LAUSR

S urgery for rhegmatogenous retinal detachment with macular involvement has a high reattachment rate, but visual recovery varies among patients. Several predictive and relatively reliable and quantifiable factors have been identified, including preoperative visual acuity and height of the detachment (Ross et al. 2005).Duration ofmacular detachment is a potential predictor as suggested by results of animal studies, in which progressive changes in all retinal layers continue for weeks (Wickhaml et al. 2018). Based on these results, we would expect a linear correlation between the duration of macular detachment and visual acuity outcome in clinical studies. However, this is not obvious in the current literature. Some studies have shown a better visual acuity in patients treated within 3 days of macular detachment, whereas other studies showed no difference in visual recovery when operatedwithin 7 days aftermacular involvement (van Bussel et al. 2014). In our ongoing prospective series of 56 patients with macula off retinal detachment (non-published data: Ng H et al.: Visual acuity incompletely represents visual function in patients after rhegmatogenous retinal detachment with macular involvement, ARVO 2019, abstract number: 6570-A0269), we also fail to find such correlation. Difficulties in determining the duration of macular detachment in patients may explain why the results of animal models do not clearly match those found in clinical studies. An obvious difference in methodology is that, in animal studies, the moment of macular detachment is known, whereas in the clinical situation, we rely on history taking only. Thus, we are dependent on a patient’s perception and interpretation of complaints in response to the physician’s questions. This difficulty of obtaining information is acknowledged in some studies by reporting the number of patients with a distinct answer (Burton 1982). Only some studies report which questions (such as ‘central vision loss’, ‘significant visual loss’ or ‘onset of macular symptoms’) were asked. From a larger study on delays of presentation of retinal detachment (Eijk et al. 2016), we tried to develop a selection of questions believed to help pinpoint the moment the macula came off. We also addressed whether the patient had covered the other eye when noticing changes and whether they were aware of having a dominant eye. To test these questions for their specificity, we interviewed 35 patients with a macula off detachment and 30 patients with a macula on retinal detachment. In 14 patients (41%) with macula off retinal detachment, a time of macular detachment could not be determined. We found, however, that when patients with a definite macula on retinal detachment were asked the same questions, 15-40% of the responses were as if their macula was actually detached (non-published data, CossackN. et al., DutchOphthalmology Society meeting 2012). Apparently, our questions have a low specificity to identify the duration of macular detachment. Our inability to determine the moment the macula came off may explain why different clinical studies fail to validate each other regarding the correlation of duration of macular detachment and visual outcome. For practical purposes, it may be a better choice not to focus on this conflicting aspect of clinical studies, but act on what is plausible and rational from preclinical studies: to try and reattach the macula sooner rather than later, without rushing to emergency out of hours treatment.