Babac Mazinani

Implantation and Explantation of a Wireless Epiretinal Retina Implant Device: Observations during the EPIRET3 Prospective Clinical Trial

PURPOSE Visual sensations in patients with blindness and retinal degenerations may be restored by electrical stimulation of retinal neurons with implantable microelectrode arrays. A prospective trial was initiated to evaluate the safety and efficacy of a wireless intraocular retinal implant (EPIRET3) in six volunteers with blindness and RP. METHODS The implant is a remotely controlled, fully intraocular wireless device consisting of a receiver and a stimulator module. The stimulator is placed on the retinal surface. Data and energy are transmitted via an inductive link from outside the eye to the implant. Surgery included removal of the lens, vitrectomy, and implantation of the EPIRET3 device through a corneal incision. The clinical outcome after implantation and explantation of the device was determined. The implant was removed after 4 weeks, according to the study protocol. RESULTS Implantation was successful in all six patients. While the anterior part was fixed with transscleral sutures, the stimulating foil was placed onto the posterior pole and fixed with retinal tacks. The implant was well tolerated, causing temporary moderate postoperative inflammation, whereas the position of the implant remained stable until surgical removal. In all cases explantation of the device was performed successfully. Adverse events were a sterile hypopyon effectively treated with steroids and antibiotics in one case and a retinal break in a second case during explantation requiring silicone oil surgery. CONCLUSIONS The EPIRET3 system can be successfully implanted and explanted in patients with blindness and RP. The surgical steps are feasible, and the postoperative follow-up disclosed an acceptable range of adverse events.

Accuracy of intraocular lens power calculation using partial coherence interferometry in patients with high myopia.

Citation information: Roessler GF, Dietlein TS, Plange N, Roepke A‐K, Dinslage S, Walter P, Mazinani BAE. Accuracy of intraocular lens power calculation using partial coherence interferometry in patients with high myopia. Ophthalmic Physiol Opt 2012, 32, 228–233. doi: 10.1111/j.1475‐1313.2012.00903.x

Does surgical experience have an effect on the success of retinal detachment surgery

Purpose: To examine the relationship between surgeon experience and success rates in retinal detachment surgery. Methods: Success rates during a follow-up of 11 months of 8 surgeons who performed in total 375 retinal detachment procedures ranging from 14 to 115 cases between December 1997 and January 2002 were correlated to the total number of vitreoretinal procedures ranging between 176 and 2,587. All patients received either scleral buckling or vitrectomy, and complicated cases were excluded. Results: Mean primary anatomical success rates were 0.69 ± 0.14 for scleral buckling and 0.9 ± 0.05 for primary vitrectomy (P < 0.05). The primary anatomical success rates did not correlate to the number of vitreoretinal procedures. Seven of the eight surgeons showed an intraindividual learning effect with better success rates in the second versus the first half of the observed procedures. The learning effect was correlated to the total number of procedures with a higher effect in inexperienced surgeons. Conclusion: An intraindividual learning effect that was higher in inexperienced surgeons could be demonstrated. The learning effect was reduced by half after 500 vitreoretinal procedures while the primary anatomical success rates were not correlated to the number of vitreoretinal procedures.

Accuracy and reproducibility of axial length measurement in eyes with silicone oil endotamponade

Aim: To assess the accuracy and signal quality of axial length measurements by partial coherence laser interferometry (PCI) for optical biometry in eyes with conventional silicone oil (SO) or heavy silicone oil (HSO) as endotamponade. Methods: We included 26 eyes with SO endotamponade (SO, n = 15; HSO, n = 11) using a Zeiss IOLMaster for measurement of axial length the day before and at least 6 weeks after SO removal. We analysed the intra-individual deviation between both measurements and signal-to-noise ratio (SNR) as a marker for signal quality. We included 16 contralateral eyes without history of vitreoretinal surgery to act as the control group. Results: The mean axial length was 24.76 (SD 2.07) mm (SO 24.63 (SD 2.12) mm, HSO 24.93 (SD 2.10) mm, control 24.95 (SD 2.61) mm) before and 24.75 (SD 1.96) mm after oil removal with a mean intra-individual deviation of 0.13 (SD 0.11) mm (SO 0.13 (SD 0.12) mm, HSO 0.13 (SD 0.09) mm, control 0.02 (SD 0.01) mm) while SNR at baseline was 5.7 (SD 3.5) (SO 6.6 (SD 4.0), HSO 4.4 (SD 2.2), control 8.6 (SD 3.9)). Conclusion: In our analysis, optical biometry using PCI generated results with acceptable accuracy and signal quality for measurement of axial length in SO-filled eyes.

Vitrectomy with or without encircling band for pseudophakic retinal detachment: a multi-centre, three-arm, randomised clinical trial. VIPER Study Report No. 1—design and enrolment

Purpose Scleral buckling is currently used in addition to vitrectomy for the treatment of pseudophakic retinal detachment (PRD) to better support the vitreous base and better visualisation of the periphery. Aims The aims of this study are to evaluate (1) whether the combination of 20 G vitrectomy and scleral buckling is superior to 20 G vitrectomy alone (control) (confirmatory), and (2) whether transconjunctival 23/25 G vitrectomy is non-inferior to 20 G vitrectomy (both without scleral buckling) regarding operation success (exploratory). Methods The VIPER (Vitrectomy Plus Encircling Band Vs. Vitrectomy Alone For The Treatment Of Pseudophakic Retinal Detachment) study is an unmasked, multi-centre, three-arm randomised trial. Patients with PRD were eligible, excluding complicated retinal detachment or otherwise severe ophthalmologic impairment. Patients were randomised to one of three interventions: 20 G vitrectomy alone (control C), combination of 20 G vitrectomy and circumferential scleral buckling (experimental treatment E1) or 23/25 G vitrectomy alone (experimental treatment E2). The primary endpoint is the absence of any indication for a retina re-attaching procedure during 6 months of follow-up. Secondary endpoints include best corrected visual acuity, retina re-attaching procedures, complications and adverse events. Results From June 2011 to August 2013, 257 patients were enrolled in the study. The internet randomisation service assigned 100 patients each to the treatment arms C and E1, and 57 patients to treatment E2. The imbalance is due to the fact that several retinal surgeons did not qualify for performing E2. The random assignment was stratified and balanced (ie, 1:1 or 1:1:1 ratio) by surgeon. Conclusions The described study represents a methodologically rigorous protocol evaluating the benefits of three different vitrectomy approaches to PRD. The projected results will help to establish their overall efficacy and will permit conclusions regarding their relative value. Trial registration number DRKS00003158 (German Clinical Trials Register, DRKS).

Improving the quality of multifocal visual evoked potential results by calculating multiple virtual channels.

PurposeTo introduce a method for improvement of multifocal VEP (mfVEP) recordings by prediction of waveforms at multiple positions on the surface of the skull.MethodsFifteen healthy participants (mean age 24 ± 3.8 years) underwent mfVEP recordings from 3 surface positions. Two methods of a best-of-mfVEP approach were used and compared. In the first, a standard procedure, further data from 3 calculated channels were used. In the second approach, mfVEPs were obtained by using data derived from 40 virtual electrode positions on the basis of predictions from dipole source calculations.ResultsThe mean signal-to-noise ratios (SNRs) of the best-of-mfVEPs of both methods were compared. The SNR was significantly higher for mfVEP data using additional virtual recordings revealed by dipole source determination (2.87 vs. 3.36; P < 0.035).ConclusionWe conclude that multichannel prediction of mfVEP responses based on dipole source calculation significantly improves the quality of the examination results compared with the currently prevalent standard method.

Vitrectomy with and without encircling band for pseudophakic retinal detachment: VIPER Study Report No 2—main results

Background It is unclear whether or not an additional encircling band improves outcome in vitrectomy for pseudophakic retinal detachment (PRD). Also unclear is whether small gauge transconjunctival trocar-guided vitrectomy is as successful as conventional 20 gauge (G) vitrectomy. Methods 257 adult patients with uncomplicated PRD were enrolled in 14 vitreoretinal centres across Germany. Contingent on availability of qualified surgeons, eligible patients were randomly assigned either (i) with ratio 1:1 to 20 G vitrectomy plus encircling band (group E1) or 20 G vitrectomy without any buckle (group C) or (ii) with ratios 1:1:1 to group E1, C or 23/25 G vitrectomy without any buckle (group E2). Treatment success was defined as no indication for any retina reattaching procedure during the follow-up of 6 months. Results Success was reached in 79.0% (=79/100, group E1) versus 73.5% (=72/98, group C) (p=0.558, OR 1.32, 95% CI 0.65 to 2.65. In group E2 87.7% (=50/57) of patients reached success compared with 78.7% (=48/61) in group C, demonstrating non-inferiority of E2 to C regarding the prespecified margin of 0.8 (OR scale; p=0.05, OR 2.17, 95% CI 0.80 to 5.89). Best corrected visual acuity significantly increased after surgery independent of technique, that is, on average −0.7 (from 1.0 to 0.3) logMAR. Patients suffered from a shift in spherical refraction of −1.0 D in group E1 compared with −0.1 D in group C. Similarly, intraoperative complications (15.2% vs 8.8% of patients) and serious adverse events (30.3% vs 22.5% of patients) were more frequent in group E1. Conclusions Vitrectomy with gas is an efficient and safe treatment for uncomplicated PRD. An additional encircling band does not significantly reduce the risk for any second procedure necessary to reattach the retina in 20 G vitrectomy. Small gauge transconjunctival vitrectomy is not inferior to the conventional 20 G technique. Trial registration number DKRS 00003158, Results.

Clinical Observations and Occurrence of Complications following Heavy Silicone Oil Surgery

Purpose. To demonstrate development and complications in heavy silicone oil (HSO) surgery in 100 eyes following primary vitreoretinal surgery. Methods. 100 eyes were included in this retrospective study that underwent vitreoretinal surgery using HSO as endotamponade. Indication diagnoses were retinal detachments (n = 76), complicated macular holes (MH) (n = 20), and others (n = 4). HSO removal was performed after a mean period of 20.2 ± 19.0 weeks. In 18 eyes with poor functional prognosis the silicone oil remained permanently for stabilisation. Overall follow-up time was 35.9 ± 51.8 weeks. Results. The mean IOP before HSO surgery was 13.3 ± 5.6 mmHg and raised to an average maximum of 23.3 ± 8.5 mmHg postoperatively and decreased to 13.7 ± 7.2 mmHg after removal. Secondary IOP raise due to emulsification of the silicone oil endotamponade was seen in 29 eyes after 7.8 ± 4.5 weeks. Other complications being observed with HSO installed were persistent corneal erosion (n = 3) and prolonged anterior chamber inflammation (n = 29). In 13 eyes recurrent retinal detachments occurred during followup. Conclusions. According to our analysis HSO surgery might deliver satisfying results in complicated cases of ophthalmological surgery. However, potential complications should always be taken into account when making the decision if to use and when to remove HSO in complicated retinal surgery.

Influence of the prediction error of the first eye undergoing cataract surgery on the refractive outcome of the fellow eye

Introduction In addition to measurement errors, individual anatomical conditions could be made responsible for unexpected prediction errors in the determination of the correct intraocular lens power for cataract surgery. Obviously, such anatomical conditions might be relevant for both eyes. The purpose of this study was to evaluate whether the postoperative refractive error of the first eye has to be taken in account for the biometry of the second. Methods In this retrospective study, we included 670 eyes of 335 patients who underwent phacoemulsification and implantation of a foldable intraocular lens in both eyes. According to the SRK/T formula, the postoperative refractive error of each eye was determined and compared with its fellow eye. Results Of 670 eyes, 622 showed a postoperative refractive error within ±1.0 D (93%), whereas the prediction error was 0.5 D or less in 491 eyes (73%). The postoperative difference between both eyes was within 0.5 D in 71% and within 1.0 D in 93% of the eyes. Comparing the prediction error of an eye and its fellow eye, the error of the fellow eye was about half the value of the other. Conclusion Our results imply that substitution of half of the prediction error of the first eye into the calculation of the second eye may be useful to reduce the prediction error in the second eye. However, prospective studies should be initiated to demonstrate an improved accuracy for the second eye’s intraocular lens power calculation by partial adjustment.

A case of siderosis bulbi without a radiologically detectable foreign body.

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