Letters sent to patients after ophthalmology appointments are often written at a level that many people may struggle to understand, according to the largest analysis yet of clinical correspondence in the UK. Researchers examined more than 4.6 million outpatient letters produced over 12 years and found that most were significantly more complex than recommended for patient-facing information. The findings raise concerns about whether routine medical communication is meeting national expectations for clarity, accessibility and patient-centred care.
The study, published in BMJ Health & Care Informatics, focused on ophthalmology, the UK’s busiest outpatient specialty. The researchers analysed letters sent between 2013 and 2025 to 804,986 patients attending 17 different ophthalmology subspecialty services within a large UK hospital trust. The letters covered a wide range of eye-care services and provided an unusually broad view of how clinicians communicate with patients over time.
On average, the letters recorded a Flesch Reading Ease score of 51.1. The Flesch system estimates how difficult a text is to read by examining factors such as sentence length and the number of syllables in words. Higher scores indicate easier reading, while lower scores indicate greater complexity. A score around 51 generally corresponds to college-level comprehension, placing the letters above the reading level typically recommended for information intended for the general public. Overall, 95% of the letters were less readable than the recommended standard for patient materials.
Although readability scores cannot capture every aspect of communication, they offer a useful technical measure of linguistic burden. Long sentences, dense paragraphs, passive constructions and specialised medical vocabulary can all make information more difficult to process. For patients managing sight loss, chronic eye disease, anxiety or limited health literacy, the challenge may be even greater. A letter can therefore be factually accurate while still failing to communicate its meaning effectively to the person expected to read it.
The results also revealed marked differences between ophthalmology subspecialties. Letters from paediatrics, optometry and orthoptics were, on average, easier to read than correspondence from several other services. The researchers suggest that the difference may reflect variations in clinical culture, documentation practices and the use of structured templates. In children’s eye services, letters are often written for parents or caregivers, which may naturally encourage more direct and accessible language. Templates used in optometry and orthoptics may also reduce variation and make it easier for clinicians to follow a consistent structure.
The analysis found that letters were rarely written directly to patients, despite guidance encouraging clinicians to do so. Only slightly more than 2% of the correspondence was addressed to patients in direct terms, and the personal pronoun “you” appeared infrequently. This suggests that many letters may still be written primarily as professional communications between clinicians, with patients receiving a copy rather than being treated as the main audience. The researchers observed a small increase in direct address over the study period, but the overall proportion remained very low.
The findings are significant because outpatient letters perform two jobs at once. They must function as formal medical records containing diagnoses, test results, treatment decisions and follow-up plans, while also explaining that information to patients and supporting communication with GPs and other healthcare professionals. Medical terminology can be precise and efficient for clinicians, but it may be unfamiliar or confusing to patients. Time pressure, electronic record systems and local documentation requirements can make the task of producing two clearly differentiated forms of communication even more difficult.
UK guidance has increasingly called for clinicians to write directly to patients rather than writing about them. Recommendations from the Academy of Medical Royal Colleges in 2018 encouraged a more patient-centred style, while NHS England has described clear and timely communication as essential to effective outpatient care. Yet the new analysis points to a persistent gap between those policies and everyday practice. The researchers argue that improving clinical letters may require more than asking individual doctors to simplify their writing; electronic templates, automated readability feedback and service-level training could also play a role.
The study has important limitations. Because the researchers analysed large-scale linguistic patterns, they could not determine how individual clinicians differed or whether patients actually misunderstood particular letters. Readability formulas measure text structure rather than empathy, accuracy, cultural appropriateness or the clinical consequences of misunderstanding. The method used to identify the intended audience may not perfectly reflect how letters were used in practice, and changes in record-keeping systems, clinical workflows and institutional policies may have influenced the results. Even so, the researchers describe the work as the first long-term, population-scale evaluation of outpatient clinic letter readability over more than a decade.
They conclude that poor readability is widespread, has become worse over time and varies substantially between services, revealing system-level patterns that had previously been difficult to quantify. The challenge now is to preserve the precision required in a medical record while making information understandable to the person whose health is being discussed. The researchers say targeted interventions and innovative communication tools could help close the gap between policy and practice, ensuring that an ophthalmology letter is not merely recorded in a patient’s file but genuinely understood by the patient.
Subject of Research: People
Article Title: How well do we write for patients? Longitudinal analysis of the readability and complexity of 4.6 million ophthalmic clinical letters
News Publication Date: 4-Aug-2026
Web References: https://doi.org/10.1136/bmjhci-2026-102086
References: BMJ Health & Care Informatics, observational study, DOI: 10.1136/bmjhci-2026-102086
Keywords: ophthalmology, patient communication, clinical letters, readability, health literacy, medical terminology, outpatient care, healthcare informatics, patient-centred care, Flesch Reading Ease
