MAR 2020

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

Issue link: https://digital.eyeworld.org/i/1215009

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84 | EYEWORLD | MARCH 2020 G PRESENTATION SPOTLIGHT UCOMA by Stefanie Petrou Binder, MD Contributing Writer A study investigated the influence of two common anti-glaucoma proce- dures—the EX-PRESS Glaucoma Filtration Device (Alcon) and trabe- culectomy—on corneal biochemical properties, finding that both proce- dures significantly affected corneal hysteresis (CH) and corneal resistance factor (CRF). "None of the indices returned to the preoperative values 1 year after surgery," Aristeidis Konstantinidis, MD, the study's first author, said in a presentation about the study. What happens to CH and CRF? The prospective study included 30 patients and took place from July 2013 to May 2016. Eighteen patients had an EX-PRESS device inserted (group 1) and 12 patients underwent trabeculectomy (group 2). Group 1 included eight individuals with primary open angle glaucoma (POAG) and 10 patients with pseudoexfoliation glaucoma (PXG), ranging in age from 16–81 years (mean 62.4 years). The mean preoperative IOP in this group was 29.4±7.39 mm Hg, and the mean number of drops the patients required was 2.2±0.7. Before surgery, the CH was 7.31±1.13 and the CRF was 10.6±2.76. Group 2 included five patients with POAG and seven with PXG who ranged in age from 60–78 years of age (mean 67.2 years). The mean preoperative IOP was 33.2±8.61 mm Hg and mean drops was 2.3±0.6. The CH was 7.82±2.55 and CRF was 11.11±1.99 preop. The patients in both treatment groups were examined between 1–3 weeks preoperatively and at 1 month, 6 months, and 12 months post- operatively. All patients had a thorough ophthal- mic examination at all time points and corneal biochemical properties were measured by Ocular Response Analyzer tonometer (Reichert Technologies). Measurements with a waveform score in excess of 3.5 were excluded. CH was significantly increased at all postoperative time points compared to the baseline values, in both the EX-PRESS and trabeculectomy groups. CRF was signifi- cantly decreased at all time points post- operatively, compared to the preoperative values. "We also compared the difference in preoperative versus postoperative val- ues at all time points of CH between the two groups (Welch test), and we did not detect any significant differences between surgical techniques," Dr. Konstantinidis said. "Differences in CRF between the two techniques from preoperative to postop- erative values, at all time points, using the unpaired t-test, were not found to be significant." The study revealed that the IOP was significantly reduced at all postoperative time points for both procedures. The difference in the hypotensive effect was similar for both procedures. Why CH is an important parameter Corneal hysteresis is a reliable predictor How anti-glaucoma procedures affect corneal biomechanics About the doctor Aristeidis Konstantinidis, MD Department of Ophthalmology General University Hospital of Alexandroupolis Alexandroupolis, Greece The EX-PRESS device inserted in the eye Source: Aristeidis Konstantinidis, MD

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