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Biomedical subjects

Orna Geyer

Publications and source records attributed to Orna Geyer.

18 recordsLinked to original sources
PubMed2006

The involvement of matrix metalloproteinases 2 and 9 in rat retinal ischemia.

BACKGROUND: The involvement of matrix metalloproteinases (MMPs) in ischemic tissue damage and remodeling has been reported by many investigators. Our study was designed to investigate the involvement of MMPs and of tissue inhibitors of metalloproteinases (TIMPs) in rat retinal ischemic injury, the effect of nitric oxide synthase (NOS) inhibitors on MMPs' activity in this model and whether minocycline (an MMP inhibitor) is protective in retinal ischemia. METHODS: Ninety-four rats were used in the study. Ischemia was induced by 90 min elevation of intraocular pressure. MMPs' activities and the effect of NOS inhibitors [aminoguanidine (AG) or N-nitro-L-arginine (NNA)] and minocycline on MMPs' activities were assessed by zymography and TIMPs expression by Western analysis. Morphological damage was quantified by morphometry of hematoxylin and eosin-stained retinal sections. RESULTS: Retinal extracts exhibited activities of proMMP-9 and proMMP-2. The activity of proMMP-9 increased immediately post ischemia (PI) and peaked to 4.6 times that of normal untreated controls in ischemic retinas and to 2.6 times that of controls in retinas of fellow sham-treated eyes at 24 h PI. The relative amount of TIMP-1 increased to 1.9-fold following ischemia and 2.5-fold in fellow sham-treated eyes at 24 h PI. ProMMP-2 activity increased more than two-fold immediately, at 24 h and at 48 h PI in ischemic retinas, and insignificantly in fellow sham-treated eyes. Treatment with 25 mg/kg AG or NNA caused a non-significant increase in proMMP-9 activity at 24 h PI (3.7- and 2.9-fold, respectively, p>0.6). There was no effect of AG or NNA on the activity of proMMP-2. Minocycline significantly attenuated the retinal ischemic damage, primarily by partially preserving ganglion cells and the inner plexiform layer. Minocyline (0.5 mg/ml or 5 mg/ml) inhibited MMPs' activities in ischemic retinal extracts in vitro. CONCLUSIONS: MMPs participated in morphological ischemic damage to rat retina. Treatment with minocycline dramatically attenuated damage to the retina.

Animals↗
PubMed2006

[Binocular function and patient satisfaction after monovision induced by laser in situ keratomileusis (lasik)].

INTRODUCTION: Presbyopia is a problem in refraction attributed to loss of near vision. Monovision (MV) is a strategy to compensate for presbyopia whereby one eye is corrected for distance and the other eye corrected for near vision. The patient should be able to suppress the blurred image from one eye and see clearly at all distances without glasses. PURPOSE: To measure binocular function and patient satisfaction with MV induced by laser in situ keratomileusis (LASIK) in myopic and hyperopic presbyopic patients. METHODS: Patients 39 years or older who underwent MV LASIK and minimum 90 days follow-up were included in the study. The following parameters were used: distance and near corrected/uncorrected visual acuity, manifest refraction before and after surgery and near stereopsis postoperatively. Patient satisfaction was evaluated by a questionnaire. RESULTS: One hundred and fourteen patients (100 myopes, 14 hyperopes) were included. After surgery, 79% had distance binocular uncorrected visual acuity of 6/7.5 or better and 97% of the patients had near binocular uncorrected visual acuity of J2 or better. The median of the near steroacuity was 100 seconds of arc. A total of 80% of the patients were very satisfied. The surgical score was 85. An overall 89.5% of the patients felt that their main goal had been achieved and 89% would choose to have surgery if they had it to do over. Eight percent of the patients used glasses for distance and 24% used reading glasses after surgery. The quality of life while driving at night improved in 55% and deteriorated in 15% of the patients. The quality of life while driving during the day improved in 69% and deteriorated in 1%. CONCLUSIONS: Monovision induced by LASIK may be a valuable option for both myopic and hyperopic presbyopic individuals considering refractive surgery. However, due to the risk of decreased night vision and continued use of reading glasses during the day, this surgery may not be suitable for patients in whom night driving and/or reading are an essential part of their life.

Humans↗
PubMed2005

Long-term intraocular pressure control after clear corneal phacoemulsification in glaucoma patients.

PURPOSE: To evaluate long-term IOP control after sutureless clear corneal phacoemulsification in eyes with preoperatively controlled glaucoma. SETTING: Institutional study. METHODS: The charts of 345 patients who had uneventful sutureless clear corneal phacoemulsification with acrylic foldable lens (IOL) implantation were retrospectively reviewed. Included were 58 patients with medically controlled open-angle glaucoma and 287 normal controls. Follow-up was 1 to 2 years. Outcome measures were postoperative IOP and number of glaucoma medications. RESULTS: Postoperatively, there was an insignificant decrease in IOP in the glaucoma group; the mean decrease was 1.5 mm Hg +/- 4.4 (SD) at 12 months and 1.9 +/- 4.9 mm Hg at 24 months. The mean number of medications decreased significantly at 12 months (0.53 +/- 0.86) and at 24 months (0.38 +/- 0.9) (P=.04). The control group also had a significant decrease in IOP, with a mean decrease of 0.72 +/- 3.7 mm Hg at 12 months (P=.01) and 1.33 +/- 3.2 mm Hg at 24 months (P<.0001). The decrease in IOP was more pronounced in eyes with a higher preoperative IOP in both the glaucoma and control groups. CONCLUSIONS: These findings suggest that sutureless clear corneal phacoemulsification with foldable acrylic IOL implantation is a relatively simple and efficient surgical option in patients with cataract and well-controlled glaucoma. The approach combines long-term IOP control with fewer medications and leads to rapid visual rehabilitation.

Acrylic Resins↗
PubMed2005

Intraoperative complications of phacoemulsification in eyes with and without pseudoexfoliation.

PURPOSE: To determine the intraoperative complications in a large series of phacoemulsification procedures, including patients with and without pseudoexfoliation, excluding those with marked phacodonesis or lens subluxation. SETTING: Department of Ophthalmology, Carmel Medical Centre, Haifa, Israel. METHODS: This institutional case-control study included 1501 consecutive phacoemulsification procedures: 137 eyes with pseudoexfoliation and 1364 eyes without this condition. Baseline demographics and clinical factors were collected from the medical files. A comparative analysis of the incidence of intraoperative complications in eyes with or without pseudoexfoliation was calculated. Univariate analysis and multiple logistic regression were used to identify ocular factors that predicted intraoperative complications. RESULTS: There was no significant difference (P>.05) in the rate of intraoperative complications between the pseudoexfoliation (5.8%) and control (4.0%) groups. There were no significant differences in the incidence of capsular breaks, vitreous loss, and zonular ruptures without vitreous loss in the 2 groups. Pseudoexfoliation did not confer a statistically higher risk for intraoperative complications (odds ratio 1.62, 95% confidence interval 0.74-3.55). CONCLUSION: Phacoemulsification by experienced surgeons is safe in eyes with pseudoexfoliation without marked phacodonesis or lens subluxation.

Aged↗
PubMed2005

[Eye injuries caused by rotating wire brushes].

BACKGROUND: Blunt or penetrating eye injuries are quite common in industry. Workers with high risk of eye trauma do not always wear safety goggles. AIM: This is a report on three patients with wire brush eye injury who presented in our department over a 4 month period. RESULTS: In all 3 cases, the wire brush penetrated the cornea, the iris and the lens. In one case, an endophthalmitis developed, and despite appropriate treatment (including surgeries), the final visual outcome was poor. CONCLUSIONS: Eye injuries from rotating wire brushes should be treated with caution, as there is a definite risk of developing endophthalmitis. Safety goggles are recommended for the prevention of such injuries.

Cornea↗
PubMed2005

Ophthalmic complications of dental anesthesia: three new cases.

Two patients had ipsilateral optic neuropathy and one patient had an ipsilateral abduction deficit and a dilated, poorly reactive pupil immediately after anesthesia of upper alveolar teeth. In one patient with optic neuropathy, the optic disc was not swollen, brain and orbit computed tomography (CT) was negative, and vision recovered completely within 2 weeks. In the other patient with optic neuropathy, the optic disc was swollen, brain and orbit CT were negative, and vision did not recover. In the patient with ductional and pupil deficits, recovery was complete within 24 hours. Since 1960, 39 cases of ophthalmic complications have been reported in the English literature. A majority have followed anesthesia of upper alveolar teeth. In all but three cases, the deficits were temporary. Diffusion, inadvertent needle penetration into the orbit, venous injection, or retrograde arterial injection is postulated as the mechanism by which the anesthetic agent reaches the cavernous sinus or orbit to cause the deficits.

Adult↗
PubMed2005

[Selective laser trabeculoplasty treatment for medication-refractory open angle glaucoma].

BACKGROUND: Selective laser trabeculoplasty (SLT) is a new method to reduce intraocular pressure in eyes with primary open angle glaucoma. The laser parameters are set to selectively target pigmented trabecular meshwork (TM) cells without damage to the adjacent non-pigmented tissue. PURPOSE: A clinical retrospective study was conducted to evaluate the 12 months results of SLT in the treatment of medically uncontrolled open angle glaucoma. PATIENTS AND METHODS: During the period March to September 2004, the authors performed a SLT in 50 patients (50 eyes) with open angle glaucoma uncontrolled on maximally tolerated medical therapy. Treatment was carried out with a frequency-doubled, Q-switched Nd:YAG laser 532 nm.(Selectra 7000 Laser Coherent, Inc., Palo Alto,CA). Approximately 85 to 90 non-overlapping laser spots were placed over 180 degrees of the trabecular meshwork at energy levels ranging from 0.6 to 1.4 mJ per pulse. In patients who required additional SLT therapy, the untreated 180 degrees was treated. During the follow-up period, patients were treated with antiglaucoma medications as required. The success rates were defined as decreases in intraocular pressure (IOP) of 3 mmHg or more with no additional medications, laser, or glaucoma surgery. RESULTS: The mean IOP reduction from baseline 6 months after treatment was 21% and 20% after 12 months. The success rates were 66% after 6 months and 55% after 12 months. Four eyes (8%) did not respond to SLT. One hour after SLT, an increase in IOP of more than 5 mm Hg was detected in 5 eyes (10%). Seven patients (14%) required additional SLT. CONCLUSIONS: SLT is efficient in lowering IOP in medication-refractory open angle glaucoma. It should be considered in such patients when surgery is contraindicated or refused.

Aged↗
PubMed2004

Adenylyl and guanylyl cyclase activity in the choroid.

The choroid, a low-resistance vascular structure provides nourishment to and removal of potential toxic waste products from the adjacent non-vascularized outer layers of the retina, macula, and optic disc region and may be involved in the pathology of normal tension glaucoma. This study is aimed at delineating the biochemical pharmacology of vascular tone control in this tissue. By using a procedure to harvest fresh choroidal tissue, we studied some basic characteristics of the adenylyl (AC) and guanylyl cyclase (GC) enzyme systems in this tissue using the 3H-cAMP/32P-ATP tracer method. Compared to respective baseline measurements (100+/-SEM%), AC activity was stimulated (p < 0.05) by forskolin (FSK, 477+/-59%), fluoroaluminate (AlF(4), 360+/-10.3%), isoproterenol (ISO, 129+/-5.5%), vasoactive intestinal peptide (VIP, 132+/-6.1%), calmodulin (CAM)+Mn2+ (196+/-69%), and dose-dependently by prostaglandin (PG) E2 (up to 162+/-3.6%). The antagonist drug calmidazolium inhibited the CAM-dependent increase but also blocked basal activity (47+/-2.0%) without affecting the FSK response. Other CAM blockers (TFP, W5) produced similar results but were not completely selective for CAM-activated cyclase. GDPbetaS, a blocker of G-protein coupling to AC did not affect AC responses to FSK, ISO, and AlF4, but decreased the response to PGE2. N-ethyl-carboxamido adenosine (NECA), which activates adenosine A2 receptors, did not synergize with FSK or add to ISO responses and did not activate AC by itself. In the GC system activity was stimulated (p< 0.05) by CAM+Mn2+ (239+/-27%), by atrial natriuretic peptide (ANP, up to 143+/-1.4%) and sodium nitroprusside (SNP, up to 179+/-1.6%). These results show that choroidal tissue has significant activities of the adenylyl and guanylyl cyclase second messenger systems potentially responsive to hormones/neurotransmitters that may control the degree of relaxation in this vascular tissue.

Adenylyl Cyclases↗
PubMed2004

Outcome of consecutive trabeculectomy.

PURPOSE: To establish a criterion for success of primary phakic trabeculectomy in the second eye of the same patient, using the first operated eye as a predictor for the surgical outcome. METHODS: The outcome of primary phakic trabeculectomy was retrospectively compared in both eyes of 23 patients. Sixteen patients were treated with antimetabolites and seven were not. Postoperative intraocular pressure and number of glaucoma medications in paired eyes of the same patients were compared. Surgical success was defined as postoperative IOP of <20 mmHg without medication. Bleb morphology and the number of glaucoma medications were also compared in both eyes. RESULTS: There was a positive correlation between the two eyes of a patient in the IOP values at each postoperative time point in both groups (with and without antimetabolites) (P > 0.05). At the last follow-up visit after trabeculectomy, the number of glaucoma medications used in paired eyes were not significantly different (P > 0.83). Surgical failure occurred more often in paired eyes than in single eyes. Bilateral failure occurred in 60% (3/5) of the failed trabeculectomies with antimetabolites and in 100% (3/3) of the failed trabeculectomies without antimetabolites. CONCLUSION: Trabeculectomy outcome in paired eyes of patients was similar in both antimetabolites treated and untreated eyes. Thus, trabeculectomy outcome in the first operated eye can predict the surgical result in the second eye of the same patient.

Adolescent↗
PubMed2003

Muscarinic blockers potentiate beta-adrenergic relaxation of bovine iris sphincter.

BACKGROUND: beta-Adrenergic relaxation of iris sphincter has been described in many species, including human. It is generally accepted that the size of the pupil is mainly controlled by muscarinic and alpha-adrenergic tonus. This study was undertaken to investigate the interactions between muscarinic and beta-adrenergic drugs in the relaxation of bovine iris sphincter. METHODS: Intact bovine iris sphincters were incubated in an organ bath and challenged with appropriate beta-adrenergic agonists and/or muscarinic antagonists. Tension was measured by a force transducer. RESULTS: Isolated bovine iris sphincter responded to muscarinic stimulation by contraction and to beta-adrenergic stimulation by relaxation. The beta-adrenergic agonists isoproterenol (ISO) and salbutamol (SAL) each caused marked relaxation of sphincters pre-contracted with the muscarinic agonist carbamylcholine. Sphincters pre-treated with the muscarinic antagonists atropine (0.1 micro M) or ipratropium bromide (10 micro M) and challenged 5 min later with either isoproterenol (0.3 nM) or salbutamol (10 nM) exhibited approximately twofold potentiation of beta-adrenergic relaxation. Adding the drugs in the reverse order did not produce any potentiation over the effect of beta-adrenergic stimulation alone. The dose-response curve to isoproterenol in naive sphincters or sphincters pre-treated with atropine indicated that muscarinic blockade decreased the EC(50) rather than potentiated maximal beta-adrenergic relaxation. CONCLUSION: Muscarinic antagonists potentiate beta-adrenergic relaxation of the sphincter by affecting the apparent potency of beta-adrenergic agonists and not by antagonizing the intrinsic tonus produced by endogenously released acetylcholine.

Adrenergic beta-Agonists↗
PubMed2003

The prevalence of glaucoma in patients with sleep apnea syndrome: same as in the general population.

PURPOSE: An association of glaucoma and sleep apnea syndrome (SAS) has been widely reported. We investigated the largest group of patients with SAS thus far to determine the prevalence of glaucoma among these patients. DESIGN: Cross-sectional study. METHODS: An institutional study. STUDY POPULATION: A total of 228 patients with SAS. OBSERVATION PROCEDURES: Sleep studies determined the respiratory disturbance index (RDI) during night sleep. Ocular examination included intraocular pressure (IOP) measurement, optic disk evaluation, and Humphrey visual field examination. MAIN OUTCOME MEASURES: The SAS was diagnosed as an RDI > 10. The RDI was graded to determine the severity of SAS: mild (RDI, 10-19), moderate (RDI, 20-39), and severe (RDI > 40). Open-angle glaucoma was diagnosed when a glaucomatous visual field defect matched the optic disk changes, irrespective of IOP levels. RESULTS: Nineteen participants had mild SAS (mean +/- standard deviation, RDI = 15 +/- 3), 129 had moderate SAS (RDI = 28 +/- 5), and 80 had severe SAS (RDI = 54 +/- 11). Open-angle glaucoma was found in five SAS subjects, a prevalence of 2% (95% confidence interval, 0.7% to 5%). There was no correlation between RDI and the presence of glaucoma (chi-square = 1.18; degrees of freedom = 2; P =.6) or between the RDI and the IOP (r = -0.067; P =.316). CONCLUSION: The prevalence of glaucoma in SAS patients was similar to that in the general Caucasian population.

Adult↗
PubMed2003

Stabilization of post-trabeculectomy flat anterior chamber with Healon and sulfur hexafluoride.

We present the management of 2 cases of post-trabeculectomy flat anterior chamber with hypotony due to an overflowing fistula. When separate attempts to reform the anterior chamber by intracameral injection of sulfur hexafluoride (SF(6)) and sodium hyaluronate 1.0% (Healon) failed, we injected SF(6) 100% with Healon into the anterior chamber. This stabilized the anterior chamber without compromising the integrity of the filtering bleb. No complications were observed. This simple, safe, and effective procedure offers another option for the management of a flat anterior chamber due to overfiltration.

Anterior Chamber↗
PubMed2003

[Diode laser cyclophotocoagulation in refractory glaucoma].

PURPOSE: To evaluate the effect of contact transscleral diode cyclophotocoagulation for refractory glaucoma. METHODS: Thirty-three patients with intractable glaucoma were treated with contact diode cyclophotocoagulation. Laser radiation (810-nm) was delivered to the eye by a fiberoptic (G-probe) placed 1.2 mm behind the limbus. Laser setting used was 2 W power for the duration of 2 seconds. Forty to 45 laser spots were applied over 360 degrees. Intraocular pressure (IOP), the number of glaucoma medications, visual acuity and complications were all assessed at last follow-up visit 12 months after laser treatment. Success was defined as IOP of less than 22 mmHg with medications at the last follow-up visit. RESULTS: The mean IOP decreased from 37.8 +/- 8.0 mmHg pre-diode treatment to 18.2 +/- 9.2 mmHg at last follow-up visit after treatment (p < 0.05). About 73% of patients achieved IOP of between 2 and 22 mmHg at final follow-up. The mean number of medications required decreased from 3.4 +/- 1.1 before to 2.4 +/- 1 after treatment (p < 0.05). Fifty five percent of the patients had a deterioration in visual acuity. Other complications were few and included transient hyphema, uveitis, choroidal detachment and hypotony. CONCLUSION: Contact transscleral diode cyclophotocoagulation is effective in lowering IOP and reducing the number of glaucoma medications in refractory glaucoma. The deterioration in visual acuity post-laser is a limitation of the treatment.

Aged↗
PubMedDate not supplied

Gender and age effects on pulsatile ocular blood flow.

PURPOSE: To examine gender and age effects on pulsatile ocular blood flow (POBF). METHODS: Normal subjects, 152 females and 107 males, were separated into younger (40-50) and older (50-60) age groups. RESULTS: For younger women, mean POBF (15.3 +/- 3.7 microl/s) was significantly different (p < 0.01) than for older women (13.8 +/- 3.5 microl/s), younger men (13.2 +/- 3.3 microl/s), and older men (13.3 +/- 3.1 microl/s). The mean POBFs for each of the latter three groups were not significantly different (p > 0.41) from one another. The four groups showed no significant differences in intraocular pressure (p > 0.07) or refraction (p > 0.46). Pulse rate for younger women was significantly higher (p < 0.05) than for the older two groups, but there were no significant pulse rate differences (p > 0.08) between other groups. POBF was not correlated with IOP (r2 < 0.04), refraction (r2 < 0.009) or pulse rate (r2 < 0.04). CONCLUSION: Gender and age play an important role in POBF.

Adult↗
PubMedDate not supplied

Iris prolapse at the surgical site: a late complication of nonpenetrating deep sclerectomy.

To investigate the occurrence and management of late-onset iris prolapse through the surgical wound after nonpenetrating deep sclerectomy. Two cases of iris prolapse that presented 8 and 10 months, respectively, after surgery for glaucoma were reviewed. One of the cases was associated with mild trauma. The postoperative follow-up was 5 and 24 months, respectively. The iris tissue bulge did not progress and there were no other complications. The visual acuity was not affected and the intraocular pressure was controlled with medical therapy. These cases demonstrate that the eye is weaker than normal at the surgical site after nonpenetrating deep sclerectomy, allowing iris protrusion. Iris prolapse should be added to the list of late postoperative complications of nonpenetrating deep sclerectomy.

Aged↗
PubMedDate not supplied

Nonpenetrating deep sclerectomy with the use of adjunctive mitomycin C.

BACKGROUND AND OBJECTIVE: To determine whether adjunctive use of mitomycin C (MMC) would increase the success rate of primary nonpenetrating deep sclerectomy with collagen implant. PATIENTS AND METHODS: Twenty-six patients (26 eyes) with primary open-angle glaucoma uncontrolled with maximally tolerated medical therapy were randomly assigned to undergo nonpenetrating deep sclerectomy and collagen implant, either with (13 eyes) or without (13 eyes) 0.3 mg/mL of adjunctive MMC for 3 minutes. Intraocular pressure (IOP), number of glaucoma medications, and visual acuity were assessed before and 12 and 24 months after surgery. RESULTS: The mean age of the study patients was similar in both groups (MMC = 68.1 +/- 8 years, control = 65.8 +/- 6.8 years). At the 12- and 24-month follow-up visits, the mean IOP with or without medications was lower in the MMC group than in the control group (15.6 +/- 3.5 vs 17.2 +/- 3.9 mm Hg at 12 months and 15.8 +/- 5.6 vs 17.8 +/- 2.8 mm Hg at 24 months, respectively). The IOP with or without medications significantly decreased after surgery in both groups (P < .05). Twelve months after surgery, the IOP decreased by 48% in the MMC group and by 35% in the control group. At the end of follow-up (24 months), the IOP decreased by 48% in the MMC group and by 32% in the control group (P = .01). The mean number of glaucoma medications decreased after surgery, there was no significant difference in complications (hyphema and suprachoroidal hemorrhage), and visual acuity was unchanged throughout the study in both groups. CONCLUSION: The use of MMC in nonpenetrating deep sclerectomy with collagen implant is safe and improves surgical results.

Aged↗