Evaluation of xenon, light-emitting diode (LED) and halogen light toxicity on cultured retinal pigment epithelial cells

Retrospective Comparison of Intraoperative Parameters, Efficacy and Safety in Cataract Surgery Between Halogen and Light-Emitting Diode (LED) Illuminated Surgical Microscope

Purpose

The objective was to compare the operative time, ultrasound time, efficacy and safety of phacoemulsification with IOL insertion between using halogen and light-emitting diode (LED) illuminated microscope.

Patients and Methods

Two hundred and twenty-seven surgical charts of cataract patients who underwent phacoemulsification with IOL insertion between June 2018 and October 2020 were reviewed. There were 113 cases operated on under halogen-illuminated microscope (Carl Zeiss OPMI LUMERA S7^®) and 114 cases operated on under light-emitting diode (LED)-illuminated microscope (Leica PROVEO 8^®). All cases were operated on by the same surgeon (S.T.). The difference in operative time and ultrasound time between two groups was compared by independent samples t-test. The proportion of cases with 3-months BCVA that was better than 20/30 and the proportion of cases with intraoperative complications from the operation between two groups were compared by Pearson’s Chi-squared test.

Results

The mean ultrasound time was 121.29±53.60 seconds in halogen group and 123.98±61.53 seconds in LED group. The mean difference was −2.69±8.44 seconds which was not statistically significant (95% CI, −19.35 to 13.97; p=0.573). The mean operative time was 19.83±4.77 minutes in the halogen group and 17.20±3.02 minutes in the LED group. The mean difference was 2.63±0.53 minutes (95% CI, 1.59 to 3.67; p < 0.001). The cases with BCVA better than 20/30 was 93.69% in halogen group and 95.49% in LED group. The proportion of cases with intraoperative complications was 3.53% in halogen group and 2.63% in LED group. The difference of both proportions was not statistically significant (p=0.553 and p=0.692, respectively).

Conclusion

This study shows statistically significant operative time reduction with LED microscope. This evidence could be used for making the decision to switch from halogen microscope to LED microscope. Upgrading to LED-illuminated microscope might be beneficial for productivity improvement if there were at least six to seven cases operated on per day. The ultrasound time, efficacy, and safety showed no significant difference.

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.