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Purpose: The German Retina.net ROP registry and its Europe‐wide successor, the EU‐ROP registry, collect data from patients treated for ROP. This analysis compares input parameters of these two registries to establish a procedure for joint analyses of different registry data using exemplary datasets from the two registries. Methods: Exemplary datasets from the two databases over a 1‐year period each (German Retina.net ROP Registry, 2011, 22 infants; EU‐ROP Registry, 2021, 44 infants) were compared. The parameters documented in the two databases were aligned and analysed regarding demographic parameters, treatment modalities, complications within first 24 h and retreatments. Results: The current analysis showed that data can be aligned for joint analyses with some adjustments within the data structure. The registry with more detailed data collection (EU‐ROP) needs to be reduced regarding granularity in order to align the different registries, as the registry with lower granularity determines the level of analyses that can be performed in a comparative approach. In the exemplary datasets, we observed that the overall most common ROP severity in both registries was zone II, 3+ (2011: 70.5%; 2021: 65%), with decreasing numbers of clock hours showing preretinal neovascularisations (2011: 10–12 clock hours in 29% of cases, 2021: 4–6 clock hours in 38%). The most prevalent treatment method was laser coagulation in 2011 (75%) and anti‐VEGF therapy in 2021 (86.1%). Within the anti‐VEGF group, all patients were treated with bevacizumab in 2011 and with ranibizumab in 2021. Retreatment rates were comparable in 2011 and 2021. Conclusion: Data from two different ROP registries can be aligned and jointly analysed. The analysis reveals a paradigm shift in treatment modalities, from predominantly laser to anti‐VEGF, and within the anti‐VEGF group from bevacizumab to ranibizumab in Germany. In addition, there was a trend towards earlier treatment in 2021. [ABSTRACT FROM AUTHOR]

Abstract Background To evaluate the rate, risk factors, functional outcome and prognosis in eyes with retinal detachment after post-operative endophthalmitis treated with 23G Pars Plana Vitrectomy. Methods Electronic patient files from 2009 until 2018 were screened for the presence of an endophthalmitis. Included were 116 eyes of 116 patients. This population was evaluated for the rate of retinal detachment after 23G Pars Plana Vitrectomy for endophthalmitis following cataract surgery or intravitreal injection. The main outcome measures were retinal detachment and visual acuity. Results The reasons for endophthalmitis were previous cataract surgery in 78 patients and following intravitreal injection in 38 patients. The first clinical evidence of endophthalmitis was present in median 5 days after the triggering intervention. Twenty-five eyes (21.55%) developed a retinal detachment an average of 25 days after endophthalmitis. RD is significantly associated with preoperative visual acuity (p = 0.001). Conclusions We emphasize the prognostic role of preoperative visual acuity in RD development of the endophthalmitis treated with 23G Pars Plana Vitrectomy.

Background: Artificial intelligence (AI) has the potential to increase the affordability and accessibility of eye disease screening, especially with the recent approval of AI-based diabetic retinopathy (DR) screening programs in several countries., Methods: This study investigated the performance, feasibility, and user experience of a seamless hardware and software solution for screening chronic eye diseases in a real-world clinical environment in Germany. The solution integrated AI grading for DR, age-related macular degeneration (AMD), and glaucoma, along with specialist auditing and patient referral decision. The study comprised several components: (1) evaluating the entire system solution from recruitment to eye image capture and AI grading for DR, AMD, and glaucoma; (2) comparing specialist's grading results with AI grading results; (3) gathering user feedback on the solution., Results: A total of 231 patients were recruited, and their consent forms were obtained. The sensitivity, specificity, and area under the curve for DR grading were 100.00%, 80.10%, and 90.00%, respectively. For AMD grading, the values were 90.91%, 78.79%, and 85.00%, and for glaucoma grading, the values were 93.26%, 76.76%, and 85.00%. The analysis of all false positive cases across the three diseases and their comparison with the final referral decisions revealed that only 17 patients were falsely referred among the 231 patients. The efficacy analysis of the system demonstrated the effectiveness of the AI grading process in the study's testing environment. Clinical staff involved in using the system provided positive feedback on the disease screening process, particularly praising the seamless workflow from patient registration to image transmission and obtaining the final result. Results from a questionnaire completed by 12 participants indicated that most found the system easy, quick, and highly satisfactory. The study also revealed room for improvement in the AMD model, suggesting the need to enhance its training data. Furthermore, the performance of the glaucoma model grading could be improved by incorporating additional measures such as intraocular pressure., Conclusions: The implementation of the AI-based approach for screening three chronic eye diseases proved effective in real-world settings, earning positive feedback on the usability of the integrated platform from both the screening staff and auditors. The auditing function has proven valuable for obtaining efficient second opinions from experts, pointing to its potential for enhancing remote screening capabilities., Trial Registration: Institutional Review Board of the Hamburg Medical Chamber (Ethik-Kommission der Ärztekammer Hamburg): 2021-10574-BO-ff., (© 2024. The Author(s).)

Background: This study was to compare the outcomes of 360° intra-operative laser retinopexy (ILR) and focal laser retinopexy in treating patients with pars plans vitrectomy (PPV) for primary rhegmatogenous retinal detachment (RRD). To identify other potential risk factors for retinal re-detachment after primary PPV., Methods: This was a retrospective cohort study. Three hundred and forty-four consecutive cases of primary rhegmatogenous retinal detachment treated with PPV were included between July 2013 and July 2018. Clinical characteristics and surgical outcomes were compared between focal laser retinopexy and additional 360° intra-operative laser retinopexy groups. Both univariate and multiple variable analysis were used to identify potential risk factors for retinal re-detachment., Results: Median follow-up was 6.2 months (Q1, Q3:2.0, 17.2). As estimated with survival analysis, the 360º ILR group had the incidence of 9.74% and focal laser 19.54% at 6 months postoperatively. At 12 months postoperatively the difference was 10.78% vs. 25.21%. The difference in survival rates was significant (p = 0.0021). In multivariate Cox regression, the risk factors for retinal re-detachment were without additional 360° ILR, diabetes and macula off before the primary surgery (relatively OR = 0.456, 95%-CI [0.245-0.848], p < 0.05; OR = 2.301, 95% CI [1.130-4.687], p < 0.05; OR = 2.243, 95% CI [1.212-4.149], p < 0.05)., Conclusion: Additional 360° ILR group had a significantly lower rate of retinal re-detachment when compared with focal laser retinopexy group. Our study also elucidated that diabetes and macular off before the primary surgery might also be the potential risk factors for higher rate of retinal re-detachment outcome., Trial Registration: This was a retrospective cohort study., (© 2023. The Author(s).)

Aim: To assess the accuracy of an artificial intelligence (AI) based software (RetCAD, Thirona, The Netherlands) to identify and grade age-related macular degeneration (AMD) and diabetic retinopathy (DR) simultaneously based on fundus photos., Methods: This prospective study included 1245 eyes of 630 patients attending an ophthalmology day-care clinic. Fundus photos were acquired and parallel graded by the RetCAD AI software and by an expert reference examiner for image quality, and staging of AMD and DR. Adjudication was provided by a second expert examiner in case of disagreement between the AI software and the reference examiner. Statistical analysis was performed on eye-level and on patient-level, by summarizing the individual image level-gradings into and eye-level or patient-level score, respectively. The performance of the RetCAD system was measured using receiver operating characteristics (ROC) analysis and sensitivity and specificity for both AMD and DR were reported., Results: The RetCAD achieved an area under the ROC (Az) of 0.926 with a sensitivity of 84.6% at a specificity of 84.0% for image quality. On image level, the RetCAD software achieved Az values of 0.964 and 0.961 with sensitivity/specificity pairs of 98.2%/79.1% and 83.9%/93.3% for AMD and DR, respectively. On patient level, the RetCAD software achieved Az values of 0.960 and 0.948 with sensitivity/specificity pairs of 97.3%/73.3% and 80.0%/90.1% for AMD and DR, respectively. After adjudication by the second expert examiner sensitivity/specificity increases on patient-level to 98.6%/78.3% and 100.0%/92.3% for AMD and DR, respectively., Conclusion: The RetCAD offers very good sensitivity and specificity compared to manual grading by experts and is in line with that obtained by similar automated grading systems. The RetCAD AI software enables simultaneous grading of both AMD and DR based on the same fundus photos. Its sensitivity may be adjusted according to the desired acceptable sensitivity and specificity. Its simplicity cloud base integration allows cost-effective screening where routine expert evaluation may be limited., (International Journal of Ophthalmology Press.)

Purpose: An increasing number of posterior segment disorders is routinely managed with pars plana vitrectomy (PPV). In older, phakic patients cataract formation is expected within the first two years after surgery. For younger patients its progression is individually fluctuating. This study uses an objective quantitative measurement for lens-status-monitoring after PPV with silicone oil to derive predictions for progression and severity of post-operative lens opacification evaluated in patients with rhegmatogenous retinal detachment (RRD)., Methods: Data acquisition was performed prospectively between March 2018 and March 2021. PentacamHR® Nucleus Staging mode (PNS) was used to objectively gather data about nuclear cataracts after PPV at different time points. Data was grouped into training and test sets for a mathematical prediction model. Via backward variable selection method a mathematical formula was set up by means of which predictions about lens densitometry (LD) can be calculated., Results: 20 males [58.8%] and 14 females [41.2%] matched the inclusion criteria (mean age 50.6 years [23-75; ±12.3]). Average follow-up was 8.1 months (3,4-17.4; ±3.4). Mean baseline LD of the treated and fellow eye before surgery was 11.1% (7.7%-17.6%; ±2.0) and 11.2% (7.7%-14.8%; ±1.5), respectively. Predicted LD values by the model for five pre-selected patients closely match the observed data with an average deviation of 1.06%., Conclusions: Using an objective parameter like LD delivered by the PentacamHR® PNS mode additionally to the patient's age allows us to make an individual prediction for any time after PPV with silicone oil due to RRD for all ages. The accuracy of the model was stronger influenced by baseline LD as cofactor in the equation than patient's age. The application for the prediction lens opacification [which can be accessed for free under the following link (https://statisticarium.com/apps/sample-apps/LensDensityOil/)] can help vitreoretinal surgeons for patient consultation on the possibility to combine PPV with cataract surgery., Competing Interests: The authors have declared that no competing interests exist.

Purpose: To investigate the efficacy and safety profile of retinal tacks (RTs) in cases of retinal detachment (RD) with advanced proliferative vitreoretinopathy (PVR)., Materials and Methods: In this single-center, retrospective study medical record, optical coherence tomography and ultra-widefield fundus images of patients with complex PVR-related and RT surgery were reviewed. All cases underwent 23G pars plana vitrectomy (PPV), RT implantation, retinectomy, circumferential intraoperative laser retinopexy, and silicone oil tamponade., Results: Fourteen eyes of 14 patients with complex rhegmatogenous RD with PVR were included: 7 cases showed PVR grade C type P and 7 combined grades A and P. RTs were positioned at contracted, stiffened retinal areas to achieve attachment of retinectomy borders after extensive PVR peeling. Patients underwent on an average of 1.3 PPVs (range 0-3) prior RT surgery. An average of 2.5 RTs (range 1-4) were implanted. Only in a single eye, a recurrent RD occurred. In 10 eyes, the silicone oil tamponade was still in place at the last follow-up. In 5 eyes, the silicone oil could be removed without redetachment in all of these cases (average of 31.3 weeks, range 11.4-53). No RT-related intraoperative or postoperative complications like dislocation or bleedings were observed., Conclusion: RTs have the potential to improve the treatment of complex PVR-associated RD. RT can be a useful surgical tool to reattach borders of retinectomies in advanced PVR. No RT-associated complication were observed in this study., Competing Interests: The authors have no conflicts of interest to declare., (Copyright © 2022 Luca Mautone et al.)

Aim: To investigate the safety of vitreoretinal surgery when using a soft contact lens as a temporary keratoprosthesis (TKP) in patients with severe corneal opacifications., Methods: Three patients with simultaneous corneal and vitreoretinal pathology were treated with a soft contact lens that was used as a TKP to facilitate vitreoretinal surgery. The soft contact lens was fixated with sutures onto the globe so that no leakage was possible., Results: Vitreoretinal surgery with excellent fundus view was possible in all cases. The soft contact lens allowed safe central and peripheral vitrectomy. Surgery was successful in all cases., Conclusion: A soft contact lens properly fixated on the globe can successfully replace a TKP. This surgical procedure has several advantages like one size fits all, low costs, and easy access to the material., (International Journal of Ophthalmology Press.)

Aim: To elucidate the question of whether the ocular trauma score (OTS) and the zones of injury could be used as a predictive model of traumatic and post traumatic retinal detachment (RD) in patients with open globe injury (OGI)., Methods: A retrospective observational chart analysis of OGI patients was performed. The collected variables consisted of age, date, gender, time of injury, time until repair, mechanism of injury, zone of injury, injury associated vitreous hemorrhage, trauma associated RD, post traumatic RD, aphakia at injury, periocular trauma and OTS in cases of OGI., Results: Totally 102 patients with traumatic OGI with a minimum of 12mo follow-up and a median age at of 48.6y (range: 3-104y) were identified. Final best corrected visual acuity (BCVA) was independent from the time of repair, yet a statistically significant difference was present between the final BCVA and the zone of injury. Severe trauma presenting with an OTS score I ( P <0.0001) or II ( P <0.0001) revealed a significantly worse BCVA at last follow up when compared to the cohort with an OTS score >III. OGI associated RD was observed in 36/102 patients (35.3%), whereas post traumatic RD (defined as RD following 14d after OGI) occurred in 37 patients (36.3%). OGI associated RD did not correlate with the OTS and the zone of injury ( P =0.193), yet post traumatic RD correlated significantly with zone III injuries ( P =0.013)., Conclusion: The study shows a significant association between lower OTS score and zone III injury with lower final BCVA and a higher number of surgeries, but only zone III could be significantly associated with a higher rate of RD., (International Journal of Ophthalmology Press.)

Purpose: To identify mechanical factors, as well as patients' biometric and surgeons' experience factors that correlate with the FF incidence in microkeratome (MK)-assisted LASIK and to construct a predictive model based on these parameters., Methods: 55,700 consecutive LASIK treatments of 28,506 patients between January 2017 and April 2020 done by 50 surgeons in 10 centers, all with Sub Bowman Keratome (SBK) and 90μ head (OUP) were analyzed retrospectively for the incidence of FF and their correlation to mean keratometry, central corneal thickness, MK ring height and stop, as well as surgeons' experience. A prediction model was built and tested for sensitivity and specificity., Results: The incidence of FF using the SBK MK was 0.276%. Risk factors were low central corneal thickness, very flat (-1) or very thick (+2) ring height, and higher stop values (p<0.001). Mean keratometry and low surgeon experience were not correlated to FF incidence. A prediction model with a cut-off FF risk of 0.274%, a 76% specificity, and a 73% sensitivity was applied., Conclusions: Free flaps are rarely seen in modern MK LASIK. However, the incidence of this complication using the SBK MK increases using higher stop values, very thick and very thin MK rings, and in eyes with thin corneas., Competing Interests: The authors declare that they have no financial and proprietary interests in relation to this article and that they received no public and private support in relation to this article.

Purpose: Lens opacification is a common complication after pars plana vitrectomy (PPV) and knowing its progression would facilitate consulting patients. The purpose of this study was to evaluate a quantitative model for lens-status-monitoring after PPV with C3F8 gas. Our model was evaluated in rhegmatogenous retinal detachment (RRD) patients of various age and lens densitometry (LD)., Methods: Data between March 2018 and March 2020 were evaluated retrospectively. LD measurements of the PentacamHR® Nucleus Staging mode (PNS) were used to quantify lens opacification over time. A mixed-effect regression model was designed, to enable LD predictions at any time postoperatively. Calculations were based on patient's age and baseline LD as dependent variables. Six patients were randomly excluded during model development, to be used for testing its power afterwards., Results: 34 patients (male 19 [55.9%], female 15 [44.1%]) matched the inclusion criteria. Average age was 58.5 years (32-77;±4.3) and average follow-up was 7.2 months (3,4-23.1;±1,8). Mean baseline LD of the treated and fellow eye before surgery were 10.9% (8.7%-14.8%;±0.8) and 10.7% (8.5%-14.1%;±0.6), respectively. Using our prediction model, LD values for the six pre-selected patients closely match the observed data with an average deviation of 1.07%., Conclusions: Evaluation of age and baseline LD using a mixed-effect regression model might predict cataract progression in RRD patients treated with PPV and C3F8-gas. Such a tool could be considered during cataract surgery consultation in these patients., Competing Interests: The authors have declared that no competing interests exist.

Background: To compare and assess the efficacy of three surgical methods for the treatment of acute submacular hemorrhage (ASH): pneumatic displacement with C2F6, in combination with intravitreal injection of bevacizumab and rtPA, pars plana vitrectomy (PPV) with intravitreal injection of gas (C2F6), bevacizumab and subretinal injection of recombinant tissue plasminogen activator (rtPA), pars plana vitrectomy (PPV) with intravitreal injection of gas (C2F6), bevacizumab and intravitreal injection of recombinant tissue plasminogen activator (rtPA)., Methods: The study included 85 patients with ASH. In the group without PPV (A), patients were treated with intravitreal injection of C2F6, bevacizumab and rtPA. In the second and third group, patients underwent a PPV, intravitreal injection of bevacizumab, pneumatic displacement with C2F6 and a subretinal (B) or intravitreal (C) injection of recombinant tissue plasminogen activator (rt PA)., Results: In group A, mean BCVA increased from preop logMAR 1.41 to 1.05, in group B from 1.46 to 1.28 and in group C from 1.63 to 1.33. In group A, CFT changed from 764 ± 340 μm at time point 0 to 246 ± 153 μm at time point 1, in group B from 987 ± 441 μm to 294 ± 166 μm and in group C from 642 ± 322 μm to 418 ± 364 μm. Patients had an average of 5 injections after surgery., Conclusion: Our study demonstrates that the three methods are equally effective in improving the morphology and the BCVA of patients with ASH., Competing Interests: Competing interestsThe authors declare that they have no competing interests., (© The Author(s) 2020.)

Purpose: Whether retinal degeneration is part of the degenerative processes in patients with Parkinson's disease (PD) is still unclear. This cross-sectional study was undertaken to compare the retinal morphology of patients with PD and healthy controls using spectral domain optical coherence tomography (SD-OCT) and scanning laser polarimetry (SLP)., Methods: Both eyes of patients with PD (n = 108) and healthy controls (n = 165) were examined using SD-OCT and SLP on the same day. Data on the thickness of the retinal nerve fibre layer (RNFL) of all quadrants and the macular area were acquired by OCT (Cirrus, Zeiss). The SLP device (Glaucoma diagnostics (GDx), Zeiss) measured the RNFL and calculated the nerve fibre index (NFI). All patients and probands were checked for concomitant ocular disorders by an ophthalmologist. Visual acuity, intraocular pressure (IOP), objective refraction and the anterior and posterior segment were assessed., Results: Patients with PD showed a reduced macular volume and a reduced central subfield thickness in OCT examinations. The RNFL in the different quadrants did not differ significantly from that of controls. SLP data showed a reduced average RNFL thickness, a decreased thickness of the inferior quadrant and an increase of the NFI in patients with PD., Conclusion: PD may be associated with reduced thickness and volume of the macula and a reduced thickness of the RNFL in the inferior quadrant of the retina. Investigations using SD-OCT and SLP revealed distinct but significant differences between patients with PD and healthy controls., (© 2015 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

A sustained intraocular administration of neurotrophic factors is among the strategies aimed at establishing treatments for currently untreatable degenerative retinal disorders. In the present study we have analyzed the neuroprotective effects of a continuous neural stem (NS) cell-based intraocular delivery of ciliary neurotrophic factor (CNTF) on photoreceptor cells in the nclf mouse, an animal model of the neurodegenerative lysosomal storage disorder variant late infantile neuronal ceroid lipofuscinosis (vLINCL). To this aim, we genetically modified adherently cultivated NS cells with a polycistronic lentiviral vector encoding a secretable variant of CNTF together with a Venus reporter gene (CNTF-NS cells). NS cells for control experiments (control-NS cells) were modified with a vector encoding the reporter gene tdTomato. Clonal CNTF-NS and control-NS cell lines were established using fluorescent activated cell sorting and intravitreally grafted into 14 days old nclf mice at the onset of retinal degeneration. The grafted cells preferentially differentiated into astrocytes that were attached to the posterior side of the lenses and the vitreal side of the retinas and stably expressed the transgenes for at least six weeks, the latest post-transplantation time point analyzed. Integration of donor cells into host retinas, ongoing proliferation of grafted cells or adverse effects of the donor cells on the morphology of the host eyes were not observed. Quantitative analyses of host retinas two, four and six weeks after cell transplantation revealed the presence of significantly more photoreceptor cells in eyes with grafted CNTF-NS cells than in eyes with grafted control-NS cells. This is the first demonstration that a continuous intraocular administration of a neurotrophic factor attenuates retinal degeneration in an animal model of neuronal ceroid lipofuscinosis.

Purpose: In eyes with a preoperative plano refractive cylinder, it would appear that there is no rationale for astigmatic treatment. The aim of this retrospective, cross-sectional data analysis was to determine the amount of topographic astigmatism in refractive plano eyes that results in reduced efficacy after myopic laser in situ keratomileusis (LASIK)., Methods: This study included 267 eyes from 267 consecutive myopic patients with a refractive plano cylinder. Receiver operating characteristic analysis was used to find the cut-off values of preoperative ocular residual astigmatism (= topographic astigmatism) that can best discriminate between groups of efficacy and safety indices in preoperative plano refractive cylinder eyes., Results: Preoperative ocular residual astigmatism (ORA) (or topographic astigmatism) of ≤0.9 diopters (D) resulted in an efficacy index of at least 0.8 statistically significantly more frequently than eyes with a preoperative ORA of >0.9 D. Eyes with a high ORA preoperatively also had a high ORA postoperatively. Regression analysis showed that each diopter of preoperative ORA reduced efficacy by 0.07., Conclusion: A preoperative corneal astigmatism of ≥0.9 D could (partially) be taken into account in the LASIK design, even if the subjective refractive astigmatism is neutral.

Introduction: Intraocular hemorrhage in patients suffering from aneurysmal subarachnoid hemorrhage is known as Terson's syndrome and is an underestimated but common pathology. We therefore designed a prospective single-blinded study to evaluate the validity of ocular ultrasound compared to the gold standard indirect funduscopy in the diagnosis of Terson's syndrome., Material and Methods: Fifty-two patients (104 eyes in total) suffering from aneurysmal subarachnoid hemorrhage were enrolled in this study. Two investigators independently performed a single-blinded ocular ultrasound using a standard intensive care ultrasound system to detect an intraocular hemorrhage. Indirect funduscopy following iatrogenic mydriasis served as the gold standard for confirmation or exclusion of an intraocular hemorrhage. Statistical analyses were performed to evaluate the sensitivity and specificity, positive and negative predictive values of the method as well as the learning curve of ocular ultrasound., Results: Indirect funduscopy detected Terson's syndrome in 11 of 52 (21.2%) respectively in 21 of 104 (20.2%) eyes in patients suffering from subarachnoid hemorrhage. Sensitivity and specificity increased with the number of ocular ultrasound examinations for both investigators, reaching 81.8% and 100% respectively. Positive and negative predictive values were different for both investigators (63.6% vs. 100% positive and 100% vs. 95.7% negative) but were both correlated to the amount of intraocular hemorrhage. A low Glasgow Coma scale (p = 0.015) and high Hunt & Hess grade (p = 0.003) was associated with a higher rate of Terson's syndrome., Conclusions: Ocular ultrasound using standard ultrasound equipment has been confirmed as a reliable, easy-to-handle bedside screening tool for detecting Terson's syndrome. Nevertheless funduscopy remains the gold standard to detect Terson's syndrome.

Purpose: The relationship between number of laser burns of cyclophotocoagulation (CPC) and intraocular pressure (IOP) reduction is unknown. This animal model was established to reveal a possible dose-response-relationship between the number of applied laser burns and the IOP lowering effect., Methods: 30 chinchilla bastard rabbits were divided into 5 groups and treated with either 1, 5, 10, 20, or 30 CPC burns, respectively. IOP was followed up for 1 week. IOP reduction of a single 30-burn treatment was compared with a fractionated treatment (three sessions; one week in between; 10 burns/session)., Results: IOP reduction increases nonlinearly with the number of CPC burns (max. -6.1 ± 1.4 mmHg). Fractionated treatment shows similar IOP reduction with less complications and more constant results compared to single session treatment., Conclusions: The study reveals a complex relationship between IOP reduction and the number of CPC burns. Fractionated CPC gives comparable IOP reduction at a higher degree of safety.

A continuous intraocular delivery of neurotrophic factors (NFs) is being explored as a strategy to rescue photoreceptor cells and visual functions in degenerative retinal disorders that are currently untreatable. To establish a cell-based intraocular delivery system for a sustained administration of NFs to the dystrophic mouse retina, we used a polycistronic lentiviral vector to genetically modify adherently cultivated murine neural stem (NS) cells. The vector concurrently encoded a gene of interest, a reporter gene, and a resistance gene and thus facilitated the selection, cloning, and in vivo tracking of the modified cells. To evaluate whether modified NS cells permit delivery of functionally relevant quantities of NFs to the dystrophic mouse retina, we expressed a secretable variant of ciliary neurotrophic factor (CNTF) in NS cells and grafted the cells into the vitreous space of Pde6b(rd1) and Pde6b(rd10) mice, two animal models of retinitis pigmentosa. In both mouse lines, grafted cells attached to the retina and lens, where they differentiated into astrocytes and some neurons. Adverse effects of the transplanted cells on the morphology of host retinas were not observed. Importantly, the CNTF-secreting NS cells significantly attenuated photoreceptor degeneration in both mutant mouse lines. The neuroprotective effect was significantly more pronounced when clonally derived NS cell lines selected for high expression levels of CNTF were grafted into Pde6b(rd1) mice. Intravitreal transplantations of modified NS cells may thus represent a useful method for preclinical studies aimed at evaluating the therapeutic potential of a cell-based intraocular delivery of NFs in mouse models of photoreceptor degeneration.