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: 4.02). 02/1997; 123(1):54-61. DOI: 10.1016/S0002-9394(14)70992-4
Source: PubMed

ABSTRACT 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.

  • [Show abstract] [Hide abstract]
    ABSTRACT: This study aimed to compare the surgical outcomes of mitomycin C trabeculectomy glaucoma drainage device (GDD) surgery and laser neodymium:YAG (Nd:YAG) cyclophotocoagulation (CPC) in the management of intractable glaucoma after penetrating keratoplasty (PKP) in a retrospective study. Interventional case series. The medical charts of consecutive patients who had pre-existing glaucoma or who developed glaucoma after PKP and underwent a surgical procedure to control the glaucoma at the University Eye Associates of Boston University Medical Center, New England Eye Center, and Massachusetts Eye and Ear Infirmary between January 1991 and July 1995 were reviewed. Follow-up ranged from 6 months to 4 years after the glaucoma procedure. A total of 38 patients were included consisting of 17 patients who underwent mitomycin C, 10 patients who underwent GDD surgery, and 11 patients who had CPC. Mitomycin C trabeculectomy, GDDs, or Nd:YAG CPC to control glaucoma after PKP was performed, Graft status, postoperative intraocular pressure (IOP), and visual acuity were the main outcome measures. There were no differences among the three groups with respect to the follow-up time after the corneal graft operation (P = 0.15) or after the glaucoma operation (P = 0.98). At the final follow-up, the average decrease in the IOP was 17 mmHg (P < 0.001) after mitomycin C, 15 mmHg (P = 0.003) after GDD surgery, and 14.4 mmHg (P = 0.001) after CPC. There were no differences in the proportion of patients who developed postoperative IOP above 20 mmHg (P = 0.50) and in the proportion who developed hypotony (P = 0.10) among the three groups. Two grafts failed after mitomycin C and one failed after CPC. Among the three procedures, there were no differences in the proportion of patients who experienced either an improvement (P = 0.14) or a decrease (P = 0.22) in the visual acuity by more than one line after the glaucoma procedure. One patient each in the GDD group and the CPC group lost light perception after the procedure. The risk of graft failure was almost three times higher for each additional PKP (odds ratio = 2.80, P = 0.02). No differences were found among the three glaucoma procedures with respect to controlling IOP and graft failure. There was a trend for patients treated with CPC to have a higher incidence of graft failure, glaucoma failure, hypotony, and visual loss by more than one line, although this was not statistically significant. The number of PKPs was associated with graft failure, independent of the surgical procedure.
    Ophthalmology 08/1998; 105(8):1550-6. DOI:10.1016/S0161-6420(98)98046-0 · 6.17 Impact Factor
  • Source
    British Journal of Ophthalmology 10/1998; 82(9):1083-9. DOI:10.1136/bjo.82.9.1083 · 2.81 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To assess clinical outcomes and establish the incidence and management of a hypertensive phase (HP) (defined as intraocular pressure [IOP] > 21 mmHg in the first 6 postoperative months) in patients with Ahmed glaucoma valve implant. Retrospective noncomparative case series. A total of 85 patients were included in the current study, including consecutive patients who had intractable glaucoma and underwent Ahmed valve implant insertion at the University Glaucoma Center, Tampa, Florida (DWR and WEL) and the Massachusetts Eye and Ear Infirmary (PAN) between January 1993 and June 1997. Only patients with a minimum of 6 months' follow-up were included. Ahmed glaucoma valve implant insertion to control intractable glaucoma was performed. Success was defined as IOP less than 22 mmHg and greater than 4 mmHg on the last two visits, a decrease of no more than two lines in the visual acuity and no additional surgical interventions to control IOP. The cumulative probability of success at 12 months was 77%. A total of 26 patients (30.6%) failed during the study period, and 70 patients (82%) exhibited HP. Hypertensive phase peaked at 1 month after the operation and stabilized at 6 months. There were 34 patients (48%) with HP who were controlled with additional medications: 14 (20%) with needling and 5-fluorouracil injections and 20 (28%) who needed secondary surgical intervention. There were 8 patients (9.4%) who exhibited hypotony (< 5 mmHg) on postoperative day 1 and 3 (3.5%) at 3 months. Visual acuity returned to baseline between 3 and 6 months after the operation. The major complications associated with the valve were hyphema in 14 cases (16.5%), suprachoroidal hemorrhage in 4 cases (4.7%), end-plate exposure in 10 cases (11.7%), tube exposure in 6 cases (7%), tube block in 4 cases (4.7%), loss of vision in 5 cases (5.8%), and corneal graft failure in 4 (30%) of 13 cases with clear grafts. The overall success rate is comparable to that of prior studies using different implants. The majority of the patients exhibit an HP that peaks at 1 month, with gradual stabilization over 6 months. One third of the patients needed secondary surgical intervention to control the HP. The incidence of postoperative hypotony and flat or shallow anterior chambers is very low after Ahmed glaucoma valve insertion.
    Ophthalmology 10/1998; 105(10):1968-76. DOI:10.1016/S0161-6420(98)91049-1 · 6.17 Impact Factor
Show more