Morphologic and Cellular Changes Induced by Selective Laser Trabeculoplasty.

Purpose: Selective laser trabeculoplasty is a safe and effective procedure for reducing IOP, but its mechanism of action is not fully elucidated. We evaluated the morphologic and cellular changes as well as DNA synthesis after SLT treatment of human trabecular meshwork (TM) tissue explants. Methods: Corneoscleral rim tissues that underwent SLT treatment were compared to control segments that had no laser treatment. Light microscopy (LM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were used to assess cell morphology. The Click-iT 5-ethynyl-2'-deoxyuridine (EdU) imaging kit was used to compare DNA synthesis/cell proliferation with a confocal microscope. All tissues were assessed for vitality. Results: SLT treatment does not reveal notable cell damage in the juxtacanalicular (JCT) region, but mildly disrupts superficial trabecular beams and uveal TM, ablates TM endothelial cells from the undamaged beams as detected by both LM and TEM. This superficial destruction was not observed in some SLT treatment spots on higher magnification by SEM. SLT treatment increased mitotic activity and DNA synthesis near the lining of Schlemm's canal after several days. Conclusion: SLT treatment disrupts endothelial cells in the corneoscleral TM and causes superficial ultrastructural changes to the uveal TM. SLT treatment also shows a trend towards dynamic time-dependent changes in (DNA synthesis) with an increase in mitotic activity at 7 days cell proliferation.

Low-energy Selective Laser Trabeculoplasty Repeated Annually: Rationale for the COAST Trial.

The recent Laser in Glaucoma and Ocular Hypertension Trial provided the evidentiary basis for a paradigm shift away from the historical medication-first approach to glaucoma--which has numerous limitations, the most important of which is poor adherence to therapy --and toward a laser-first approach. Now 20 years after its commercialization, selective laser trabeculoplasty (SLT) is routinely performed consistently with its initial description, with energy titrated to the appearance of fine, champagne-like cavitation bubbles. A recent data set suggested that lower energy SLT, applied as primary therapy and repeated annually irrespective of intraocular pressure--rather than pro re nata when its effect wanes and irrespective of intraocular pressure rises --yields longer medication-free survival than standard energy SLT repeated pro re nata. A new study--Clarifying the Optimal Application of SLT Therapy --has been initiated to explore this preliminary finding in a pair of consecutive randomized trials. Herein, we provide an evidence-based rationale for the use of low-energy SLT repeated annually as primary therapy for mild to moderate primary open-angle glaucoma or high-risk ocular hypertension.

Orbital leiomyosarcoma metastasis presenting prior to diagnosis of the primary tumor.

Leiomyosarcomas, neoplasms of smooth muscle, are rarely found within the orbit. Orbital leiomyosarcoma may be primary, metastatic, or secondary to radiation. When they are metastatic, patients almost exclusively have a history of a primary leiomyosarcoma, often occurring in the spermatic cord, skin, gastrointestinal tract, or the uterus. We present the case of 48-year-old woman who presented with a metastatic orbital leiomyosarcoma, which was identified before the primary tumor.

The use of anterior segment imaging after trabeculectomy.

Evaluation of patients after trabeculectomy can be aided by the use of anterior segment imaging. Two commonly used forms of imaging are ultrasound biomicroscopy (UBM) and optical coherence tomography (OCT). Both modalities can be used to assess bleb morphology and how it affects treatment outcome, measure anterior chamber biometry, identify the presence of supraciliochoroidal fluid, cyclodialysis clefts and malignant glaucoma, and evaluate treatment modalities after trabeculectomy such as in laser suture lysis and needling. OCT, with its finer resolution, is able to view the bleb wall anatomy in detail and because of its non-contact nature can examine the eye sooner after trabeculectomy. UBM, on the other hand, is superior for the visualization of deeper structures such as the ciliary body and posterior chamber essential to identify malignant glaucoma.

Effect of central corneal thickness on the long-term outcome of selective laser trabeculoplasty as primary treatment for ocular hypertension and primary open-angle glaucoma.

PURPOSE: To determine if central corneal thickness (CCT) impacts the intraocular pressure (IOP)-lowering effect of selective laser trabeculoplasty (SLT) in patients with ocular hypertension (OHT) and primary open-angle glaucoma (POAG). METHODS: A retrospective chart review of consecutive patients, who underwent SLT as primary treatment for OHT and POAG, between 2002 and 2005, was performed. Partial correlation analysis was performed to correlate the CCT to the percentage of IOP reduction at 3 to 30 months after SLT. Independent samples t test was performed to compare mean percentage of IOP reduction in eyes with CCT less than 555 µm versus CCT 555 µm or greater. RESULTS: Eighty eyes of 47 patients were identified. The partial correlation coefficient value between the CCT and percentage of IOP reduction after SLT at 3 months was -0.253 (P = 0.025), at 12 months it was -0.22 (P = 0.049), and at 30 months it was 0.301 (P = 0.007). Independent samples t test showed that the mean percentage of IOP reduction in eyes with thinner corneas (CCT < 555 µm) was greater than that in thicker corneas (CCT ≥ 555 µm) at 3-, 6-, 9-, 12-, and 30-month post-SLT (P < 0.05). CONCLUSIONS: In patients with POAG and OHT, percentage of IOP reduction after SLT was significantly greater in eyes with thinner corneas (CCT < 555 µm). These findings indicate that patients treated with SLT as primary therapy who had thinner corneas demonstrated better IOP control for at least 30 months after SLT.

Use of processed pericardium graft to plug patulous old sclerostomy track during glaucoma shunt revision for exposure.

The authors demonstrate a reproducible technique using processed pericardium to seal sclerostomy track during glaucoma shunt revision. The suggested method involves placement of a wedge-shaped processed pericardial graft into the old sclerostomy tract following tube explantation. The graft is trimmed and sutured to the sclera. The tube is reinserted into a new sclerostomy and then sutured in place and covered in the usual fashion. This method allowed relatively easy treatment of three patients with patulous sclerostomy with necrotic edges. A successful tube revision and repositioning of the tube using this technique was performed on three patients with exposed tubes. The intraocular pressure was between 8 and 12 mm Hg from postoperative day 1. The authors suggest the use of pericardium plug to adequately seal the old sclerostomy track during glaucoma shunt revision. The plug allows tube repositioning at a new site without the need to suture the friable sclerostomy edges.

Autoimmune basis of glaucoma.

Glaucoma is one of the leading causes of blindness worldwide. The current view of glaucoma is that it is a multifactorial disease. Elevated IOP is a recognized etiologic factor which can trigger initial damage through biomechanical and ischemic injury to the retinal ganglion cells. However, elevated intraocular pressure cannot be entirely responsible for the development of glaucoma. Accumulating evidence suggests that abnormal immunity may be contributing to the glaucomatous optic neuropathy. Autoimmunity may be responsible for initiating or exacerbating glaucoma. This review provides an evaluation of the potential role of autoimmunity in some patients with glaucoma.

Posner-Schlossman glaucomatocyclitic crisis.

In 1948, Posner and Schlossman first reported glaucomatocyclitic crisis, an uncommon form of glaucoma characterized by recurrent unilateral episodes of markedly elevated intraocular pressure (IOP) with mild idiopathic anterior chamber inflammation. The exact etiology of glaucomatocyclitic crisis is not clear. Although it is typically a self-limited condition, some cases with advanced optic nerve cupping and associated visual field loss have been reported. Diagnosis of Posner-Schlossman syndrome is difficult, and it may mimic a variety of ocular disorders. Treatment of this syndrome is directed towards controlling the inflammation and associated IOP elevation.

Intraocular pressure response to selective laser trabeculoplasty in the first treated eye vs the fellow eye.

OBJECTIVE: To determine if the intraocular pressure (IOP) response to selective laser trabeculoplasty (SLT) in one eye predicts long-term response to SLT in the fellow eye. METHODS: A retrospective medical record review was performed of patients who underwent SLT as primary treatment in both eyes and who completed at least 30 months of follow-up visits. Pearson product moment correlation analysis was performed to determine correlations between the 3-month percentage of IOP reduction in the first treated eye and long-term percentages of IOP reduction in the fellow eye. RESULTS: Medical records of 80 eyes in 40 patients were reviewed. In patients with ocular hypertension, the 3-month percentage of IOP reduction in the first treated eye correlated strongly with long-term percentages of IOP reduction in the fellow eye (r > 0.652). In patients with primary open-angle glaucoma, the 3-month percentage of IOP reduction in the first treated eye correlated moderately with percentages of IOP reduction in the fellow eye up to 9 months (r > 0.367). CONCLUSIONS: In patients with ocular hypertension, the 3-month percentage of IOP reduction in the first treated eye in response to SLT was predictive of response in the fellow eye up to 30 months. In patients with primary open-angle glaucoma, the 3-month percentage of IOP reduction in the first treated eye in response to SLT was predictive of response in the fellow eye up to 9 months.

Comparison of intraocular pressure-lowering effect of every night versus every other night dosing of bimatoprost 0.03%.

PURPOSE: To compare intraocular pressure (IOP) reduction profiles of bimatoprost 0.03% administered every other night (QOD-HS) compared with every night (QHS) in patients with primary open angle glaucoma and pseudoexfoliation glaucoma. METHODS: A retrospective chart review of 68 eyes of 45 consecutive patients who were switched from QHS to QOD-HS bimatoprost due to intolerable conjunctival hyperemia between May 2005 and May 2008. IOP in the morning (AM) and afternoon (PM) of the next day after administration (day 1) and the day after (day 2) on QOD-HS regimen was compared with IOP in the AM and PM when they were on QHS regimen, 4-6 weeks after switching to QOD-HS. RESULTS: Mean IOPs on QHS bimatoprost were 15.9±3.4 mm Hg in the AM and 15.5±2.7 mm Hg in the PM, whereas mean IOPs on QOD-HS were 14±2 mm Hg (AM) and 14.2±2.5 mm Hg (PM) on day 1, and 14.7±2.6 mm Hg (AM) and 14.4±2.4 mm Hg (PM) on day 2 after administration. Differences between IOP fluctuation on QHS and QOD-HS days 1 and 2, respectively, were not significant (P=0.87 and 0.94). CONCLUSION: Every other night dosing of bimatoprost was effective in controlling IOP in this select group of patients with primary open angle glaucoma and pseudoexfoliation glaucoma who had troublesome side effects on bimatoprost 0.03% QHS regimen, and may be considered as an alternative to every day treatment.

Effect of prior cataract surgery on the long-term outcome of selective laser trabeculoplasty.

OBJECTIVE: To determine if pseudophakia affects selective laser trabeculoplasty (SLT) intraocular pressure (IOP) lowering effect. METHODS: A retrospective chart review was performed on 94 eyes of 75 consecutive patients who underwent SLT as primary treatment for ocular hypertension and primary open-angle glaucoma between 2002 and 2005 and completed at least 30 months follow up. Patients were excluded if they required additional glaucoma medications, laser, or ocular surgery during the follow-up period. Patients were categorized as phakics or pseudophakics. Independent-samples t-test was performed to compare the mean percentage of IOP reduction at 3, 6, 12, 18, and 30 months after SLT between the phakic and pseudophakic groups. RESULTS: Seventy-six phakic and 18 pseudophakic eyes were included. IOP reduction in phakic group was 27.4% (2 week), 29.8% (3 months), 27.7% (9 months), 27.4% at (12 months) and 27.3% at (30 months). In pseudophakic patients, the mean IOP reduction was 19.8% (2 weeks), 26.5% (3 months), 23.2% (9 months), 22.5% (12 months), and 25.9% (30 months). An independent-sample t-test compared the percentage of IOP reduction between the phakic and pseudophakic groups and revealed higher percentage of IOP reduction in the phakic group at 2 weeks by 7.6% (P = 0.01). P value for difference was 0.34 (3 months), 0.25 (6 months), 0.18 (9 months), 0.12 (12 months), 0.36 (18 months), and 0.7 (30 months) after SLT. CONCLUSIONS: SLT response was delayed in pseudophakic compared to phakic patients, while the long-term effectiveness of SLT is the same in both groups.

Long-term safety and efficacy of selective laser trabeculoplasty as primary therapy for the treatment of pseudoexfoliation glaucoma compared with primary open-angle glaucoma.

PURPOSE: To investigate the safety and efficacy of selective laser trabeculoplasty (SLT) to reduce intraocular pressure (IOP) in patients with pseudoexfoliation glaucoma (PXFG) compared with primary open-angle glaucoma (POAG). DESIGN: Non-randomized, prospective, clinical trial. METHODS: Nineteen eyes of 13 patients with POAG and 18 eyes of 13 patients with PXFG were treated with SLT. Patients were followed without antiglaucoma medications until additional medical, laser, or surgical intervention was initiated, at which time they were considered failures, had withdrawn from the study, or underwent a second SLT. RESULTS: The POAG and PXFG eyes showed similar reductions of IOP over the 49 months of follow-up. At 30 months of follow-up the POAG group showed a mean IOP of 17.6 ± 2.8 mmHg and a mean IOP reduction of 5.7 ± 2.1 mmHg; the PXFG group showed a mean IOP of 18.3 ± 4.7 and a mean IOP reduction of 5.3 ± 3.0 mmHg. Four eyes in the PXFG group and three eyes in the POAG group failed by 30 months. The cumulative probability of success was 74% for the PXFG group and 77% for the POAG group. Four PXFG eyes underwent a second SLT after 30 months of follow-up with a final IOP of 17.6 ± 2.8 mmHg. There were no serious adverse events. CONCLUSION: SLT is a safe and effective method to lower IOP in patients with PXFG as initial glaucoma therapy. Both groups showed similar IOP reductions and failure rates.

Imaging of optic nerve head drusen: improvements with spectral domain optical coherence tomography.

OBJECTIVE: To demonstrate a new algorithm that can determine the shape, location, and volume of optic nerve head drusen (ONHD), which were imaged with spectral domain optical coherence tomography (SDOCT). METHODS: One exenteration patient and 4 glaucoma patients with bilateral ONHD were recruited from the Massachusetts Eye and Ear Infirmary and from a private practice office. Images were obtained using an experimental SDOCT system developed at the Wellman Center for Photomedicine, Massachusetts General Hospital. With axial resolutions of about 6 mum, SDOCT can obtain 2-dimensional images in 1/29 of a second, compared with commercially available time domain OCT instruments with 10 mum resolution images in 1.28 seconds. The volumes of ONHD were calculated with a new algorithm and were then correlated with visual field mean deviation. RESULTS: SDOCT can display 2-dimensional images comparable with histology and 3-dimensional videos of ONHD. ONHD are signal-poor regions with high-signaled borders. Larger ONHD volumes are directly correlated with larger mean deviation absolute values on Humphrey visual field testing. CONCLUSIONS: SDOCT is a potentially better technique for ONHD imaging and may improve the diagnosis and management of patients with both OHND and glaucoma.

Neovascular glaucoma: etiology, diagnosis and prognosis.

Neovascular glaucoma (NVG) is a severe form of glaucoma with devastating visual outcome attributed to new blood vessels obstructing aqueous humor outflow, usually secondary to widespread posterior segment ischemia. Invasion of the anterior chamber by a fibrovascular membrane initially obstructs aqueous outflow in an open-angle fashion and later contracts to produce secondary synechial angle-closure glaucoma. The full blown picture of NVG is characterized by iris neovascularization, a closed anterior chamber angle, and extremely high intraocular pressure (IOP) with severe ocular pain and usually poor vision.

A comparison of the intervisit intraocular pressure fluctuation after 180 and 360 degrees of selective laser trabeculoplasty (SLT) as a primary therapy in primary open angle glaucoma and ocular hypertension.

OBJECTIVE: To determine and compare the effect of 180 and 360 degrees of selective laser trabeculoplasty (SLT) treatment as a primary therapy on the intervisit intraocular pressure (IOP) fluctuation in patients followed up for a period of 2 years without any further medical or surgical intervention. METHODS: Retrospective chart review of patients with ocular hypertension and primary open angle glaucoma who received SLT as primary therapy without any subsequent medical or surgical intervention. IOP before SLT and postlaser IOP at all the visits during the follow-up period of months 6 to 24 was determined. The standard deviation (SD) of the mean IOP was used as a surrogate for IOP fluctuation. RESULTS: Forty-one eyes were treated by SLT, 19 eyes in the 180-degree group and 22 eyes in the 360-degree group. The mean reduction in IOP at 2 years was 28% in 180-degree group and 35% in 360-degree SLT group. After the SLT, the 360-degree SLT group had a lower IOP fluctuation compared with the 180-degree SLT group over the follow-up period of months 6 to 24. The percentage of eyes with intervisit IOP fluctuation (SD)

Low Power Laser Irradiation Stimulates the Proliferation of Adult Human Retinal Pigment Epithelial Cells in Culture.

We investigated the effects of low power laser irradiation on the proliferation of retinal pigment epithelial (RPE) cells. Adult human RPE cells were artificially pigmented by preincubation with sepia melanin, and exposed to a single sublethal laser pulse (590 nm, 1 µs, <200 mJ/cm2). DNA synthesis, cell number, and growth factor activity in irradiated RPE cells were subsequently monitored. The effect of sublethal laser irradiation on the "wound" healing response of an RPE monolayer in an in vitro scratch assay was also investigated. Single pulsed laser irradiation increased DNA synthesis in pigmented RPE cells measured 6 h post-treatment. In the scratch assay, laser irradiation increased the rates of cell proliferation and wound closure. Conditioned medium, collected 48 h following laser treatment, increased cell proliferation of unirradiated cells. Irradiation increased RPE cell secretion of platelet-derived growth factor (PDGF)-B chain, and increased mRNA levels of several growth factors and their receptors, including PDGF, transforming growth factor-ß1, basic fibroblast growth factor, epidermal growth factor, insulin-like growth factor, as well as heat shock proteins. This demonstrates, for the first time, that low power single pulsed laser irradiation stimulates the proliferation of RPE cells, and upregulates growth factors that are mitogenic for RPE cells.

Glaucoma in retinoblastoma.

The association between retinoblastoma and secondary glaucoma is well known. The most common cause of secondary glaucoma in retinoblastoma is iris neovascularization (NVI) followed by pupillary block and tumor seeding of the anterior chamber. Although glaucoma is a secondary clinical issue in retinoblastoma (RB) management and care, awareness of its presence, revealed by a thorough ocular exam of the anterior segment, can guide the clinician in assessing the overall condition of the affected eye.