Illumination and Phototoxicity Issues in Vitreoretinal Surgery

Evaluation of the (Baha) technique of scleral indentation using a self-retained scleral indenter during vitrectomy surgery: a randomized trial

AIMS

The current study compared a novel technique of scleral indentation using the self-retaining Leyla retractor to the conventional scleral self-indentation with the chandelier light.

METHODS

Patients with rhegmatogenous retinal detachment were randomized on a 1:1 basis to either have the (Baha) indentation using a tip of a thimble scleral indenter welded to the support for the Leyla retractor system or to have the conventional scleral indentation while using a 25-gauge chandelier light. A video was recorded for the surgery of all the cases and reviewed by another consultant masked to the type of indentation. The indentation duration (i.e., the time in seconds between the first appearance of a hump due to scleral indentation in the recorded video until its final disappearance) was measured for every case.

RESULTS

The current study included 60 eyes of 60 adults with a mean age of 59.6 ± 9.8 years. Thirty-nine of the eyes were phakic and 21 were pseudophakic. The mean indentation time was 618 ± 87 and 696 ± 72 s in (Baha) indentation and conventional indentation groups, respectively. The difference was not statistically significant (p = 38). There was a positive correlation between the vertical palpebral fissure height and the indentation duration for both (Baha) indentation (r = 0.58) and conventional indentation groups (r = 0.42). Readjustment of the chandelier endo-illumination was required in 19 cases (63.3%) in the conventional indentation group. Iatrogenic breaks or accidental crystalline lens touch did not occur in any case.

CONCLUSION

The (Baha) technique is effective and safe, especially in patients with a larger palpebral fissure.

Outcomes of vitreoretinal surgery in eyes with retinitis pigmentosa without retinal detachment

PURPOSE

Outcomes of retinal detachment (RD) have been discussed in detail in many reports of patients with retinitis pigmentosa (RP). This study tries to understand the outcomes of vitreoretinal (VR) surgery for indications other than RD in the eyes with RP.

METHODS

This is a retrospective study that includes clinical data from January 2013 to December 2021. Patients with RP who were treated with a VR surgical intervention were included in the study. The primary outcome of the study was to assess the changes in best-corrected visual acuity.

RESULTS

Forty-four eyes of 40 patients with RP were included in the study. Nearly half of the eyes (43%, 19/44) presented from 1 month to 1 year after the onset of diminished vision, with or without floaters. The mean ± standard deviation (SD) best-corrected visual acuity (BCVA) at presentation was 1.30 ± 0.79 logMAR (20/400 ± 20/125). The major surgical indications were vitreous opacities (43.2%, 19/44) and subluxated/dislocated cataractous lenses (25%, 11/44). The median follow-up duration was 8 months (interquartile range (IQR): 1.5-27). Approximately 77% (34/44) of the eyes had improvement in vision. The mean postoperative BCVA at the last follow-up was 0.95 ± 0.73 logMAR (p-value: 0.03).

CONCLUSIONS

Most eyes with RP recovered well after VR surgical interventions, with short-term improvements in visual acuity. It may be crucial to address the vitreous opacities and membranes as they hinder the residual central island of vision in RP. However, appropriate counselling is required regarding the progressive nature of retinal neuronal degeneration.

Use of a three-dimensional head-mounted digital visualization platform in cataract surgery

OBJECTIVE

To report preliminary experience using the BeyeonicsOne (Beyeonics Vision, Haifa, Israel) digital visualization platform and the utilization of its three-dimensional (3D) head-mounted display (HMD) in cataract surgery.

METHODS

An interventional case series including patients who underwent cataract surgery using the 3D HMD platform at the Tel Aviv Medical Center. The system uses the HMD unit to display high-resolution real-time 3D surgical field images. Collected data included patient demographics, ocular comorbidities, risk factors for complex cataract surgery, cataract grading, preoperative and postoperative best-corrected visual acuity (BCVA), and intra- and postoperative complications.

RESULTS

In total, 60 eyes of 60 subjects (mean age 73.1 ± 8.4 years) were included. Mean preoperative BCVA was 0.40 ± 0.30 logMAR (Snellen equivalent ~20/50) and improved to 0.10 ± 0.10 logMAR (Snellen equivalent ~20/25, p < 0.001). None of the patients suffered BCVA loss. All procedures and follow-ups were uneventful except for one case of a posterior capsular tear and one case of post-surgical cystoid macular edema.

CONCLUSION

The visualization platform and its embedded 3D head-mounted display can be easily used in routine cataract surgery with the added benefits of improved ergonomics, high picture quality and enhanced image control.

Determination of Correlated Color Temperature in Ex Vivo Porcine Eyes during Intraocular Illumination

(1) Background: In ophthalmic surgery, white light is mostly applied to illuminate the intraocular space, and ophthalmologists are comfortable working with it. Diaphanoscopic illumination changes the spectral composition of light, resulting in a change in the correlated color temperature (CCT) of the intraocular illumination. This color change makes it difficult for surgeons to recognize the structures in the eye. CCT during intraocular illumination has not yet been measured before, and it is the aim of this study to perform such measurement. (2) Methods: CCT was measured inside ex vivo porcine eyes during diaphanoscopic illumination and endoillumination using a current ophthalmic illumination system with a detection fiber inside the eye. By applying pressure on the eye with a diaphanoscopic fiber, the dependency of CCT on pressure was examined. (3) Results: The intraocular CCT values during endoillumination were 3923 K and 5407 K for the halogen and xenon lamps, respectively. During diaphanoscopic illumination, a strong unwanted red shift was observed, resulting in 2199 K and 2675 K for the xenon and the halogen lamps, respectively. Regarding different applied pressures, the CCT did not differ considerably. (4) Conclusions: This red shift should be compensated for in the development of new illumination systems since surgeons are used to white light illumination, which also simplifies the identification of retinal structures.

Retinal risk of endoillumination: A comparison of different ophthalmic illumination systems

OBJECTIVES

In vitreoretinal surgery, there is always a conflict between bright illumination of the field of operation and retinal safety. This study aimed to investigate different light sources and light guides for their potential retinal risk due to bright illumination.

METHODS

Irradiances in the fovea of ex-vivo porcine eyes resulting from different light sources (halogen lamp, xenon lamp and LED) and light guides are investigated for varying distances between the illumination tip and the fovea. The results are examined with regard to their photochemical and thermal retinal hazard and the maximal exposure time. The examination is carried out with the maximum intensity setting of each light source and with normalization to its brightness.

MAIN RESULTS

With decreasing distance of the tip of the light source, the retinal hazard increases. The photochemical and thermal retinal hazard at maximum brightness are smallest for the halogen lamp, next for the xenon lamp and highest for the LED. Thus, the exposition time is the longest for the halogen lamp followed by the xenon lamp and the LED. Normalizing the results to the same brightness the maximum exposition time is nearly the same for xenon lamp and LED, but still higher in case of the halogen lamp.

CONCLUSIONS

The choice of the most suitable lamp and illumination fiber depends on the intensity and spectral distribution of the illumination system. Concerning brightness, xenon and LED lamp are relatively harmless, but the surgeon should avoid the maximum device intensity.

Membrane Blue Dual Protects Retinal Pigment Epithelium Cells/Ganglion Cells-Like through Modulation of Mitochondria Function

Although recent data highlight the greater protective effects exerted by Membrane Blue Dual (MBD), a precise analysis of the mechanisms of action is missing. We examined the effects of MBD with/without polyethylene glycol (PEG) on both human retinal pigment epithelial cells (ARPE-19) and retinal ganglion cells-like (RGC-5) cultured in the presence/absence of ultraviolet B (UVB) treatment on mitochondria function, oxidants, and apoptosis. In ARPE-19/RGC-5 cells either treated or not with UVB, the effects of MBD with/without PEG were evaluated by specific assays for viability, mitochondrial membrane potential and mitochondrial reactive oxygen species (mitoROS) release. Annexin V was used to detect apoptosis, whereas trypan blue and the scratch assay were used for proliferation/migration. In both physiologic conditions and in the presence of UVB, MBD with/without PEG increased cell viability, mitochondrial membrane potential, proliferation and migration in both ARPE-19 and RGC-5 cells. In general, the effects of MBD with PEG were greater than those caused by MBD without PEG. Our results suggest that, in particular, MBD with PEG is a safe and effective dye for vitreoretinal surgery through the modulation of mitochondrial function.

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.

Pars Plana Vitrectomy Port Sizes: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND AND OBJECTIVE

The uptake of small-gauge (SG; ie, 23-gauge [23-G], 25-gauge [25-G], and 27-gauge [27-G]) pars plana vitrectomy (PPV) has grown. We aim to investigate the advantages and disadvantages of various PPV port sizes in a meta-analysis of randomized controlled trials (RCTs).

MATERIALS AND METHODS

A systematic literature search was performed for RCTs comparing PPV port sizes for any indication. Weighted mean differences (WMDs) and risk ratios (RRs) were calculated, and meta-analysis was performed with random-effects models.

RESULTS

A total of 1,678 eyes from 22 RCTs were included. Risk-of-bias assessment found some concerns in 13 studies. Compared with 20-gauge PPV, there was no significant difference in the final or change in best-corrected visual acuity (BCVA; five studies analyzed each) relative to that of SG PPV. SG PPV was associated with a significantly greater incidence of hypotony (RR = 3.79; 95% confidence intervals [CI], 2.02 to 7.10; P < .0001; six studies) and choroidal detachment (RR = 5.65; 95% CI, 1.01 to 31.71; P = .05; three studies). Compared with 25-G PPV, there was no significant difference in BCVA at any time point with 23-G (two studies), and significantly more frequent port suturing was required with 23-G (RR = 0.46; 95% CI, 0.25 to 0.84; P = .01; two studies). Compared with 25-G PPV, 27-G was associated with a significantly better final BCVA (WMD = -0.06 logMAR; 95% CI, -0.11 to -0.01; P = .02; five studies) and a significantly lengthened surgery (WMD = 4.11 minutes; 95% CI, 0.18 to 8.05; P = .04; three studies).

CONCLUSIONS

There was no significant difference in visual or surgical outcomes following 20-gauge PPV relative to SG PPV (Grading of Recommendations, Assessment, Development, and Evaluation recommendation: low certainty), and there was an increased risk of postoperative complications with SG PPV (moderate certainty). Compared with 25-G PPV, 23-G required more frequent port suturing (moderate certainty), whereas 27-G may be associated with a better final BCVA but longer surgery (low and moderate certainty, respectively). [Ophthalmic Surg Lasers Imaging Retina. 2022;53:152-158.].

PREVALENCE AND RISK FACTORS OF ELLIPSOID ZONE DAMAGE AFTER PARS PLANA VITRECTOMY FOR IDIOPATHIC EPIRETINAL MEMBRANE

PURPOSE

To assess factors associated with external limiting membrane (ELM)/ellipsoid zone (EZ) damage after pars plana vitrectomy (PPV) for epiretinal membrane and evaluate ELM/EZ damage impact on functional and anatomical outcomes.

METHODS

Patients who underwent PPV with epiretinal membrane ± inner limiting membrane peeling were retrospectively analyzed. Best-corrected visual acuity and central macular thickness were longitudinally collected based on the available follow-up. Demographic data, clinical data, and surgical details were included in logistic regression models having ELM/EZ damage as a binary outcome.

RESULTS

Overall, 179 eyes (171 patients) were included; 93 had a 12-month follow-up. Thirty-four eyes (19%) had ELM/EZ damage after surgery; in nine eyes (5%), ELM/EZ damage persisted at 12 months. Phacoemulsification during PPV (odds ratio = 6.97; P = 0.007) and ELM/EZ damage before PPV (odds ratio = 6.91; P = 0.007) were risk factors for postoperative ELM/EZ disruption. Thicker outer nuclear layer (P = 0.002), thicker ectopic inner foveal layer (P < 0.001), and higher endoillumination power (P = 0.03) were associated with slower visual recovery. Inner limiting membrane peeling (P = 0.04) was associated with slower anatomical recovery.

CONCLUSION

Cataract extraction and outer retinal damage before PPV are associated with higher risk of photoreceptor damage postoperatively. The rate of visual improvement varies as a function of retinal layers' distortion before surgery; additional retinal manipulation slows restoration of the macular anatomy.

Lux study: Contribution of a three-dimensional, high dynamic range, ultra-high-definition heads-up visualization system to a significant delivered light intensity decrease during different types of ocular surgeries

OBJECTIVE

To explore the hypothesis that using a large, three-dimensional (3D), ultra-high-definition (4K), heads-up display (HUD) system in a real-life setting may be associated with a significant reduction in light intensity (LI) delivered during various types of eye surgery.

METHODS

Single center, post-learning curve observational study of 142 independent consecutive cases: 73 cataracts and 69 vitrectomies (VR). For each group, the only variable setting was the LI. The LI delivered by each source was calibrated in lumens (lm).

RESULTS

In the VR group, the delivered LI dramatically decreased from the 80% reference to 27.8%±13.2% (P<0.0001) (4.3 to 1.5lm). Among these surgeries, 91.3% needed 40% or less LI (2.3lm). The corneal transparency and quality of pupil dilation showed some correlation with the results. In the cataract group, the difference was even more spectacular, from 80% to 15%±11.3% (P<0.0001) (2.5 to 0.3lm). Among these surgeries, 80.8% required less than 20% LI (0.5lm). The surgical time, LI variations and type of cataract seemed to influence the results, down to 9.6%±5.4% (P<0.0001) (0.22lm) for nuclear cataracts, which represented 63% of the cataract sample.

CONCLUSION

The digital signal amplification with this HUD system allows comfortable posterior as well as anterior segment surgery despite the decrease in incident light, suggesting an unprecedented reduction in the risk of phototoxicity compared to conventional systems as well as a likely improvement in patient comfort.

Comparison of the effects of operating microscopes with light emitting diode and halogen light source on the eye: a rabbit study

PURPOSE

To evaluate the potential toxicity of operation microscopes with halogen and light emitting diode (LED) light source on the rabbit eyes.

MATERIALS AND METHODS

Thirty-two eyes of 16 male New Zealand pigmented rabbits were involved in the study. The rabbits were divided into two groups according to the type of light source applied. Only one eye of each rabbit was exposed to illumination light, unexposed fellow eyes served as the control group. Experimental groups included group 1 exposed to halogen light for 2 h and evaluated 1 day and 1 week after the illumination, group 2 exposed to LED light for two hours and evaluated 1 day and 1 week after the illumination. On the first and seventh days after exposing the light, we evaluated the rabbit corneas using in vivo confocal microscopy (IVCM). At the end of the seventh day, the Hematoxylin-eosin staining and TUNEL staining were performed to investigate the presence of apoptosis in the retina and retina pigment epithelium.

RESULTS

Early IVCM findings revealed corneal epithelial cell ovalization and indistinct intercellular borders in the halogen light group. We also observed more increase in the keratocyte density index (23.7% vs 14.1%, p = 0.001, respectively) and the Bowman reflectivity index (12.4% vs 4.1%, p = 0.001, respectively) at first day of the light exposure in halogen light group compared to LED light group. However, late IVCM indicated that these findings disappeared one week later. No apoptosis was observed in the corneal and retinal layers in early and late examination groups.

CONCLUSION

The present experimental study demonstrated that both halogen and LED lights, which were commonly used for microscopic eye surgery, had no sustained adverse effect on the cornea and retina of the rabbits; however, halogen light had a temporary adverse effect on corneal epithelium and stroma, which resolved within 1 week.

Comparing clinical outcomes of macular hole surgeries performed by trainee surgeons using a 3D heads-up display viewing system versus a standard operating microscope

PURPOSE

To compare the surgical outcomes of macular hole (MH) surgery performed by trainee surgeons using a three-dimensional heads-up display (3D HUD) versus a standard operating microscope (SOM).

MATERIALS AND METHODS

A retrospective review of all consecutive medical records patients operated on for MHs by a trainee surgeon between 2017 and 2020 using either 3D HUD or SOM was performed. Minimum hole diameter, maximum hole diameter, total surgical time, and MH closure rates were compared between the two groups. MH retinal detachments, traumatic MHs, and MHs for which inverted internal limiting membrane flaps were used were excluded from the study.

RESULTS

Trainee surgeons operated on 51 patients using 3D HUD and 63 patients using SOM. Age at presentation, intraocular pressure (IOP) at diagnosis, maximum hole diameter, minimum hole diameter, surgical time, duration between diagnosis and surgery were comparable between both groups. MH closure rate was significantly (p < 0.004) higher in the 3D HUD group (n = 44, 86.3%) than that of the SOM group (n = 38, 60.3%). There were no postoperative adverse events such as glaucoma or retinal detachment in either group. Other than the viewing technique, there were no significant variables associated with MH closure in the two groups.

CONCLUSION

Surgeries conducted by trainee surgeons using 3D HUD had higher MH closure rates than those using SOM.

Diffuse retinal pigment epithelium atrophy following pars plana vitrectomy for high myopic macular hole assisted by Brilliant Blue G: A case report

Purpose

To describe a case of diffuse retinal pigment epithelium (RPE) disturbance following 23-gauge pars plana vitrectomy (PPV) with the inverted internal limiting membrane (ILM) technique and Brilliant Blue staining for a high myopic macular hole (MH).

Observations

A 53-year-old pseudophakic high myopic female was referred to the Vitreoretinal Department with a diagnosis of a full thickness myopic MH of her right eye. Her initial visual acuity was 20/40 of her right eye and 20/20 in the left eye. She underwent routine PPV with inverted ILM flap assisted by repeated brilliant blue staining. Surgery was uneventful without any intraoperative complications. MH closure was obtained within the first days. Three weeks postoperatively, the patient reported a decline in visual acuity of her right eye. Upon examination, her visual acuity decreased to 20/400. Fundus examination showed diffuse pigmentary changes with mottling at the level of the RPE, which later progressed to severe diffuse atrophy, as confirmed by fundus autofluorescence (FAF). After 12 months, visual acuity remained 20/400 with widespread areas of atrophy.

Conclusions

Uncomplicated routinary PPV assisted with Brilliant Blue, can lead to unexplained atrophy of the RPE. Possible causes include light phototoxicity, dye toxicity or both.

Brilliant Blue G toxicity in macular hole surgeries: A report on combined phototoxicity and dye-induced macular damage

Purpose: Vitrectomy with brilliant blue G (BBG) assisted internal limiting membrane (ILM) peeling is the standard operational technique in macular hole surgeries. However, BBG dye, though considered safe and nontoxic, can also occasionally lead to macular toxicity. This study aims to describe the clinical features and characteristics of four eyes who developed macular toxicity after following surgery for macular hole repair.Methods: Retrospective review of four consecutive cases of macular toxicity after conventional BBG assisted ILM peeling. All the cases reviewed, their operative surgical notes were retrieved and analyzed. The ILM was stained twice during surgery with prolonged intraoperative surgical time.Results: All four cases had a prolonged surgical time and the ILM was stained twice during surgery in all cases. The area of macular toxicity was corresponding to the area of ILM peeling which had been exposed to repeated staining by BBG dye. By the end of one month, all four cases had foveal thinning along with choriocapillary atrophy. The mean BCVA was 20/80 before surgery and the final mean visual acuity was <20/800.Conclusion: This report highlights the occurrence of macular and choriocapillary atrophy due to prolonged focal endoillumination and the increased risk of toxicity with repeated dye staining.

3D Heads-Up Display vs. Standard Operating Microscope Vitrectomy for Rhegmatogenous Retinal Detachment

Purpose: To assess the efficacy and outcomes of 23-gauge vitreoretinal surgery for rhegmatogenous retinal detachment using a three-dimensional heads-up display (3D HUD) surgical platform as compared to a standard operating microscope (SOM) setting. Design: Retrospective cohort study. Participants: One hundred and forty consecutive eyes of 140 patients with primary retinal detachment. Methods: All eyes underwent 23-gauge pars plana vitrectomy for primary retinal detachment using either a 3D HUD (NGENUITY; Alcon Inc., Fort Worth, Texas, USA; n = 70 eyes) or a SOM setting (n = 70 eyes); in cases of significant cataract, additional phacoemulsification with intraocular lens (IOL) implantation was performed. Minimum follow-up was 2 months. Main Outcome Measures: Primary retinal reattachment rate, rate of proliferative vitreoretinopathy (PVR), best-corrected visual acuity (BCVA), and duration of surgery. Results: There were 70 eyes each in the 3D HUD and the SOM group. Both groups did not differ concerning age (p = 0.70), extent of retinal detachment (p = 0.07), number of retinal tears (p = 0.40), macular involvement (p = 0.99), and preoperative BCVA (p = 0.99). Postoperatively, 3D HUD and SOM were comparable concerning the primary retinal reattachment rate (88.6 vs. 94.3%; p = 0.37), the development of postoperative PVR (12.9% vs. 7.1%; p = 0.40) and final BCVA (0.26 ± 0.40 vs. 0.21 ± 0.38 logMAR; p = 0.99). Duration of surgery was significantly longer in the 3D HUD group (66.2 ± 16.5 vs. 61.2 ± 17.1 min; p = 0.04), an effect which however vanished after a "learning curve" of the first 35 eyes (p = 0.49). Conclusions: On par results to a conventional operating microscope can be achieved with a 3D HUD setting when performing 23-gauge vitreoretinal surgery for rhegmatogenous retinal detachment, including the primary retinal reattachment rate, the incidence of postoperative PVR and final BCVA. However, duration of surgery might initially be slightly longer with 3D HUD, suggesting the effect of a learning curve.

The User Experience on a 3-Dimensional Heads-Up Display for Vitreoretinal Surgery Across All Members of the Health Care Team: A Survey of Medical Students, Residents, Fellows, Attending Surgeons, Nurses, and Anesthesiologists

Purpose:

This work assesses the educational use of a 3-dimensional (3D) heads-up visualization system for vitreoretinal surgery.

Methods:

A cross-sectional survey was performed among 18 medical students, 18 residents, 7 VR fellows, 6 nurses, 4 anesthesiologists, and 3 surgeons on their experience with the Ngenuity 3D Visualization System (TrueVision and Alcon) compared with the standard microscope.

Results:

Most medical students (88%) reported better identification of surgical landmarks; 63% ranked the Ngenuity as their preferred method of learning (vs microscope or 2-dimensional display). Residents reported a superior understanding of anatomy (69%), an increased ability to ask questions (63%), and improved ergonomics (94%). Epiretinal membrane peel, internal limiting membrane peel, and core vitrectomy were most enhanced (69% to 77%) for residents. Fellows’ experience with trocar placement, vitrectomy, and oil/gas insertion was the same as before (67% to 100%), whereas endolaser and closing were worse (67% to 100%). Regarding autonomy, 83% of fellows reported no change, whereas 17% reported increased levels. Nurses were better able to track case progress (67%) and anticipate which tools were needed (50%). All anesthesiologists reported the same or worse engagement in cases, noting it was difficult to switch between the 3D screen and the anesthesia equipment. All surgeons reported a better awareness of trainees in the room and an improved ability to point out landmarks; 67% reported being more comfortable with resident and fellow autonomy.

Conclusions:

The Ngenuity is most helpful to students and residents. Integrating 3D displays into the surgical curriculum is beneficial, with care to ensure nurse and anesthesiologist satisfaction.

Management of Full-Thickness Macular Hole in A Genetically Confirmed Case with Usher Syndrome

INTRODUCTION

Full-thickness macular hole (FTMH) formation is rarely seen in patients with retinitis pigmentosa (RP) and can have an adverse impact on their residual visual function. The underlying mechanisms are unknown, and clinical experience is limited regarding surgical outcomes. Here, we describe the surgical management of FTMH in a young patient with genetically confirmed Usher syndrome, the most common form of syndromic RP.

CASE REPORT

A 28-year-old woman presented with blurred vision in her right eye (RE). She had a history of RP and bilateral hearing impairment since childhood. Fundoscopy and spectral-domain optical coherence tomography revealed a FTMH in the RE along with typical RP features bilaterally. After pars plana vitrectomy (PPV) with internal limiting membrane peel and gas tamponade, the FTMH closed. Six months after PPV the patient underwent cataract surgery in the affected eye, and the visual acuity remained stable compared to baseline. The clinical diagnosis of Usher syndrome was genetically confirmed by whole exome sequencing (WES), which revealed the presence of two pathogenic nucleotide variants in trans (compound heterozygosity) in the gene USH2A.

CONCLUSION

We report a rare case of successful closure of a FTMH in a patient with Usher syndrome. Surgical treatment of FTMH can help preserve the central vision in RP patients, whose peripheral vision is severely affected.

Comparison of microscopic illumination between a three-dimensional heads-up system and eyepiece in cataract surgery

INTRODUCTION

The ability to reduce illumination levels is generally accepted as one of the main benefits of a three-dimensional heads-up system (3D system: Ngenuity®; Alcon, CA, USA). Some studies have focused on illumination reduction in vitreoretinal procedures; however, information regarding illumination reduction in cataract surgery has not been published.

PURPOSE

This study aimed to compare the illumination of the operational field with a 3D system and a standard microscope eyepiece during cataract surgery.

SUBJECT AND METHODS

We retrospectively evaluated 91 eyes of 84 consecutive patients who were undergoing cataract surgery at our hospital. We used the 3D system and the eyepiece on alternative days. We determined the minimum light intensity required for safe surgery using the foot switch of the microscope (OMS800; Topcon, Tokyo, Japan). Illuminance on the ocular surface and the minimum illuminance required for the operation were calculated from the minimum light intensity.

RESULTS

The 3D system was used in 45 eyes (3D group), and the eyepiece was used in 46 eyes (eyepiece group). The values of minimum illuminance in the 3D group were significantly lower than those in the eyepiece group (3D: 5500 ± 2000 lux, eyepiece: 11,900 ± 1800 lux; p < 0.001*). In addition, the illuminance of the operational field was reduced by 60.4% on average using the 3D system.

CONCLUSION

With real-time digital processing and automated brightness control, the 3D system reduced ocular surface illumination by 50% or more. Hence, the 3D system may contribute to reducing the risk of retinal phototoxicity and patient photophobia.

Comparing Heads-Up versus Binocular Microscope Visualization Systems in Anterior and Posterior Segment Surgeries: A Retrospective Study

BACKGROUND

Three-dimensional (3D) visualization systems, also known as heads-up systems, are now available for eye surgery and as with every new device there is need for a specific evaluation.

OBJECTIVES

The aim of this study was to compare the efficiency, surgical comfort, and safety of a 3D visualization system to a standard binocular microscope (BM) in routine ophthalmologic procedures.

METHOD

After a 4-week training period, a 3D visualization system (Ngenuity, Alcon®) available in one of the Robert Debré Hospital Ophthalmology Departments' operating rooms was compared to a standard BM (OPMI LUMIRA 700, Zeiss®), in the process of a call for new device evaluation. From December 2017 to March 2018, 5 surgeons and their respective residents were asked to fill in a questionnaire for all procedures. Before the surgery, the surgeon recorded: (i) the type of surgery (cataract [PK], retinal detachment [RD], epiretinal membrane peeling [ERM], macular hole, vitreous haemorrhage [VH]), (ii) the type of visualization system chosen (3D or BM), and (iii) the estimated surgical risk (low, intermediate, or high grade). At the end of the procedure, the primary surgeon recorded the remaining parameters, including: (i) surgery duration, (ii) intraoperative complications, (iii) percentage of endoillumination for posterior segment surgeries, (iv) status of the operator (senior or resident) and operator switch if necessary (senior only, resident only, or resident with help of the senior), and rated: (i) the visual comfort (low, normal, excellent), (ii) the operative fluency (low, normal, excellent), (iii) backaches (none, low, moderate, important), and (iv) headaches (range from 0 to 10). Age and sex were collected retrospectively. The procedures performed with 3D and BM were subsequently compared using univariate (χ2, Fisher, Wilcoxon) and multivariate analysis (generalized linear model), allowing us to identify parameters independently associated with PK surgery duration.

RESULTS

A total of 102 valid questionnaires, relative to 73 PK and 29 vitreoretinal procedures, respectively, were analysed. As regards PK (3D, n = 25 vs. BM, n = 48), the mean age, sex ratio, surgical risk, intraoperative complications (1/25 vs. 4/48), visual comfort, backaches, and headaches were similar between the two systems. The use of 3D allowed faster PK surgeries (16.44 ± 4.36 vs. 21.44 ± 7.50 min; p = 0.007) and slightly enhanced the operative fluency. In vitreoretinal surgeries (3D, n = 14 vs. BM, n = 15), no obvious differences between the two visualization systems were observed, although the use of the 3D system was found to slightly decrease the operative fluency. Parameters independently associated with PK surgery duration were 3D visualization (β = -4.4 ± 1.4; p = 0.002), high preoperative surgical risk (β = 6.2 ± 2.4; p = 0.012), intraoperative complications (β = 8.7 ± 2.6; p = 0.001), and surgeon status (β = -4.4 ± 1.3; p = 0.001) in univariate and multivariate analysis.

CONCLUSIONS

3D visualization can be safely used in routine practice. It slightly improves the operative fluency, allowing faster PK surgery.

Phototoxic maculopathy due to extreme usage of infrared illuminator-assembled night-vision handheld scope

Night-vision handheld scopes are of wide use in military operations at dark conditions. In some cases in the battlefield, as in our case report, if there is no light coming from any source (neither from Moon nor from Stars), infrared light-emitting diode illumination can be coupled with night-vision goggles. Reflected illumination from the target is mostly blue filtered through the night-vision goggles objective lens. Retinal damage induced by unfiltered blue light and visible light has been previously reported. We described a phototoxic maculopathy induced by night-vision handheld scope assembled with infrared light-emitting diode illuminator in two soldiers who are on duty at nights for nearly two-thirds of the last year. The phototoxic maculopathy can represent with typical optical coherence tomography findings such as intraretinal hyperreflective accumulation particularly located on the surface of outer retinal segments defect or presumably in the vicinity of the light passageway. Here, we presented a unique factor causing phototoxic maculopathy.

Learning curve of three-dimensional heads-up vitreoretinal surgery for treating macular holes: a prospective study

PURPOSES

To compare surgeons' opinions regarding idiopathic full-thickness macular hole (MH) surgery by using traditional microscopy and three-dimensional (3-D) visualization system. To analyze the required time for pars plana vitrectomy (PPV) and for internal limiting membrane (ILM) rhexis by using both visualization methods. To evaluate anatomical surgical results.

METHODS

Four surgeons (surgeon 1, fellows 1, 2, 3) performed the total of 40 surgeries for treating MHs. Each one performed 10 surgeries (5 with traditional microscopy and 5 with 3-D visualization). The completion time for PPV and ILM rhexis was determined by using both methods. Ergonomics, educational value, image sharpness, depth perception, field of view and technical skills were analyzed through answering a questionnaire.

RESULTS

Forty patients were included in the study. The MH size for surgeon 1, fellows 1, 2 and 3 groups, individually, ranged from 237 to 602 μm; 228 to 590 μm, 271 to 611 μm and 289 to 600 μm, respectively. In the 3-D and in the traditional microscopy subgroups (which includes all 4 physicians on the use of one or the other method), the MH size ranged from 228 to 602 μm and 237 to 611 μm, respectively. Comparisons between the average time for full PPV and ILM rhexis by using the two methods were non-significant, neither in each individual case of 3-D surgery for each surgeon. Surgeon 1 had always been faster than his fellows. Depth perception was rated as similar for both methods. Field of view and educational values were rated as superior when using the 3-D system. Image resolution and ergonomics were rated as superior when using traditional microscopy. Technical skills strongly tended toward 'superiority' when using traditional microscopy. Thirty-six (90%) full-thickness MHs were successfully closed with one surgery.

CONCLUSION

The 3-D system for MH surgery had a short learning curve and was a refined educational tool, when used with reduced illumination and precise focus. Concerning MH surgery, heads-up method was similar to traditional microscopy regarding length of time and anatomical surgical results. Heads-up surgery may become a new pattern for ophthalmic surgery as ongoing improvements are applied.

An experimental and clinical study on the initial experiences of Brazilian vitreoretinal surgeons with heads-up surgery

PURPOSE

To evaluate the initial experiences of several vitreoretinal surgeons in Brazil, both experienced and beginners, with a three-dimensional (3D) system, and to report the advantages and disadvantages of this technology. We also report surgical manipulations performed using the heads-up method in porcine eyes. For full-thickness idiopathic macular holes (MHs), we analyzed the times required for pars plana vitrectomy (PPV) and internal limiting membrane (ILM) rhexis by using traditional microscopy and 3D system, and to evaluate anatomical surgical results.

METHODS

During experimental vitreoretinal surgery on porcine eyes, two retinal surgeons applied the heads-up method. In clinical surgery, 14 retinal surgeons performed almost all types of vitreoretinal surgeries in association with facectomy, Ahmed glaucoma valve implant, or minimally invasive glaucoma surgery using an iStent®. The Ngenuity® 3D Visualization System was digitally integrated with intraoperative optical coherence tomography, the Verion™ Image-Guided System, and an endoscope (with a modified GoPro® camera). To compare the 3D system with traditional microscopy, ergonomics, educational value, image sharpness, depth perception, field of view, advantages and disadvantages, and technical feasibility were assessed using a questionnaire. One year later, the 14 surgeons answered the same questionnaire again, in order to assess whether they became more comfortable or not with 3D. For treating MHs, four surgeons (surgeon 1, fellows 1, 2, 3) performed the total of 40 surgeries. Each one performed 10 surgeries (5 with traditional microscopy and 5 with 3D visualization). The completion time for PPV and ILM rhexis were determined by using both methods.

RESULTS

In porcine eyes, disabling the color channels allowed better visualization of the ILM, either with Brilliant Blue G (BBG), indocyanine green chorioangiography (ICG), or açai dye; transillumination through the sclera was also better without a color channel, but visualization of the peripheral vitreous was better with a blue channel. Regarding clinical experience, the questionnaire responses showed that the respondents generally favored the heads-up method compared with traditional microscopy (p < 0.05); however, despite a slightly higher average score, the 3D system was not statistically significantly preferred in terms of technical feasibility (p = 0.1814). Answering again the same questionnaire 1 year later, the 14 surgeons felt more comfortable with 3D (p < 0.05). The type of surgery benefitting most from the 3D system was peeling of the ILM or epiretinal membrane (p < 0.001), and that receiving the least benefit was anterior segment surgery (p < 0.001). In addition, surgeons did not report benefits of color channels, preferring to disable it (p < 0.001). Comparisons between the average time for full PPV and ILM rhexis by using the two methods were non-significant, neither in each individual case of 3D surgery for each surgeon. Surgeon 1 had always been faster than his fellows. Thirty-six (90%) full-thickness MHs were successfully closed with one surgery.

CONCLUSIONS

The 3D system was preferred to traditional microscopy. The 3D system was especially helpful for certain specific types of surgeries and served as an educational tool, having reduced illumination and allowing precise focusing. Concerning MH surgery, heads-up method was similar to traditional microscopy regarding length of time and anatomical surgical results. As a digital platform, it will be amenable to constant upgrades and may ultimately become the new standard for ophthalmic surgery.

The Preliminary Experiences with Three-Dimensional Heads-Up Display Viewing System for Vitreoretinal Surgery under Various Status

Statement: The current article has not been published elsewhere and has not been submitted simultaneously for publication elsewhere.

PURPOSE

To investigate the preliminary use of three-dimensional (3D) heads-up display (HUD) viewing system for vitreoretinal surgery under various status.

MATERIALS AND METHODS

Nonrandomized case-control study. Consecutive cases to have vitreoretinal surgery under various status were prospectively recruited. Twenty-five-gauge vitrectomy platform and 3D viewing system were used. Main outcomes included: luminous emittance (lux) of endoillumination pipe, surgical duration, the surgeon and residents' preference and ergonomics. Consecutive patients to have vitreoretinal surgery with the conventional viewing system were recruited as control group following the same inclusion and exclusion criteria and underwent surgeries by the same surgeon with the same microscope and vitrectomy platform.

RESULTS

Thirty-one patients (31 eyes; Group Study) and twenty-eight patients (28 eyes; Group Control) were included; without significantly statistical difference in terms of age, gender, main diagnosis, surgical duration, and difficulty rating between both groups (all P > 0.05). Lower endoillumination intensity was needed in Group Study than that in Group Control (10% vs. 35%; 598.7 ± 5.4 vs. 1913.0 ± 12.9 lux, P < 0.001). The surgeon and residents expressed overwhelming preference with the 3D system in both groups. Improved ergonomic was rated in Group Study (4.4 ± 0.8 vs. 3.2 ± 1.0, P < 0.001). Some intraoperative difficulties and discomforts appeared to the surgeon and assistants when using the 3D viewing system.

CONCLUSION

Vitreoretinal surgery under various status can be well finished with the HUD platform by novice at the system. Main benefits included lower endoillumination intensity, enhanced users' preference, and improved ergonomics. Some further refinements of the system are expected.

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.

MINIMAL ENDOILLUMINATION LEVELS AND DISPLAY LUMINOUS EMITTANCE DURING THREE-DIMENSIONAL HEADS-UP VITREORETINAL SURGERY

PURPOSE

To determine minimal endoillumination levels required to perform 3-dimensional heads-up vitreoretinal surgery and to correlate endoillumination levels used for measurements of heads-up display (HUD) luminous emittance.

METHODS

Prospective, observational surgical case series of 10 patients undergoing vitreoretinal surgery. Endoillumination levels were set to 40% of maximum output and were decreased at set intervals until the illumination level was 0%. Corresponding luminous emittance (lux) of the HUD was measured 40 cm from the display using a luxmeter (Dr. Meter, Model #LX1010BS).

RESULTS

In 9 of 10 cases, the surgeon felt that they could operate comfortably at an endoillumination level of 10% of maximum output with corresponding HUD emittance of 14.3 ± 9.5 lux. In the remaining case, the surgeon felt comfortable at a 3% endoillumination level with corresponding HUD emittance of 15 lux. Below this threshold, subjective image dimness and digital noise limited visibility. Endoillumination levels were correlated with luminous emittance from the 3-dimensional HUD (P < 0.01). The average coefficient of variation of HUD luminance was 0.546. There were no intraoperative complications.

CONCLUSION

With real-time digital processing and automated brightness control, 3-dimensional HUD platforms may allow for reduced intraoperative endoillumination levels and a theoretically reduced risk of retinal phototoxicity during vitreoretinal surgery.

Review of Small Gauge Vitrectomy: Progress and Innovations

Purpose. To summarise the surgical advances and evolution of small gauge vitrectomy and discuss its principles and application in modern vitreoretinal surgery. The advent of microincisional vitrectomy systems (MIVS) has created a paradigm shift away from twenty-gauge vitrectomy systems, which have been the gold standard in the surgical management of vitreoretinal diseases for over thirty years. Advances in biomedical engineering and surgical techniques have overcome the technical hurdles of shifting to smaller gauge instrumentation and sutureless surgery, improving surgical capabilities and expanding the indications for MIVS.

Endoilluminator phototoxic maculopathy associated with combined ICG-assisted epiretinal membrane and internal limiting membrane peeling

Phototoxic maculopathy caused by endoillumination during macular surgery is uncommon. Previously identified risk factors have included intensity of the light source, proximity to the retinal surface, and length of exposure. In the era of indocyanine green (ICG)-assisted internal limiting membrane (ILM) peeling, the use of ICG, and the technique of ILM peeling may both contribute to subsequent phototoxic maculopathy. We present cases of routine chromovitrectomy who developed phototoxic maculopathy in the precise discrete distribution of the ILM rhexes, and discuss potential mechanisms and implications.

Retinal endoilluminator toxicity of xenon and light-emitting diode (LED) light source: rabbit model

OBJECTIVE

This study evaluates retinal toxicity due to endoillumination with the light-emitting diode (LED) light source in comparison to endoillumination with xenon light source.

MATERIAL AND METHODS

Twenty-five eyes of 14 New Zealand pigmented rabbits were used in the study. The LED light (Omesis Medical Systems, Turkey) group was composed of 7 right eyes, while the other 7 right eyes constituted the xenon group (420 nm filter, 357mW/cm(2)) (Bright Star; DORC, Zuidland, Netherlands). Eleven untreated left eyes composed the control group. Twenty gauge pars plana incision 1.5 mm behind the limbus was performed in the right eyes. Twenty gauge bullet type fiberoptic endoilluminator was inserted into the eye from the incision without any pars plana vitrectomy. Fiberoptic endoilluminator was placed in such a way that it was directed toward visual streak of the rabbit retina with a 5 mm distance to retinal surface. Endoillumination was then applied for 20 min with a maximum light intensity for LED and xenon light. In left control eyes, no surgical procedure and no endoillumination were performed. One week after the endoillumination procedure, both eyes of the rabbits were enucleated following electroretinography. Sections stained with hematoxylin and eosin to evaluate morphologic changes. Retina tissues were assessed by active caspase-3 staining.

RESULTS

There was no difference in the shape of the waveforms recorded in the eyes endoilluminated with LED light and xenon light sources compared to control eyes both before and after endoillumination application (p > 0.05). Microscopic evaluation of the retinas with hematoxylin and eosin staining demonstrated that all study groups have normal histologic properties similar to control group. No apoptosis positive cells were found within all sections in all groups.

CONCLUSIONS

When the LED light source is used with maximum power and limited duration for endoillumination in rabbit eyes it does not produce phototoxic effects that may be detectable by electrophysiology and histology similar to xenon light.

Clinical evaluation and feasibility of changing intraoperative visibility with a novel viewing filter system for human eye

PURPOSE

The study was conducted to develop a new viewing system as a clinical prototype that enables visibility during surgery.

METHODS

The system was composed of several filters attached to the microscope. This nonrandomized, retrospective, observational case series study involved 33 eyes from 32 patients who presented with various diseases and underwent surgery. The authors evaluated the changes in visualization focusing on controlling intraoperative visibility under air infusion and enhancing Brilliant Blue G staining focusing a sharp-cut filter Y (SCY). Visibility was compared under various surgical conditions, including cataract surgery, both with and without this system. Quantitative analysis of changes in intraoperative reflection including halation under air infusion and Brilliant Blue G intensity was carried out using the International Commission on Illumination 1976 (L*, a*, b*) color space method.

RESULTS

A SCY reduced the reflection and halation by a maximum of 69.6%, when compared with use of no filter under air infusion (P < 0.01). The color difference between Brilliant Blue G-stained and nonstained areas was improved by 127.8% relative to values with no filter and using SCY (P < 0.01) in macular hole cases. Furthermore, in cataract surgery with corneal opacity, improvement of visibility was observed by SCY insertion.

CONCLUSION

The system improved intraoperative visibility under air infusion and the Brilliant Blue G staining intensity by use of SCY during vitrectomy.

Unanticipated vision loss after pars plana vitrectomy

Although advances in vitreoretinal surgical techniques and technology have helped to minimize the risks associated with surgical manipulation of the retina, retinal pigment epithelium, and optic nerve, unanticipated or unexplained visual loss still occurs. We review causes of vision loss encountered after pars plana vitrectomy, including retinal toxicities, vascular events, and optic neuropathies, and we suggest strategies to limit or prevent them.

Development and preclinical evaluation of a new viewing filter system to control reflection and enhance dye staining during vitrectomy

PURPOSE

We developed a new artificial image enhancement system and evaluated its usefulness in controlling intraoperative reflection and enhancing of Brilliant Blue G (BBG) staining.

METHODS

The system was composed of three kinds of filters (a polarizing filter, a blue-enhancing filter, and a sharp-cut filter Y) and attached to the inferior surface of the operating microscope. Twenty-seven post-mortem extracted porcine eyes were used for a series of examinations. We performed surgery using the 23G-vitrectomy system with a halogen light and xenon lights and compared the reduction of intraoperative reflection under air condition and visibility and BBG contrast with and without this system. The evaluation of images was calculated in CIE 1976 (L*, a*, b*) color space (CIELAB) carried out by ImageJ software. The transmission of each filter and absorbance of BBG was measured by a spectrophotometer. We measured spectral irradiance at each wavelength about each filter from each light source with a spectroradiometer.

RESULTS

Under both light sources, intraoperative reflection was controlled using a polarizing (PL) filter or combination of filters under air condition. Evaluation of the value of L* within the cutter surface was changed by 37.8 % under the halogen light, and 61.6 % (averaged) under the xenon light with inserted filters versus no filter. The BBG intensity difference was obtained with sharp-cut Y filter under both light source and PL with blue enhancing filter under the halogen light using each L*, a*, b* parameter with statistically significant (p < 0.01, 0.05). However, there was a relative decrease in the observation illuminance when the filter inserted according to the attenuation total spectral irradiance.

CONCLUSIONS

This system can reduce intraoperative reflections under the air condition and obtain an excellent BBG staining intensity induced by various light sources.

Thermal deformation of chandelier endoillumination probes exposed to uveal tissue and blood

PURPOSE

The purpose of this study was to evaluate the characteristics and thermal properties of a chandelier endoillumination probe under conditions that may induce thermal damage.

METHODS

Experimental evaluation of a surgical ophthalmic instrument under ex vivo conditions.

RESULTS

A 27-gauge dual-tip chandelier endoillumination probe was exposed to air, saline, porcine uveal tissue, and human blood using a Xenon light source at 100% intensity. No alteration of probe tip morphology was observed in air or saline at 10-minute exposure. After exposure to uveal tissue and blood, thermal melting of the probe tip was noted at 10 minutes. Beam focus and intensity were observed to diminish in the probe tips that underwent thermal melting. A thermal imaging device was used to demonstrate increased thermal intensity from the probe tip that had been covered with uveal tissue compared with a control tip in air.

CONCLUSION

Thermal melting of a chandelier fiber probe has been reported only once previously in the literature after exposure to porcine Tenon capsular tissue. We report two separate conditions that may induce thermal damage to a fiber optic probe including encapsulation of uveal tissue at the probe tip and exposure to blood. Vitreoretinal surgeons should be aware of this potential complication.

Intraoperative spectral domain optical coherence tomography for vitreoretinal surgery

We demonstrate in vivo human retinal imaging using an intraoperative microscope-mounted optical coherence tomography system (MMOCT). Our optomechanical design adapts an Oculus Binocular Indirect Ophthalmo Microscope (BIOM3), suspended from a Leica ophthalmic surgical microscope, with spectral domain optical coherence tomography (SD-OCT) scanning and relay optics. The MMOCT enables wide-field noncontact real-time cross-sectional imaging of retinal structure, allowing for SD-OCT augmented intrasurgical microscopy for intraocular visualization. We experimentally quantify the axial and lateral resolution of the MMOCT and demonstrate fundus imaging at a 20Hz frame rate.

Operating microscope light-induced phototoxic maculopathy after transscleral sutured posterior chamber intraocular lens implantation

PURPOSE

The purpose of this study is to report the features of operating microscope light-induced retinal phototoxic maculopathy after transscleral sutured posterior chamber intraocular lens (TSS PC-IOL) implantation.

METHODS

The charts of 118 patients who underwent TSS PC-IOL implantation surgery at Chonbuk National University Hospital (Jeonju, Korea) between March 1999 and February 2008 were retrospectively reviewed. Fourteen patients underwent combined 3-port pars plana vitrectomy and TSS PC-IOL implantation (vitrectomy group), and 104 patients underwent TSS PC-IOL implantation only (nonvitrectomy group). All surgeries were performed under the same coaxial illuminated microscope. All diagnoses were confirmed through careful fundus examination and fluorescein angiography (FA).

RESULTS

Diagnoses of retinal phototoxic maculopathy were established in 10 (8.47%) of 118 TSS PC-IOL implantation cases. Phototoxic maculopathy occurred more frequently in the vitrectomy group than in the nonvitrectomy group (6/14 versus 4/104, respectively; P < 0.001, chi-square = 24.21). Affected patients reported decreased vision and were found to have coarse alterations of the retinal pigment epithelium (RPE). In 5 of the phototoxic maculopathy cases (50%), the visual acuity was 20/200 or worse.

CONCLUSION

Operating microscope light-induced retinal phototoxic maculopathy can occur more frequently after TSS PC-IOL implantation than after casual cataract surgery, especially when TSS PC-IOL is combined with vitrectomy surgery. Surgeons should take precautions to prevent retinal phototoxicity after TSS PC-IOL implantation and vitrectomy.