Pattern Scanning Laser Photocoagulation Research Articles

Pattern scanning laser photocoagulation in the treatment of recurrent hyphema following gonioscopy-assisted transluminal trabeculotomy

Minimally invasive glaucoma surgeries (MIGS) are increasingly used in mild-to-moderate glaucoma cases. Among MIGS, gonioscopy-assisted transluminal trabeculotomy (GATT) is an alternative to conventional glaucoma surgeries. Although GATT is a safe procedure, its potential adverse effects should be considered. The most common complication is hyphema, which is usually transient and resolves spontaneously in the first postoperative week. However, cases of late postoperative hyphema have been reported. We report the case of a patient who developed persistent hyphema after undergoing GATT combined with cataract extraction that was successfully treated with PASCAL photocoagulation, with no further recurrences.

Lenticular burns following PASCAL photocoagulation.

Lenticular burns following PASCAL photocoagulation.

Novel low-cost approach to the treatment of ocular surface squamous neoplasia using pattern scanning laser photocoagulation.

To evaluate the safety and 12-month effect of treatment with pattern scanning laser photocoagulation for ocular surface squamous neoplasia in a low-resource setting with extremely limited access to an operating room. Adult patients with a clinical diagnosis of ocular surface squamous neoplasia underwent a complete ophthalmologic examination. After topical anesthesia and instillation of toluidine blue 1%, the lesion was treated using pattern scanning photocoagulation for a duration time that varied from 20 to 100 ms and power from 600 to 1,800 mW. Patients were examined on a weekly basis for the first month and underwent weekly retreatment of the remaining lesions, as necessary. Patients had a minimum follow-up of 12 months. Thirty-eight patients (38 eyes) were included. All patients had clinical ocular surface squamous neoplasia that was confirmed by impression cytology. The age of patients ranged from 40 to 83 years (average: 65.5 years) and 28 of them were males (74%). The patients were divided into two groups: group I (immunocompetent) and group II (immuno-suppressed). In group I, 23 patients (74%) presented complete response with lesion control after laser treatment alone. In group II, two of seven patients (28%) showed treatment response during the follow-up. The average number of treatments was 2.5 (one to six laser treatments). Procedures were well tolerated. Short-term results of the laser photocoagulation approach for the treatment of ocular surface squamous neoplasia conjunctival lesions were favorable, with a 74% success rate observed in immunocompetent patients. This novel strategy is a less resource-intensive alternative that could demonstrate its usefulness in settings with shortages in operating rooms and in recurrent cases. Studies with longer follow-ups and larger sample sizes are warranted to confirm our findings and evaluate the effectiveness of laser treatment in association with topical chemotherapy.

Novel treatment of papillomatous conjunctival lesions using pattern scanning laser photocoagulation: 1-Year results

PurposeTo evaluate the safety and 1-year effect of pattern scanning laser photocoagulation treatment for pedunculated papillomatous and sessile conjunctival lesions in a low-resource setting with extremely limited operating room access. MethodsAdult patients with clinical diagnosis of conjunctival papilloma underwent complete ophthalmologic exam including anterior segment photography. After topical anesthesia and toluidine blue 1% instillation, the lesion was treated by pattern scanning photocoagulation using a duration time that varied from 20 to 100 ms and power from 600 to 1800 mW, treating the entire lesion surface with a 2 mm margin. Patients were examined weekly for a month then monthly and underwent retreatment as necessary. ResultsSix patients and seven eyes that had clinically significant non-malignant pedunculated or sessile papillomatous lesions were treated. All lesions responded to treatment, with complete resolution after an average of 2.3 sessions. Procedures were well tolerated with only minor mild discomfort persisting up to two days post-treatment. Patients were followed for a mean follow-up time of 13 months with no recurrences reported. ConclusionShort-term results of the pattern scanning laser photocoagulation approach, with toluidine blue for papillomatous conjunctival lesions are favorable with a 100% success rate in this cohort. This rate is comparable to surgical excision. This novel strategy proved to be a less resource intensive alternative that not only could demonstrate its usefulness in settings with chronic operating room shortages, but also in recurrent cases. Longer follow-ups with a larger sample size and cost-analysis are necessary to confirm our findings.

Conjunctival cystectomy assisted by pattern scan laser photocoagulation

BackgroundTo introduce a new technique of laser-assisted conjunctival cystectomy using pattern scan laser (PASCAL) photocoagulation.Case presentationA 50-years-old Asian woman presented with a conjunctival cyst in the left eye. Slit-lamp examination revealed a 5 mm × 2 mm sized freely movable conjunctival cyst. After a 1 mm × 1 mm sized conjunctival opening was made using PASCAL photocoagulation, the cyst was extracted using a non-toothed forceps without rupture. Two weeks later, complete re-epithelialization of the conjunctiva was observed without any complications. No evidence of recurrence was noted over the 6-month follow-up period.ConclusionConjunctival cystectomy with the adjunctive use of PASCAL photocoagulation can be an effective and safe treatment method.

Changes in Macular Retinal Layers and Peripapillary Nerve Fiber Layer Thickness after 577-nm Pattern Scanning Laser in Patients with Diabetic Retinopathy.

PurposeThe aim of this study was to evaluate the changes in thickness of each macular retinal layer, the peripapillary retinal nerve fiber layer (RNFL), and central macular thickness (CMT) after 577-nm pattern scanning laser (PASCAL) photocoagulation in patients with diabetic retinopathy.MethodsThis retrospective study included 33 eyes with diabetic retinopathy that underwent 577-nm PASCAL photocoagulation. Each retinal layer thickness, peripapillary RNFL thickness, and CMT were measured by spectral-domain optical coherence tomography before 577-nm PASCAL photocoagulation, as well as at 1, 6, and 12 months after 577-nm PASCAL photocoagulation. Computerized intraretinal segmentation of optical coherence tomography was performed to identify the thickness of each retinal layer.ResultsThe average thickness of the RNFL, ganglion cell layer, inner plexiform layer, inner nuclear layer, inner retinal layer, and CMT at each follow-up increased significantly from baseline (p < 0.001), whereas that of the retinal pigment epithelium at each follow-up decreased significantly from baseline (p < 0.001). The average thickness of the peripapillary RNFL increased significantly at one month (p < 0.001). This thickness subsequently recovered to 7.48 µm, and there were no significant changes at six or 12 months compared to baseline (p > 0.05).ConclusionsEach macular retinal layer and CMT had a tendency to increase for one year after 577-nm PASCAL photocoagulation, whereas the average thickness of retinal pigment epithelium decreased at one-year follow-up compared to the baseline. Although an increase in peripapillary RNFL thickness was observed one month after 577-nm PASCAL photocoagulation, there were no significant changes at the one-year follow-up compared to the baseline.

Does Pattern Scan Laser (PASCAL) photocoagulation really induce less VEGF expression in murine retina than conventional laser treatment?

To investigate the differences in the mRNA and protein expression levels of vascular endothelial growth factor (VEGF) in murine retina between mice subjected to conventional laser (AG) and those subjected to Pattern Scan Laser (PASCAL) system. Male C57BL/6 mice were randomly assigned to one of three groups: Group 1 (G1) receiving retinal scatter laser photocoagulation using with AG photocoagulator (n=16), Group 2 (G2) receiving retinal scatter laser photocoagulation using with PASCAL (n=16) and Group 3 (G3) served as an untreated control group (n=6). Molecular and morphological analyses of VEGF were performed on days 1, 2 and 5 by ELISA, real-time PCR and immuno-histochemical analysis. In samples which underwent AG (G1), when compared with the control group (G3), VEGF mRNA level increased 2.4 folds on day 2, whereas it decreased on day 5 (p□0.001). In samples which underwent PASCAL (G2), on the other hand, VEGF mRNA level increased 1.8 folds on day 1 and 2.2 folds on day 5 when compared with the control group (G3). In samples which underwent AG (G1), when compared with the control group (G3), VEGF protein level increased significantly on day 2, whereas it decreased on day 5 (p□0.001). In group G2, the VEGF levels in the sensory retina significantly increased as compared to control groups at both 2 and 5days after laser photocoagulation using PASCAL laser (p=0.012, both time points). The peak expressions of VEGF protein in samples which underwent PASCAL and conventional laser were found on day 5 and day 2 respectively. In retinas of PASCAL-treated mice, VEGF immunoreactivity gradually increased during the 5-day follow-up. However, in argon laser group, the strongest VEGF immunoreactivity was detected on day 2, then started to decrease on day 5. In summary, the expression of VEGF protein and mRNA gradually increase during a 5-day follow-up period in PASCAL-treated mouse eyes, whereas in AG group they reach their peak levels on the second day of follow-up and started decreasing after then. These results may also explain why the PASCAL system is less effective in regressing neovascularization in the clinic.

The Effect of Pattern Scan Laser Photocoagulation on Peripapillary Retinal Nerve Fiber Layer Thickness and Optic Nerve Morphology in Diabetic Retinopathy

PurposeTo evaluate the effect of pattern scan laser (PASCAL) photocoagulation on peripapillary retinal nerve fiber layer (RNFL) thickness, central macular thickness (CMT), and optic nerve morphology in patients with diabetic retinopathy.MethodsSubjects included 35 eyes for the PASCAL group and 49 eyes for a control group. Peripapillary RNFL thickness, cup-disc area ratio and CMT were measured before PASCAL photocoagulation and at 2 and 6 months after PASCAL photocoagulation in the PASCAL or control groups.ResultsThe average RNFL thickness had increased by 0.84 µm two months after and decreased by 0.4 µm six months after PASCAL photocoagulation compared to baseline, but these changes were not significant (p = 0.83, 0.39). The cup-disc area ratio was unchanged after PASCAL photocoagulation. CMT increased by 18.11 µm (p = 0.048) at two months compared to baseline thickness, and partially recovered to 11.82 µm (p = 0.11) at six months in the PASCAL group.ConclusionsPASCAL photocoagulation may not cause significant change in the peripapillary RNFL thickness, CMT, and optic nerve morphology in patients with diabetic retinopathy.

Changes in peripapillary retinal nerve fiber layer thickness after pattern scanning laser photocoagulation in patients with diabetic retinopathy.

PurposeTo examine the effects of panretinal photocoagulation (PRP) using a pattern scanning laser (PASCAL) system on the retinal nerve fiber layer (RNFL) thickness in patients with diabetic retinopathy.MethodsThis retrospective study included 105 eyes with diabetic retinopathy, which consisted of three groups: the PASCAL group that underwent PRP with the PASCAL method (33 eyes), the conventional group that underwent conventional PRP treatment (34 eyes), and the control group that did not receive PRP (38 eyes). The peripapillary RNFL thickness was measured by optical coherence tomography before, six months, and one year after PRP to evaluate the changes in peripapillary RNFL.ResultsThe RNFL thickness in the PASCAL group did not show a significant difference after six months (average 3.7 times, p = 0.15) or one year after the PRP (average 3.7 times, p = 0.086), whereas that in the conventional group decreased significantly after six months (average 3.4 times, p < 0.001) and one year after PRP (average 3.4 times, p < 0.001).ConclusionsThe results of this study suggest that the PASCAL system may protect against RNFL loss by using less energy than conventional PRP.

Observation of clinical efficacy of pattern scan laser photocoagulation on diabetic retinopathy

Observation of clinical efficacy of pattern scan laser photocoagulation on diabetic retinopathy

Short-Duration Focal Pattern Grid Photocoagulation for Macular Edema Secondary to Branch Retinal Vein Occlusion

Purpose: To evaluate the safety, functional, and anatomical outcomes of short-duration pattern scanning laser (PASCAL) macular photocoagulation in the treatment of macular edema related to branch retinal vein occlusion (BRVO).Methods: Consecutive retrospective analysis of visual acuity (VA), optical coherence tomography (OCT), and adverse events from eyes treated with PASCAL macular photocoagulation for BRVO-related macular edema. Two-tailed paired t-tests were used to compare pre- and post-treatment VA and central retinal thickness (CRT).Results: A total of 35 eyes from 35 patients and 18 eyes from 18 patients met study criteria for VA and OCT analysis, respectively. All treatments were delivered with the same PASCAL photocoagulation unit. Mean laser settings were 133-µm spot size, 15-millisecond pulse duration, 250-mW power, and fluence of 29 J/cm2 with an average of 1.4 treatments and 335 shots per patient. Adjunct treatment with intravitreal anti-VEGF injections and pan-retinal photocoagulation was administered in 27 and 16 eyes, respectively. At an average follow-up of 12 months (range 3–43 months) post-treatment, no laser-related ocular complications were observed. Visual acuity was not significantly changed (p = 0.07), although the number of patients with vision better than 20/40 doubled following treatment. CRT was reduced by an average of 110 µm (p = 0.0009).Conclusion: Short-duration PASCAL macular photocoagulation appears to be a safe treatment option that results in significant anatomical improvement in macular edema related to BRVO.

SHORT-DURATION FOCAL PATTERN GRID MACULAR PHOTOCOAGULATION FOR DIABETIC MACULAR EDEMA

To evaluate the visual acuity (VA) and optical coherence tomography thickness results of short-duration pattern scanning laser macular photocoagulation in the treatment of clinically significant macular edema because of diabetes. Consecutive retrospective analysis of VA and optical coherence tomographic data from eyes treated in a modified Early Treatment Diabetic Retinopathy Study style using a short-duration pattern scanning laser. A total of 100 eyes from 70 patients met study criteria. All subjects were treated with the same PASCAL (pattern scanning laser) photocoagulation unit. Parameters varied according to media and pigmentation status, but typical settings were 100-μm spot size, 10-millisecond pulse duration, 225-mW power, and 29 J/cm fluence to give a pale but visible lesion. At 4 months posttreatment, there was an average improvement in VA of 0.060 logMAR (an improvement from 20/45 to 20/40, or approximately 3 Early Treatment Diabetic Retinopathy Study letters; P = 0.0007) and a reduction of central optical coherence tomographic thickness of 40 μm and 37 μm (spectral domain and time domain optical coherence tomography groups, respectively), both of which were statistically significant (P = 0.0049 and 0.012, respectively). Short-duration PASCAL macular photocoagulation has a biological treatment effect at 4 months for the treatment of clinically significant macular edema. While caution must be used when converting between different VA measurement methods and when using literature-based controls, the observed VA improvement seems equivalent to 3 Early Treatment Diabetic Retinopathy Study letters. These findings are similar to the recently published results from the diabetic retinopathy clinical research network cohort. PASCAL laser photocoagulation for clinically significant macular edema appears safe and effective in the short term and may have significant long-term advantages.

Pattern scan laser photocoagulation: safety and complications, experience after 1301 consecutive cases

Background/aimsThe pattern scan laser photocoagulator (PASCAL) is a novel laser device that uses 10–30 ms pulse duration for retina photocoagulation. The aim of this study was to analyse the safety...

Fundus autofluorescence and Fourier-domain optical coherence tomography imaging of 10 and 20 millisecond Pascal retinal photocoagulation treatment

Aim:To report the evolution of pattern scanning laser (Pascal) photocoagulation burns in the treatment of diabetic retinopathy, using Fourier-domain optical coherence tomography (FD-OCT) and fundus autofluorescence (AF), and to evaluate...