Advancements of vitreoretinal surgical machines

Surgical strategy and outcome in patients with bilateral proliferative diabetic retinopathy

OBJECTIVES

To investigate the current surgery strategies for bilateral proliferative diabetic retinopathy (PDR), as well as the surgical outcomes of patients with bilateral PDR who underwent pars plana vitrectomy (PPV).

MATERIALS

Patients undergoing bilateral vitrectomy for PDR from January 2019 to December 2020 at The Eye Hospital of Wenzhou Medical University were enrolled. Clinical data were collected from the electronic medical records. Factors associated with the time interval between the surgeries on two eyes and postoperative visual outcomes were analyzed.

RESULTS

In total, 152 patients with bilateral PDR who underwent bilateral PPV were included in this analysis. Mean age was 53.7 ± 11.4 years. Compared with second-surgery eyes, 60.5% of first-surgery eyes had worse preoperative best-corrected visual acuity (BCVA). The overall PPV time (median, quartile range) between first and second surgeries eye was 1.40 (0.70, 3.15) months. Multivariate analysis showed that the preoperative BCVA of the second-surgery eye had a significant effect on the inter-surgery time interval (P = 0.048). First-surgery eyes had greater vision improvement than second-surgery eyes (Difference of the logarithm of the minimum angle of resolution [LogMAR] BCVA: - 1.00 [- 1.48, - 0.12] versus 0.00 [- 1.30, 0.00], respectively, P < 0.001), especially when eyes with poorer BCVA underwent PPV first (- 1.15 [- 1.87, - 0.54] versus 0.00 [- 0.70, 0.00], respectively, P < 0.001).

CONCLUSIONS

Visual acuity is a significant factor that influences surgical strategies, including both surgery order and interval, for patients with bilateral PDR. The eyes operated upon first show more vision improvement due to prompt surgery.

THREE-DIMENSIONAL HEADS-UP VITRECTOMY VERSUS CONVENTIONAL MICROSCOPIC VITRECTOMY FOR PATIENTS WITH EPIRETINAL MEMBRANE

PURPOSE

To investigate the efficacy and safety of 3D heads-up display (3D-HUD) vitrectomy compared with conventional microscopy (CM) vitrectomy in epiretinal membrane (ERM) surgery.

METHODS

Epiretinal membrane removal with or without internal limiting membrane (ILM) peeling was performed using a 3D-HUD or CM system. The mean changes in best-corrected visual acuity (BCVA) and in central macular thickness (CMT) and postoperative complications were assessed.

RESULTS

Baseline demographics were comparable except for the follow-up period. Both BCVA and CMT improved at the final visit (all P < 0.05). The ERM recurrence and dissociated optic nerve fiber layer (DONFL) rates were lower in the 3D group (both P < 0.05). conventional microscopic vitrectomy (odds ratio [OR] = 12.86, P = 0.02) and absence of ILM peeling (OR = 45.25, P < 0.05) were associated with ERM recurrence. In the DONFL, CM vitrectomy (OR = 1.98, <0.05) and combined phacovitrectomy (OR = 2.33, P = 0.03) were analyzed as risk factors for DONFL.

CONCLUSION

The improvement in BCVA and CMT in ERM surgery using a 3D-HUD is comparable with that of CM vitrectomy, with a significantly low rate of ERM recurrence and DONFL occurrence. Therefore, 3D vitrectomy might have an advantage for ERM surgery.

Long-Term Safety and Efficacy of Pars Plana Vitrectomy for Uveitis: Experience of a Tertiary Referral Centre in the United Kingdom

AIM

To evaluate the effectiveness of pars plana vitrectomy (PPV) without macular intervention on uveitis eyes with persistent vitreous inflammation/opacities in terms of visual acuity (VA), intraocular inflammation and macular profile.

METHODS

We carried out a single-center retrospective study of patients with uveitic eyes that underwent PPV without intervention on the macula due to persistent vitreous inflammation/opacities. The primary outcome measures were best-corrected visual acuity (BCVA), intraocular inflammation and macular profile at 3, 12 and 24 months after surgery.

RESULTS

Twenty-seven eyes of twenty-six patients were analyzed. Overall, 77.8% had an improvement of VA (55% by 0.3 LogMAR or more); 62.5% of patients had no intraocular inflammation, and the number of patients on systemic steroids and second-line immunosuppressives was reduced by 26% at 12 months; 87.5% of patients had resolution of macular oedema at 12 months.

CONCLUSION

PPV for persistent vitreous inflammation/opacities is safe and effective, showing beneficial outcomes in terms of improvement of BCVA and the reduction in inflammation.

Intraocular reflectance of the ocular fundus and its impact on increased retinal hazard

PURPOSE

Inside the eye light can be reflected multiple times due to light-tissue interactions and the spherical geometry of the eye. Due to these optical properties, a defined retinal area is not only illuminated by direct light but also by indirect, reflected light from the inner side of the eyewall. During illumination for ophthalmic surgery, this could lead to an unintended increase in intraocular retinal irradiance, which was already discussed in previous studies but without a detailed consideration of spectral differences and a potential influence of pigmentation. In this study this effect is investigated wavelength-dependent to see if different wavelengths lead to different increase in irradiance, with a special focus on the raise in photochemical and thermal hazard to the retina. It is also examined whether this effect is dependent on the pigmentation of the eye.

METHODS

The reflectance properties of either less or highly pigmented porcine eyes are measured in the wavelength range between 350 and 1100nm with an integrating sphere and a spectrometer. With these reflectance spectra the wavelength-dependent Sphere Multiplier M of porcine eyes can be calculated, which represents the increase of radiance due to multiple reflections inside a sphere compared to a planar diffuser of the same size. Based on measurements of the emitted irradiance of ophthalmic illumination fibers the increase in photochemical and thermal retinal hazard due to these multiple reflections is calculated for eyes with small and high amounts of pigmentation.

RESULTS

The reflectance of the inner eyewall in the range between 350 and 1100nm is significantly higher for eyes with low pigmentation (between 4.90% and 37.44% reflectance) in comparison to eyes with a high amount of pigmentation (between 4.30% and 28.88% reflectance). The Sphere Multiplier for the inner side of the eyewall (sclera, choroid and retina) ranges between 1.13 and 1.59 and between 1.13 and 1.48 for eyes with low and high pigmentation, respectively, in the range between 350 and 1100nm. The reflectance, as well as the Sphere Multiplier, is strongly wavelength-dependent due to the absorption spectra of melanin and hemoglobin, which are located in the eye. With increasing wavelength, the reflection properties and the Sphere Multiplier also increases. With this, the photochemical retinal hazard of highly pigmented eyes increases by (14.11± 0.09)% and of lightly pigmented eyes by (16.75±0.35)% compared to if the reflection properties are not considered. The thermal retinal hazard increases by (14.30±0.07)% for highly pigmented eyes and by (19.65±0.17)% for low pigmented eyes.

CONCLUSION

This study demonstrates that the anatomy and pigmentation of the eye plays an important role for the reflectance properties of the eye and for the photochemical and thermal hazard to the retina.

Nationwide Trends in Vitreoretinal Procedures within Australia

PURPOSE

To investigate Australian age stratified nationwide trends in vitreoretinal procedures.

METHODS

Nationwide retrospective analysis of vitreoretinal procedures in Australia over 2001-2019 using Australian National Hospital Morbidity Database for public and private hospitals. Age and gender-specific trends in selected procedures including pars plana vitrectomy for retinal detachment (PPV for RD), scleral buckle, intravitreal injections, and PPV unrelated to RD were analysed using negative binomial regression.

RESULTS

Total included procedures increased from 8102 in 2001 to 136430 in 2019. Between 2001 and 2019, the incidence per 100,000 persons of PPV for RD increased from 7.5 to 20.7, whilst scleral buckling decreased from 10.5 to 4.0. Similarly, the incidence per 100,000 persons of PPV unrelated to RD increased from 18.4 to 67.1, and intravitreal injections increased from 5.6 to 446.0. The rate of scleral buckling decreased by 6% annually (p < .001), most pronounced in those 40 years and above. In contrast, PPV for RD increased by 5% annually (p < .001), also most pronounced in those aged 40 and above. PPV unrelated to RD increased by 7% annually (p < .001), and intravitreal injections increased by 210% annually (p < .001).

CONCLUSION

Between 2001 and 2019, the rate of scleral buckling declined compared to an increase in PPV for RD. Our analysis suggests an increasing trend to PPV over scleral buckling for RD repair in Australia over the last two decades. Additionally, rates of PPV unrelated to RD and intravitreal injections increased across all age groups. Overall, these trends mirror those seen internationally and reflect changing practice patterns over time.

Clinical outcomes of a beveled tip, ultra-high speed, 25-gauge pars plana vitrectomy system

Objective

To report the clinical outcomes of a 25-gauge, beveled-tip, 10,000 cuts-per-minute (cpm) microincisional vitrectomy surgery (MIVS) system.

Methods

Prospective case series of eyes undergoing primary pars plana vitrectomy (PPV) for common vitreoretinal indications. Main outcome measures were: rate of achieving surgical objectives, operative times, number of surgical steps, use of ancillary instruments, corrected distance visual acuity (CDVA), and adverse events (AE).

Results

The surgical objectives were achieved in all eyes. Mean total operative time (TOT), core, shave and total vitrectomy times were 1891 ± 890, 204 ± 120, 330 ± 320, 534 ± 389 s, respectively. Mean number of surgical steps was 4.3 ± 1.5. Mean number of ancillary instruments used was 4.5 ± 1.9. Mean CDVA improved by 0.53 ± 0.56 logMAR units (P < 0.001) 3 months postoperatively. AE included elevated IOP (8%), hypotony (6%), and re-detachment (2%). Majority (82%) had no postoperative discomfort. The number of surgical steps demonstrated a positive correlation with TOT (p < 0.05), number of ancillary instruments used (p < 0.05), and postoperative Day 1 IOP (p < 0.05). The number of times ancillary instrumentation was used demonstrated a positive correlation with TOT (p < 0.05).

Conclusion

Beveled-tip, 10,000 cpm MIVS system effectively and safely performs common VR procedures of varying complexity and may reduce operative times and use of ancillary instrumentation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-022-02311-3.

Comparisons of flow dynamics of dual-blade to single-blade beveled-tip vitreous cutters

INTRODUCTION

To compare the flow dynamics of the dual-blade to the single-blade beveled-tip vitreous cutters.

METHODS

The aspiration rates of balanced salt solution (BSS) and swine vitreous were measured for the 25-gauge and 27-gauge dual- and single-blade vitreous cutters. The flow dynamics of BSS and diluted vitreous mixed with fluorescent polymer at the maximal cutting rates and the reflux of BSS were measured in images obtained by a high-speed camera. The distal end of the cutter was defined as the head end.

RESULTS

The aspiration rates of BSS and vitreous by the 25- and 27-gauge dual-blade cutters were significantly higher than those of both single-blade cutters at the maximal cutting rate (all P≤0.01). The mean aspiration flow of BSS in front of the port from a lateral view was significantly faster for both dual-blade cutters than for both single-blade cutters (P=0.003, P=0.019). The angle of the mean flow of BSS of both dual-blade cutters was from the distal end (P<0.001, P<0.001) but that of the single blade-cutters was from the proximal end. The velocity and angle of the mean reflux flow of both types of cutters were not significantly different. The mean aspiration flow of diluted vitreous was significantly faster for 25-gauge dual-blade cutters with the angle more from the proximal end and 27-gauge dual-blade cutters more from the distal end than both single-blade cutters (P=0.018, P=0.048).

CONCLUSION

The dual-blade beveled-tip vitreous cutters improve the efficiency of the vitrectomy procedures and maintain the distal aspirating flow by the beveled-tip.

In Vitro Comparison of Various High-Speed Vitrectomy Machines Using Dual Blade Cutters

Objectives

The objective of this study is to compare various dual blade vitrectomy cutters for their efficiency in an in vitro setting.

Methods

In this in vitro experimental study, we compared various vitrectomy systems including EVA (Dutch Ophthalmic Research Center, Zuidland, The Netherlands), REVOLUTION (Optikon 2000, Inc., Rome, Italy), and OS4 (Oertli Instrumente AG, Berneck, Switzerland) in terms of efficiency in vitreous cutting and aspiration for various vitreous substitutes. These substitutes included water, chicken egg albumin, and goat vitreous. We only used 23-gauge dual blade cutters across all platforms to maintain uniformity. The cutting and aspiration efficiency was measured across various cut and vacuum settings of vitrectomy machines and measured as mass aspirated in a given time. Data analysis included comparing the amount of mass aspirated by these machines at preset cut and vacuum settings.

Results

Scatter plots showed a comparable mass of water aspirated by the EVA and REVOLUTION at 1000 to 5000 cuts per minute at a constant vacuum of 500 mm Hg whereas OS4 aspirated lesser mass at similar settings. Same trends were noted for goat vitreous for EVA and REVOLUTION but aspirated mass of albumin fluctuated widely across various platforms. At peak machine settings, REVOLUTION showed superiority across all three vitreous models due to its higher peak settings. The area under curve (AUC) analysis showed no significant differences among machines for water and goat vitreous at comparable settings but results were fluctuating for egg albumin.

Conclusion

Employing higher cut rates for dual blade cutters results in better efficiency of vitrectomy machines.

To estimate the safety and efficacy of a 3-D visualization helmet for vitreoretinal surgery

PURPOSE

To evaluate a 3-D visualization helmet (3DVH) during 23-gauge pars plana vitrectomy (PPV) for macular holes (MH) and macular puckers (MP).

METHODS

A total of 184 eyes of 184 patients undergoing PPV for MH or MP were randomly selected for surgery with 3DVH or standard Galilean microscope (GM). Only one highly trained surgeon performed each PPV. A surgical comfort score, ranging from 1 to 10 was recorded after each operation. Statistical analysis was run with SPSS to compare parameters before and after surgery and between the two groups.

RESULTS

No statistical differences were found between the two groups for mean best correct visual acuity improvement after surgery (p < 0.001). Mean surgery comfort evaluation was 7.63 ± 0.48 in 3DVH eyes and 8.21 ± 0.62 in GM ones (p = 0.09); mean overall surgical time was 35.12 ± 3.8 min in 3DVH eyes and 32.7 ± 2.27 min in GM ones (p < 0.001); mean peeling time was 14.24 ± 3.42 min in 3DVH eyes and 13.61 ± 4.63 min in GM ones (p = 0.11).

CONCLUSIONS

According to the data observed in this study, the 3DVH provides adequate safety and efficacy in retinal and macular visualization during PPV for MH and MP.

FLOW DYNAMICS OF BEVELED-TIP AND FLAT-TIP VITREOUS CUTTERS

PURPOSE

To compare the flow dynamics of beveled-tip to that of flat-tip vitreous cutters.

METHOD

The aspiration rates of balanced salt solution and swine vitreous were measured for 25-gauge and 27-gauge beveled-tip and flat-tip vitreous cutters. Fluorescent polymer microspheres were mixed with balanced salt solution to make the flow visible. The flow dynamics at maximal cutting rates and reflux of balanced salt solution were measured with video images of a high-speed camera.

RESULTS

The aspiration rates of balanced salt solution of the 25-gauge and 27-gauge beveled-tip cutters were significantly higher than that of the flat-tip cutters at 7,500 cut/min (P = 0.0001, P = 0.038, respectively). The aspiration rate of swine vitreous by the 25-gauge beveled-tip cutter was significantly higher than that of the flat-tip cutters (P = 0.006). The mean aspiration flow in front of the cutter was significantly faster for both beveled-tip than flat-tip cutters (P = 0.003, P = 0.023). The angle of the mean aspiration flow of both beveled-tip cutters was turned to the proximal side (P = 0.004, P = 0.003). The mean reflux flow of both beveled-tip cutters was significantly faster than that of the flat-tip cutters (P = 0.006, P = 0.006).

CONCLUSION

The beveled-tip cutters have a greater velocity of aspirating frontal and proximal flow resulting in higher aspiration rates and greater reflux flow velocity.

Clinical comparison of 27-gauge and 23-gauge instruments on the outcomes of pars plana vitrectomy surgery for the treatment of vitreoretinal diseases

PURPOSE OF REVIEW

To compare outcomes of 27-gauge and 23-gauge pars plana vitrectomy (PPV) for treatment of vitreoretinal diseases.

RECENT FINDINGS

Sixty-eight patients undergoing microincisional PPV for treatment of vitreoretinal diseases were randomized 1 : 1 to 27-gauge or 23-gauge surgery with a 7500 cuts-per-minute vitrectomy probe. The most common reasons for vitrectomy were epiretinal membrane (49%) and vitreous hemorrhage (24%). Mean ± standard deviation (SD) changes from immediate preoperative to immediate postoperative intraocular pressure were -0.40 ± 6.60 mmHg in the 27-gauge and -3.05 ± 7.64 mmHg in the 23-gauge group (adjusted mean difference 2.42 mmHg, 95% lower confidence limit 0.64, P = 0.013), but these changes were not associated with primary reason for vitrectomy (P = 0.065). Mean ± SD conjunctival edema grades in the 27-gauge and 23-gauge groups 1 week after surgery were 0.02 ± 0.124 and 0.10 ± 0.246, respectively (least squares mean difference -0.09, 95% upper confidence limit -0.03, P = 0.004), and were 0.01 ± 0.122 and 0.12 ± 0.338, respectively, at the probe incision site. Conjunctival edema grades were similar in both groups at 1 and 3 months. Mean ± SD pain ratings on postoperative day 1 - an indicator of patient comfort - were similar in the two groups.

SUMMARY

Smaller diameter vitrectomy instruments are associated with smaller reductions in immediate postoperative intraocular pressure.

Hybrid 23/27 Gauge Vitrectomy - Combining the Charm of 27G with the Efficacy of 23G

Background

Minimally invasive transconjunctival sutureless vitrectomy (MIVS) has evolved into the standard of care, smaller incisions thought to result in lower ocular surface trauma and shorter times to recovery. The currently most relevant limitations in macular surgery may be light intensity and 27G instrument stability. Therefore, we thought to compare standard 23 and 27G vitrectomy with a hybrid technique using one 23G and two 27G ports regarding surgical times and short-term outcomes.

Methods

This retrospective comparison included 90 single-center consecutive cases of eyes undergoing elective micro-invasive vitrectomy for epiretinal membranes or idiopathic macular holes between October 2017 and June 2018. The main criteria for the comparison were total surgical time as primary outcome parameter and treatment-demanding intra- and postoperative complications along with recovery of best-corrected visual acuity (BCVA) and central retinal thickness (CRT) from prior to surgery to 1 month thereafter as secondary parameters as independent parameters for the recovery from the pre-existing pathology and the surgical trauma.

Results

Surgical times were shorter with 23G and 23/27G compared to 27G (23G: 38.4±13.1; 27G: 48.1±15.3; 23/27G: 34.9±9 mins; p=0.0005) with no differences in BCVA and CRT outcomes. Switching from 27G to a larger port size was not necessary in any instance. Cryotherapy was applied in 15%, 30%, and 22.5% to suspected retinal pathologies, beyond these, in 5%, 0%, and 7.5% for retinal tears. Four postoperative retinal detachments occurred (4.4%), one in the 23G and three in the 23/27G group requiring re-vitrectomy.

Conclusion

In this exploratory case series, 23/27G hybrid vitrectomy, combining the advantages of 23G and 27G techniques, resulted in shorter surgical times without evident disadvantages. The combination with cataract surgery was unproblematic.

Comparison of a Three-Dimensional Heads-Up Display Surgical Platform with a Standard Operating Microscope for Macular Surgery

PURPOSE

To assess safety, efficacy, and outcomes of vitreoretinal surgery for macular pathology using a 3-dimensional heads-up display (3D HUD) surgical platform compared with a standard operating microscope (SOM).

DESIGN

Prospective, single-center, unmasked, randomized study.

PARTICIPANTS

Patients undergoing pars plana vitrectomy (PPV) for epiretinal membrane (ERM) or full-thickness macular hole (MH) at Wills Eye Hospital.

METHODS

Patients were randomized 1:1 to undergo surgery with a 3D HUD surgical platform or SOM. Patients who had previous PPV were excluded. Surgical choices, including PPV gauge, were based on surgeon preference. Standard surgical safety parameters, Early Treatment Diabetic Retinopathy Study visual acuity (VA), minimum required endoillumination levels, operative times, and surgeon "ease of use" of the viewing platform were recorded. Patients were followed up to postoperative month 3 (POM3).

MAIN OUTCOME MEASURES

The main outcome measures were total operative time, macular peel time, surgeon rating of viewing system ease of use, minimum required endoillumination, intraoperative complication rate, and postoperative VA.

RESULTS

Thirty-nine eyes of 39 patients with a mean age of 67.60±8.21 SD years were enrolled. Indications included ERM (n = 26 [3D HUD = 14, SOM = 12]) and MH (n = 13 [3D HUD = 9, SOM = 4]). Minimum required endoillumination was significantly lower with 3D HUD (mean 22.70%±15.10% SD) compared with SOM (mean 39.06%±2.72%; P < 0.001). There was no significant difference in overall operative time, but macular peel time was significantly longer using 3D HUD (mean 14.76±4.79 minutes) than SOM (11.87±8.07 minutes; P = 0.004). Surgeon-reported ease of use was significantly higher (easier) using SOM compared with 3D HUD (P = 0.004). There was no statistically significant difference between the groups in POM3 logarithm of the minimum angle of resolution (logMAR) VA or change in logMAR VA from baseline (all P > 0.681). There were no clinically significant intraoperative complications in either group.

CONCLUSIONS

Three-dimensional heads-up display surgical visualization is an evolving technology demonstrating comparable efficacy to the SOM for macular surgery. Although overall surgical times were similar, 3D HUD macular peel times were longer and associated with less ease of use in this study, which may partly be due to a learning curve with new technology.

Surgical outcomes of 27-gauge and 25-gauge vitrectomy day surgery for proliferative diabetic retinopathy

PURPOSE

To compare postoperative outcomes of 27-gauge (G) and 25-G vitrectomy conducted as day surgery for proliferative diabetic retinopathy (PDR).

METHODS

One hundred eighty-five consecutive PDR patients (185 eyes) who underwent primary vitrectomy (27-G in 64 eyes, 25-G in 121 eyes) were analyzed.

RESULTS

The 27-G and 25-G groups did not differ significantly in preoperative Early Treatment Diabetic Retinopathy Study (ETDRS) score, age, or preoperative intraocular pressure. The proportions of simultaneous cataract surgery (27-G vs. 25-G: 59.4% vs. 62.4%) and air-filled eyes (76.6% vs. 85.1%) were not significantly different between two groups. Both groups showed significant improvement in ETDRS score at postoperative 1, 3, and 6 months (all, P < 0.0001). Mean gain in ETDRS score from baseline was apparently better in 27-G group than in 25-G group at 1, 3, and 6 months, but there were no significant differences (1 month: 20.3 vs. 13.1 letters, P = 0.0703; 3 months: 22.9 vs. 17.5 letters, P = 0.1561; 6 months: 24.3 vs. 19.3 letters, P = 0.3313). Operation time was apparently longer for 27-G vitrectomy, but there was no significant difference (54.0 vs. 51.1 min, P = 0.3676). The same was observed for postoperative intraocular pressure at postoperative day 1 (19.7 vs. 18.1 mmHg, P = 0.1353). Incidence of postoperative retinal detachment (1.6% vs. 0.8%) and reoperation due to vitreous hemorrhage (6.3% vs. 6.6%) was not different between two groups.

CONCLUSIONS

The 27G system is as safe and as useful as the 25G system when used for PDR and can be expected to achieve earlier recovery of postoperative visual acuity.