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Miguel J Maldonado

Publications and source records attributed to Miguel J Maldonado.

16 recordsLinked to original sources
PubMed2006

Bilateral ischemic optic neuropathy after transurethral prostatic resection: a case report.

BACKGROUND: Nonarteritic ischemic optic neuropathy affects the anterior portion of the optic nerve and is characterized by sudden, painless visual loss. The affected eye has a relative afferent pupillary defect. The typical funduscopic appearance includes optic disc edema, with associated nerve fiber layer hemorrhage. Risk factors include advanced age, systemic hypertension, nocturnal hypotension, diabetes mellitus, and a small cup-to-disc ratio. Bilateral presentation is rare. Postoperative optic neuropathy has been associated with nonocular surgery; risk factors include a combination of prolonged surgical times, acute systemic hypotension, anemia due to blood loss, or prone positioning. We report for the first time a patient with bilateral, simultaneous anterior ischemic optic neuropathy after elective transurethral prostatic resection. CASE PRESENTATION: A 66-year old man underwent surgery for benign prostatic hyperplasia. The preoperative blood pressure was 140/85 mmHg, hemoglobin 15.9 g/dL, and hematocrit 48.6%. Two hours postoperatively, the blood pressure, hemoglobin, and hematocrit dropped dramatically. One day later, transient horizontal diplopia developed. Funduscopy showed a congenitally small cup-to-disc ratio without papillary edema. Other ocular findings were unremarkable. By 4 days postoperatively, sudden and painless amaurosis bilaterally developed when the patient awoke with nausea and vomiting. Visual acuity was no light perception bilaterally. The optic discs were swollen with small hemorrhages. Scans of the head and orbits and electrolyte levels were normal. There were no responses on visual evoked potentials bilaterally. The blood pressure was 90/50 mm Hg, the hemoglobin 7.0 g/dL, and the hematocrit 22.9%, necessitating infusion of three units of packed red blood cells. The blood pressure, hematocrit, and hemoglobin increased to normal levels. Three months later the visual acuity remained no light perception. The pupils were unreactive and there was marked optic disc atrophy bilaterally. CONCLUSION: Bilateral and simultaneous acute ischemic optic neuropathy may be a rare but devastating surgical complication. The combination of anemia and hypotension may increase the risk of anterior ischemic optic neuropathy postoperatively after transurethral prostatic resection.

Aged↗
PubMed2006

Repeatability and reproducibility of posterior corneal curvature measurements by combined scanning-slit and placido-disc topography after LASIK.

OBJECTIVE: To assess the repeatability and reproducibility of posterior corneal curvature (PCC) measurements made by combined scanning-slit/Placido-disc topography (Orbscan II) after LASIK. DESIGN: Experimental instrument validation study. PARTICIPANTS: We recruited 22 consecutive postmyopic LASIK patients for the repeatability study and another 50 consecutive postmyopic LASIK patients for the reproducibility study. METHODS: To analyze intrasession repeatability, 1 examiner measured 22 postmyopic LASIK eyes 10 times successively in the shortest time possible. To study intersession reproducibility, the same operator obtained measurements from another 50 eyes with stable refraction in 2 consecutive visits at the same time of the day between 6 and 9 months after myopic LASIK. We explored any association between residual stromal bed thickness and measurement variability. MAIN OUTCOME MEASURES: Orbscan II scanning-slit PCC data, precision, within-subject coefficient of variation (CV(w)), limits of agreement (LoA), and intraclass correlation coefficient (ICC). RESULTS: For intrasession repeatability, precision was 0.067 mm (best-fit sphere [BFS]), 0.110 diopters (D; power within 5 mm), 0.158 D (power within 3 mm), and 0.46 (eccentricity). Repeatability was high for PCC BFS and power measurements within 3-mm and 5-mm zones (CV(w) ranged from 0.5%-1.2%) but poor for eccentricity data (CV(w), 31.6%). Correspondingly, ICCs ranged from 0.89 to 0.98 for PCC BFS and power, and the ICC was 0.20 for PCC eccentricity values. For intersession reproducibility, on average, no difference in PCC measurements could be found, indicating that when there is variability, it is due to random factors. The width of the 95% LoA between sessions was clinically acceptable for BFS (0.25 mm) and power (0.4 D [within 5 mm] and 0.6 D [within 3 mm]). Similarly, ICCs indicated good intersession reliability for BFS and power (0.98, 0.96, and 0.85 for BFS, power within 5 mm, and power within 3 mm, respectively) but poor reliability for eccentricity (0.59). Repeatability and reproducibility were unrelated to stromal bed thickness. CONCLUSIONS: Orbscan II provides reliable post-LASIK PCC data for symmetrical parameters (BFS and power), independent of the residual stromal bed thickness, but is unreliable for measurements that are radially asymmetrical (eccentricity). Orbscan II is useful for monitoring the PCC after LASIK once the early postoperative period is over.

Adult↗
PubMed2006

Cataractous changes due to posterior chamber flattening with a posterior chamber phakic intraocular lens secondary to the administration of pilocarpine.

OBJECTIVE: To present the first reported case of cataract formation as a consequence of instillation of pilocarpine in an eye with a posterior chamber phakic intraocular lens (IOL). DESIGN: Interventional case report. INTERVENTION: A 46-year-old man received a hyperopic implantable collamer lens (ICL) bilaterally. MAIN OUTCOME MEASURES: Determination of best-corrected visual acuity (BCVA); contrast sensitivity testing with and without glare; and intraocular pressure (IOP), specular endothelial cell, and slit-lamp examinations were performed serially. In addition, the distance between the ICL and crystalline lens was measured with optical coherence tomography. RESULTS: Both eyes underwent uneventful ICL implantation for the correction of a manifest spherical equivalent of +7 diopters (D) in the right eye and +7.1 D in the left eye. The left eye was followed for 2 years without developing complications. The right eye, however, showed on the first postoperative day a fleckenlike opacification on the anterior pole of the crystalline lens after instillation on the operative day of 2% pilocarpine in an attempt to accelerate recovery from unwanted pupil dilation causing patient complaints of glare disability after surgery. Optical coherence tomography demonstrated complete contact of the ICL with the natural lens 24 hours postoperatively. Serial IOP measurements were always within the normal limits. The instillation of 1% cyclopentolate resulted in an increase in the ICL vault that measured 132 mum 24 hours later. Three days after the completion of a 3-day course of topical 1% cyclopentolate, the opacification was less dense and demarcated, and a 124-mum vault was measured. Three months postoperatively, the cataract was associated with a 3-line loss of BCVA and considerable degradation of the contrast sensitivity, especially at higher spatial frequencies and with a glare source, and corneal endothelial cell changes were within normal limits. One year after ICL implantation, the right eye had to undergo phacoemulsification and IOL implantation, which were uneventful. CONCLUSIONS: Posterior chamber flattening with resulting crystalline lens opacification can occur immediately after the instillation of pilocarpine in an eye with a hyperopic ICL. Therefore, caution should be taken with the administration of cholinergic agonists such as pilocarpine in patients with phakic IOLs, at least if they are hyperopic ICLs.

Cataract↗
PubMed2006

Posterior corneal curvature changes after undersurface ablation of the flap and in-the-bed LASIK retreatment.

OBJECTIVE: To analyze LASIK retreatment-induced changes in the posterior corneal curvature (PCC) with undersurface ablation of the flap (UAF) and in-the-bed techniques. DESIGN: Nonrandomized, comparative, interventional study. PARTICIPANTS: Forty-six eyes with a residual spherical equivalent refraction between -0.37 and -2.75 diopters (D) and astigmatism between 0.0 and -1.25 D were included prospectively. In 23 eyes, the calculated postenhancement flap thickness exceeded 150 microm using micropachymetric optical coherence tomography, whereas with further ablation of the bed, the residual bed thickness (RBT) would have been <250 microm, or <55% of the pre-LASIK central pachymetry. In another 23 eyes, RBT allowed the planned ablation for a calculated post-retreatment RBT exceeding 250 microm, >55% of the pre-LASIK central pachymetry. INTERVENTION: Eyes with insufficient RBT for further ablation underwent UAF retreatment, whereas those with adequate RBT received conventional in-the-bed LASIK retreatment. Examinations were performed before retreatment and 3 and 6 months postoperatively. No eye was lost to follow-up. MAIN OUTCOME MEASURES: Micropachymetry, Orbscan II scanning-slit PCC data, and visual acuity (VA). RESULTS: The groups did not differ in age, intraocular pressure, or retreatment ablation depth, but the UAF eyes had a lower mean pre-retreatment RBT (270.7+/-25.4 microm) than conventional enhancement eyes (353.0+/-41.5 microm) (P = 0.001). Eyes undergoing UAF had no significant change in PCC, whereas eyes undergoing conventional retreatment had an increase in the posterior corneal power within the central 3-mm zone (P = 0.008) 3 months after retreatment. No significant changes occurred thereafter. The amount of change in posterior corneal power within the 3-mm central zone from before to after retreatment differed significantly between the groups (mean difference, 0.135 D; 95% confidence interval, 0.022-0.248 D; P = 0.02). No keratectasia developed clinically, and no retreated eye lost or gained > or =2 lines of best-corrected VA. Six months after retreatment, the efficacy and safety indices for the UAF procedure were 0.96 and 1.01, respectively, and 1 and 1.06 for conventional LASIK enhancement. CONCLUSION: Undersurface ablation of the flap retreatment appears to have less potential for changing the posterior corneal surface than conventional LASIK enhancement and can help reduce the likelihood of retreatment-induced keratectasia.

Adult↗
PubMed2005

Laser-assisted in situ keratomileusis posterior ablation platform.

A laser-assisted in situ keratomileusis posterior ablation platform was developed to improve the ease and quality of the undersurface ablation of the flap technique. This ergonomic instrument combines a fixation ring with a platform that provides a physiologically spherical and smooth, low-reflective surface to extend the turned flap during the undersurface ablation of the flap retreatment. It was used successfully in 17 enhancement procedures when there was insufficient posterior stroma for additional treatment but adequate flap stroma. The result was improved globe stabilization and stromal smoothness during ablation. An efficacy index of 1 was achieved day 1 postoperatively in a greater percentage of eyes (88.2%) than without its use (29.4%; P = .001). The L-PAP appears to facilitate UAF procedures and prompt visual recovery.

Adult↗
PubMed2005

Using optical coherence tomography to monitor photodynamic therapy in age related macular degeneration.

PURPOSE: To evaluate the role of optical coherence tomography (OCT) in determining choroidal neovascularization (CNV) activity before and after photodynamic therapy (PDT) in patients with age-related macular degeneration (ARMD). DESIGN: Prospective observational case series. METHODS SETTING: Institutional study. patient population: Fifty-three patients (62 eyes) with ARMD. OBSERVATION PROCEDURE: Prospective observational case study. MAIN OUTCOME MEASURES: Presence or absence of leakage on fluorescein angiography, presence of intraretinal or sub-retinal fluid on OCT, and macular and choroidal neovascular complex thickness on OCT. RESULTS: The macular thickness decreased significantly after PDT (P = .001). However, no significant changes in CNV thickness were measured after PDT (P = .567). Once the diagnosis of ARMD was established before treatment, OCT had a sensitivity of 96.77% for detecting CNV activity. After treatment, OCT had a good sensitivity (95.65%) and a moderate specificity (59.01%) in determining CNV activity, which resulted in a diagnostic efficiency (proportion of correct results) of 82.95%. CONCLUSIONS: OCT appears to be useful for indicating CNV activity. Therefore, it may serve as a complementary technique for deciding the need for PDT and re-treatment in patients with ARMD.

Aged↗
PubMed2005

Flap tearing during lift-flap laser in situ keratomileusis retreatment.

A flap tear occurred during laser in situ keratomileusis (LASIK) retreatment using a flap-lifting technique in 1 eye of 2 patients 4 to 5 months after the primary procedure. In the first case, the tear occurred in a decentered, standard thickness flap (168 mum) in a location close to the corneal limbus and limbal vessels. In the second case, the tear occurred in a well-centered thin flap (116 mum) that involved a peripheral corneal pannus. The false track was identified early, and central extension of the tear was averted. After the flap was successfully dissected, retreatment was performed without further complications. This report suggests that flaps with margins near the limbus or a corneal pannus may be prone to an earlier and stronger healing process at the edge that may lead to a flap tear during LASIK retreatment. This may be of increasing importance because of the trend toward larger flap diameters.

Adult↗
PubMed2005

Objective quantification of posterior capsule opacification after cataract surgery, with optical coherence tomography.

PURPOSE: To evaluate posterior capsule opacification (PCO) in humans after cataract surgery with intraocular lens (IOL) implantation, by using optical coherence tomography (OCT-1). METHODS: Sixty-six eyes with PCO and 20 eyes with a normal posterior capsule were analyzed. A 3-mm-long horizontal scan of the posterior capsule was obtained. Measurements at three points and their average were recorded. Intraoperator and interoperator reliabilities were assessed. Investigated was peak intensity (PI) and posterior capsule thickening (PCT), with PCT indicating the distance between two reflectivity spikes, with an approximate axial resolution of 10 microm. Results were compared with visual acuity (VA) and PCO type. RESULTS: Intraoperator reliability was 0.59 and 0.97 for average PI and PCT, respectively. The interoperator concordance correlation coefficient was 0.70 and 0.82 for average PI and PCT, respectively. Median (interquartile range) intensities of the reflectivity spike were 16.88 (dB) (range, 12.88-20.41) and 11.9 (8.58-14.28), respectively, in the PCO and control eyes (P = 0.001). PCT was found in PCO eyes (median: 86.13 microm; range, 46.33-115.33), whereas no second spike appeared in control eyes (P = 0.001). The area under the receiver operating characteristic curve of the average PCT for differentiating pearl-type from fibrosis-type PCO was 0.87 (P = 0.001). For a cutoff point of 55.3 microm, the sensitivity was 97.5%, and the specificity was 69%. Worse VA correlated significantly only with larger PCT (r(o) = 0.66; P = 0.01). CONCLUSIONS: OCT-1 appears useful to quantitate PCO. In addition, this system seems to discriminate between different types of PCO. PCT may be a previously unrecognized factor in VA degradation.

Adolescent↗
PubMed2003

Intraoperative and postoperative complications of Cionni endocapsular ring implantation.

PURPOSE: To analyze the intraoperative and postoperative complications of Cionni ring implantation in eyes with a subluxated lens or zonular weakness. SETTING: Departamento de Oftalmología, Clínica Universitaria de Navarra, Universidad de Navarra, Pamplona, Spain. METHODS: This case series comprised 7 eyes of 5 patients with a subluxated lens or zonular weakness secondary to Marfan's syndrome (n = 2), traumatic cataract (n = 2), or megalocornea (n = 1) or of unknown etiology (n = 2). An AcrySof (Alcon) foldable intraocular lens (IOL) was implanted in all eyes. A 2-eyelet Cionni ring was implanted in 1 eye and a 1-eyelet Cionni ring, in 6 eyes. The Cionni ring was secured in position with a transscleral suture knotted to the ring's hook, avoiding peripheral perforation of the capsular bag. RESULTS: In 1 eye, corectopia was inadvertently produced by passing the suture needle through the iris root; lens subluxation temporarily increased during ring rotation and implantation. However, after the transscleral suture was tightened, capsular bag centration was excellent. In the eye with megalocornea, traction from the 2 hooks tore the edge of the anterior capsule rim. The most frequent postoperative complication was posterior capsule opacification, which occurred in 5 eyes, 2 of which required a neodymium:YAG posterior capsulotomy. After 1 year, the Cionni ring continued to provide excellent stability and capsular bag and IOL positioning in all cases. CONCLUSIONS: Results indicate that Cionni ring implantation is an acceptable procedure to correct limited lens subluxation, preserves the capsular bag, and has few significant complications.

Acrylic Resins↗
PubMed2002

Undersurface ablation of the flap for laser in situ keratomileusis retreatment.

OBJECTIVE: To develop a novel technique, undersurface ablation of the flap (UAF), for laser in situ keratomileusis (LASIK) retreatment in eyes with insufficient posterior stroma. DESIGN: Noncomparative, interventional case series. PARTICIPANTS: From 30 eyes examined, 25 eyes with a spherical equivalent residual refraction between -0.75 and -3.25 diopters (D) and astigmatism between 0.0 and -1.5 D were prospectively included in the study. In these eyes, calculated postenhancement flap thickness was >150 micro m using micropachymetric optical coherence tomography (OCT), whereas with further ablation of the bed, posterior stromal thickness would have been <250 micro m. Primary LASIK procedures had been performed with the Hansatome microkeratome. INTERVENTION: The flap was lifted and the eye deviated downward, so that the corneal visual axis mark aligned with the laser beam. Mirror pattern ablations with an optical zone of 5 mm were performed on the flap stroma using either the Summit Apex Plus excimer laser or the Technolas Keracor 217 spot-scanning excimer laser. New axis orientation for toric ablations was calculated with the formula: beta = 180 degrees - alpha. MAIN OUTCOME MEASURES: Refraction, visual acuity, OCT pachymetry, tangential videokeratography, and patient satisfaction. RESULTS: The average follow-up was 6.36 +/- 2.64 months (range, 3-12 months). Mean preenhancement spherical equivalent (-2.05 +/- 0.75 D) was reduced to -0.19 +/- 0.38 D at the last visit (P = 0.001). Mean cylinder decreased from -0.48 +/- 0.53 D before retreatment to -0.23 +/- 0.28 D at the last follow-up (P = 0.003). Best-corrected visual acuity worsened by 1 line in two eyes (8%), and no eye lost 2 or more lines. Satisfactory globe stabilization and stromal smoothness during ablation were more difficult to achieve than with conventional LASIK enhancements. The average central flap thickness before UAF, 187 +/- 13 micro m, decreased to 164 +/- 12 micro m after 1 month (P = 0.001). No keratectasia developed. Finally, 92% of cases were satisfied with surgery compared with 48% before UAF retreatment (P = 0.001). CONCLUSIONS: UAF retreatment for low residual refractive errors after LASIK in eyes with sufficient flap stroma seems to be effective and may prevent future keratectasia.

Adult↗
PubMed2002

Extensive corneal epithelial defect associated with internal hordeolum after uneventful laser in situ keratomileusis.

This report illustrates a retrospective case review in which extensive corneal epithelial ulceration occurred concomitantly with an internal hordeolum in the inferior forniceal conjunctiva 24 hours after an uneventful laser in situ keratomileusis. The internal hordeolum and epithelial defect were successfully managed using a bandage soft contact lens, a course of topical dexamethasone and tobramycin, and generous lubrication.

Administration, Topical↗
PubMed2002

Retinal thickness study with optical coherence tomography in patients with diabetes.

PURPOSE: To quantitatively assess retinal thickness by optical coherence tomography (OCT) in normal subjects and patients with diabetes. This study was intended to determine which retinal thickness value measured with OCT best discriminates between diabetic eyes, with and without macular edema. METHODS: OCT retinal thickness was measured by a manual technique in a total of 26 healthy volunteers (44 control eyes) and 85 patients with diabetes (148 eyes) with the clinical diagnosis of no diabetic retinopathy (45 eyes), nonproliferative diabetic retinopathy without clinically significant macular edema (CSME; 54 eyes), proliferative diabetic retinopathy without CSME (21 eyes), and 28 eyes with diabetic retinopathy with CSME. Independent predictors of the presence of CSME were quantified by using univariate and multivariate logistic regression analyses. Receiver operating characteristic (ROC) curves were generated to evaluate and compare the predictor variables. The correlation of retinal thickness measurements and visual acuity was calculated. RESULTS: There were statistically significant differences in foveal thickness between control eyes and all the other eye groups (P = 0.001). Diabetic eyes with CSME had a statistically significant greater thickness in each of the areas compared with the other groups. In a multivariate logistic regression model, foveal thickness was a strong and independent predictor of CSME (odds ratio [OR], 1.037; 95% confidence interval [CI] 1.02-1.05). The area under the ROC curve of this predictor variable was 0.94 (P = 0.001). For a cutoff point of 180 microm, the sensitivity was 93%, and specificity was 75%. Foveal thickness correlated with visual acuity in a log minimum angle of resolution (logMAR) scale (Spearman's rho = 0.9, P = 0.001). CONCLUSIONS: These results suggest that foveal thickening over 180 microm measured by OCT may be useful for the early detection of macular thickening and may be an indicator for a closer follow-up of the patient with diabetes.

Adult↗
PubMedDate not supplied

Subtarsal flap dislocation after superior hinge laser in situ keratomileusis in a patient with borderline mental illness.

PURPOSE: To report a case of complete subtarsal flap dislocation after uncomplicated superior hinge laser in situ keratomileusis (LASIK). METHODS: Flap dislodgement resulted from eye rubbing in a patient with a past medical history of mental illness and epilepsy. The dislocated cap, which was also folded in half, was refloated, profusely irrigated, and ironed to eliminate flap wrinkles. Particular care was taken to avoid flap misalignment. RESULTS: Despite the above mentioned intervention, a prominent epithelial mark corresponding to the line of previous folding persisted for 3 additional days. Eventually, a perfectly aligned lenticule without wrinkles and an otherwise normal postoperative course occurred. CONCLUSIONS: Although superior hinge LASIK may reduce the likelihood of flap displacement, mechanical forces can generate complete flap dislocation. When a flap has been folded in half, an epithelial mark corresponding to the line of folding may persist. Patients with psychiatric disorders may be at higher risk of postoperative flap-related complications.

Corneal Stroma↗