The Impact of Pulse Duration and Burn Grade on Size of Retinal Photocoagulation Lesion

Palanker, Daniel; Lavinsky, Daniel; Blumenkranz, Mark S.; Marcellino, George

doi:10.1097/iae.0b013e3182115679

Cited by 38 publications

(51 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Palanker et al [23] pointed out that while the exact mechanisms of laser treatment are unknown, the following factors are important: ablation of a fraction of highly metabolically active photoreceptor cells to decrease retinal oxygen consumption, creation of photoreceptor-free glial “windows” to improve oxygenation and metabolic transport, and thermal stimulation of adjacent retinal pigment epithelium cells. The clinical effect of these mechanisms is likely to be proportional to the total treated area.…”

Section: Discussionmentioning

confidence: 99%

Comparison of 577-nm Multispot and Standard Single-Spot Photocoagulation for Diabetic Retinopathy

et al. 2018

View full text Add to dashboard Cite

Objective: To compare two different laser strategies of panretinal photocoagulation for diabetic retinopathy. Methods: Single-center, randomized study including 41 eyes treated with 577-nm multispot laser with a 20-ms pulse duration (group 1) or a 532-nm single-spot laser with a 100-ms pulse duration (group 2). The outcomes included best-corrected visual acuity (BCVA) and imaging changes at baseline, 6 and 12 months, laser parameters, and results of subjective pain analysis. Results: At 12 months, the treatments did not differ significantly in BCVA, central retinal thicknesses (CRTs), improved macular edema, vitreomacular interface changes, patient-reported pain scores, or angiographic responses. Group 1 had significantly fewer treatment sessions but used more laser spots (p < 0.001). Conclusion: The multispot laser required fewer applications with more spots delivered to compensate for lower fluency, showing similar patient tolerance to single-spot laser. Both groups maintained the initial visual acuities and CRTs; about 50% of cases had vitreomacular interface changes and improved macular edema, with similar angiographic improvements after 12 months.

show abstract

Section: Discussionmentioning

confidence: 99%

Comparison of 577-nm Multispot and Standard Single-Spot Photocoagulation for Diabetic Retinopathy

et al. 2018

View full text Add to dashboard Cite

show abstract

“…This is within the size range of laser lesions resulting from moderate burn grade during photocoagulation treatment. [25,26] It is probably possible to detect smaller lesions in these search areas, but to do so would require larger grids, more trials, and more time. The 1.1° scotoma detection in the 10° search area required an 11 x 11 grid (experiment 1), 145 trials, and took approximately 5 -7 minutes to complete.…”

Section: Discussionmentioning

confidence: 99%

“…Based on lesion sizes from laser therapy studies, [25,26] the overall goal of the study was to determine if it was possible to detect a 1.1° scotoma in the central 10° or 20° of the visual field using the feature search paradigm. The theoretical capability of a feature search test in detecting a scotoma is determined by the search area, search grid size, and search item size.…”

Section: Stimulus Description Visual Search Task and General Proceduresmentioning

confidence: 99%

“…Laser lesions from photocoagulation therapy vary in size and severity although moderate lesions generally range in size from approximately 300-600 um in greatest diameter, which corresponds to approximately 1-2 degrees of visual angle. [25,26] An initial experiment using experienced observers was completed (also some pilot data was collected prior to the experiment) to determine some of the relationships between search area, grid size, search stimulus size and density, and visual feature types and to establish parameters that were used in a second experiment. The second experiment used naïve observers under test conditions that more closely reflected a real-life laser injury scenario.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Visual Search in the Detection of Retinal Injury: A Feasibility Study

Kuyk¹,

Liu²,

Belleau³

2013

View full text Add to dashboard Cite

“…Conventional judgement of photocoagulation lesions evaluates retinal whitening in three or four categories, [29][30][31] which is observer-dependent and requires evaluation by several investigators in clinical trials. 32 The judgement depends on the latency from application to evaluation as well.…”

Section: Discussionmentioning

confidence: 99%

Temperature-Controlled Retinal Photocoagulation Reliably Generates Uniform Subvisible, Mild, or Moderate Lesions

Koinzer

Baade

Schlott

et al. 2015

Trans. Vis. Sci. Tech.

View full text Add to dashboard Cite

Purpose: Conventional retinal photocoagulation produces irregular lesions and does not allow reliable control of ophthalmoscopically invisible lesions. We applied automatically controlled retinal photocoagulation, which allows to apply uniform lesions without titration, and aimed at five different predictable lesion intensities in a study on rabbit eyes.Methods: A conventional 532-nm photocoagulation laser was used in combination with a pulsed probe laser. They facilitated real-time fundus temperature measurements and automatic exposure time control for different predefined time/ temperature dependent characteristics (TTC). We applied 225 control lesions (exposure time 200 ms) and 794 TTC lesions (5 intensities, exposure times 7-800 ms) in six rabbit eyes with variable laser power (20-66.4 mW). Starting after 2 hours, we examined fundus color and optical coherence tomographic (OCT) images over 3 months and classified lesion morphologies according to a seven-stage OCT classifier.Results: Visibility rates in funduscopy (OCT) after 2 hours were 17% (68%) for TTC intensity group 1, 38% (90%) for TTC group 2 and greater than 94% (.98%) for all consecutive groups. TTC groups 1 through 4 correlated to increasing morphological lesion intensities and increasing median funduscopic and OCT diameters. Group 5 lesions were as large as, but more intense than group 4 lesions.Conclusions: Automatic, temperature controlled photocoagulation allows to apply predictable subvisible, mild, or moderate lesions without manual power titration.Translational Relevance: The technique will facilitate standardized, automatically controlled low and early treatment of diabetic retinopathy study (ETDRS) intensity photocoagulation independently of the treating physician, the treated eye and lesion location.

show abstract

The Impact of Pulse Duration and Burn Grade on Size of Retinal Photocoagulation Lesion

Abstract: A simple formula is derived for calculation of the required spot spacing in the laser pattern for panretinal photocoagulation with various laser parameters to maintain the same total coagulated area.

Cited by 38 publications

References 23 publications

Comparison of 577-nm Multispot and Standard Single-Spot Photocoagulation for Diabetic Retinopathy

Comparison of 577-nm Multispot and Standard Single-Spot Photocoagulation for Diabetic Retinopathy

Visual Search in the Detection of Retinal Injury: A Feasibility Study

Temperature-Controlled Retinal Photocoagulation Reliably Generates Uniform Subvisible, Mild, or Moderate Lesions

Contact Info

Product

Resources

About