Eyeworld

EW CATARACT 36 May 2017 Presentation spotlight by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer topography and anterior chamber depth (ACD) data were obtained using Scheimpflug tomography (Pentacam HR, Oculus, Arlington, Washington). They determined pre- and postoperative AL measurements and K values using the IOLMaster. All refractions were acquired by sub- jective refraction by expert optome- trists using similar refractometers. The main outcome measure was the IOL power prediction error (PE) that Dr. Frings obtained by subtract- ing the SE of the actual refraction from the predicted refraction, which was calculated preoperatively. Sec- ondary outcome measures were SE, ACD, and AL. All operations consisted of standard phaco with clear corne- al incisions and in-the-bag IOL implantations. Study and control eyes all received a one-piece acrylic, foldable Z-haptic IOL (1stQ Basis Z; 1stQ GmbH, Mannheim, Germany), which is used as a standard IOL in Dr. Frings' department and ruled out variability of outcomes based on IOL differences. Three-port PPV was carried out after cataract surgery. Dr. Frings used sulfur hexafluoride (SF6) for all cases of gas tamponade, filling the vitreous cavity almost entirely with 20% SF6 at the end of the operation. In cases without gas endotamponade, BSS was applied. Prior to surgery, patients with phaco- vitrectomy were randomly subjected to either gas or BSS endotamponade. The study enrolled 34 patients with epiretinal membrane and 18 patients with cataract. Differences in the average preoperative ALs between the three study groups were not statistically significant (P>.1). Clinically but not statistically relevant In terms of the primary outcome measures, Dr. Frings observed no statistically significant (P>.05) differ- ences in the resulting IOL power PE between the study groups and the control group. Median PEs in eyes after combined surgery were nega- tive, indicating a myopic tendency for both study groups. Compared to patients of the control group, eyes in study group 1 had a PE of approx- imately 0.7 D thereby resulting in a median SE of –0.88 D. There were no statistically sig- nificant differences between mean phacovitrectomy surgery in pa- tients presenting with vitreoretinal pathology and coexisting cataract. Study group 1 included patients receiving gas endotamponade after combined phacovitrectomy, study group 2 included combined surgeries without gas endotamponade, and study group 3 included patients who underwent cataract surgery alone and served as a control group. The patients were recruited from the University Medical Cen- ter Hamburg-Eppendorf inpatient department starting October 2015. Patients with a diagnosis of epireti- nal membrane and cataract, intend- ed combined unilateral surgery, and the use of the IOLMaster 500 (Carl Zeiss Meditec AG, Jena, Germany) for preoperative IOL calculations were included in the study. Exclu- sion criteria were diabetic vitreous hemorrhage, macular hole, posterior subcapsular and mature cataract, myopia or hyperopia greater than 8.0 D, astigmatism greater than 2.0 D, previous laser refractive surgery, or scleral buckle surgery. Dr. Frings and his team assessed spherical and cylindrical refractions and visual acuity with and without correction, pre- and postoperatively, at 1-day after surgery, and during two consecutive follow-up examina- tions. Pre- and postoperative corneal therefore not unduly influence IOL power calculations. Myopic shift investigation "Several studies have reported that a combined vitreoretinal procedure is a safe and effective way to man- age cases with vitreoretinal disease and cataract, with the functional outcomes comparable to those of sequential surgery. Some have re- ported that eyes with gas tamponade showed a myopic shift compared to eyes without gas tamponade, while other studies explained that the gas tamponade resulted in more zonular elasticity, leading to a more posteri- or IOL position. The IOL type itself also seems to play a major role in potential IOL movement," Dr. Frings said in a poster presentation of his research at the 21st Winter Meeting of the European Society of Cataract & Refractive Surgeons in Maastricht, the Netherlands. Addressing the possible correla- tion between postoperative refrac- tive error and the use of intraocular gas tamponade, Dr. Frings conduct- ed a prospective nonrandomized case-control study in which he compared the surgical outcomes in patients undergoing combined phacovitrectomy, with and without gas endotamponade. Two experi- enced surgeons performed cataract/ Study shows no significant difference in myopic shift in eyes with gas tamponade after phacovitrectomy and cataract controls P ars plana vitrectomy (PPV) combined with phacoemulsification and IOL implantation is per- formed routinely in eyes with vitreoretinal pathology and coexisting cataract. Understanding the factors that impact IOL position in combined cataract/PPV surgery are important in improving refrac- tive outcomes. Among these are inaccuracies in axial length (AL) measurement and the estimated lens position (ELP). The influence of gas tamponade on axial postoperative IOL movements in eyes undergoing phacovitrectomy remains unclear and achieving target spherical equiv- alent (SE) in combined surgery is a subject of continued controversy. According to new research by Andreas Frings, MD, Department of Ophthalmology, University Hospital Duesseldorf, Düsseldorf, Germany, a myopic shift after phacovitrectomy during cataract surgery seems to be independent of the use of intra- ocular gas tamponade and should Owning up to myopic shift: The elusive culprit Intraoperative setting after gasfill in combined phacovitrectomy Source: Marc Schargus, MD

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