[Evaluation of the filtering bleb using ultrasound biomicroscopy]

BACKGROUND

Sometimes in glaucomatous patients treated with trabeculectomy there is not a correlation between bleb shape and intraocular pressure. So we studied the functional anatomy of the filtering bleb by a ultrasound biomicroscope, using high frequency (50 Mhz) probe, which provides high resolution images of filtering blebs.

MATERIALS AND METHODS

A total of 46 filtering blebs of 46 patients after trabeculectomy were analyzed by ultrasound biomicroscopy (50 Mhz). Dimensions, shapes and structure of blebs were evaluated in 2 groups of patients.

RESULTS

It was possible to obtain longitudinal or transverse images of filtering blebs, to measure the height, to evaluate the reflectivity inside and to follow the route under the scleral flap. Blebs with lower reflectivity and a visible route under the scleral flap had a lower intraocular pressure while the height was not important for a good intraocular pressure.

CONCLUSIONS

So ultrasound biomicroscopy can be a useful method to study filtering blebs and also to explain the mechanisms of filtering structures in patients who underwent trabeculectomy.

[Controlled trabeculectomy and incidence of postoperative choroidal detachment]

In this study the authors report their experience with titrated trabeculectomy. It is performed as follows: tight scleral flap trabeculectomy, five or more 10/0 nylon sutures, argon laser lysis of one or more sutures (depending on the eye's postoperative condition) by means of the Hoskins lens. The aim of this technique, performed by the authors for 3 years, is to decrease atalamia and choroidal detachment. Results obtained in 70 eyes of 62 patients with chronic open-angle glaucoma are compared by means of statistical analysis with those in 70 eyes of 66 patients operated on by means of the traditional technique. The incidence of choroidal detachment is significantly reduced (P < 0.001). There is no important difference in ocular pressure and visual acuity. In conclusion, this technique is very useful in controlling and titrating the filtration rate, avoiding an excessive lowering of IOP after trabeculectomy and decreasing the complications.

[Experiences with sclerostomy with the Holmium laser]

The THC-YAG laser (holmium laser) war used to perform ab externo sclerostomies in patients affected by various types of glaucoma. This approach was employed in 48 eyes with diagnoses of medically uncontrolled chronic open angle glaucoma, plateau iris or neovascular glaucoma. Post-operatively, 5-FU was injected. At the tend of the follow-up (mean 10.22 +/- 3.4 months), in 25 eyes (52.1%) the IOP was under control without medical therapy. In 12 eyes (25.0%) it was necessary to use antiglaucomatous topical therapy, and in 11 eyes (22.9%) the IOP was uncontrolled despite therapy. The authors stress the importance of a correct pharmacological protocol before and after operation and describe the surgical technique. They confirm the validity of this approach, owing to its minical invasiveness, the possibility of repeating the procedure, and the low complication rate.

[Determination of contrast sensitivity in patients with silicone oil tamponade]

The issue of whether silicone oil has a toxic effect on the retina is still being debated. In order to verify possible retinotoxic effects, the authors studied the variations of retinal function by means of computerized perimetry on patients who had undergone a vitreoretinal operation with injection of silicone oil in the vitreous cavity. Silicone oil remained in the eyes for a period of 120 days +/- 15.

PATIENTS AND METHODS

14 patients under treatment for vitreoretinal pathologies sparing the macula underwent five examinations (Macular Threshold Test of the Humphrey Field analyzer): two examination during the period silicone oil was in the vitreous cavity (30 days after injection and 10 days before removal) and three examinations after its removal (at 30, 90, and 180 days).

RESULTS

When the paired t-test and ANOVA test were applied to our results, there were no significant differences in the light-difference sensitivity.

CONCLUSIONS

These data do not indicate that silicone oil a retinotoxic effect (revealed by means of computerized perimetry) when it is removed within 4 months.

[A new surgical procedure in angle block glaucoma]

Authors show the results obtained in 29 eyes of 29 patients with closed angle glaucoma operated with ECCE plus posterior chamber IOL implantation. After a follow up varying from 1 to 35 months (mean = 20.7) all eyes are under good control (25 without therapy, 4 with topical therapy) of I.O.P. Authors report on the "rationale" of their surgical approach: particular anatomo-functional features of the eyes affected by closed angle glaucoma. Pre-op. and post-op. biometrical and gonioscopical findings are described and discussed.