he said. "Even if you use fluorescein, it's hard to see staining when you put a drop in because it's a high volume of drop. But if you use the Wratten filter, it will highlight the tear film more aggressively, and you can see staining and tear film breakup time better than just using cobalt blue light," Dr. Singh said. Dr. Wu, a cornea specialist, noted that he often sees limbal stem cell deficiency in his glau- coma patients, particularly those on multiple glaucoma medications. This can be caused by toxicity from the benzalkonium chloride (BAK) preservatives used in the glaucoma medications but can be seen in other ocular conditions and chronic contact lens wearers as well. Dr. Wu encourages his glaucoma patients to lubricate the ocular surface with preservative- free artificial tears as much as possible. "This is often hard for my glaucoma patients, as they are already on multiple drops for their glauco- ma," he said. "For my glaucoma patients with signs of limbal stem cell deficiency or ocular surface issues, I try to make sure they are on preservative-free formulations of their glaucoma medications. If the limbal stem cell deficiency is more advanced or if there are significant ocular surface issues, I often incorporate other treatments, such as autologous serum eye drops continued on page 78 Dry eye patient with and without the Wratten filter Source: Inder Paul Singh, MD

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