Statistical analysis
vision, lens, zero/very low vision, hyphaemia, trauma
ENDOPHTHALMITIS, RECRUITMENT, RETINAL DETACHMENT, LENS, MACULAR DISEASE, VITREOUS HAEMORRHAGE, REGRESSION, SCARRING, HYPHAEMIA
The target sample size for ASCOT was 300 patients (150 per arm) over a 3-and-a-half-year recruitment period. As actual recruitment rate was slower than projected, the recruitment period was extended to a total of 75 months; 280 eligible patients were recruited and all are included within this analysis.Baseline characteristics are summarised as mean (standard deviation—SD) for approximately normally distributed continuous variables or median (Interquartile range—IQR) where skewed. Categorical variables are summarised by frequencies and percentages. Descriptive data summaries are based on observations only and the number of missing observations are reported. The Pearson’s chi-squared test was used to assess seasonal variation in the injury numbers by month, and cause of injury.To explore the associations between baseline visual acuity (measured using an ETDRS chart at a starting distance of 4 m) and participant characteristics of interest, multivariable regression analyses were conducted. The clinically important characteristics of interest, informed by previous studies and study team clinical opinions were: previous primary repair, trauma classification, extent of trauma, previous eye surgery, macular disease, other historical ocular conditions, visual axial corneal scarring, hyphaemia, lens state, vitreous haemorrhage, endophthalmitis, retinal status and PVR. Given the high distribution of participants with an ETDRS score of 0 letters indicating very low/no vision, a zero-inflated Negative Binomial model was used to explore associations. This model incorporates two parts; (i) a logistic regression model that models the probability of zero/very low vision (ETDRS = 0) and (ii) a Negative Binomial model that models the amount of vision as measured by the ETDRS letter count score. The Negative Binomial model (part ii) included all the clinically important variables of interest. The logistic regression model (part i) used a subset of the clinically important variables that were first identified to be associated with zero vision (see Supplementary file Retinal detachment at baseline and associations between the clinically important characteristics of interest were explored in an additional analysis using a logistic regression model. Estimates from the logistic regression models are summarised as Odds Ratios (OR). Estimates from the zero-inflated Negative binomial model are presented as Incidence Rate Ratios (IRR) which represent the relative risk of a higher ETDRS score for the associated variable. Estimates are accompanied with 95% confidence intervals. A 