Study finds that current ophthalmic patient letters may pose comprehension difficulty

How accessible are the current notes patients receive from their eye care providers? A longitudinal analysis of patient notes administered by ophthalmologists, and those in related subspecialties, found that overall readability has decreased. Additionally, the analysis found that the majority of patient letters in the ophthalmology specialty are at a college reading level, which may make them difficult for patients to comprehend.¹

The study, published in BMJ Health & Informatics, included over 4 million patient letters–collected from January 2013 to November 2025 to assess the current state of readability in patient-physician correspondence. The analysis also discussed that certain ophthalmology subspecialties, such as neuro-ophthalmology, produce letters that are less accessible than others.¹

The study was led by Ariel Ong, MD, a National Institute for Health and Care Research Doctoral Fellow at University College London Institute of Ophthalmology.¹

Why is it important to establish a patient readability benchmark?

In April 2026, the Academy of Medical Royal Colleges updated their clinician guide for patient letters, titled “Please Write to Me” and by first author Hugh Rayner, MD.² The initial guide was published in 2018; however, compliance among physicians in the UK remains low.^1,3 Unlike other medical specialties, such as plastic and pediatrics, readability in ophthalmology subspecialties has not been studied at length. Ong and her team identified that a proper benchmark for establishing patient readability in ophthalmic clinical letters is necessary.¹

“Poorly readable clinical correspondence has direct patient-centered consequences—when letters are not written for the reader, they may undermine informed consent, shared decision-making, engagement and equitable access to care, thereby widening existing health disparities,“ the study authors stated.¹

While Rayner’s benchmark provides a thorough guide to make adjustments, many challenges exist that can make it difficult for physicians to tailor letters towards patients. Time, for example, can make it challenging for physicians to write an additional letter separate from their medical notes for a clinician audience. In addition to establishing the benchmark, Ong and her team discussed potential solutions to write patient-accessible letters in a timely and efficient manner.¹

Methods

For this study, researchers collected data from over 27 networked sites and aimed to capture a socioeconomically and ethnically diverse cohort. Letters were obtained from electronic health records (EHR) systems, and cover “the full spectrum of opthalmic subspecialties and opthalmology-adjacent services including orthoptics and optometry,” the study authors stated.¹

The study team employed a variety of scales to evaluate linguistic complexity among their cohort of patient letters. The primary scale applied was the Flesch Reading Ease (FRE) index, which provides a general estimate of textual difficulty based on sentence length and word complexity. Additionally, their study used Flesh-Kincaid Grade Level to assign a corresponding grade-level, adhering to the US grade-level system, based on FRE scores. Researchers also captured benchmarks such as mean characters per word, mean words per sentence, and the type-token ratio, which accounts for the number of distinct words to the total number of words. Additionally, their benchmark recorded the rate of second-person language (ie, “you,” “your,” “yours”) to assess whether letters were addressing patients directly.¹

Statistical analyses were conducted in Python. Each letter in the cohort was processed with the textstat library for standard readability. Specific linguistic and grammar/structural features were quantified with the spaCy natural language processing library.¹

Results

The research team collected 4,648,289 letters from 804,986 patients (median, 3; IQR, 1-6 letters per patient). The cohort had an overall median age of 53 (IQR: 31-69). Additionally, 52.5% of patients included were female; however, male patients had 1.9% more letters than female patients.¹ “Of the patients with available ethnicity data, White was the most common ethnicity, followed by other, Asian/Asian British, Black/Black British and Mixed,” the study authors stated. The study used the Index of Multiple Deprivation to measure socioeconomic status (median, 5; IQR, 3-7).

The median FRE score was 51.1 (IQR, 41.9-58.5), “indicating a substantially lower readability than the suggested reference range of 70-90 for patient facing materials,” the study authors stated.¹ FRE scores showed a declining trend throughout the 13-year timeline of the study (slope, -0.64 points/annum; P < .001). Letters from certain ophthalmology subspecialties saw improvement in readability, such as orthoptics (slope, +0.27 points/annum; P =.004).¹ While others, such as neuro-ophthalmology, saw a drastic decline in readability (slope, -1.24 points/annum; P < .001).

Potential solutions and study limitations

Ong and her team’s study assesses the largest cohort of clinical letters assembled to date.¹ Their study sheds light on the gaps in patient-clinician correspondence that exist in the field of ophthalmology, and offers potential solutions for implementation.

Based on the results of their study, the authors suggest implementing letter templates to help guide clinicians. This measure allows clinicians to “separate the medical record from the patient-facing explanation while keeping both aligned,” the study authors explained.¹ Moorfields and UCL Centre for Eye Health recommends their clinicians follow the “Please Write to Me” guidelines to produce quality patient letters. The authors note that their findings that readability scores decreased over time indicates the difficulty of applying policy changes to practice.¹

The authors also suggested the use of large language models (LLMs) to efficiently translate medical notes to patient-friendly language. Previous studies have found that the employment of LLMs in patient correspondence improves the translation of clinical text into patient-friendly language.^1,4 The application of LLMs could “potentially improve understanding and engagement without adding to clinician workload requiring clinicians to potentially compromise the clinical or legal completeness of their documentation,” as stated by the study authors. However, the authors acknowledge the potential risks of implementing an LLM, such as compromising patient privacy.¹

Another limitation of the study is the lack of author-level identifiers and assessment of variation in the linguistic cadence of individual clinicians. “To address this, we clustered letters using structural and lexical features as a data-driven proxy for writing style, so as to enable partial adjustment for unmeasured author-level heterogeneity” the study authors write.¹ The team also noted that institutional practice discrepancies in how patient letters are administered may exist, which are difficult to account for when retrieving the letters for EHR.

References

1. Ong A, Kiire C, Wagner S, Nguyen Q, Thomas P, Keane P. How well do we write for patients? Longitudinal analysis of the readability and complexity of 4.6 million ophthalmic clinical letters. BMJ Health & Care Informatics. 2026;33:e102086. doi:10.1136/bmjhci-2026-102086

2. Rayner H, Collins A, Anaokar M, et al. Please write to me: Guidance for writing directly to patients. Academy of Medical Royal Colleges. Updated April 2026. Accessed August 11, 2026. https://www.aomrc.org.uk/wp-content/uploads/2026/06/Please_write_to_me_update_130426.pdf

3. Sharp C, Staniland K, McMillan B, et al. Writing directly to patients, the time is now - but how? Rheumatology. 2024;63(7):1769–1771. doi:10.1093/rheumatology/keae093

4. Sumodhee D, Venning K, Mogul I, et al. A commentary on ophthalmic patients co-designing a new tool to better understand their hospital letters. Research Involvement and Engagement. 2025;11:25 doi:10.1186/s40900-025-00697-0