Explore peer-reviewed evidence related to ophthalmic needles, syringes and injection systems. Choose a topic to view relevant publications, concise summaries and links to the full article.
Summary: This retrospective comparative study assessed visual and refractive results and IOL tilt in 37 eyes of 32 patients, comparing 19 eyes that underwent secondary implantation by the Yamane technique against 18 control eyes following phacoemulsification. The transconjunctival sclerotomies were placed 2.0 mm from the limbus at exactly 180 degrees using 30-gauge thin-walled bent needles from TSK Laboratory. Mean best-corrected visual acuity improved from 0.61 +/- 0.39 to 0.10 +/- 0.10 logMAR (p < 0.0001), mean IOL tilt was 3.79 degrees against 0.69 degrees in the control group, and 57.9% of eyes were within 1.00 D of target refraction.
Relevance: Clinical visual, refractive and IOL-tilt outcomes from a Yamane series performed with TSK 30-gauge thin-wall needles, with a phacoemulsification control group for comparison.
Excessive Shear Rate, Not Shear Stress, Influences Cell Mechanical Damage in Small-Bore Needle Injections
George Morgan; Jennifer Frattolin; Lamis Elsawah; Amelie Daudet; Daniel Watson; Nicola Contessi Negrini; Adam D. Celiz; James E. Moore Jr | 2026
Summary: Endothelial cells suspended in fluids of differing viscosities were injected through 30-gauge needles, with the experiments designed so that either shear stress or shear rate was held constant in order to resolve which parameter governs damage. Across fluid types, increasing shear rate explained the reductions in viability better than increasing shear stress, consistent with the otherwise counter-intuitive observation that higher-viscosity carriers give better viability at the same flow rate.
Relevance: Identifies shear rate -- set by internal diameter and flow rate together -- as the variable that governs cell damage, which is more actionable for cannula specification than shear stress. The model used a cell line in simple fluids rather than a therapeutic cell suspension.
Guiding syringe selection for intravitreal injections: injectability and stability analysis of compounded pegcetacoplan (SYFOVRE) and the broader implications for high-viscosity ophthalmic therapies
Tina Felfeli; Natalie M. Lane; Efrem D. Mandelcorn | 2026
Summary: Four syringe types were evaluated for storage stability, particulate contribution, closure integrity and injectability of pegcetacoplan and of high-viscosity mimics. Drug stability was maintained across all four, but particulate performance and injection force differed, and the low-volume ophthalmic-specific syringes required less injection force in the reported tests.
Relevance: As intravitreal therapies become more viscous, injectability becomes a selection criterion alongside stability. This study offers a framework for testing both together across the four syringe models examined.
Felfeli T, Lane NM, Mandelcorn ED, ‘Guiding syringe selection for intravitreal injections: injectability and stability analysis of compounded pegcetacoplan (SYFOVRE) and the broader implications for high-viscosity ophthalmic therapies’, International Journal of Retina and Vitreous, vol. 12, no. 1 (2026), article 63, doi: 10.1186/s40942-026-00832-3.
30G x 13 mmAnterior SegmentClinical outcomesDirect TSK/STERiJECT evidencePRC-300131TSK STERiJECTUltra-thin wallYamane
Macular and Functional Outcomes After Secondary IOL Implantation Using the Yamane Technique in Aphakia, IOL Subluxation, and IOL Dislocation
G. Visioli; G. M. Albanese; S. Magherini; D. Cappiello; C. Baratta; M. Armentano; L. Lucchino; L. Iannetti; M. Gharbiya | 2026
Summary: This retrospective comparative study reported 12-month outcomes after secondary IOL implantation by the Yamane technique in 59 eyes (13 aphakic, 25 with subluxated IOLs, 21 with dislocated IOLs). The scleral tunnels were created 2.50 mm from the limbus using a TSK STERiJECT PRC-300131 30 gauge x 13 mm ultra-thin-walled needle. Best-corrected visual acuity improved significantly across all three groups (p < 0.001), cystoid macular oedema was present in 13.6% of eyes at 12 months with an incident postoperative rate of 10.2%, and baseline acuity was the only independent predictor of visual improvement.
Relevance: Twelve-month clinical outcome data from a series performed with a named TSK STERiJECT product code, in the Yamane application that the ultra-thin-wall 30G needle was designed for.
A modified Yamane technique with a posterior approach in a case report of intraocular lens dislocation
Ludovico Iannetti; Carmen Baratta; Flavia Figliola; Marta Armentano; Giacomo Visioli; Ludovico Alisi | 2025
Summary: This case report describes a modified Yamane intrascleral fixation performed through a posterior approach in the vitreous chamber, in a 56-year-old myopic man with posterior dislocation of the capsular bag and a three-piece IOL with polymethylmethacrylate loops. Following 25-gauge pars plana vitrectomy, a PRC-300131 30 gauge x 13 mm ultra-thin-walled TSK STERiJECT needle was folded to a 70-degree angle and inserted to create a 2.5 mm transconjunctival scleral tunnel, and each PMMA loop was captured with maxgrip forceps and guided into the lumen of the needle before being flanged with low-temperature cautery. Best-corrected visual acuity improved from 1.1 to 0.3 logMAR, and no complications, IOL tilting or dislocation were observed across follow-up at 1 day, 7 days, 1 month and 3 months.
Relevance: Names a specific TSK STERiJECT product code in a technique variant developed for PMMA-loop IOLs, where the loop is threaded through the needle lumen in the vitreous chamber. The evidence level is a single case.
Iannetti L, Baratta C, Figliola F, Armentano M, Visioli G, Alisi L, 'A modified Yamane technique with a posterior approach in a case report of intraocular lens dislocation', International Journal of Surgery Case Reports, vol. 131 (2025), article 111369, doi: 10.1016/j.ijscr.2025.111369.
Summary: This prospective, randomised, single-blinded crossover trial compared perceived pain at two intravitreal injection entry sites, 3.5 mm and 4.0 mm from the limbus, in 53 patients who each received both injections, giving 106 injections in total. All anti-VEGF medication was administered using a 32-gauge Steriject needle from TSK. Mean pain scores were 1.92 +/- 1.64 at 3.5 mm and 1.72 +/- 1.65 at 4.0 mm, a difference that was not statistically significant (p = 0.45), with an overall mean of 1.82 +/- 1.64 on a 0-10 scale.
Relevance: Randomised clinical pain data collected with a TSK STERiJECT 32-gauge needle, showing low reported pain at this gauge that was not materially changed by entry-site distance.
Fan J, Guiseppi R, Digbeu B, Banaee T, 'Perception of pain during intravitreal injections: a clinical trial on the effect of entry site distance from the limbus on perceived pain', International Journal of Retina and Vitreous, vol. 12, no. 1 (2025), article 13, doi: 10.1186/s40942-025-00769-z.
32G x 13 mmAesthetic medicineDirect TSK/STERiJECT evidenceElectron microscopyNeedle tip deformationNon-ophthalmicSharpnessSingle useTSK Laboratory
When to change needles during neuromodulator injections-An electron-microscopy investigation into needle tip deformation
Lisa Akintilo; Jeremy B. Green; Joely Kaufman; Bahar Ghane-Motlagh; David L. Freytag; Konstantin Frank; Michael Alfertshofer; Sebastian Cotofana | 2025
Summary: This electron-microscopy study examined 45 needle tips to quantify how far the tip deforms over sequential injection passes, comparing 30G, 31G and 32G needles across four facial neuromodulator indications; the 32G x 1/2 inch (0.26 x 13 mm) needles were supplied by TSK Laboratory. Mean deformation rose with reuse from 14.8% after three passes to 19.6% after five and 29.2% after ten (p < 0.001), against 4.61% for unused control tips, while damaged regions per tip rose from 4.18 to 5.58 across the same range. By gauge, the TSK 32G needle showed the least deformation at 16.9% against 18.8% for the 31G and 20.3% for the 30G, although this difference did not reach significance (p = 0.753), and the authors recommend exchanging needles after three to five passes.
Relevance: Direct microscopic evidence that a needle tip blunts measurably with repeated passes, which is the mechanical basis for single-use practice, and the finest gauge tested deformed least. The setting is aesthetic facial injection rather than ophthalmic.
Akintilo L, Green JB, Kaufman J, Ghane-Motlagh B, Freytag DL, Frank K, Alfertshofer M, Cotofana S, 'When to change needles during neuromodulator injections-An electron-microscopy investigation into needle tip deformation', Journal of Cosmetic Dermatology, vol. 24 (2025), article e16506, doi: 10.1111/jocd.16506.
Comparing dislocation force between a flanged haptics IOL and a harpoon haptics IOL
Johannes Zeilinger; Martin Kronschlager; Andreas Schlatter; Natascha Bayer; Oliver Findl | 2024
Summary: This laboratory investigation compared the least required dislocation force for two secondary IOL fixation techniques in human corneoscleral donor tissue, testing 20 three-piece IOLs with flanged PVDF haptics against 20 single-piece IOLs with T-shaped harpoon haptics across 10 tissues. In the flanged group the sclera was penetrated and the haptics externalised using a 30 gauge thin-wall needle of 13 mm length from TSK Laboratory Europe. Dislocation force was significantly higher for the flanged haptics at 0.93 +/- 0.43 N than for the harpoon haptics at 0.45 +/- 0.18 N (difference 0.38 +/- 0.25 N, p < 0.001), and three harpoon haptics broke during externalisation while no flanged haptic broke; the authors also note that a 30G thin-walled needle produces a tunnel of about 300 microns against about 400 microns for a 27G needle.
Relevance: Comparative evidence that flanged fixation performed with a TSK 30G thin-wall needle resists axial traction roughly twice as strongly as the harpoon alternative, together with tunnel-diameter figures that show why the thin-wall bore matters to flange fit.
Zeilinger J, Kronschlager M, Schlatter A, Bayer N, Findl O, 'Comparing dislocation force between a flanged haptics IOL and a harpoon haptics IOL', Scientific Reports, vol. 14, no. 1 (2024), article 32085, doi: 10.1038/s41598-024-83774-w.
Development of a novel SupraChoroidal-to-Optic-NervE (SCONE) drug delivery system
Bryce Chiang et al. | 2024
Summary: This study presents a suprachoroidal-to-optic-nerve (SCONE) delivery approach that enables targeted delivery toward the optic nerve head. It is part of a broader movement toward route-specific ocular delivery.
Relevance: Each new route places different demands on cannula length, geometry and flow path, so the delivery device becomes part of the therapeutic design. The work is a proof-of-concept delivery-system study.
Chiang B et al., ‘Development of a novel SupraChoroidal-to-Optic-NervE (SCONE) drug delivery system’, Drug Delivery (2024), doi: 10.1080/10717544.2024.2379369.
Dislocation force of scleral flange-fixated intraocular lens haptics
Spela Stunf Pukl; Martin Kronschlager; Manuel Ruiss; Stephane Blouin; Emre Rustu Akcan; Oliver Findl | 2024
Summary: This laboratory investigation measured the force required to dislocate scleral flange-fixated IOL haptics from their tunnels, testing 19 IOLs with either polyvinylidene fluoride or PMMA haptics. The scleral tunnels were created with a 30 gauge thin-wall needle of 13 mm length from TSK Laboratory Europe. Dislocation force for the 30G tunnels was 1.58 +/- 0.68 N for PVDF haptics against 0.70 +/- 0.14 N for PMMA haptics (p = 0.003), and flange size correlated strongly with dislocation force (r = 0.92) once flanges exceeded 384 microns.
Relevance: Quantifies how tunnel diameter, haptic material and flange size together determine fixation strength when a TSK 30G thin-wall needle creates the tunnel -- useful for needle and IOL selection in flanged fixation.
Stunf Pukl S, Kronschlager M, Ruiss M, Blouin S, Akcan ER, Findl O, 'Dislocation force of scleral flange-fixated intraocular lens haptics', BMC Ophthalmology, vol. 24, no. 1 (2024), article 103, doi: 10.1186/s12886-024-03369-x.
Fine gaugeIntravitrealPatient comfortRetina
Effect of Needle Gauge Size on Pain During Intravitreal Anti-VEGF Injection: A Systematic Review and Network Meta-Analysis
Emilie T. S. Butler et al. | 2024
Summary: A systematic review and network meta-analysis of nine comparative studies (998 patients; 1,004 eyes) found a consistent trend toward lower reported pain with thinner intravitreal needles, and the authors concluded that 30G or thinner needles may minimise discomfort during anti-VEGF injection.
Relevance: The best available synthesis on gauge and patient comfort, and support for fine-gauge selection where the formulation allows it. Gauge is one determinant among several, alongside anaesthesia, injection site and technique.
Butler ETS, et al., ‘Effect of Needle Gauge Size on Pain During Intravitreal Anti-VEGF Injection: A Systematic Review and Network Meta-Analysis’, Ophthalmology and Therapy, vol. 13 (2024), pp. 801–817, doi: 10.1007/s40123-023-00879-7.
Retention Rates of Genetic Therapies Based on AAV Serotypes 2 and 8 Using Different Drug-Delivery Materials
Felix F. Reichel; Peter Kiraly; Immanuel P. Seitz; M. Dominik Fischer | 2024
Summary: This study quantified how much AAV vector is retained inside subretinal delivery hardware, testing an AAV2-based therapy and a clinical-grade AAV8 vector across four cannulas from two manufacturers. Retention of the AAV2 therapy ranged from 10-28% across one manufacturer's products and reached 32% for another cannula, while AAV8 retention ranged from 3-16%; the authors found the tested devices comparable and compatible with both serotypes.
Relevance: Quantifies how much of a gene-therapy dose can remain inside the delivery device -- up to roughly a third -- which makes flow-path volume and contact materials part of dose planning. Benchtop retention measurement, without an infectivity assay.
Reichel FF, Kiraly P, Seitz IP, Fischer MD, 'Retention Rates of Genetic Therapies Based on AAV Serotypes 2 and 8 Using Different Drug-Delivery Materials', International Journal of Molecular Sciences, vol. 25, no. 7 (2024), article 3705, doi: 10.3390/ijms25073705.
Subjective Discomfort during Botulinumtoxin Injections Dependent on Injection Site and Needle Size: A Comparison Between 30G, 33G and 34G Needles
Till A. Kammerer; Randolf Bertlich; Daniela Hartmann; Mark Jakob; Bernhard G. Weiss; Ines Bertlich; Friedrich Ihler; Paul Severin Wiggenhauser; Mattis Bertlich | 2024
Summary: This prospective cohort study in 99 patients across 189 treated regions compared subjective discomfort during botulinum toxin injection using 30G, 33G and 34G needles, all from TSK Laboratory Europe and including the Invisible Needle 34G x 13 mm. Visual analogue pain scores fell consistently as the gauge became finer: on the forehead 3.9 +/- 1.6 for 30G, 2.7 +/- 1.5 for 33G and 1.7 +/- 1.2 for 34G, with the same pattern at the glabella (4.3, 2.7, 1.6) and temple (4.0, 2.2, 0.9), and all differences between needle sizes statistically significant (p < 0.05).
Relevance: Human, within-study evidence that finer TSK gauges are felt less, measured across three gauges including the 34G Invisible Needle. The setting is aesthetic facial injection, so the pain values are specific to that tissue and procedure rather than to intravitreal injection.
Kammerer TA, Bertlich R, Hartmann D, Jakob M, Weiss BG, Bertlich I, Ihler F, Wiggenhauser PS, Bertlich M, 'Subjective Discomfort during Botulinumtoxin Injections Dependent on Injection Site and Needle Size: A Comparison Between 30G, 33G and 34G Needles', Aesthetic Plastic Surgery, vol. 48, no. 13 (2024), pp. 2528-2535, doi: 10.1007/s00266-024-03877-7.
Accuracy, Precision, and Residual Volume of Commonly Used Syringes for Intravitreal Injections and the Impact on Intraocular Pressure
Lydianne L. M. Agra et al. | 2023
Summary: Bench testing across 600 syringe-and-needle configurations used two needle models, including the 34G TSK Invisible Needle. Delivered-volume accuracy, precision and residual volume differed between configurations, and a model eye linked higher delivered volume to larger transient IOP rises.
Relevance: Direct evidence of a TSK needle within a system-level comparison, and a demonstration that delivered dose is a property of the complete syringe-and-needle combination rather than of any single component.
Agra LLM, et al., ‘Accuracy, Precision, and Residual Volume of Commonly Used Syringes for Intravitreal Injections and the Impact on Intraocular Pressure’, Ophthalmology Retina, vol. 7, no. 10 (2023), pp. 892–900, doi: 10.1016/j.oret.2023.06.003.
27G thin-wallDirect TSK/STERiJECT evidenceRetinaSubretinal fluid drainageSurgical techniqueTSK Laboratory InternationalVitreoretinal surgery
Applications of the Guarded-Needle External Drainage Technique in Vitreoretinal Surgery
Tina Felfeli; Parampal S. Grewal; Efrem D. Mandelcorn | 2023
Summary: This surgical technique article presents a step-by-step procedure and surgical video for guarded-needle external drainage, together with a series of representative cases across a wide range of diagnoses. The guarded needle is a 27-gauge thin-walled TSK needle from TSK Laboratory International, fitted with a trimmed 70 buckle sleeve and connected to the active extrusion tubing of the vitrectomy machine, with subretinal fluid aspirated under low active vacuum through a transconjunctival, transscleral route under direct visualisation. The authors set out its use in bullous retinal detachments, detachments with small anterior breaks, prevention of underfill when using oil tamponade, subretinal gas or air, lysing a subretinal band, draining suprachoroidal haemorrhage, diabetic tractional detachments, detachments with no definitive break, and subretinal biopsy in exudative detachments.
Relevance: Documents a TSK 27-gauge thin-wall needle in a vitreoretinal surgical role well beyond injection, with a published technique and video, and shows where the thin-wall bore supports controlled aspiration rather than delivery.
Quantitative assessment of silicone oil release with siliconized and silicone oil-free syringes by microflow imaging microscopy
Lydianne L. M. Agra; Natasha F. S. da Cruz; Vaida Linkuviene; John F. Carpenter; Michel E. Farah; Gustavo B. Melo; Maurício Maia | 2023
Summary: Microflow imaging microscopy quantified the particles released by four commonly used syringe models with several intravitreal drugs, comparing flicked against non-flicked handling. Agitation increased particle release in selected syringe models.
Relevance: Both device selection and preparation technique influence particulate exposure, which is a practical argument for standardised handling protocols. The results describe the four syringe models tested.
Size variability and fitting of 30-gauge thin-wall needles and 3-piece intraocular lens haptics for the flanged intrascleral fixation technique
Spela Stunf Pukl; Martin Kronschläger; Manuel Ruiss; Stephane Blouin; Oliver Findl | 2023
Summary: A laboratory comparison measured five 30G thin-wall needle models and five IOL haptics to assess dimensional variability and haptic-to-needle fit for flanged intrascleral fixation. The TSK needle measured had a mean inner diameter of 194.8 +/- 5.0 microns; most tested haptics fitted most needles, though fit depended on the specific pairing.
Relevance: Published dimensional data for a TSK 30G thin-wall needle, and a basis for choosing a needle and haptic combination by measured internal diameter rather than by nominal gauge alone.
Stunf Pukl S, Kronschläger M, Ruiss M, Blouin S, Findl O, ‘Size variability and fitting of 30-gauge thin-wall needles and 3-piece intraocular lens haptics for the flanged intrascleral fixation technique’, Journal of Cataract & Refractive Surgery, vol. 49, no. 8 (2023), pp. 874–878, doi: 10.1097/j.jcrs.0000000000001210.
A Silicone Oil-Free Syringe Tailored for Intravitreal Injection of Biologics
Torleif T. Gjølberg et al. | 2022
Summary: This development study paired a silicone-oil-free ophthalmic syringe with a 33G x 9 mm TSK Low Dead Space needle under selected storage conditions, assessing the complete system for dead volume, dose accuracy, particle release and biologic stability.
Relevance: Direct evidence of TSK LDS use inside a purpose-built intravitreal delivery system, and a worked example of how a needle is qualified as part of a whole system rather than in isolation.
Gjølberg TT, et al., ‘A Silicone Oil-Free Syringe Tailored for Intravitreal Injection of Biologics’, Frontiers in Ophthalmology, vol. 2 (2022), article 882013, doi: 10.3389/fopht.2022.882013.
Dead spaceDelivered volumeIntravitrealPharma/CDMORetinaSyringe design
Deformation of Aflibercept and Ranibizumab Syringes Causes Variation in Intravitreal Injection Volume and Risks Retinal Tear Formation
Joseph J. Raevis; Colin A. Lemire; David J. Ramsey; James Riccobono; Efren Gonzalez | 2022
Summary: Graded additional force was applied to aflibercept and ranibizumab prefilled syringes and to tuberculin syringes, measuring how far the elastomeric stopper deforms into the syringe dead space and how much extra volume is expelled as a result. At 3.92 N of additional force the three syringes dispensed 17.2%, 11.4% and 0.8% excess volume respectively, and the authors advise against forceful injection and against releasing plunger pressure while the needle remains intravitreal, since elastic recovery can draw vitreous back toward the hub.
Relevance: Dead space is not inert -- under achievable plunger force it can add over 17% to the intended volume. This was bench force testing on three syringe types, without in-eye dosing.
Retinopathy of Prematurity: Advances in the Screening and Treatment of Retinopathy of Prematurity Using a Single Center Approach
Audina M. Berrocal; Kenneth C. Fan; Hasenin Al-Khersan; Catherin I. Negron; Timothy G. Murray | 2022
Summary: This retrospective single-centre review describes a long-running ROP screening and treatment programme and reports that, from 2014 onward, a custom short 32G x 3/16-inch TSK STERiJECT needle was used for injection.
Relevance: Direct evidence of TSK STERiJECT within a sustained neonatal clinical programme, showing where a custom short-length needle became part of routine practice.
Berrocal AM, Fan KC, Al-Khersan H, Negron CI, Murray TG, ‘Retinopathy of Prematurity: Advances in the Screening and Treatment of Retinopathy of Prematurity Using a Single Center Approach’, American Journal of Ophthalmology, vol. 233 (2022), pp. 189–215, doi: 10.1016/j.ajo.2021.07.016.
80 Years of Vision: Preventing Blindness from Retinopathy of Prematurity
Edward H. Wood; Emmanuel Y. Chang; Kinley Beck; Brandon R. Hadfield; Amy R. Quinn; Clio Armitage Harper III | 2021
Summary: This peer-reviewed ROP review discusses the use of a 32G, 4 mm TSK STERiJECT needle as part of neonatal intravitreal injection technique, and places it within a wider screening, treatment and follow-up framework.
Relevance: Review-level coverage of TSK STERiJECT in ROP care, and an illustration of how needle length is matched to neonatal ocular anatomy.
Wood EH, Chang EY, Beck K, Hadfield BR, Quinn AR, Harper CA III, ‘80 Years of Vision: Preventing Blindness from Retinopathy of Prematurity’, Journal of Perinatology, vol. 41 (2021), pp. 1216–1224, doi: 10.1038/s41372-021-01015-8.
A Biomechanical Study of Flanged Intrascleral Haptic Fixation of Three-Piece Intraocular Lenses
Kevin K. Ma; Amy Yuan; Sina Sharifi; Roberto Pineda | 2021
Summary: This biomechanical study measured the geometry of 30G TSK ultra-thin-wall needles and used those needles in cadaveric-sclera testing with several three-piece IOL haptic models. The flange-to-needle diameter ratio correlated strongly with fixation force.
Relevance: Direct evidence of a TSK needle in Yamane-technique research, and a quantitative link between needle internal geometry and the mechanical stability of the resulting fixation.
Ma KK, Yuan A, Sharifi S, Pineda R, ‘A Biomechanical Study of Flanged Intrascleral Haptic Fixation of Three-Piece Intraocular Lenses’, American Journal of Ophthalmology, vol. 227 (2021), pp. 45–52, doi: 10.1016/j.ajo.2021.02.021.
Biomechanical Testing of Flanged Polypropylene Sutures in Scleral Fixation
Amy Yuan; Kevin Ma; Sina Sharifi; Roberto Pineda | 2021
Summary: This experimental study used 30G, 32G and 33G TSK ultra-thin-wall needles to create the sclerotomies for biomechanical testing of flanged polypropylene sutures in cadaveric sclera. Disinsertion force depended on suture gauge, flange length and sclerotomy size.
Relevance: Direct use of three TSK needle gauges in scleral-fixation research, with quantitative guidance on matching sclerotomy size to suture and flange dimensions.
Yuan A, Ma K, Sharifi S, Pineda R, ‘Biomechanical Testing of Flanged Polypropylene Sutures in Scleral Fixation’, American Journal of Ophthalmology, vol. 230 (2021), pp. 134–142, doi: 10.1016/j.ajo.2021.04.017.
Summary: Following a cluster of symptomatic silicone-oil droplets associated with siliconised staked-needle syringes, the centre changed to a silicone-oil-free syringe paired with a TSK Low Dead Space 33G x 9 mm needle. No new symptomatic cases were identified over the following year, and the authors attributed the earlier cluster to the syringe.
Relevance: Direct clinical experience with a TSK LDS needle as part of a workflow change that resolved a device-related complication cluster.
Sivertsen MS, Lode HE, Gjølberg TT, Petrovski G, Andersen JT, Jørstad ØK, Moe MC, ‘Cluster of symptomatic silicone oil droplets following intravitreal injections: a 1-year observational study’, BMJ Open Ophthalmology, vol. 6, no. 1 (2021), article e000764, doi: 10.1136/bmjophth-2021-000764.
Direct TSK/STERiJECT evidenceIntravitreal devicesRetinaReviewTSK Invisible NeedleTSK STERiJECT Control Hub
Critical analysis of techniques and materials used in devices, syringes, and needles used for intravitreal injections
Gustavo B. Melo et al. | 2021
Summary: This comprehensive review lists TSK STERiJECT Control Hub 27G and 30G needles and the TSK Invisible Needle 34G among the intravitreal devices considered, synthesising the evidence on gauge, materials, silicone oil, particulates, sterilisation and handling.
Relevance: Places named TSK products within the peer-reviewed landscape of intravitreal delivery devices, and serves as a single entry point into the technical literature.
Melo GB, et al., ‘Critical analysis of techniques and materials used in devices, syringes, and needles used for intravitreal injections’, Progress in Retinal and Eye Research, vol. 80 (2021), article 100862, doi: 10.1016/j.preteyeres.2020.100862.
Direct TSK/STERiJECT evidenceIntravitrealLot variabilityParticulatesRetinaSTERiJECT Control HubTSK Invisible Needle
High particle variability across siliconized and oil-free syringes and needles from the same lots
Lydianne L. M. Agra et al. | 2021
Summary: This laboratory study found substantial particle-count variability between devices and, notably, within the same production lots. TSK Invisible and STERiJECT Control Hub needles were among the devices tested.
Relevance: Direct comparative data involving named TSK needle models, and evidence that lot-level particulate testing, rather than device model alone, is what characterises particulate performance.
Agra LLM, et al., ‘High particle variability across siliconized and oil-free syringes and needles from the same lots’, Scientific Reports, vol. 11, no. 1 (2021), article 4645, doi: 10.1038/s41598-021-84158-0.
Prospective Study of Silicone Oil Microdroplets in Eyes Receiving Intravitreal Anti-Vascular Endothelial Growth Factor Therapy in 3 Different Syringes
John T. Thompson | 2021
Summary: A prospective examination of 260 treated eyes and 147 uninjected fellow eyes compared the prevalence and severity of silicone-oil microdroplets after repeated anti-VEGF injections delivered with different syringe configurations. Microdroplet prevalence differed markedly by configuration and was 0% in uninjected controls, and the authors recommended silicone-free syringes for repeated intravitreal therapy.
Relevance: Patient-level clinical evidence that syringe selection changes what accumulates in the eye over a long treatment course.
Questionnaire to Assess Life Impact of Treatment by Intravitreal Injections (QUALITII): Development of a patient-reported measure to assess treatment burden of repeat intravitreal injections
Cynthia K. McClard; Rui Wang; Victoria Windham; Jose Munoz; Samuel Gomez; Sagit Fried; Namrata Saroj; Carl Regillo; Charles Clifton Wykoff; Adriana M. Strutt | 2021
Summary: A purpose-built instrument was developed and administered to 142 patients receiving repeat intravitreal injections, identifying five distinct dimensions of treatment burden. The most frequently cited cause of discomfort was the sensation once the anaesthetic wore off, the dominant source of anxiety was fear of the injection and its pain, and patients reported temporary post-injection debilitation taking an average of about eight hours to resolve.
Relevance: Quantifies what patients on a long injection course actually experience, and locates where in the visit the discomfort sits. The instrument measures treatment burden rather than any device variable.
McClard CK, Wang R, Windham V, Munoz J, Gomez S, Fried S, Saroj N, Regillo C, Wykoff CC, Strutt AM, 'Questionnaire to Assess Life Impact of Treatment by Intravitreal Injections (QUALITII): Development of a patient-reported measure to assess treatment burden of repeat intravitreal injections', BMJ Open Ophthalmology, vol. 6, no. 1 (2021), e000669, doi: 10.1136/bmjophth-2020-000669.
Direct TSK/STERiJECT evidenceIntravitrealParticulatesRetinaSilicone oilTSK Invisible NeedleTSK STERiJECT Control Hub
Silicone oil-free syringes, siliconized syringes and needles: quantitative assessment of silicone oil release with drugs used for intravitreal injection
Gustavo B. Melo et al. | 2021
Summary: Imaging flow cytometry compared eight syringe models and eleven needle models, including TSK STERiJECT Control Hub 27G and 30G needles and the TSK Invisible Needle 34G, with ophthalmic drugs under agitated and non-agitated conditions. Silicone-oil release varied by device, and silicone oil was detected in every needle tested.
Relevance: Direct comparative laboratory data on named TSK models, and an important baseline: silicone oil is present across needle types, so exposure is managed through system selection and handling rather than eliminated by any one component.
Stability testing of the Pfizer-BioNTech BNT162b2 COVID-19 vaccine: a translational study in UK vaccination centres
Laila Kudsiova; Alison B. Lansley; Greg Scutt; Marcus Allen; Lucas D. Bowler; Sian Williams; Samantha Lippett; Selma Stafford; Michael Tarzi; Michael B. Cross; Michael Okorie | 2021
Summary: Residual mRNA-lipid nanoparticle vaccine was subjected to a range of realistic mishandling stresses and assessed by dynamic light scattering and gel electrophoresis for particle size, mRNA integrity and lipid composition. Minor physical impacts produced minimal instability, but repeated high-speed needle injection and vigorous shaking progressively widened the particle size distribution and released approximately 50% of the mRNA from the nanoparticles.
Relevance: Demonstrates that passage through a needle can itself degrade a lipid nanoparticle payload, which makes device selection a product-quality question for LNP and mRNA formulations. The stresses applied were deliberately exaggerated repeated passages in a parenteral vaccine, not a single ophthalmic injection.
Kudsiova L, Lansley AB, Scutt G, Allen M, Bowler LD, Williams S, Lippett S, Stafford S, Tarzi M, Cross MB, Okorie M, 'Stability testing of the Pfizer-BioNTech BNT162b2 COVID-19 vaccine: a translational study in UK vaccination centres', BMJ Open Science, vol. 5, no. 1 (2021), e100203, doi: 10.1136/bmjos-2021-100203.
Dose accuracyIntravitrealLDSRetinaVLDS
The influence of dead spaces and the designs of injectors on the amount of drug dose in intra-vitreal injection
Erol Havuz; Seda Güdül Havuz; Onur Gokmen | 2021
Summary: Bench testing of five injector designs showed that dead space and injector geometry can materially change the amount delivered when preparing very small intravitreal doses, and that designs reducing dead space improve agreement between intended and delivered dose.
Relevance: The quantitative basis for why low- and very-low-dead-space configurations matter at intravitreal volumes, where the residual volume can approach the size of the dose itself.
Havuz E, Güdül Havuz S, Gokmen O, ‘The influence of dead spaces and the designs of injectors on the amount of drug dose in intra-vitreal injection’, European Journal of Ophthalmology, vol. 31, no. 2 (2021), pp. 592–599, doi: 10.1177/1120672120977820.
IntravitrealRetinaSilicone oilSyringe handling
Agitation of the syringe and release of silicone oil
Celso de Souza Dias Júnior et al. | 2020
Summary: Laboratory testing of eight syringe models examined silicone-oil release under agitated and non-agitated handling. Flicking the syringe was associated with a 265-fold greater chance of detecting oil droplets than no agitation.
Relevance: One of the clearest demonstrations that preparation technique, not only device choice, determines particulate exposure, and directly actionable in injection protocols.
Dias Júnior CS, et al., ‘Agitation of the syringe and release of silicone oil’, Eye, vol. 34, no. 12 (2020), pp. 2242–2248, doi: 10.1038/s41433-020-0800-9.
BiologicsEndotoxinPharma/CDMOQuality attributes
Ophthalmic biosimilars and biologics-role of endotoxins
Ashish Sharma et al. | 2020
Summary: This article explains the relevance of endotoxins for ophthalmic biologics and biosimilars, and discusses the low endotoxin limits appropriate for intraocular use.
Relevance: Background on why intraocular products and the components that contact them are held to stringent endotoxin control. It is a short commentary rather than a comparative study.
Ashish Sharma et al., ‘Ophthalmic biosimilars and biologics-role of endotoxins’, Eye, vol. 34, no. 4 (2020), pp. 614–615, doi: 10.1038/s41433-019-0636-3.
HandlingIntravitrealRetinaSilicone oilSyringes
Release of silicone oil and the off-label use of syringes in ophthalmology
Gustavo B. Melo et al. | 2020
Summary: Testing of eight syringe models showed that commonly used general-purpose syringes can release silicone oil, particularly after agitation by flicking, with release varying between models.
Relevance: Supports the case for purpose-built ophthalmic devices and controlled handling over the off-label use of general-purpose syringes.
Melo GB, et al., ‘Release of silicone oil and the off-label use of syringes in ophthalmology’, British Journal of Ophthalmology, vol. 104, no. 2 (2020), pp. 291–296, doi: 10.1136/bjophthalmol-2019-313823.
Role of Formulation Parameters on Intravitreal Dosing Accuracy Using 1 mL Hypodermic Syringes
Christian Weinmann; Ahmad S. Sediq; Martin Vogt; Hanns-Christian Mahler; Susanne Joerg; Sergio Rodriguez; Roman Mathaes; Dhananjay Jere | 2020
Summary: Six commercially available 1 mL hypodermic syringes were evaluated dosing target volumes of 100, 50 and 30 microlitres while product viscosity, density and aeration were varied. Increasing viscosity produced higher delivered volumes and therefore higher delivered doses, an effect most pronounced at the smallest target volumes, and surfactant content or high protein concentration causing aeration degraded accuracy.
Relevance: Delivered dose at intravitreal volumes depends on the formulation as much as on the device, so accuracy data generated with water or saline should not be assumed to hold for a viscous biologic. The study varied syringe bodies rather than needle or hub geometry.
SAFER-ROP: Updated Protocol for Anti-VEGF Injections for Retinopathy of Prematurity
Kinley D. Beck et al. | 2020
Summary: This protocol article incorporates a short-needle step and identifies the 32G x 4 mm TSK STERiJECT needle used in the earlier Wright technique from which SAFER-ROP was expanded, alongside guidance on antisepsis, injection location, follow-up and rechecks.
Relevance: Direct protocol-level coverage of TSK STERiJECT within a published ROP anti-VEGF protocol.
Summary: This compounding study paired silicone-oil-free prefilled syringes with TSK Low Dead Space needles (33G x 9 mm and 33G x 13 mm) for aflibercept, ranibizumab and bevacizumab. Under the tested method, one week of storage did not alter the biologics' measured stability, molecular integrity or functional properties.
Relevance: Direct evidence of TSK LDS needles within a validated compounding and storage method, of particular relevance to compounding pharmacies and preparation workflows.
Lode HE, Gjølberg TT, Foss S, Sivertsen MS, Brustugun J, Andersson Y, Jørstad ØK, Moe MC, Andersen JT, ‘A new method for pharmaceutical compounding and storage of anti-VEGF biologics for intravitreal use in silicone oil-free prefilled plastic syringes’, Scientific Reports, vol. 9 (2019), article 18021, doi: 10.1038/s41598-019-54226-7.
Major factors affecting intraocular pressure spike after intravitreal ranibizumab injection: Vitreous reflux and its amount
Enes Uyar; Fatih Ulas; Saygin Sahin; Serdal Celebi | 2019
Summary: A prospective clinical study of 316 eyes in 276 patients measured IOP before injection, immediately after and at 30 minutes, grading vitreous reflux by conjunctival bleb diameter as none, less or more. Immediate post-injection IOP was highest in the no-reflux group and lowest in the more-reflux group (p < 0.001), reflux was the only independent factor affecting IOP change, and both the occurrence and amount of reflux fell as the number of prior injections rose.
Relevance: Reflux acts as a pressure-relief pathway, so reflux and immediate IOP move in opposite directions -- a relationship worth accounting for when interpreting either one. Retained volume was inferred from bleb size in a single-agent (ranibizumab 0.05 mL) series.
Uyar E, Ulas F, Sahin S, Celebi S, 'Major factors affecting intraocular pressure spike after intravitreal ranibizumab injection: Vitreous reflux and its amount', European Journal of Ophthalmology, vol. 29, no. 4 (2019), pp. 361-367, doi: 10.1177/1120672119836613.
IntravitrealNeedlesRetinaSilicone oil
Needles as a source of silicone oil during intravitreal injection
Gustavo B. Melo et al. | 2019
Summary: Chemical analysis demonstrated polysiloxane in two commonly used needle models, with measurable polysiloxane in both the 30G and 26G needles tested, showing that the needle can contribute silicone oil independently of the syringe.
Relevance: Establishes the needle as a component that has to be evaluated in its own right, not only as an accessory to the syringe.
Melo GB, et al., ‘Needles as a source of silicone oil during intravitreal injection’, Eye, vol. 33, no. 6 (2019), pp. 1025–1027, doi: 10.1038/s41433-019-0365-7.
Anterior SegmentCleaningQualitySterilizationTASS
Guidelines for the cleaning and sterilization of intraocular surgical instruments
David F. Chang; Nick Mamalis; OICS Task Force | 2018
Summary: These consensus guidelines address the cleaning and sterilisation of intraocular surgical instruments to prevent toxic anterior segment syndrome, covering endotoxin and residue control, and identifying validated cleaning and final rinsing as key risk-reduction steps.
Relevance: The reference standard for contamination control in anterior segment procedures, and the context for the cleanliness expectations placed on intraocular devices.
Chang DF, Mamalis N, OICS Task Force, ‘Guidelines for the cleaning and sterilization of intraocular surgical instruments’, Journal of Cataract & Refractive Surgery, vol. 44, no. 6 (2018), pp. 765–773, doi: 10.1016/j.jcrs.2018.05.001.
Drug deliveryMicroneedlesPosterior segmentResearch
Intravitreal, Subretinal, and Suprachoroidal Injections: Evolution of Microneedles for Drug Delivery
Rachel R. Hartman; Uday B. Kompella | 2018
Summary: This review covers the evolution of intravitreal, subretinal and suprachoroidal injection routes and of microneedle-based delivery, framing why device geometry matters for posterior-segment delivery.
Relevance: Background on how route selection and needle geometry together determine where a therapy is deposited.
Hartman RR, Kompella UB, ‘Intravitreal, Subretinal, and Suprachoroidal Injections: Evolution of Microneedles for Drug Delivery’, Journal of Ocular Pharmacology and Therapeutics, vol. 34, no. 1-2 (2018), pp. 141–153, doi: 10.1089/jop.2017.0121.
Report of Safety of the Use of a Short 32G Needle for Intravitreal Anti-VEGF Injections for Retinopathy of Prematurity
L. A. Cernichiaro-Espinosa et al. | 2018
Summary: A retrospective multicentre study reported 220 eyes injected with a short TSK STERiJECT 32G needle labelled 4 mm. No corneal ulcer, cataract, endophthalmitis or vitreous haemorrhage was recorded after treatment in the reviewed series.
Relevance: Direct clinical safety experience with TSK STERiJECT in a specialised neonatal protocol, across a multicentre patient series.
Cernichiaro-Espinosa LA et al., ‘Report of Safety of the Use of a Short 32G Needle for Intravitreal Anti-VEGF Injections for Retinopathy of Prematurity’, Retina, vol. 38, no. 6 (2018), pp. 1251–1255, doi: 10.1097/IAE.0000000000002172.
Anterior SegmentEndotoxinPreventionTASS
Toxic anterior segment syndrome-an updated review
Choul Yong Park; Jimmy K. Lee; Roy S. Chuck | 2018
Summary: This updated review summarises the mechanisms, prevention and outcomes of toxic anterior segment syndrome, stressing that TASS is preventable and identifying endotoxin-containing detergents and residues among the key modifiable risks.
Relevance: Explains why endotoxin and residue control are treated as safety-critical for anything entering the anterior segment.
Determination of a No-Observable Effect Level for Endotoxin Following a Single Intravitreal Administration to Dutch Belted Rabbits
Vladimir Bantseev et al. | 2017
Summary: This dose-ranging study established an intravitreal endotoxin no-observable-effect level of 0.01 EU/eye, with inflammation appearing at higher doses.
Relevance: Part of the scientific basis for the strict endotoxin thresholds applied to intraocular components. The findings are preclinical and describe an animal model rather than a human threshold.
Bantseev V et al., ‘Determination of a No-Observable Effect Level for Endotoxin Following a Single Intravitreal Administration to Dutch Belted Rabbits’, Investigative Ophthalmology & Visual Science, vol. 58, no. 3 (2017), pp. 1545–1552, doi: 10.1167/iovs.16-21356.
Flanged Intrascleral Intraocular Lens Fixation with Double-Needle Technique
Shin Yamane et al. | 2017
Summary: This prospective case series introduced flanged intrascleral IOL fixation using two 30G TSK ultra-thin-wall needles, and reported outcomes in 100 eyes.
Relevance: The foundational publication for the Yamane double-needle technique, in which TSK ultra-thin-wall needles were the instruments used.
Subretinal Cell-Based Therapy: An Analysis of Surgical Variables to Increase Cell Survival
David J. Wilson; Martha Neuringer; Jonathan Stoddard; Lauren M. Renner; Steven T. Bailey; Andreas Lauer; Trevor J. McGill | 2017
Summary: To deliver a cell suspension into the subretinal space without leakage into the vitreous, cell viability and recovery were first measured after mock injections through candidate cannulas, then transretinal and transscleral delivery of labelled retinal pigment epithelium cells were compared in 24 animal eyes with histological confirmation. A 30-gauge cannula gave the best cell recovery and viability, and the transscleral approach achieved subretinal encapsulation of the transplanted cells in 100% of cases.
Relevance: Shows that cannula gauge and delivery route together determine how many viable cells reach the subretinal space. A small animal-eye series across a narrow range of cannula gauges.
Technique for Infant Intravitreal Injection in Treatment of Retinopathy of Prematurity
Lauren M. Wright; Ivan M. Vrcek; Frank W. Scribbick III; Emmanuel Y. Chang; C. Armitage Harper III | 2017
Summary: This technique report used a short 32G x 4 mm TSK STERiJECT needle with anatomical specimens to show how a short needle can enter the vitreous cavity while limiting the reach possible with a standard 12 mm needle.
Relevance: Direct evidence of TSK STERiJECT behind the anatomical rationale for short-needle technique in neonatal eyes.
Wright LM, Vrcek IM, Scribbick FW III, Chang EY, Harper CA III, ‘Technique for Infant Intravitreal Injection in Treatment of Retinopathy of Prematurity’, Retina, vol. 37, no. 11 (2017), pp. 2188–2190, doi: 10.1097/IAE.0000000000001561.
Association Between Needle Size, Postinjection Reflux, and Intraocular Pressure Spikes After Intravitreal Injections
Claudine E. Pang; Sarah Mrejen; Quan V. Hoang; John A. Sorenson; K. Bailey Freund | 2015
Summary: A prospective study of 65 eyes compared 30G and 32G needles during anti-VEGF injections, measuring immediate reflux and intraocular pressure; the 32G arm used a TSK STERiJECT needle. The 32G group showed less visible reflux (13% versus 53%) and a higher mean immediate post-injection IOP.
Relevance: Direct clinical data involving a TSK STERiJECT needle, and a clear illustration that reflux and immediate pressure respond differently to gauge, so both are worth measuring together.
Tunnelled versus straight intravitreal injection: intraocular pressure changes, vitreous reflux, and patient discomfort
Pascal Bruno Knecht; Stephan Michels; Veit Sturm; Martina Monika Bosch; Marcel Nico Menke | 2009
Summary: A randomised comparison of tunnelled against straight scleral entry in 60 patients receiving 0.05 mL anti-VEGF measured IOP before injection, within one minute, and every five minutes thereafter. Immediate IOP was 35.97 +/- 8.13 mmHg with the tunnelled technique against 30.19 +/- 12.14 mmHg with the straight technique, all eyes were below 30 mmHg by 15 minutes, reflux occurrence and amount were significantly higher with the straight technique, and pain scores did not differ.
Relevance: Shows that an approach which reduces reflux may conserve dose while raising the immediate pressure spike, so the two endpoints are best read together. The study compared scleral entry techniques, with 30 patients per arm.
Knecht PB, Michels S, Sturm V, Bosch MM, Menke MN, 'Tunnelled versus straight intravitreal injection: intraocular pressure changes, vitreous reflux, and patient discomfort', Retina, vol. 29, no. 8 (2009), pp. 1175-1181, doi: 10.1097/IAE.0b013e3181aade74.
Ex vivoFine gaugeIntravitrealNeedle sharpnessPenetration forceRetina
Scleral penetration force requirements for commonly used intravitreal needles
Jose S. Pulido; Mark E. Zobitz; Kai-Nan An | 2007
Summary: This study measured the force required for 27-, 30- and 31-gauge needles to penetrate sclera. The 27-gauge needles required almost twice the force of the 30- or 31-gauge needles, and the force needed rose after a needle had first been used to perforate a drug vial stopper.
Relevance: Quantifies how much less force a finer needle requires at the sclera, and shows that a tip blunted by vial puncture raises that force -- practical support for fine gauge and for single use. Measurements were made ex vivo, without a patient-reported pain endpoint.
Pulido JS, Zobitz ME, An K-N, 'Scleral penetration force requirements for commonly used intravitreal needles', Eye (London), vol. 21, no. 9 (2007), pp. 1210-1211, doi: 10.1038/sj.eye.6702577.
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Evidence note: Summaries are provided for educational purposes. Studies vary in design and may evaluate devices or configurations other than TSK products. Review the full publication before drawing clinical conclusions. Product availability and indications may vary by market.