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Peri-operative Investigations
Published in Pradeep Venkatesh, Handbook of Vitreoretinal Surgery, 2023
When the ocular media does not permit detailed evaluation of the retina because of dense cataract, vitreous haemorrhage, amyloidosis, or capsular opacification, it is mandatory to undertake preoperative ultrasonography [USG]. Relatively recent onset [fresh] and dispersed vitreous haemorrhage appears as bright dots on the B scan within the vitreous cavity, with corresponding low to medium reflectivity spikes along the A scan vector. When the haemorrhage is minimal [yet obscuring fundus visualization], one may have to increase the gain setting above tissue sensitivity to identify the haemorrhage on USG [however, beware of increased ‘reflectivity’ caused by increase in background noise]. This may be particularly necessary when trying to detect the presence of dispersed haemorrhage in a vitrectomized eye because blood remains in a liquefied state and is widely dispersed. As the haemorrhage becomes older, dehemoglobinized, and organized, the reflectivity becomes more easily evident. Sometimes vitreous haemorrhage that gets layered inferiorly over a detached hyaloid acquires the features of high reflectivity and can hence be mistaken for retinal detachment. To avoid this error, one must take other attributes of the membrane on USG into consideration before making a final diagnosis. Dot-like vitreous haemorrhage is often associated with membranous echoes, which could be indicative of the hyaloid posterior vitreous detachment [PVD] or detached retina. Dynamic ultrasound examination is very important in making a distinction between these membranes. As a general rule, if a PVD is absent, a retinal tear or rhegmatogenous retinal detachment [RD] is unlikely. If PVD is present, retinal tear [Figure 3.1] or RD should always be ruled out carefully before ascribing the haemorrhage to some other cause. Asteroid hyalosis too manifests as dot-like opacities within the vitreous cavity, but these are larger in size, and there is a distinct clear zone from the retinal surface.
Hypersonic vitrectomy: a novel approach to vitreous removal
Published in Expert Review of Ophthalmology, 2022
Jacob G Light, Hannah Anderson, Sunir Garg
Subsequent series evaluating 23-gauge HV systems had somewhat mixed results. A small case series of 12 patients undergoing HV surgery for vitreous hemorrhage, tractional retinal detachment, secondary IOL placement, macular pucker/hole, and vitreous opacity showed improvement in visual acuity from a mean of 20/125 pre-op to 20/47 one month post-op with no serious intra-operative or post-operative complications [49]. On the contrary, a larger prospective multicenter series of 50 eyes which included additional, and arguably more complex, surgical indications (rhegmatogenous retinal detachments, retained lens material, asteroid hyalosis, post-endophthalmitis, and silicone oil) found a 10% rate (5 cases) of intraoperative complications and ‘technical problems’ in 46% (23 cases) [50]. The most common issue was inadequate vitreous liquefaction and formation of fibrous vitreous strands, resulting in conversion to traditional guillotine cutter vitrectomy in 15 cases (30%). Two cases of scleral thermal burns, requiring scleral suture and resulting in transient post-operative hypotony, were also seen. The authors found that best optimization of the HV performance was at a stroke amplitude of 60 µm and vacuum of 40 mmHg but concluded that eyes with preexisting degenerated soft vitreous were better candidates for HV usage than those with dense, well-formed gel. Despite the technical issues, anatomic success was achieved in 98% of eyes at 3 months with good improvement in visual acuity (mean baseline 20/118 vs. mean final 20/36).
PRPH2-Associated Macular Dystrophy in 4 Family Members with a Novel Mutation
Published in Ophthalmic Genetics, 2022
Hanna Choi, Alan Cloutier, David Lally
The proband’s 90-year-old mother was analyzed. A recent visual acuity of the mother was not obtained, but measurements from 7 years prior were 20/200 in both eyes. The mother has a history of epiretinal membranes in both eyes. Fundus examination showed round, unifocal atrophic lesions in the central macula in conjunction with peripheral reticular degeneration and atrophy of each eye. The left fundus had asteroid hyalosis (Figure 2d). The SD-OCT showed disruption of the macular RPE with parafoveal loss of the outer retina and epiretinal membranes in each eye. The foveal ellipsoid zone (EZ) appeared intact in each eye. FAF demonstrated hypoautofluorescence with junctional hyperautofluorescence. Only the right macula showed a focal absence of autofluorescence within the atrophic lesion (Figure 2c).
Advances in the tools and techniques of vitreoretinal surgery
Published in Expert Review of Ophthalmology, 2020
Ashish Markan, Aman Kumar, Jayesh Vira, Vishali Gupta, Aniruddha Agarwal
David Kasner has been credited to perform first open sky cellulose sponge vitrectomy, though Tsugio Dodo used a technique he termed ‘dia pupillary resection’ for subtotal removal of a vitreous hemorrhage from a patient years before Kasner started performing open sky vitrectomies. In 1969, David Kasner initially used his technique of vitreous removal to deal with cataract surgery complications, and later to perform intentional, subtotal vitreous removal in patients of trauma and patients with asteroid hyalosis [3]. His work led others to more fully advance vitrectomy surgery. Robert Machemer, known as father of modern vitreoretinal surgery, performed his first machine vitrectomy through pars plana route using a battery-powered, hollowed-out drill with a side opening, which allowed the drill bit’s rotation to cut small pieces of vitreous that could then be manually aspirated through the drill. He added an infusion tube attached to the side of the cutting device to allow the eye to stay formed as the vitreous was removed. His vitreous infusion suction cutter (VISC) was 17-gauge (1.42 mm in diameter), multifunctional, and utilized a 2.3 mm scleral incision [1]. After Machemer, O’Malley and Ralph Hein developed the three-port vitrectomy with 20-gauge system [4]. The ports were sutured using absorbable sutures.