June 2020
Volume 61, Issue 7
Free
ARVO Annual Meeting Abstract  |   June 2020
USE OF THERMOGRAPHY TO EVALUATE INJURIES IN REFRACTIVE SURGERIES
Author Affiliations & Notes
  • RENATO LECA
    Faculdade de Medicina do ABC, Santo Andre, SÃO PAULO, Brazil
    Ophthalmology, Universidade Federal de Sao Paulo, Brazil
  • Edmundo Velasco Martinelli
    Faculdade de Medicina do ABC, Santo Andre, SÃO PAULO, Brazil
  • Fernando Tarcha
    Faculdade de Medicina do ABC, Santo Andre, SÃO PAULO, Brazil
  • Allan Gomes Silva
    Faculdade de Medicina do ABC, Santo Andre, SÃO PAULO, Brazil
  • Gabriel Castilho Barbosa
    Faculdade de Medicina do ABC, Santo Andre, SÃO PAULO, Brazil
  • Carla Scorza
    Departamento de Neurologia e Neurociencias, Universidade Federal de Sao Paulo, Brazil
  • Fulvio Scorza
    Departamento de Neurologia e Neurociencias, Universidade Federal de Sao Paulo, Brazil
  • Fernando Fonseca
    Faculdade de Medicina do ABC, Santo Andre, SÃO PAULO, Brazil
    Departamento de Analises Clinicas, Universidade Federal de Sao Paulo, Brazil
  • Ana Luiza Lima
    Ophthalmology, Universidade Federal de Sao Paulo, Brazil
  • Alexandre Aldred
    Faculdade de Medicina do ABC, Santo Andre, SÃO PAULO, Brazil
  • Guilherme Gomes
    Departamento de Física e Ciência Interdisciplinar, Universidade de Sao Paulo, Brazil
  • Footnotes
    Commercial Relationships   RENATO LECA, None; Edmundo Martinelli, None; Fernando Tarcha, None; Allan Silva, None; Gabriel Barbosa, None; Carla Scorza, None; Fulvio Scorza, None; Fernando Fonseca, None; Ana Luiza Lima, None; Alexandre Aldred, None; Guilherme Gomes, None
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science June 2020, Vol.61, 913. doi:
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      RENATO LECA, Edmundo Velasco Martinelli, Fernando Tarcha, Allan Gomes Silva, Gabriel Castilho Barbosa, Carla Scorza, Fulvio Scorza, Fernando Fonseca, Ana Luiza Lima, Alexandre Aldred, Guilherme Gomes; USE OF THERMOGRAPHY TO EVALUATE INJURIES IN REFRACTIVE SURGERIES. Invest. Ophthalmol. Vis. Sci. 2020;61(7):913.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : Refractive surgery, although it causes very few complications and a rapid recovery of the patient, very little attention has been given to the issue of corneal temperature during this type of surgical procedure. The temperature becomes something important to be evaluated because an ablation laser is used during the procedure, which causes injuries to the tissue due to the thermal energy inserted locally in the ablation region. Thus, the idea of this study is to deepen this knowledge using a digital infrared thermal image to evaluate how invasive this procedure can be from a perspective of the thermal energy inserted in this process and its relationship with the physiology of the injured tissue.

Methods :
Thermal digital images were obtained at a distance of 40cm from the ocular surface and performed at a rate of 30 frames/s using infrared cameras, model: T540 (sensitivity <40mK/resolution 464 x 348 pixels) and A6753sc (sensitivity <30mK/640×512 pixels Flir System), the data were analyzed via software and we used infrared radiation intensity and temperature of regions of interest, ablation site, pre and post procedure eye temperature, and all areas of interest were analyzed the maximum, minimum and average temperature, and also calculated the dissipated energy in Watts. Surgery was performed in an environment with controlled temperature and humidity, ablation of the corneal surface was performed with Excimer laser, with a spherical profile of 6-7mm and maximum ablation time of 16s.

Results : Ten uneventful surgical procedures were analyzed, with the patients acclimatized in a room at 23°C and 50% relative humidity. The average global ocular surface temperature was 30.47±0.52°C after flap-elevating epithelial debridement (pre-ablation) 51°C, and the energy input is 0.26Watts / s exposure, the tissue returns to pre-exposure temperature after 3.4s after the laser is turned off. The peak temperature is closely linked to the laser exposure time, and the maximum peak observed was 36.02°C.

Conclusions : Exposure time and ocular surface lubrication are key parameters for a better fit of this methodology, as long-term incidence of laser energy can increase corneal temperature and cause injury to adjacent tissue, in addition to lubrication. Eye assists the temperature of the cornea to not reach tissue damaging limits by thermal equilibrium by evaporative water loss during the procedure.

This is a 2020 ARVO Annual Meeting abstract.

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