below , we describe some surgical steps that can be imaged using the mioct and its advantages : unlike the hand - held oct , the mioct has the capability to image the anatomical configuration of the scleral entry wound - uniplanar with a 25 g trocar and biplanar with a 23 g trocar . wound apposition after removal of the trocar can also be confirmed [ fig . 1 ] . sclerotomy wound closure with edematous edges ( red circle ) after removal of 23 g trocar the mioct helps in initiating delamination or segmentation of membranes with improved precision , thereby reducing the risk of damage to the underlying tissues . in cases of diffuse and plastered tractional retinal detachment , the most crucial step is in identifying a safe plane to initiate membrane peeling which the mioct aids in [ fig . 2 ] . at the end of surgery , it helps determine if any residual traction exists in the form of secondary or tertiary membranes , as well as in determining the adequacy of membrane peeling [ fig . 3 ] . mioct is particularly useful in cases of vitreous hemorrhage to assess the macular status intra - operatively for the presence of membranes or macular edema since preoperative evaluation may not have been possible . broad based adhesions with bridging retinal tissue assessing the adequacy of membrane peeling the mioct helps the surgeon to assess the strength of vitreomacular adhesions , and this may , therefore , decrease the risk of de - roofing of the foveal cyst and inadvertent creation of a macular hole [ fig . 4 ] . it helps in the complete removal of the epiretinal membrane / internal limiting membrane ( ilm ) and prevents inadvertent grasping of the retina thereby avoiding iatrogenic retinal tears or breaks . vitreomacular traction extent can be assessed intraoperatively in myopic foveoschisis , there are multiple layers of vitreoschisis [ fig . 5 ] requiring vital dye staining to ensure that all the cortical vitreous has been removed . multiple staining processes can be avoided by confirming intraoperatively that no posterior hyaloid has been left behind . furthermore , in myopic eyes , due to a longer axial length and poor contrast of the stain , the mioct can help better assess the ilm . since myopic retinae are thinner , iatrogenic breaks may be prevented by better visualization of the planes intraoperatively . myopic foveoschisis is imaged despite the longer axial length in cases of the macular hole , while initiating the ilm peeling , surgeons are often concerned about inadvertent nerve fiber layer touch or breaks , which may lead to positive scotomas . this can be avoided with the mioct as it provides real - time imaging of the ilm peel . it is possible to do away with staining using vital dyes as the peeled ilm is well visualized as a scrolled membrane [ fig . it is also possible to observe the opposition of edges of the macular hole after peeling the ilm . cystoid macular edema with a lamellar macular hole can be well - demonstrated with the mioct [ fig . 7 ] . peeled internal limiting membrane seen as a scroll providing a visual cue of completion rolled edges of the retinal break helps localization of the lesion during surgery in cases of retinal detachment , mioct can assist during induction of posterior vitreous detachment , detection of any residual subretinal fluid at the posterior pole and completion of fluid air exchange . it can also detect the presence of proliferative vitreoretinopathy changes and rolled edges of retinal breaks [ fig . plana lensectomy , since the anterior segments details are well - delineated on mioct , it is possible to monitor an intact anterior capsule [ fig . cystoid macular edema with a lamellar macular hole monitoring the anterior capsule during pars plana lensectomy the field of intra - operative oct in rop remains largely unexplored . owing to the nature of the disease , it is likely to provide the surgeon the opportunity to assess the depth of the engaging preretinal membranes during lens sparing vitrectomy ( lsv ) . with the mioct , the surgeon may be able to determine the extent of both horizontal and anteroposterior tractional elements , thereby allowing careful dissection or peeling while sparing the retinal elements . this could help in determining the appropriate plane for dissection and improving the chances of anatomical outcome in these cases . in addition , the use of mioct in rop and other vascular retinopathies like familial exudative vitreoretinopathy may help image the flat neovascular fronds that often attend this pathology in its acute phase . especially , if lsv with endo laser is being considered , determining the location and extent of these neovascular fronds would be useful in preventing iatrogenic hemorrhage . some of the drawbacks of this system include : 
 targeting the oct field - of - view to the area of interestvisualization of the instrument and the underlying retina can be affected by the optical properties of surgical instruments which can cause obscuration due to back shadowing [ fig . 10 ] . 
 metallic instruments ( e.g. forceps and needles ) - high reflectivity with total shadowing below the instrumentpolyamide material - moderate reflectivity with subtotal shadowingsilicone instrumentation - moderate reflectivity with minimal shadowing . 

  targeting the oct field - of - view to the area of interest visualization of the instrument and the underlying retina can be affected by the optical properties of surgical instruments which can cause obscuration due to back shadowing [ fig . 10 ] . metallic instruments ( e.g. forceps and needles ) - high reflectivity with total shadowing below the instrumentpolyamide material - moderate reflectivity with subtotal shadowingsilicone instrumentation - moderate reflectivity with minimal shadowing . 
  metallic instruments ( e.g. forceps and needles ) - high reflectivity with total shadowing below the instrument polyamide material - moderate reflectivity with subtotal shadowing silicone instrumentation - moderate reflectivity with minimal shadowing . obscuration of underlying tissue by instrument back shadowing is a limitation with the evolution of the portability of the hand - held oct technology from a dismantled hand - piece to integration into the assistant scope of the operating microscope , the terminology has evolved from intraoperative oct to a microscope mounted oct to an mioct . with the availability of a truly co - axial system that is integrated into the operating microscope in the mioct , it is finally possible to have a true intra - operative surgical assist . there is now potential to transform the oct from a research tool into a surgical assistive device . using this technology , we can achieve a greater understanding of the intraoperative retinal morphological changes by observing real - time instrument tissue interaction . this can help us better understand the variations in postoperative structural and functional results and , therefore , help prognosticate surgical outcomes more objectively . unlike the hand - held oct , the mioct has the capability to image the anatomical configuration of the scleral entry wound - uniplanar with a 25 g trocar and biplanar with a 23 g trocar . wound apposition after removal of the trocar can also be confirmed [ fig . 1 ] . sclerotomy wound closure with edematous edges ( red circle ) after removal of 23 g trocar the mioct helps in initiating delamination or segmentation of membranes with improved precision , thereby reducing the risk of damage to the underlying tissues . in cases of diffuse and plastered tractional retinal detachment , the most crucial step is in identifying a safe plane to initiate membrane peeling which the mioct aids in [ fig . , it helps determine if any residual traction exists in the form of secondary or tertiary membranes , as well as in determining the adequacy of membrane peeling [ fig . 3 ] . mioct is particularly useful in cases of vitreous hemorrhage to assess the macular status intra - operatively for the presence of membranes or macular edema since preoperative evaluation may not have been possible . the mioct helps the surgeon to assess the strength of vitreomacular adhesions , and this may , therefore , decrease the risk of de - roofing of the foveal cyst and inadvertent creation of a macular hole [ fig . it helps in the complete removal of the epiretinal membrane / internal limiting membrane ( ilm ) and prevents inadvertent grasping of the retina thereby avoiding iatrogenic retinal tears or breaks . in myopic foveoschisis , there are multiple layers of vitreoschisis [ fig . 5 ] requiring vital dye staining to ensure that all the cortical vitreous has been removed . multiple staining processes can be avoided by confirming intraoperatively that no posterior hyaloid has been left behind . furthermore , in myopic eyes , due to a longer axial length and poor contrast of the stain , the mioct can help better assess the ilm . since myopic retinae are thinner , iatrogenic breaks may be prevented by better visualization of the planes intraoperatively . in cases of the macular hole , while initiating the ilm peeling , surgeons are often concerned about inadvertent nerve fiber layer touch or breaks , which may lead to positive scotomas . this can be avoided with the mioct as it provides real - time imaging of the ilm peel . it is possible to do away with staining using vital dyes as the peeled ilm is well visualized as a scrolled membrane [ fig . it is also possible to observe the opposition of edges of the macular hole after peeling the ilm . cystoid macular edema with a lamellar macular hole can be well - demonstrated with the mioct [ fig . 7 ] . peeled internal limiting membrane seen as a scroll providing a visual cue of completion rolled edges of the retinal break helps localization of the lesion during surgery in cases of retinal detachment , mioct can assist during induction of posterior vitreous detachment , detection of any residual subretinal fluid at the posterior pole and completion of fluid air exchange . it can also detect the presence of proliferative vitreoretinopathy changes and rolled edges of retinal breaks [ fig . plana lensectomy , since the anterior segments details are well - delineated on mioct , it is possible to monitor an intact anterior capsule [ fig . 9 ] . cystoid macular edema with a lamellar macular hole monitoring the anterior capsule during pars plana lensectomy owing to the nature of the disease , it is likely to provide the surgeon the opportunity to assess the depth of the engaging preretinal membranes during lens sparing vitrectomy ( lsv ) . with the mioct , the surgeon may be able to determine the extent of both horizontal and anteroposterior tractional elements , thereby allowing careful dissection or peeling while sparing the retinal elements . this could help in determining the appropriate plane for dissection and improving the chances of anatomical outcome in these cases . in addition , the use of mioct in rop and other vascular retinopathies like familial exudative vitreoretinopathy may help image the flat neovascular fronds that often attend this pathology in its acute phase . especially , if lsv with endo laser is being considered , determining the location and extent of these neovascular fronds would be useful in preventing iatrogenic hemorrhage . some of the drawbacks of this system include : 
 targeting the oct field - of - view to the area of interestvisualization of the instrument and the underlying retina can be affected by the optical properties of surgical instruments which can cause obscuration due to back shadowing [ fig . - high reflectivity with total shadowing below the instrumentpolyamide material - moderate reflectivity with subtotal shadowingsilicone instrumentation - moderate reflectivity with minimal shadowing . targeting the oct field - of - view to the area of interest visualization of the instrument and the underlying retina can be affected by the optical properties of surgical instruments which can cause obscuration due to back shadowing [ fig . - high reflectivity with total shadowing below the instrumentpolyamide material - moderate reflectivity with subtotal shadowingsilicone instrumentation - moderate reflectivity with minimal shadowing . metallic instruments ( e.g. forceps and needles ) - high reflectivity with total shadowing below the instrument polyamide material - moderate reflectivity with subtotal shadowing silicone instrumentation - moderate reflectivity with minimal shadowing . obscuration of underlying tissue by instrument back shadowing is a limitation with the evolution of the portability of the hand - held oct technology from a dismantled hand - piece to integration into the assistant scope of the operating microscope , the terminology has evolved from intraoperative oct to a microscope mounted oct to an mioct . with the availability of a truly co - axial system that is integrated into the operating microscope in the mioct , it is finally possible to have a true intra - operative surgical assist . there is now potential to transform the oct from a research tool into a surgical assistive device . using this technology , we can achieve a greater understanding of the intraoperative retinal morphological changes by observing real - time instrument tissue interaction . this can help us better understand the variations in postoperative structural and functional results and , therefore , help prognosticate surgical outcomes more objectively .
optical coherence tomography ( oct ) has revolutionized imaging of ocular structures and various disease conditions . 
 though it has been used in the clinic for some decades , the oct has only recently found its way into the operating theater . 
 early attempts at intraoperative oct , hand - held and microscope mounted , have already improved our understanding of the surgical pathology and the role it might play in surgical decision - making . 
 the microscope - integrated oct now allows seamless , high - resolution , real - time imaging of surgical maneuvers from the incision to wound closure . 
 visualization of instruments and intraoperative tissue manipulation are possible with this in vivo modality and , therefore , help improve the outcome of surgery . in this article 
 , we describe the advantages it offers during various vitreoretinal procedures .