Nonpenetrating trabeculectomy with placement of a collagen drainage device

Intrascleral outflow after deep sclerectomy with absorbable and non-absorbable implants in the rabbit eye

BACKGROUND

The purpose of the study is an analysis of intrascleral drainage vessels formed in rabbits' eyes after non-penetrating deep sclerectomy (NPDS) with absorbable and non-absorbable implants, and comparison to eyes in which surgery was performed without implanted material.

MATERIAL/METHODS

NPDS was carried out in 12 rabbits, with implantation of non-absorbable methacrylic hydrogel (N=10 eyes) or absorbable cross-linked sodium hyaluronate (N=6 eyes), or without any implant (N=8 eyes). All the animals were euthanized 1 year after surgery. Twenty-one eyeballs were prepared for light microscopy and 3 were prepared for transmission electron microscope (TEM) analysis. Aqueous humour pathways were stained with ferritin in 6 eyeballs.

RESULTS

By light microscopy, small vessels adjacent to the areas of scarring were the most common abnormality. Vessel density was significantly higher in operated sclera compared to normal, healthy tissue, regardless of the type of implant used. The average vessel densities were 2.18±1.48 vessels/mm2 in non-implanted sclera, 2.34±1.69 vessels/mm2 in eyes with absorbable implants, and 3.64±1.78 vessels/mm2 in eyes with non-absorbable implants. Analysis of iron distribution in ferritin-injected eyes showed a positive reaction inside new aqueous draining vessels in all groups. TEM analysis showed that the ultrastructure of new vessels matched the features of the small veins.

CONCLUSIONS

Aqueous outflow after NPDS can be achieved through the newly formed network of small intrascleral veins. Use of non-absorbable implants significantly increases vessel density in the sclera adjacent to implanted material compared to eyes in which absorbable implants or no implants were used.

Trabeculectomy combined with deep sclerectomy and scleral flap suture tension adjustment under an anterior chamber maintainer: a new modification of trabeculectomy

The objective of this study was to investigate the efficacy and safety of trabeculectomy combined with deep sclerectomy in patients with primary open angled glaucoma (POAG) and to compare the results with those from conventional trabeculectomy. In the study 12 eyes of 10 patients operated with trabeculectomy combined with deep sclerectomy (Group I) and 16 eyes of 16 patients operated with conventional trabeculectomy surgery (Group II) were included. In the described form of combined deep sclerectomy with the trabeculectomy technique the superficial scleral flap was sutured with 10/0 monofilament, the number and tension of sutures were adjusted according to the outflow dynamics, under the scleral flap, of balanced salt solution (BSS) provided by an anterior chamber maintainer. In groups I and II all the patients were male POAG cases with mean ages of 60.0 +/- 19.4 and 67.0 +/- 7.1 years, respectively. The mean follow-up periods were 8.3 +/- 3.5 months for group I and 16.6 +/- 7.0 months for group II. Preoperative mean IOP were 29.7 +/- 8.3 and 29.1 +/- 12.8 mmHg mmHg, and average topical antiglaucomatous medications were 2.9 +/- 0.7 and 2.7 +/- 1.1 for groups I and II, respectively. Postoperatively mean IOP measurements were reduced in groups I and II to 10.5 +/- 2.9 vs. 9.6 +/- 4.8 mmHg at 1 week, 13.7 +/- 5.6 vs. 16.0 +/- 9.8 at 1st month, 12.3 +/- 6.4 vs. 17.3 +/- 8.0 at 3rd month, 11.0 +/- 4.1 vs. 15.3 +/- 5.8 at 6th month, 10.8 +/- 1.6 vs. 16.1 +/- 4.4 at 12th month, and 11.0 +/- 1.0 vs. 16.7 +/- 5.0 at 18th month. Statistical analysis revealed that mean postoperative IOP measurements for group I were significantly lower than for group II for all measurements except the first week (P < 0.05). At 12th month, the complete (IOP <22 mmHg without medication) and qualified (IOP <22 mmHg with medication) success rates were 83.3 and 100% for group I and 63.6 and 90.9% for group II. Postoperatively at 12th month, the mean number of antiglaucoma medications had fallen to 0.0 +/- 0.0 in group I and 0.81 +/- 1.1 in group II. Trabeculectomy surgery combined with deep sclerectomy and suture adjustment under an anterior chamber maintainer provided sufficient IOP decrease and diffuse bleb morphology. This technique could be used as a safe method for management of glaucoma.

Characterizing pseudoexfoliation syndrome through the use of ultrasound biomicroscopy

PURPOSE

To determine the clinical utility of ultrasound biomicroscopy (UBM) in diagnosis of pseudoexfoliation (PEX) syndrome by characterizing the lens capsule and zonules before cataract surgery.

SETTING

Veterans Administration Hospital, East Orange, and University of Medicine & Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey, USA.

METHODS

Ultrasound biomicroscopy was performed on 10 patients clinically diagnosed with PEX syndrome. The clinical diagnosis was made by the presence of fibrillin deposits on the anterior lens capsule, lack of pigment at the pupillary ruff, and poor pharmacologic dilation. Five persons without PEX were used as controls. The thickness of the anterior lens capsule was measured in 5 locations in each eye: centrally and in the peripheral lens capsule superiorly, inferiorly, nasally, and temporally. Four measurements were taken from the zonule at the thickest point on each fiber. The UBM also found the presence or absence of nodular deposits on the zonules.

RESULTS

The anterior and peripheral lens capsule in patients with PEX was thicker than that in the control group. Additionally, patients with PEX had thicker zonules than the control group and had nodular deposits present; the control group had no deposits. These differences were all significant with a 99% confidence interval.

CONCLUSIONS

A thicker anterior lens capsule and lens zonule nodules were associated with PEX. These abnormalities can be visualized with the UBM to confirm the diagnosis of PEX and identify patients at risk for operative complications.

Trabéculo-sclérectomie non perforante avec mitomycine C, sans implant

PURPOSE

Since 1998 we have been conducting a prospective study of nonpenetrating deep trabeculectomy with chronic open-angle glaucoma to evaluate the efficiency of the technique.

MATERIAL AND METHODS

The study was carried out in 55 eyes of 41 patients who suffered from open-angle glaucoma. After performing a superior scleral flap, mitomycin diluted to 0.01% was applied for 3 minutes, then the 4 x 4-mm superficial scleral flap was dissected at two-thirds deepness until reaching the cornea. The Schlemm canal and the external trabecula were surgically removed and the two points of the Schlemm canal were catheterized with a trabeculotome to ensure that the ablation was well done. If it was not, it was completed by using a trabeculotome as a guide. Postoperatively, if the filtering bleb tended to decrease or ocular pressure began to increase, the operated trabecular region was reopened with Yag laser. The filtering bleb characteristics were correlated with the normalization of intraocular pressure in the first 30 cases.

RESULTS

Preoperative pressure without treatment was 32 mmHg. Postoperative intraocular pressure without treatment was 20 mmHg or less in 79% of the eyes after 4 months, 77.5% after 6 months, 75% after 8 months and 61% after 12 months. By adding a local hypotension treatment in monotherapy, a pressure of 20 mmHg or less was obtained in 79% of the cases after 12 months. No severe complications were observed. The presence of a filtering bleb is an important factor in the normalization of postoperative pressure (p=0.0048).

CONCLUSIONS

This surgical technique provides a substantial decrease in intraocular pressure and very few complications after 12 months of follow-up.

Concave trabeculo-Descemet's membrane as an early sign of viscocanalostomy failure

PURPOSE

To correlate trabeculo-Descemet's membrane (TDM) changes with a late rise in intraocular pressure (IOP) in patients with successful viscocanalostomy.

SETTING

Consultores Oftalmológicos, Hospital Oftalmológico Santa Lucía, and Centro de Estudios Médicos e Investigación, Buenos Aires, Argentina.

METHODS

Patients who had a viscocanalostomy between July 1998 and September 2001 were retrospectively studied. Gonioscopy was performed in all patients. A subgroup of patients who had a late increase in IOP and were successfully treated with neodymium:YAG (Nd:YAG) laser goniopuncture were studied to correlate gonioscopic findings. Ultrasound biomicroscopy was performed in 10 cases. Intraocular pressure measurements were taken before viscocanalostomy and before and after Nd:YAG treatment.

RESULTS

Sixty-eight eyes of 48 patients had a viscocanalostomy to control IOP. Twenty-six eyes had a late increase in IOP and were successfully treated with Nd:YAG laser goniopuncture. Before goniopuncture, 17 eyes (65.30%) had a concave TDM. The mean IOP in these patients increased from 14.27 mm Hg to 18.73 mm Hg (range 14 to 27 mm Hg). Goniopuncture was performed a mean of 10.7 months (range 1 to 36 months) after surgery. After Nd:YAG treatment, the TDM was flat in all patients who had a concave TDM before treatment. At the last examination, the mean IOP was 13.8 mm Hg, a mean decrease of 52.24% from the baseline preoperative IOP; 61.5% of eyes had a final IOP of 14.0 mm Hg or lower.

CONCLUSIONS

A concave TDM was associated with a late IOP rise. The TDM was flat after laser goniopuncture and normalization of IOP.

Laser-assisted deep sclerectomy

PURPOSE

To study the clinical effectiveness of deep sclerectomy using the erbium:YAG (Er:YAG) laser in patients with open-angle glaucoma (OAG).

SETTING

Department of Ophthalmology, Institut Universitari Dexeus, Universitat Autonoma de Barcelona, Barcelona, Spain.

METHODS

This nonrandomized prospective clinical study was performed in 46 consecutive eyes with OAG. Seventeen patients had not received any treatment for glaucoma. Eight had received 1 medication; 14, 2 medications; and 7, 3 medications. The mean duration of treatment was 18.3 months +/- 9.4 (SD). After mitomycin-C 0.02% was administered for 2 minutes, a superficial 4.0 mm x 4.0 mm scleral flap was created and a deep 3.0 mm x 3.0 mm scleral ablation was performed with the Er:YAG laser. Schlemm's canal was removed, and the cornea was dissected to Descemet's membrane until aqueous humor percolated. The scleral flap and conjunctiva were closed. Postoperative follow-up examinations were done at 1, 3, and 7 days, 2, 3, and 4 weeks, and then every 3 months up to 15 months.

RESULTS

The mean preoperative intraocular pressure (IOP) was 28.3 +/- 6.1 mm Hg. The mean postoperative IOP was 14.1 +/- 3.5 mm Hg at 24 hours, 16.3 +/- 4.2 mm Hg at 3 months, and 15.3 +/- 2.7 mm Hg at 15 months (P <.001). There were no statistically significant differences in IOP by sex or age. There was a statistically significant difference between patients receiving no medication and those who received more than 2 medications and a treatment period longer than 1 year preoperatively (P <.006). The presence of a filtering bleb was associated with a longer period of decreased IOP (P <.007). The success rate (IOP < or =18 mm Hg without medication) was 93.47% at 1 month and 84.78% at 15 months. The number of complications was significantly lower than in previous reports of trabeculectomy. One patient lost 2 lines of visual acuity because of cystoid macular edema.

CONCLUSIONS

Deep sclerectomy using the Er:YAG laser was safe and effective in eyes with OAG. More studies are needed to analyze the mechanism of lowering IOP.

Midterm ultrasound biomicroscopy findings in eyes with successful viscocanalostomy

PURPOSE

To show tissue changes using ultrasound biomicroscopy (UBM) in eyes with controlled intraocular pressure (IOP) after viscocanalostomy.

SETTING

Consultores Oftalmológicos, Fundación Oftalmológica Argentina Jorge Malbran and Hospital Santa Lucía, Buenos Aires, Argentina.

METHODS

This retrospective noncomparative case series comprised 23 eyes of 19 patients with uncontrolled open-angle glaucoma who had viscocanalostomy and UBM and a mean follow-up of 20 months +/- 5.9 (SD) (range 12 to 30 months). The UBM measurements were taken a mean of 6.8 +/- 5.9 months (range 3 to 14 months) after the viscocanalostomy. In 7 eyes, UBM was again performed a mean of 7.8 +/- 4.6 months (range 7 to 9 months) after the first study. All patients had preoperative and postoperative IOP measurements.

RESULTS

The mean IOP at last examination was 13.3 +/- 2 mm Hg (range 8 to 17 mm Hg). One eye had evidence of a subconjunctival bleb. All eyes had a nonreflective scleral chamber and posterior to it, a hyporeflective zone. In 7 eyes in which 2 UBMs were performed, the scleral chamber was unchanged 7 to 9 months after the first study.

CONCLUSIONS

The presence of a scleral chamber and absence of a subconjunctival filtering bleb are the usual UBM findings in eyes with adequate control of IOP several months after viscocanalostomy. These findings suggest that viscocanalostomy is successful when a continuous aqueous flow through the trabeculo-Descemet's membrane is present, maintaining a scleral chamber.