New optical coherence tomography grading system for macula-off rhegmatogenous retinal detachment: how off is off?

Abstract

Background/AimsThe classification of retinal detachment is currently still based on many objective criteria such as duration of symptoms and funduscopic macular status, which leaves some important questions unanswered. The most important factor is the macular status, which is determined using direct or indirect ophthalmoscopy. Optical coherence tomography (OCT) has become a standard tool in clinical practice and enables detecting the exact extent of subretinal fluid in macula-off/on retinal detachment. We introduce a new and simple OCT-based grading system for macular detachment to provide a basis for further investigations to determine the optimal timing for surgery.MethodsWe retrospectively included 155 patients who were treated for retinal detachment. We defined the extent of the macular detachment in six stages based on the Early Treatment Diabetic Retinopathy Study (ETDRS) grid of the OCT scan.The outermost ring of the ETDRS grid was defined as zone 1, the middle ring as zone 2 and the inner ring as zone 3. Only zone 3 differed in the retinal detachment height grades (grade a <250 µm vs grade b >250 µm). Retinal detachment heights that could not be measured were considered grade 4 (ungradable) detachments.ResultsForty-seven patients had no macular involvement (grade 0). Regarding macular detachment, 14 patients had grade 1, 20 had grade 2, 9 had grade 3a, 29 had grade 3b and 36 had grade 4.ConclusionThe newly developed OCT grading system for macular involvement following retinal detachment is a crucial tool to objectively classify a retinal detachment in order to be able to make better statements in the future, like for defining the optimal time for surgical intervention. A secondary benefit of this grading system would be that it improves predicting postoperative visual acuity.

How should we report the foveal status in eyes with “macula-off” retinal detachment?

“… Reference No. Author (et al) Assessment of the macular status with preoperative oct a Specification of the extent of macular detachment a Method to assess the extent of macular detachment Diagnostic modality used to assess the extent of detachment Specific nomenclature to distinguish extent of detachment [ 19 ] Angermann R yes yes submacular fluid volume oct – [ 20 ] Lu B yes no – – – [ 21 ] Chua J no no – – – [ 22 ] Soares RR no yes >50% detachment not specified – [ 23 ] Lee CS no yes quadrants not specified – [ 24 ] Boden KT yes yes ETDRS grid, height of detachment oct Grade 1–4 (Zone 1–3) [ 25 ] Guan I yes yes height of detachment oct – [ 26 ] Ersoz M yes yes not specified – – [ 4 ] Klaas JE yes yes ETDRS grid, height of detachment oct MIRD, CIRD (Grade 1–5) [ 27 ] Christou E no yes …”

“…While most retina specialists may have accepted the term “macula-off” as a sufficient means to describe a detached foveal status, a review of 40 recent publications focusing on “macula-off” retinal detachment (search term “macula-off” or “fovea-off” on pubmed.gov, date April 28 th , 2021, Table 1 ) highlights that the term “macula-off” may include a variety of morphological states which, - depending on the degree of detail, – may be based on different diagnostic methodologies, ranging from fundoscopy-based approaches (e.g. “clock hours”, “quadrants”) to grid-based strategies using preoperative OCT, albeit comparatively rarely [ 1 , 2 , 24 , 52 , 61 , 62 ]. The inconsistency in assessing and reporting the macular status, as is evident in the up-to-date scientific literature is even more surprising with the continuous technical improvements of OCT devices over the past two decades, especially in high detachments [ 18 ].…”

“…Boden et al have suggested combining the height of foveal detachment with the extent of detachment in a further ETDRS-grid-based grading scheme in 108 eyes with macula involving retinal detachment (Fig. 4 ) [ 24 ]. But what if we cannot assess the height of detachment due to high detachment of the macula by OCT?…”

“…Ultimately, however, precise imaging may be more important in eyes with a lower amount of subretinal fluid and a lower extent of detachment that could benefit most from earlier surgery. This could prevent further structural damage, visualised through morphological changes in the preoperative OCT, such as the formation of cystoid cavities or early outer retinal atrophy [ 2 , 4 , 24 , 66 ].

Fig.

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“… Visualisation of a grid-based grading system for eyes with macula involving retinal detachment using the 1.0 mm (red), 3.0 mm (pink) and 6.0 mm (yellow) diameter of the ETDRS grid as proposed by Boden et al [ 24 ]. Grade 3 is further subdivided according to the height of foveal detachment in the corresponding OCT scan (cutoff = 250 µm).…”