Search

To evaluate decafluoro-di-n-pentyl ether (DFPE) as a vitreous tamponade by examining ocular tolerance in rabbits' eyes.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.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 (P0.001) at 1, 3, and 6 months postoperatively but with no statistical significance (P0.05) after that period when compared with group 4 and unoperated fellow rabbits' eyes of each group.Decafluoro-di-n-pentyl ether demonstrated minimum adverse effects in retinal rabbits; further studies are needed before clinical use as short-term tamponade.

Patients with macular disease and central visual loss affecting the fovea often adopt an eccentric preferred retinal location (PRL). The existence of eccentric PRLs has been known for many years1; however, their characteristics are still not fully understood. Studies have shown that their location can change as a function of the type of macular disease, the luminance level, and the functional task.2-6 Information as to their location and stability is not only useful for the clinician in planning future treatment of patients with macular disease but also is essential for the correct interpretation of measures of local function such as visual field sensitivity and focal or multifocal electroretinography. The information may also prove to be an indicator of disease progression. Recently a microperimeter, the Nidek microperimeter (MP-1) (Nidek Technologies Inc., Padova, Italy) has been developed that may be a useful clinical tool for assessing the location and stability of fixation while simultaneously measuring visual field sensitivity. The MP-1 combines fundus tracking microperimetry with color fundus photography. The examiner selects a landmark with high reflectivity on the fundus and stimuli are projected onto the retina in relation to this landmark using an LCD. An automatic eye tracker compensates for eye movements. A color fundus photograph is taken at the end of the examination and a registration technique is used to overlay the perimetric and fixation results on the fundus photograph. This allows visual function to be compared to retinal morphology. The technique has the potential to improve our understanding of PRLs and of visual sensitivity of the surrounding areas of patients with macular disease. In this study the MP-1 and conventional fundus photography were used to investigate the location and fixation stability of PRLs in a group of patients with retinal disease affecting the macula. The visual sensitivity of the surrounding retinal region was measured with static perimetry and the relationship of the PRL to fundus abnormalities examined by overlaying the perimetric and fixation results onto the fundus photograph and onto the fundus autofluorescence (FAF) images. Finally the effect of an eccentric PRL on the interpretation of the results of functional tests such as the multifocal electroretinogram is discussed.

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.