The change of macular thickness following single-session pattern scan laser panretinal photocoagulation for diabetic retinopathy

Long-term longitudinal retinal changes after conventional and pattern scan laser panretinal photocoagulation in diabetic retinopathy

PURPOSE

Comparison the effect of conventional and pattern scan laser (PASCAL) panretinal photocoagulation (PRP) on macula and optic disk in diabetic retinopathy (DR).

METHODS

This retrospective study included 57 patients. In the conventional laser group, PRP was completed using the LightMed LightLas 532 laser device in accordance with the ETDRS protocol. In the pattern laser group, it was completed in a single session using PASCAL device with 20 ms pulse duration and multispot pattern. Central macular thickness (CMT) and retinal nerve fiber layer (RNFL) thickness were evaluated before laser treatment and at 1, 6 and 12 months after treatment.

RESULTS

There were 30 eyes in the conventional laser group and 27 eyes in the PASCAL group. There was no significant difference between the groups in terms of age (p = 0.560), sex (p = 0.866), duration (p = 0.498) and stage (p = 0.503) of diabetes, visual acuity (p = 0.104) and intraocular pressure (p = 0.963).In both groups, CMT increased significantly (p ˂0.001), while RNFL thickness decreased significantly (p ˂0.001) at 12 months. While CMT and mean RNFL thickness increased in the first month in both groups, it decreased progressively until the 12th month.

CONCLUSION

Conventional and pattern laser systems used in the treatment of DR................ cause an increase in CMT and thinning of RNFL thickness in the long term. This change is more in the conventional laser group compared to the pattern laser.

Optical Coherence Tomography Angiography Assessment of Macular Choriocapillaris and Choroid Following Panretinal Photocoagulation in a Diverse Population With Advanced Diabetic Retinopathy

PURPOSE

The aim of this study was to evaluate choroidal and retinal microvasculature with optical coherence tomography angiography (OCTA) after panretinal photocoagulation (PRP) for diabetic retinopathy in a primarily Hispanic and Asian population.

DESIGN

Retrospective study.

METHODS

Eyes were examined by OCTA in the macula (3 × 3 mm) just before PRP treatment and 1 to 3 months afterwards. Choroidal thickness (CT) and central retinal thickness (CRT) were measured. Choroidal flow signal voids (CFSV) and choriocapillaris flow signal voids (CCFSV) were acquired. Retinal microvasculature parameters, including superficial and deep vessel density, superficial and deeper perfusion density, foveal avascular zone area, perimeter and circularity, were calculated. Ocular examinations and demographic information were analyzed.

RESULTS

CT at a location 1000 μm temporal to the fovea increased significantly after PRP (from 278.64 μm to 313.44 μm, P = 0.026). CCFSV increased slightly from (46.72 ± 8.52)% to (47.07 ± 10.77)%, but the difference was not statistically significant (P = 0.782). A similar finding was observed in CFSV (increase from 35.81% to 36.64%, P = 0.165). The change in all retinal microvasculature parameters was also not significant. Best-corrected visual acuity (BCVA) decreased from 0.218 ± 0.153 to 0.262 ± 0.147 (P = 0.034). Increased CRT (from 245.41 ± 33.18 μm to 251.14 ± 38.97 μm, P = 0.007) was observed. The change in CRT positively correlated with pre-PRP CRT (r = 0.434, P = 0.019) and BCVA reduction (r = 0.418, P = 0.024). Neither BCVA reduction nor CRT increase correlated with OCTA metrics.

CONCLUSIONS

OCTA demonstrates redistribution of choroidal circulation from the periphery to the macula after PRP, with increased macular CT and stable choroidal blood flow density. Eyes with greater macular thickness are more likely to experience an increase in CRT.

Central retinal thickness following panretinal photocoagulation using a multispot semi-automated pattern-scanning laser to treat ischaemic diabetic retinopathy: Treatment in one session compared with four monthly sessions

PURPOSE

To compare central retinal thickness (CRT) after panretinal photocoagulation (PRP) with a multispot semi-automated PAttern-SCAnning Laser (PASCAL) in one session (SS-PRP) versus four monthly sessions (MS-PRP) in diabetic retinopathy.

METHODS

Multicentre, prospective, randomized, single-blinded, controlled trial evaluating the noninferiority of SS-PRP versus MS-PRP for CRT measured with macular spectral-domain optical coherence tomography (SD-OCT), with a 9-month follow-up in patients presenting severe nonproliferative diabetic retinopathy (DR) or mild proliferative DR without macular oedema (ME) at baseline.

RESULTS

Ninety-seven eyes of 97 participants with a mean age of 57.0 ± 14.2 years were included. The mean change of CRT from baseline to 9 months was not statistically different in SS-PRP or in MS-PRP: +16.9 ± 28.3 μm versus +24.7 ± 31.8 μm, respectively (p = 0.224). The variation in mean best-corrected visual acuity (BCVA) from baseline to 9 months was similar in both groups: -1.1 ± 6.5 letters versus -0.6 ± 6.2 letters (p = 0.684). The number of patients with stabilization of DR was not statistically different between the two groups. No severe complication was recorded in either group.

CONCLUSION

This study showed the noninferiority of PRP performed in one session versus four monthly sessions with a PASCAL concerning central retinal thickness for treating mild proliferative or severe nonproliferative DR without ME at baseline.

Single session of pattern scanning laser versus multiple sessions of conventional laser for panretinal photocoagulation in diabetic retinopathy: Efficacy, safety and painfulness

Purpose

To evaluate the clinical efficiency, safety and painfulness of retinal laser photocoagulation employing a pattern scanning laser system Pascal given in a single-session versus conventional laser multiple-session treatment of the same patient with diabetic retinopathy during 12-month follow-up.

Methods

The cohort included 60 eyes in 30 patients treated at the Ophthalmology Clinic, Faculty Hospital Ostrava, from 2008 to 2013. Panretinal laser coagulation was performed on one eye using the multispot panretinal photocoagulation given in a single-session system Pascal (OptiMedica, Santa Clara, California). On the other eye laser treatment was carried out by the classic conventional multiple-session method.

Results

The performance of Pascal panretinal laser coagulation was evaluated as significantly less painful (visual scale of pain was 3.28 ± 1.9) than the performance of conventional photocoagulation (visual scale of pain was 3.93 ± 1.88) with similar efficiency. Distribution of progression of diabetic retinopathy in individual patients was very similar in both groups under comparison, and was strictly paired in 24 of the 30 patients at the end of 1-year follow-up.

Conclusion

Laser photocoagulation of the retina with the use of short impulse durations and patterns in patients with diabetic retinopathy given in one session possesses similar efficiency to that of conventional retinal photocoagulation in multiple sessions. The single session treatment is also better tolerated by patients and in addition to this, it shortens the performance of the whole therapy, which potentially saves considerable funds of all subjects participating in the process of treatment.

Trial registration

ClinicalTrials.gov NCT03672656.

Effect of 0.05% Difluprednate Ophthalmic Emulsion on Proinflammatory Cytokine Levels After Retinal Laser Photocoagulation in Rabbits

PURPOSE

We aimed to evaluate the effect of the topical application of a strong corticosteroid, difluprednate, on the levels of inflammatory and angiogenic cytokine in the vitreous and aqueous humor after laser photocoagulation.

METHODS

Pigmented rabbits were treated with retinal laser photocoagulation and divided into 4 groups, namely control (no additional treatment), topical application of difluprednate 0.05%, betamethasone sodium phosphate 0.1%, and sub-Tenon injection of triamcinolone acetonide (STTA). Samples of vitreous and aqueous humor were collected on posttreatment days 0, 1, 7, and 14. The levels of intraocular vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), intercellular adhesion molecule-1 (ICAM-1), and monocyte chemotactic protein-1 (MCP-1) were measured using an immunoassay. Intraocular pressure (IOP) was monitored in each group.

RESULTS

VEGF, IL-6, ICAM-1, and MCP-1 were significantly elevated on day 1 and were reduced in both the vitreous and aqueous humor following topical application of difluprednate and STTA. Topical betamethasone reduced their levels in the aqueous humor but not in the vitreous. A significant increase of IOP induced by difluprednate returned to control levels after withdrawal of administration.

CONCLUSION

Although the elevation of IOP was an expected, manageable side effect, topical application of difluprednate was more effective than STTA and betamethasone for reducing inflammatory cytokine levels after laser treatment.

Effect of Topical Nepafenac on Central Foveal Thickness following Panretinal Photocoagulation in Diabetic Patients

Purpose

To evaluate effectiveness of topical nepafenac in reducing macular edema following panretinal photocoagulation (PRP).

Design

Prospective randomized double-blinded controlled study.

Methods

Sixty eyes of 60 patients having proliferative or severe nonproliferative diabetic retinopathy had PRP. Patients were then divided into two groups: nepafenac group (30 eyes) receiving 1% topical nepafenac eye drops for 6 months and control group (30 eyes) receiving carboxymethylcellulose eye drops for 6 months. Best-corrected visual acuity (BCVA) and macular optical coherence tomography were followed up at 1, 2, 4, and 6 months after PRP.

Results

BCVA was significantly better in nepafenac group than in control group at all follow-ups (P < 0.01). At 6 months post-PRP, logMAR BCVA was 0.11 ± 0.04 (equivalent to 20/26 Snellen acuity) in the nepafenac group and 0.18 ± 0.08 (equivalent to 20/30 Snellen acuity) in the control group (P < 0.01). Central foveal thickness (CFT) increased in both groups from the first month after PRP. Increase in CFT was higher in control group than in nepafenac group throughout follow-up, but the difference became statistically significant only after 4 months. No significant ocular adverse events were reported with topical nepafenac.

Conclusion

Topical nepafenac can minimize macular edema and stabilize visual acuity following PRP for diabetic patients.

Comparison of Efficacy and Side Effects of Multispot Lasers and Conventional Lasers for Diabetic Retinopathy Treatment

Panretinal photocoagulation (PRP) is a standard treatment for proliferative diabetic retinopathy. Conventional laser (CL) therapy is performed in one or more sessions in single spot mode. Visual disabilities have been reported after treatment with CL, including central vision loss due to macular edema and peripheral visual field loss resulting from extensive inner retinal scarring. Multispot laser (MSL) photocoagulation has recently been introduced to clinical practice. Studies comparing PRP conducted with MSL and CL have reported that MSLs resulted in less retinal tissue damage and pain, and greater patient comfort compared to CL. The aim of this review was to compare the efficacy and side effects of MSLs and CLs for diabetic retinopathy treatment.

Retinal fibrosis in diabetic retinopathy

In response to injury, reparative processes are triggered to restore the damaged tissue; however, such processes are not always successful in rebuilding the original state. The formation of fibrous connective tissue is known as fibrosis, a hallmark of the reparative process. For fibrosis to be successful, delicately balanced cellular events involving cell proliferation, cell migration, and extracellular matrix (ECM) remodeling must occur in a highly orchestrated manner. While successful repair may result in a fibrous scar, this often restores structural stability and functionality to the injured tissue. However, depending on the functionality of the injured tissue, a fibrotic scar can have a devastating effect. For example, in the retina, fibrotic scarring may compromise vision and ultimately lead to blindness. In this review, we discuss some of the retinal fibrotic complications and highlight mechanisms underlying the development of retinal fibrosis in diabetic retinopathy.

Changes in Central Macular Thickness following Single Session Multispot Panretinal Photocoagulation

Purpose. To determine changes in central subfield (CSF) macular thickness and best corrected visual acuity (BCVA) following single session, multispot panretinal photocoagulation (PRP). Methods. Forty eyes of 33 patients with newly diagnosed proliferative diabetic retinopathy were treated with single session, 20-millisecond, multispot PRP. Changes in central macular thickness and BCVA at 4- and 12-week follow-up were compared to baseline measurements. Results. Each eye received a mean (SD) of 2,750 (686.7) laser spots. At 4-week follow-up, there was a statistically significant 24.0 μm increase in mean CSF thickness (P = 0.001), with a 17.4 μm increase from baseline at 12-week follow-up (P = 0.002). Mean logMAR BCVA increased by 0.05 logMAR units (P = 0.03) at 4-week follow-up. At 12-week follow-up, BCVA had almost returned to normal with only an increase of 0.02 logMAR units compared to baseline (P = 0.39). Macular edema occurred in 2 eyes (5%) at 12-week follow-up. Conclusions. Macular thickening occurs following single session, 20-millisecond, multispot PRP, with a corresponding, mild change in BCVA. However, the incidence of macular edema appears to be low in these patients. Single session, 20-millisecond, multispot PRP appears to be a safe treatment for patients with proliferative diabetic retinopathy.