A total of 47 patients with aqueous-deficient dry eye were included in this study. The results of the study showed that compared with before treatment, the OSDI scores of patients in the OASIS preloaded punctal plug treatment group and Smart Plug punctal plug treatment group were significantly improved 6 months after treatment. After treatment, the two groups of patients were similar in OSDI score, Schirmer I test, and BUT levels, and there was no significant difference.
Dry eye is a common and frequently occurring disease in ophthalmology [14]. Common symptoms include dry eyes, easy tiredness, itchy eyes, foreign body sensation, burning sensation, sticky discharge, fear of wind, photophobia, and sensitivity to external stimuli. Sometimes the eyes are too dry and there is not enough tear fluid, but it stimulates the secretion of reflex tears, causing frequent tears. In more serious cases, the eyes will be red and swollen, congested, keratinized, corneal epithelial defects, and filaments sticking. This kind of damage can cause corneal and conjunctival lesions over time and affect vision [15–17]. The International Dry Eye Workshop (DEWS) divides the disease into four grades according to its severity and treatment methods, and according to the different grades, it recommends the application of topical artificial tears, cyclosporine, tetracyclines, and lacrimal embolization [18].
In recent years, with the aging of the population, the use of electronic devices, and environmental factors, the number of patients with dry eye has been on the rise [19–22]. At present, there are various ways to treat dry eye, mainly including the elimination of incentives, artificial tear replacement therapy, preservation of own tears, promotion of tear secretion, further combining anti-inflammatory and immunosuppression, and surgical treatments [23–25]. However, general incentives are difficult to eliminate, and due to the complex composition of human tears, although there are various artificial tears for different tear film components, they still cannot completely replace their own tears. The side effects of immunosuppressive agents are large and cost much [26]. Moreover, long-term topical medication, the preservatives in the medication can easily cause damage to the ocular surface. If the dry eye patients need to use artificial tears frequently, such as more than 4–6 times a day; if the application of artificial tears has side effects or patients cannot tolerate or do not accept long-term drug treatment; if the drug treatment effect is poor or the symptoms cannot be completely solved by using artificial tears alone, lacrimal embolization can be adopted.
The first lacrimal plug used is a degradable punctum plug for the treatment of the severe dry eye. Nowadays, the lacrimal plug has developed a variety of shapes and materials, and its application is becoming more and more extensive. Lacrimal embolism can be divided into punctal plug and canaliculus embolism according to its location, and the time of their placement is divided into temporary and permanent embolism. Embolism is made of different materials, and current reports include collagen, silica gel, hydrogel, polydioxanone, and acrylic acid, etc. [27]. Generally speaking, when local lubrication cannot be improved, these small plugs improve the signs and symptoms of moderate dry eye. Permanent plugs have a longer residence time, so their impact is usually greater than that of temporary degradable plugs. Punctal plug are well tolerated, only about 10% need to be removed due to irritation. The literature shows that compared with the lacrimal canalicular plug, the lacrimal punctum plug has a higher probability of lacrimal overflow and plug body loss. Permanent punctal plug are more prone to side effects such as lacrimal canaliculitis and pyogenic granuloma. For a small number of patients, more invasive treatments are needed to remove them, such as lacrimal canalitomy and dacryocystorhinostomy.
Smart Plug punctal plug has been used for many years and is effective in the treatment of aqueous-deficient dry eye [10, 28]. The results of this study support the fact that Smart Plug punctal plug significantly improved subjective symptoms in patients with dry eye and prolonged BUT after surgery. However, Schirmer did not show significant improvement, presumably because punctal plug does not increase the secretion of the main and accessory lacrimal glands, thus increasing tear production. Instead, the symptoms of dry eye can be improved by reducing the limited tear drainage and increasing tear film stability. OASIS preloaded punctal plug is a new type of lacrimal duct plug, but high-quality clinical research articles are few currently. Our current study showed that that the OASIS preloaded punctal plug is comparable to the Smart Plug punctal plug in treating aqueous-deficient dry eye, and both can significantly improve dry eye symptoms. The OASIS preloaded punctal plug uses the device's own punctum dilator is a better match for the implant and reduces the risk of intraoperative overdilation of the lacrimal duct. Furthermore, it simplifies the surgical procedure, lacrimal punctum expansion and plug implantation can be completed in one step, the loss of embolization before implantation and the abnormal implantation due to the expansion of the embolic volume can be reduced, and minimize the risk of intraoperative complications. Therefore, it is worthy of clinical promotion.
Although the two kinds of lacrimal duct plugs had different degrees of postoperative complications, they were relieved by simple treatment, no serious irreversible complications occurred. Perhaps due to the short observation time, no canaliculus granuloma and canaliculitis requiring surgical treatment were observed. Whether there are serious complications in the later stage still needs Further observations.
This research still has the following shortcomings. First of all, although this study is a randomized controlled experiment, it is not blinded. Secondly, this study is a single-center clinical study, and the sample size included is relatively small. It is still necessary to increase the sample size and conduct multi-center clinical research. Finally, the clinical follow-up time of this study is relatively short, and long-term clinical follow-up observation is still needed.