Dr. NAREN SHETTY

Dr. AISHWARYA, Dr.P. ROHITHA NAYAK, Dr. LUCI KAWERI

Semi Final

Abstract

Purpose:To compare ease of visualization and surgeon comfort while performing phaco using NGENUITY®system vs standard operating microscope(SOM)Methods:Prospective,randomized study with active control group.Interimanalysis of 123 eyes,64 operated using SOM, 69 using NGENUITY®3D Visualization System by 5 surgeons.Included pts between 40-70,nuclear sclerosis grade 2 or more.Post surgery,Surgeon’s Comfort Score filled.Corneal edema,cells and flare,vision compared.Results:Brightness and illumination of surgical field of SOM more compared to NGENUITY for 5 surgeons (p<0.0001).Comfort with brightness better with NGENUITY® compared to SOM (p<0.05).Neck comfort better using NGENUITY®.Ease of visualization of steps of surgery better using NGENUITY, but statistically insignificant.Corneal edema,cells comparable.Conclusion:NGENUITY system works well with lesser illumination providing comfort to surgeon.Ease of visualization better with more distance between surgeon and patient with NGENUITY®

Full Text  

COMFORTABLE AND SAFE 3D HEADS UP VISUALIZATION SOLUTION FOR PHACOEMULSIFICATION

Purpose

To compare ease of visualization and comfort of the surgeon during phacoemulsification surgery using NGENUITY® 3D (NG) visualization system and standard operating microscope (SOM).

Design:

A randomized, single-blind, prospective, single center study.

Introduction:

Cataract is the leading cause of blindness accounting for 66.2% of blindness cases in India, as per the National Blindness and Visual Impairment Survey India 2015-2019.1 Phacoemulsification is one of the safest and preferred method of cataract surgery, performed since 1967.2 Optimal visualization of the anterior capsule, nucleus, cortex, and posterior capsule is one of the primary requirements of phacoemulsification.3 Surgical visualization using optical microscopy has been the standard for intraoperative surgical viewing since more than five decades.

Although significant advances have been made in the optical quality, illumination and depth of field, several limitations still persist. These include dependence on oculars, low performance under high-magnification, use of dyes to highlight certain structures, ergonomics issues for surgeons, photo toxicity due to excessive light exposure, inability to display vitrectomy machine setting parameters through the oculars, and limited illumination of the visualization field in terms of brightness and contrast.

4,5 Heads-up three-dimensional (3D) visualization systems enable surgeons to operate independent of the eyepieces of the standard operating microscope (SOM) replacing them with high-resolution visualization systems thereby improving the ergonomics. 3D high dynamic range technology and improved images under high-magnification allows lighting to be optimized across a wide range of brightness and darkness and permitting precision in the movement of instruments and manipulation of tissue within vitreous cavity. Additionally, digital video functionality has undergone rapid advancements in frame rate, pixel count and resolution, dynamic range, and latency over the past few years.

In NG, the captured images are processed using a 3D image processor and displayed on a 3D 4K OLED 55-inch display, which can then be viewed by the surgeon through a pair of passive, circular, polarized 3D glasses.5-8 Compared to SOM, NG platform results in up to 48% increased magnification, 5 times better depth of field, and up to 42% finer depth resolution (stereopsis) at the highest system magnification, 30% open aperture setting, and a viewing distance of 1.2 meters.

Till date, no study has focussed on the benefits of a heads-up 3D system such as Ngenuity (NG) in terms of ease of visualization and comfort for the surgeon in the heads-up position. Thus, we conducted a prospective study to evaluate the above factors during phacoemulsification surgery using NG versus SOM (Zeiss OPMI Lumera I Operating microscope i060). A novel surgeon comfort score questionnaire designed in-house was completed by five senior cataract surgeons at the end of each surgical session to assess the ease of visualization and comfort enhancing the robustness of the data.

Methods:

Patients undergoing phacoemulsification surgeries by 1 of the 5 surgeons were randomly assigned to two groups based on the visualization modality used—NG and SOM. A total of five surgeons operated on 224 patients having cataracts. Four surgeons operated on 17 patients each, with SIMC in the NG group and the SOM group; fifth surgeon performed 19 surgeries on SIMC patients in each of the NG and SOM groups. In total, 174 SIMC surgeries were performed for group NG and SOM, respectively, by the five surgeons. Additionally, each surgeon also operated on 10 patients having MC, 5 in NG group and 5 in the SOM group; with the overall total of 224 patients. Ease of visualization and comfort of the surgeon using different visualization systems was assessed using a 37-parameter surgeon comfort score questionnaire developed in-house.

Statistical Analysis

All randomized subjects were included in the effectiveness analyses. The statistical analysis was carried out using available data based on pooled data of all surgeons. Data was listed and descriptive analysis were provided by NG visualization system and SOM. Categorical data was summarized by means of absolute and relative frequencies (counts and percentage), quantitative data by means of the number of observations, mean, median, SD, and range (min, max).

The 95% confidence interval was provided as appropriate. Effectiveness analyses included two-sided statistical testing for the primary endpoint (the ease of visualisation of the surgeon while doing phacoemulsification procedure) using Kruskal Wallis test to compare two viewing modalities. Some of the parameters were analysed using an independent t-test or Mann Whitney u test. Categorical variables between the two viewing modalities were compared using Chi-square (2)/Fisher’s exact test of treatment group differences. Correlation coefficient was calculated using Spearman’s rank correlation coefficient. Serious/adverse events were summarized.

Results:

A total of 224 phacoemulsification with intra ocular lens (IOL) implantation was performed in senile immature cataract (SIMC, n=174) and mature cataract patients (MC, n=50) using NG and SOM as the visualization system. The intraoperative ease of visualization score of the surgeon while performing phacoemulsification was comparable between NG and SOM groups (4.92–5.00). The mean score for difficulty in using the 3D spectacles and fogging of the surgeon’s glass spectacles was in the range of 4.97–5.00 and 2.93–3.00, respectively.

Hand eye coordination score was similar in the NG and SOM groups (4.97–5.00). Neck discomfort after the surgery was significantly high in all groups, with a comparatively lower discomfort in the NG group (score: 1.04 vs 1.56). The Spearman rank correlation coefficient (r) between illumination of the OT room and surgical field revealed a weak negative correlation for most of the patients in the NG group, and a positive correlation for patients in the SOM group. Surgeons needed lower illumination for surgery while working on NG compared to the SOM and surgeon comfort with the illumination was also higher with NG system. No correlation was obtained between brightness of the surgical field and comfort with the brightness of the surgical field.

Discussion:

This study was conducted to evaluate the ease of visualization of the surgeon using a 3D heads-up display system (Alcon Vision LLC, Fort Worth, TX, USA). In this study, we found the intraoperative ease of visualization of the surgeon to be similar using NG or SOM visualization system. However, the NG system required very low illumination of the surgical field as compared to SOM, thus reducing the risk of photoxicity to the patients.

Better ergonomics for the surgeon, superior visualization of the surgical field in low illumination, reduced phototoxicity for patients, good anatomic and visual outcomes, and easy learning curve are some of the benefits of the 3D system. The earliest report on the use of a 3D visualization system in cataract surgery was in 2010 by Weinstock et al reporting excellent outcomes using both 3D system and conventional binocular microscope9. The same group in 2019 reported comparable complication rate and surgical time between NG visualization system and SOM.10 The safety and usefulness of NG visualization system for cataract phacoemulsification and IOL implantation was reported recently.

11 The 3D visualization system provides real-time intraoperative images of the surgical field with a short image latency. The latency documented for NGENUITY is in the range of 80 milliseconds between intraocular maneuvers and image displayed on screen compared to conventional microscope. Several studies have reported the latency to be insignificant for ophthalmic surgeries when compared with the conventional microscope.12, 13 The almost similar ease of visualization score using the NG and SOM system was in corroboration with these study findings.

High scoring of the difficulty in using the 3D spectacle revealed the relative ease the surgeons experienced while donning the 3D spectacle. Maintaining a clear operating field is one of the key elements while performing any surgical procedure and fogging of the surgeon’s glass spectacles can cause an obstacle in achieving this objective. Another significant advantage of the 3D visualization system is the decreased amount of light required to provide the enhanced visualization to the surgeon. Hamasaki et al. reported the successful use of NG system for strabismus surgery performed with only the room’s ambient light and without the microscope’s light source. 14 Illumination reduction of the surgical field reduces the risk of renal photo toxicity for patients during the surgery.

15 A lower illumination was used for the NG system as compared to the SOM system enabling the surgery to be performed with a lower risk of photo toxicity in the former case. 16 Likewise, the brightness of the surgical field was more for the SOM system than NG and surgeons reported more comfort using the NG system based on the comfort with brightness score. However, no correlation was obtained between brightness of the surgical field and comfort with the brightness of the surgical field. Most of the studies reported a comparable or lower rate of surgery duration using the NG system

Conclusions:

Overall, ease of visualization of the surgeon using the NG system and SOM system were comparable. Most of the parameters were similar for the NG and SOM system; however, a relatively lower illumination of surgical field was required in case of the NG system. Innovations in the 3D visualization system, such as the NG system have automated cataract surgery, and may result in a transition from the SOM system to the heads up display system in the future.

References

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