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

Effect of Repeated Intravitreal Injections in Glaucoma Spectrum Diseases

Purpose

To evaluate whether repeated intravitreal injections (IVI) with an anti-vascular endothelial growth factor (anti-VEGF) agent are associated with glaucomatous progression in eyes with glaucoma spectrum diseases (GSD).

Methods

Single-center, retrospective, longitudinal study of patients with bilateral and similar GSD who: (1) received ≥8 IVI in only one eye during the study period; (2) had ≥2 retinal nerve fiber layer thickness (RNFL) measurements obtained by spectral-domain optical coherence tomography (SD-OCT) at least 12 months apart. The primary outcome was the absolute RNFL thickness change, comparing injected and fellow uninjected eyes. Linear mixed effects models were constructed, including a multivariable model.

Results

Sixty-eight eyes from 34 patients were included, 34 injected and 34 fellow uninjected eyes. Average baseline age was 67.68±21.77 years with a follow-up of 3.66±1.89 years and 25.12±14.49 IVI. RNFL thickness decreased significantly from 80.92±15.78 to 77.20±17.35 μm (p<0.001; -1.18±1.93 μm/year) in injected eyes and from 79.95±17.91 to 76.61±17.97 μm (p<0.001; -1.07±0.98 μm/year) in uninjected eyes. In a multivariable linear mixed model of injected eyes, only higher baseline RNFL thickness (p < 0.001) significantly predicted higher absolute RNFL thickness loss. Neither absolute RNFL thickness variation (p=0.716) nor RNFL rate (p=0.779) was significantly different between paired injected and uninjected eyes. Absolute IOP variation was not significantly different between groups (16.62±4.77 to 15.09±4.34 mmHg in injected eyes and 17.68±5.01 to 14.50±3.39 mmHg in fellow uninjected eyes; p=0.248). The proportion of eyes receiving glaucoma medical treatment increased significantly in both groups (55.9% to 76.5% in injected eyes; p=0.039; 58.8% to 76.5% in uninjected eyes; p = 0.031). The number of glaucoma medications also increased significantly in both groups (1.03±1.11 to 1.59±1.18 glaucoma medications in injected eyes; p=0.003; 1.09±1.11 to 1.56±1.19 glaucoma medications in uninjected eyes; p=0.003).

Conclusion

Repeated IVI do not seem to accelerate glaucomatous progression. Future studies with a longer follow-up are needed.

Long-term effect of panretinal photocoagulation on optic nerve head parameters in diabetic retinopathy using Heidelberg retinal tomography III

PURPOSE

The aim of this study was to evaluate the effect of panretinal photocoagulation (PRP) in diabetic retinopathy patients using Heidelberg retinal tomography III (HRT).

SUBJECTS AND METHODS

A total of 90 eyes of 90 consecutive newly diagnosed patients with diabetic retinopathy (nonproliferative diabetic retinopathy, NPDR, Group I and proliferative, PDR, Group II) were recruited for the study. The eyes with PDR were subjected to PRP. The effect of PRP was measured on optic nerve head (ONH) parameters using HRT.

RESULTS

Follow-up up to 4 years in both groups indicated that in Group II proliferative diabetic retinopathy (PDR) participants undergoing PRP, the ONH parameters showed a significant difference in cup area (P = 0.023), cup volume (P = 0.001), mean cup depth (P = 0.015), maximum cup depth (P < 0.001), mean retinal nerve fiber layer (RNFL) thickness (P < 0.001) at 1 year of follow-up, and remained significant in all at 4 years of follow-up, whereas there was no significant difference in any of the optic disc parameters in the participants of Group I belonging to NPDR group as compared to PDR group after 4 years.

CONCLUSION

PRP affected the ONH morphology in the PDR group and the effect of this change should be interpreted with caution. This may require setting a new baseline for RNFL measurements using the HRT when documenting RNFL loss or glaucoma progression in patients who have undergone PRP.

Long-term effects of pattern scan laser pan-retinal photocoagulation on diabetic retinopathy in Chinese patients: a retrospective study

AIM

To evaluate the long-term effects of pattern scan laser (PASCAL) pan-retinal photocoagulation (PRP) on diabetic retinopathy (DR) in Chinese patients.

METHODS

In this retrospective study, we evaluated clinical data of 29 patients (53 eyes) with severe non-proliferative DR (SNPDR) or proliferative DR (PDR) who received PRP and follow-up at our hospital from 2008 to 2013. Sixteen patients (29 eyes) received PASCAL PRP and 13 patients (24 eyes) received 100-ms conventional laser PRP.

RESULTS

After long-term follow-up (mean, min-max days: 719.8, 290-1666 for PASCAL PRP vs 743.5, 240-1348 for conventional PRP, P=0.569), patients receiving PASCAL PRP required fewer photocoagulation sessions than the conventional PRP group (2.6±1.0 vs 3.9±0.9, P<0.01). Best corrected visual acuity (BCVA) was reduced slightly in PASCAL PRP group while reduced significantly in conventional PRP group. At last visit, 24 eyes in the PASCAL group (88.9%) and 21 eyes in the conventional group (91.7%) were improved or stable. Two eyes in PASCAL PRP group (7.4%) and 3 eyes in the conventional PRP group (12.5%) developed vitreous hemorrhage or vitreous fibrovascular proliferation.

CONCLUSION

PASCAL PRP is as effective and may be more conducive to maintaining visual acuity with less treatment sessions for DR treatment compared to conventional laser PRP.

A meta-analysis to study the effect of pan retinal photocoagulation on retinal nerve fiber layer thickness in diabetic retinopathy patients

Background. Diabetic retinopathy is a microvascular disease, it is associated with changes in peripapillary retinal nerve fiber layer thickness, these changes being more pronounced in PDR (Proliferative diabetic retinopathy) patients undergoing laser photocoagulation. Objective. To assess changes in peripapillary retinal nerve fiber layer thickness in proliferative diabetic retinopathy patients using optical coherence tomogram (OCT). Methods. The database search was conducted in June 2018 and continued until October 2018. The search engines used included Pubmed, Medline, OVID and Google Scholar. A meta-analysis of weighted mean difference and standard deviation was conducted. Results. A total of 10 studies containing 377 eyes of PDR patients were selected. The analysis of the included studies revealed no significant effect of PRP on average retinal nerve fiber layer thickness (0.249, 95% CI: -0.985 to 1.483) using OCT. Conclusion. Hence, to conclude, our meta-analysis revealed that there was no significant effect of PRP on RNFL thickness and the impact of PRP could vary. Measurement of peripapillary RNFL thickness may yield erroneous and unpredictable results in this subgroup of patients, further confounding the evaluation of nerve fiber layer damage and its progression.

Long term effect of panretinal photocoagulation on retinal nerve fiber layer parameters in patients with proliferative diabetic retinopathy

PURPOSE:

This study aimed to evaluate the long-term effect of panretinal photocoagulation (PRP) on the retinal nerve fiber layer (RNFL) in patients with proliferative diabetic retinopathy (PDR).

METHODS:

This was a prospective longitudinal cohort study examining 42 eyes of 42 patients with PDR undergoing PRP. Peripapillary RNFL thickness (RNFLT) was measured using spectral-domain optical coherence tomography at baseline, 1 year, and 3 years following PRP.

RESULTS:

The mean “average RNFLT” was 89.88 ± 14.26 μm at baseline, 85.75 ± 11.36 μm at 1-year follow-up, and 83.33 ± 11.96 μm at 3-year follow-up. There was a statistically significant difference in the average RNFL thickness at baseline and 1 year and 3 years after PRP. At 1-year follow-up, superior, inferior, and nasal RNFL measurements reduced significantly from baseline (P < 0.01). The reduction in RNFL remained statistically significant for superior and inferior quadrants 3 years after PRP.

CONCLUSION:

PRP causes a reduction in RNFL thickness until 3 years after the procedure. Caution should be exercised while interpreting peripapillary RNFL thickness scans in patients who have undergone PRP for diabetic retinopathy.

The Effect of Panretinal Photocoagulation (PRP) versus Intravitreal Bevacizumab (IVB) Plus PRP on Peripapillary Retinal Nerve Fiber Layer (RNFL) Thickness Analyzed by Optical Coherence Tomography in Patients with Proliferative Diabetic Retinopathy

Purpose:

The current study aimed to evaluate changes in peripapillary retinal nerve fiber layer (RNFL) thickness in diabetic patients with bilateral proliferative diabetic retinopathy (PDR) after receiving panretinal photocoagulation (PRP) or intravitreal bevacizumab (IVB) with PRP.

Methods:

Ocular examination and peripapillary optical coherent tomography (OCT) were performed for each patient at baseline, 1, 3, 6, and 10 months after treatment. Both eyes of each patient were randomized into either PRP or PRP + IVB group.

Results:

Sixty-four eyes (32 patients) were enrolled in this randomized clinical trial. In the PRP group, global RNFL thickness initially increased and reached statistical significance in the third month (from 105.9 ± 21.4μm at baseline to 119 ± 41.6μm at 3 months, P = 0.03). Subsequent decline was observed with no significant difference from baseline at 10 months (106 ± 19.3μm, P = 0.914). There were no statistically significant changes in the PRP + IVB group (from 101.7 ± 22.2μm at baseline to 109.3 ± 26.9μm at 3 months, P = 0.996 and 101.9 ± 16.5μm at 10 months, P = 0.999). In the latter group, slight increase in RNFL thickness was observed in the first month (107.7 ± 21.1μm). RNFL thickness was similar to baseline in the two groups at month 10, with the exception of significant increase in superior-temporal sector in the PRP group (145.3 ± 13.4μm vs. 127.2 ± 17.3μm, P = 0.045).

Conclusion:

Compared to eyes treated with PRP, eyes treated with adjunctive IVB showed less significant post-treatment changes in RNFL thickness.

Quantitative analysis of neural tissues around the optic disc after panretinal photocoagulation in patients with diabetic retinopathy

In this retrospective cross-sectional study, we quantitatively analyzed the tomographic features in the neural tissues around the optic disc in patients with diabetic retinopathy with and without panretinal photocoagulation. We analyzed 206 eyes, comprising 33 normal eyes in subjects without diabetes (group I), 30 eyes without diabetic retinopathy (group II), 66 eyes with non-proliferative diabetic retinopathy (group III), 45 eyes with panretinal photocoagulation (group IV), and 32 eyes with normal tension glaucoma (group V). Sequential images acquired using swept-source optical coherence tomography in three-dimensional mode were used to measure peripapillary retinal nerve fiber layer thickness, neuro-retinal rim thickness, anterior lamina cribrosa depth, prelaminar thickness, and thickness of the lamina cribrosa. The peripapillary retinal nerve fiber layer thickness and lamina cribrosa thickness were significantly thinner in group IV than in group III (p = 0.019 and p < 0.001). However, there was no significant difference in rim thickness, anterior lamina cribrosa depth, or prelaminar thickness between groups III and IV (p = 0.307, p = 0.877, and p = 0.212). Multivariate analysis revealed that time since panretinal photocoagulation and thickness of the lamina cribrosa had a significant effect on peripapillary retinal nerve fiber layer thickness (p < 0.001 and p = 0.014). In group IV, there was a negative correlation between time elapsed since panretinal photocoagulation and peripapillary retinal nerve fiber layer thickness, rim thickness, and thickness of the lamina cribrosa (r = -0.765, r = -0.490, and r = -0.419), but no correlation with prelaminar thickness or anterior lamina cribrosa depth (r = 0.104 and r = -0.171). Panretinal photocoagulation may be related to thinning of the peripapillary retinal nerve fiber layer, rim thickness, and lamina cribrosa, but not prelaminar thickness or anterior lamina cribrosa depth. These features are different from the peripapillary features of eyes with typical normal tension glaucoma.

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

Purpose

The 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.

Methods

This 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.

Results

The 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).

Conclusions

Each 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.

Peripapillary RNFL Thickness Changes after Panretinal Photocoagulation

PURPOSE

To evaluate changes in peripapillary retinal nerve fiber layer (RNFL) thickness as determined by spectral domain optical coherence tomography (SD-OCT) after panretinal photocoagulation (PRP) for proliferative diabetic retinopathy (PDR).

METHODS

Forty-two eyes of 42 diabetic patients who were scheduled for PRP were enrolled in this interventional case series. Peripapillary RNFL thickness was measured using SD-OCT (OCT 1000; Topcon Co., Tokyo, Japan) at baseline and 1, 3, and 6 months after PRP.

RESULTS

Mean global RNFL thickness was increased significantly by 3 μm (p = 0.04) 1 month after PRP and was then decreased marginally significantly by 2.4 μm at 6 months (p = 0.054) as compared to baseline values. After 1 month, RNFL thickness was increased in all quadrants, but only changes in the temporal quadrant were significant (p = 0.009). At 6 months, progressive RNFL thinning occurred in all quadrants; however, only changes in the superior quadrant were significant (p = 0.041). Visual acuity was improved by an average of 0.02 logMAR after 6 months, but this change was not statistically significant.

CONCLUSIONS

Shortly after PRP, RNFL thickness (as determined by SD-OCT) increases, but a decrease in RNFL thickness occurs at 6 months post-PRP. RNFL thickness changes based on OCT should be interpreted with caution in diabetic eyes undergoing PRP.

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 MORPHOMETRY CHANGES MEASURED WITH SPECTRAL DOMAIN-OPTICAL COHERENCE TOMOGRAPHY AFTER PAN-RETINAL PHOTOCOAGULATION IN PATIENTS WITH PROLIFERATIVE DIABETIC RETINOPATHY

PURPOSE

To identify the effects of pan-retinal laser treatment on the integrity of neurosensory retinal layers.

METHODS

Patients were examined with fluorescence angiography after a standardized examination for diabetic retinopathy and a peripapillary ring scan with spectral domain optical coherence tomography. A single-session pan-retinal photocoagulation was performed using the PASCAL pattern scanning argon laser applying a minimum of 1,500 spots. Optical coherence tomography was evaluated more than 6 months.

RESULTS

Eighteen eyes of 12 consecutive patients with new onset, treatment-naive proliferative diabetic retinopathy secondary to diabetes Type 2 were treated and retinal optical coherence tomography morphology evaluated. Retinal nerve fiber layer thickness increased statistically significantly from baseline to week 1, when it reached its peak. The combined thickness of the outer plexiform and the inner nuclear layers and the combined thickness of the inner plexiform and the ganglion cell layers showed no relevant changes. The combined thickness of the retinal pigment epithelium and the photoreceptor cell layers decreased at month 1 followed by a steady increase in thickness, which remained below baseline values over time.

CONCLUSION

Pan-retinal photocoagulation in proliferative diabetic retinopathy leads to a slowly reversible, marked biological response with statistically significant morphometric changes detected by spectral domain optical coherence tomography. Swelling of the retinal nerve fiber and outer nuclear layers induce an increase in peripapillary total retinal thickness. Simultaneously, the photoreceptor and retinal pigment epithelium layers decrease in thickness. These changes indicate diffuse retinal inflammation after pan-retinal laser therapy.

Effects of timing of vitrectomy performed for open-globe injury patients on the thickness of retinal nerve fiber layer

Objective:

To study the effects of timing of vitrectomy performed for open-globe injury patients on the thickness of retinal nerve fiber layer (RNFL).

Methods:

A total of 120 patients with traumatic optic neuropathy (TON) were selected and divided into a treatment group and a control group by random draw (n=60). Vitrectomy was performed within one week upon injury for treatment group and after one week for control group. The thickness of RNFL was observed by optical coherence tomography.

Results:

All surgeries were conducted successfully, without severe complications. The best corrected visual acuity of treatment group surpassed that of control group one month after surgery, and treatment group had an obviously higher overall effective rate (95.0%) than control group did (81.7%). The incidence rate of postoperative complications in treatment group (6.7%) was significantly lower than that of control group (28.3%) (P<0.05). Logistic multivariate regression analysis showed that vitrectomy timing and postoperative complications were independent risk factors of prognosis (P<0.05). Both groups had significantly thinner RNFLs one week after surgery (P<0.05), and treatment group almost recovered within one month (P>0.05).

Conclusion:

Early vitrectomy effectively augmented the visual acuity of patients with TON, decreased complications, affected RNFL thickness reversibly, and improved prognosis.