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OP-04 Clinical use of comfortable print size (CfPS)
  1. Keziah Latham
  1. Anglia Ruskin University, Cambridge, UK


Introduction Assessment of reading function is key to providing solutions to difficulties with reading for people with sight loss, with reading performance at print sizes larger than acuity threshold particularly important to understand. Critical print size (CPS), reflecting the smallest size supporting maximum reading speed, is valuable but time consuming to measure. Applying a ‘reserve’ to acuity threshold (often 2:1) is quicker but does not reflect individual variation. Is there a clinically efficient way of identifying print size allowing maximum reading speed on an individual basis?

Aims To introduce comfortable print size (CfPS), compare it to existing alternatives, and consider its utility in visual assessment.

Methods Results are presented from two cohorts with self-reported visual loss affecting daily life. All reading assessments were conducted using the MNREAD. CfPS was assessed by asking ‘What is the smallest print size that you would find comfortable using?’ CPS and reading acuity were established for MNREAD chart and app.

Results There is little clinical difference between CPS and CfPS, with a maximum mean difference of 0.1logMAR between CfPS and different assessments of CPS.

Repeatability of CfPS within a session is ±0.09logMAR. CfPS is quicker to assess (median 131sec) than CPS with the app (284sec) or chart (185sec excluding graph plotting).

Conclusion CfPS is similar to CPS, repeatable (within session), quick to assess, and provides an individualised measure. Its clinical use will be discussed.

This is an open access article distributed in accordance with the Creative Commons Attribution 4.0 Unported (CC BY 4.0) license, which permits others to copy, redistribute, remix, transform and build upon this work for any purpose, provided the original work is properly cited, a link to the licence is given, and indication of whether changes were made. See:

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