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Biomedical subjects

V P Costa

Publications and source records attributed to V P Costa.

At least 19 recordsLinked to original sources
PubMed2006

The effects of prostaglandin analogues on the blood aqueous barrier and corneal thickness of phakic patients with primary open-angle glaucoma and ocular hypertension.

PURPOSE: To evaluate the effects of topical latanoprost, travoprost, and bimatoprost on the blood-aqueous barrier and central corneal thickness (CCT) of patients with primary open-angle glaucoma (POAG) and ocular hypertension (OHT). DESIGN: Prospective, randomized, masked-observer, crossover clinical trial. METHODS: A total of 34 phakic patients with POAG or OHT with no previous history of intraocular surgery or uveitis completed the study. Patients were randomized to use latanoprost 0.005%, travoprost 0.004%, or bimatoprost 0.03% once daily (2000 hours) for 1 month, followed by a washout period of 4 weeks between each drug. Aqueous flare was measured with a laser flare metre. CCT was calculated as the average of five measurements using ultrasound pachymetry. All measurements were performed by a masked observer (1000 h). RESULTS: There were no statistically significant differences between baseline mean IOP, mean CCT, and mean flare values among the groups. There was no statistically significant increase in mean flare values from baseline in all groups (P>0.05). There were no statistically significant differences between mean flare values among the groups (P>0.05). All medications significantly reduced the mean IOP from baseline (P<0.0001). IOP reduction obtained with travoprost (7.3+/-3.8 mmHg) was significantly higher than that obtained with latanoprost (4.7+/-4.2 mmHg) (P=0.01). A statistically significant reduction in mean CCT (0.6+/-1.3%) from baseline was observed when patients instilled bimatoprost (P=0.01). CONCLUSIONS: Latanoprost, travoprost, and bimatoprost had no statistically significant effect on the blood-aqueous barrier of phakic patients with POAG or OHT. Bimatoprost may be associated with a clinically irrelevant reduction in mean CCT.

Adult↗
PubMed2006

Long-term intraocular pressure control of eyes that developed encapsulated blebs following trabeculectomy.

PURPOSE: To evaluate the long-term intraocular pressure (IOP) control of eyes that developed an encapsulated bleb (EB) following trabeculectomy. METHODS: Between 1994 and 1995, 25 eyes developed EBs and were randomized to medical treatment or needling without adjunct antimetabolites. Among the 25 patients who developed an EB, 21 were followed for at least 6 months. A control group of 21 consecutive eyes, which underwent trabeculectomy during the same period and that did not develop EBs was retrospectively selected. Success was defined as IOP <21 mmHg with or without medications. Kaplan-Meier survival analysis was performed to compare the groups. RESULTS: Among the 21 eyes that developed EBs, 12 (57%) had undergone transconjunctival needling and nine (43%) had received medical treatment. Mean follow-ups were 30.0 +/- 14.0 months, 33.3 +/- 18.5 months, and 37.4 +/- 2.6 months for the needling, medical treatment, and control groups, respectively (P = 0.19). Kaplan-Meier survival curves demonstrated that the control group showed a significantly lower chance of failure than both the needling and the medical treatment groups (P < 0.0001). CONCLUSION: Encapsulated blebs may be associated with an increased risk for surgical failure.

Aged↗
PubMed2002

Retinal nerve fibre layer loss in patients with type 1 diabetes mellitus without retinopathy.

BACKGROUND/AIM: There is evidence suggesting the occurrence of neurovisual abnormalities in patients with diabetes without retinopathy. However, the determination of abnormalities in the neural and glial elements in vivo is difficult. The aim of this study was to investigate whether a retinal nerve fibre layer (RNFL) defect (as determined by scanning laser polarimetry, SLP) is present in patients without clinical manifestations of diabetic retinopathy. METHODS: 12 patients with type 1 diabetes mellitus (DM) without retinopathy or other diabetes induced microvascular complications, underwent a complete ophthalmological examination, including automated perimetry and RNFL measurements with a nerve fibre layer analyser GDx. The data were compared with a normal control group matched for age and sex. RESULTS: The superior segment retardation in patients with diabetes was lower than in the control group, based on the superior integral (0.19 (SD 0.06) v 0.23 (0.04) mm(2), p=0.03) and the superior average (71.0 (11.05) v 84.27 (10.56) microm, p=0.007) parameters. CONCLUSION: This finding may be indicative of significant nerve fibre loss in the superior segment of the retina in patients with type 1 diabetes mellitus but without retinopathy. The meaning of intraretinal differences in RNFL retardation, indicating asymmetric NFL loss, in patients with diabetes is yet not understood.

Adult↗
PubMed2001

Intraoperative mitomycin-C without conjunctival and Tenon's capsule touch in primary trabeculectomy.

OBJECTIVE: To verify whether intraoperative mitomycin C (MMC) without conjunctival and Tenon's touch is effective in inhibiting the development of thin, avascular blebs in eyes undergoing primary trabeculectomy. DESIGN: Noncomparative, interventional study. PARTICIPANTS: Fifteen eyes of 15 consecutive patients undergoing primary trabeculectomy. INTERVENTION: All eyes underwent trabeculectomy with intraoperative MMC (0.25 mg/ml for 3 minutes) without either conjunctival or Tenon's touch. Patients were examined 1 month, 3 months, 6 months, and 12 months after surgery. Intraocular pressure (IOP) and number of medications were evaluated at each examination. The appearance of the bleb was classified at the last examination into one of three groups: flat and vascularized; elevated but not avascular; or elevated, thin, and avascular. MAIN OUTCOME MEASURES: Intraocular pressure, number of antiglaucoma medications, and appearance of the bleb. RESULTS: Preoperative mean IOP was 30.57 +/- 10.92 mmHG: Statistically significant IOP reductions were observed 1 month, 3 months, 6 months, and 1 year after surgery (P < 0.01). Twelve months after surgery, the mean IOP was 14.92 +/- 6.53 mmHG: Five eyes (33.3%) showed an IOP less than 15 mmHg without antiglaucoma medication at the 12-month examination. The bleb was considered elevated, thin, and avascular in 12 of 15 eyes (80%) at the end of follow-up. CONCLUSIONS: Intraoperative MMC at 0.25 mg/ml for 3 minutes without either conjunctival or Tenon's touch was not effective in eliminating the development of thin, avascular blebs in eyes undergoing primary trabeculectomy.

Conjunctiva↗
PubMed2001

Exogenous vasopressin influences intraocular pressure via the V(1) receptors.

PURPOSE: To compare central, peripheral, and ocular effects of exogenously given vasopressin on intraocular pressure (IOP) and to identify the related receptor mechanisms of action in rabbits. METHODS: Young adult New Zealand albino rabbits were entrained under a daily 12-hour light and 12-hour dark cycle. In the early light period, bolus injections of vasopressin or desmopressin (a specific V(2) receptor agonist) were given either to the central nervous system (CNS) through an implanted cannula to the 3(rd) ventricle or to the systemic circulation via the ear vein in conscious rabbits. Changes in IOP and pupil size were monitored for up to 6 hours and dose-response curves were generated. Effects of centrally and peripherally given vasopressin on IOP were further examined following pretreatments with a selective V(1) receptor antagonist administered into the 3(rd) ventricle and into the ear vein, respectively. In order to clarify whether or not exogenously given vasopressin can alter IOP by mechanisms inside the eye, vasopressin was injected into the anterior chamber or the vitreous chamber unilaterally in conscious rabbits. Changes in IOP and pupil size were monitored. After an anterior chamber or intravitreal injection of the V(1) receptor antagonist, changes in IOP and pupil size due to an intravenous injection of vasopressin were determined to study the involvement of the related receptor mechanism. RESULTS: A dose-dependent elevation of IOP appeared after injections of vasopressin into the 3(rd) ventricle. There was no pupillary change. This IOP elevation was blocked by the pretreatment with the V(1) receptor antagonist. Following intravenous injections of vasopressin, significant reductions of IOP and pupil size occurred. These reductions were blocked by the pretreatment with the V(1) receptor antagonist. Intracerebroventricular or intravenous injection of desmopressin had no effect on IOP or pupil size. Injection of vasopressin into the anterior chamber or the vitreous chamber caused significant reductions of IOP and pupil size. Pretreatment with the V(1) receptor antagonist into the anterior chamber or the vitreous chamber prevented the reductions of IOP and pupil size following an intravenous injection of vasopressin. CONCLUSIONS: Intracerebroventricular and intravenous injections of vasopressin cause opposite effects on IOP. The central effect of vasopressin on IOP and the peripheral effects of vasopressin on IOP and pupil size are due to stimulations of the V(1) receptors. Reductions of IOP and pupil size following intravenous injections of vasopressin are at least partially due to stimulations of the V(1) receptors inside the eye.

Animals↗
PubMed2001

Discrimination between normal and glaucomatous eyes with visual field and scanning laser polarimetry measurements.

AIM: To evaluate the ability of structural parameters (as determined by retinal nerve fibre layer (RNFL) measurements obtained with the scanning laser polarimeter (SLP-NFA/GDx)) and functional parameters (as determined by automated perimetry) to discriminate between normal and glaucomatous eyes. METHODS: In a case-control study, a total of 91 normal subjects and 94 patients with glaucoma underwent automated perimetry and RNFL measurements obtained with the SLP. Three independent scans of each eye were obtained and a mean image was created and used for further analysis. Only one eye per individual was randomly included in the study. The sensitivity (Se) and specificity (Sp) of 12 RNFL parameters were calculated according to the SLP internal normative database. The Se and Sp of the visual field (VF) global indices and the glaucoma hemifield test (GHT) were also calculated according to the instrument's normative database. Receiver operator characteristic (ROC) curves were built for each SLP parameter and VF index. Fisher's linear discriminant formulas (LDFs) were developed for VF indices (VF LDF), SLP measurements (SLP LDF), and both examinations (combined LDF). RESULTS: According to the SLP internal database, the parameters with better Se and Sp were: superior/nasal ratio (Se = 58.5%; Sp = 86.8%), and GDx the number (Se = 43.3%; Sp = 96.7%). The construction of an ROC curve for the number resulted in Se = 84% and Sp = 79%. The creation of LDFs improved both the sensitivities and specificities when compared with isolated parameters SLP LDF (Se = 90.4%; Sp = 82.4%), VF LDF (Se = 89.4%; Sp = 89.0%), and combined LDF (Se = 93.0%; Sp = 90.1%). The sensitivity to diagnose early and moderate glaucomatous damage observed with the GHT was lower than that obtained with the number (p < 0.01). CONCLUSIONS: Creation of LDFs enhanced the Se and Sp for both VF and SLP. Integration of SLP and VF in a combined LDF reached the highest Se/Sp relation, suggesting that these examinations may be additive concerning the diagnosis of glaucoma. The SLP parameter the number may be more sensitive than the GHT in diagnosing early and moderate glaucomatous damage.

Adult↗
PubMed1999

The effects of carotid endarterectomy on the retrobulbar circulation of patients with severe occlusive carotid artery disease. An investigation by color Doppler imaging.

OBJECTIVE: To analyze the effects of carotid endarterectomy on the retrobulbar circulation of patients with severe occlusive carotid artery disease (OCAD) by means of color Doppler imaging (CDI). DESIGN: Prospective. PARTICIPANTS: A total of 17 consecutive patients with severe OCAD and neurologic symptoms (with a history of transitory ischemic attack or cerebral vascular accident) participated. INTERVENTION: All 17 patients underwent carotid endarterectomy. The CDI of both orbits was performed by one masked investigator before surgery and at 1 week and 1 month after surgery. MAIN OUTCOME MEASURES: Peak systolic velocity, end diastolic velocity, and resistive index of the ophthalmic, central retinal, and temporal short posterior ciliary arteries were measured. The authors compared the hemodynamic parameters at all intervals. RESULTS: Peak systolic and end diastolic velocities in the ophthalmic, central retinal, and temporal short posterior ciliary arteries increased significantly 1 week and 1 month after carotid endarterectomy (P < 0.05). After surgery, the resistive indices in the central retinal and temporal short posterior ciliary arteries decreased significantly at both intervals (P < 0.05). The six patients who had reversed ophthalmic artery flow before surgery showed forward ophthalmic artery flow after carotid endarterectomy. The contralateral orbits showed no significant hemodynamic change after endarterectomy (P < 0.05). CONCLUSIONS: Hemodynamic changes in patients with severe OCAD undergoing carotid endarterectomy suggest improvement in the ipsilateral retrobulbar blood flow.

Aged↗
PubMed1999

Latanoprost in glaucoma associated with Sturge-Weber syndrome: benefits and side-effects.

PURPOSE: This study was conducted to evaluate the ocular hypotensive efficacy, safety, and side effects of latanoprost 0.005% administered as adjunctive therapy in patients with Sturge-Weber syndrome (SWS) and glaucoma. METHODS: Commercially available latanoprost 0.005% was added as a single drop once daily to other antiglaucoma medications. Intraocular pressure (IOP) was measured at 1, 3, and 6 months of treatment. A successful response was defined as a reduction of at least 20% in IOP at the final follow-up evaluation without additional medical or surgical therapy and no adverse events related to latanoprost. RESULTS: 18 eyes of 18 patients with SWS and glaucoma were enrolled from 9 clinical centers. Mean baseline IOP was 28.4 +/- 7.1 mmHg (range, 17-42 mmHg). Using Kaplan-Meier analysis, a successful response to latanoprost was observed in 3 of 18 (16.7%) patients at the 6-month interval. Seven (38.9%) patients required surgery; three (16.7%) patients required additional medical therapy, seven (38.9%) patients had no change in therapy. One (5.6%) patient discontinued latanoprost treatment because of intolerable conjunctival hyperemia. Two successfully treated patients had significantly greater episcleral vessel engorgement after initiation of latanoprost therapy. CONCLUSION: Patients with SWS and glaucoma respond poorly to adjunctive latanoprost therapy and often require additional medical or surgical intervention. Increased episcleral vascular engorgement might result in greater operative risks should filtration surgery become necessary in these patients.

Adolescent↗
PubMed1998

Collateral blood supply through the ophthalmic artery: a steal phenomenon analyzed by color Doppler imaging.

OBJECTIVE: This study aimed to evaluate the retrobulbar circulatory effects of reversed ophthalmic artery flow (ROAF) on the ophthalmic artery branches by means of color Doppler imaging. DESIGN: The design was a case-controlled study. PARTICIPANTS: Among 56 consecutive patients with severe (>70% stenosis) occlusive carotid artery disease, 15 patients (26.8%) with ROAF were identified. The control group consisted of 15 patients with similar degrees of carotid artery stenosis and forward ophthalmic artery flow. INTERVENTION: Arteriography and measurement of the retrobulbar hemodynamic parameters with color Doppler imaging were performed. MAIN OUTCOME MEASURES: Blood flow velocities and resistive index in the ophthalmic, central retinal, and temporal short posterior ciliary arteries were measured. RESULTS: Arteriography confirmed the diagnosis of ROAF in all 15 patients. There was no patient with ROAF diagnosed by arteriography and not diagnosed by color Doppler imaging. The frequency of bilateral severe occlusive carotid artery disease was significantly higher in the ROAF group (40%) compared to the control group (6.6%) (P = 0.04). Patients with ROAF showed significantly reduced vascular resistance in the ophthalmic artery (P = 0.03), higher vascular resistance, and lower blood flow velocities in the central retinal and temporal short posterior ciliary arteries (P < 0.05). CONCLUSION: This study suggests that patients with ROAF show a steal phenomenon, characterized by a shunt to the low-resistance intracranial circuit and reduction of retrobulbar blood flow.

Aged↗
PubMed1998

[Evaluation of an educational program for patients with glaucoma].

PURPOSE: To analyze the results of an educational program applied to glaucoma patients; to serve as a guideline for a definitive educational program to be developed at the Glaucoma Service of the University of Campinas. METHODS: Fifty glaucoma patients were given information about the disease and its treatment by an experienced nurse and answered the same questionnaire before and 2.7 months after the initial explanation. The technique of eyedrop instillation was compared before and after the educational program. RESULTS: There was no significant improvement concerning the knowledge of the identification of the ocular disease, the side effects, the meaning of glaucoma, the importance of treatment, the purpose of medications and the normal value of intraocular pressure. There was a significant improvement in all steps of eyedrop instillation (p < 0.01) and in knowledge regarding the importance of heredity (p < 0.001) and the purpose of perimetry (p=0.033). CONCLUSION: Although a significant improvement was observed in the technique of eyedrop instillation, the authors conclude that this plan was not complete enough for its contents fully to be understood. These findings may be secondary to the vertical teaching-learning process, which is inappropriate for the patient, and to the difficulty in comprehending the information, which is associated with low cultural and instruction levels, and to psychosocial factors related to their disease.

Adolescent↗
PubMed1997

Diagnosing and monitoring carotid cavernous fistulas with color Doppler imaging.

Color Doppler imaging allows simultaneous bidimensional imaging and Doppler evaluation of blood flow in orbital vessels. We report 4 cases in which color Doppler imaging was used to diagnose and monitor carotid cavernous fistulas. In all cases, color Doppler imaging demonstrated dilated, arterialized superior ophthalmic veins; these findings were confirmed by angiography. Two patients underwent embolization with complete regression of the clinical findings. After embolization, color Doppler imaging revealed normal, laminar flow in the superior ophthalmic vein. This noninvasive technique represents a safe and fast method that is useful in the diagnosis and post-treatment follow-up of carotid cavernous fistulas.

Adult↗
PubMed1997

Clinical findings and hemodynamic changes associated with severe occlusive carotid artery disease.

OBJECTIVE: The purpose of the study was to evaluate the ophthalmologic findings and to analyze the retrobulbar hemodynamics of patients with severe (greater than 70% stenosis) occlusive carotid artery disease (OCAD) by means of color Doppler imaging (CDI). DESIGN: A case-controlled study. PARTICIPANTS: Fifty-six consecutive patients with severe OCAD and an age- and sex-matched control group consisting of 56 healthy patients without OCAD were studied. INTERVENTION: All 112 patients underwent a complete ophthalmologic examination. Color Doppler imaging of both orbits was performed by one masked investigator. MAIN OUTCOME MEASURES: Peak systolic velocity, end diastolic velocity, and the resistive index of the ophthalmic, central retinal, and temporal short posterior ciliary arteries were measured. The authors compared the hemodynamic parameters measured in patients with severe OCAD with those obtained in the control group. The hemodynamic parameters of patients with asymmetric OCAD (stenosis > 70% in one internal carotid artery and stenosis < 50% in the contralateral artery) were also compared. In an attempt to determine risk factors associated with the ocular ischemic syndrome (OIS), the authors compared patients with severe OCAD and OIS with patients with severe OCAD without OIS. RESULTS: Peak systolic and end diastolic velocities in the ophthalmic, central retinal, and temporal short posterior ciliary arteries were significantly lower in patients with severe OCAD (P < 0.01). The mean resistive indices in the central retinal and temporal short posterior ciliary arteries were higher in the group with severe OCAD (P < 0.01). Similar results were obtained in the analysis of 25 patients with asymmetric carotid stenosis. Younger age (P = 0.012), severe bilateral OCAD (P = 0.01), high-grade carotid stenosis (P = 0.013), and reversed ophthalmic artery flow (P = 0.038) were significant risk factors for OIS. CONCLUSIONS: Patients with severe OCAD show hemodynamic changes that suggest reduced retrobulbar blood flow. Patients with severe bilateral OCAD, high-grade carotid stenosis, and reversed ophthalmic artery flow may have a greater risk of developing OIS.

Aged↗
PubMed1997

Needling versus medical treatment in encapsulated blebs. A randomized, prospective study.

OBJECTIVE: The purpose of the study is to compare the efficacy and safety of transconjunctival needling and medical treatment in eyes with encapsulated blebs. DESIGN: A randomized, prospective study. PARTICIPANTS: Two hundred eighty-two eyes that underwent a guarded filtration procedure between January 1994 and January 1996 at the Glaucoma Service of University of Campinas. INTERVENTION: Encapsulated blebs developed in 25 (8.9%) of 282 eyes and were randomized to either needling (n = 14) or medical treatment with aqueous humor suppressants (n = 11). If one treatment failed to maintain intraocular pressures (IOPs) below 20 mmHg, the other treatment was initiated. If both methods failed, surgical revision or further glaucoma surgery was performed. Complete success was defined as IOP less than 20 mmHg after one treatment method. Qualified success was defined when IOPs less than 20 mmHg were obtained with both treatment methods, whereas failure was defined when IOP greater than 20 mmHg or when further surgery was indicated. MAIN OUTCOME MEASURES: Intraocular pressure, vision, and number of antiglaucoma medications. RESULTS: After a mean follow-up of 9.6 months, medical treatment alone was successful in ten patients (90.9%), whereas needling alone was successful in one patient (7.1%) (P = 0.00003). In the needling group, 92.9% of the eyes required aqueous humor suppressants, and 57.1% were considered qualified successes at the last follow-up (mean = 10.1 months). At the last follow-up examination, there was no statistically significant difference between the mean number of medications in both groups (P = 0.797). Further glaucoma surgery was performed in five patients (35.7%) undergoing needling and one patient (9.1%) receiving medical treatment (P = 0.162). CONCLUSIONS: Medical treatment with digital pressure should be used as the initial treatment in eyes with encapsulated blebs. Needling procedures or surgical revision, methods that are more invasive and potentially associated with severe complications, should be limited to the small percentage of eyes that do not respond to medical treatment.

Adrenergic beta-Antagonists↗
PubMed1997

Ophthalmic artery aneurysms: an investigation by duplex scan.

With the objective of analyzing the postaneurysmal peak systolic velocity (PSV) in ophthalmic arteries, duplex scanning was analyzed in 28 carotid-ophthalmic artery segments after exclusion of ipsilateral carotid stenosis. For comparison, the angiographic study of the extracranial and intracranial carotid system was utilized as the "gold standard." A subgroup of 7 subjects with 8 ophthalmic arteries with aneurysms identified where the artery leaves the internal carotid artery presented with PSVs significantly reduced (mean PSVs 17.95 +/- 7.99 cm/s) compared to the mean PSVs in the healthy group (27.95 +/- 5.54 cm/s) (p = 0.006). A PSV of less than 19 cm/s offered a sensitivity of 80% and a specificity of 100% in diagnosing ophthalmic artery aneurysms. We conclude that duplex scan is diagnostically useful in the identification of patients with ophthalmic artery aneurysms when severe ipsilateral carotid stenosis is excluded.

Adult↗
PubMed1996

Low-dose mitomycin C trabeculectomy in patients with advanced glaucoma.

PURPOSE: The purpose of this study was to analyze the efficacy and safety of low-dose (0.2 mg/ml) intraoperative mitomycin C in primary trabeculectomy. METHODS: Twenty-eight eyes of 28 patients with advanced primary open-angle glaucoma undergoing primary trabeculectomy were randomized to either mitomycin C (0.2 mg/ml) or saline solution intraoperatively for 3 min. Intraocular pressure was measured at 1 day; 1 week; 1, 3, and 6 months postoperatively; and at the final visit. RESULTS: Mean follow-up was 17.0 +/- 5.6 months for the mitomycin C group and 15.7 +/- 5.1 months for the control group. Mean intraocular pressures were significantly lower in the treated group on the first postoperative day (p = 0.021), at the 6-month interval (p = 0.001), and at the final visit (p = 0.001). At the last follow-up examination, intraocular pressure was < or = 15 mm Hg in 12 (85.7%) of the mitomycin C-treated eyes and in four (28.6%) of the control eyes (p = 0.002). Life table analysis showed a significantly higher probability of intraocular pressure control in the mitomycin C group than in the control group (p = 0.0065). Choroidal effusion was observed in five (35.7%) treated eyes and two (14.3%) control eyes, whereas shallow anterior chamber were present in five (35.7%) treated eyes and one control eye (7.1%). CONCLUSION: Despite inducing a higher short-term complication rate, low-dose mitomycin C may be an alternative in the treatment of eyes with advanced glaucomatous damage requiring low final intraocular pressures.

Aged↗
PubMed1994

Color Doppler imaging: methodology and preliminary results in glaucoma.

Color Doppler imaging (CDI) has recently been applied to investigation of the normal vascular anatomy of the eye and orbit as well as a variety of conditions in which vascular abnormalities are important. Combining B-scan ultrasonography and Doppler waveform analysis, CDI enables noninvasive serial examination of blood velocity and vascular resistance from the ophthalmic, short posterior, ciliary and central retinal arteries. This technology is being used to study the ophthalmic circulation of patients with primary open-angle or normotension glaucoma.

Blood Flow Velocity↗