CATARACT EWAP DECEMBER 2022 11 can use the retinal mapping features on OCT. It will pull up a picture for you and flag areas of atrophy as red. … The healthy areas are green,” Dr. Zhu said, adding that she prefers to scroll through every slice of the OCT herself to better localize defects. Dr. Charles said he does not advise using thickness maps or pseudo-color. “Review all black and white B-scan slices,” he said. “Do not import a technician-selected single image into EMR; use native imaging software.” 3. Look at more than one area. Dr. Zhu has her technicians print out the sheet with multiple slices for her review, so she doesn’t miss relevant pathology. “I think it’s important to capture as many slices as possible. Sometimes the surgeon doesn’t have time to sit there and scroll, so you’re relying on the technician to print out the best image for you, and some will print out that one view with the one slice of the fovea and you miss out on the other pathologies. Get the multi-grid view printed, if possible,” she said, adding that anything near the fovea will affect central quality of vision. Dr. Zhu said that patients with parafoveal epiretinal membranes on the outside of the macula or a scar just outside of the fovea could still be candidates for presbyopia-correcting IOLs in some cases. What to look for In general, Dr. Charles said cataract surgeons should be looking for macular degeneration, diabetic macular edema, central serous chorioretinopathy, epi- macular membranes, macular holes, and vitreomacular traction syndrome on OCT. He also said it’s important to assess the optic nerve for RNFL loss secondary to glaucoma. “Many macular disorders are invisible on retinal examination with the slit lamp and 90 diopter lens, Optos wide-angle imaging, [and] indirect ophthalmoscopy,” Dr. Charles said. Dr. Zhu said OCT can start picking up pathology in the vitreous. OCT can detect vitreous opacities, posterior vitreous detachment, or impending vitreous detachments. “You can diagnose that on OCT, depending on how the hyaloid face is attached. Sometimes it’s completely separated from the retina. If you see these thick vitreous opacities, that’s a sign that the vitreous might be turbid, and it may not give the best vision with a multifocal IOL,” she said. “The other thing is if you see an impending posterior vitreous detachment where the hyaloid is just detached at one part, but the other part is about to detach, you might want to counsel those patients about floaters postop because cataract surgery may induce them.” Dr. Zhu said this information is valuable for highly myopic eyes as well. If OCT shows the patient already had a PVD, their risk for retinal tears is lower. If the hyaloid face is still attached, cataract surgery could induce PVD, and they might be at higher risk for a postop retinal tear. “With highly myopic patients, I almost always send them to a retinal specialist for clearance before cataract surgery, just to make sure that we’re not missing any tears or holes in the periphery. Typically, if they have an axial length of greater than 25–26, I will send them for preop clearance. It’s not uncommon for the retinal specialist to find holes or severe lattice in the periphery that patients never knew about, and they laser them the same day,” Dr. Zhu said. At the macula, Dr. Zhu said she looks on OCT for epiretinal membranes, especially thick ones on top of the fovea that would be vision limiting, avoiding presbyopia-correcting lenses in these cases. She said she may even refer the patient to retina if she thinks their vision could be improved with treatment. In diabetics, she is looking for hard exudates and macular edema. If the patient has macular edema preop, she sends them to retina for anti- VEGF treatment before cataract surgery. She is also looking for AMD. A single drusen here and there might not impact vision, but confluent drusen throughout would signify the patient would not be a good candidate for a premium IOL and one who should be referred to retina. When looking at wet AMD, Dr. Zhu said there will be signs of intraretinal fluid, subretinal fluid, and/or the presence of choroidal neovascularization. “Those are patients you want to refer to retina right away, before cataract surgery, as they usually need an anti-VEGF injection because they can lose vision quickly. If the retina specialist can stabilize that part of the disease, they can have cataract surgery more safely,” she said. Other than that, Dr. Zhu said surgeons should be looking for scars from previous infection or trauma. Macular holes are another pathology that’s commonly seen. “Sometimes the patient will
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