Validation of direct method to quantify dexamethasone in human aqueous humor by LC-MS/MS.

AIM: Dexamethasone (Dex) has been used for the treatment of ocular diseases, presenting concentrations up to 150 ng/ml in the biological matrix. Drug sampling has been performed from aqueous humor (AH), which the volume varies from 50 to 200 µl, becoming a challenge for analytical analyses. RESULTS: We developed and validated a direct and sensitive method by LC-MS/MS for Dex measurement in human AH, using water as surrogate matrix to reduce the sample volume applied in some validation assays. With accuracies of 99.6% and precision within 15% in the range of 0.1-150 ng/ml, Dex had an 87-day stability. CONCLUSION: Our method is robust and sensitive enough to be applied in bioequivalence studies with human AH using only 20 µl of biological sample.

Indications and visual outcomes of intrastromal corneal ring segment implantation in a large patient series.

OBJECTIVES:: To describe the indications for and visual outcomes of intrastromal corneal ring segment implantation. METHODS:: A large retrospective case-series chart-review study was conducted using Sorocaba Ophthalmological Hospital medical records. This study included 1222 eyes (1196 patients) that were surgically treated between November 2009 and December 2012. The following preoperative data were collected: age, gender, type of medical care and funding source, surgical technique, best-corrected visual acuity, manifest sphere and cylinder refractive error, maximum and minimum central keratometry, and pachymetry measurements of the cornea at the thinnest point and at the ring channel. The postoperative best-corrected visual acuity and patient satisfaction were also determined. The cases were classified into six groups: four keratoconus groups (severe, advanced, moderate and mild), a pellucid marginal degeneration group and a post-graft irregular astigmatism group. This study was approved by the Brazilian Registry of Clinical Trials (UTN number 1111-1182-6181, TRIAL RBR-6S72RF). RESULTS:: The age (mean±standard deviation) of the patients was 31.0±10.0 years. The most prevalent pathology was keratoconus (1147 eyes, 93.8%). A correlation was found between ectasia severity and medical assistance (p<0.001), and the most serious cases was treated by the Brazilian public health system. No complications were found in a total of 1155 surgeries, and after surgery, 959 patients were satisfied. Among the 164 dissatisfied patients, the majority failed to show improved best-corrected visual acuity. CONCLUSION:: Patients in the public health system underwent surgical intervention for keratoconus later than those with private sources of funding. In the vast majority of operated cases, the patients reported improvements in vision.

Glaucoma Diagnostic Accuracy of Machine Learning Classifiers Using Retinal Nerve Fiber Layer and Optic Nerve Data from SD-OCT.

Purpose. To investigate the diagnostic accuracy of machine learning classifiers (MLCs) using retinal nerve fiber layer (RNFL) and optic nerve (ON) parameters obtained with spectral domain optical coherence tomography (SD-OCT). Methods. Fifty-seven patients with early to moderate primary open angle glaucoma and 46 healthy patients were recruited. All 103 patients underwent a complete ophthalmological examination, achromatic standard automated perimetry, and imaging with SD-OCT. Receiver operating characteristic (ROC) curves were built for RNFL and ON parameters. Ten MLCs were tested. Areas under ROC curves (aROCs) obtained for each SD-OCT parameter and MLC were compared. Results. The mean age was 56.5 ± 8.9 years for healthy individuals and 59.9 ± 9.0 years for glaucoma patients (P = 0.054). Mean deviation values were -1.4 dB for healthy individuals and -4.0 dB for glaucoma patients (P < 0.001). SD-OCT parameters with the greatest aROCs were cup/disc area ratio (0.846) and average cup/disc (0.843). aROCs obtained with classifiers varied from 0.687 (CTREE) to 0.877 (RAN). The aROC obtained with RAN (0.877) was not significantly different from the aROC obtained with the best single SD-OCT parameter (0.846) (P = 0.542). Conclusion. MLCs showed good accuracy but did not improve the sensitivity and specificity of SD-OCT for the diagnosis of glaucoma.

Indications and visual outcomes of intrastromal corneal ring segment implantation in a large patient series

OBJECTIVES: To describe the indications for and visual outcomes of intrastromal corneal ring segment implantation. METHODS: A large retrospective case-series chart-review study was conducted using Sorocaba Ophthalmological Hospital medical records. This study included 1222 eyes (1196 patients) that were surgically treated between November 2009 and December 2012. The following preoperative data were collected: age, gender, type of medical care and funding source, surgical technique, best-corrected visual acuity, manifest sphere and cylinder refractive error, maximum and minimum central keratometry, and pachymetry measurements of the cornea at the thinnest point and at the ring channel. The postoperative best-corrected visual acuity and patient satisfaction were also determined. The cases were classified into six groups: four keratoconus groups (severe, advanced, moderate and mild), a pellucid marginal degeneration group and a post-graft irregular astigmatism group. This study was approved by the Brazilian Registry of Clinical Trials (UTN number 1111-1182-6181, TRIAL RBR-6S72RF). RESULTS: The age (mean±standard deviation) of the patients was 31.0±10.0 years. The most prevalent pathology was keratoconus (1147 eyes, 93.8%). A correlation was found between ectasia severity and medical assistance (p<0.001), and the most serious cases was treated by the Brazilian public health system. No complications were found in a total of 1155 surgeries, and after surgery, 959 patients were satisfied. Among the 164 dissatisfied patients, the majority failed to show improved best-corrected visual acuity. CONCLUSION: Patients in the public health system underwent surgical intervention for keratoconus later than those with private sources of funding. In the vast majority of operated cases, the patients reported improvements in vision.