Comparison of Peripapillary Choroidal Microvasculature Dropout in Primary Open-angle, Primary Angle-closure, and Pseudoexfoliation Glaucoma

Comparison of the Choroid in Primary Open Angle and Angle Closure Glaucoma Using Optical Coherence Tomography

PRCIS

The current study highlights distinct choroidal alterations in primary open angle (POAG) and primary angle closure (PACG) glaucomas, underscoring the potential of the Choroidal Vascularity Index (CVI) as a valuable indicator for understanding glaucoma pathogenesis.

PURPOSE

To evaluate choroidal structural changes in patients with POAG and PACG and healthy controls utilizing the CVI and subfoveal choroidal thickness by enhanced depth imaging optical coherence tomography.

METHODS

This study was cross-sectional. A total of 171 eyes of 171 subjects, comprising 69 eyes with untreated POAG, 58 eyes with untreated PACG, and 44 healthy eyes, were enrolled in this study. Subfoveal choroidal thickness, luminal area (LA), stromal area (SA), and total choroidal area were measured on enhanced depth imaging-optical coherence tomography scans. The CVI parameter is calculated as the proportion of LA to the total choroidal area.

RESULTS

This study included 69 patients with POAG with a mean age of 51.4 ± 13.3 years, 58 patients with PACG with a mean age of 57.0 ± 7.3 years, and 44 healthy subjects with a mean age of 51.11 ± 10.7 years. The CVI in the POAG and PACG groups was significantly lower than that in the control group ( P = 0.001 and P = 0.005, respectively); however, not significantly different between the two glaucoma groups ( P = 1.000). POAG eyes had significantly lower LA than PACG and controls ( P = 0.014 and P = 0.049, respectively), whereas PACG eyes had significantly greater SA than controls ( P = 0.041).

CONCLUSIONS

The CVI of POAG and PACG eyes was significantly lower than that of normal eyes. A reduced LA was observed mainly in eyes with POAG, and an increased SA was observed mainly in eyes with PACG. The role of the choroid may differ between POAG and PACG eyes.

Parapapillary choroidal microvascular density in acute primary angle-closure and primary open-angle glaucoma: an optical coherence tomography angiography study

BACK GROUND/AIMS

To determine whether parapapillary choroidal microvasculature (PPCMv) density, measured by optical coherence tomography angiography, differed between acute primary angle-closure (APAC), primary open-angle glaucoma (POAG) and controls.

METHODS

This is a prospective, cross-sectional, observational study. Data from 149 eyes from two academic referral centres were analysed. Automated PPCMv density was calculated in inner and outer annuli around the optic nerve region in addition to the peripapillary superficial vasculature, using customised software. A generalised estimating equation was used to compare vessel densities among groups, adjusted for confounders.

RESULTS

Data from 40 eyes with APAC, 65 eyes with POAG and 44 eyes in healthy controls were gathered and analysed. Global radial peripapillary capillary densities were reduced in eyes with APAC and POAG compared with controls (p=0.027 and 0.136, respectively). Mean outer annular PPCMv density in the POAG group was lower vs the APAC group by 3.6% (95% CI 0.6% to 6.5%) (p=0.018) in the multivariable model adjusted for confounders. The mean difference in inner and outer superior PPCMv between the POAG and APAC groups was 5.9% and 4.4% (95% CI 1.9% to 9.9% and 1.0% to 7.7%, respectively; both p<0.010). Furthermore, POAG and APAC groups both had significantly lower PPCMv compared with controls (both, p<0.001).

CONCLUSIONS

While superficial peripapillary vessels were affected to similar degrees in POAG and APAC, PPCMv drop-out was greater with POAG versus APAC, suggesting that choroidal vessel density may be affected to a lesser extent following an acute increase in intraocular pressure before glaucoma develops.

Choroidal Microvasculature Dropout in Glaucoma

Glaucoma is a group of diseases characterized by distinctive visual field defect and optic nerve atrophy usually associated with elevated intraocular pressure (IOP). It is one of the most serious visual disorders and the leading cause of irreversible blindness worldwide. As a multifactorial disease, the pathogenesis of glaucoma is complicated and has been far from fully understood, where vascular factors are recognized to play an important role in its development and progression of glaucoma. Empirical researches have shown that parapapillary choroidal microvasculature dropout (CMvD) is closely associated with the impairment of optic nerve head (ONH) perfusion, probably accelerating the progression of glaucoma. Accordingly, it is necessary to explore the details regarding the relationship between CMvD and glaucoma progress, hoping to enhance the understanding of pathogenesis of glaucoma. In this review, we aimed to establish comprehensive understanding of the relationship between CMvD and glaucoma with generally going through relevant up-to-date literatures. Among the events that are closely associated with CMvD, we summarized the ones specifically involved in the term of glaucomatous pathological process, including thickness of retinal nerve fiber layer (RNFL) thickness, lamina cribrosa (LC) morphology, cricumpapillary vessel density (cpVD) and visual function such as visual field (VF) defect as well as the prognosis of glaucoma. Although researchers have made great advances, there are still many issues need to be addressed particularly concerning the pathogenic role of CMvD in glaucoma development and its clinical implications with respect to glaucoma prognosis.

Change of Choroidal Microvasculature Dropout After Trabeculectomy as Assessed by Optical Coherence Tomography Angiography

PRCIS

Reduction in the angular circumference of choroidal microvascular dropout (CMvD AC) was found in POAG patients after trabeculectomy. Greater percentage of IOP reduction was significantly associated with decreased CMvD AC.

PURPOSE

The purpose of this study was to investigate the change of choroidal microvasculature dropout (CMvD) after trabeculectomy and its associated factors in primary open angle glaucoma (POAG) eyes using optical coherence tomography angiography.

METHODS

Fifty eyes of 50 POAG participants who had preoperative CMvD and underwent trabeculectomy were prospectively enrolled. Angular circumference (AC) of CMvD was determined from choroidal layer images by optical coherence tomography angiography preoperatively and at postoperative 1 year. The cutoff for significant AC of CMvD decrease was determined by the Bland-Altman method, and accordingly, patients were divided into 2, decreased and stable/increased CMvD AC groups. Changes in intraocular pressure (IOP) and CMvD AC were compared between the groups preoperatively and at postoperative 1 year. Factors associated with CMvD AC decrease were assessed by linear regression analysis.

RESULTS

The cutoff for significant CMvD AC decrease was 3.58 degrees; accordingly, 26 eyes (52.0%) were categorized as decreased CMvD AC group. No significant intergroup differences in baseline characteristics were found. However, the decreased CMvD AC group presented significantly lower IOP (10.7±3.7 vs. 12.9±2.6 mm Hg, P =0.022), lower CMvD AC (32.03±33.95% vs. 53.44±39.33%, P =0.044), and higher parapapillary choroidal vessel density ( P =0.014) compared with the increased/stable CMvD AC group at postoperative 1 year. The greater percentage of IOP reduction was significantly associated with decreased CMvD AC ( P =0.046).

CONCLUSIONS

CMvD AC reduction associated with IOP lowering was found after trabeculectomy. The long-term clinical relevance of postoperative CMvD reduction should be further investigated.

Optic nerve head vessel density using OCTA in patients with primary angle closure disease: A systematic review and network meta-analysis

PURPOSE

Elevated intraocular presure secondary to angle closure in angle closure glaucoma is considered the primary mechanism in the development of optic nerve damage. There is evidence that vascular mechanisms may play a role in the pathogenesis of primary angle closure disease (PACD). We aimed to evaluate optic nerve head vessel density in PACD.

METHODS

PubMed, Scopus, and Web of Science were searched. Observational investigations were included. A frequentist network meta-analysis was performed. The primary outcome was circumpapillary vessel density (cpVD), and the secondary outcome was peripapillary retinal nerve fiber layer (pRNFL) thickness.

RESULTS

One thousand twenty four eyes from eleven studies were included in the study. There was no difference in cpVD between the primary angle closure glaucoma (PACG) and acute primary angle closure (APAC) group however, there was a significant decreasing in pRNFL thickness in the PACG group compared to APAC group. In the PACG and APAC group, cpVD and pRNFL thickness were decreased compared to primary angle closure (PAC), primary angle closure suspect (PACS), and control group. There was no difference in cpVD and pRNFL thickness between PAC, PACS and control group.

CONCLUSION

This study has shown that the elevated intraocular pressure is an important factor affecting optical nerve perfusion in PACD. The decreasing in cpVD and RNFL thickness was more severe in the PACG and APAC group.

Microvascular Alterations of Peripapillary Choriocapillaris in Young Adult High Myopia Detected by Optical Coherence Tomography Angiography

(1) Background: The microstructural alterations of the peripapillary choriocapillaris in high myopes remain elusive. Here, we used optical coherence tomography angiography (OCTA) to explore factors involved in these alterations. (2) Methods: This cross-sectional control study included 205 young adults' eyes (95 with high myopia and 110 with mild to moderate myopia). The choroidal vascular network was imaged using OCTA, and the images underwent manual adjustments to determine the peripapillary atrophy (PPA)-β zone and microvascular dropout (MvD). The area of MvD and the PPA-β zone, spherical equivalent (SE), and axial length (AL) were collected and compared across groups. (3) Results: The MvD was identified in 195 eyes (95.1%). Highly myopic eyes exhibited a significantly greater area for the PPA-β zone (1.221 ± 0.073 vs. 0.562 ± 0.383 mm², p = 0.001) and MvD (0.248 ± 0.191 vs. 0.089 ± 0.082 mm², p < 0.001) compared with mildly to moderately myopic eyes, and a lower average density in the choriocapillaris. Linear regression analysis showed that the MvD area correlated with age, SE, AL, and the PPA-β area (all p < 0.05). (4) Conclusions: This study found that MvDs represent choroidal microvascular alterations in young-adult high myopes, which were correlated with age, SE, AL, and the PPA-β zone. In this disorder, OCTA is important for characterizing the underlying pathophysiological adaptations.

Effect of Intraocular Lens Biomaterials on the Treatment of Primary Angle Closure Glaucoma

To explore the effect of phacoemulsification along with intraocular lens (IOL) implantation on the treatment of primary angle closure glaucoma (PACG), a total of 50 patients (54 eyes) with PCG who had undergone surgery were selected as the research objects, in which, there were 16 eyes with the acute PACG in pre-clinical stage, 20 eyes with acute PACG during acute attack, and 18 eyes with chronic PACG, and all patients received phacoemulsification along with IOL implantation therapy. The patient’s best corrected visual acuity, anterior chamber (AC), anterior depth, intraocular pressure (IOP), visual field, and fundus conditions were measured during the operation, after the operation, and during the follow-up period. The postoperative visual acuity of the patients with three types of PACG was greatly corrected, in which 30 eyes had corrected visual acuity above 0.5, and there were statistically significant differences (SSDs) (P < 0.05); angle closure of 54 eyes had different degrees of improvement, the opening degree of the acute angle closure is better than that of the chronic angle closure, and there were SSDs (P < 0.05); each of 54 eyes showed different degrees of deepening in the central AC, and there were SSDs (P < 0.05); postoperative IOP decreased greatly in all 54 eyes, and there were SSDs (P < 0.05). In conclusion, the IOL implantation based on phacoemulsification can effectively treat the PACG, at the same time reduce IOP, promote angle opening, enhance vision field of the patients, and ultimately achieve the purpose of improving surgical success.

Posterior ocular structural changes and glaucoma susceptibility in patients with hemifacial spasm

PURPOSE

To evaluate the changes in the posterior ocular structures and glaucoma susceptibility in patients with hemifacial spasm (HFS).

STUDY DESIGN

Prospective observational clinical study.

METHODS

This study included 46 long-standing HFS patients with a minimum follow-up of 12 months. The participants' eyes were divided into three groups: (1) 46 affected eyes of patients with clinical HFS; (2) 46 unaffected fellow eyes and, (3) 46 eyes of healthy sex and age-matched controls. All participants were assessed by a detailed clinical examination and optical coherence tomography (OCT) with enhanced depth imaging (EDI). EDI-OCT images were binarized using ImageJ software. Peripapillary retinal nerve fiber layer (RNFL), ganglion cell complex (GCC), choroidal thickness (CT), and choroidal vascularity index (CVI) were used to compare the structural characteristics of the affected eyes with fellow and control eyes. The CT measurements were performed from the subfoveal and locations at 750 μm and 3000 μm intervals from the foveal center, and the average of CT measurements at 5 locations was accepted as mean CT.

RESULTS

The demographic and clinical characteristics among the groups were similar (for all, P > 0.05). Mean peripapillary RNFL thickness of the inferior quarter was significantly lower in affected eyes, compared to fellow eyes (P = 0.023) and control eyes (P = 0.040). Mean GCC thickness significantly decreased in affected eyes, compared to fellow eyes (P = 0.019) and healthy controls (P = 0.008). Mean CT thickness significantly decreased in affected eyes, compared to fellow eyes (P = 0.002) and healthy controls (P < 0.001). Mean subfoveal CVI (65.94% ± 1.46) was found to be significantly thinner than the unaffected fellow (68.19% ± 1.84, P = 0.011) eyes and control eyes (67.23% ± 0.84, P = 0.044).

CONCLUSIONS

This study's outcomes show that long-standing HFS is associated with glaucoma-associated morphological OCT findings and decreased both CT and subfoveal choroidal vascularity. These findings may be related to the fact that the posterior ocular structures are affected by long-lasting paroxysmal orbicularis contractions.

Choroidal vascularity index in pseudoexfoliative glaucoma

PURPOSE

To evaluate choroidal vascular involvement in pseudoexfoliative glaucoma (PEXG) by applying the choroidal vascularity index (CVI) to optic coherence tomography (OCT) images.

METHODS

Seventy-eight eyes from 40 subjects were included the study. Group 1 included healthy eyes (n = 20), group 2 eyes with PEX (n = 16), and group 3 eyes with PEXG (n = 42). OCT imaging of macular and peripapillary regions and retinal nerve fiber layer (RNFL) analyses were performed. CVI was calculated using ImageJ software.

RESULTS

The mean age was 64.89 ± 5.8, 71.2 ± 7.8, and 68.24 ± 7.4 years in groups 1, 2, and 3, respectively (p = 0.046). There were no significant differences between the groups in terms of sex (p = 0.777). In macula, mean CVI rates were 66.97 ± 1.9%, 64.23 ± 1.2%, and 64.63 ± 1.6%, and in the peripapillary areas, mean CVI rates were 67.04 ± 1.5%, 65.20 ± 1.5%, and 64.14 ± 2.1% in groups 1, 2, and 3, respectively (group 1 vs. group 2 and 3, p = 0.000; group 2 vs. group 3, p > 0.05). The decrease in average RNFL thickness was statistically significant in group 3 compared to groups 1 and 2.

CONCLUSION

CVI could be used to assess choroidal vascular changes in ocular diseases. CVI was found to be reduced in PEX and PEXG, indicating an ocular vascular involvement in pseudoexfoliative process.