ISSN: 1300-0365
Dil: Türkçe
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Argon Laser Photocoagulation Spot Size Errorsdue To The Refraction And Accomodation
Tansu Erakgün*, Önder Üretmen*, Sait Şen**, Sinan Emre***,Sait Eğrİlmez*, Cezmi AkkIn****
* Uz.Dr., Ege Üniversitesi Tıp Fakültesi Hastanesi Göz Hastalıkları AD** Uz.Dr., Ege Üniversitesi Tıp Fakültesi Hastanesi Patoloji AD,*** Asist.Dr., Ege Üniversitesi Tıp Fakültesi Hastanesi Göz Hastalıkları AD,**** Doç.Dr., Ege Üniversitesi Tıp Fakültesi Hastanesi Göz Hastalıkları AD, İZMİR
Purpose: Ocular diopter scale calibration of the laser photocoagulation instrument, refractive and accomodative state of the surgeon and the laser spot magnification factor of the fundus lens are the factors effecting spot size of the laser burn. Focusing the laser spot in the unproper refractive conditions will produce errors in the spot size. We experimentaly evaluated the influence of these factors on the spot size.
Materials and Methods: By changing the ocular diopter scale calibration, refractive and accomodative state of the surgeon, laser shots of 50, 100, 200 and 500 mm. were performed on the black text printed by laser printer on regular paper by using the argon green laser photocoagulation (532 nm) with constant power and duration. For every parameter changed, spot sizes were calculated and compared respectively with paired t test.
Result: Spot sizes which were similar to the original sizes were the ones performed while the surgeon was emmetropic and not triggering accomodation and using the laser instrument whose ocular diopter setting was calibrated individually. The laser shots produced while the surgeon was in an inadvertant refractive and accomodative state and using an uncalibrated instrument erroneously larger than the original ones. These errors were more definite in the small spot sizes.
Conclusion: Laser spots performed larger than planned without changing laser power will produce decreased energy in the anterior or posterior segment laser procedures. Therefore, ocular diopter scale calibration of the laser photocoagulation instrument must be perfect and, emmetropic state of the surgeon must be obtained without unnnecessary accomodation.Keywords: Argon laser photocoagulation, spot size, refractionTurkiye Klinikleri J Ophthalmol 2001, 10:25-29
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