Controlled cyclophotocoagulation with the 940 nm laser for primary open angle glaucoma in African eyes
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“Controlled cyclophotocoagulation” is a real-time dosage control which reduces the complications of transscleral cyclophotocoagulation to a negligible amount in European eyes. Applied to a few African eyes, however, the method failed. Obviously, the physical parameters of the laser procedure need adjustment to African eyes.
Method and material
After theoretical investigations and tests in African cadaver eyes, 940 nm laser wavelength instead of 810 nm and a different fiber coupling had solved the problem of physical differences between European and African eyes to a large extent. The method was then applied to 272 eyes of 188 patients with primary open-angle glaucoma, of which it was possible to follow 26 eyes of 18 patients for at least 1 year. Median age of the patients was 63.7 years, with the youngest 16.8 years, the oldest 88.8 years. Either 16 or 24 laser spots were applied at random. If both eyes were treated, they were treated in the same session.
The average intraocular pressure (IOP) reduction after 1 year was 7.5 mmHg, with average glaucoma drug reduction from 1.5 to 1.2 substances. At least one pop spot occurred in 32% of the eyes. No statistically significant difference between 16 and 24 spots was found. No severe complications such as intraocular bleeding, hypotony <7 mmHg, choroidal detachment or phthisis were observed.
Controlled cyclophotocoagulation with the 940 nm laser is a safe method which can be applied as the first-choice treatment to African primary open-angle glaucoma eyes. Individual IOP prediction, however, is very difficult.
KeywordsCyclophotocoagulation Wavelength dependence Real-time control Radiation transport
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