Fovea-off retinal detachments
Older studies reported better visual outcomes for fovea-off RRDs operated within a week of LCV18–21; however, the exact timing of repair during this first week did not seem to effect visual results.3 22 23 The results of these studies led to recommendations that patients with fovea-off RRDs were placed on a routine surgical list within the week rather than being considered for more urgent treatment. Patients in those studies were treated with scleral buckling (SB) surgery22 23 or by a mixture of surgical methods including pneumatic retinopexy, SB, pars-plana vitrectomy (PPV) and combined PPV+SB.3
Subsequent studies on visual outcome following mainly PPV for macula-off RRDs found that visual prognosis was better if the surgery was carried out within 3 days of LCV.15 16 A systematic review and meta-analysis published in 2014 on the impact of duration of macula-off RRD on visual outcome found improved visual results if SB surgery was undertaken within 3 days; however, the limited amount of data precluded a meta-analysis of the results following PPV.1
In 2021, the largest study to date was published, including 1482 patients with fovea-off RRD with a recorded duration of LCV and of whom the vast majority were treated by PPV with gas tamponade.2 The study found that patients were more likely to achieve a postoperative best-corrected visual acuity (BCVA) of ≤0.30 logMAR (Snellen ≥6/12) if operated relatively early after LCV: 83.5% if treated ≤2 days, 76.1% for 3–4 days and 68.7% for 5–7 days. In this study, preoperative BCVA was better in eyes with ≤2 days duration of LCV, and although the height of foveal elevation was not considered, it has previously been established that preoperative BCVA is directly related to the height of foveal detachment.24 This suggests that the foveal elevation may have been lower in patients in the ≤2 days group than in those with longer duration of LCV. Independently of duration, the height of foveal detachment has been shown as predictive factor for postoperative BCVA3–5 and as such may have contributed to the better visual outcome in patients with a shorter duration of LCV.
Haq et al25 found an improved visual outcome for patients with fovea-off RRD when operated within 1 day of presentation as compared with after 2 or more days. This period, however, referred to the time of diagnosis and not to the time point of LCV. Furthermore, they found no difference in the visual outcome between the fovea-on and fovea-splitting groups. While the true duration of these fovea-splitting status cases was unknown, the height of foveal elevation in foveal-splitting cases is very low, likely explaining the result.
It is unlikely that the duration of foveal elevation is the sole factor determining postoperative visual recovery. Patients following RRD repair by SB quite frequently show shallow persistent foveal detachment sometimes lasting for several weeks or months. There is no consensus in the literature, but several studies comparing visual outcomes of patients with and without persistent subfoveal fluid have not demonstrated a deleterious influence on final visual acuity after reabsorption of the subfoveal fluid bleb.26–29 For example, Seo et al26 recorded persistent subfoveal fluid on optical coherence tomography (OCT) 1 month after surgery in 23 of 44 eyes, which disappeared in 12 of these eyes within 6 months postoperatively and in the other 11 eyes between 6 and 12 months postoperatively. Mean subfoveal fluid heights were reported as being relatively stable at approximately 100 µm (range 104–135) until the fluid disappeared. Final logMAR BCVA was 0.22 (SD 0.16) in the group with foveal detachment that resolved within 12 months compared with 0.18 (SD 0.17) in those without foveal detachment at 1 month postoperatively (p=0.42).
Several studies have demonstrated better visual outcomes for RRDs with lower macular detachment height,3–5 17 measured either by ultrasound3 4 or OCT5 17 when the surgical techniques were mixed, for example, SB and PPV,3 4 17 or when surgical repair was done exclusively by PPV with gas tamponade.5 Two studies considered both the height of macular elevation (on ultrasound) or foveal elevation (on OCT) and the duration of LCV, up to a maximum of 7 days. They found that the lower the height of fluid, the better the visual acuity outcome which was independent of the duration of LCV.3 5
The evidence currently available indicates that once the fovea is involved in the RRD, factors negatively associated with functional recovery include worse preoperative visual acuity, older age, female gender, duration and height of foveal detachment, the presence of proliferative vitreoretinopathy (PVR) grade C, and total retinal detachment.2–5 17 23 30–33 It is important to note, however, that the only modifiable factors are duration and height of foveal elevation. Prompt surgery will shorten the duration that the fovea remains detached and preoperative posturing and/or bilateral eye patching can prevent an increase in foveal detachment height and in some cases reduce it.8 11
In particular, at least within the first week of foveal elevation, every day is significant.2 A patient presenting with a 2-week history of LVC, for example, is less acute than someone with a 4-day history. For longer than 1-week duration of LCV, the point where improvement in visual recovery is minimal or ceases is not clear. The visual prognosis for patients with LCV >28 days has been shown to be worse than those within 13–28 days,2 so time remains important at least up to 28 days.
