12 EyeWorld Asia Pacific | June 2024 Therefore, I do measurements with both partial coherence interferometry (IOLMaster, Carl Zeiss Meditec) and optical low coherence reflectometry (Lenstar, Haag-Streit). This allows me to cross check the measurements for accuracy. I would also consider doing a UBM to measure scleral thickness, as we know that is a risk factor for choroidal effusions and possible malignant glaucoma following surgery.” If the axial length is <18 mm or the sclera appears thickened and Dr. Bedrood notices a uveal effusion (high IOP and shallowing of chamber at the time of surgery), she said she anticipates the possibility of scleral windows. Dr. Bedrood said that a short eye might leave patients at a slightly higher risk for postoperative complications like iris prolapse, corneal edema, malignant glaucoma, and CME. Dr. Giaconi said that she will let patients know that a short eye tends to have crowded anatomy and that it is at higher risk for certain complications, like iris prolapse, which can lead to transillumination defects postoperatively. It can also be more difficult to remove the lens, and therefore, there is a higher risk for corneal edema. “Predicting where the lens implant will end up in the eye is also more difficult, so hitting the refractive target is less certain,” she said. Dr. Bedrood agreed that lens calculations may be different with these short eyes. “I make the patient aware that the lens calculations are made based on formulas that consider the dimensions of the eye,” Dr. Bedrood said. “Since the dimensions of their eyes fall in an ‘abnormal’ range, then we have some limitations with the formulas and a possibility of postoperative refractive error is possible. Over the last few years, however, we have had newer lens formulas developed to help reduce the chance of refractive error.” Dr. Giaconi recommends newer IOL calculation formulas. “There are some studies showing the Kane formula as promising for short axial lengths,” she said. “I like the new [ESCRS] IOL calculator which shows multiple formulas of the newest generation and allows me to compare multiple formulas.” Dr. Bedrood said that, in the past, the formulas that were suggested for use in short axial length eyes were the Haigis and Hoffer Q formulas. “There are newer formulas that we now implement into our practice,” she said, adding that the K6 formula and the Kane formula are multivariate formulas that have shown good success for obtaining targeted refractive outcomes in the shorter eyes.1 Short eyes are more difficult to operate in, Dr. Giaconi said. There can be more positive posterior pressure; the anterior chamber is often shallow; the capsulorhexis can have a tendency to run out; and iris prolapse is more common, which can lead to iris damage. “For shorter eyes, I will administer IV Mannitol about an hour before surgery (20 grams), if the patient can tolerate it. This dehydrates the vitreous and removes positive posterior pressure,” Dr. Giaconi said. “If Mannitol isn’t safe, some people will use Acetazolamide preoperatively,” she continued. “If the AC is very shallow, a limited pars plana vitrectomy can be done. “If one isn’t comfortable doing this themselves, one can partner up with a retina surgeon to do it, especially if a retina surgeon operates on the same day as you in your operating rooms,” she said. “It takes them just a couple of minutes to complete and can significantly deepen the anterior chamber and make operating much easier.” Dr. Bedrood said the initial surgical challenge with these eyes is the posterior pressure and the small space within the anterior chamber, which makes it challenging to maneuver instruments. She also recommended using IV Mannitol preoperatively to help decompress the vitreous and move the lens more posteriorly. “I also recommend a femtosecond laser for the rhexis so that there is less potential for the cornea to be touched by instruments during the creation of the rhexis,” she said. “Other considerations include the possibility of iris prolapse, so I will have iris hooks on standby.” About the Physicians Sahar Bedrood, MD, PhD | Glaucoma & Cataract Surgeon, Advanced Vision Care, Los Angeles, California | saharbedrood@gmail.com JoAnn Giaconi, MD | Stein Eye Institute, University of California, Los Angeles, California | giaconi@jsei.ucla.edu Reference 1. Sandhu U, et al. Comparison of IOL calculation formulas for long and short axial length eyes. Invest. Ophthalmol Vis Sci. 2023;64(8):1203. Relevant Disclosures Bedrood: Abbvie, Glaukos, Thea Laboratories, Ocular Therapeutix, BVI, Elios Vision Giaconi: LightTouch This article originally appeared in the March 2024 issue of EyeWorld. It has been slightly modified and appears here with permission from the ASCRS Ophthalmic Services Corp. CATARACT
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