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Biomedical subjects

H V Gimbel

Publications and source records attributed to H V Gimbel.

At least 19 recordsLinked to original sources
PubMed1997

Excimer laser photorefractive keratectomy for residual myopia after radial keratotomy.

OBJECTIVE: To evaluate the surgical outcome of excimer laser photorefractive keratectomy (PRK) for undercorrected myopia after radial keratotomy (RK). DESIGN: Case series. SETTING: Gimbel Eye Centre, Calgary. PATIENTS: Thirty-one patients (37 eyes) who underwent excimer laser PRK for residual myopia after RK and were followed for at least 12 months. OUTCOME MEASURES: Spherical equivalent refraction, uncorrected and best corrected Snellen visual acuity, attempted and achieved correction, and corneal haze. RESULTS: The mean refraction before PRK was -3.11 (standard deviation [SD] 1.48) dioptres and 12 months after PRK, -1.18 D (SD 1.48 D) (p < 0.0001). Twelve months after PRK 24 eyes (64.9%) had an uncorrected visual acuity of 20/40 or better. Five eyes lost one line of best corrected acuity, and one eye lost more than two lines. At 12 months 28 eyes (75.7%) had no corneal haze or trace haze, 8 (21.6%) had mild haze, and 1 (2.7%) had marked haze. CONCLUSIONS: Our results indicate that excimer laser PRK has the potential to manage undercorrection of myopia after RK. The issues of refractive predictability, loss of best corrected visual acuity and corneal haze require further study.

Adult↗
PubMed1997

Management of zonular dialysis in phacoemulsification and IOL implantation using the capsular tension ring.

BACKGROUND AND OBJECTIVES: Cataract surgery with zonular dialysis remains a challenge for surgeons performing phacoemulsification and posterior chamber intraocular lens implantation. In this article, the authors report the results of cataract surgery with zonular dialysis that was managed with the capsular tension ring. PATIENTS AND METHODS: Of the 14 cataract surgery cases with loose or broken zonules managed with capsular tension rings that were retrospectively reviewed, 5 selected cases are presented in this article. RESULTS: The authors found that the capsular tension ring helps to avoid capsular collapse and vitreous presentation during surgery and maintains the circular contour of the capsular bag, allowing the intraocular lens to easily be placed into the bag. There was no observable decentration of the intraocular lens after surgery. CONCLUSION: The capsular tension ring may provide an alternative means to manage zonular dialysis during phacoemulsification and posterior chamber intraocular lens implantation.

Aged↗
PubMed1996

Posterior capsulorhexis with optic capture in pediatric cataract and intraocular lens surgery.

BACKGROUND: A major concern in pediatric intraocular lens implantation surgery is the high incidence of posterior capsule opacification. The purpose of this article is to investigate a surgical technique for maintaining a clear visual axis after pediatric cataract and intraocular lens surgery. METHODS: In a prospective evaluation, posterior capsulorhexis with optic capture as a surgical technique for preventing secondary membrane formation after pediatric cataract extraction is investigated. This technique involves capture of an intraocular lens optic through a posterior curvilinear capsulorhexis opening. Perioperative complications and incidence of secondary cataract are presented. Results will be compared to an historic cohort of patients with pediatric cataract-intraocular lens who did not have posterior continuous curvilinear capsulorhexis with optic capture. RESULTS: In 13 consecutive eyes operated on in children aged 2 to 12 years (mean, 5.8 years), there was no opacification of the visual axis at a mean follow-up of 19 months after surgery (range, 8-30 years). CONCLUSION: Posterior capsulorhexis with optic capture holds promise as a technique for preventing secondary membrane formation. This maneuver ensures centration of the posterior chamber intraocular lens while eliminating the need for an anterior vitrectomy. Apposition of the anterior and posterior capsule leaflets anterior to the optic may limit the migration of Elschnig pearls, reducing the incidence of secondary membranes and the need for additional procedures.

Cataract↗
PubMed1996

Experience during the learning curve of laser in situ keratomileusis.

PURPOSE: To identify pitfalls and offer hints on achieving a successful outcome during the early laser in situ keratomileusis (LASIK) learning process. SETTING: Gimbel Eye Centre, Calgary, Alberta, Canada. METHODS: This was a retrospective review of the preoperative planning, surgical procedure, intraoperative and postoperative problems, and early postoperative anatomic and refractive results in the first 73 eyes that had LASIK. RESULTS: Intraoperative complications included failure of the keratome to make a cut, excessively thin cap, repositioning difficulty, and inadequate intraocular pressure elevation. Early postoperative complications included excessive central and peripheral wrinkling of the cap, peripheral lipid deposits, and central edema of the cap. One month postoperatively, mean spherical equivalent refraction was -0.90 diopters (D) (range +1.75 to -6.00 D), and 45 eyes had a best corrected visual acuity between 20/15 and 20/40. CONCLUSION: Our retrospective review of the problems experienced during the early LASIK learning process should help novice lamellar refractive surgeons avoid such problems and shorten the learning curve.

Adult↗
PubMed1996

Effect of pharmacological dilation and constriction of pupil on corneal topography.

A prospective study was undertaken to investigate the effect of pharmacological pupillary dilation and constriction on corneal topography. Corneal topography was performed using the EyeSys system on 28 normal subjects before and after pupil dilation, constriction, and then with the pupil intact (no medication). Our results show that both flattening and steepening of the corneal curvature were found in all three examination periods. The numbers of corneas with flattening and steepening in each examination period were compared and found not to be statistically different. Mean change of corneal flattening was compared with mean change of corneal steepening in each examination period and again no significant difference was found. These results indicate that the slight changes in corneal power and radius following pharmacological pupillary dilation or constriction may be due to either the inability to repeat by the subjects, or error by observers or instrument.

Adult↗
PubMed1996

Anterior chamber fluid cultures following phacoemulsification and posterior chamber lens implantation.

BACKGROUND AND OBJECTIVE: A randomized, prospective study was undertaken to evaluate the incidence of positive cultures in the anterior chamber following cataract surgery when using intracameral gentamicin compared with no antibiotic. PATIENTS AND METHODS: A total of 97 patients were enrolled-- 48 receiving gentamicin in the irrigating solution and 49 receiving no intracameral antibiotics (control group). Each cataract extraction was accomplished by phacoemulsification followed by intraocular lens implantation. At the end of surgery, o.1 ml of anterior chamber fluid from each case was collected and cultured. RESULTS: All cultures were negative in the group receiving gentamicin. However, one positive culture occurred in the control group. There was no significant difference in the positive culture rate between the two groups (P = .52). CONCLUSION: This study suggests that cataract extraction with phacoemulsification and intraocular lens implantation has greatly reduced the incidence of bacterial contamination of anterior chamber fluid, with or without the use of intracameral antibiotic.

Anterior Chamber↗
PubMed1996

Effect of commercial dilating agents on laser flare-cell measurements.

OBJECTIVE: To compare the effect of tropicamide alone and tropicamide-phenylephrine on anterior chamber flare and cell measurements obtained with a laser flare-cell meter. DESIGN: Prospective study. SETTING: Gimbel Eye Centre, Calgary. SUBJECTS: Twenty white subjects (10 with blue irides and 10 with brown irides) aged 24 to 45 (mean 30.2) years without any known systemic or ocular disease. INTERVENTIONS: Laser flare-cell measurements were obtained 30 minutes after pupillary dilation with 1% tropicamide in one eye and a combination drop of 0.8% tropicamide and 5% phenylephrine in the other eye. The average of five readings was taken for each eye. OUTCOME MEASURES: Flare and cell measurements. RESULTS: There was no statistically significant difference in flare photon count or cell count between the eyes dilated with tropicamide and those dilated with tropicamide-phenylephrine. In addition, iris colour was not found to have a significant effect on flare and cell measurements. CONCLUSIONS: Our results suggest that pupillary dilation for laser flare-cell measurements can be done with either mydriatic agent in healthy white subjects of any eye colour without significant effects on the measurements. Further study is needed to determine whether the same is true in older subjects.

Administration, Topical↗
PubMed1995

Phaco sweep.

We present a variation on a technique for down slope sculpting designed to enhance the safety of sculpting deeply in the central nucleus. The phaco tip moves laterally to remove very deep nuclear material, increasing visualization with less risk of occlusion and break through to the capsule.

Humans↗
PubMed1995

Recognition and management of internal wound gape.

We describe a method for recognizing and managing wound gape of the internal aspect of a scleral tunnel incision. The apposition of the cataract internal incision can be adequately assessed with the use of a gonioprism during and after surgery. With self-sealing tunnel incisions, even though the external incision may be well sealed either with or without the use of a suture, the internal incision may be inconspicuously gaping. When an internal incision gapes open, it takes on the appearance of an elongated oval opening by gonioscopy, a process we have termed fishmouthing. Often fishmouthing can be closed by rapidly deepening the anterior chamber with balanced salt solution through the paracentesis incision; if this is unsuccessful, a limbal suture may be required. Assessment of the internal incision with a gonioprism and management of internal incision fishmouthing is an important method to ensure wound stability and minimize surgically induced astigmatism.

Anterior Chamber↗
PubMed1995

Intraocular pressure response to combined phacoemulsification and trabeculotomy ab externo versus phacoemulsification alone in primary open-angle glaucoma.

We investigated trabeculotomy ab externo as a means of optimizing intraocular pressure (IOP) control in glaucoma patients having phacoemulsification and implantation of an intraocular lens (IOL). A prospective, randomized, controlled study was performed to evaluate the effect on IOP and the incidence of complications associated with combined phacoemulsification and trabeculotomy ab externo. The study group had the combined procedure, while the control group had only phacoemulsification with IOL implantation. A total of 106 patients were randomized, and the IOP for each group was compared at 3, 6, 12, and 24 months. At two years, the mean IOP reduction was 6.1 mm Hg in the study group and 3.8 mm Hg in the control group (P = .001). There were no complications in the control group. Two complications (2/53 or 3.8%) occurred in the study group: a small tear in Descemet's membrane and a postoperative microhyphema. There was no increase in medication in either the study or control group. Combined phacoemulsification and trabeculotomy ab externo represents an option to lower IOP and potentially reduce the need for pressure-lowering medications in patients with primary open-angle glaucoma and visually significant cataracts.

Aged↗
PubMed1994

Posterior capsulorhexis with optic capture: maintaining a clear visual axis after pediatric cataract surgery.

We describe a technique for preventing secondary membrane formation after pediatric cataract extraction. This technique involves capture of an intraocular lens (IOL) optic through a posterior curvilinear capsulorhexis opening in an attempt to maintain a clear visual axis in children after cataract surgery. This maneuver ensures centration of the posterior chamber IOL because the haptics remain in the capsular bag and the optic is captured in the posterior capsular opening. Also, the need for an anterior vitrectomy may be eliminated. Apposition of the anterior and posterior capsule leaflets anterior to the optic may limit the migration of Elschnig pearls, reducing the incidence of secondary membranes and the need for additional procedures.

Cataract↗
PubMed1994

Aqueous flare increase after light exposure in age-related macular degeneration.

An increase in anterior chamber flare is associated with many ocular conditions, including retinal diseases. We assessed anterior chamber flare in 18 patients (19 eyes) with exudative age-related macular degeneration using the Kowa flare-cell meter immediately before and 1 hour after exposure to 40 light flashes at a flash intensity of 300 W/s delivered with a Topcon fundus camera. Fourteen eyes showed a significant increase in flare 1 hour after light exposure (T = -3.452, p < 0.003, t-test). A second measurement in a subgroup of 10 patients exposed to 40 light flashes at a flash intensity of 36 W/s showed no significant change in flare 1 hour after light exposure. Multiple analysis of variance (two-way interaction) showed a highly significant difference between the two groups (F[1,27] = 8.66, p < 0.0066). We discuss possible mechanisms that may have produced these changes as well as implications of light exposure in various diagnostic and therapeutic settings.

Aqueous Humor↗