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Biomedical subjects

H D Hoskins

Publications and source records attributed to H D Hoskins.

17 recordsLinked to original sources

Holmium laser sclerostomy in glaucoma management: a new tool for an old procedure.

A THC: YAG laser (thulium, holmium, chromium doped YAG crystal) was used to create thermal sclerostomies in 49 glaucomatous eyes of 46 patients. The laser is a long-pulsed (300 microseconds), 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 tot 120 mJ were used with a repetition rate of 5 pulses/sec. Total energy levels to produce full-thickness sclerostomies ranged from 1.4 to 7.2 J. Subconjunctival 5-fluorouracil injections were administered in 46 eyes. Estimated probability of success was 74% at 6 months and 67% at 12 months. Mean intraocular pressure of successful cases was 13.3 mmHg at both both 6 months & 12 months. Twelve cases failed within the initial 6 months, and two additional cases failed by 12 months.

Follow-Up Studies

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.

Animals

Trabeculodialysis for inflammatory glaucoma: a review of 25 cases.

We reviewed the results following trabeculodialysis in 25 eyes of 22 patients with secondary glaucoma due to chronic anterior uveitis. After 1 year, intraocular pressure (IOP) was uncontrolled (greater than 21 mm Hg) in 11 eyes (44%). Trabeculodialysis controlled IOP (less than 21 mm Hg) in 14 eyes (56%), with an average follow up of 52 months (range, 12 to 151 months). Sixteen eyes (64%) were aphakic, but did no worse than the phakic eyes. One eye developed a subchoroidal hemorrhage 3 days postoperatively which required drainage. No other serious complications were encountered. Trabeculodialysis is a safe procedure which can achieve pressure control in these difficult eyes.

Aphakia

A 3-month comparison of 1% and 2% carteolol and 0.5% timolol in open-angle glaucoma.

Carteolol, a nonselective beta-adrenergic antagonist with intrinsic sympathomimetic activity, was compared in 1% and 2% topical solutions with 0.5% timolol in 105 patients with primary open-angle glaucoma. In this double-masked, randomized 3-month trial, all three preparations significantly lowered intraocular pressure throughout the study, with no significant differences being observed. There were also no significant differences among the three preparations with regard to ocular or systemic adverse reactions, including heart rate and blood pressure.

Administration, Topical

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.

Adult

The effect of a glaucoma medication reminder cap on patient compliance and intraocular pressure.

A multi-site, open-labeled clinical trial was conducted to evaluate the ease of use and acceptance of a newly developed medication cap with a memory aid (C Cap Compliance Cap, Allergan, Inc.) and its effect on patient compliance and intraocular pressure. One-hundred-twenty-two patients with glaucoma or ocular hypertension received their prescribed eye drops in bottles with the compliance cap. Overall, 83% of the patients found the compliance cap very easy to use. By the end of the study, significantly more patients (67%) claimed 100% compliance than prior to using the compliance cap (41%). An overall drop in intraocular pressure of 0.8 mm Hg was seen. However, in a subset of patients who reported an increase in compliance, mean intraocular pressure decreased from baseline by 1.7 mm Hg. The results of this study suggest that the compliance cap helps patients with glaucoma or ocular hypertension remember to take their medication as prescribed.

Adolescent

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.

Animals

Analysis of surgical and medical management of glaucoma in Sturge-Weber syndrome.

Management of glaucoma associated with Sturge-Weber syndrome (SWS) is difficult. The authors reviewed 36 eyes of 30 SWS patients with either early or late-onset glaucoma with a mean follow-up of 122 months (range, 24-253 months). Intervals between required surgical or medical interventions were analyzed. Intervention was attributed to elevated intraocular pressure (IOP) in 55% of cases and disc change in 45%. Median stable postoperative interval with goniotomy was 12 months; with trabeculotomy, 21 months; with trabeculectomy, 34 months; with argon laser trabeculoplasty, 25 months; and with medications, 57 months. Survival analysis shows statistically significant differences between goniotomy and medications. Intraoperative choroidal expansions developed in 24% of cases receiving a trabeculectomy, and none developed with either goniotomy or trabeculotomy.

Adolescent

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.

Animals

[Argon laser treatment of filtering bleb insufficiency].

The present paper reports on experience with a new contact lens which enables monophilic fixation sutures of the scleral flap to be severed transconjunctivally using highly focussed argon laser beams. The procedure is used in the early postoperative period on patients with failing filtering blebs. Indications and the procedures itself are described in detail.

Contact Lenses

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.

Aged

Adverse effects experienced by patients taking timolol.

Adverse effects involving one or more organ systems occurred in 38 of 165 patients with various types of glaucoma when timolol was added to their glaucoma therapy. It was necessary to discontinue timolol because of these side effects in 15 (9%) of the patients. Double-masked studies will be necessary to clarify the relationship of these adverse effects to the use of timolol.

Aged

Ciliary block (malignant) glaucoma.

A review of the history, recognition, mechanisms, and therapy of ciliary block glaucoma has been given. Cycloplegic therapy is stressed in the susceptible eye.

Choroid

Optic disk topography and visual field defects in patients with increased intraocular pressure.

One hundred one eyes of 54 ocular hypertensive patients were studied to determine the value of optic disk evaluation in predicting the presence or absence and the location and type of visual field defects by means of binocular slit-lamp examination and projected 35-mm monocular color slides. We suspected visual field loss erroneously in only one patient, and failed to detect ten (16%) of 61 eyes with field defects. An examiner experienced in slit-lamp evaluation of the optic disk can accurately predict the presence, absence, and location of field defects in most cases by stereoscopic evaluation of disk topography.

Adult

Operative complications of goniotomy.

During 320 anesthesias, 401 goniotomies were performed and are here reviewed. Significant complications were cardiopulmonary arrest (1.8%) and postoperative hemorrhage (0.5%). Useful vision was lost in one case (0.2%). No complications could be attributed to operating on both eyes during the same anesthesia. The authors believe that both eyes should be operated on during the same anesthesia when bilateral goniotomy is indicated.

Glaucoma