Eyeworld

127 EW INTERNATIONAL February 2018 loss in the remaining cases. This occurs most often if patients are tracking the green light, which they shouldn't do, or if there is a Bell reflex. About 40% of suction loss cases reviewed, Dr. Reinstein said, were converted to LASIK, depending on when the suction loss occurred. However, the rest were continued as SMILE procedures with no patient of 20 suction losses leaving with- out treatment on the same day. Dr. Reinstein also showed using case controls that there was no difference in vision or safety outcome caused by suction loss. Corneal biomechanics paper session Artashes Zilfyan, MD, Shengavit, Armenia, presented research on a possible new approach to keratoco- nus diagnosis—measuring MMP-9 in tears––in a paper session focused on corneal biomechanics. An increased level of MMP-9, a member of the zinc metalloproteinases family involved in extracellular matrix degeneration, is known to degener- ate collagen IV, which is present in Descemet's membrane. Dr. Zilfyan said it is also known that the onset of keratoconus begins at the level of Descemet's membrane. Based on these factors, Dr. Zilfyan said they hypothesized MMP-9 could trigger keratoconus development. Dr. Zilfyan and fellow research- ers measured the level of MMP-9 in tears of 30 patients with first-, second-, and third-degree kerato- conus (group 1), 30 patients with subclinical keratoconus (group 2), and a control group of 30 patients with no ocular pathology (group 3). They excluded patients with dry eye because it is known to have a correlation with MMP-9. Ninety percent of group 1 had elevated MMP-9 levels, compared to 83.3% of group 2, and 5% in group 3. These results, Dr. Zilfyan said, show that MMP-9 in tear fluid could be used in diagnosis of keratoconus and perhaps other corneal ectasias. Bogdan Spiru, MD, Marburg, Germany, discussed the biomechan- ical weakening of the cornea after different enhancements after SMILE, which he noted is needed in 4% of SMILE procedures. He also included the potential of crosslinking to im- prove the strength of the cornea in these enhancement procedures. Dr. Spiru's research involved 96 porcine eyes that received an initial –11 D SMILE correction with an en- hancement of –3 D. There was one control group that went untreated and five experimental groups: SMILE with re-SMILE enhancement; SMILE with PRK enhancement; SMILE with LASIK enhancement; SMILE, LASIK, and accelerated crosslinking; and accelerated crosslinking only. Biome- chanical properties were measured with stress-strain extensometry after refractive treatments. The results showed that SMILE enhancement and PRK enhance- ment did not induce significant corneal weakening, and crosslinking treatment could compensate for corneal weakening induced by the refractive surgery and even increase corneal stiffness. Further investi- gations in prospective studies with subgroup analysis, such as refrac- tion, treated zone, age, and gender, with biomechanical measurements in vivo are needed, Dr. Spiru said. Endophthalmitis/ocular infections/miscellaneous paper session Andreia Pimenta, PhD, Lisbon, Portugal, presented research on a moxifloxacin-loaded hydrophilic acrylic intraocular lens. The surface of the lens was modified with com- pounds that would allow for loading and sustained drug release of moxi- floxacin for antibiotic prophylaxis in cataract surgery. After soaking and swelling with moxifloxacin, Dr. Pimenta said the optical properties of the IOL were evaluated and were deemed to be within the tolerance range with and without the drug. From an in vitro biocompatibility standpoint, there was no cell growth inhibition higher than 30% observed. The researchers observed sus- tained release of moxifloxacin, and Dr. Pimenta said 90% of the drug was released at day 11. The maxi- mum concentration was about 20 µg/mL, and a concentration of 0.5 µg/mL or more was observed up to 20 days. The research demonstrated that (1) moxifloxacin could be loaded into a commercially available acrylic IOL, (2) optical properties of the IOL were not negatively impacted by the drug loading or storage process, (3) sustained release of moxifloxacin from the IOL is achievable, and (4) collected solutions were still active against Staphylococcus aureus and Staphylococcus epidermidis until 15 days of release, Dr. Pimenta said. Alfonso Vasquez Perez, MD, London, U.K., described long-term outcomes of osteo-odonto-kerato- prosthesis (OOKP) in patients who suffered severe chemical and ther- mal injuries. The analysis included 14 pa- tients—eight who suffered thermal burns and six chemical injuries—re- ferred to the Sussex Eye Hospital, the referral center for OOKP in the U.K., between 2001 and 2016. Sixty-one percent of the patients had either no light perception or evisceration of the contralateral eye. Every eye underwent previous adnexal or ocu- lar surgery including two synthetic KPros. One case had allograft lami- na, and one case suffered choroidal hemorrhage during stage 2 and the lamina was not implanted. Of the patients who received OOKP, 81% retained the lamina at 5 years and 61% at 15 years. However, Dr. Vasquez Perez said functional BCVA of more than 6/60 was only observed in 50% of patients. The pri- mary complication impeding vision was end-stage optic glaucomatous neuropathy, which occurred in four cases; eight patients had preexisting glaucoma prior to this surgery. Mac- ular scar occurred in one case. Because glaucoma was the pre- dominate complication and status of preoperative glaucoma and condi- tion of the optic nerve and macula affect visual success, Dr. Vasquez Perez said IOP should be evaluated and managed after the initial injury. Thermal cases—those caused by direct mechanical and structural damage to all layers of the eye—were particularly difficult, Dr. Vasquez Perez said, noting that functional visual success was only seen in three out of eight thermal burn patients. The fundus and the optic nerve is of- ten difficult to see in these patients preoperatively. Quality of vision and dry eye paper session Sonia Parreira, MD, Almada, Portu- gal, presented on evaluation of ocu- lar surface disease (OSD) in patients after trabeculectomy. She started out by introducing OSD as a multifactorial disease of the tears and ocular surface, whose symptoms can include discomfort, visual disturbance, and tear film instability. Trabeculectomy is a first line surgical treatment for glaucoma. The success rate has significant- ly improved with the adjunctive antimetabolites treatment, but some complications may compromise visual function postoperatively. The aim of Dr. Parreira's study was to compare clinical signs of OSD in patients who had undergone trabeculectomy with and without bevacizumab. The study was a cross sectional, case comparison study of 21 patients (41 eyes). Group 1 included 21 eyes that underwent simple trabeculecto- my. Group 2 included nine eyes that underwent trabeculectomy with in- tracameral bevacizumab. There was also a group including 11 fellow eyes that did not undergo surgery. Pa- tients completed the Ocular Surface Disease Index (OSDI) questionnaire, and total OSDI scores were calculat- ed. Dr. Parreira said that evaluation of fluorescein corneal staining and a Schirmer's tear test with topical anesthesia were executed for every patient. Dr. Parreira explained the grading scale used: Grade 0 with no staining, Grade 1 with mild staining, Grade 2 with moderate staining, and Grade 3 with severe staining. The results compared Schirm- er's tear test, corneal staining, and OSDI scores in Group 1 and Group 2. Additionally, fellow eyes were compared with operated eyes. Dr. Parreira noted that there were no significant differences in the corneal staining score, Schirmer's test results, and OSDI scores between Group 1 and Group 2. The corneal staining score was significantly greater in operated eyes than in non-operated eyes, and fellow eyes had signifi- cantly higher Schirmer's results than eyes with trabeculectomy. OSD is a clinical problem often overlooked in patients who undergo filtration surgery, Dr. Parreira noted. Intracameral bevacizumab could be a safe and possible adjunctive treat- ment without increasing complica- tions, but due to the small sample size in the study, she said further larger randomized trials are required to investigate the long-term results. continued on page 128

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