Richard P. Wilson

Reversal of optic disc cupping after glaucoma surgery analyzed with a scanning laser tomograph

Abstract Objective To detect and quantitate changes in optic nerve morphology after glaucoma surgery using the Heidelberg Retina Tomograph (HRT, Heidelberg Instruments, Heidelberg, Germany). Design Nonconsecutive observational case series. Participants and intervention The authors prospectively enrolled 21 adult patients undergoing incisional glaucoma surgery for progressive glaucoma damage. Quantitative analysis of the optic nerve head by scanning laser tomography and automated perimetry were performed before and after glaucoma surgery. Main outcome measures Changes in optic nerve parameters were subjected to linear regression analysis with respect to percent of postoperative reduction of intraocular pressure (IOP), as well as with respect to age, refraction, preoperative cup:disc ratio, and change in visual field parameters. Results Seventeen patients had pre- and postoperative images suitable for analysis. Mean IOP at the time of image acquisition before surgery was 30.5 ± 12 mmHg, and after surgery 11.8 ± 5.2 mmHg (mean follow-up, 26 ± 7 weeks). Eleven of 13 (85%) patients having IOP reduction of greater than 40% showed improvement in optic disc parameters. All four patients with less than 25% reduction in IOP showed worsening of most parameters. Changes in optic disc parameters were highly correlated with percent IOP reduction and with age. The parameters in which change most strongly correlated with percent change of IOP were cup area, rim area, cup:disc ratio, and mean cup depth (each, P P P = 0.025). Conclusion Most patients showing a 40% lowering of IOP after glaucoma surgery show improved optic nerve morphology as measured by the HRT. The amount of improvement correlated highly with the percent reduction of IOP.

Trabeculectomy Is Associated with Retrobulbar Hemodynamic Changes: A Color Doppler Analysis

PURPOSE To determine whether color Doppler hemodynamic changes occur in the retrobulbar circulation after trabeculectomy. METHODS The authors prospectively enrolled 20 patients undergoing trabeculectomy and performed color Doppler imaging of both eyes before surgery and then at approximately 2-, 5-, and 14-week intervals after surgery. The systolic maximum velocity, mean velocity, end-diastolic velocity, and vascular resistance (resistance index) of the central retinal artery, nasal and temporal short posterior ciliary arteries, and ophthalmic arteries were determined. Statistical comparison of the preoperative and postoperative measures were performed on both the operative and nonoperative eye using the paired Students t test. RESULTS A statistically significant increase was observed in the mean and end-diastolic velocity and a significant decrease in the vascular resistance of the central retinal artery and both short posterior ciliary arteries at nearly all postoperative intervals (25 of 27 preoperative and postoperative comparisons; P < 0.05) The ophthalmic artery, while showing an increased velocity at all intervals, only attained a statistically significant increase in one of three postoperative intervals for mean velocity and two of three intervals for end-diastolic velocity (P < 0.05). There were no notable changes in resistance. The nonoperative eye did not show a statistically significant change in velocity or in resistance in the central retinal artery or either nasal or temporal short posterior ciliary artery at any interval (0 of 27 preoperative and postoperative comparisons for mean velocity, end-diastolic velocity, and resistance index.) CONCLUSION Sustained increases in mean velocity and end-diastolic velocity and decreases in resistance index were observed in the central retinal artery and the short posterior arteries with clinically attainable reductions in intraocular pressure after trabeculectomy in patients with chronic glaucoma. These findings are consistent with, but not diagnostic of, increased blood flow through these vessels.

Results of alloplastic tube shunt procedures before, during, or after penetrating keratoplasty.

The association of glaucoma and penetrating keratoplasty presents a difficult management problem, particularly when medical therapy and conventional glaucoma surgery have failed. We have found alloplastic tube shunt surgery to be an effective method for intraocular pressure control in glaucomatous eyes subjected to penetrating keratoplasty. We report 46 patients who underwent alloplastic tube shunt implantation before (13 patients, group A), in combination with (17 patients, group B), or after (16 patients, group C) penetrating keratoplasty. All groups had significantly lowered intraocular pressure postoperatively. The most common complication was graft failure, in 31% of patients in group A, 29% in group B, and 44% in group C. Other postoperative complications and results including visual outcome are reviewed. Because the management of advanced glaucoma in patients undergoing keratoplasty is difficult, alloplastic tube shunt implantation should be considered.

Effects of topical mitomycin C on primary trabeculectomies and combined procedures

The charts were reviewed of all patients who underwent primary trabeculectomies (group 1) or combined procedures (phacoemulsification + intraocular lens implantation + trabeculectomy--group 2) and received intraoperative mitomycin C (0.4 mg/ml) between 1991 and 1992 at Wills Eye Hospital. A total of 54 eyes of 54 patients were included: 39 in group 1 and 15 in group 2. Intraocular pressure was controlled successfully in 97.4% of eyes in group 1 (mean follow up 6.7 months), and in 93.3% in group 2 (mean follow up 6.8 months). Main complications included choroidal detachment (n = 15), shallow anterior chamber (n = 9), cataract formation (n = 8), and hypotony maculopathy (n = 3). The use of mitomycin C in primary trabeculectomies and combined procedures is associated with high success rates. However, it may be associated with unacceptable risks of vision threatening complications related to excessive filtration.

Laser Iridectomy: A Controlled Study Comparing Argon and Neodymium:YAG

Laser peripheral iridectomies were performed on both eyes of 38 patients with acute or chronic primary angle-closure glaucoma or with narrow angles capable of closure. The right eye was treated with the neodymium YAG laser (Nd:YAG) and the left eye with the argon laser. Patients were followed for a minimum of eight months. The mean number of applications to produce iris penetration was six with the Nd:YAG laser and 73 with the argon laser. Visual acuity, postoperative intraocular pressure (IOP), corneal changes, and pigment dispersion were similar in the two groups. Microhyphema was more prevalent in the Nd:YAG iridectomy group. Pupillary distortion, iritis, and late failure of patency were more frequent in the argon laser group. Nd:YAG laser iridectomies require fewer applications and produce less inflammation. This controlled study demonstrates that when properly and carefully performed, the Nd:YAG laser is at least as effective and appears to be as safe as the argon laser for performing peripheral iridectomies.

The Place of Timolol in the Practice of Ophthalmology

Timolol has become so populat with ophthalmologists that it is prescribed 44% of the time when an anti-glaucoma drop is needed. This popularity is due to its newness and the publicity it has received, its effectiveness in most types of glaucoma, and the apparent scarcity of side effects. This paper looks at the first 489 patients treated with timolol at Wills Eye Hospital and the side effects encountered. These include blurring of vision, burning and pain, bradycardia and heart failure, hallucinations, dilated pupils, headaches, dizziness, hypotony, allergy, asthma, impotence, drowsiness, anxiety, emotional lability, and nausea.

Neodymium-YAG Laser Iridectomies in Glaucoma Associated With Closed or Occludable Angles

A review of our first 200 neodymium-YAG laser iridectomies performed over a two-year period in various forms of glaucoma showed patent iridectomies in 180 of 182 eyes (99% success) at the last examination (one to 26 months postoperatively). Both failures had preexisting chronic uveitis. Eighteen eyes were lost to follow-up. Complications included intraocular pressure increased more than 10 mm Hg in 54 eyes (30%), hemorrhage in 36 eyes (20%), iritis in 21 eyes (11.5%), posterior synechiae in 13 eyes (7%), corneal changes in seven eyes (4%), and pupillary distortion in six eyes (3%). With experience, fewer applications are required to penetrate the iris, and retreatment to obtain patency is less likely to be needed.

Risk factors for the development of Tenon's capsule cysts after trabeculectomy

Tenons capsule cysts (TCCs) are a complication of glaucoma filtering surgery. They are frequently associated with substantial elevations in intraocular pressure (IOP) beginning 2 to 8 weeks postoperatively. To determine the incidence and possible risk factors for the development of TCCs, case records of all patients who received trabeculectomy over a 4-year period at the Wills Eye Hospital were reviewed. The incidence of TCCs was 28% in those who underwent trabeculectomy. Characteristics of patients after trabeculectomy in whom TCCs developed were compared with patients after trabeculectomy in whom TCCs did not develop. Both univariate and multivariate techniques were used to assess the association of characteristics associated with the development of TCCs. Factors associated with increased risk (P less than 0.05) were: history of prior TCCs, argon laser trabeculoplasty, male gender, and the use of preoperative sympathomimetics. The use of a compression shell was associated with decreased risk (P less than 0.05).

Timolol: Its Effectiveness in Different Types of Glaucoma

A study is presented on the effectiveness of timolol maleate in the treatment of 76 cases of various types of glaucoma. Timolol lowered intraocular pressure significantly in almost every diagnostic category, although there was marked variability within the diagnostic categories themselves. The therapeutic trial approach is suggested as an aid in selecting persons who will respond adequately to timolol drops.

Aqueous Tube-shunt Implantation and Pars Plana Vitrectomy in Eyes With Refractory Glaucoma

We reviewed the surgical outcome of 20 eyes of 20 consecutive patients who had undergone combined aqueous tube-shunt implantation and vitrectomy for complicated glaucoma associated with vitreoretinal disorders. After a mean follow-up of 10.39 +/- 5.43 months, visual acuity remained stable or improved in 13 patients (65%), and intraocular pressure was controlled (< 22 mm Hg) in 15 (75%). The most common complications were corneal edema (seven eyes) and choroidal effusion (three eyes). Combined tube-shunt implantation and pars plana vitrectomy may successfully control intraocular pressure and maintain preoperative visual acuity in refractory glaucoma associated with vitreoretinal disorders.