World-renowned retinal surgeons provide maneuvers and tricks for better surgical outcomes in challenging cases

Surgical Retina

Techniques and Maneuvers for Better Outcomes

by Tan Sher Lynn

Various novel surgical techniques and maneuvers were discussed in a live stream during the American Society of Retina Specialists 38 th Annual Scientific Meeting (ASRS 2020) on July 24, 2020. Here are some of the highlights…

Sutureless intrascleral fixation

The two-part Surgical Techniques and Maneuvers Symposium started with Dr. Ashkan Abbey from the Texas Retina Associates (USA) , who presented the clinical outcomes of 488 eyes which received sutureless intrascleral (SIS) fixation of intraocular lenses (IOL) as well as the comparative effectiveness of haptic flanging in the series.

“Postoperative IOL dislocation in eyes undergoing SIS fixation is most likely to occur after repositioning of a previously dislocated IOL,” he shared. The risk of postoperative IOL dislocation, emphasized Dr. Abbey, may be reduced by having a low threshold for exchanging a warped or damaged 3-piece IOL. “Flanging of the haptic tips significantly reduces the risk of IOL dislocation. Intraoperative peripheral iridotomies significantly reduce the risk of postoperative reverse pupillary block,” he added.

Using microsurgical vacuum pick

Then, Dr. Carl Awh from Tennessee Retina (USA) described the use of the microsurgical vacuum pick (MVP) for membrane peeling without forceps during vitreoretinal surgery. The MVP is a new device that can perform all membrane peeling steps, including creating a membrane edge, securing the membrane, and peeling the membrane from the retina. The most novel feature of the MVP is the micropicks, which is used to create an edge or flap in the ILM or ERM, with minimal risk of damage to the underlying retina. “The MVP seems more stable and less fatiguing – there’s no need to activate the forceps. It reduces or eliminates instrument exchange. The teasing action used to peel membranes may transmit less stress to macula than peeling with forceps. However, there are occasions when I still prefer the forceps, such as in cases of extremely thick or rigid membranes,” said Dr. Awh.

Dealing with large macular holes

Despite a high success rate for macular hole repair (>90%), there are challenging cases that involves large holes (>400 microns), chronic holes (>6 months), macular holes in high myopia and recurrent holes. Dr. Jessica Lee from New York Eye and Ear Infirmary of Mount Sinai (USA) talked about the use of human amniotic graft in the repair of persistent large MH. The study involves 10 patients who had persistently open large macular holes from 3/2019 to 5/2020. All patients underwent pars

plana vitrectomy (PPV) with a circular patch of subretinal amniotic membrane.

“Pre-op, the mean best corrected visual acuity (BCVA) was 1.6LogMar or 20/800, while the mean postoperative BCVA was 1.26LogMar or 20/320 (6 months post-op). In all 10 cases, the macular hole appeared closed at the 1-week post-operative visit. All holes remained closed at the last follow-up with a BCVA of 20/400 and no adverse events occurred,” she reported.

“An important thing to note during amniotic membrane transplantation is to make sure that the sticky side of the membrane is the side that you place onto the macular hole, which will prevent it from dislodging,” explained Dr. Lee.

In the second part of the symposium, Dr. Shree Kurup from the University Hospitals Cleveland (Ohio, USA) presented an interesting post hoc analysis of the new clinical suprachoroidal injection experience for non-infectious uveitis with the SCS Microinjector (Clearside Biomedical, GA, USA).

Seventy-four per cent (74%) of 133 total baseline injections were completed with the 900µm needle; the remaining with the 1100µm needle. Univariate analysis revealed no relationship between needle length and gender, lens status, uveitis location, disease course or onset. Disease duration was statistically correlated with needle length: 91% of injections were completed with the 900µm needle for Limited (≤ 3 months) and 70% for Persistent (> 3 months).

“Age was moderately inversely correlated with needle length. Injection quadrant was statistically related: 82% of injections administered temporally were completed with the 900 µm needle compared to 45% of injections administered nasally. In the user experience survey, over 80% of the physicians responded that SC injections presented no new challenges compared to other types of injections,” said. Dr. Kurup.

The link to Alzheimer’s

Meanwhile, Dr. Manju Subramanian from the Boston University School of Medicine (USA) talked about her investigation regarding the presence of neurofilament-light chain (NfL) in the vitreous humor and its associations with levels of Alzheimer’s Disease (AD) biomarkers such as amyloid beta (Aß) and total and phosphorylated Tau (t-Tau and p-Tau) proteins and inflammatory proteins in eyes. “NfL is identified in all 77 samples of undiluted vitreous and 78% of our sample have levels of 20 pg/mL or more,” reported Dr. Subramanian.

NfL level was significantly associated with increased vitreous levels of Aß 40 , Aß 42 and t-Tau, specific inflammatory/ vascular protein with known systemic AD association, she noted. “NfL was not correlated with eye disease, APOE genotypes, or cognition. Cumulatively, results indicate that NfL in the vitreous appears to be a marker for systemic neurodegeneration,” she said.

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