It is well known that phacoemulsification combined with intraocular lens implantation is the most effective surgical method for cataract treatment at present. The complications of this operation are rare, but a small number of patients still have poor postoperative results, and macular degeneration may be the main reason. Studies have shown that during phacoemulsification, some posterior vitreous detachment or anterior displacement will occur, and the fovea macula and surrounding tissues will be pulled, resulting in edema or thickening.[10, 11] Other studies have reported that using the high perfusion mode during phacoemulsification can affect retinal thickness and blood flow and can even lead to the occurrence of early optic nerve ischemic lesions. It has been indicated that acute increases in IOP can induce ischemia-reperfusion injury, which may cause retinal ganglion cell death and damage to the optic nerve and retina.[13, 14] However, the effect of phacoemulsification on macular vessel density changes remains unclear.
As a new kind of quantitative measurement of ocular blood flow, OCTA’s measurement principle is in the same spot over retinal horizontal motion contrast scanning, and repeated scanning of certain areas of the fundus forms 3D data. These data, through multiple transverse scans, display structure changes and receive signals related to blood flow and blood cell movement. The results included all information regarding superficial retinal vessels, deep retinal vessels, and choroidal vessels. In addition, the SSADA algorithm is applied to improve the flow detection of the signal-to-noise ratio and the coherence of the capillary network. Another advantage of OCTA over conventional OCT is that 3D data images obtained after stratified scanning can show information at all levels of the retina, which helps in its detection and evaluation.7–8 As a non-invasive, non-injected contrast agent and time-free fundus vascular detection method, the purpose of this study was to measure the macular area, optic papillary omental thickness, and blood flow changes after phacoemulsification with OCTA quantification standard 2.0.
The results of this study suggested that the inner thickness in the macular region increased gradually after phacoemulsification, but the full thickness in the macular region decreased on the first postoperative day and followed an increasing trend. Three months postoperatively, the macular thickness increased significantly compared with before surgery. Yasuko et al. observed a macular thickness increase up to three months post-cataract surgery in both diabetic and non-diabetic eyes, which was mainly the result of an inflammatory response after cataract surgery.Our results were consistent with these. Likewise, Zhao et al. found that after phacoemulsification of cataract, the thickness of the macular area increased, was mainly confined to the inner layer, and still showed an increasing trend one and three months after surgery.Previous studies have shown that changes in retinal thickness after phacoemulsification are associated with rupture of the blood–retina barrier.[16–18]
This study showed that the thickness of the RNFL increased after phacoemulsification, and El-Ashry et al. reached a consistent conclusion. Studies have shown that high IOP compresses retinal blood flow and reduces blood supply, leading to ischemia and hypoxia of retinal ganglion cells and the fiber layer, the death of axons, and edema of the RNFL.[12, 20] In this study, IOP increased on the first day after surgery, followed by a decreasing trend. It was considered that transient IOP increased after phacoemulsification for cataract, resulting in increased nerve fiber layer thickness. Zhao et al. reported that the thickness of RNFL decreased on the first day after surgery, followed by an increasing trend. We also considered the influence of elevated acute IOP on macula thickness and RNFL.
Our study showed that after phacoemulsification for cataract, the vessel density in the superficial macula increased, while the change in the vessel density in the deep macula was not significant. The results of this study indicated that on the first postoperative day, most zones of superficial macular vessel density showed a decreasing trend, followed by an increasing trend, while most zones of deep macular vessel density continued to increase. It has been reported that increased macular perfusion after phacoemulsification is caused by macular functional congestion and speculated that this effect is caused by increased retinal light intensity stimulation after cataract extraction. These results suggest that ultrasonic emulsification has a greater clinical advantage in the elderly population.
This study showed that the whole image and inside disc blood flow had an increasing trend, but peripapillary vessel density had a decreasing trend. However, these trends were not statistically significant, which was consistent with the four-week clinical follow-up study by Karabulut et al., who reported a negative correlation between vascular density and IOP, which was confirmed at weeks one and four.Liu et al. revealed that the deep microvascular density in the parafovea and perifovea were increased, with enhanced pulsatile ocular blood flow after phacoemulsification, which might have attributed to the decreased mean IOP.In our study, IOP showed a trend of first increasing and then decreasing, while macular blood flow showed an opposite trend, suggesting a negative correlation.
This study monitored only changes in retinal thickness and blood flow density after phacoemulsification in the macular area and the papilla area of the optic nerve in early cataract. More data are needed to support this finding.
In conclusion, the results of this study indicate that macular thickness, inner retinal thickness, and RNFL decreased on the first day after phacoemulsification and then increased at one month and three months postoperatively. The vessel density in the deep macular and superficial layers, the whole image, and the inside disc vessel density increased, while the blood flow density in the peripapillary decreased. As a non-invasive method, OCTA provides a good guide when considering cataract surgery, especially in the elderly.