Evidence-Based Consensus Guidelines Series for MicroPulse Transscleral Laser Therapy - Surgical Technique, Post-Operative Care, Expected Outcomes and Retreatment/Enhancements.

Purpose: To provide expert consensus and evidence-based current guidelines on treatment technique, postoperative care, expected outcomes and retreatment for MicroPulse Transscleral Laser Treatment (TLT). Methods: A comprehensive search of PubMed led to the identification and analysis of 61 studies on MicroPulse TLT. To provide guidance in areas where there was not enough available literature, a three-round Delphi method was conducted involving 10 international experts in MicroPulse TLT. Results: The response rate was 70% in the first round, 70% in the second round, and 80% in the third round of the Delphi method. Once all responses were aggregated, a live meeting was held with 90% attendance, and consensus was achieved on each of the findings detailed in this manuscript. Conclusion: Used within appropriate treatment parameters, with proper technique and patient selection, MicroPulse TLT is a safe and effective treatment for many types and severities of glaucoma. MicroPulse TLT represents a useful addition to the glaucoma armamentarium.

Evidence-Based Consensus Guidelines Series for MicroPulse Transscleral Laser Therapy: Dosimetry and Patient Selection.

Purpose: To provide consensus-based current guidelines on optimal dosimetry and patient selection for MicroPulse Transscleral Laser Therapy (TLT) based on a review of the literature and a Delphi method. Methods: A comprehensive search of Pub Med led to the identification and analysis of 61 studies on MicroPulse TLT that contained information on laser settings and patient selection. To determine consensus in areas where there was not enough available literature, a three-round Delphi method was conducted. Results: The response rate was 90% in the first round, 90% in the second round, and 80% in the third round of the Delphi technique. Once all responses were aggregated, a live meeting was held with 80% attendance, and consensus was achieved on each of the findings detailed in this manuscript. Conclusion: Micropulse TLT is a useful addition to the glaucoma armamentarium. When used with proper surgical technique at energy settings within the boundaries described in this manuscript, MicroPulse TLT is a safe and effective treatment for many types and stages of glaucoma. Based on current knowledge and experience, the consensus recommendation of this expert panel is that the standard MicroPulse TLT settings using the revised MicroPulse P3 Probe should be 2500 mW, 31.3% duty cycle, and 4 sweeps at a sweep velocity of 20 seconds each per hemisphere. Both hemispheres avoiding the 3 and 9 clock hours should be treated. The panel also reached consensus on patient selection for MicroPulse TLT providing guidance for the use of the procedure.

MicroPulse® Transscleral Laser Therapy - Fluence May Explain Variability in Clinical Outcomes: A Literature Review and Analysis.

Since the first peer-reviewed publication on MicroPulse® Transscleral Laser Therapy (MP-TLT) in 2010, authors worldwide have used a wide range of treatment parameter combinations with varying clinical efficacy in terms of the magnitude of intraocular pressure reduction, success rate, durability, and safety profile. This has made it difficult to determine the proper parameters necessary to optimize efficacy and safety, and has made comparison of results from one investigation to another difficult. The first goal of this paper is to explain and highlight the impact of the choices of exposure time and the number of sweeps per hemisphere in terms of "sweep velocity" on energy delivery to the eye. These treatment parameters are underreported in the literature. The second goal is to introduce fluence as a "dose" metric, that combines all the treatment parameters and constants into a single number. Fluence may be a better light-dose metric and a more reliable indicator of clinical outcomes compared to total energy.

Excisional goniotomy with Kahook Dual Blade in a patient with glaucoma secondary to Transthyretin Amyloidosis.

PURPOSE: To report for the first time the successful use of the Kahook Dual Blade excisional goniotomy technique in a patient with Transthyretin Amyloidosis. PATIENT AND METHODS: The Kahook Dual Blade is a single use ab interno trabeculectomy device that removes the trabecular meshwork reducing aqueous humor outflow resistance. A patient with Transthyretin Amyloidosis underwent this procedure. RESULTS: Ab interno goniotomy with Kahook Dual Blade was a successful surgical solution to reduce intraocular pressure in a patient with Transthyretin Amyloidosis secondary glaucoma controlling IOP in association with topical hypotensors for at least 6 months. CONCLUSIONS: Ab interno goniotomy with Kahook Dual Blade is a surgical option for this type of glaucoma, that treats the main site of aqueous outflow resistance in this pathology with the advantage of being minimally invasive.

Update on Micropulse Transscleral Cyclophotocoagulation.

Micropulse transscleral cyclophotocoagulation is a promising and relatively new technique that uses repetitive micropulses of diode laser energy, delivered with the Cyclo G6 Glaucoma Laser System (Iridex Corporation), in an off-and-on cyclical manner. This review article provides an update on the latest data available for this technique, including a discussion of the aspects in which there is still limited data, such as the precise mechanism of action, the ideal laser parameters based on total energy levels, as well as an overview of other potentially relevant variables that may be playing an important role in outcomes.

Micropulse Transscleral Cyclophotocoagulation: A Hypothesis for the Ideal Parameters.

MicroPulse transscleral cyclophotocoagulation (IRIDEX Corp., Mountain View, CA) is a novel technique that uses repetitive micropulses of active diode laser (On cycles) interspersed with resting intervals (Off cycles). It has been proposed that the OFF cycles allow thermal dissipation and, therefore, reduce collateral damage. The literature suggests that Micropulse has a better safety profile compared to traditional continuous-wave cyclophotocoagulation. However, because it is a relatively new technique, there are no clear guidelines stating the ideal laser parameters that would allow the best balance between high and sustained effectiveness with minimal side effects. This research reviewed the literature to approximate ideal parameters for single-session treatment. To simplify the comparison between studies, this study used Joules (J) as a way to standardize the energy levels employed. The reviewed clinical publications allowed reduction of these parameters to a range between 112 and 150 J of total energy, which allows a moderate IOP lowering effect of around 30% with few/no complications. An additional narrowing of the parameters was achieved after analyzing recently published experimental data. These data suggest a different mechanism of action for the Micropulse, similar to that of the pilocarpine. This effect was maximum at 150 J. Since clinical studies show few or no complications, even at those energy levels, it could be hypothesized that the ideal parameters can be located at a point closer to 150 J. This data also leads to the concept of dosimetry; the capacity to dose mTSCPC treatment based on desired IOP lowering effect and risk exposure. Further prospective studies are needed to test the proposed evidence-based hypothesis.

Twenty-four-hour pattern of intraocular pressure in untreated patients with ocular hypertension.

PURPOSE: To characterize the 24-hour pattern of intraocular pressure (IOP) in untreated ocular hypertensive (OHTN) patients. METHODS: IOP measurements were taken every 2 hours during a 24-hour period from 15 untreated OHTN patients (ages 41-77 years). Measurements were both sitting and supine (diurnal) and supine only (nocturnal). Mean diurnal and nocturnal IOPs in the OHTN group were compared to previously reported values in age-matched healthy and glaucomatous eyes. Post hoc analysis compared the 24-hour IOP pattern of the OHTN patients who converted to glaucoma and those who did not with that in the same healthy and glaucomatous eyes. RESULTS: Mean sitting and supine IOPs were significantly higher in the OHTN group than in the healthy control but not the glaucoma group. Similar to the glaucoma group, the OHTN group demonstrated significant differences from healthy controls in diurnal IOP variation and IOP changes upon awakening in habitual and supine positions. The 24-hour IOP curve acrophases and amplitudes for OHTNs were closer to those of the glaucoma than the healthy control group in the habitual position. Thirty-three percent of OHTNs developed glaucoma during a mean follow-up period of 4.3 ± 3.8 years. Similar to findings in the glaucoma group, habitual IOP curve phase delay, habitual IOP variation, diurnal-to-nocturnal IOP changes, and IOP changes upon awakening of the converters were significantly different from those in healthy controls. There were no differences between nonconverters and other groups. CONCLUSIONS: Baseline 24-hour IOP pattern in OHTN patients is similar to that in glaucomatous patients. In contrast to nonconverters, OHTN patients who converted to glaucoma are significantly different from healthy controls.

Changing trends of imaging in angle closure evaluation.

Primary angle closure glaucoma (PACG) is a significant cause of visual disability worldwide. It predominantly affects the Eastern and South Asian population of the world. Early detection of anatomically narrow angles is important, and the subsequent prevention of visual loss from PACG depends on an accurate assessment of the anterior chamber angle (ACA). Gonioscopy has given way to modern day imaging technologies such as ultrasound biomicroscopy (UBM) and more recently, anterior segment optical coherence tomography (AS-OCT). Ultrasound biomicroscopy provides objective, high-resolution images of anterior segment anatomy, including the cornea, iris, anterior chamber, anterior chamber angle, and ciliary body. Optical coherence tomography (OCT) is a noncontact optical signal acquisition and processing device that provides magnified, high-resolution cross-sectional images of ocular tissues. Recent technological advances towards three-dimensional visualization broadened the scope of AS-OCT in ophthalmologic evaluation. Optical coherence tomography systems use low-coherence, near-infrared light to provide detailed images of anterior segment structures at resolutions exceeding that of UBM. This paper summarizes the clinical application of UBM and OCT for assessment of anterior segment in glaucoma.

Serious complications of cosmetic NewColorIris implantation.

PURPOSE: This case report describes serious postoperative complications and markedly elevated intraocular pressure (IOP) associated with the NewColorIris cosmetic implant. METHODS: We report an interventional case series of two patients who suffered multiple complications after NewColorIris implantation carried out in Panama. Assessment included visual acuity, photography, endothelial cell count and anterior segment optical coherence tomography (OCT) when possible. RESULTS: Both patients presented with endothelial cell loss, uveitis, pigment dispersion and elevated IOP. Anterior segment OCT demonstrated irregularities in the position and configuration of the implants within the anterior chamber with resultant areas of implant-iris and implant-endothelial contact. One patient had acute postoperative hyphaema that resolved with anterior chamber tissue plasminogen activator injection. Both patients required explantation OU, one eye has required trabeculectomy, and one eye with bullous keratopathy is being evaluated for Descemet's stripping endothelial keratoplasty. CONCLUSIONS: Implantation of the NewColorIris cosmetic implant can lead to serious complications including hyphaema, uncontrolled IOP, severe endothelial cell loss, bullous keratopathy and anterior uveitis. Explantation may lead to improvement, but permanent damage to the trabecular meshwork and corneal endothelium persists.

The effects of optic disc drusen on the latency of the pattern-reversal checkerboard and multifocal visual evoked potentials.

PURPOSE: To determine the effect of optic disc drusen on the latency of the pattern-reversal checkerboard visual evoked potentials (VEPs) and multifocal (mf)VEPs and to better understand the pathophysiology of the condition. METHODS: Eighteen eyes with optic disc drusen (10 patients) and 38 control eyes (19 subjects) underwent VEP, mfVEP, and visual field testing. Only one eye of each individual, the one with the more affected visual field, was used in the analyses. The VEPs were recorded with a 15' and 60' reversing checkerboard pattern, and the mfVEPs were elicited by a 60-sector dartboard display. RESULTS: Unlike the VEP results, the mfVEP revealed a significant increase in the average monocular latency of the optic disc drusen group compared with that of the control group. The average mfVEP relative latency for the optic disc drusen group (4.1 ms) was greater than that (0.8 ms) in the control group. For monocular and interocular analyses, the average percentage of points delayed in the drusen group was significantly greater than that in the control group. CONCLUSIONS: Optic disc drusen produced significant latency delays on the mfVEP test but not on the VEP test, presumably due to the mfVEP's ability to detect the effects of local changes. The results are consistent with the hypothesis that local mechanical compression by optic disc drusen leads to abnormal retinal ganglion cell activity.

A method to detect progression of glaucoma using the multifocal visual evoked potential technique.

PURPOSE: To describe a method for monitoring progression of glaucoma using the multifocal visual evoked potential (mfVEP) technique. METHODS: Eighty-seven patients diagnosed with open-angle glaucoma were divided into two groups. Group I, comprised 43 patients who had a repeat mfVEP test within 50 days (mean 0.9 +/- 0.5 months), and group II, 44 patients who had a repeat test after at least 6 months (mean 20.7 +/- 9.7 months). Monocular mfVEPs were obtained using a 60-sector pattern reversal dartboard display. Monocular and interocular analyses were performed. Data from the two visits were compared. The total number of abnormal test points with P < 5% within the visual field (total scores) and number of abnormal test points within a cluster (cluster size) were calculated. Data for group I provided a measure of test-retest variability independent of disease progression. Data for group II provided a possible measure of progression. RESULTS: The difference in the total scores for group II between visit 1 and visit 2 for the interocular and monocular comparison was significant (P < 0.05) as was the difference in cluster size for the interocular comparison (P < 0.05). Group I did not show a significant change in either total score or cluster size. CONCLUSION: The change in the total score and cluster size over time provides a possible method for assessing progression of glaucoma with the mfVEP technique.

Optic nerve head drusen and visual field loss in normotensive and hypertensive eyes.

OBJECTIVE: To compare visual field loss (VFL) in eyes with optic nerve head drusen (ONHD) with or without ocular hypertension (OHT). METHODS: The records of all patients aged 45 years or older with a diagnosis of ONHD at 2 centers were reviewed. OHT was defined as intraocular pressure >or=22 mm Hg. We categorized ONHD into 3 grades based on visibility on disc photographs. RESULTS: We identified 22 eyes (13 patients) with both ONHD and OHT and 81 normotensive eyes (47 patients) with ONHD. VFL was present in 20/22 (90.9%) of hypertensive eyes compared with 54/81 (66.7%) of normotensive eyes (P=0.03, Fisher exact test). Drusen grade III and OHT were both independently and significantly associated with greater incidence of VFL (logistic regression analysis). CONCLUSIONS: VFL occurs more frequently in eyes with ONHD that also have OHT. Eyes with grade III ONHD are at increased risk for VFL compared to eyes with grade I drusen with the same intraocular pressure status. Patients with OHT and ONHD should undergo close surveillance for disease progression and be treated appropriately to prevent additional VFL.

A comparison of multifocal and conventional visual evoked potential techniques in patients with optic neuritis/multiple sclerosis.

PURPOSE: To compare conventional visual evoked potential (cVEP) and multifocal visual evoked potential (mfVEP) methods in patients with optic neuritis/multiple sclerosis (ON/MS). METHODS: mfVEPs and cVEPs were obtained from eyes of the 19 patients with multiple sclerosis confirmed on MRI scans, and from eyes of 40 normal controls. For the mfVEP, the display was a pattern-reversal dartboard array, 48 degrees in diameter, which contained 60 sectors. Monocular cVEPs were obtained using a checkerboard stimulus with check sizes of 15' and 60'. For the cVEP, the latency of P100 for both check sizes were measured, while for the mfVEP, the mean latency, percent of locations with abnormal latency, and clusters of contiguous abnormal locations were obtained. RESULTS: For a specificity of 95%, the mfVEP(interocular cluster criterion) showed the highest sensitivity (89.5%) of the 5 monocular or interocular tests. Similarly, when a combined monocular/interocular criterion was employed, the mfVEP(cluster criterion) had the highest sensitivity (94.7%)/specificity (90%), missing only one patient. The combined monocular/interocular cVEP(60') test had a sensitivity (84.2%)/specificity (90%), missing 3 patients, 2 more than did the monocular/interocular mfVEP(cluster) test. CONCLUSION: As the cVEP is more readily available and currently a shorter test, it should be used to screen patients for ON/MS with mfVEP testing added when the cVEP test is negative and the damage is local.

Canalopatías en pediatría: hemiplejías episódicas / Channelpathies in pediatrics: episodic hemiplegias

Introducción. Los canales iónicos reconocen y seleccionanespecíficamente el intercambio iónico.Sus alteraciones (canalopatías) representan cuadros clínicos variados, continuos o progresivos. Hemiplejía alternante: de carácter progresivo se presenta en la infancia con hipotonía menos distonía, movimientos anormales de los ojos y nistagmus. Está asociada a hemiplejía alternante y fenómenos autonómicos.Los síntomas desaparecen con el sueño. Los períodos de latencia entre crisis son variables, pero hay peoría del cuadro con la edad. Existen alteracionesfocales del flujo sanguíneo. A nivel molecular es probable una mutación del gen ATP1A2. La flunarizinay el topiramato pueden mejorar los ataques, aunque no evitan la progresión del cuadro. Migraña hemipléjica familiar: se caracteriza por trastornos visuales y sensoriales, asociados a alteraciones motoras (hemiparesia) de duración variable y cefaleas. En el 80 por ciento hay restitución a la normalidad (MHF1) y en el 20 por ciento ataxia y deficiencia neurológica (MHF2). El gen involucrado es el CACNA1A, en el cromosoma 19 p13. La frecuencia e intensidad de los ataques mejoran con acetozolamiday antidepresivos β menos bloqueantes

Canalopatías en pediatría: hemiplejías episódicas / Channelpathies in pediatrics: episodic hemiplegias

Introducción. Los canales iónicos reconocen y seleccionanespecíficamente el intercambio iónico.Sus alteraciones (canalopatías) representan cuadros clínicos variados, continuos o progresivos. Hemiplejía alternante: de carácter progresivo se presenta en la infancia con hipotonía menos distonía, movimientos anormales de los ojos y nistagmus. Está asociada a hemiplejía alternante y fenómenos autonómicos.Los síntomas desaparecen con el sueño. Los períodos de latencia entre crisis son variables, pero hay peoría del cuadro con la edad. Existen alteracionesfocales del flujo sanguíneo. A nivel molecular es probable una mutación del gen ATP1A2. La flunarizinay el topiramato pueden mejorar los ataques, aunque no evitan la progresión del cuadro. Migraña hemipléjica familiar: se caracteriza por trastornos visuales y sensoriales, asociados a alteraciones motoras (hemiparesia) de duración variable y cefaleas. En el 80 por ciento hay restitución a la normalidad (MHF1) y en el 20 por ciento ataxia y deficiencia neurológica (MHF2). El gen involucrado es el CACNA1A, en el cromosoma 19 p13. La frecuencia e intensidad de los ataques mejoran con acetozolamiday antidepresivos β menos bloqueantes (AU)

A comparison between multifocal and conventional VEP latency changes secondary to glaucomatous damage.

PURPOSE: To compare latencies of conventional visual evoked potentials (cVEPs) and multifocal VEPs (mfVEPs) in the same patients. Previous reports of prolonged cVEP latency suggest a vehicle for detecting abnormal ganglion cells and for monitoring neuroprotection. METHODS: Seventy-five glaucomatous eyes (47 patients), 75 eyes with suspected glaucoma (46 patients), and 41 control eyes (22 subjects) underwent achromatic automated perimetry and mfVEP and cVEP testing. The mfVEP stimulus was a scaled dart board with 60 sectors; each sector was a pattern-reversing checkerboard. The cVEP stimulus was a reversing checkerboard with checks of either 15 minutes or 60 minutes in width. RESULTS: Relatively few glaucomatous eyes had latencies that fell outside the range of control eyes, and there was little difference between the cVEP and mfVEP results. In the glaucoma group, 12.3% (15 minutes cVEP), 8% (60 minutes cVEP), and 17.3% (mfVEP) of the eyes and 5.3% (15 minutes cVEP), 6.7% (60 minutes cVEP), and 5.3% (mfVEP) of the suspect eyes exceeded the normal range. The glaucomatous eyes had, on average, relatively small increases in latency, compared with the control or suspect groups. Further, the latency of both the mfVEP and cVEP bore no obvious relationship to the mean deviation of the visual field. CONCLUSIONS: Contrary to previous reports, prolonged VEP delays were present in a minority of patients with glaucoma. Either a delayed VEP is not a good indicator of damaged, as opposed to dead, retinal ganglion cells, or there are relatively few patients who exhibit evidence of damaged ganglion cells.

The role of the multifocal visual evoked potential (mfVEP) latency in understanding optic nerve and retinal diseases.

PURPOSE: To examine the extent to which changes in the latency of the multifocal visual evoked potential (mfVEP) overlap in patients with glaucoma, recovered optic neuritis/multiple sclerosis (ON/MS), and retinal disease. METHODS: Monocular mfVEPs were obtained for both eyes of all subjects. Latencies and amplitudes of individual mfVEP responses were measured using custom software and expressed relative to a normative group (n = 100). Recordings were obtained from patients with ON/MS (n = 12), glaucoma (n = 50), and retinal disease (n = 15), as well as control subjects (n = 50). All subjects had 24-2 visual fields; patients with retinal disease had multifocal electroretinograms (mfERGs). The patients with retinal disease were examined by a neuro-ophthalmologist to rule out optic nerve disease and, in general, had relatively subtle or unremarkable fundus examinations but abnormal mfERG amplitudes. RESULTS: There was considerable overlap in the latencies for the patient groups for both monocular and interocular measures of mfVEP latency. This was particularly true for the patients with retinal disease and ON/MS, for whom the range of latencies was almost identical, as was the percentage of points in the field showing significant delays. CONCLUSION: The mfVEP delays seen in patients with retinal disease are similar in magnitude and prevalence to those seen in patients with a history of ON/MS. In general, this does not present a problem when using the mfVEP in the clinic. However, a retinal problem can be confused with ON/MS or, in fact, dismissed as functional, especially if the fundus appears normal.