BACKGROUND: The purpose of this study was to compare the effects of diode and argon laser photocoagulation (DLP and ALP) on the preretinal oxygen tension (PO2): (1) directly over photocoagulated retina and (2) in between laser lesions. METHODS: DLP or ALP was applied to avascular rabbit retina to produce grade II lesions. On the day of the oxygen measurement, a droplet of perfluorotributylamine was placed into the preretinal vitreous space over the lasered area of retina and the steady-state PO2 was measured in normoxic animals using 19F magnetic resonance spectroscopy. To determine the PO2 directly over laser lesions, small (5-microliter) droplets were placed over large (approximately 4 mm x 5 mm), confluent areas of treatment (burn area approximately 95% of the treated retinal surface area). To determine the PO2 in between laser lesions, a large (10-microliter) droplet was placed over a field of scatter photocoagulation (burn area approximately 30% of the treated retinal surface area). The theoretical basis for this approach is discussed. RESULTS: Untreated eyes had a preretinal PO2 of 22 +/- 9 mm Hg (mean +/- SD, n = 15 eyes). The preretinal PO2 was significantly higher over confluent, 12-day-old ALP or DLP lesions (51 +/- 13 mm Hg, n = 8 eyes; P < 0.01) compared to untreated eyes. However, at that time, DLP lesions had significantly higher PO2 values (60 +/- 13 mm Hg, n = 4 eyes) than did ALP lesions (42 +/- 6 mm Hg, n = 4 eyes; P = 0.04). The preretinal space in between laser lesions generally showed no significant increase in PO2 (P > 0.05) over controls on post-treatment days 1, 5, 14 and 47. The only exception was in the DLP group of eyes, in which a significant increase in PO2 over untreated or ALP-treated eyes occurred on post-treatment day 5 (41 +/- 7 mm Hg, n = 5 eyes; P = 0.01). Over photocoagulation lesions in this study, DLP produced a greater increase in preretinal PO2 compared to control values than did ALP. CONCLUSIONS: These results support the use of DLP as an alternative to ALP for the treatment of retinal vascular diseases in which hypoxia is suspected to play a role.
BACKGROUND: The purpose of this study was to compare the effects of diode and argon laser photocoagulation (DLP and ALP) on the preretinal oxygen tension (PO2): (1) directly over photocoagulated retina and (2) in between laser lesions. METHODS: DLP or ALP was applied to avascular rabbit retina to produce grade II lesions. On the day of the oxygen measurement, a droplet of perfluorotributylamine was placed into the preretinal vitreous space over the lasered area of retina and the steady-state PO2 was measured in normoxic animals using 19F magnetic resonance spectroscopy. To determine the PO2 directly over laser lesions, small (5-microliter) droplets were placed over large (approximately 4 mm x 5 mm), confluent areas of treatment (burn area approximately 95% of the treated retinal surface area). To determine the PO2 in between laser lesions, a large (10-microliter) droplet was placed over a field of scatter photocoagulation (burn area approximately 30% of the treated retinal surface area). The theoretical basis for this approach is discussed. RESULTS: Untreated eyes had a preretinal PO2 of 22 +/- 9 mm Hg (mean +/- SD, n = 15 eyes). The preretinal PO2 was significantly higher over confluent, 12-day-old ALP or DLP lesions (51 +/- 13 mm Hg, n = 8 eyes; P < 0.01) compared to untreated eyes. However, at that time, DLP lesions had significantly higher PO2 values (60 +/- 13 mm Hg, n = 4 eyes) than did ALP lesions (42 +/- 6 mm Hg, n = 4 eyes; P = 0.04). The preretinal space in between laser lesions generally showed no significant increase in PO2 (P > 0.05) over controls on post-treatment days 1, 5, 14 and 47. The only exception was in the DLP group of eyes, in which a significant increase in PO2 over untreated or ALP-treated eyes occurred on post-treatment day 5 (41 +/- 7 mm Hg, n = 5 eyes; P = 0.01). Over photocoagulation lesions in this study, DLP produced a greater increase in preretinal PO2 compared to control values than did ALP. CONCLUSIONS: These results support the use of DLP as an alternative to ALP for the treatment of retinal vascular diseases in which hypoxia is suspected to play a role.
Authors: A P Adamis; D T Shima; K T Yeo; T K Yeo; L F Brown; B Berse; P A D'Amore; J Folkman Journal: Biochem Biophys Res Commun Date: 1993-06-15 Impact factor: 3.575
Authors: L P Aiello; R L Avery; P G Arrigg; B A Keyt; H D Jampel; S T Shah; L R Pasquale; H Thieme; M A Iwamoto; J E Park Journal: N Engl J Med Date: 1994-12-01 Impact factor: 91.245
Authors: L Nicholson; N V Patrao; J Ramu; C Vazquez-Alfageme; M Muwas; R Rajendram; P G Hykin; S Sivaprasad Journal: Eye (Lond) Date: 2017-04-28 Impact factor: 3.775