DFPE, partially fluorinated ether: a novel approach for experimental intravitreal tamponade.

PURPOSE: To evaluate decafluoro-di-n-pentyl ether (DFPE) as a vitreous tamponade by examining ocular tolerance in rabbits' eyes. METHODS: Thirteen rabbits were divided into 4 groups after mechanical vitrectomy and were followed up to 12 months. The tamponade remained in the eye for 6 months in group 1 (DFPE) and Group 3 (DFPE and silicone oil) and for 12 months in group 2 (DFPE). Group 4 served as control. RESULTS: In groups 1, 2, and 3, dispersion of the fluid appeared 2 weeks postoperatively. Posterior subcapsular cataracts appeared in rabbits' eyes with large fills of DFPE (>50%). Histologic findings in groups 1 and 2 showed no detectable change in outer nuclear layer thickness. Except for some vacuolations, the inner retina was well preserved in all injected rabbits' eyes. On the electroretinography of injected rabbits' eyes, there was no effect on the a wave amplitude and b wave implicit time, but the b wave amplitude was elevated with statistical significance (P < 0.001) at 1, 3, and 6 months postoperatively but with no statistical significance (P > 0.05) after that period when compared with group 4 and unoperated fellow rabbits' eyes of each group. CONCLUSION: Decafluoro-di-n-pentyl ether demonstrated minimum adverse effects in retinal rabbits; further studies are needed before clinical use as short-term tamponade.

Pascal dynamic contour tonometry versus goldmann applanation tonometry in gas and air-filled eyes after vitrectomy surgery.

PURPOSE: To compare Pascal Dynamic Contour Tonometry with Goldmann Applanation Tonometry in eyes after vitrectomy surgery with intraocular tamponade of air, silicone oil or perfluorocarbon gas. METHODS: Prospective clinical comparative study. Eighty-two consecutive patients undergoing vitrectomy surgery with postoperative air, gas or oil tamponade were recruited. Intraocular pressure was measured with both devices. RESULTS: Mean Goldmann intraocular pressure was 16.6 mmHg (range, 1.0-46.0; SD = 8.80) and the mean Pascal intraocular pressure was 21.70 (range, 4.7-58.5; SD = 9.8) The mean difference between the Pascal and Goldmann readings was 5.09 mmHg (range, -14.7 to +12.9; 95% CI = 4.2-6.0; SD, 4.0; P < 0.001). Mean differences for the different tamponades were 5.09 mmHg for silicone oil, 4.02 mmHg for air, and 5.38 mmHg for perfluorocarbon gas. CONCLUSION: Pascal dynamic contour tonometry gives readings that are highly correlated with Goldmann applanation tonometry, but on average 5 mmHg higher in eyes after vitrectomy surgery with air, gas or silicone oil tamponades. The difference between Goldmann and Pascal readings does not appear to be altered by the presence of a scleral buckle, or the size of the intraocular gas bubble.

Preferred retinal locus in macular disease: characteristics and clinical implications.

PURPOSE: To investigate the location and fixation stability of preferred retinal locations (PRLs) in patients with macular disease, and the relationship among areas of abnormal fundus autofluorescence, the PRL and visual sensitivity. METHODS: Fifteen patients (15 eyes) were studied. Seven had Stargardt disease, 1 bull's eye maculopathy, 5 age-related macular degeneration, 1 Best disease, and 1 pattern dystrophy. All tested eyes had areas of abnormal fundus autofluorescence. The PRL was evaluated with fundus photography and the Nidek microperimeter. Visual field sensitivity was measured with the Nidek microperimeter. RESULTS: Of the 15 eyes, 4 had foveal and 11 had eccentric fixation. Eccentric PRLs were above the atrophic lesion and their stability did not depend on the degree of eccentricity from the fovea. Visual sensitivity was markedly decreased in locations corresponding to hypofluorescent areas. Sensitivity was not decreased in hyperfluorescent areas corresponding to flecks but was decreased if hyperfluorescence was in the form of dense annuli. CONCLUSION: Eccentric PRLs were in the superior retina in regions of normal fundus autofluorescence. Fixation stability was not correlated with the degree of eccentricity from the fovea. To assess the outcomes of treatment trials it is important to use methods that relate retinal morphology to visual function.