| Popis: |
Evaluate the differences between clinical visual acuity (VA) as recorded in medical records and electronic ETDRS (eETDRS) protocol VA measurements and factors affecting the size of the differences.Retrospective chart review.Study and fellow eyes of participants enrolled in DRCR Retina Network Protocols AC and AE (diabetic macular edema), and W (non-proliferative diabetic retinopathy) with clinical VA recorded within 3 months before the protocol visit.Linear mixed models evaluated the differences and their association with patient and ocular factors in univariable and multivariable models, with random effects for correlations within sites and participants.Difference between VA letter scores measured by eETDRS during a study protocol visit versus measured by Snellen during a regular clinical visit (Snellen fraction converted to eETDRS).Data from 1016 eyes (511 participants) across 74 sites were analyzed. The mean VA measurements were 68.6 letters (Snellen equivalent 20/50) at the clinical visit and 76.3 letters (Snellen equivalent 20/32) at the protocol visit, with a mean (standard deviation, SD) of 26 (21) days between visits. Mean (SD) protocol VA was better than clinical VA by 7.6 (9.6) letters overall, 10.7 (12.6) letters in eyes with clinical VA ≤20/50 (n = 376) and 5.8 (6.6) letters in eyes with clinical VA ≥20/40 (n = 640). On average, the difference between clinical and protocol VA was 1.3 letters smaller for every 1-line (5 letters) increase in clinical VA (p0.001). Mean (SD) differences by clinical correction of refractive error were 3.9 (9.0) letters with refraction, 6.9 (9.2) letters with glasses/contact lenses, 7.9 (11.5) letters with pinhole and 9.8 (9.3) letters without correction (p=0.06).On average, clinical Snellen VA is likely to be 1-2 lines worse than eETDRS protocol refraction and VA testing, which may partly explain why clinical practice does not always replicate clinical trial results. Eyes with lower clinical measurements and eyes tested without clinical refraction tended to have larger differences. Considering the potential discrepancies between clinical and protocol VA measurements, refracting eyes in the clinic may benefit patients when determining treatment plans and study referrals based on vision. |
