Guy J Ben Simon

Publications (3)1.85 Total impact

• Article: An augmented trabeculectomy for neovascular glaucoma.

  Elie Dahan, Guy J Ben Simon
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  ABSTRACT: To report on a new surgical technique for neovascular glaucoma (NVG) in patients with proliferative diabetic retinopathy or retinal vein occlusion. Fourteen eyes of 13 patients underwent an augmented trabeculectomy for NVG between January 2000 and February 2003. The augmented trabeculectomy consisted of a 7 × 5 × 5 mm trapezoidal scleral flap, a 6 × 4 × 4 mm deep sclerectomy, application of mitomycin C (MMC) 0.2% for 3 minutes in the deep scleral bed, a 2 × 1 mm trabeculectomy, and the use of a hydrophilic implant (T-flux; Carl Zeiss Meditec, Wetzlar, Germany) as a wick drain connecting the posterior chamber and the deep sclerectomy via a peripheral iridectomy. Whenever the intraocular pressure (IOP) rose above 20 mm Hg, the site of filtration was surgically revised and MMC 0.2% was reapplied in the deep scleral bed. IOP decreased from a mean of 38.7 ± 5.2 mm Hg preoperatively to a mean of 17.3 ± 5.2 mm Hg postoperatively after a mean follow-up of 32 ± 12 months (P = .001, Wilcoxon signed-ranked test, two related samples). Mean visual acuity improved from 20/350 to 20/170 (P = .034). Seven eyes (50%) needed one surgical revision and one eye (7%) needed two surgical revisions within 3 months from the first operation to maintain an IOP of less than 21 mm Hg. The modified trabeculectomy augmented by MMC 0.2% and the use of the T-flux as a wick drain can provide adequate IOP control in NVG caused by proliferative diabetic retinopathy or retinal vein occlusion. To maintain an IOP of less than 21 mm Hg without anti-glaucoma medications, surgical revisions of the filtration site are necessary in at least 50% of patients.
  Ophthalmic Surgery Lasers and Imaging 05/2011; 42(3):196-201. · 0.62 Impact Factor
• Article: Increased levels of transforming growth factor-betal and -beta2 in the aqueous humor of patients with neovascular glaucoma.

  Xiao-Bo Yu, Xing-Huai Sun, Elie Dahan, Wen-Yi Guo, Shao-Hong Qian, Fan-Rong Meng, Yue-Lian Song, Guy J Ben Simon
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  ABSTRACT: To measure the concentrations of transforming growth factor-betal and beta2 (TGF-beta1 and TGF-beta2) in the aqueous humor of patients with neovascular glaucoma (NVG). Patients were divided into four groups: NVG secondary to central retinal vein occlusion (group 1), NVG secondary to proliferative diabetic retinopathy (group 2), central retinal vein occlusion without rubeosis (group 3), and senile cataract (group 4). The total TGF-beta 1 and TGF-beta2 concentrations in the aqueous humor of the four groups were measured by enzyme linked immunosorbent assay. The mean concentrations of total TGF-betal were 600.7 +/-436.7 microg/mL in group 1, 802.0 +/-359.5 pg/mL in group 2, and undetectable in groups 3 and group 4 (P < .05). The mean concentrations of total TGF-beta2 were 6,307.9+/- 2,206.2 microg/mL in group 1, 5,908.0+/-2,033.2 microg/mL in group 2, 899.7+/- 425.6 microg/mL in group 3, and 385.7 +/-89.9 microg/mL in group 4. The total TGF-betal and TGF-beta2 concentrations in groups 1 and 2 were significantly higher than those in groups 3 and 4, whereas the total TGF-beta2 concentration in group 3 was significantly higher than that in group 4 (P < .05). There was no significant difference in the TGF-betal or TGF-beta2 concentrations between groups 1 and 2 (P> .05). The abnormally high concentrations of TGF-betal and TGF-beta2 in the aqueous humor of patients with NVG may explain some aspects of the pathogenesis of NVG and the high failure rate of filtering operations in NVG.
  Ophthalmic Surgery Lasers and Imaging 38(1):6-14. · 0.62 Impact Factor
• Article: Comparison of the efficacy and longevity of nonpenetrating glaucoma surgery with and without a new, nonabsorbable hydrophilic implant.

  Elie Dahan, Emilie Ravinet, Guy J Ben-Simon, Andre Mermoud
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  ABSTRACT: To compare the efficacy and longevity of nonpenetrating glaucoma surgery with and without the use of a nonabsorbable hydrophilic implant at the Oxford Eye Centre, Johannesburg, South Africa, and the Glaucoma Unit, Jules Gonin Ophthalmic Hospital, Lausanne, Switzerland. In a nonrandomized, prospective study between March 1997 and December 2001, 48 eyes of 32 patients aged 18 to 86 years with primary open-angle glaucoma underwent nonpenetrating glaucoma surgery; 25 eyes with the implant and 23 eyes without it. Intraocular pressure (IOP) was recorded preoperatively and postoperatively at 1, 7, and 14 days, at 1, 3, and 6 months, and thereafter every 6 months. The mean preoperative IOP was 27.5 +/- 11.8 mm Hg (range, 20 to 64 mm Hg) in the implant group and 24.8 +/- 7.1 mm Hg (range, 16 to 38 mm Hg) in the control group. During the first 18 months of follow-up, both groups showed identical IOP progression and the mean IOP remained less than 14 mm Hg. After 2 years of follow-up, the IOP started to rise in the control group but remained stable in the implant group. After 30 months, the mean IOP was 12.4 +/- 2 mm Hg and the IOP decrease in percentage was 62% +/- 6% in the implant group (n = 13) versus 16.1 +/- 3 mm Hg and 34% +/- 13% in the control group (n = 15) (mean IOP, P = .0022; mean IOP decrease in percentage, P = .01). During the first 18 months, there was no difference in the outcomes between the two groups. After 2 years of follow-up, the mean IOP was lower and the IOP decrease in percentage was greater in the implant group compared with the control group.
  Ophthalmic Surgery Lasers and Imaging 34(6):457-63. · 0.62 Impact Factor