RAP study, report 1: novel subtype of macular neovascularisation type III, cilioretinal MNV3

Abstract

PurposeTo report on patients with macular neovascularisation type III (MNV3) arising from cilioretinal arteries (CRAs) (cilioretinal macular neovascularisation type III (cMNV3)).MethodsWe reviewed baseline examinations of patients with neovascular age-related macular degeneration using multimodal imaging. We determined the type and distribution of MNV lesions in each cMNV3 case, the range of distances from the fovea, existence of exudative maculopathy, intraretinal haemorrhage and other morphological characteristics. 50 consecutive eyes with usual MNV3 without CRA were included as a control group.Results102 eyes of 102 patients were identified with MNV3 lesions. Among these, we found 12 eyes (12%) with cMNV3, 84 eyes (82%) with usual MNV3 without CRA and 6 eyes (6%) with usual MNV3 with CRA. Ten cases of cMNV3 had one lesion, and two cases had two lesions. The lesions were distributed equally between the superior and inferior halves of the macula, whereas in the nasal and temporal halves, there were 8 (57%) and 6 (43%) lesions, respectively. All cMNV3 lesions were located between 500 and 1500 µm from the central fovea except one, which was located between 1500 and 3000 µm. None of the lesions had macular neovascularisation type I (MNV1) or macular neovascularisation type II (MNV2) elsewhere in both groups. Exudative maculopathy and intraretinal haemorrhage were found in seven (88%) and five (63%) of the eight pure cMNV3 cases, respectively.ConclusioncMNV3 can be solitary or multiple, isolated or accompanied with usual MNV3 lesions, but not with concurrent MNV1 or MNV2. It is frequently associated with extensive exudative maculopathy, intraretinal haemorrhage and subretinal fluid.

The RAP study, report 4: morphological and topographical characteristics of multifocal macular neovascularization type 3

“…Its contribution to the blood supply of multifocal lesions was found in quarter of eyes which is within the normal range of existence of CRA in healthy eyes [29,30]. We noticed a similar finding in our evaluation of 12 MNV3 eyes with CRA feeding vessels [6]. In other words, this supports our results in the first report that CRA does not play a protective factor against development of MNV as it was previously proposed [31].…”

“…Most eyes were associated with hard exudate and intraretinal hemorrhage. We noticed similarly high percentages of exudative changes on both solitary and cilioretinal MNV3 in a previous work [ 6 ]. A possible explanation for this morphology could be the higher permeability of the retinal component of the neovascular complex in MNV3 compared with the choroidal NV in MNV1 or 2 [ 13 ], and also the intraretinal location of the lesions, where the extravasation from the angiogenic network is not blocked by the outer blood-retinal barrier as it is the case with the choroidal NV.…”

“…Patients with MNV3 are usually older than those with other types [ 2 , 10 ]. Therefore, it was surprising, as in our previous two reports on solitary and cilioretinal MNV3 [ 3 , 6 ], not to find concurrent MNV1 or 2 lesions elsewhere in the macula, given that all three types share many risk factors and have similar morphological characteristics in early and intermediate AMD. Furthermore, in MNV3, which was first described more than 28 years ago [ 18 ], there is still no report to the best of our knowledge about a concurrent development of MNV1 or 2 lesion with MNV3.…”

“…The angiogenic network usually originates from the retinal vessels at first and extends deeply through the retinal pigment epithelium to the subretinal space and anastomose with the underlying choroidal neovessels eventually [1,2]. Many crucial differences from the other two MNV types have recently been raised, for example, its tendency to distribute in the temporal half of the macula, the contribution of the cilioretinal artery (CRA), and the possible role of disturbance of choroidal blood perfusion and rod damage on its pathogenesis process [3][4][5][6]. Moreover, this type affects patients older than those with type 1 or 2 and can be bilateral in up to all cases [7][8][9].…”

“…There is increasing literature about MNV3 including its development and morphological and pathological characteristics in different imaging methods or its response to treatment but these were done on solitary MNV3 [ 1 , 10 , 11 ]. Nonetheless, we found 3 cases of bifocal lesions in our first report on the cilioretinal variant of MNV3 [ 6 ]. This outcome led us to initiate an evaluation of multifocal MNV3 (mMNV3) as a variant accounting for 12% of MNV3 cases[ 12 ].…”