The present study was undertaken to determine whether exposure of the sclera to prostaglandin (PG)F(2alpha) or to the PGF(2alpha) analogue latanoprost acid alters mRNA for matrix metalloproteinases.
...Fifteen human eye bank eyes were studied. Circular pieces of sclera were either immediately preserved in a stabilization reagent or cultured in low-serum DMEM/F-12 medium. The cultures were treated for 24 hours with medium supplemented with PGF(2a), latanoprost acid, or vehicle. Total RNA was then isolated, and the expression of mRNA for matrix metalloproteinase (MMP)-1, -2, -3, -8, -9, -10, and -12 were determined by real-time PCR. All results were normalized according to the GAPDH mRNA in each sample. Altered mRNA expression after PG treatments also was evaluated with microarrays containing 19 MMP genes and 4 tissue inhibitor of matrix metalloproteinase (TIMP) genes.
Real-time PCR results showed that 24 hours of exposure to 100 nM PGF(2alpha) significantly increased mRNA for MMP-1 and -9 (P < 0.06 Wilcoxon test) and that exposure to 100 nM latanoprost acid significantly increased mRNA for MMP-9 (P < 0.06 Wilcoxon test). Array analysis demonstrated increases of MMP-3 and -10 mRNA after exposure to 100 nM latanoprost and further increases after exposure to 200 nM latanoprost. The array results also showed that latanoprost induced dose-dependent increases in the expression of TIMP-1, -2, and -3 mRNA in the scleral cultures.
PGF(2alpha) and latanoprost acid induce coordinated alterations of MMP gene transcription in scleral organ cultures. These results indicate that PGs can directly trigger MMP gene transcription changes within the sclera. These changes support a role for increased MMPs in the enhancement of uveoscleral outflow that occurs after topical treatment with latanoprost.
We report the results of repeated ambulatory continuous 24-hour intraocular pressure (IOP) monitoring with a contact lens sensor (CLS) in a glaucoma patient with ocular pain after ab interno ...trabeculotomy (Trabectome™) surgery. Our findings show that a combined prostaglandin-pilocarpine treatment reduced nighttime IOP peaks and relieved the patient's symptoms.
To classify healthy and glaucomatous eyes using relevance vector machine (RVM) and support vector machine (SVM) learning classifiers trained on retinal nerve fiber layer (RNFL) thickness measurements ...obtained by scanning laser polarimetry (SLP).
Seventy-two eyes of 72 healthy control subjects (average age = 64.3 +/- 8.8 years, visual field mean deviation = -0.71 +/- 1.2 dB) and 92 eyes of 92 patients with glaucoma (average age = 66.9 +/- 8.9 years, visual field mean deviation = -5.32 +/- 4.0 dB) were imaged with SLP with variable corneal compensation (GDx VCC; Laser Diagnostic Technologies, San Diego, CA). RVM and SVM learning classifiers were trained and tested on SLP-determined RNFL thickness measurements from 14 standard parameters and 64 sectors (approximately 5.6 degrees each) obtained in the circumpapillary area under the instrument-defined measurement ellipse (total 78 parameters). Ten-fold cross-validation was used to train and test RVM and SVM classifiers on unique subsets of the full 164-eye data set and areas under the receiver operating characteristic (AUROC) curve for the classification of eyes in the test set were generated. AUROC curve results from RVM and SVM were compared to those for 14 SLP software-generated global and regional RNFL thickness parameters. Also reported was the AUROC curve for the GDx VCC software-generated nerve fiber indicator (NFI).
The AUROC curves for RVM and SVM were 0.90 and 0.91, respectively, and increased to 0.93 and 0.94 when the training sets were optimized with sequential forward and backward selection (resulting in reduced dimensional data sets). AUROC curves for optimized RVM and SVM were significantly larger than those for all individual SLP parameters. The AUROC curve for the NFI was 0.87.
Results from RVM and SVM trained on SLP RNFL thickness measurements are similar and provide accurate classification of glaucomatous and healthy eyes. RVM may be preferable to SVM, because it provides a Bayesian-derived probability of glaucoma as an output. These results suggest that these machine learning classifiers show good potential for glaucoma diagnosis.
Corneal polarization axis (CPA) has been reported to affect retardation measurements obtained with scanning laser polarimetry (SLP). The purpose of this investigation was to prospectively determine ...whether correction for CPA improves the discriminating power of SLP for detection of mild-to-moderate glaucoma.
Cross-sectional analysis of normal and glaucomatous eyes.
We constructed a noninvasive slit-lamp-mounted device incorporating two crossed linear polarizers and an optical retarder to measure the slow axis of corneal polarization. Complete ocular examination, standard automated perimetry, SLP imaging, and CPA measurements were performed on normal and glaucomatous eyes. One eye/subject was enrolled; if both eyes of a patient were eligible for the study, the right eye was selected. For each of the 13 SLP parameters, logistic regression was used to determine if including CPA in the model influenced the ability to discriminate between normal and glaucomatous eyes.
Forty-three normal eyes (average visual field mean defect, -0.53 +/- 1.4 dB) and 33 glaucomatous eyes (average visual field mean defect, -5.93 +/- 6.5 dB) were enrolled. CPA was significantly correlated with summary retardation parameters (average thickness and integral values) in normal (r = 0.72-0.83, P <.001 for all values) and glaucomatous eyes (r = 0.43-0.62, P =.013 to <.001). Including CPA in the model improved the ability to discriminate between normal and glaucomatous eyes for five retardation parameters quantifying retinal nerve fiber layer (RNFL) thickness (range of P values: 0.045-0.001). For inferior average thickness, area under the receiver operating characteristic (ROC) curve increased significantly (P =.002) from 0.70 to 0.78 after accounting for CPA; with a sensitivity set at 80% specificity improved from 33% to 72%. Correlations between visual field corrected pattern standard deviation and average thickness, ellipse average, superior average, and inferior average significantly increased (range of P values,.018-.001) after adjustment for CPA (r = -0.35 and -0.45, -0.38 and -0.47, -0.46 and -0.57, and -0.42 and -0.49, respectively).
Correction for CPA significantly increases the correlation between retinal nerve fiber layer structural damage and visual function and significantly improves the discriminating power of SLP for detection of mild-to-moderate glaucoma.
The antimetabolite 5-fluorouracil (5-FU) was used as adjunctive treatment in glaucomatous eyes with poor prognoses undergoing filtering surgery. By adjusting the frequency of postoperative 5-FU ...subconjunctival injections according to the clinical response, the author thought it might be possible to reduce episcleral fibroproliferation and maintain a patent filter while reducing complications. Sixty-three eyes underwent filtering surgery with subsequent subconjunctival injections of 5.0 to 7.5 mg 5-FU for 14 days. The antimetabolite was not administered if there was evidence of corneal toxicity as demonstrated by epithelial defects or filaments, flat anterior chamber, or a conjunctival wound leak. By adjusting the injections in this fashion, the total amount of 5-FU administered ranged between 17.5 and 62.5 mg (34.4 +/- 11.6 mg). After 1 year, successful surgical outcomes were observed in 13/15 eyes with aphakia (87%), 11/17 eyes with neovascular glaucoma (65%), 11/12 eyes with at least two previous failed filters (92%), and 5/6 eyes with inflammatory glaucoma (83%). Eyes with epithelial downgrowth and cicatrizing diseases of the conjunctiva also were treated. Overall, conjunctival wound leaks were observed in 24% of the eyes and 29% had detectable changes in their corneal epithelium with corneal defects and filaments. Although adjusting the dose of 5-FU appears to be safe and effective, this can be determined clearly only by a controlled randomized clinical trial.
To determine the effect of bimatoprost on intraocular pressure in the prostaglandin FP receptor knockout mouse.
The IOP response to a single 1.2-microg (4 microL) dose of bimatoprost was measured in ...the treated and untreated fellow eyes of homozygote (FP+/+, n = 9) and heterozygote (FP+/-, n = 10) FP-knockout mice, as well as in wild-type C57BL/6 mice (FP+/+, n = 20). Serial IOP measurements were also performed after topical bimatoprost in a separate generation of homozygous FP-knockout mice and wild-type littermate control animals (n = 4 per group). Aqueous humor protein concentrations were measured to establish the state of the blood-aqueous barrier. Tissue, aqueous humor and vitreous concentrations of bimatoprost, latanoprost, and their C-1 free acids were determined by liquid chromatography and tandem mass spectrometry.
A significant reduction in IOP was observed in the bimatoprost-treated eye of wild-type mice at 2 hours, with a mean difference and 95% confidence interval (CI) of the difference in means of -1.33 mm Hg (-0.81 to -1.84). Bimatoprost did not lead to a significant reduction in IOP in either the heterozygous knockout -0.36 mm Hg (-0.82 to +0.09) or homozygous FP-knockout mice 0.25 mm Hg (-0.38 to +0.89). The lack of an IOP response in the FP-knockout mice was not a consequence of blood-aqueous barrier breakdown, as there was no significant difference in aqueous humor protein concentration between treated and fellow eyes. Tissue and aqueous humor concentrations of bimatoprost, latanoprost, and their C-1 free acids indicate that latanoprost, but not bimatoprost, is hydrolyzed in the mouse eye after topical administration.
An intact FP receptor gene is critical to the IOP response to bimatoprost in the mouse eye.
To examine the relationship between retinal nerve fiber layer (RNFL) measurements obtained using scanning laser polarimetry with variable corneal compensation and corneal thickness measurements in ...ocular hypertension (OHT) patients.
Observational cross-sectional study.
The study included 1 eye each from 44 OHT patients and 48 healthy subjects, all of similar age. All subjects had normal optic discs and normal standard automated perimetry (SAP) visual fields. Ocular hypertension patients had intraocular pressure (IOP) measurements higher than 22 mmHg.
All patients underwent imaging with the GDx VCC (Laser Diagnostic Technologies, Inc., San Diego, CA) scanning laser polarimeter. We examined the relationship between GDx VCC RNFL measurements and central corneal thickness, a risk factor for development of visual field loss among OHT patients. We also examined the relationship of GDx VCC measurements and age, IOP, SAP pattern standard deviation, and vertical cup-to-disc ratio.
Central corneal thickness (CCT) and GDx VCC RNFL thickness parameters.
Central corneal thickness measurements in OHT patients were significantly higher than those in healthy subjects (575+/-30 microm vs. 555+/-32 microm; P = 0.002). Higher GDx VCC parameter nerve fiber indicator (NFI) scores, indicating thinner RNFL, were correlated significantly with thinner CCT measurements in OHT patients (r = -0.502; P = 0.001). Ocular hypertension patients with thinner corneas (n = 22; mean CCT, 553+/-21 microm) had significantly higher NFI scores than OHT patients with thicker corneas (n = 22; mean CCT, 598+/-18 microm) and healthy control subjects (NFI mean +/- standard deviation, 26.9+/-9.5, 20.7+/-9.8, and 19.7+/-7.0, respectively; P = 0.004, analysis of variance). The NFI values were not significantly different between OHT patients with thicker corneas and healthy subjects. In multivariate analysis, only age and CCT measurement were associated significantly with GDx VCC RNFL measurements in OHT eyes.
Ocular hypertension patients with thinner corneas had significantly thinner RNFL than OHT patients with thicker corneas and healthy control subjects. These findings support the notion that RNFL defects as assessed by the GDx VCC may represent early glaucomatous damage in OHT eyes.
To assess the early effect of latanoprost on outflow facility and aqueous humor dynamics in the mouse.
Aqueous humor dynamics in NIH Swiss White mice were assessed with an injection and aspiration ...system, using fine glass microneedles. A single 200-ng (4 microL) dose of latanoprost was applied to one eye 2 hours before measurement. The fellow eye served as a control. Intraocular pressure (IOP) was measured by using an established microneedle procedure. Outflow facility (C) was determined by constant-pressure perfusion measurements obtained at two different IOPs. Aqueous humor flow (Fa) was determined by a dilution method using rhodamine-dextran. Conventional and uveoscleral outflow (Fc and Fu) were calculated by the Goldmann equation.
Average IOP, Fa, and C of control eyes were 15.7 +/- 1.0 mm Hg, 0.144 +/- 0.04 microL/min (mean +/- SD, n = 8), and 0.0053 +/- 0.0014 microL/min per mm Hg (n = 21), respectively. Average IOP, Fa, and C of treated eyes were 14.0 +/- 0.8 mm Hg, 0.138 +/- 0.04 microL/min (n = 8 for each), and 0.0074 +/- 0.0016 microL/min per mm Hg (n = 21), respectively. The differences between treated and control eyes were significant for IOP and total outflow facility only.
These data indicate that the early hypotensive effect of latanoprost in the mouse eye is associated with a significant increase in total outflow facility. Alterations in the aqueous dynamics induced by latanoprost can be measured reproducibly in the mouse and may provide a useful model for further determining the mechanism by which latanoprost reduces IOP and alters outflow facility.
We cross-sectionally examined the relationship between age, optic disc area, refraction, and gender and optic disc topography and retinal nerve fiber layer (RNFL) measurements, using optical imaging ...techniques. One eye from each of 155 Caucasian subjects (age range 23.0-80.8 y) without ocular pathology was included. Measurements were obtained by using the Heidelberg Retina Tomography (HRT), the GDx Nerve Fiber Analyzer, and the Optical Coherence Tomograph (OCT). The effects of age were small (R2 < 17%) and were limited to specific HRT, GDx, and OCT parameters. Disc area was significantly associated with most HRT parameters and isolated GDx and OCT parameters. Refraction and gender were not significantly associated with any optic disc or RNFL parameters. Although effects of age on the optic disc and RNFL are small, they should be considered in monitoring ocular disease. Optic disc area should be considered when cross-sectionally evaluating disc topography and, to a lesser extent, RNFL thickness.
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