With complications and controversies surrounding internal limiting membrane (ILM) peeling, is it really necessary to do so? This and other controversies and innovations in surgical retina were among the highlights and issues tackled on Day 1 of the 15th Asia-Pacific Vitreo-retina Society (APVRS) Congress, as retinal surgeons presented the latest ideas and progress in vitreous surgery and the pathology of vitreoretinal diseases.
To Peel or Not to Peel
ILM peeling has been proposed as a method used to prevent epiretinal membrane (ERM) formation in eyes that have undergone vitrectomy for rhegmatogenous retinal detachment (RRD). However, ILM peeling may cause retinal damage during surgery and delay visual recovery. It is also difficult to peel the ILM in eyes with macula-off RRD complicated by proliferative vitreoretinopathy (PVR).
Hence, “is ILM peeling necessary to do so?” — asked Dr. Shumpei Obata from Japan.
Using prospective data from the Japan-Retinal Detachment Registry, Dr. Obata and his colleagues compared the anatomical outcomes and visual acuity (VA) changes between eyes with ILM peeling and eyes without ILM peeling on subjects who had macula-off RRD complicated by PVR. They found that removal of ERM was unnecessary in all eyes with ILM peeling, while it was necessary for 3% of eyes without ILM peeling. Meanwhile, preoperative VA and younger patient age were significantly associated with poor postoperative VA at 6 months. However, ILM was not associated with poor VA. They also looked at previous studies that showed controversies regarding the effect of ILM peeling on the anatomical outcome.
“ILM peeling does not have a clear beneficial effect in anatomical and functional outcomes, and it might be unnecessary for macula-off RRD complicated by PVR,” shared Dr. Obata.
Scleral Buckle vs. Pars Plana Vitrectomy
There are many ways to fix retinal detachment, such as scleral buckle, pars plana vitrectomy, and pneumatic retinopexy. When it comes to choosing the right procedure for the patient, Dr. Wong Jun Shyan from Malaysia said that the safety, efficacy, simplicity, and cost-effectiveness of the procedure should be taken into consideration.
“Scleral buckle can be done with minimal high-tech instruments, is particularly useful in simple retinal detachment in young patients with no (or incomplete) posterior vitreous detachment (PVD), does not require posturing, is without air travel restrictions, and is especially good in inferior detachment with PVR<grade B. But it is technically demanding, and is less frequently taught in training programs nowadays,” Dr. Wong explained.
On the other hand, vitrectomy allows the elimination of vitreous traction, removal of media opacities, better visualization of breaks, and controlled internal drainage of subretinal fluid. There are also no worries over problems related to external drainage, hemorrhage, retinal incarceration, and others. There are also minimal risk of diplopia from buckle element, minimal distortion of globe and astigmatism, as well as less morbidity compared to scleral buckle.
“Both techniques are important in retinal detachment (RD) repair, and the decision to choose which procedure [to choose] is influenced by patient and surgeon factors,” continued Dr. Wong.
“Final reattachment outcomes are similar in both procedures, while single operation success tends to be slightly higher in PPV. The visual quality of the procedures is not fully addressed in the literature. Nevertheless, vitrectomy is now the mainstay of RD repair in 2022,” he concluded.
Endophthalmitis Trends and Complications
Acute endophthalmitis can cause severe devastating complications. “We used to see endophthalmitis complications in post-cataract cases, but following the exponential rise of intravitreal injections (IVI), we are seeing more and more of them nowadays,” said Dr. Andrew Chang from Australia, noting that the risk of endophthalmitis is 0.008% to 0.092% following IVI and 0.03% to 0.7% following cataract surgery.
According to him, the condition can be due to patient-related factors (such as the patient’s own flora [67-82% bacterial isolates on conjunctiva]), procedure-related factors (unplanned anterior vitrectomy, which increases the risk ten times), or surgeon-related factors (poor sterile technique).
Wanting to explore the difference in outcomes between endophthalmitis following cataract surgery and IVI, Dr. Chang and his colleagues examined 101 eyes in 101 patients with acute endophthalmitis (53 post-IVI, 48 post-cataract surgery) at the Sydney Hospital, and found that post-IVI endophthalmitis had poor outcomes, with increased Streptococcus infection (24.53% vs 6.25%). They also examined the changing spectrum of endophthalmitis in the Sydney Hospital and found that there were less Streptococcus cases (although they were still common), probably due to the use of masks and reduced talking.
Meanwhile, through the Sydney Eye Hospital Early Vitrectomy Study, they found that culture-negative endophthalmitis and post-cataract surgery endophthalmitis were associated with better visual outcomes. In terms of technology, Dr. Chang noted that micro-incisional vitrectomy is effective in improving vision in acute infective endophthalmitis. “With changes in technology and patient presentation, we should review the Endophthalmitis Vitrectomy Study (EVS),” he said.
Lutein Supplement for RD
While surgery for RD is effective in reattaching the retina, it may not restore vision. Merely less than one-third of macula-off RD could achieve good vision (6/12 or better) after surgery.
“Since vision loss related to macula-off RD is primarily due to apoptosis of retinal photoreceptors, neuroprotective therapy may prevent apoptosis and thus improve visual outcome,” noted Dr. Danny Cheung from Singapore.
Lutein is a well-known neuroprotective agent for RD due to its blue-light-filtering and anti-inflammatory properties. Having proven that lutein reduces photoreceptor apoptosis in rats with RD, Dr. Cheung and colleagues decided to prove it in human subjects. They carried out the Lutein as a Novel Neuroprotective Adjunctive Therapy to Improve Visual Outcome of Retinal Detachment (LUNAR) Study, which is a prospective, randomized, double-masked, placebo-controlled clinical trial.
The study drug contained 20 mg lutein, 1 mg zeaxanthin, and inactive ingredients; while the placebo contained inactive ingredients only. The treatment group took lutein upon enrolment, and RD surgery was performed within one week. Only patients with primary macula-off RD are included. Results show that on average, the lutein group had better VA than the placebo group (by about 1.5-line or 10 ETDRS letters) at 6-week (23.3% vs 10.3%) and 12-week (18.6% vs 12.8%) visits. The lutein group also consistently showed high macular sensitivity across a 12-month period.
Dr. Cheung shared that oral lutein supplement may improve visual outcome after surgery for primary macula-off retinal detachment.
“Beneficial effects are most prominent during the early to mid-phase of postoperative recovery, suggesting that lutein may promote faster recovery of visual function. However, a larger study may be warranted to verify our results, and to determine if any specific subgroup or type of patients would benefit the most from lutein supplement after surgery,” he concluded.
Editor’s Note: A version of this article was first published in Issue 2 of the APVRS Show Daily – the official congress news of APVRS 2022. APVRS 2022 was held in Taipei, Taiwan, on November 18-20. Reporting for this story took place during the congress.