SUMMARY1. Wte have used the method of current source density analysis to locate the generators of harmonic electroretinogram (ERG) responses to contrast-modulated pattern and uniform-field stimuli in the primate retina.2. Sinusoidal steady-state analysis was used, with a stimulus temporal frequency of 8 Hz. Fundamental and second-harmonic response components were measured for the uniform-field response. The second harmonic of the average of contrast-reversal pattern responses obtained at a series of spatial phases was also determined in the same experiments. In addition, retinal tissue resistance was measured. All of these measurements were obtained at a series of equally spaced depths in the retina.3. Retinal resistivity was not observed to vary systematically with depth. In addition, any plausible undetected inhomogeneities of resistivity with depth were found to slightly affect the relative magnitudes of estimated current sources and sinks, but to have little effect on their localization.4. In a given penetration, the phase lag of each harmonic component was relatively constant with depth in most cases; however the magnitude of this phase lag sometimes varied in different penetrations. To compare data from different penetrations, the constant phase lag for each harmonic was estimated, and the response data phase-shifted so as to bring all data into a standard (cosine) phase.5. The resulting current source density analyses were found to be quite consistent in overall form for different penetrations and in different animals. These data were averaged to obtain a final estimate of the depth profiles for generators of different ERG components.6. The uniform-field fundamental response was found to have a predominant source-sink pair in the distal half of the retina (receptor layer to outer plexiform layer). The pattern (second-harmonic) response generators had a quite different depth profile, consisting mainly of a source-sink pair in the proximal 20% of the retina (encompassing the nerve fibre layer to the middle of the inner plexiform layer).
Factor P was expressed in 50% of choroidal neovascular membranes of patients with AMD. The group with Factor P-positive membranes differed significantly from the Factor P-negative group in key clinical outcomes. Additional studies need to investigate the role of Factor P in the development of AMD for potential therapeutic intervention.
Correlations between clinical symptoms and complement factor C5 could be shown. The results strengthen the hypothesis of an involvement of the complement system in AMD.
Précis: Fixed high-energy selective laser trabeculoplasty (SLT) is associated with a greater reduction in intraocular pressure (IOP) compared with the standard titrated approach at up to 36 months postprocedure. Purpose: There is no consensus on ideal SLT procedural laser energy settings. This study aims to compare fixed high-energy SLT to the standard titrated-energy approach within the setting of a residency training program. Patients: Patients over the age of 18 years received SLT between 2011 and 2017, a total of 354 eyes. Patients with a prior history of SLT were excluded. Methods: Retrospective review of clinical data from 354 eyes that underwent SLT. Eyes that underwent SLT using fixed high energy (1.2 mJ/spot) were compared with those with the standard titrated approach starting at 0.8 mJ/spot and titrating to “champagne” bubbles. The entirety of the angle was treated using a Lumenis laser set to the SLT setting (532 nm). No repeat treatments were included. Main Outcome Measure: IOP and glaucoma medications. Results: In our residency training program, fixed high-energy SLT was associated with a reduction in IOP compared with a baseline of −4.65 (±4.49, n = 120), −3.79 (±4.49, n = 109), and −4.40 (±5.01, n =119) while standard titrated-energy was associated with IOP reduction of −2.07 (±5.06, n = 133), −2.67 (±5.28, n = 107), and −1.88 (±4.96, n = 115) at each respective postprocedural time point (12, 24, and 36 months). The fixed high-energy SLT group had significantly greater IOP reduction at 12 months and 36 months. The same comparison was performed for medication naïve individuals. For these individuals, fixed high-energy SLT resulted in IOP reductions of −6.88 (±3.72, n = 47), −6.01 (±3.80, n = 41), and −6.52 (±4.10, n = 46) while standard titrated-energy had IOP reductions of −3.82 (±4.51, n = 25), −1.85 (±4.88, n = 20), and −0.65 (±4.64, n = 27). For medication naïve individuals, fixed high-energy SLT resulted in a significantly greater reduction in IOP at each respective time point. Complication rates (IOP spike, iritis, and macular edema) were similar between the two groups. The study is limited by overall poor response to standard-energy treatments, whereas high-energy treatments showed similar efficacy to those in literature. Conclusion: This study demonstrates that fixed-energy SLT produces at least equivalent results compared with the standard-energy approach, without an increase in adverse outcomes. Particularly in the medication naïve subpopulation, fixed-energy SLT was associated with a significantly greater IOP reduction at each respective time point. The study is limited by overall poor response to standard-energy treatments, with our results showing decreased IOP reduction compared with those of previous studies. These poor outcomes of the standard SLT group may be responsible for our conclusion that fixed high-energy SLT results in a greater reduction in IOP. These results may be useful when considering optimal SLT procedural energy in future studies for validation.
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