The ageing global population is expected to more than double by 2050, with a parallel increase in vision impairment and blindness 1. Vision loss is among the top causes of years lived with disability in older adults, with significant impacts on quality of life, independence, and mortality 2. Early detection of common vision-threatening conditions such as cataract, glaucoma, age-related macular degeneration (AMD), and diabetic retinopathy (DR) is crucial to support healthy ageing 3. However, the current eye care model which primarily relies on specialist-delivered care is unlikely to meet future eye care demands. As such, various countries have explored hybrid care models between ophthalmologists and optometrists. In Singapore, the Primary Eye Care (PEC) model, a community-based eye care service, was introduced in 2018 to shift the care of patients with stable, non-complex eye conditions to the community by training optometrists to manage these cases. A national referral guideline, jointly developed and endorsed by ophthalmologists, guides appropriate referrals to PEC. Yet, there is limited evidence on the quality of care and the factors influencing implementation. We conducted a mixed-methods study to evaluate the PEC model. First, we assessed concordance in management plans between PEC optometrists and ophthalmologists. Second, we explored contextual factors underpinning care quality to inform future scale-up. A sequential explanatory design guided by the practical, robust implementation and sustainability model (PRISM) framework was adopted to achieve the aims. Quantitatively, 31,076 PEC cases from January 2018 to January 2024 were reviewed. For patients with cataract, DR, AMD, or suspected glaucoma, ophthalmologists independently reviewed structured and unstructured records (including clinical notes and imaging) to assess agreement with optometrists' care plans. We calculated overall concordance, Cohen's kappa for follow-up location and duration, and rates of false positives and negatives to measure PEC's care quality. Qualitatively, we conducted in-depth interviews and focus group discussions with 12 healthcare professionals, including optometrists, ophthalmologists, and the PEC model director. The interview guide was informed by literature, the PRISM framework, clinical observations, and preliminary quantitative results. Data were analysed thematically using an inductive approach. Integration occurred at two points: quantitative findings were used to inform the interview guide, and results were merged to explore points of convergence and divergence. This study adhered to the Declaration of Helsinki and was approved by the research ethics committee of the National Healthcare Group. Written informed consent was obtained from all interviewees prior to study participation. The overall concordance rate between optometrists and ophthalmologists was 95.6% (28,615/29,926), with a Cohen's kappa of 0.97 for follow-up location and 0.92 for follow-up duration. False positive and negative rates ranged from 11.6% to 33.3%, and the highest discordance was observed in suspected glaucoma cases (11.4%) (Tables 1 and 2). This study is among the first to evaluate the quality of care within a community-based setting where optometrists are positioned as the primary eye care providers, and to explore the key drivers that contributed to its effectiveness. High concordance rates between optometrists and ophthalmologists highlighted the high-quality care provided. Underpinning this is strong leadership support (continued endorsement from department leaders for optometrists' role expansion), a structured training programme, standardised clinical guidelines, and a real-time ophthalmologist helpline. These foundational elements were further reinforced by the optometrists' commitment to continuous learning and open interdisciplinary communication. Importantly, sustaining high-quality care extended beyond these structural components. Fostering interprofessional trust, enabling responsibility transfer (e.g., referral of patients with stable and non-complex eye conditions to optometrists at PEC), and normalising collaboration, these critical mechanisms will contribute to the long-term viability of this care model. Our study aligned with findings from international literature which emphasised the importance of these structural components and mechanisms for the successful and sustainable transition of stable, non-complex eye conditions from ophthalmologist-managed care to primary care delivered by specially trained optometrists 4, 5. PEC optometrists reported that glaucoma diagnosis is challenging due to diagnostic tests variability and physiological variations in optic nerve morphology, especially in early stages. These factors contributed to higher discordance in suspected glaucoma management. Hence, optometrists highlighted the value of additional exposure to glaucoma cases during training. This was seen as a potential strategy, especially for junior optometrists, to enhance diagnostic and management plan confidence for future clinical decision-making. Our qualitative findings also suggested that discordance in the management of glaucoma suspects may be partly attributed to the differences between ophthalmologists' clinical judgements and the national clinical guideline. Specifically, ophthalmologists' training background and years of experience influenced the interpretation of diagnostic results and the formulation of management plans. The national clinical guideline is jointly developed and endorsed by ophthalmologists across the public hospitals in Singapore for PEC. The national clinical guideline adopted a conservative approach, for example, recommending a referral to an ophthalmologist for particular clinical findings. However, a more experienced ophthalmologist may determine that community-based follow-up is sufficient for the same clinical findings, thus resulting in discordance between the guideline-based recommendation and actual clinical decision making. This is also reflected in our quantitative data, where optometrists, guided by the guideline, tended to adopt a more cautious approach as reflected in the higher proportion of false positives (15 cases; 41.7%) compared to false negatives (10 cases; 27.8%). This trend is also observed across all the cases. The percentage of false positive for follow-up duration is higher compared to false negative, reflecting a more conservative approach adopted by the optometrists. While this practice prioritises patient safety, it contributed to the observed discordance rate in glaucoma suspects. In the current study, concordance between ophthalmologists was not assessed While ophthalmologists independently assessed each clinical case, they were not blinded to the optometrists' management plan. Future evaluations should include inter-ophthalmologist concordance, and the optometrists' management plan should be masked to better interpret the agreement between the concordance of optometrists and ophthalmologists. Additionally, missed pathology and visual acuity outcomes were not collected as part of this study. Future studies could include these outcomes as a proxy of quality care. In summary, our findings highlighted that with key structures and mechanisms in place, PEC can effectively support the healthcare system in meeting growing eye care demand. By caring for patients with stable non-complex conditions in the community, PEC can help to optimise ophthalmologists' capacity for patients with urgent and complex eye conditions. The authors declare no conflicts of interest. The data that support the findings of this study are available from the corresponding author upon reasonable request.
Yip et al. (Tue,) studied this question.