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Temperature-controlled retinal photocoagulation--a step toward automated laser treatment
Stefan Koinzer1, Kerstin Schlott, Lars Ptaszynski
1Department of Ophthalmology, University of Kiel, Kiel, Germany. koinzer@auge.uni-kiel.de
Investigative Ophthalmology & Visual Science
|May 8, 2012
Summary
Temperature controlled photocoagulation (TCP) uses optoacoustics for precise retinal lesion creation. This method ensures reproducible lesion sizes, improving safety in ophthalmic laser treatments.
Area of Science:
- Ophthalmology
- Biomedical Engineering
- Laser Medicine
Background:
- Retinal laser photocoagulation can lead to overtreatment due to variable lesion effects.
- Lesion outcome depends on induced temperature and exposure duration.
- Standard photocoagulation lacks precise control over lesion size.
Purpose of the Study:
- Introduce temperature controlled photocoagulation (TCP) for reproducible retinal lesions.
- Utilize optoacoustics to determine individual exposure times.
- Enhance safety and consistency in retinal laser treatments.
Main Methods:
- Optoacoustic temperature measurement using repetitive low-energy laser pulses.
- Continuous wave (CW) photocoagulator for treatment with superimposed probe pulses.
- Algorithm development based on 1500 rabbit lesions to control exposure times in TCP.
Main Results:
- TCP achieved exposure times from 4 to 800 ms, independent of laser power (14-200 mW).
- TCP lesions had a mean diameter matching the treatment beam (130 μm), unlike standard lesions.
- Histology confirmed sparing of retinal nerve fiber and ganglion cell layers with TCP.
Conclusions:
- TCP enables uniform retinal lesion creation across a broad power range.
- TCP produces soft, reproducible lesions, minimizing tissue variation effects.
- Clinical application of TCP is expected to improve safety, especially with short exposure times.
