25-gauge Microincision Vitrectomy Research Articles

Comparison of 27-gauge beveled-tip and 25-gauge flat-tip microincision vitrectomy surgery in the treatment of proliferative diabetic retinopathy: a randomized controlled trial

PurposeTo compare the effectiveness and safety of a 27-gauge (27G) beveled-tip microincision vitrectomy surgery (MIVS) with a 25-gauge (25G) flat-tip MIVS for the treatment of proliferative diabetic retinopathy (PDR).MethodsA prospective, single-masked, randomized, controlled clinical trial included 52 eyes (52 patients) with PDR requiring proliferative membrane removal. They were randomly assigned in a 1:1 ratio to undergo the 27G beveled-tip and or 25G flat-tip MIVS (the 27G group and the 25G group, respectively). During surgery, the productivity of cutting the membrane, the number of vitrectomy probe (VP) exchanges to microforceps, total operation time, vitrectomy time and intraoperative complications were measured. Best-corrected visual acuity (BCVA), intraocular pressure (IOP) and postoperative complications were also assessed to month 6.ResultsForty-seven eyes (47 patients) completed the follow-up, including 25 in the 27G group and 22 in the 25G group. During surgery in the 27G group, cutting the membrane was more efficient (P = 0.001), and the number of VP exchanges to microforceps was lower (P = 0.026). The occurrences of intraoperative hemorrhages and electrocoagulation also decreased significantly (P = 0.004 and P = 0.022). There were no statistical differences in the total operation time or vitrectomy time between the two groups (P = 0.275 and P = 0.372), but the former was slightly lower in the 27G group. Additionally, the 27G group required fewer wound sutures (P = 0.044). All the follow-up results revealed no significant difference between the two groups.ConclusionsCompared with the 25G flat-tip MIVS, the 27G beveled-tip MIVS could be more efficient in removing the proliferative membrane while reducing the occurrence of intraoperative hemorrhages and electrocoagulation using appropriate surgical techniques and instrument parameters. Its vitreous removal performance was not inferior to that of the 25G MIVS and might offer potential advantages in total operation time. In terms of patient outcomes, advanced MIVS demonstrates equal effectiveness and safety to 25G flat-tip MIVS.Trial registrationThe clinical trial has been registered at Clinicaltrials.gov (NCT0544694) on 07/07/2022. And all patients in the article were enrolled after registration.

Modified-dropless protocol (nil intraocular) for micro-incision vitrectomy surgery (MIVS): a retrospective pilot study

BackgroundPerioperative infection and inflammation prophylaxis after ocular surgery has evolved over the years along with improvements in surgical equipment and a growing interest in alternatives to the standard topical eye drops. The purpose of this study is to evaluate the outcomes of a novel, modified-dropless protocol for 23-gauge (23-G), 25-gauge (25-G) and 27-gauge (27-G) micro-incision vitrectomy surgery (MIVS) that omits any intraocular injections of antibiotics or steroids.MethodsThis Institutional Review Board-approved, single-surgeon retrospective study reviewed MIVS post-surgical outcomes in patients who received a modified-dropless protocol from February 2020 to March 2021. A total of 158 charts were reviewed, of which 150 eyes met the eligibility criteria. After each case, patients were administered a 0.5 cc subconjunctival injection of a 1:1 Cefazolin (50 mg/cc):Dexamethasone (10 mg/cc) in the inferior fornix and 0.5 cc of posterior Sub-Tenon’s Kenalog (STK). No intravitreal injections were administered, and no pre- or postoperative antibiotic or steroid eye drops were prescribed. For patients allergic to penicillin, separate subconjunctival injections of 0.25 cc each of Vancomycin (10 mg/cc) and Dexamethasone (10 mg/cc) were administered. The primary safety parameter was postoperative cases of endophthalmitis. Secondary endpoints consisted of Best-Corrected Distance Visual Acuity (BCVA), intraocular pressure (IOP), and postoperative complications (retinal detachments, inflammation, need for additional surgery) within three months of surgery. Statistical analysis was performed using chi-square (χ²) tests for categorical values, and a Student’s t-test to compare continuous outcomes.ResultsThe majority of surgeries (96%) were performed with the 27G MIVS platform. There were no cases of postoperative endophthalmitis. Mean logMAR BCVA improved from 0.71 (± 0.67) to 0.61 (± 0.60) post-operatively (p = 0.02). Excluding patients who had silicone oil tamponade, postoperative BCVA improved from 0.67 (± 0.66) to 0.54 (± 0.55) (p = 0.003). Mean IOP increased from 14.6 (± 3.8) to 15.3 (± 4.1) (p = 0.05). Ten patients required further medication therapy for an increase in IOP, one had inflammatory signs, and 14 required a second surgical intervention mostly due to recurrences of initial surgical indication.ConclusionA modified-dropless postoperative protocol involving subconjunctival and posterior sub-Tenon’s injections only may be a safe and convenient alternative to topical eye drops for patients undergoing MIVS, but additional and larger studies are needed.

27-gauge microincision vitrectomy surgery compared with 25-gauge microincision vitrectomy surgery on wound closure and need for wound suture and other postoperative parameters in the treatment of vitreoretinal disease: A meta-analysis.

We performed a meta-analysis to evaluate the effect of 27-gauge microincision vitrectomy surgery compared with 25-gauge microincision vitrectomy surgery on wound closure and the need for wound suture and other postoperative parameters in the treatment of vitreoretinal disease. A systematic literature search up to June 2022 was performed and 1264 subjects with the vitreoretinal disease at the baseline of the studies; 562 of them were using the 27-gauge microincision vitrectomy surgery, and 722 were using 25-gauge microincision vitrectomy surgery. Odds ratio (OR), and mean difference (MD) with 95% confidence intervals (CIs) were calculated to assess the effect of 27-gauge microincision vitrectomy surgery compared with 25-gauge microincision vitrectomy surgery on wound closure and the need for wound suture and other postoperative parameters in the treatment of vitreoretinal disease using the dichotomous, and contentious methods with a random or fixed-effect model. The 27-gauge microincision vitrectomy surgery subjects had a significantly lower intraoperative and postoperative wound complication (OR, 6.66; 95% CI, 0.46-0.95, P=.02), and wound suture number (OR, 0.38; 95% CI, 0.20-0.71, P=.002), and best corrected visual acuity (MD, -0.03; 95% CI, -0.05 to -0.001, P=.02) compared with 25-gauge microincision vitrectomy surgery in subjects with vitreoretinal disease. However, 27-gauge microincision vitrectomy surgery subjects had no significant difference in the wound closure time (MD, -8.45; 95% CI, -23.44 to 6.55, P=.27), operation time (MD, 0.85; 95% CI, -1.17 to 2.86, P=.41), intraocular pressure at postoperative day 1 (MD, 0.42; 95% CI, -1.45-2.28, P=.66), primary anatomical success rate (OR, 0.83; 95% CI, 0.42-1.63, P=.58), and central macular thickness (MD, 1.81; 95% CI, -21.76 to 25.37, P=.88) compared to 25-gauge microincision vitrectomy surgery in subjects with vitreoretinal disease. The 27-gauge microincision vitrectomy surgery subjects had a significantly lower intraoperative and postoperative wound complication, wound suture number, and best corrected visual acuity, and no significant difference in the wound closure time, operation time, intraocular pressure at postoperative day 1, primary anatomical success rate, and central macular thickness compared to 25-gauge microincision vitrectomy surgery in subjects with vitreoretinal disease. The analysis of outcomes should be with caution because of the low sample size of 12 out of 15 studies in the meta-analysis and a low number of studies in certain comparisons.

Novel Postoperative Dropless Protocol for Micro-Incision Vitrectomy Surgery.

To evaluate the outcomes of a novel postoperative dropless protocol for 25-gauge and 27-gauge micro-incision vitrectomy surgery (MIVS). The institutional review board approved a single-center, retrospective study. A total of 493 surgeries were identified, and 451 cases from 369 patients met eligibility criteria. Instead of pre- or postoperative drops, patients were given a novel postoperative dropless protocol consisting of subconjunctival injections of a 1:1 cefazolin:dexamethasone mix at each sclerotomy and intravitreally, and injection of posterior sub-Tenon's Kenalog. Primary outcome measure was cases of postoperative endophthalmitis. There was one presumed case of endophthalmitis. Anterior chamber paracentesis sample was negative for culture and Gram stain. For all patients, mean logMAR best-corrected visual acuity improved from 0.65 (±0.69) to 0.57 (±0.61) postoperatively (P = 0.004). Mean intraocular pressure increased from 14.5 (±4.3) to 15.5 (±4.8) postoperatively (P < 0.001). Mean follow-up was 96 days. This novel postoperative dropless protocol could potentially be a convenient alternative to topical eye drops for patients undergoing MIVS, but further study is required to establish its safety. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:587-592.].

Outcomes of Primary 27-Gauge Vitrectomy for 73 Consecutive Cases With Uveitis-Associated Vitreoretinal Disorders.

Background: Since the advent of 27-gauge microincision vitrectomy system a decade ago, evidence regarding the feasibility, safety, and effectiveness of 27-gauge pars plana vitrectomy (PPV) has increased.Aim: To assess the effectiveness and safety profile of 27-gauge PPV for various vitreoretinal conditions associated with uveitis.Methods: We retrospectively investigated 73 consecutive cases that underwent primary 27-gauge PPV for uveitis-related ocular disorders between October 2014 and April 2021. The primary outcome measures were mean change in logMAR best-corrected decimal visual acuity (BCVA) pre-operatively to 3 months post-operatively, the proportion of BCVA improvement category defined as the degree of logMAR BCVA difference (“improved” [≤−0.3], “unchanged” [−0.3 to 0.3], and “worsened” [≥0.3]) pre-operatively to 3 months post-operatively, the mean change in intraocular inflammation scores pre-operatively to 3 months post-operatively; and intraoperative and post-operative complications.Results: The mean logMAR BCVA significantly improved from 0.69 pre-operatively to 0.42 at 3 months post-operatively (P = 0.017). The percentages of eyes with “improved,” “unchanged,” and “worsened” BCVA at 3 months post-operatively were 37, 50, and 13%, respectively. The mean anterior chamber cell score was 0.6 pre-operatively and 0.2 at 3 months post-operatively (P = 0.001), the mean anterior chamber flare score was 0.4 pre-operatively and 0.1 at 3 months post-operatively (P = 0.004), and the mean vitreous haze score was 1.9 pre-operatively and 0.1 at 3 months post-operatively (P < 0.001). Surgery-related complications occurred in 35 (48%) eyes, 68% of which were related to intraocular pressure and transient.Conclusions: Given its risk–benefit profile, 27-gauge PPV is a promising option for the treatment of vitreoretinal disorders in uveitis.

A 27 - Gauge Microincision Vitrectomy Surgery for Posterior Segment Diseases in a Tertiary Centre, Nepal

Introduction: Transconjunctival micro incision vitrectomy surgery (MIVS) with 23 or 25 gauge instrumentation is more advantageous than traditional 20 gauge surgery. We intended to evaluate the visual outcome, complications and indication of various vitreoretinal diseases using 27 Gauge vitrectomy systems. &#x0D; Methods: This study was a prospective, interventional, non-comparative study conducted in Nepal Eye Hospital from June 2017 to July 2018. Fifty-two patients with various vitreoretinal diseases were recruited. The main outcome measures included corrected distance visual acuity (CDVA) preoperative and postoperative, intraocular pressure (IOP) preoperative and postoperative, indication for vitreoretinal surgery, intraoperative complications, and postoperative complications.&#x0D; Results: Fifty two eyes of 52 patients (26 men and 26 women; mean age, 59 years) underwent 27-gauge pars planavitrectomy. Surgical indications included epiretinal membrane (n = 11), full-thickness macular hole (n = 11), rhegmatogenous retinal detachment [n = 14 (12 vitrectomy only and two vitrectomy with scleral buckle)], vitreous haemorrhage (n = 3), vitreous opacities (n = 3), silicon oil removal (n = 3), proliferative diabetic retinopathy [n = 6 (5 vitreous haemorrhage and one tractional retinal detachment)], posterior IOL dislocation (n = 1). Postoperative complications included transient ocular hypertension in eight eyes (15.39%), transient hypotony in five eyes (9.62%) and vitreous haemorrhage in five eyes (9.62%). No cases of postoperative endophthalmitis, sclerotomy - related tears, or choroidal detachments were encountered in the follow-up period. Mean corrected distance visual acuity improved from 20 / 796 (logarithm of the minimum angle of resolution, 1.60 ± 0.64) preoperatively to 20 / 49 (logarithm of the minimum angle of resolution, 0.42 ± 0.26) postoperatively (p = 0.000,) at final follow up.&#x0D; Conclusions: 27-gauge micro-incision vitrectomy surgery was found to be a safe and effective suture-less surgery with favourable outcomes, in terms of vision.

Role of ICAM-1 in impaired retinal circulation in rhegmatogenous retinal detachment

Many studies have demonstrated that rhegmatogenous retinal detachment (RRD) leads to impaired retinal circulation. However, the involvement of inflammation in the RRD-induced worsening of retinal circulation was obscure. This retrospective observational study included 150 patients with primary RRD (macula-on, n = 63; macula-off, n = 87) who underwent 25-gauge microincision vitrectomy surgery (25G MIVS). Total retinal blood flow was represented by the mean blur rate (MBR) of the optic nerve head vessel, measured by laser speckle flowgraphy preoperatively and until 6 months postoperatively. Aqueous humor samples were obtained during surgery to determine cytokine concentrations by enzyme-linked immunosorbent assay. At 3 and 6 months postoperatively, there were no significant differences between eyes with macula-on RRD and fellow eyes. However, in macula-off RRD, MBR remained significantly lower in RRD eyes 6 months postoperatively (P < 0.05). Log-transformed levels of soluble intercellular adhesion molecule-1 (sICAM-1) were negatively correlated with relative MBR (r-MBR, RRD eye/fellow eye) before surgery (r = − 0.47, P = 0.01) in macula-on, but not macula-off, RRD. Six months postoperatively, r-MBR correlated significantly with sICAM-1 levels (r = − 0.36, P = 0.02) in macula-off RRD. ICAM-1 may play a role in RRD-induced deterioration of retinal circulation.

25 vs. 27-gauge micro-incision vitrectomy surgery for visually significant macular membranes and full-thickness macular holes: a retrospective study

BackgroundTo evaluate visual and safety outcomes for 25-gauge (25G) and 27-gauge (27G) micro-incision vitrectomy platforms (MIVS) for the treatment of epiretinal membrane and full-thickness macular holes.MethodsRetrospective analysis of all patients who underwent internal limiting membrane (ILM) peel surgery from January 2017 through December 2018. 207 cases met the eligibility criteria for inclusion. Primary endpoint was post-operative Best-Corrected Distance Visual Acuity (BCVA) at 6 months.ResultsFor all patients combined, mean logMAR BCVA improved from 0.57 (± 0.40) to 0.37 (± 0.36) post-operatively (p < 0.001). For 25G ERMs, logMAR BCVA improved from 0.51 (± 0.28) to 0.30 (± 0.25) post-operatively (p < 0.001). For 27G ERMs, logMAR BCVA improved from 0.33 (± 0.28) to 0.28 (± 0.27) post- operatively (p = 0.15). For 25G FTMHs, logMAR BCVA improved from 0.87 (± 0.48) to 0.51 (± 0.44) post-operatively (p < 0.001). For 27G FTMHs, logMAR BCVA changed from 0.89 (± 0.47) to 0.96 (± 0.60).ConclusionFinal visual outcomes improved for both 25G and 27G ERM groups and the 25G FTMH group. Both 25G and 27G were safe and well tolerated MIVS platforms for the treatment of ERM and FTMH.

Association of retinal vessel density with retinal sensitivity in surgery for idiopathic epiretinal membrane.

The success of surgical treatment for idiopathic epiretinal membrane (ERM) is measured by postoperative best-corrected visual acuity (BCVA), metamorphopsia, andfoveal retinal sensitivity (RS).This study searched for predictive biomarkers of surgical success by determining the association between foveal RS and various aspects of vessel density (VD) in the fovea of patients with ERM. The study examined 25 eyes of 25 patients with ERM who underwent 27-gauge microincision vitrectomy surgery (MIVS). RS was measured with microperimetry (MP-3; NIDEK) at four central points in the fovea with an interpoint distance of 2°. VD was measured with SD-OCT (RS 3000; NIDEK) within the 1-mm2 square defined by the 4 RS points at various depths, including the superficial and deep retinal capillary plexus (SCP and DCP, respectively). Though VD did not change throughout the follow-up period, BCVA and RS significantly improved 1 and 3months after surgery, respectively (both P < 0.0017). Postoperative RS at 6months was positively correlated with postoperative DCP VD at 1, 3, and 6months (r = 0.62, P = 0.001; r = 0.40, P = 0.049; r = 0.53, P = 0.007, respectively), but not with SCP VD at any timepoint. Multiple regression analysis confirmed that postoperative RS at 6months was associated with postoperative DCP VD at 1month (P = 0.03). Higher postoperative DCP VD at 1month contributed to better postoperative foveal RS at 6months. Early postoperative VD in the fovea might be a useful predictive biomarker of late postoperative RS in the fovea in ERM patients.

Efficacy of 27-Gauge Vitrectomy with Internal Limiting Membrane Peeling for Epiretinal Membrane in Glaucoma Patients

Purpose To evaluate the efficacy of epiretinal membrane (ERM) surgery for patients with ERM and glaucoma. Methods We reviewed the medical records of 20 consecutive ERM patients with glaucoma, who underwent 27-gauge microincision vitrectomy surgery (27GMIVS) with internal limiting membrane (ILM) peeling. The preoperative and 6-month postoperative visual field was tested with the Humphrey Field Analyzer (HFA) 24-2 program. Changes in threshold sensitivity in the HFA test points were analyzed point-by-point, with points classified into groups based on sensitivity as abnormal (less than 5th percentile in pattern deviation) or normal (all other points) and based on location as central (12 central points) or peripheral (all other points) with a linear mixed-effects model. Results Visual acuity and mean deviation improved postoperatively (P < 0.001 for both) in all patients. Threshold sensitivity in central or peripheral points that were abnormal preoperatively improved postoperatively (P=0.006 or P < 0.001, respectively). Threshold sensitivity also improved in the central normal test points (P=0.03), but not in the peripheral normal points (P=0.12). Conclusion Visual acuity improved, and there was no visual field progression, after ERM surgery in glaucomatous eyes during a 6-month postoperative follow-up, suggesting that ERM and ILM removal using 27GMIVS may be effective even in glaucomatous eyes.

Prognostic factors of revitrectomy for complications in eyes with proliferative diabetic retinopathy: a retrospective multicentre study.

To identify prognostic factors for revitrectomy in patients who underwent vitrectomy for complications with proliferative diabetic retinopathy (PDR) in multicentre study. Consecutive 452 eyes of 452 patients with PDR undergoing 25-gauge microincision vitrectomy system (MIVS) in seven centres were retrospectivity reviewed. Preoperative ocular factors (baseline visual acuity [VA], vitreous haemorrhage [VH], tractional retinal detachment [TRD] and retinal photocoagulation), general factors (sex, age, diabetes duration, HbA1c level, hypertension, anti-coagulant medication and estimated glomerular filtration rate), surgical procedures (preoperative anti-vascular endothelial growth factor injection, internal limiting membrane peeling, combined cataract surgery, retinal break, and tamponade), postoperative complications for revitrectomy and postoperative VA at 6months were evaluated. In the follow-up period of 6months, revitrectomy was performed in 56 eyes (26.3%), and postoperative complications for revitrectomy were VH in 31 eyes (15%), TRD in 13 eyes (6.2%) and membrane proliferation in 12 eyes (5.2%). The mean LogMAR improvement from baseline to 6months in revitrectomy group (0.39) was significantly worse than in single vitrectomy group (0.74). Diabetic duration, low baseline VA, less simple VH, TRD and air tamponade were statistical risk factors of revitrectomy, and logistic regression analysis identified low baseline VA and air tamponade also as prognostic factors of revitrectomy. Our results indicated that prognosis of VA was worse in PDR patients with revitrectomy and low baseline VA and air as the tamponade material were the potential prognostic factors of revitrectomy.

Comparative study of straight vs angled incision in 27-gauge vitrectomy for epiretinal membrane.

PurposeThe purpose of this study was to compare straight and angled incisions in 27-gauge microincision vitrectomy in patients with epiretinal membrane (ERM).MethodsSeventy-three eyes of 68 patients with ERM who underwent straight (35 eyes) or angled incision (38 eyes) for 27-gauge microincision vitrectomy were retrospectively evaluated.ResultsNo statistically significant difference was found between the two groups in postoperative logarithm of minimal angle of resolution best-corrected visual acuity. The intraocular pressure and rate of hypotony 1 day postoperatively did not differ between the straight- and angled-incision groups (intraocular pressure: 11.5 vs 13.4 mmHg, respectively; rate of hypotony: 20% vs 8%, respectively). Surgical wound closing occurred by postoperative day 10 in both groups.ConclusionA straight incision is as safe and useful in ERM vitrectomy as an angled one.

Retrospective Comparison of 27-Gauge and 25-Gauge Microincision Vitrectomy Surgery with Silicone Oil for the Treatment of Primary Rhegmatogenous Retinal Detachment

Aim To retrospectively compare the safety and effectiveness of 27-gauge (27G) microincision vitrectomy surgery (MIVS) with 25-guage (25G) MIVS for the treatment of primary rhegmatogenous retinal detachment (RRD) with silicone oil tamponade. Methods Ninety-two patients with RRD who underwent MIVS from May 1, 2015, to June 30, 2017, were included in this study. Fifty-eight eyes underwent 25G MIVS and 34 eyes underwent 27G MIVS. We analyzed the characteristics of the patients, surgical time, main clinical outcomes, and rate of complications. Results The mean surgical time was 56.7 ± 35.9 min for the 25G MIVS and 55.7 ± 36.1 min for the 27G MIVS, and there was no significant difference (P=0.894) between the two groups. The primary anatomical success rate after a single operation was 94.8% for 25G MIVS and 91.2% for 27G MIVS (P=0.666). Baseline and final visit best-corrected visual acuity (BCVA) were 1.9 ± 1.1 and 1.0 ± 0.8 in the 25G group, and 1.7 ± 1.0 and 1.1 ± 0.8 in the 27G group. Last visit BCVA increased significantly in both groups (P < 0.001). However, there were no significant differences in terms of visual improvement ratio (>0.2 logMAR) between the two groups (P=0.173). No severe intraoperative complication was observed. Iatrogenic retinal breaks occurred in 2 eyes (3.4%) in the 25G group and 1 eye (2.9%) in the 27G group during the peripheral vitreous base shaving. The transient ocular hypertension (>25 mmHg) within postoperative week 1 was 25.9% in the 25G group and 11.8% in the 27G group (P=0.120). Conclusions This study found no significant anatomical or functional difference between 27G and 25G MIVS in the treatment of primary RRD. Therefore, 27G vitrectomy appears to be a safe and effective surgery for the treatment of primary RRD.

The quantitative assessment of alterations in lens transparency after transconjunctival 27-gauge microincision vitrectomy surgery.

PurposeTo evaluate the baseline and post-vitrectomy lens densitometry values by a Scheimpflug camera in eyes with epiretinal membrane that were treated with 27-G microincision vitrectomy surgery (MIVS) without tamponade and to compare the results with those in fellow healthy eyes.Patients and methodsProspective case series. The lens densitometry measurements of 24 patients, who underwent 27-G MIVS without any tamponade for the treatment of epiretinal membrane, were taken preoperatively and on the first week, first month, and third month postoperatively with Pentacam HR-Scheimpflug imaging system.ResultsThe mean lens densitometry values at Zone 1 and average lens densitometry values significantly increased in the study eyes on the first month when compared with the preoperative values (P=0.011, P=0.033, respectively). Additionally, there were statistically significant differences regarding the mean lens densitometry values of Zone 1 and Zone 2, and also average lens densitometry values between the preoperative and third month postoperative values (P=0.003, P=0.021, P=0.009, respectively). However, the densitometry values of fellow eyes were similar at preoperatively and all the postoperative follow-up periods (P>0.05 for all).ConclusionsThis study suggests that 27-G MIVS might cause post-surgical lens density changes even in early postoperative months and vitreous may play an important role in protecting the transparency of the lens.

Impairment of autoregulation of optic nerve head blood flow during vitreous surgery in patients with hypertension and hyperlipidemia.

To examine whether hypertension (HTN) and hyperlipidemia (HL) affect autoregulation of optic nerve head (ONH) blood flow during vitrectomy. Cohort study. Seventeen eyes from 17 subjects with HTN and HL and 19 eyes from 19 control subjects without systemic disorders underwent vitrectomy for the treatment of epiretinal membrane or macular hole. Following standard 25-gauge microincision vitrectomy, the mean blur rate (MBR), which is an index of relative ONH blood flow, in the vascular area (vascular MBR) and MBR in the tissue area (tissue MBR) were measured using laser speckle flowgraphy. Measurements were conducted before and 5 and 10min after an approximately 15-mmHg rise in intraocular pressure (IOP). Both parameters represent relative values of ONH blood flow (%, compared to baseline). The recovery rate of blood flow to the ONH was calculated using the following equation: (MBR at 10min-MBR at 5min)/(MBR at baseline - MBR at 5min). Ocular perfusion pressure in all subjects was reduced both 5 and 10min after the increase in IOP. Vascular MBR in subjects with HTN and HL (75.5±14.8) was significantly lower than that in control subjects (86.7±12.1) 10min after IOP elevation (P=0.019). The recovery rate of vascular blood flow was significantly lower in the HTN and HL groups than in the control group (P=0.002). Our results suggest that HTN and HL impair autoregulation in the vascular component of ONH blood flow during vitrectomy.

Pars plana posterior capsulectomy with a 27-gauge microincision vitrectomy system for dense posterior capsule opacification

We describe a surgical technique of pars plana posterior capsulectomy using a transconjunctival sutureless 2-port 27-gauge microincision vitrectomy system to deal with dense posterior capsule opacification (PCO). The technique was used successfully in 5 eyes of 5 patients with dense PCO that hadbeen unsuccessfully treated by neodymium:YAG laser photodisruption.

Perioperative changes of the intraocular pressure during the treatment of epiretinal membrane by using 25- or 27-gauge sutureless vitrectomy without gas tamponade.

PurposeThe purpose of this study was to compare perioperative intraocular pressures (IOPs) in 25- or 27-gauge microincision vitrectomy surgery (MIVS) and to evaluate the stability of postoperative sclerotomy closure.Materials and methodsThis is a retrospective review of 147 eyes treated for epiretinal membrane by using 25- or 27-gauge MIVS as the initial vitrectomy (25-gauge phacovitrectomy [25-P group]: 73 eyes, 25-gauge vitrectomy alone [25-A group]: 15 eyes, 27-gauge phacovitrectomy [27-P group]: 47 eyes, and 27-gauge vitrectomy alone [27-A group]: 12 eyes). Statistical analyses of perioperative IOPs on preoperative day (PreOp), postoperative day (POD)1, POD2, postoperative week 1, and postoperative month 1 were performed.ResultsAll self-sealing sclerotomies were obtained without gas tamponade at the end of surgery. Also, no significant differences were noted in the age and axial length among the 4 groups and in the surgical time between 25-P and 27-P groups and between 25-A and 27-A groups. Significant decreases in IOP were found at POD1 and POD2 in the 25-P, 25-A, and 27-P groups compared with PreOP, but not in the 27-A group.ConclusionEven though surgeons confirm that there is no leakage from sutureless sclerotomy and that a normal IOP is preserved at the end of 25- or 27-gauge MIVS, there is a possibility of postoperative sclerotomy leakage on the day of the surgery. Furthermore, postoperative sclerotomy self-sealing of the MIVS in previous intraocular lens implantation cases is considered to be acquired easily than that in phacovitrectomy.

Evaluation of corneal topographic changes and surgically induced astigmatism after transconjunctival 27-gauge microincision vitrectomy surgery.

To evaluate the corneal topographic changes and postvitrectomy astigmatism after 27-gauge (g) microincision vitrectomy surgery (MIVS) by using Pentacam HR-Scheimpflug imaging system. This prospective descriptive study included 30 eyes of 30 patients who underwent 27-g MIVS. All eyes underwent a Pentacam HR examination preoperatively and on the first week, first month and third month postoperatively. The power of the corneal astigmatism, mean keratometry (K m), K 1 and K 2 values and corneal asphericity (Q value) values for the both front and back surfaces of the cornea, index of surface variance (ISV), index of vertical asymmetry (IVA), index of height asymmetry (IHA), index of height decentration (IHD) and higher-order aberrations including coma, trefoil, spherical aberration, higher-order root-mean-square and total RMS were recorded. Additionally, the mean induced astigmatism was estimated by vector analysis. No statistically significant changes were observed in the mean power of corneal astigmatism, mean keratometry, K 1 and K 2 values, corneal asphericity values, ISV, IVA, IHA, IHD and higher-order aberrations on the first week, first month and third month after the operation. The mean surgically induced astigmatism was calculated as 0.23±0.11 D on the first week, 0.19±0.10 D on the first month and 0.19±0.08 D on the third month postoperatively. Minor corneal surface and induced astigmatic changes are expected to result in rapid visual rehabilitation after pars plana vitrectomy with the 27-g MIVS system.

Outcomes of transconjunctival sutureless 27-gauge micro-incision vitrectomy surgery in diabetic vitreous haemorrhage.

Objective:To evaluate the visual outcomes of 27-gauge transconjunctival sutureless vitrectomy surgery and its complications in patients with diabetic vitreous hemorrhage.Methods:A quasi-experimental study was conducted where eighty seven eyes of 87 uncontrolled type II diabetes mellitus patients presenting with diabetic vitreous hemorrhage were selected to undergo 27-gauge transconjunctival sutureless micro-incision vitrectomy surgery. Main outcome measured was best corrected visual acuity (BCVA). Post-operative complications were also screened for at each visit. The follow ups were at post-operative day one, one month, three months and six months respectively.Results:Out of 87 patients, 52 (59.8%) were males and 35 (40.2%) were females. The mean age of the patients was 52.32 ± 6.78 years (95% CI: 53.13 - 55.57). For most of the patients, the BCVA improved progressively with each subsequent follow up visit. Pre-operative BCVA was 1.01 ± 0.206 logMar, compared to BCVA at final follow up of 0.44 ± 0.231 (p-value < 0.001). Six (6.9%) patients developed recurrent vitreous hemorrhage during the study period, four (4.6%) developed cataract, one (1.1%) had increased intraocular pressure and sub conjunctival hemorrhage was present in two (2.3%).Conclusion:27-gauge micro-incision vitrectomy surgery is an effective sutureless surgery with favorable outcomes, in terms of vision, in patients with diabetic vitreous hemorrhage. The associated complications are few which can be easily managed.

27-gauge microincision vitrectomy surgery system for clinical application

Objective To observe the preliminary clinical results and safety of 27-gauge microincision vitrectomy surgery for partial vitreoretinal diseases. Methods A total of 13 patients (13 eyes) who underwent 27-gauge microincision vitrectomy surgery were enrolled. The follow-up period was 6 to 12 months. Preoperative and postoperative visual acuity and intraocular, total operative time, cutting time for removing vitreous, wound healing status, intraoperative and postoperative complications were observed. Results Mean best corrected visual acuity improved from preoperative (1.26±0.66) logMAR (0.10±0.09) to postoperative (0.63±0.52) logMAR (0.35±0.24), and the difference was statistically significant (t=2.743, P=0.018). The difference of mean preoperative intraocular pressure (IOP), IOP of postoperative day 1, day 5, one month and final postoperative visit were not statistically significant (F=0.593, P>0.05). The mean total operative and cutting times were (36.38±14.97) min and (10.12± 3.54) min respectively. Postoperative scleral incision showed linear closure, no cases of postoperative sclerotomy-related complications such as wound dehiscence, vitreous incarceration and subconjunctival fluid were observed. No intraoperative and postoperative complications of iatrogenic retinal breaks, endophthalmitis, choroidal detachment, retinal detachment and vitrous hemorrhage were observed. Conclusions The 27-gauge microincision vitrectomy surgery can improve postoperative visual acuity for treatment of vitreoretinal diseases and induce fewer sclerotomy-related complications, which maybe a safer surgical approach. Key words: Vitrectomy; Microincision; Clinical efficacy