Terry J. Bergstrom

Intraoperative Mitomycin versus Postoperative 5-Fluorouracil in High-risk Glaucoma Filtering Surgery

In a randomized clinical trial, the authors compared the use of postoperative subconjunctival injections of 5-fluorouracil (5-FU) in 19 eyes with a single intraoperative application of subconjunctival mitomycin (MMC) at the filtering site in 20 eyes at high risk for failure of glaucoma filtering surgery. Six months after surgery, intraocular pressures averaged 10.9 +/- 5.3 mmHg (mean +/- standard deviation) in the MMC-treated eyes versus 14.2 +/- 5.5 mmHg in the 5-FU-treated eyes (P = 0.08) and were less than or equal to 12 mmHg in 60.0% of MMC-treated eyes and 21.1% of 5-FU-treated eyes (P = 0.03). Mitomycin-treated eyes were receiving an average of 0.3 +/- 0.5 medications for intraocular pressure control, and 5-FU-treated eyes were receiving an average of 1.1 +/- 1.1 medications (P = 0.01). Drug-induced corneal epithelial defects were seen in nine 5-FU-treated eyes and in no MMC-treated eyes (P = 0.0004). These results suggest that intraoperative MMC may be a viable alternative to postoperative 5-FU, with lower overall intraocular pressures, decreased dependence on postoperative ocular antihypertensive medications, and decreased corneal toxicity.

BLEB RELATED ENDOPHTHALMITIS AFTER TRABECULECTOMY WITH MITOMYCIN C

PURPOSE To determine whether filtering blebs resulting from adjunctive use of mitomycin C (MMC) leads to an increased risk of endophthalmitis. METHODS The authors retrospectively reviewed the records of 232 consecutive trabeculectomies performed at the W. K. Kellogg Eye Center with adjunctive use of MMC from May 1990 through June 1993. Data obtained from the records included patient age, sex, race, type of glaucoma, site of filtration surgery, concentration and duration of exposure to MMC, presence of early or late bleb leakage, and the occurrence of endophthalmitis. RESULTS Three patients were lost to follow-up less than 1 month after surgery. A total of 229 eyes of 192 patients (11 women and 82 men) were included in the study. Mean follow-up of patients remaining free of infection was 18.5 +/- 10.8 months (range, 1-44 months). The overall incidence of bleb-related endophthalmitis was 2.6%. Endophthalmitis developed in 8% of patients (4 or 50) in whom an inferior approach was used and in 1.1% (2 or 179) in whom a superior approach was used (P = 0.02, Fishers exact test). The estimated odds ratio for the development of endophthalmitis after trabeculectomy with adjunctive MMC for inferior versus superior filtration sites was 7.7. CONCLUSION Short-term follow-up of trabeculectomies performed with adjunctive use of MMC demonstrates an overall incidence of endophthalmitis comparable to filtrationprocedures performed with 5-fluorouracil or without antifibrotic agents. However, inferior trabeculectomy performed with adjunctive MMC carries a significantly increased risk of bleb-related endophthalmitis compared with filters performed superiorly.

Mitomycin C versus 5-Fluorouracil in High-risk Glaucoma Filtering Surgery: Extended Follow-up

Background: With the increased use of a hand-held indirect lens and slit-lamp biomicroscopy for stereoscopic viewing of the optic nerve, the authors believe that an acquired pit of the optic nerve is more common than was recognized previously. This increased recognition has led to the awareness that the central visual field was affected frequently in the presence of such an acquired pit. Methods: The authors retrieved the charts of a series of 97 patients who had an acquired pit of the optic nerve during an 18-month period and retrospectively reviewed the automated visual fields associated with these pits using the Humphrey Visual Field Analyzer Programs 30-2 and 10-2 and looked for involvement of the central visual field. Results: In 81.7% of the acquired pits of the optic nerves, one of the central-most test points (3° from fixation) in the appropriate hemifield on the 30-2 format was depressed severely by Statpac II ( P P = 0.03). Conclusion: The authors showed that the presence of an acquired pit in an optic nerve damaged by glaucoma frequently is associated with a threat to fixation.

Clinical comparison of the Oculab Tono-Pen to the Goldmann applanation tonometer

The Oculab Tono-Pen tonometer was compared with the Goldmann applanation tonometer through studies on 197 eyes of 103 patients with glaucoma or ocular hypertension to evaluate the reliability of the Tono-Pen in determining intraocular pressure (IOP). Patients were randomized into four groups and all applanations were done by the same investigator. The Tono-Pen initially used (Tono-Pen #1) failed to calibrate after being used on 77 eyes. Tono-Pen #2 was then obtained and tested. Each Tono-Pen showed high correlation with the Goldmann readings (r greater than or equal to 0.86 in both eyes). The overall sensitivity of the Tono-Pen in detecting IOPs of 21 mmHg or higher (as measured by the Goldmann instrument) was 62.1% in right eyes, 72.4% in left eyes, with corresponding specificities of 92.6% in the right and 97.1% in the left. Given the substantial increase in sensitivity noted with Tono-Pen #2, the Tono-Pen appears adequate for screening programs where an IOP of 21 mmHg or above is considered abnormal; however, at higher IOPs (greater than or equal to 30 mmHg) the Tono-Pens tended to underestimate Goldmann IOPs. At low IOPs (less than or equal to 9 mmHg) the Tono-Pens tended to overestimate the IOPs. Perhaps with further modifications of the instrument, it could be used for clinical diagnosis and management of glaucoma patients.

Mitomycin C versus 5-Fluorouracil in High-risk Glaucoma Filtering Surgery

PURPOSE To compare the outcome of filtering surgery in high-risk patients using intraoperative mitomycin C (MMC) versus postoperative 5-fluorouracil (5-FU). METHODS In a randomized clinical trial, the use of postoperative subconjunctival injections of 5-FU in 19 eyes of 19 patients was compared with a single intraoperative application of MMC in 20 eyes of 20 patients. All eyes were at high risk for failure of glaucoma filtering surgery. RESULTS Follow-up ranged from 26 to 38 months (mean, 32.0 months). Three eyes in the MMC-treated group and two eyes in the 5-FU-treated group required subsequent surgery to control the IOP. Excluding these patients, intraocular pressure (IOP) averaged 9.0 +/- 4.9 mmHg in the MMC-treated eyes versus 16.3 +/- 4.6 mmHg in the 5-FU-treated eyes at the patients last visit (P = 0.0003). Of the MMC-treated eyes, 81.3% had IOPs less than or equal to 12 mmHg compared with 26.7% of eyes in the 5-FU group (P = 0.0023). In the MMC-treated group, the average number of medications for IOP control at last visit was 0.5 +/- 0.8 compared with 1.6 +/- 1.3 in the 5-FU-treated group (P = 0.01). Late postoperative complications (those occurring more than 3 months after surgery) were similar for the two groups, with the exception of formation of a Tenon cyst in three of the eyes treated with MMC compared with none of the 5-FU-treated eyes. CONCLUSIONS Eyes treated with MMC have lower IOP on fewer medications than eyes treated with 5-FU. Late postoperative complications are similar with the exception of an increased incidence of Tenon cyst formation in the MMC-treated eyes.

Treatment of Neovascular Glaucoma with Transscleral Panretinal Cryotherapy

Transscleral panretinal cryotherapy was used to treat six eyes with neovascular glaucoma. The media of each involved eye were sufficiently cloudy at the time of treatment to prevent adequate panretinal photocoagulation. A checkerboard pattern of eight 2.5-mm cryotherapy applications was placed in each quadrant. Five of the eyes were also treated with 180 degrees of cyclocryotherapy. Within 72 hours of treatment, the intraocular pressure in each eye returned to a controllable level. The iris neovascularization in each eye regressed or totally disappeared within six weeks.

Effects of Pupillary Dilation on Automated Perimetry in Normal Patients

The effects of pupillary dilation (tropicamide 1%) on automated static threshold perimetry were studied in 18 normal subjects using the Humphrey field analyzer 30-2 and STATPAC programs. The mean defect worsened by 0.83 decibels (standard deviation, 0.92 decibels) in dilated fields as compared with baseline visual fields (P = 0.001). These findings indicate that pupillary dilation in healthy subjects who are not receiving ocular medications produces statistically significant declines in threshold sensitivities. Valid comparison of results from serial visual field testing, therefore, depends on control of or adjustment for the effect of pupillary dilation.

Prevalent Attitudes Regarding Residency Training in Ocular Anesthesia

PURPOSE To determine the current level of formal training in ocular anesthesia provided to nonophthalmologist physicians, the rationale for this training or lack thereof, and the perceived need for this training by anesthesia residency training programs. METHODS A two-page survey questionnaire was forwarded to all residency directors of ophthalmology and anesthesia training programs listed with the American Medical Association. A second mailing followed 2 months after the initial mailing if no response was received from a particular program. RESULTS An overwhelming response of 92% of ophthalmology programs and 76% of anesthesiology programs was achieved. In 93% of ophthalmology programs and 77% of anesthesiology programs, no formal training was provided to nonophthalmologist physicians in retrobulbar or peribulbar anesthesia. In addition, 78% of ophthalmology and 65% of anesthesiology programs denied having any plans to provide this training even though 40% of the anesthesia departments wanted to initiate and coordinate such training. CONCLUSIONS Currently, few ophthalmology programs offer formal training to anesthesiology residents in ocular anesthesia. Following are the predominant factors involved in this decision: (1) the operating surgeon is ultimately responsible for any complications; (2) there is a lack of knowledge of orbital anatomy and axial eye length by anesthesia personnel; and, most importantly, (3) there is a brief episodic nature in which anesthesia residents encounter ophthalmologic procedures resulting in minimal opportunities for training and experience from which the residency training program could ensure quality outcome and proper credentialling.

Premature Ventricular Systole Detection by Applanation Tonometry

We first identified (and probably stimulated) premature ventricular systoles in six patients while performing Goldmann applanation tonometry. One patient developed atrial fibrillation and one patient had a follow-up electrocardiogram showing increasing numbers of these extra systoles without any other abnormalities. Just as in tonography, these were detected during applanation tonometry as rapid decreases in intraocular pressures followed by a gradual return to prior levels. The decrease in measured intraocular pressure was occasionally 8 mm Hg but usually was between 2 and 5 mm Hg. These systoles probably occurred during the first part of applanation tonometry and during the first few office visits.