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

Improved brilliant blue G staining of the internal limiting membrane with sharp cut filters of a novel viewing filter system

PURPOSE

We developed a new artificial image enhancement system aimed at intraoperative visibility improvement as a clinical prototype. We examined each optical characteristic and change in intraoperative visibility using brilliant blue G (BBG) staining with various sharp cut filters (SCFs).

METHOD

This was a retrospective and observational study. The system was composed of several filters attached to the operating microscope. Six eyes from 6 patients who presented with macular hole and underwent surgery using this system were studied. As a clinical examination, the intraoperative visibility of BBG staining intensities was compared for 4 kinds of SCFs during vitrectomy. Quantitative evaluation was calculated using the International Commission on Illumination 1976 (L*, a*, b*) color space (CIELAB) method. Furthermore, we evaluated each optical characteristic of 4 types of SCFs using extracted porcine eyes and a spectroradiometer as a clinical simulation.

RESULTS

Suitable filter selection was possible for this system. The observed color tone and spectral irradiance changes with SCF insertion changed dynamically. In macular hole cases, the color intensities between BBG-stained and nonstained areas were improved using SCF-455 and SCF-520, which was statistically significant (p < 0.05) by CIELAB.

CONCLUSION

The system improved BBG staining intensity with the use of selective SCFs.

The price for reduced light toxicity: Do endoilluminator spectral filters decrease color contrast during Brilliant Blue G-assisted chromovitrectomy?

BACKGROUND

Vitreoretinal surgeons have been slow to adopt the use of spectral filters for endoillumination to reduce retinal light toxicity. This study shows that spectral filters can be used without a loss in color contrast during brilliant blue G chromovitrectomy.

METHODS

To evaluate the influence of intra operative spectral light filters on perceivable contrast during Brilliant Blue G chromovitrectomy, a prospective, observational clinical study was carried out on 59 consecutive Brilliant Blue G chromovitrectomy interventions in 59 patients admitted for macular holes, macular pucker or vitreomacular traction syndromes. Subsequent to peeling of the internal limiting membrane, six different illumination modes were enabled consecutively: mercury vapor, mercury vapor/xenon, and xenon followed by xenon combined with an amber, green or yellow spectral filter. Main outcome measure was the chromaticity spread between stained internal limiting membrane and unstained retina as a measure for the color contrast perceived by the human eye.

RESULTS

Mean chromaticity scores were similar for all light sources: mercury vapor 7.97, mercury vapor/xenon 7.96 (p = 0.96), and xenon 7.41 (p = 0.55). Compared to xenon, the additional use of endoillumination spectral filters did not change contrast recognizability: Chromaticity scores were 9.38 for the amber filter (p = 0.13), 6.63 for the green and 7.02 for the yellow filter (p = 0.37 and 0.64, respectively). When comparing the different filters head-to-head, the amber filter was superior to the green filter (p = 0.03), while the yellow was intermediate and not significantly different from either the amber (p = 0.08) or the green filter (p = 0.51).

CONCLUSIONS

Color contrast perceptibility during Brilliant Blue G assisted chromovitrectomy is similar with mercury vapor, mercury vapor/xenon or xenon light sources. Spectral filters do not decrease color contrast recognizability. Head-to-head comparison shows a significant advantage for the amber over the green filter with respect to contrast generation, the yellow filter is intermediate. As spectral filters are known to greatly reduce retinal light toxicity, we suggest donor eye studies to validate whether the amber filter should be generally recommended for Brilliant Blue G chromovitrectomy.

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.