Clinical Experience With the Ahmed Glaucoma Valve Implant in Eyes With Prior or Concurrent Penetrating Keratoplasties

Jules Stein Eye Institute, UCLA School of Medicine, USA.
American Journal of Ophthalmology (Impact Factor: 3.87). 02/1997; 123(1):54-61. DOI: 10.1016/S0002-9394(14)70992-4
Source: PubMed


To evaluate the Ahmed Glaucoma Valve implant, an aqueous shunting device with a unidirectional valve mechanism, in eyes with concurrent or prior penetrating keratoplasties.
Thirty-one eyes of 31 consecutive patients had placement of an Ahmed Glaucoma Valve implant. Median patient age was 65.1 years (range, 17.2 to 103.4 years). The main outcome measure was time after surgery without failure. Success was defined as no additional glaucoma surgeries or devastating visual complications, no new corneal graft failure, an intraocular pressure greater than or equal to 5 mm Hg on the last two follow-up examinations, and reduction in intraocular pressure. For eyes with preoperative intraocular pressure greater than 22 mm Hg, an average intraocular pressure of less than 22 mm Hg on the last two follow-up examinations was required. For eyes with preoperative intraocular pressure of less than 22 mm Hg, an intraocular pressure lowered by at least 20% from preoperative values was required.
Cumulative probabilities of success at 12 and 20 months (mean +/- SD) were 75.4% +/- 8.2% and 51.5% +/- 11.4%, respectively. Eleven of 31 eyes were failures. The risk of failure in eyes with prior infectious keratitis or keratouveitis was estimated to be 5.8 times greater than that associated with eyes that underwent penetrating keratoplasties for other reasons (P = .009).
Twelve- and 20-month success rates of the implant in eyes with prior or concurrent penetrating keratoplasties were comparable to those of other drainage devices. Eyes with prior infectious keratitis or keratouveitis were at increased risk of failure.

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    • "The outcomes of patients in the PKP + AGV group were in line with those of earlier reports. The frequency of successful IOP control after combined PKP and GDD implantation ranges from 65% to 95% [1-6]. Coleman et al. [6] reported a 62% success rate at 20 months in a series of 12 patients when simultaneous PKP and AGV implantation were performed. "
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    ABSTRACT: To evaluate whether a combination of penetrating keratoplasty (PKP) or pars plana vitrectomy (PPV) and Ahmed glaucoma valve (AGV) implantation affords a level of success similar to that of AGV implantation alone. Eighteen eyes underwent simultaneous PPV and AGV, 14 eyes with PKP and AGV and 30 eyes with AGV implantation alone were evaluated. Success was defined as attainment of an intraocular pressure (IOP) >5 and <22 mmHg, with or without use of anti-glaucoma medication. Kaplan-Meier survival analysis was performed to compare cumulative survival between the combined surgery groups and the AGV implantation-alone group. Cox proportional hazard regression analysis was conducted to identify factors predictive of success in each of the three groups. Mean (±standard deviation) preoperative IOP was 30.2 ± 10.2 mmHg in the PKP + AGV, 35.2 ± 9.8 mmHg in the PPV + AGV, and 36.2 ± 10.1 mmHg in the AGV implantation-alone group. The cumulative success rate at 18 months was 66.9%, 73.2%, and 70.8% in the three groups, respectively. Neither combined surgery group differed significantly in terms of cumulative success rate compared with the AGV implantation-alone group (p = 0.556, p = 0.487, respectively). The mean number of preoperative anti-glaucoma medications prescribed was significantly associated with success in the PKP + AGV implantation group (hazard ratio, 2.942; p = 0.024). Either PKP or PPV performed in conjunction with AGV implantation afforded similar success rates compared to patients treated with AGV implantation alone. Therefore, in patients with refractory glaucoma who have underlying corneal or retinal pathology requiring treatment with PKP or PPV, AGV implantation can be performed simultaneously.
    Korean Journal of Ophthalmology 12/2012; 26(6):432-7. DOI:10.3341/kjo.2012.26.6.432
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    • "Several reports have shown that using GDDs as a method of treating glaucoma, as is the case with Ahmed valve (AGV) implantation, is an effective method of controlling intraocular pressure (IOP) in glaucoma patients. In a number of studies, 50–80% of the patients experienced post-operative corneal graft rejections that affected their visual acuities (VAs) [4]–[6]. At present, there is no consensus regarding the amount of time between PKP and AGV implantation that is optimal for controlling IOP, improving graft survival, and preserving VA in patients with preexisting glaucoma. "
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    ABSTRACT: To evaluate the efficacy of Ahmed Glaucoma Valve (AGV) surgery and the optimal interval between penetrating keratoplasty (PKP) and AGV implantation in a population of Asian patients with preexisting glaucoma who underwent PKP. In total, 45 eyes of 45 patients were included in this retrospective chart review. The final intraocular pressures (IOPs), graft survival rate, and changes in visual acuity were assessed to evaluate the outcomes of AGV implantations in eyes in which AGV implantation occurred within 1 month of post-PKP IOP elevation (Group 1) and in eyes in which AGV implantation took place more than 1 month after the post-PKP IOP evaluation (Group 2). Factors that were associated with graft failure were analyzed, and the overall patterns of complications were reviewed. By their final follow-up visits, 58% of the patients had been successfully treated for glaucoma. After the operation, there were no statistically significant differences between the groups with respect to graft survival (p = 0.98), but significant differences for IOP control (p = 0.049) and the maintenance of visual acuity (VA) (p<0.05) were observed. One year after surgery, the success rates of IOP control in Group 1 and Group 2 were 80% and 46.7%, respectively, and these rates fell to 70% and 37.3%, respectively, by 2 years. Factors that were associated with a high risk of AGV failure were a diagnosis of preexisting angle-closure glaucoma, a history of previous PKP, and a preoperative IOP that was >21 mm Hg. The most common surgical complication, aside from graft failure, was hyphema. Early AGV implantation results in a higher probability of AGV survival and a better VA outcome without increasing the risk of corneal graft failure as a result of post-PKP glaucoma drainage tube implantation.
    PLoS ONE 05/2012; 7(5):e37867. DOI:10.1371/journal.pone.0037867 · 3.23 Impact Factor
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    • "For refractory glaucoma patients with a poor surgical prognosis, implants have been widely used, particularly the recently developed Ahmed glaucoma valve implant (New World Medical, Inc. Rancho Cucamonga, California, USA), which has been reported to reduce the initial hypotony after surgery, among other related complications.7-9 "
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    ABSTRACT: Ahmed glaucoma valves were implanted into the ciliary sulcus of two patients diagnosed with neovascular glaucoma with favorable outcomes. The study patients presented to our hospital with ocular pain caused by increased intraocular pressure (IOP). A thorough history was taken, and an ophthalmic examination was performed. A 71-year-old male patient and a 57-year-old female patient visited our hospital for ocular pain and persistent, elevated IOP. Each were diagnosed with neovascular glaucoma and underwent an Ahmed glaucoma valve implantation to the sulcus. After surgery, the patients maintained stable IOPs without major complications. The method of Ahmed glaucoma valve implantation into the ciliary sulcus could reduce complications caused by implantation to the anterior chamber. It is thought to be an efficient method for the maintenance of appropriate IOP after surgery.
    Korean Journal of Ophthalmology 07/2007; 21(2):127-30. DOI:10.3341/kjo.2007.21.2.127
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