Allan E. Kolker

Plasma and Aqueous Humor Endothelin Levels in Primary Open-Angle Glaucoma

Purpose:Endothelins (ET) have some effects on the regulation of aqueous humor dynamics. To investigate their possible role in glaucoma, we measured plasma and aqueous humor ET levels in patients with and without primary open-angle glaucoma. Methods:Plasma and aqueous humor samples were obtained from 31 patients with primary open-angle glaucoma and 24 patients without glaucoma. Measurements were made by radioimmunoassay (RIA) for ETs with the following crossreactivities: ET-1, ET-2, and big ET-1, 100%; and ET-3, 70%. Results:The ages (mean ± SD) of the patients with primary open-angle glaucoma (72.3 ± 10 years) and normal subjects (72.8 ± 8 years) were similar (p = 0.92). There was no significant difference between plasma ET levels of the two groups (p = 0.07). However, aqueous humor ET levels (mean ± SD) were higher in the primary open-angle glaucoma group (44.26 ± 2.6 pg ml-1) than in normal subjects (42.17 ± 1.6 pg ml-1) (p = 0.001). The ratios of corresponding aqueous humor to plasma levels of ETs were ∼10% higher in the primary open-angle glaucoma group (3.76) than in normal subjects (3.41) (p = 0.0002). Conclusions:The small increase in aqueous humor endothelin levels in patients with primary open-angle glaucoma versus controls of similar age may be relevant to the understanding of the various roles of ETs in aqueous humor dynamics in these patients.

Factors Associated With Long-Term Progression or Stability in Primary Open-angle Glaucoma

PURPOSE To evaluate long-term risk factors for progression or stability in patients with primary open-angle glaucoma. METHOD We retrospectively included consecutively reviewed patients who had primary open-angle glaucoma for at least 5 years in this multicenter trial. Historical and clinical factors in these patients were evaluated for their association with stability or progression of the glaucoma. RESULTS We included 218 patients in this study; of these, 34 progressed over an average length of follow-up of 45.5 +/- 30.0 months, and 184 were stable over an average of 72.8 +/- 18.3 months. The mean intraocular pressure over the follow-up period for the progressed group was 19.5 +/- 3.8 mm Hg and for the stable group 17. 2 +/- 3.1 mm Hg (P =.001). The average standard deviation of individual intraocular pressures was greater in the progressed group (5.1 mm Hg) than the stable group (3.9 mm Hg, P =.012). Baseline characteristics indicating a greater potential to progress were a larger cup-to-disk ratio (P <.001), a greater number of medications (P =.02), older age (P.007), and worse visual acuity (P =.003). However, no difference was observed in pressure levels that prevented progression in these subpopulations compared with the total sample size. CONCLUSIONS This study suggests that lowering the intraocular pressure is important in the treatment of primary open-angle glaucoma to help prevent long-term progression. Lowering the pressure, however, is not uniformly effective in preventing progression. Additionally, risk factors for progression do not further help identify pressure levels that prevent worsening of glaucoma.

Neovascular Glaucoma After Intracapsular and Extracapsular Cataract Extraction in Diabetic Patients

A retrospective study of the rate of development of neovascular glaucoma after cataract extraction in 242 eyes of 186 diabetic patients identified neovascular glaucoma in 13 of 146 eyes (8.9%) after intracapsular extraction, in two of 17 eyes (11.8%) after extracapsular extraction with primary capsulotomy, and in zero of 53 eyes after extracapsular extraction without capsulotomy. The incidence of neovascular glaucoma was significantly lower in patients who underwent extracapsular extraction with preservation of an intact posterior capsule than in those undergoing intracapsular cataract extraction (P less than .01) or extracapsular cataract extraction with primary capsulotomy (P less than .05).

Intraocular Pressure Response to Topical Dexamethasone as a Predictor for the Development of Primary Open-Angle Glaucoma

In a retrospective study we reviewed the records of 788 subjects who had been corticosteroid tested with 0.1% dexamethasone four times daily to one eye for six weeks. All subjects had normal kinetic visual fields and optic nerve heads in both eyes at the time of testing and were followed up for a minimum of five years. Some subjects had normal baseline intraocular pressures whereas others were considered to have ocular hypertension. Of 276 individuals who were high corticosteroid responders (intraocular pressure greater than 31 mm Hg during dexamethasone administration), 36 (13.0%) developed glaucomatous visual field loss during the follow-up period. Only nine of 261 individuals (3.4%) who were intermediate responders (intraocular pressure 20 to 31 mm Hg during dexamethasone administration) and none of 251 individuals who were low responders (intraocular pressure less than 20 mm Hg during dexamethasone administration) developed glaucomatous visual field loss. However, the ability of the intraocular pressure response to dexamethasone to predict the development of glaucomatous visual field loss was not as good as the predictive power of a multivariate model that included patient age, race, baseline intraocular pressure, baseline outflow facility, baseline cup/disk ratio, and systemic hypertension.

Assessing the Utility of Reliability Indices for Automated Visual Fields: Testing Ocular Hypertensives

Monocular (right eye) visual fields were recorded with the Humphrey Visual Field Analyzer (30-2 Program) at baseline as well as 6 and 12 months later in 120 patients with established ocular hypertension. Indices of field reliability (fixation loss, less than 20%; false-positives and false-negatives, less than 33%) and field sensitivity (mean deviation [MD] and pattern standard deviation [PSD]) were examined. At baseline, 35% of patients exhibited low reliability (LR) fields, a figure which decreased to approximately 25% at 6 and 12 months, respectively. During this period, over 50% of patients produced at least one LR field, whereas 8.3% were unable to produce even one reliable field. Exhibition of a LR field appeared to be independent of patient age. Fixation errors, the major cause of LR fields, decreased by approximately 10% over the 12-month period; most patients had between 20 and 32% fixation errors. The incidence of significant defects identified by PSD was greater than that for MD; this was true for both reliable and LR fields. It is suggested that increasing the fixation loss criteria for assessing patient reliability to a 33% cutoff might substantially increase the percentage of fields graded reliable with minimal effect on the sensitivity or specificity of the test.

Krupin Eye Valve with Disk for Filtration Surgery

PURPOSE The authors evaluate a long posterior tube shunt device with a pressure sensitive valve for filtration surgery in eyes with recalcitrant glaucoma. METHODS The device consisted of an anterior chamber tube connected to an oval (13 x 18 mm) episcleral explant. The explant was designed to maximize the area of surrounding encapsulation while still allowing implantation within one quadrant. A pressure-sensitive and unidirectional slit valve in the tube provided resistance to aqueous humor flow. One-stage implantation without the use of restrictive sutures was performed in 50 eyes with various types of glaucoma unresponsive to prior glaucoma surgery. RESULTS Mean (+/- standard error of the mean) preoperative intraocular pressure (IOP) of 36.4 +/- 1.6 mmHg was reduced significantly (P < 0.001) to 8.3 +/- 1.3 mmHg on the first postoperative day. Mean anterior chamber depth (scale, 0-4+) was 3.4 +/- 0.1. Mean IOP 1 month after surgery was 14.1 +/- 1.3 mmHg. The implant was removed from four eyes due to IOP failure (1 eye), external erosion (2 eyes), or endophthalmitis (1 eye). A suprachoroidal hemorrhage occurred in one eye on the first postoperative day. Diplopia developed in one eye after surgery. Mean IOP at last follow-up examination (mean, 25.4 +/- 2.4 months; range, 16-36 months) was 13.1 +/- 1.3 mmHg. Intraocular pressure was 19 mmHg or lower in 80% of the eyes, 59% of which were without adjunctive antiglaucoma medications. CONCLUSIONS Design features of the Krupin Eye Valve with Disk result in a large area of encapsulation in a single ocular quadrant which functions as an external reservoir for passage of aqueous humor. The valve portion facilitates maintenance of anterior chamber depth during the early postoperative interval. This new therapeutic device can be effective in the long-term control of IOP in glaucomatous eyes not responsive to prior filtration surgery with adjunctive antimetabolite therapy.

Acetazolamide and Urolithiasis

Abstract: Interviews were conducted with 515 individuals between the ages of 20 and 80 years to gather data on acetazolamide therapy and the occurrence of urolithiasis. One hundred forty-eight patients were treated with chronic oral acetazolamide therapy for one week to 348 months (mean 40.9 months). The overall occurrence of individuals developing one or more stones was significantly higher in the group treated with acetazolamide than in the group not treated with acetazolamide ( P = 0.01, logistic multiple regression). Twelve patients developed one or more stones during acetazolamide therapy (interval between the initiation of therapy and the occurrence of the first stone was one to 108 months, mean 14.4 months. The rate of individuals developing one or more stones per year during acetazolamide treatment was 11 times higher than the rate in the group not treated with acetazolamide. The rate of individuals developing one or more stones per year during acetazolamide treatment was 15 times higher than the rate in the acetazolamide group prior to the initiation of acetazolamide therapy. Nine of the 12 individuals (75%) who developed calculi during acetazolamide therapy did so within the first 12 months of treatment. Ten of these patients were maintained on acetazolamide therapy and five (50%) developed a second stone in one to 88 months (mean 29.2 months). Eight patients with a history of a single episode of idiopathic urolithiasis were treated subsequently with acetazolamide (mean duration of therapy 28.8 months) without developing a second stone. The results of this study support the clinical impression that chronic acetazolamide therapy is associated with an increased occurrence of urolithiasis.

Intraocular Pressure the Day of Argon Laser Trabeculoplasty in Primary Open-angle Glaucoma

Argon laser trabeculoplasty was performed in one eye of 57 phakic patients with primary open-angle glaucoma. The eyes received a mean of 78 +/- 7 treatments over 360 degrees to the anterior trabecular meshwork. The power was titrated to produce blanching without bubble formation. Increased intraocular pressure (range +1 to +22 mmHg) occurred in 30 of the 57 (53%) eyes 1 hour after treatment. Eight (14%) of these eyes had a clinically significant elevation defined by all of three criteria: (1) an intraocular pressure greater than 30 mmHg, (2) greater than a 30% increase over the mean prelaser intraocular pressure, and (3) greater than a 10 mmHg increase over the peak prelaser diurnal intraocular pressure curve. These eight patients received either oral glycerine or acetazolamide. A rebound increase in intraocular pressure requiring repeat medical treatment occurred in four of the eight eyes. Two additional eyes without a pressure elevation 1 hour after treatment showed a later elevation. This was first detected 4 hours postoperatively in one eye and 7 hours after treatment in another eye. The 1-hour postoperative measurement detected most patients with clinically significant increased intraocular pressure (8 of 10 eyes) but these required continued observation for rebound increases. Patients with advanced glaucomatous visual field loss should also be followed closely to detect late increases in intraocular pressure (2 of 10 eyes).

Comparative results of combined procedures for glaucoma and cataract: II. Limbus-based versus fornix-based conjunctival flaps

BACKGROUND AND OBJECTIVE One of the variables to be considered in a combined procedure for glaucoma and cataract is the type of conjunctival flap to be used. The objective of this study was to compare the effects of limbus-based and fornix-based conjunctival flaps on postoperative long-term intraocular pressure (IOP) control and visual acuity after combined trabeculectomy with phacoemulsification. PATIENTS AND METHODS The authors retrospectively reviewed the charts of 189 patients (215 eyes) who underwent combined trabeculectomy with phacoemulsification, posterior chamber intraocular lens (IOL) implantation, and intraoperative mitomycin-C administration and who had a minimum follow-up of 12 months. The results of the limbus-based (151 eyes) versus fornix-based (64 eyes) conjunctival incisions used in these combined procedures were compared. RESULTS In the limbus-based conjunctival flap group, 146 eyes (97%) achieved an IOP of less than 20 mm Hg, with or without medication; 62 eyes (97%) of the fornix-based conjunctival flap group (P > .05) achieved this result. A visual acuity of 20/40 or better was noted in 106 eyes (70%) in the limbus-based conjunctival flap group and in 45 eyes (70%) in the fornix-based conjunctival flap group (P > .05) at the last examination. Early wound leakage was observed more frequently in the fornix-based conjunctival flap group (8% vs 1%) (P = .014); however, it was not a serious clinical problem, as only 1 eye required surgical repair. Posterior capsular opacification was found more often in the limbus-based conjunctival flap group (25% vs 14%) (P = .072) and required more frequent laser capsulotomy (22% vs 9%) (P = 0.03). CONCLUSION Limbus-based and fornix-based conjunctival flaps appear to be comparable with respect to postoperative IOP control and visual acuity after a combined trabeculectomy with phacoemulsification and posterior chamber IOL implantation in cases supplemented by intraoperative mitomycin-C.

Comparative Results of Combined Procedures for Glaucoma and Cataract: I. Extracapsular Cataract Extraction Versus Phacoemulsification and Foldable Versus Rigid Intraocular Lenses

BACKGROUND AND OBJECTIVES The refinements of small-incision cataract surgery by phacoemulsification with foldable intraocular lens (IOL) implantation have recently permitted new options for combined trabeculectomy with cataract extraction. The objectives of this study were to compare the long-term intraocular pressure (IOP) control and visual outcome between trabeculectomies combined with extracapsular cataract extraction (ECCE) versus those with phacoemulsification, and to analyze these same factors for foldable versus rigid IOLs. PATIENTS AND METHODS The authors retrospectively reviewed the charts of 311 patients (397 eyes) who underwent combined trabeculectomy with cataract extraction and posterior chamber IOL implantation. In all of the surgeries, releasable scleral flap sutures were used. The mean follow-up was 22.9 +/- 15.1 months, with a minimum follow-up of 12 months. RESULTS Trabeculectomy combined with phacoemulsification had a lower postoperative complication rate and was more effective than trabeculectomy combined with ECCE in reducing IOP to less than 20 mm Hg with or without medication (95% vs 82%) and in improving vision to levels of 20/40 or better (71% vs 52%) (P < .001). Regarding IOLs, foldable silicone lenses were found to be an effective alternative to polymethylmethacrylate lenses in combined surgeries in terms of a controlled IOP of less than 20 mm Hg (97% vs 97%) and visual recovery to 20/40 or better (78% vs 63%). CONCLUSION The combination of trabeculectomy with releasable scleral flap sutures and small incision cataract surgery with foldable IOL implantation has improved postoperative IOP control and visual rehabilitation.