Distance word acuity, critical print size and driving vision standards

Visual Demand and Acuity Reserve of Chinese versus English Newspapers

SIGNIFICANCE

This study suggests that Chinese newspaper characters are more legible than English newspaper letters. Characters in Chinese newspapers have higher acuity reserve than English newspapers.

PURPOSE

The purpose of this study was to evaluate visual demand and acuity reserve for Chinese newspapers in comparison with published data on U.S. newspapers.

METHODS

The test distances for visual acuity in Chinese clinical studies were reviewed systematically. Characters from different sections of newspapers printed in simplified Chinese were evaluated. The character height, frequency, and visual demand and acuity reserve of each newspaper section were determined for Chinese characters of the six different levels of complexity.

RESULTS

More than 70% of Chinese clinical studies measure near visual acuity at either 33 or 40 cm. The height of Chinese characters ranged from 1.95 to 3.28 mm across different sections of five newspapers compared with 1.0 to 2.0 mm for English letters. The frequency of Chinese characters from least to most complex ranged from 7 to 34% across 12 sections of one Chinese newspaper. The angular threshold across the six complexity levels of Chinese characters ranged from 4.62 to 5.93 arcmin (0.54 to 0.69 mm at 40-cm reading distance) with a weighted angular threshold of 5.18 arcmin compared with 3.37 arcmin (0.39 mm) for the English letters. For Chinese newspapers, at 40-cm reading distance, the acuity reserve for the smallest and largest median size was 3.55 and 4.61, respectively.

CONCLUSIONS

Chinese characters are larger than English characters in all newspaper sections newspapers by a factor of 1.60 to 2.34. Given that Chinese characters need to be 1.54 times larger than English letters to provide the same acuity reserve, on average, Chinese newspapers are more legible than U.S. English newspapers.

Individualizing Therapy for Neovascular Age-Related Macular Degeneration with Aflibercept (VITAL): A Two-Year Prospective, Interventional Single-Centre Trial

AIMS

To report the mean change in Early Treatment Diabetic Retinopathy Study (ETDRS) best-corrected visual acuity (BCVA) and reading performance (reading acuity and maximum reading speed (MRS) using the MNREAD test) between baseline and 24 months in treatment-naïve patients with neovascular age-related macular degeneration (nAMD) treated with intravitreal aflibercept injections.

METHODS

A prospective, open-label, interventional non-randomised case series with 24 months' duration. Patients were recruited to the study from medical retina clinics at Moorfields Eye Hospital. Intravitreal injections of 2.0 mg aflibercept in the study eye were administered using a fixed dosing regimen during the first year and a treat-and-extend treatment regimen during the second year of treatment.

RESULTS

Fifty patients were enrolled with a mean age (SD) of 78.7 (7.6) years; a mean BCVA of 62.8 ETDRS letters; mean reading acuity of 0.52 logMAR; mean maximum reading speed (MRS) of 141.3 words per minute and a central macular thickness of 322.6 µm at baseline. The mean improvement in BCVA was 6.4 letters for the 44 patients (88%) for whom data was available at 2 years. The mean improvement in reading acuity was 0.13 logMAR with an improvement in MRS of 2.9 words per minute. The mean reduction in CRT from baseline was 104.8 µm.

CONCLUSIONS

Aflibercept treatment of nAMD using fixed dosing in year 1 and treat and extend in year 2 leads to improvements in reading ability, visual acuity and retinal morphology which were maintained to 2 years of treatment.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT02441816, the VITAL study.

SIERRA-AMD: A Retrospective, Real-World Evidence Study of Patients with Neovascular Age-Related Macular Degeneration in the United States

PURPOSE

Characterize real-world baseline visual acuity (VA) and anti-vascular endothelial growth factor (VEGF) treatment patterns in neovascular age-related macular degeneration patients in 2012-2015.

DESIGN

Retrospective, multicenter, noninterventional real-world evidence study.

PARTICIPANTS

A total of 98 821 eyes from 79 885 patients receiving intravitreal anti-VEGF therapy.

METHODS

Anonymized patient data routinely collected over 5 years were extracted from 58 United States centers to a central database using an electronic medical records system.

MAIN OUTCOME MEASURES

Baseline VA, VA change from baseline, treatment frequencies, annual anti-VEGF injections, bilateral treatment frequencies, annual total clinic visits, and noninjection clinic visits.

RESULTS

Baseline characteristics were comparable across years. Baseline VAs (Mean±standard deviation [SD] Early Treatment Diabetic Retinopathy Study [ETDRS] letters) were similar for 2012, 2013, and 2014 (53.6±23.3, 53.2±23.4, and 53.1±23.6, respectively), but was lower for 2015 (50.7±24.4). In eyes with 4-year follow-up, VA changes from baseline (ETDRS letters) were least squares means of +1.1 (95% confidence interval [CI], 1.0;1.3), -1.3 (95%CI, -1.5;-1.0), and -3.1 (95%CI, -3.5;-2.7), and -5.2 (95%CI, -6.0;-4.3) for years 1-4. Mean±SD number of injections was 7.5±1.9, 6.7±2.1, 6.6±2.3, and 6.4±2.3 for years 1-4. By year 4, 36.7% of eyes had ≤8-week dosing intervals (q8w) and 21.2% had ≥12-week dosing intervals. Eyes treated q8w increased 40% from Year 1 (32.4%) to Year 4 (45.3%). Baseline bilateral treatment frequency was 6.1%. Of the patients treated bilaterally, 32.0% received the first treatment in the better-seeing eye, and 68.0% received first treatment in an eye with vision the same as or worse than the fellow-eye. This trend was evident across all index years.

CONCLUSIONS

This real-world study describes the treatment burden, initiation and monitoring patterns, and VA outcomes at a scale and timeframe that has not been previously reported. In this cohort, baseline VA was similar for the index years 2012-2014, but lower for 2015. In patients with 4-year follow-up, both VA and injection frequency declined, whereas the proportion of eyes treated more frequently than the recommended q8w interval increased. The reduction in dosing intervals may be a consequence of intensification of treatment due to year-on-year VA loss and disease progression.

Impact of varying the definition of myopia on estimates of prevalence and associations with risk factors: time for an approach that serves research, practice and policy

BACKGROUND

Refractive error is an increasing global public health concern that requires robust and reliable research to identify modifiable risk factors and provide accurate estimates of population burden. We investigated the impact of reclassification of individuals when using different threshold values of spherical equivalent (SE) to define myopia, on estimates of frequency, distribution and associations with risk factors, to inform current international initiatives to standardise definitions.

METHODS

A random sample of 1985 individuals from the 1958 British birth cohort, at age 44, had autorefraction and self-reported on educational attainment and social class.Refraction status assigned in three different models using SE: (A) moderate to high myopia -3 diopters (D) or more extreme (≤-3.00D), (B) hypermetropia +1.00D or more extreme (≥+1.00D) and (C) mild myopia using three different thresholds: -1.00D, -0.75D or -0.50D, hence reciprocal changes in definition of emmetropia.

RESULTS

Frequency estimates and associations with risk factors altered significantly as the threshold value for myopia moved towards SE 0.0D: prevalence of mild myopia increased from 28% to 47%, the association with highest educational attainment attenuated and with higher social class strengthened, with changes in risk ratios of approximately 20%.

CONCLUSION

Even small changes in the threshold definition of myopia (±0.25D) can significantly affect the conclusions of epidemiological studies, creating both false-positive and false-negative associations for specific risk factors. An international classification for refractive error, empirically evidenced and cognisant of the question(s) being addressed and the population(s) being studied, is needed to serve better translational research, practice and policy.

Scientific Posters: A Plea from a Conference Attendee

Conferences provide lots of opportunities to learn and poster sessions are supposed to be one of these venues. However, it seems most posters are not designed considering the reader or the venue; they are designed to reflect a potential manuscript. In this commentary, I provide a rationale why posters should be an illustrated abstract and provide some design tips to make the poster more reader friendly based on available research.