The role of diversity in the health care needs of California.

Socioeconomic, racial, and ethic diversity influence many facets of health care, including access to health services, the morbidity and mortality of disease, and the process of training health care professionals. California has an increasingly diverse population, and it is essential that the University of California medical schools carefully address the role of diversity in medical education and in education for the many other professionals who have a key role in the provision of care and services to Californians. In this paper, we provide evidence in support of the belief that the University of California system must train a physician workforce that reflects the racial, ethnic, and socioeconomic characteristics of California's population in order to provide equitable health care to all segments of the state's people.

Update on the subconjunctival THC:YAG (holmium) laser sclerostomy Ab externo clinical trial: a 4-year report.

BACKGROUND AND OBJECTIVE: This is a follow-up report on 103 THC:YAG (holmium) sclerostomies ab externo performed on 87 eyes of 81 patients. PATIENTS AND METHODS: The patients received pulse energies of 0.06 to 0.13 J (mean total energy 4.4 +/- 3.3 J, range 0.6 to 17.1 J). RESULTS: The estimated success rates with or without medication, and allowing a second procedure, were 44% at 2 years and 36% at 4 years. The mean preoperative intraocular pressure (IOP) was 29.7 +/- 11.4 mm Hg, and the mean postoperative IOP in the successful patients was 13.6 +/- 4.6 mm Hg (P < .01). Hypotony and iris incarceration were the most frequent early complications. CONCLUSIONS: Although holmium laser sclerostomy is a relatively straightforward procedure and offers some advantages over standard trabeculectomy in select cases, it currently has a number of drawbacks that limit its use.

Update of the subconjunctival THC:YAG (holmium) laser sclerostomy ab externo clinical trial: 30-month report.

A THC:YAG laser (thulium, holmium, chromium-doped YAG crystal) was used to create 93 thermal sclerostomies ab externo in 81 glaucomatous eyes of 76 patients. Pulse energies of 80 to 120 mJ were used, with a repetition rate of 5 pulses per second. Total energy levels to produce full-thickness sclerostomies ranged from 1.4 to 7.2 J. Estimated probability of success was 0.66 at 12 months and 0.57 up to 30 months. The mean intraocular pressure in the successful cases was 12.8 +/- 4.0 mm Hg.

Subconjunctival THC:YAG ("holmium") laser thermal sclerostomy ab externo. A one-year report.

BACKGROUND: Laser sclerostomy can be performed in a less-invasive manner than standard filtering surgery. Longer wavelengths in the infrared range have water-absorptive characteristics that facilitate perforation of the sclera. The goal was to perform laser sclerostomy ab externo to avoid intraocular instrumentation and minimize conjunctival trauma. METHODS: A thulium, holmium, chromium-doped:YAG (THC:YAG) crystal laser was used to create thermal sclerostomies in 49 glaucomatous eyes of 46 patients. The laser is a long-pulsed (300-microsecond), compact, self-contained, solid-state laser operating in the near infrared (2.1 microns). Energy was delivered via a specially designed 22-gauge (712-microns) optic probe that emits energy at a right angle to the long axis of the fiber. Pulse energies of 80 to 120 mJ were used. Total energy levels to produce full-thickness sclerostomies ranged from 1.4 to 7.2 J. Subconjunctival 5-fluorouracil (5-FU) injections were administered in 46 eyes. Success was defined as an intraocular pressure (IOP) of less than or equal to 22 mmHg with or without medications. For eyes in which preoperative IOP was less than or equal to 22 mmHg, success was defined as a decrease in IOP of greater than or equal to 30%. RESULTS: Estimated probability of success allowing for one retreatment was 0.75 at 6 months and 0.68 at 12 months. Mean IOP of successful cases was 13.3 mmHg at both 6 and 12 months. Twelve cases failed within the initial 6 months, and two additional cases failed by 12 months. CONCLUSION: THC:YAG ("holmium") laser thermal sclerostomy is an alternative to other full-thickness filtration procedures. Further evaluation and understanding will define its ultimate role in glaucoma management.

Levobunolol compared to dipivefrin in African American patients with open angle glaucoma.

The prevalence of open angle glaucoma is disproportionately high in the African American population. Information about the effectiveness of anti-glaucoma medications in an exclusively African American population is lacking. We treated both eyes of 38 African American patients who have stable open angle glaucoma with either levobunolol b.i.d. or dipivefrin b.i.d. to evaluate the effectiveness of each drug in lowering intraocular pressure. Patients were treated for six weeks following a two week washout period. We measured intraocular pressure levels after one, three, and six weeks. Each medication produced a statistically significant decrease in intraocular pressure by week one. The mean pre-treatment pressure of 24.4 mmHg in the levobunolol was reduced to 17.0 mmHg by week six. The mean pre-treatment pressure of 25.4 mmHg in the dipivefrin treated group was reduced to 18.2 mmHg by week six. There was not a statistically significant difference in the pre-treatment or the final pressure between the two groups. Both levobunolol and dipivefrin produce a statistically significant decrease in intraocular pressure in African American patients with open angle glaucoma.

Filtering seton implant for glaucoma: initial animal trial.

A newly developed silicone filtering seton device was implanted in each of five eyes of four rhesus monkeys after they had undergone extensive argon-laser trabeculoplasty to raise their intraocular pressure (IOP). One animal (one implant eye) was killed at 6 weeks. The other three animals (four implant eyes) were observed for 17 to 24 months following implantation surgery. Mild to moderate postoperative inflammation subsided during the first postoperative week. The eyes remained quiet throughout the remainder of follow up. The postoperative IOPs varied between 18% and 70% of the IOPs at the time of implant surgery. In the three monkeys that had unilateral surgery, the IOP at the final follow-up measurement was equal to or lower than the IOP in the unoperated fellow eye. In the monkey that had bilateral surgery, both of the final IOPs were lower than the preoperative ones.

Subconjunctival THC:YAG laser thermal sclerostomy.

A THC:YAG laser (thulium, holmium, chromium-doped YAG crystal) was used to create thermal sclerostomies in 21 glaucomatous eyes of 19 patients. The laser is a long-pulsed (300 microsec), compact, self-contained, solid state laser operating in the near infrared (2.1 mu). A 1-mm conjunctival stab incision was made 12 mm away from the sclerostomy site to allow entry of a specially designed 22-gauge (712 mu) optic probe that delivers energy at a right angle to the long axis of the fiber. Probe insertion produced minimal disturbance of the conjunctiva. Pulse energies of 80 mJ to 120 mJ were used with a repetition rate of 5 pulses/second. Total energy levels to produce full-thickness sclerostomies ranged from 1.4 to 4.8 J. Subconjunctival 5-fluorouracil injections were administered in 15 eyes. At 3 months the mean intraocular pressure of successful cases (16) was 14 mmHg (range, 9 to 22 mmHg). Of successful cases, the mean intraocular pressure at 6 months was 13 mmHg (range, 2 to 22 mmHg). Five cases failed within the initial 3 months, and 3 additional cases failed by 6 months. The authors conclude that this full-thickness sclerostomy technique may simplify filtering surgery without anterior chamber instrumentation and with minimal conjunctival trauma.

A new contact neodymium:YAG laser for cyclophotocoagulation.

A newly developed compact (40 kg), self-contained contact Neodymium:YAG laser produces high-peak, high-energy (800 mJ/pulse), short (1.0 millisecond) pulses with 1 to 3 pulses/exposure. Energy is delivered via a 320-microns cleaved quartz fiber optic probe. Cyclophotocoagulation was performed in five eyes of three medium-sized Dutch-pigmented rabbits. The eyes received exposures of 1 to 3 pulses/exposure. Energy delivered ranged from 100 to 800 mJ/pulse. Histopathology revealed ciliary body disruption and hemorrhage with no damage to overlying sclera. When used for transscleral cyclodiathermy in the rabbit, the laser created significant ciliary body disruption with minimal scleral injury.

Time course of thymoxamine reversal of phenylephrine-induced mydriasis.

We conducted a randomized, double-masked, paired comparison of 0.1% thymoxamine vs placebo for the reversal of phenylephrine-induced mydriasis. Mydriasis was induced with 2.5% phenylephrine in each eye of 74 subjects (148 eyes). Each subject then received 0.1% thymoxamine in one eye and placebo in the other eye. Pupillary measurements were obtained at regular intervals during the ensuing 8 hours. At all intervals, a greater percentage of thymoxamine-treated eyes returned to baseline pupillary diameters compared with placebo-treated eyes (P less than or equal to .01). For subjects in whom both pupils returned to baseline, thymoxamine-treated eyes returned to baseline in a mean of 2.2 hours, vs 5.2 hours for placebo (P less than .0001). Among thymoxamine-treated eyes, those with light irides responded more rapidly than those with dark irides, returning to baseline in 1.6 vs 2.8 hours, respectively (P = .0046). After constriction to baseline pupillary diameter had been achieved, no patients experienced a rebound dilation.

Subconjunctival THC: YAG laser limbal sclerostomy Ab externo in the rabbit.

A chromium-sensitized, and thulium and holmium-doped YAG laser (THC:YAG laser) was used to create bilateral limbal sclerostomies in six Dutch pigmented rabbits. The laser is a long-pulsed (300 microseconds) [corrected], compact, self-contained, solid-state laser operating in the near infrared (2.1 microns). A 1-mm conjunctival stab incision was made 12 mm away from the sclerostomy site to allow entry of a specially designed 26-gauge (480 microns) optic probe that delivers energy at right angles to the long axis of the fiber. Probe insertion minimally disturbed the conjunctiva. Pulse energies of 60 to 150 mJ were used with a repetition rate of 5 pulses/s. Energy levels ranging from 1.35 to 6.6 J produced full-thickness sclerostomies. Histopathology showed a sharply defined perforating limbal wound at all energy levels. The overlying conjunctiva was intact, with swelling of the adjacent cornea. A peripheral iridectomy was intentionally created with the laser through the peripheral limbus, resulting in a sharply defined perforating tract through the iris/ciliary body. This technique may simplify filtering sclerostomy surgery, without anterior chamber instrumentation and with minimal conjunctival trauma.

Confidence intervals for change in automated visual fields.

Three successive fields of 136 eyes (86 patients) were extracted from our data base containing over 3000 visual fields performed on the Humphrey visual field analyser with program 30-2. Series of fields in which the second field was depressed relative to the first were selected for analysis to determine how much change between the first two fields was required to predict a downward trend as confirmed by the third field in the series. The data were stratified with respect to initial field damage. Seven regions of the visual field were analysed including the upper and lower temporal and nasal quadrants, the superior and inferior Bjerrum regions, and the whole field. Minimally damaged regions required between 4.7 and 5.6 dB change in mean sensitivity, whereas more damaged regions required between 5.5 and 7.2 dB change in mean sensitivity to have 95% confidence that the negative trend would be confirmed by the third field. The superior Bjerrum region was the most sensitive for the detection of change, and the lower temporal region was the least sensitive. We conclude from this series of data that large changes between two successive fields are required to be sure that the changes are due to disease rather than chance fluctuation. Where any doubt exists, the field should be repeated to confirm the reality of change.

Neodymium:YAG laser iridotomy.

During the past several years the Neodymium:YAG laser has become increasingly popular for performing peripheral iridotomy. Using energy levels of 2-8 millijoules per shot and 1-3 shots per treatment, most irides can be penetrated in one sitting. Nd:YAG laser iridotomies show very little tendency to close, except in patients with active intraocular inflammation. A small amount of hemorrhage is common following YAG laser iridotomy, but clinically significant hyphema is rare. Significant lenticular or corneal damage is extremely rare. Although longterm follow-up of large numbers of patients is lacking, Nd:YAG laser iridotomy appears to be a safe and effective alternative to Argon laser iridotomy in selected patients.

Isopilocarpine binding to muscarinic cholinergic receptors.

Isopilocarpine coexists with pilocarpine in nature, and it is present in varying degrees in commercial pilocarpine preparations. Using muscarinic cholinergic receptors from bovine ciliary muscle tissue, we measured the relative binding affinity of isopilocarpine and pilocarpine. The binding affinity of isopilocarpine was approximately one-tenth that of pilocarpine. Because of the relatively low concentration of isopilocarpine found in commercial pilocarpine preparations, and the low binding affinity of isopilocarpine for the muscarinic receptors, the practical effect of isopilocarpine contamination is small.

Flurbiprofen pretreatment in argon laser trabeculoplasty for primary open-angle glaucoma.

We examined the influence of topically administered flurbiprofen sodium 0.03%, a potent prostaglandin inhibitor, on the inflammatory response and intraocular pressure following argon laser trabeculoplasty. Our investigation included one eye of each of 118 patients with primary open-angle glaucoma in whom laser trabeculoplasty was indicated. Sixty-three patients received flurbiprofen and 55 received a vehicle during the two-hour period immediately preceding laser therapy and for one week postoperatively. No significant differences in postoperative IOPs were noted between groups. However, when we considered conjunctival erythema at 24 hours or control of inflammation at the termination of the investigation, the eyes receiving flurbiprofen had less inflammation than did the vehicle-treated eyes.

Measurement of pilocarpine and its degradation products by high-performance liquid chromatography.

An assay method for pilocarpine using reversed-phase high-performance liquid chromatography is presented. This method also measures isopilocarpine, the stereoisomer of pilocarpine, and the degradation products pilocarpic acid and isopilocarpic acid. Maximum sensitivity was obtained with optical absorbance at 216 nm.