Objective assessment of YAG laser vitreolysis in patients with symptomatic vitreous floaters

No side effects on rabbit retina or vitreous microenvironment by nd:YAG laser vitreolysis

BACKGROUND

To explore the safety of Neodymium:Yttrium-aluminum-garnet (Nd:YAG) laser vitreolysis based on the histological examination of the retina and the alteration of vitreous cytokines in the rabbits.

METHODS

Nine male New Zealand rabbits underwent Nd:YAG laser vitreolysis of 10 mJ x 500 pulses in the left eyes, while the right eyes were used as controls. Intraocular pressure, color fundus photography, and ultrasound B scan were measured before, as well as 1 day, 4 weeks, and 12 weeks after Nd:YAG laser vitreolysis. Three rabbits were euthanized 1 day, 4 weeks, and 12 weeks after treatment, respectively. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and hematoxylin-eosin (H&E) staining were used to look for pathological changes in the retina. An enzyme-linked immunosorbent assay (ELISA) was utilized to detect the expression of vascular endothelial growth factor (VEGF) and some inflammatory cytokines, including interferon inducible protein 10 (IP-10), monocyte chemoattractant protein 1 (MCP-1) and interlenkin 6 (IL-6) in the vitreous humor. The ascorbic acid (AsA) and total reactive antioxidant potential (TRAP) in the vitreous humor were also measured.

RESULTS

Following Nd:YAG laser vitreolysis, the levels of VEGF, IP-10, MCP-1, IL6, AsA, and TRAP in the vitreous humor did not change substantially (P > 0.05). There were no detectable pathological changes in the retinal tissues, and no apoptotic signal was found.

CONCLUSIONS

Rabbits tolerate Nd:YAG laser vitreolysis without observable impact on retinal tissue or the microenvironment of the vitreous.

Long-term efficacy and safety of YAG laser vitreolysis for vision degrading myodesopsia

AIM

To assess the long-term efficacy and safety of yttrium-aluminum garnet (YAG) laser vitreolysis for vision degrading myodesopsia (VDM) caused by posterior vitreous detachment (PVD).

METHODS

This retrospective study reviewed VDM patients of PVD type undergoing YAG laser vitreolysis. The baseline demographic information, the patterns of floaters, the number of floaters, and the subjective improvement of floater sympotoms (ranging from 0 to 100%) from medical records were collected. Significant improvement was defined as a relief of floater symptoms of ≥50% at the final visit. The long-term efficacy and safety of YAG laser vitreolysis were analyzed. The risk factors linked to significant improvement of floater symptoms were defined using univariate and multivariate logistic regression analyses.

RESULTS

The final analysis included 221 patients with VDM. The mean age of patients was 61.08±7.74y, and the mean length of follow-up was 21.38±5.61mo. Totally 57.01% of patients experienced a significant improvement in their floater symptoms after YAG laser therapy, and none of them developed delayed retinal abnormalities such as retinal tears or detachments. Age (OR=1.049, 95%CI=1.007-1.092, P=0.021) was identified as a significant risk factor for significant improvement in VDM.

CONCLUSION

YAG laser vitreolysis is an effective and secure treatment for PVD-type VDM, and patients of advanced age are more likely to get favorable outcomes.

Vision degrading myodesopsia assessed with optos ultra-widefield scanning laser ophthalmoscope

BACKGROUND

To investigate the diagnostic sensitivity of Optos imaging for vision degrading myodesopsia (VDM).

METHODS

A total of 420 eyes from 345 patients with VDM were collected in this cross-sectional study. All eyes were classified as having posterior vitreous detachment (PVD) or not having PVD. The sensitivity of Optos imaging for the visibility of vitreous floaters was evaluated. The associated factors with the visibility of vitreous floaters on Optos images were analyzed in univariate and multivariate logistic regression analyses.

RESULTS

The mean age of all patients was 56.19 ± 13.89 years old, and 66.67% of patients were female. The vitreous floaters were visible on the ultrasound B scan in all eyes, but only in 47.62% of Optos images (55.29% in eyes with PVD and 15% in eyes without PVD). In the multiple binary logistic regression analysis, age (OR = 1.094, 95%CI = 1.063-1.125, P < 0.001), spherical equivalent (OR = 0.869, 95%CI = 0.791-0.955, P = 0.004) and the distance of the floaters from the retina (OR = 1.191, 95%CI = 1.059-1.339, P = 0.003) were significantly correlated with the visibility of vitreous floaters on Optos images. On Optos images, 25.71% of VDM eyes presented additional retinal abnormalities.

CONCLUSIONS

Optos imaging has a low sensitivity for vitreous floaters, particularly in eyes without PVD. On Optos imaging, floaters were more visible in older patients, eyes with greater myopia, and floaters that were further from the retina.

Practical applications of vitreous imaging for the treatment of vitreous opacities with YAG vitreolysis

PURPOSE

To demonstrate the methodology and efficacy of using scanning laser ophthalmoscopy (SLO) and dynamic optical coherence tomography (OCT) to identify and treat symptomatic vitreous floaters using yttrium-aluminum garnet laser vitreolysis (YLV).

METHODS

This is a case series highlighted from a cross sectional retrospective study conducted at the Vitreous Retina Macula Specialists of Toronto. Forty eyes from thirty-five patients were treated with YLV between November 2018 and December 2020 for symptomatic floaters and imaged with SLO and dynamic OCT. Patients were re-treated with YLV if they reported ongoing significant vision symptoms during follow-up which correlated to visible opacities on exam and or imaging. Three cases will be highlighted to present the practical applications of SLO and dynamic OCT imaging for YLV treatment.

RESULTS

Forty treated eyes were enrolled in this study, with twenty-six eyes (65%) requiring at least one repeat YLV treatment following the first treatment due to ongoing symptomatic floaters. Following the first YLV, there was a significant improvement in overall mean best corrected visual acuity compared to before treatment (0.11 ± 0.20 LogMAR units vs. 0.14 ± 0.20 LogMAR units, p = 0.02 (paired t test)). Case 1 demonstrates a dense, solitary vitreous opacity that has been localized with dynamic OCT imaging to track its movements and retinal shadowing with the patient's eye movements. Case 2 shows the utility of adjusting the fixation target to monitor the movement of vitreous opacities in real-time. Case 3 exhibits an association between decreased symptom burden and vitreous opacity density after YLV.

CONCLUSION

Image-guided YLV facilitates the localization and confirmation of vitreous opacities. SLO and dynamic OCT of the vitreous can provide a real-time evaluation of floater size, movement, and morphology, to help clinicians target treatment and monitoring of symptomatic floaters.

Patient-reported outcomes in patients with vitreous floaters: A systematic literature review

Seeking treatment for bothersome vitreous floaters is patient driven. To measure the impact of floaters and treatment on an individual's quality of life, patient-reported outcome measurements (PROMs) are essential. We review all studies using a PROM for patients with floaters. We evaluated content coverage against quality-of-life domains previously identified in other ophthalmic disorders, and against a qualitative study investigating quality-of-life issues in patients with floaters. We assessed measurement properties of PROMs using an extensive range of psychometric quality criteria. We identified 59 studies using 28 different PROMs. Many PROMs were not specifically developed for patients with floaters. Floater-specific PROMs were mostly based on content validation from an ophthalmologist or researcher perspective; two included a patient perspective. Using the outcomes of the qualitative study, we found that the floater-specific PROMs were narrow in their content coverage, with most items relating to visual symptoms and activity limitations. Testing the psychometric quality of PROMs was rare, and when employed mostly limited to responsiveness and known group validity. The remarkable high number of floater-specific PROMs reveals a need for such measurements in ophthalmology. Unfortunately, reporting on psychometric quality is limited, and content development is most often done without patient involvement.

THE WAY PATIENTS SEE FLOATERS: Widefield Dynamic Scanning Laser Ophthalmoscopy Imaging of Vitreous Abnormalities

PURPOSE

To investigate the use of dynamic widefield scanning laser ophthalmoscopy (SLO) and B-scan ultrasonography in imaging vitreous abnormalities in patients with complaints of floaters.

METHODS

Twenty-one patients underwent both dynamic SLO and B-scan ultrasonography to image their vitreous abnormalities. After reviewing these videos, patients graded each imaging technique on a scale of 1 to 10, based on how closely it represented their visual perception of floaters.

RESULTS

The mean age of the patients (12 women and nine men) was 47.7 ± 18.5 years. The patients graded a median score of nine for SLO imaging (mean = 8.43) compared with a median score of 5 (mean = 4.95) for ultrasound ( P = 0.001). Widefield SLO imaging demonstrated three-dimensional interconnectivity within the condensations of the formed vitreous that exhibited translational and rotational movements with eye saccades.

CONCLUSION

Floaters are a common complaint, but it is difficult to know whether imaging findings of the vitreous correlate to what patients perceive. Widefield SLO seems to image vitreous abnormalities related to how patients perceive their own floaters better than B-scan ultrasonography. Despite the term "floaters", the vitreous abnormalities in the videos seemed to be manifestations of a complex three-dimensional degeneration of the vitreous framework.

Forms of Ocular Larval Toxocariasis in Childhood. A Review

The aim of this paper is to present an outline of forms of ocular manifestations of visceral larva migrans in children, as illustrated by the extensive photographic documentation. Ocular larval toxocariasis (OLT) has various clinical manifestations even in childhood age, in which age representation has an influence. The most common is presence of peripheral granuloma of the eye, frequently with a tractional vitreal streak leading from the retinal periphery to the optic nerve papilla. This is followed by granuloma of the posterior pole of the eye, usually reaching from the macular landscape to the central retinal periphery, always with vitritis. In children OLT may be manifested also in affliction of the optic nerve (cystic granuloma of the head of the optic nerve or neuropathy with vitreal reaction), fulminant endophthalmitis and in rare cases also diffuse chorioretinitis. The diagnosis rests upon a clinical ophthalmological finding, as well as laboratory examination of the levels of antibodies with potential eosinophilia. Histological examination may demonstrate spherical polypoid ossification in the choroid at the posterior pole of the eye as a consequence of fibrotisation and calcification, proceeding from the surrounding area of the absorbed larva. General combined treatment with antihelminthics and corticosteroids is arduous and does not always produce the desired effect in the sense of a satisfactory improvement of visual acuity. In differential diagnostics, manifestations of OLT in small children are still associated with retinoblastoma and a clinical picture of other intraocular diseases.

Spontaneous remission of vision degrading myodesopsia of posterior vitreous detachment type

PURPOSE

The study aims to observe the spontaneous remission of posterior vitreous detachment (PVD)-type vision degrading myodesopsia (VDM) during long-term follow-up.

METHODS

We retrospectively reviewed VDM patients with PVD type that refused any treatment. The ratio and time of significant spontaneous remission of floater symptoms occurring were described. The associated factors with significant remission of floater symptoms were analyzed in the univariate and multivariate logistic regression analyses.

RESULTS

In total, 179 patients with VDM were assessed. The mean age of all patients was 60.56 ± 0.47 years old, and the mean duration of follow-up was 23.89 ± 6.63 months. Of the patients, 40.78% have significant improvement in their floater symptoms after mean 16.55 ± 10.63-month follow-up. Myopia (OR = 0.280, 95% CI = 0.084-0.932, P = 0.038), the number of floaters > 3 (OR = 0.343, 95% CI = 0.172-0.683, P = 0.002), and floaters with string-like pattern (OR = 0.370, 95% CI = 0.166-0.824, P = 0.015) and blocky pattern (OR = 0.299, 95% CI = 0.090-0.993, P = 0.049) were negatively correlated with the significant spontaneous remission of VDM symptoms in the multiple binary logistic regression analysis.

CONCLUSIONS

Approximately 40% of VDM patients with PVD may experience significant spontaneous remission during long-term follow-up. Patients that are non-myopic and with fewer floaters are more likely to feel relief from VDM symptoms. Floaters with string-like or blocky patterns are less likely to undergo spontaneous remission.

A New Pharmacological Vitreolysis through the Supplement of Mixed Fruit Enzymes for Patients with Ocular Floaters or Vitreous Hemorrhage-Induced Floaters

Purpose: Ocular floaters caused by vitreous degeneration or blood clots may interfere with various visual functions. Our study investigated the pharmacologic effects of oral supplementation of mixed fruit enzymes (MFEs) for treating spontaneous symptomatic vitreous opacities (SVOs) and those secondary to vitreous hemorrhage (VH). Methods: 224 patients with monocular symptomatic vitreous opacities (SVOs) were recruited between September and December 2017 and received oral supplementation of MFEs (190 mg bromelain, 95 mg papain, and 95 mg ficin) for 3 months in a double-blind clinical trial. Participants were divided according to the etiology of the SVOs, spontaneous (experiment 1) versus VH (experiment 2), and then randomly assigned into four treatments groups: one group received oral vitamin C, as a placebo; and the other 3 groups received 1 capsule per day (low dose), 2 capsules per day (middle dose), or 3 capsules per day (high dose) of MFEs. The number of SVOs was determined at baseline and then 1, 2, and 3 months after initiating treatment. Further, in cases secondary to VH, the changes in corrected distance visual acuity (CDVA) were assessed after 3 months. Second, we compared the free radical scavenging capabilities of each substance: vitamin C, bromelain, papain, ficin, and MFEs (combination of bromelain, papain, and ficin) by DDPH assay. Finally, SVOs-related symptoms and satisfaction with the treatments were evaluated at the last follow-up visit Results: In experiment 1, the disappearance rate of SVOs was 55%, 62.5%, and 70% after taking 1, 2, and 3 capsules daily, respectively (total p < 0.001), in a dose-dependent manner. In experiment 2, the disappearance rate of VH-induced SVOs was 18%, 25%, and 56% (p < 0.001) after 1, 2, and 3 capsules of the supplement daily, respectively. Additionally, the patients’ vision elevated from 0.63LogMAR to 0.19LogMAR (p = 0.008). Conclusions: A pharmacological approach using a high dose of oral supplementation with MFEs (bromelain, papain, and ficin) was effective in reducing vitreous opacities, even after intraocular hemorrhage. Furthermore, pharmacologic vitreolysis with MFEs supplementation showed high patient satisfaction, and also improved CDVA in patients with vitreous hemorrhage-induced floaters

Design of a Functional Eye Dressing for Treatment of the Vitreous Floater

With the rapid development of display technology, related diseases of the human eye are also increasing day by day. Eye floaters are one of the diseases that affect humans. Herein, we present a functional ophthalmic dressing that can permeate the skin tissues of the eyes through oxygen and hydrogen to improve the symptoms of floaters. In clinical tests, the symptoms of sensory floaters improved in 28 patients, and the recovery rates of mild, moderate, and severe floaters were about 70%, 66.7%, and 83.3%, respectively.

The effectiveness of laser vitreolysis for vitreous floaters in posterior vitreous detachment

Purpose

To determine the effectiveness of laser vitreolysis in terms of contrast sensitivity function (CSF) and vision-related quality of life (VRQol) for symptomatic floaters due to posterior vitreous detachment (PVD).

Materials

This is an interventional study that involved 57 eyes of 45 patients with symptomatic floaters for more than 3 months. Patients underwent one to three sessions of vitreolysis via Neodymiun-doped Yttrium Aluminum Garnet (Nd:YAG) laser. We examined the CSF using the computer programs Freiburg Acuity and Contrast Test (FrACT) and VRQoL survey using the National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25) before, and 1 month after, vitreolysis.

Results

Twelve patients had both eyes lasered and 33 patients had one eye lasered. The mean CSF improved from 3.20 ± 0.85%W to 2.64 ± 0.63%W 1 month after vitreolysis. Each use of the laser showed a significant mean difference in CSF (%W) as analyzed by paired t-test before and after the first laser (0.29 ± 0.49%W [P ≤ 0.001]); after the first and second laser (0.35 ± 0.53%W [P = 0.01]); and after second and third laser (0.21 ± 0.31%W [P = 0.02]). There was improvement in the median of four subscales in NEI VFQ-25 scores post treatment: general vision (z = -3.30, P = 0.001), near activity (z = 3.396, P = 0.001, distance activity (z = -2.788, P = 0.005), and mental health (z = -2.219, P = 0.026). The mean scores increased to 79.55 ± 9.45 from the baseline 75.06 ± 9.69 (P ≤ 0.001). No adverse events were recorded 1 month after the laser treatments.

Conclusion

Vitreolysis by Nd:YAG laser improved the CFS and VRQoL in symptomatic PVD patients.

The Efficacy and Safety of YAG Laser Vitreolysis for Symptomatic Vitreous Floaters of Complete PVD or Non-PVD

INTRODUCTION

To evaluate and compare the efficacy and safety of YAG laser vitreolysis in treating symptomatic vitreous floaters of complete posterior vitreous detachment (PVD) and non-PVD.

METHODS

In this prospective cohort study, 51 eyes with symptomatic floaters were treated with YAG laser vitreolysis. Participants were divided into complete PVD and non-PVD groups. Objective visual quality measures including the Strehl ratio (SR), internal spherical aberration (SA), internal comatic aberration (CA), internal high-order aberration (HOA), area ratio of modulation transfer function (MTFa) and Vitreous Floaters Symptom Questionnaire (VFSQ-13) scores were used to compare the efficacy of YAG laser vitreolysis treatment between two groups.

RESULTS

The mean age of all patients was 56.80 ± 10.82 years old. In total, 36 of 51 (70.59%; 95% CI 58.10-83.10) patients reported their symptoms as significant or complete improvement after YAG laser vitreolysis treatment. Post-treatment MTFa, internal SA and internal HOA were significantly better compared to baseline (26.19 ± 14.73 vs. 29.19 ± 17.98, p = 0.013; 0.05 ± 0.05 vs. 0.04 ± 0.04, p = 0.031 and 0.23 ± 0.22 vs. 0.16 ± 0.07, p = 0.044; respectively) in all eyes. Twenty-nine of 51 (56.86%) eyes had floaters of non-PVD type. Significant or complete subjective improvements in the PVD group and non-PVD group were 72.73% and 68.97% (p = 0.344), respectively.

CONCLUSIONS

Improved subjective and objective visual quality in participants with symptomatic floaters following YAG laser vitreolysis was found in both groups. The efficacy of YAG laser vitreolysis was comparable in floaters of complete PVD and non-PVD types.

Vitreous function and intervention of it with vitrectomy and other modalities

The vitreous body, the largest intraocular component, plays a key role in eye development, refraction, cell barrier function, oxygen metabolism and the pathogenesis of assorted diseases. Age, refraction and systemic diseases can cause vitreous metabolic abnormalities. With the continuous development of vitrectomy techniques and equipment, vitreous injections and vitrectomies have increased over the recent decades. However, the normal oxygen tension gradient in the vitreous helps to protect the lens and anterior chamber angle from oxidative stress damage, whereas the increased vitreous oxygen tension around lens and the trabecular meshwork after vitrectomy may lead to postoperative nuclear cataract and a high incidence of open angle glaucoma. As a conventional procedure, scleral buckling holds several advantages over vitrectomy in selected cases. This review raises concerns regarding the function of the vitreous, and encourages conducting vitreous interventions prudently.

Livelayer: a semi-automatic software program for segmentation of layers and diabetic macular edema in optical coherence tomography images

Given the capacity of Optical Coherence Tomography (OCT) imaging to display structural changes in a wide variety of eye diseases and neurological disorders, the need for OCT image segmentation and the corresponding data interpretation is latterly felt more than ever before. In this paper, we wish to address this need by designing a semi-automatic software program for applying reliable segmentation of 8 different macular layers as well as outlining retinal pathologies such as diabetic macular edema. The software accommodates a novel graph-based semi-automatic method, called "Livelayer" which is designed for straightforward segmentation of retinal layers and fluids. This method is chiefly based on Dijkstra's Shortest Path First (SPF) algorithm and the Live-wire function together with some preprocessing operations on the to-be-segmented images. The software is indeed suitable for obtaining detailed segmentation of layers, exact localization of clear or unclear fluid objects and the ground truth, demanding far less endeavor in comparison to a common manual segmentation method. It is also valuable as a tool for calculating the irregularity index in deformed OCT images. The amount of time (seconds) that Livelayer required for segmentation of Inner Limiting Membrane, Inner Plexiform Layer-Inner Nuclear Layer, Outer Plexiform Layer-Outer Nuclear Layer was much less than that for the manual segmentation, 5 s for the ILM (minimum) and 15.57 s for the OPL-ONL (maximum). The unsigned errors (pixels) between the semi-automatically labeled and gold standard data was on average 2.7, 1.9, 2.1 for ILM, IPL-INL, OPL-ONL, respectively. The Bland-Altman plots indicated perfect concordance between the Livelayer and the manual algorithm and that they could be used interchangeably. The repeatability error was around one pixel for the OPL-ONL and < 1 for the other two. The unsigned errors between the Livelayer and the manual algorithm was 1.33 for ILM and 1.53 for Nerve Fiber Layer-Ganglion Cell Layer in peripapillary B-Scans. The Dice scores for comparing the two algorithms and for obtaining the repeatability on segmentation of fluid objects were at acceptable levels.

Current treatment strategies for symptomatic vitreous opacities

PURPOSE OF REVIEW

Symptomatic vitreous opacities are increasingly recognized as a significant burden to patient well-being. There is growing interest in the use of vitrectomy or laser treatment to address these problems. This review is intended to update current assessment, management, and risks of treatment for persistent severely symptomatic vitreous opacities.

RECENT FINDINGS

Despite studies showing the value of quantitative ultrasound, reading speed measurements, and contrast sensitivity for assessing dysfunction caused by vitreous opacities, the decision of whether to proceed with surgery remains a very subjective, clinical one. Visual Function Questionnaire-25 score studies show a very large improvement postvitrectomy consistent with relief from symptoms and patient satisfaction. The risk of retinal tear and detachment appears to be higher than in most conditions treated with vitrectomy.

SUMMARY

Vitrectomy for the management of severe vitreous opacities is increasingly accepted because of the tremendous relief of symptoms reported by patients. The risks of retinal tear and detachment remain a concern, particularly in patients who have an attached posterior hyaloid. Yttrium-aluminum-garnet laser treatment of floaters may offer benefit in a subset of patients but appears to be less definitive than vitrectomy, and also may carry significant risk.

Nd:YAG laser vitreolysis and health-related quality of life in patients with symptomatic vitreous floaters

BACKGROUND

The treatment of floaters has consisted primarily of monitoring. The therapeutic approach is based on surgical removal or Nd:YAG laser treatment. The objective of this study was the assessment of the quality of life in patients treated with Nd:YAG laser for floaters.

METHODS

Single-center pretest-posttest design in a cohort of subjects treated with Nd-YAG laser with Ultra Q-Reflex technology. Health-related quality of life of the patients was measured before and after the intervention with the Visual Function Questionnaires VFQ-25 and VFQ-39. Anxiety level was measured with the State-Trait Anxiety Inventory. Visual acuity, contrast sensitivity, and safety parameters were also considered.

RESULTS

Thirty-four patients were included in the study. For the VFQ-25 baseline, the median was 73.05, interquartile range (19.25) versus a final median value of 93.76 (8.73) with p < 0.01. The baseline median for the extended version VFQ-39 was 74.60 (19.01) versus the final median of 95.01 (6.50) with p < 0.001. Regarding the anxiety, according to the STAI questionnaire, there were statistically significant differences between the baseline and the final conditions, with a baseline median of 38 (11) versus a final median of 18 (19); p < 0.001. When the analyses differentiated between patients with and without myopia, there were statistically significant differences for VFQ-25 and VFQ-39.

CONCLUSIONS

This study shows an improvement in the health-related quality of life and a significant decrease in anxiety for patients that have undergone Nd: YAG Ultra-Q Reflex laser vitreolysis for floaters vaporization. The effect found is higher in myopic patients.

An optimized segmentation and quantification approach in microvascular imaging for OCTA-based neovascular regression monitoring

Background

Quantification of neovascularization changes in terms of neovascular complex (NVC) acquired from the optical coherence tomography angiography (OCTA) imaging is extremely important for diagnosis and treatment monitoring of proliferative diabetic retinopathy (PDR). However, only few vessel extraction methods have so far been reported to quantify neovascular changes in NVC with proliferative diabetic retinopathy PDR based on OCTA images.

Methods

Here we propose an optimized approach to segment blood vessels, which is based on an improved vascular connectivity analysis (VCA) algorithm and combined with morphological characterization and elimination of noise and artifacts. The length and width of vessels are obtained in the quantitative assessment of microvascular network. The feasibility of the proposed method is further studied by a treatment monitoring and statistical analysis process, as we have monitored and statistically analyzed the changes of NVC based on sampled OCTA images of PDR patients (N = 14) after treatment by intravitreal injection of conbercept.

Results

The proposed method has demonstrated better performance in accuracy compared with existing algorithms and can thus be used for PRD treatment monitoring. Following the PDR treatment monitoring study, our data has shown that from the 1st day to 7th day of treatment, the averaged (arithmetic mean) length of NVC has been substantially shortened by 36.8% (P < 0.01), indicating significant effects of treatment. Meanwhile, the averaged (arithmetic mean) width of NVC from the 1st day to 7th day of treatment has been increased by 10.2% (P < 0.05), indicating that most of the narrow neovascularization has been reduced.

Conclusion

The results and analysis have confirmed that the proposed optimization process by the improved VCA method is both effective and feasible to segment and quantify the NVC with lower noise and fewer artifacts. Thus, it can be potentially applied to monitor the fibrovascular regression during the treatment period.

Clinical Trial Registration This trial is registered with the Chinese Clinical Trial Registry (Registered 27 December 2017, http://www.chictr.org.cn, registration number ChiCTR-IPR-17014160).