Discussion
Acute, fovea-involving, dense submacular haemorrhage may result from a variety of underlying disease processes and result in profound vision loss if untreated. These results suggest some visual improvement following PPV with subretinal tPA and pneumatic displacement in most patients, regardless of the cause of SRMH. While prior studies have generally been limited to exudative AMD, this study includes all patients with SRMH regardless of underlying diagnosis. Prior wet AMD series have demonstrated modest visual recovery, anatomic success and relatively few adverse events.7–11 Some natural history studies have suggested worse outcomes of SRMH in patients with CNV, while interventional studies have demonstrated improved outcomes in patients continuing to receive anti-VEGF treatments post-operatively.4 9 This would suggest that it is prudent to continue anti-VEGF treatment postoperatively in patients with CNV.
Visual outcomes in our patients are like those previously reported in several exudative AMD studies,7 8 11 and had greater improvement than in others.9 10 One study by Gonzalez-Lopez et al reported slightly better outcomes with intervention earlier than 8 days, worse outcomes by area of haemorrhage and a similar overall final BCVA to this cohort at roughly 12-month follow-up.12 More than half of our patients gained vision, with 41.7% of patients gaining significant vision of 3 or more lines at 3 months (figure 1A,B). Complications following intervention included vitreous haemorrhage, recurrent submacular haemorrhage, rhegmatogenous retinal detachment, glaucoma, corneal blood staining and phthisis, equal to or less frequent than previous reports.7–9 11 The mean and median times to surgery were 14.6 and 11 days, respectively, usually due to delay by patients in seeking evaluation, or referral delay from outside institutions in the community. Whether future studies demonstrate correlation between earlier intervention and improved visual outcome remains to be seen.
While follow-up was variable long term, it was excellent for our primary intervals of interest, with 36/37 patients followed to 3 months. Given that many of these patients will likely continue to gradually lose vision due to the natural course of their diseases, a more conservative follow-up period was considered appropriate when evaluating results of surgical intervention alone. We did not analyse the BCVA at 1-month follow-up for our secondary outcomes since presence of intraocular gas will greatly limit interpretation. Additionally, a 3-month follow-up was chosen because of prior studies published with positive results at this interval, and this shorter interval limits confounding from usual progression of disease.8 9 11 Of the patients diagnosed with ‘undifferentiated CNV’, 4/8 were suspected to have PCV but either lacked sufficient preoperative and postoperative testing (fluorescein angiography and/or indocyanine green angiography), or else had equivocal testing. Since the referral pattern of the institution includes a walk-in ‘eye emergency department’, a significant proportion of these patients were first-time visits, and have no data prior to acute SRMH including baseline vision prior to the event.
Neither anatomic location nor height of haemorrhage as determined by preoperative OCT were found to be of significant prognostic value, though this study is likely underpowered to find such an effect (figure 2A,B). Preoperative OCT was often not available for patients referred from outside institutions or satellite facilities. From our total patient cohort, 24/37 had preoperative OCT available. A large, retrospective study by Treumer et al also reported no correlation between preoperative height of haemorrhage on OCT, with a total of 132 eyes having a very similar final BCVA of 1.0 logMAR compared with 1.09 logMAR in this cohort.13 Our other secondary outcome, a subgroup analysis of the relationship VA to underlying diagnosis, failed to reveal any statistical preference. This suggests that this treatment may be a viable option for all causes of dense, fovea-involving SRMH, regardless of aetiology. Caution is advised in interpreting these results, however, due to small numbers within subgroups. While this study lacks sufficient preoperative baseline VA data, it is likely that patients with poor baseline VA may expect more limited improvement. Common reasons for missing baseline acuity included first time presentation to the eye emergency department without history of evaluation, or referral from outside facility without available historical data. Of the 14 patients with baseline VA data available, the worst preoperative VA documented was 20/200 in two patients (range 20/20 to 20/200). Both patients worsened to counting fingers vision at 3 months, and did not improve at final follow-up.
The strengths of this study are that it includes a relatively large and diverse group of aetiologies with a common diagnosis, compared with prior studies limited solely to patients with exudative AMD. While we were not able to find significant differences in outcome between disease groups, a prospective, randomised study in the future may detect differences which will help predict expected patient outcomes. In concordance with natural history studies, we hypothesise that patients without underlying CNV (proliferativediabetic retinopathy, vein occlusion, macroaneurysm, among others) may ultimately have a better prognosis. Retrospective studies in populations with variable follow-up may be misleading and subject to a ‘loss to follow-up’ bias.14 The focus on interval data reported proportions of patients achieving specific visual gains at specific points postoperatively, allowing us to avoid the impact of variable follow-up. Additionally, for real-world, retrospective data of this nature, contiguous interval windows allow a more rigorous way to classify follow-up intervals. Nonetheless, several limitations of this study are important and must be considered. The retrospective and non-randomised nature of the patients included may be subject to a form of selection bias. Patients with less severe presentations may have been managed with conservative measures such as intravitreal injections, while patients with the more severe haemorrhage and poorer prognosis may have been deemed surgical candidates. If this were the case, patients would potentially be negatively skewed toward those with worse haemorrhages at presentation. In addition, given the referral pattern at our facility, we often did not have preoperative imaging or baseline VA data at time of presentation. Possibly, in some of those patients with unknown baseline vision, postoperative change interpreted as improvement may have regression to their presurgical acuity. Considering prior natural history studies, as well as our own longitudinal experiences, the authors feel that this data is compelling, and suggests that most patients with such a vision-threatening condition derive some benefit from this form of surgical intervention.
