Discussion
detachments, iris abnormalities, cataract, Vitreous haemorrhage, ocular trauma, vitreous haemorrhage, retinal detachment, glaucoma, hyphaema, ocular co-morbidities, injuries, trauma
SCAR, POOR VISION, CATARACT, VITREOUS HAEMORRHAGE, ENDOPHTHALMITIS, MACULAR DISEASE, PATHOLOGY, DETACHMENTS, EYE DISEASE, RECRUITMENT, CORNEA, VITREOUS HAEMORRHAGE, RETINAL DETACHMENT, SCARRING, EYE, RECRUITMENT, LENS, HYPHAEMA, OPACITIES, GLAUCOMA, ANTERIOR
The ASCOT study was a prospective randomised controlled trial designed to test the efficacy of intraocular and periocular triamcinolone given at the time of vitrectomy surgery in cases of open globe injury. It recruited nationally in the UK from 27 sites. The baseline data therefore represents the cases considered suitable for inclusion by the principal investigators at the individual sites and is not a comprehensive epidemiological study on open globe injuries. Nevertheless, it provides detailed data on a large cohort of patients undergoing vitrectomy surgery.The study population were overwhelmingly (88%) male, consistent with other analyses of eye trauma epidemiology [There was a broad range of causal mechanisms of the injury in the study cases. The most common setting was the workplace (31%)followed by a significant number of the injuries (24%) due to interpersonal violence. In the UK, regulations relating to eye protection in the workplace are included in 1992 legislation on personal protective equipment at work, which came into effect in 1993 (recently updated in 2022 to also cover more causal employment relationships in addition to contracted employees) [The baseline clinical characteristics provide a useful insight into the range of pathology likely to be encountered by vitreoretinal surgeons. The initial view of the posterior segment is often compromised with 26% presenting with a visual axis corneal scar and 34% a hyphaema. Anterior segment pathology is likely with only 25% having a clear lens (35% had a cataract which may require combined surgery) and 60% having iris abnormalities. Vitreous haemorrhage was present in 66% with three-quarters of these being fundus obscuring. Approximately half of all patients had retinal detachment at the time of vitrectomy surgery with PVR already present in half of these. However, all patients in ASCOT were listed for vitrectomy, rather than being observed. The rapid development of PVR is notable, as the mean interval between injury and surgery was 20 days. The fovea was detached in over half (60%) of detachments.In the largest retrospective review to date of open globe injuries (848 patients), Andreoli et al. report that approximately 1/3 of patients (29%) proceed to vitrectomy surgery [Endophthalmitis was rare (2%) on presentation. Pre-existing eye disease was uncommon: four of the 280 patients had glaucoma and one had had previous macular disease recorded—this may reflect the younger age range of patients sustaining open globe eye trauma.The presenting clinical characteristics which were associated with better presenting vision were often related to ocular media opacities. The presence of corneal scarring, cataract, hyphaema and vitreous haemorrhage conferred less good presenting vision. Eyes which had previously undergone surgery also had less good vision possibly relating to more complex pre-existing intraocular pathology. Eyes with ACIOLs had better visual acuity – this may reflect a more longstanding and stable situation prior to the need for vitreoretinal intervention, however, this should be interpreted with caution as there were only two patients with ACIOLs. The presence of PVR (and by implication retinal detachment) on presentation was also associated with less good presenting vision. PVR is associated with poor vision and poor outcomes from surgery both with and without previous ocular trauma [The associations with retinal detachment at presentation are also notable. The zone of injury clearly influences the likelihood of retinal and vitreous involvement in the injury and as expected more posterior injuries were more likely to have retinal detachment on presentation. The association with hyphaema could potentially reflect the potential of intraocular blood to promote PVR through fibrogenic growth factors.Recruitment for the study was centred in London, particularly Moorfields Eye Hospital which was the lead site. The patient cohort is therefore not a comprehensive study of open globe injury in the UK. To compare regions, cases were grouped together to provide cohorts of a meaningful size for analysis. The cases recruited in London were generally less severe (a greater proportion of corneal, zone 1 (cornea), injuries) than elsewhere with more ocular co-morbidities. These observations must, however, be treated with caution as they may be influenced by recruitment bias in the trial centres.There was a trend for recruitment to be higher in spring (March and April) and October although this was not statistically significant with the patient numbers in the study. Notably workplace injuries had a trend to more common in spring and summer with interpersonal violence being more common in January and December. It is possible that a reduction in work and an increase in in social interaction results in the reversal of causation seen in December and January. Although a bias in case recruitment may influence the monthly cases numbers overall, it is unlikely to have affected the variation in injury causation seen.