Background: The specialty-registration of independent prescribing (IP) was introduced for optometrists in 2008, which extended their roles including into acute ophthalmic services (AOS). The present study is the first since IP’s introduction to test concordance between IP optometrists and consultant ophthalmologists for diagnosis and management in AOS. Methods: The study ran prospectively for 2 years at Manchester Royal Eye Hospital (MREH). Each participant was individually assessed by an IP optometrist and then by the reference standard of a consultant ophthalmologist; diagnosis and management were recorded on separate, masked proformas. IP optometrists were compared to the reference standard in stages. Cases of disagreement were arbitrated by an independent consultant ophthalmologist. Cases where disagreement persisted after arbitration underwent consensus-review. Agreement was measured with percentages, and where possible kappa (Κ), for: diagnosis, prescribing decision, immediate management (interventions during assessment) and onward management (review, refer or discharge). Results: A total of 321 participants presented with 423 diagnoses. Agreement between all IP optometrists and the staged reference standard was as follows: ‘almost perfect’ for diagnosis (Κ = 0.882 ± 0.018), ‘substantial’ for prescribing decision (Κ = 0.745 ± 0.034) and ‘almost perfect’ for onward management (0.822 ± 0.032). Percentage-agreement between all IP optometrists and the staged reference standard per diagnosis was 82.0% (CI 78.1–85.4%), and per participant using stepwise weighting was 85.7% (CI 81.4–89.1%). Conclusions: Clinical decision-making in MREH’s AOS by experienced and appropriately trained IP optometrists is concordant with consultant ophthalmologists. This is the first study to explore and validate IP optometrists’ role in the high-risk field of AOS.