To compare accuracy, precision, and residual volume of commonly used syringes for intravitreal injections (IVI), and to assess the intraocular pressure (IOP) rise by variations in volumes delivered. Experimental lab study. No subjects were involved in this study. We tested 8 syringe models with 2 different needle setups, with 2 different solutions (distilled water or glycerin) and target volumes (50 and 70 μL). To obtain the delivered and residual volumes, we weighed the syringe-needle setups with scale before liquid withdrawal, with liquid, and after liquid release. We also created an experimental eye model to determine the transient rise in IOP following stepwise 10-μL increases in injection volumes. Delivered and residual volumes, IOP rise. We tested a total of 600 syringe-needle setups. BD Ultra-Fine (0.34 ± 0.28 μL), Zero Residual (1.53 ± 1.15 μL) and Zero Residual Silicone Oil-free (1.40 ± 1.16 μL) syringes showed the lowest residual volume (p<0.001) in comparison to the others (range: 24.86 ± 1.78 μL for Injekt-F to 51.97 ± 3.37 μL for Omnifix-F). The most accurate setups were (percentage deviation from target volume): Zero Residual Silicone Oil-free (+0.70%), Zero Residual 0.3 mL (+4.49%), BD Ultra-Fine (+7.83%), Injekt-F (9.42%), Norm-Ject (+15.88%), Omnifix-F (+16.96%), BD Plastipak Brazil (+17.96%), and BD Plastipak Spain syringes (+19.41%). There was a statistically significant difference between the Zero Residual Silicone Oil-free syringe and all other syringes (p<0.0001), except for the Zero Residual 0.3 mL syringe (p=0.029). The coefficient of variation was low for all syringes. The modeled IOP rise ranged from 32.3 (SD 1.4) mmHg for 20-μL injection volume to 76.5 (SD 1.0) mmHg for 80-μL injection volume. For the standard 50-μL injection volume, the peak pressure was 50.7 (SD 0.1) mmHg, and the pressure rise duration was 28 (SD 2) minutes. There were significant differences in accuracy and residual volume between syringes, whereas they showed a high precision. Volume excess results in a considerable increase in IOP rise following injection. These findings may provide a relevant overview to clinicians and to both device and drug manufacturers regarding pharmacoeconomic, safety and efficacy issues.

Purpose: Standard automated perimetry (SAP) remains the gold standard functional test in glaucoma, used primarily for evaluating peripheral vision loss. Central contrast sensitivity (CCS) has emerged as a potential early functional marker of glaucomatous damage. This systematic review aimed to describe the different methods used to measure CCS in randomized controlled trials (RCT) involving glaucoma patients. Methods: We searched the MEDLINE, Embase, CINAHL, Cochrane Central Register of Controlled Trials, Epistemonikos, and ClinicalTrials.gov databases on 25 January 2023, and updated the search on 12 February 2025. Eligible studies comprised RCTs that reported CCS as an outcome in patients with glaucoma, suspected glaucoma, or ocular hypertension. No restrictions were placed on age, sex, ethnicity, geography, intervention, or publication year. Abstracts and full texts were screened independently by two reviewers. Descriptive statistics were used. No formal risk of bias assessment was performed, due to the descriptive nature of the review. Results: Of 1066 records screened, 31 studies met the eligibility criteria. The study sample size ranged from 7 to 207 (median: 23), with most studies involving primary open-angle glaucoma. Interventions were diverse, mainly involving topical medications, with timolol being the most frequent. Eleven CCS test methods were identified. Five studies did not report the method used. The CSV-1000 was the most commonly used test, being applied in 11 studies. Conclusions: CCS has been measured using a wide range of methods in glaucoma RCTs, with limited standardization. Most of the included studies were small, variably reported, and conducted over 10 years ago, suggesting a decreasing interest in CCS as an outcome measure in glaucoma RCTs. Funding: This review was funded by Oslo University Hospital and the Research Council of Norway. Registration: This review was registered on the OSF.