Article

The retinal detachment decision

Clarifying the grey area between ‘urgency’ and ‘emergency.’

In clinical medicine, emergencies are usually thought of as situations in which physicians and other providers should “drop everything” and attend to the problem at hand. But, in ophthalmology, we see few true emergencies. For example, acute endophthalmitis is an emergency in which delay of treatment can mean a worse outcome for the patient. In some other scenarios, the considerations are not as clear-cut.

Rhegmatogenous retinal detachment (RRD) is a condition that falls into this grey area between emergency and urgent, but less time-sensitive. An understanding of how to manage RRD is particularly important, as 28,000 U.S. patients are affected per year.1 The outcome of this surgical condition is based on many clinical factors. Perhaps the most important: whether the macula is attached (on) or detached (off) at the time of repair.

MACULA-ON RRD

Subretinal fluid and risk

Since macula-on RRD has a better prognosis than macula-off RRD, a main goal in management is to treat the former before it converts to the latter.2,3 This requires understanding of two simple questions: how quickly does macula-on RRD progress to macula-off RRD, and which patients are at greatest risk for progression?

The movement of subretinal fluid can be dynamic. Patients experience episodes of progression and regression, although generally detachments tend to increase with time. Two reports showed that approximately 20% of the detachments (nine out of 50 in one report, 23 out of 116 in another)4,5 had a net increase of fluid during admission. One multicenter prospective observational study (Macula-On Retinal Detachment, or MORD, study), involving 15 ophthalmic units in the United Kingdom reported a mean rate of subretinal fluid progression of 1.8-disc diameters per day. Most of the patients in this series did not show rapid progression, and the only significant parameter associated with the distance of subretinal fluid to the fovea at surgery was the distance of subretinal fluid from the fovea at the presentation. Essentially, the closer the subretinal fluid was to the fovea at first examination, the higher risk of progressing to macula-off RRD.6

The repair time factor

Most concerning — and perhaps most instructive — are those detachments that progress to macula-off after presenting for treatment. The rate of this occurrence ranges from 0.5%7 to nearly 10%.5 In a series from Bascom Palmer Eye Institute reporting the lowest progression rate, only one out of 199 eyes progressed to macula-off after presentation for ophthalmic care. All patients in this series underwent scleral buckle surgery for primary fovea-sparing RRD, with more than 80% receiving treatment within 72 hours. One patient with a superior detachment progressed to macula-off when surgery was not performed within the first four days from presentation. No significant difference in visual outcome was found when the time from presentation to repair was 0 to four hours, four to 12 hours, 12 to 24 hours or 24 to 72 hours.7

We reviewed a series of 96 macula-on RRDs managed at University of California, San Francisco to determine whether doing surgery on the same day or the next day made a difference in outcomes when managing macula-on RRD (Figure 1, page 32). In this group of 43 cases operated on the same day, 45 the next day and eight two days later, we found no statistically significant difference in visual outcomes among the groups. Only one case (approximately 1%) progressed to macula-off between presentation and the time of surgery; this occurred in a superior bullous RRD in the setting of lattice and high myopia. We identified some possible drawbacks to same-day surgery, such as longer time in the operating room (2.98±0.46 hours) compared to next-day surgery (2.54±0.38 hours), even when factoring in the type of surgery performed.8

Figure 1. Inferior macula-on rhegmatogenous retinal detachment in a 26-year-old woman with superior visual field defect noted on routine examination.

Several other studies have reported similarly small rates of progression to macula-off RRD after presentation. A study from Glostrup Hospital in Denmark in which cases were observed for up to 72 hours before surgery found that one of 96 patients progressed to macula-off: a patient with a bullous pseudophakic retinal detachment about nine hours after presentation.4

At St. Thomas’ Hospital in the UK, 10 of 930 patients (1.1%) progressed to macula-off in the first five days. Nine of the 10 were superotemporal RRD extending to at least the vascular arcade at presentation.9 Another series from the University of Auckland, New Zealand, confirmed an average rate of progression around 1.4%; two of 144 patients occurred between 12 to 24 hours after presentation, and both were similar in featuring superior bullous detachment at the first examination.10 In the one series that reported a higher rate of progression to macula-off (from Georg-August University in Germany), 11 of 116 patients (9.5%) progressed, but the authors report that one-third of patients in the study had a bullous RRD at presentation.5

Urgent but not emergent?

Based on these findings, it seems that patients at highest risk for progression to macula-off are those with superior, bullous RRD with greater posterior extent.4,5,8-10 A significant delay in initiating surgery may also be a risk factor.4

On the other hand, considerations such as surgeon fatigue, a lack of availability of the surgeon’s usual staff or equipment, or inadequate management of coexisting medical conditions have been found to lead to worse outcomes in surgery in general and could argue against “rushing” the patient to the operating room under less than ideal circumstances.3

It is also worth noting that even patients who progress to foveal detachment generally do well. In the study from St. Thomas’ Hospital, eight of the 10 patients who progressed retained or improved upon their preoperative vision; two patients lost a line of vision.9 The patient from Bascom Palmer whose macula detached recovered 20/40 vision.7

Taken together, these findings suggest that RRD, in most cases, is reasonable to consider as an urgency but not an emergency.

MACULA-OFF RRD

Time to surgery

For patients with RRD who present with an already-detached macula (Figure 2), should surgery still be done urgently? Studies seem to show that sooner is better.2,11-13 One series found that vision was better in patients with one to three days of macular detachment compared with four to six days.2

Figure 2. Macula-off rhegmatogenous retinal detachment in a 52-year-old man with decreased vision for five days prior to presentation.

Another series showed that the final visual outcome is adversely affected after eight days of macular detachment, while visual improvement continues for up to one year if the detachment is repaired within this time frame.12 Additionally, one group found that macula-off detachments repaired within seven to 15 days showed significantly more visual improvement than the delayed group; about half of the former had postoperative visual acuity at 20/30 to 20/60.13 In an anatomic correlate to this, shorter time to surgery has been correlated with a higher mean photoreceptor volume.14

CONCLUSION

In summary, the literature seems to suggest that macula-on RRD is not an emergency condition but is a relatively urgent condition. The surgeon must consider several details when determining the timing for surgical repair as described above. When possible, we prefer to schedule the procedure during business hours in our surgery center, at the first opportunity after seeing the patient. This maximizes the readiness of surgeons and the support teams.

For exceptional cases, such as superior RRDs extending posteriorly and bullous detachments, alternate arrangements like bilateral patching may be helpful in slowing progression of a retinal detachment during the time it takes to get from diagnosis to surgery. Also, bilateral patching may be helpful in slowing progression of a retinal detachment during the time it takes to get from diagnosis to surgery.

Concerning macula-off RRD, our preference is to do the surgery within one week, and sooner if logistics allow. It is reasonable to advise the patient to limit activity and maintain bed rest, or even consider a bilateral eye patch, to prevent further progression. OM

REFERENCES

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