Liying Cheng, Lu Zhang, Xiaoming Sun, Xiyuan Mao, Liucheng Zhang, Yuguang Zhang,Ying Zhang

Department of Plastic and Reconstructive Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China

Keywords:Laser and light treatment Infraorbital Palpebral bags Lower eyelid Nonsurgical skin tightening Noninvasive fat reduction

ABSTRACT Laser and light treatments have recently become popular owing to its efficacy in treating laxity, rhytids, hyperpigmentation of the lower eyelids,and drooping of septum fat.For several decades,our department has explored the application of laser and light treatment for eye rejuvenation.This paper summarizes common treatment methods and analyzes the published literature on the indications and outcomes of multiple laser and light treatments for lower eyelid rejuvenation.An extensive survey of peer-reviewed literature was performed using PubMed, with the search terms “noninvasive treatment”, “infraorbital”, “palpebral bags”, “lower eyelid”, “radiofrequency(RF)”,“laser”,“nonsurgical skin tightening”,and“noninvasive fat reduction”.The results showed that the use of lasers, intense pulsed light (IPL), monopolar RF, bipolar RF, AdipoLASER rejuvenation (ALJ), and fractional RF microneedling are safe and effective treatments for palpebral bags.We conclude that using Qswitched lasers,IPL,RF,ALJ,and fractional RF microneedling is safe and effective for lower eyelid rejuvenation,with minimal complications and quick recovery.Further research and development of optoelectronic therapy may encourage breakthroughs in lower eyelid treatment,such as simplified complex surgery and noninvasive methods.

1.Introduction

The demand for noninvasive methods for body contouring and facial rejuvenation, specifically for the periorbital area, has grown exponentially over the last decade.In most periorbital cosmetic consultations,rhytids,hyperpigmentation of the lower eyelids,and drooping of septum fat are the three main complaints.Patients are concerned by a“fatigued”and aging facial appearance.Surgical procedures (transcutaneous or transconjunctival blepharoplasty) have been frequently performed to solve this problem.1Blepharoplasty addresses all layers of the lower lid:skin,orbital fat,orbicularis muscle,and sometimes the periosteum,thus providing long-term results.However, blepharoplasty might lead to prolonged recovery, ectropion, lateral canthal rounding, psychological issues, long-term erythema, and greater financial burden.As a result,many patients hesitate and forego surgery.

Currently, the global tendency is toward less aggressive procedures with minimal recovery for facial rejuvenation.Patients seek a less invasive approach without any downtime in recovery because of their active lifestyles and busy work schedules.As with other cosmetic treatments,an increasing number of patients seek noninvasive lower lid treatments to appear younger.It was noted on the plastic surgery statistics report in 2020 that the number of blepharoplasties is decreasing, while that of noninvasive treatments is increasing, compared to the statistics in the year 2000.Among the noninvasive treatments,laser and light treatments have become very popular,including ablation through laser resurfacing,2laser lipolysis,3chemical peeling,4intense pulsed light (IPL) therapy,5,6fractional RF,7AdipoLASER rejuvenation (ALJ),8and RF needling.9,10Majority of plastic surgeons have previously preferred surgical intervention; thus, only a limited number of studies on noninvasive treatments have been performed.

Laser and light treatments for the orbital area have undergone four periods of development: (1) visible light technologies, such as IPL, potassium titanyl phosphate laser, or pulsed dye laser that directly target dyschromia,flushing,and telangiectasias;(2)energy-based technologies that broadly ablate and/or heat a very superficial layer of the skin in a controlled manner (confluent beam CO2and erbium-doped yttrium aluminum garnet (Er:YAG); (3) fractional nonablative and ablative technologies; and (4) RF needling technologies.With improvements in techniques and devices, treatment results range from treating skin pigmentation to skin tightening and fat dissolving.11–13Such techniques have been proven effective for body contouring and skin tightening of the body and face.However, evidence regarding the treatment of the eye area and palpebral bags are very limited.To apply these techniques in the treatment of palpebral bags, we must understand the characteristics of the eye area and the etiology of palpebral bags.

The periorbital area presents a therapeutic challenge, because the eyelid skin is the thinnest part of the body yet serves an important function in protecting the eyes.The skin around the eyes has a very thin dermis(lower amount of collagen,elastin,and glycosaminoglycans than that of other areas of the face)and is very dry(low density of sebaceous glands) and inelastic, making the skin prone to discoloration, true pigmentation, and vascular dark circles.14With aging, collagen fibers become disorganized and elastic fibers become elastotic, allowing both gravity and the dynamics of the muscles and orbital fat to leave their mark on the dermal matrix and epidermal morphology, leading to sagging and laxity.Excessive skin laxity,hypertrophy or hyperactivity of the orbicularis muscle (infraorbital fat pseudoherniation), and prolapse of septum fat (infraorbital fat herniation) are the three etiologies of palpebral bag formation.Different laser and light treatments should be used depending on the presentation of the palpebral bags.However,the treatment of choice and its effectiveness have yet to be clarified.

Over the past few years, our group has extensively explored minimally invasive and noninvasive periorbital rejuvenation techniques,with minimal trauma and downtime.Venous infraorbital dark circles were decreased,and visible prominent veins were selectively removed using a long-pulsed 1 064-nm neodymium-doped YAG (Nd:YAG) laser.14In addition, since 2015, we have explored the use of the SmartLipo 1 064-nm system to remove herniated orbital fat tissue to improve lower eyelid appearance.This technique was shown to be a safe and minimal periorbital rejuvenation technique which reduces surgical trauma and shortens post-surgical recovery period.15Furthermore, we explored fractional nonablative and ablative technologies,as well as RF/RF needle technologies.Zhang et al.16found an effective route for the synergistic transdermal delivery of nanoethosomes embedded in hyaluronic acid nanogels when performing enhanced photodynamic therapy.Wu et al.17found that low-energy CO2fractional laser use in the treatment of early-stage pediatric hypertrophic scars is safe and effective.Yao et al.18applied Rose Bengal in lightly and darkly pigmented swine skin and were exposed to 532 nm to seal linear incisions(1.5 mm deep,2 cm long).The conclusion that sealing incisions using photochemical tissue bonding in moderately and highly pigmented skin requires a careful balance of irradiance and cooling.We believe that treatment with minimal invasion and critical precision is the final goal of periorbital rejuvenation.In this article,we focus on the following laser and light treatments performed on the periorbital area by differentiation and combination.

2.Intense pulsed light

IPL is used on the skin for vascular and pigment disturbances rather than wrinkle reduction.IPL is effective for palpebral bags accompanied by hyperpigmentation due to melanin or hemoglobin accumulation.19,20This treatment can clear irregular pigmentation, telangiectasias, and diffuse erythema using different wavelengths.IPL can also significantly improve skin elasticity.Compared with ablative laser devices, IPL treatment is safe, causes little discomfort, and is associated with a relatively low incidence of complications.However, studies regarding the treatment of eyelid hyperpigmentation with IPL devices are limited,and thus requires further exploration.

In 1976, Muhlbauer21first reported the use of polychromatic infrared light to treat vascular malformations.The photothermolysis of pigmented structures, cells, and organelles by selective absorption of pulsed radiation was described in detail in 1983.22In 1990, Goldman et al.23described a new high-intensity flash lamp as a suitable tool for treating vascular lesions, and IPL was launched commercially as a medical device in 1994.24IPL devices emit pulsed polychromatic high-intensity light from a flash lamp and a computer-controlled capacitor bank with wavelengths between 500 and 1 300 nm.Similar to that of lasers, the basic principle of IPL is the absorption of photons by endogenous or exogenous chromophores within the skin and transfer of energy to these chromophores.This transfer generates heat and subsequently destroys the target structure.Convertible cut-off filters allow for the selective targeting of chromophores, melanin, or hemoglobin to treat various pigment disorders.A study by Bjerring et al.25concluded that a 555–950-nm (variable length) filter was effective for clearing irregular pigmentation, while a 530–750-nm(perfect reconstruction) filter provided better results when treating telangiectasias and diffuse erythema (Ellipse Flex; Danish Dermatologic Development; laser emission-based microscope wavelength:530–750 nm or 555–950 nm; spot size: 10 mm × 48 mm; pulse duration: 22.5 milliseconds, delay: 10 or 8–20 milliseconds; fluence:6–20 J/cm2).

In a randomized controlled split-face trial evaluating skin rejuvenation by Hedelund et al.,26significant improvement in telangiectasia(P＜0.001)and irregular pigmentation(P＜0.03)were observed between IPL-treated and untreated sides (Ellipse Flex, Danish Dermatologic Development;laser emission-based microscope wavelength:530–750 nm;spot size: 10 mm × 48 mm; pulse duration: 22.5 milliseconds, delay:10 milliseconds; fluence: 7.5–8.5 J/cm2), but there was no significant difference for rhytids.

Cymbalista et al.5showed decreased melanin on histology and significant eyelid lightning, which was maintained for more than 1 year after IPL,but the authors also reported high incidences of post-procedure inflammation,hyperpigmentation,and hypopigmentation.Kołodziejczak et al.13showed that IPL can significantly improve skin elasticity and,to a lesser extent,erythema,and skin pigmentation.

The IPL treatment parameters in previous studies varied according to the treatment response of each patient: the energy density (fluence)ranged from 10 to 50 J/cm2, number of impulses was 1–5, impulse duration was 2–15 ms,impulse delay was 5–60 ms,and repeatability was 0.3–1 Hz.Moreover, the parameters were adjusted individually according to the patient’s Fitzpatrick phototype.The temperature of the glass transmission block did not exceed 458°C(Ash,Town,&Martin,2007).Usually,five successive IPL treatment sessions were performed at 2-week intervals.The greatest improvement in skin elasticity was observed between the first and second measurements.Mild discomfort may occur after IPL,such as redness,burning(visible up to 1 h after treatment),and tenderness (visible up to approximately 3–12 h after the treatment).Patients with hyperpigmentation sometimes experience darkening of their pigmented lesions,which may persist up to 7 days after treatment.

3.Q-switched lasers

Q-switched lasers deliver energy in nanosecond pulse durations,with the ability to target melanin, fat, and collagen.These devices include Nd:YAG(1 064 nm)and alexandrite(755 nm)lasers,and less commonly,ruby(694 nm)lasers.

Q-switched neodymium laser is well-known because it has a particular absorption wavelength for methemoglobin, hemoglobin, adipocytes, and the dermis.Weiss27first reported positive outcomes with a new multiple,synchronized-pulsed 1 064-nm laser for the treatment of leg telangiectasias and reticular veins in 1999,and confirmed that 75%improvement was achieved in majority of vessels with a diameter of 0.5–3 mm.Also, a wavelength of 1 064 nm is selective for the dermis, as it has absorption coefficients of 0.11 and 0.05 in the dermis and adipose tissue,respectively.The high absorption of the laser in the dermis promotes significant heating of tissue, leading to remodeling of collagen and reorganization of the papillary and reticular dermis.28In recent decades, the long-pulsed 1 064-nm Nd:YAG laser has been reported to be effective for infraorbital dark circles,and the SmartLipo 1 064-nm system has been used to reshape the face and body owing to its functions of lipolysis and tissue contraction.

Fig.1. Description of (A) superficial and (B) deep laser lipolysis treatments indicating the locations of treatment planes.

In contrast to the 1 320-nm wavelength, which concentrated energy around the laser fiber, the 1 064-nm wavelength has a more diffused distribution of energy targeting a greater area, and thus results in a greater degree of bulk heating.Treatments were delivered in two planes with the cannula in a reciprocating motion and a fan-like movement in the horizontal plane:superficial plane(approximately 3–5 mm below the skin surface,just below the junction of the deep dermis and the fat layer)(Fig.1A)and deep plane(approximately 20 mm below the skin surface,near the junction of the fat layer and the fascia)(Fig.1B).29

The SmartLipo 1 064-nm system benefits from hemostatic mechanisms and effects on tissue retraction; however,heating may also cause side effects; therefore, it should only be performed within a safe threshold.DiBernardo et al.29evaluated the tissue thermal effects from 1 064 nm laser-assisted lipolysis in abdominal skin,and found that surface temperatures exceeding47°C at 5 mmdepthtypicallycaused epidermal and dermal injury, with blistering above 58°C.Below this threshold, acute thermal effects may be linked to skin tightening during healing.Thus, they concluded that surface temperature stimulation should be at or slightly below 42°C.Deep tissue heating is recommended at 67–133 J/cm2or 1 675–3 325J ina 5-cmsection.With thinnerskinandsmallerfat layers,the periorbital skin is more susceptible to thermal injury from laser treatment;thus,this technique should be performed with great care.

Zhang et al.15analyzed 128 cases treated with the SmartLipo 1 064-nm system for protruding fat pads in the lower eyelid from April 2014 to May 2015.The Nd:YAG laser operates in the infrared portion of the spectrum (1 064 nm), with the photomechanical force and energy delivered via fiberoptics through a 1-mm cannula.A cannula with a 2-mm fiber outside the cannula was introduced into the septum slowly through the hole.The delivered laser parameters were 20 Hz and 3 W,and a duration of 5–10 s, and were done for 3–5 sessions.The mean corresponding accumulated laser energy was 450 J (range: 350–550 J).Prominent fat pads were scanned preoperatively and postoperatively to determine changes in size, and the mean follow-up duration was 8 months.The results showed that herniated orbital fat could be maximally corrected, but not completely.Most patients showed high satisfaction with an improved lower lid appearance.However, 10 patients (7%)comprising two men and eight women perceived no change on one or both sides after laser therapy.The reason for this might be the improper location of the laser target inside the orbital fat layer.All 10 patients underwent repeat laser treatment 3 months later and reported improved outcomes.Another histological study29using a scanning electron microscope showed that an increase in the irradiation of the adipose tissue in the treatment area produced greater fat destruction compared with areas receiving less irradiation.In addition to the effectiveness of SmartLipo in destroying subcutaneous fat, its hemostatic mechanisms,effects on tissue retraction, and collagen formation are more prominent benefits.

The ultimate goal of using SmartLipo 1 064-nm Nd:YAG laser is skin tightening.One of the main parameters for choosing a particular wavelength for a laser is the absorption of the wavelength for the four main tissue chromophores: methemoglobin, hemoglobin, adipocytes, and the dermis.In adipose tissue,the wavelength of 1 064 nm is selective for the dermis,as it has absorption coefficients of 0.11 in the dermis and 0.05 in adipose tissue, respectively.Other widely employed wavelengths (such as 924 nm)in laser-assisted lipolysis,which have absorption coefficients of 0.11 and 0.18 in the dermis and adipose tissue, respectively, are fatselective.The high absorption of the laser in the dermis promotes significant heating of the tissue,leading to remodeling of collagenous tissue and reorganization of the papillary and reticular dermis.

Multiple clinical trials and histological studies29,30have shown soft tissue retraction through coagulation of the collagen and reticular dermis when using the SmartLipo 1 064-nm platform.In a clinical study by Katz and McBean,30a marked area was treated with SmartLipo and measured 1 month after treatment to record the change in area.The authors noted an average decrease of 15% per treated area after using the SmartLipo system.A similar study by DiBernardo29showed a maximum 32%decrease in area and an increase in skin elasticity.The dermal coagulation properties of the SmartLipo system, combined with its lower complication rates,increases the number of contraindicated patients for traditional liposuction procedures.

4.Nonablative radiofrequency

Nonablative RF allows for tightening of the deep dermal structures without epidermal damage, and this method has been widely used to rejuvenate the skin;to treat skin wrinkles,skin laxity,atrophic scars,and acne scars; and to lift aging skin without surgery.31Nonablative RF devices use a unique capacitor membrane at the treatment tip,allowing for uniform and volumetric heat application.This method is commonly used with the application of the treatment tip directly over the orbital area or over a distal area (anchoring points) to contract the orbital area.The mechanism is likely a consequence of the thermal stimulation of fibroblasts to produce new collagen,cell mediators,and eventual contraction.Ruiz-Esparza32applied a nonablative RF device (ThermaCool TC; Thermage Inc., Hayward, CA) on the temporal and/or zygomatic areas once with one–three passes under topical anesthesia.The application of RF energy was outside the orbital rim and was lateral rather than inferior to the lower eyelid,which served as anchoring points to produce vectors of skin movement that eventually stretched the lax skin of the lower eyelids to produce clinical improvement.Settings were 12.5–14.5, which correspond to fluences between 79 and 112 J/cm2.Cosmetic improvement appeared at 5 weeks after treatment.All patients displayed some degree of tissue contraction, which stretched the lax skin of the lower eyelids, resulting in cosmetic improvement without complications.Postoperatively, there was no appreciable pain, edema, or erythema, as would be the case if a dermal thermal burn had been created.However,this technique has some limitations.Specifically, it does not correct fat herniation or muscle hypertrophy in the lower eyelid;thus,surgery may be preferred to address underlying problems and achieve better results.

5.Radiofrequency

RF therapy has shown high efficacy and safety in improving lower eyelid fat bulging.33,34RF devices use an electric current to create a thermal effect that results in collagen contraction and neocollagenesis,cell apoptosis,and fatty tissue reduction.35

5.1.Monopolar radiofrequency

Monopolar RF devices,such as those manufactured by Thermage,Inc.(Hayward, CA), successfully and noninvasively tighten the skin of the lower lid,upper and lower face,neck,arms,abdomen,and thighs.This is accomplished by thermal modification of dermal collagen and shortening of the fibrous septa extending from the dermis into the subcutaneous tissue.Holloman et al.33used monopolar RF in patients with eyelid skin laxity and mild to moderate dermatochalasis using a 0.25-cm2treatment tip.Treatment was administered from the eyelashes to the eyebrows superiorly and from the eyelashes to the orbital rim inferiorly, and included the “crow’s feet” region laterally.The range of treatment settings was 30.5(9 J)to 36.5(21 J),with a mean of 32(12 J).The majority of patients achieved up to 25%improvement with this treatment,while a smaller percentage achieved more dramatic results.

5.2.Bipolar radiofrequency

The radiofrequency-assisted liposuction (RFAL) technique is a promising technology for body contouring, with the following advantages:ability to heat a significant volume of tissue quickly and uniformly,ability to control tissue heating through direct monitoring of temperature and tissue impedance, defragmentation of fat cells and coagulation of blood vessels in the treated zone(thus reducing bleeding and bruising),obvious collagen denaturation after treatment, and significant contraction and retraction of adipose and dermal tissue after treatment.36,37Mulholland36performed RFAL in 20 patients and 40 lipoplasty zones under tumescent anesthesia.The RFAL body contour procedure was performed using the BodyTite system(Invasix Ltd.,Yokneam,Israel).The internal electrode was inserted into adipose tissue at the desired depth for adipose and blood vessel coagulation.This insulated internal electrode probe emits the RF current through a small conductive tip.The external electrode has a larger contact area and is applied to the skin surface, creating lower power density in the skin than in the adipose tissue.Up to 50 W of RF power was applied between the two electrodes.The RF power distribution between the electrodes is shown in Fig.2.The RF current creates heat and coagulates adipose, vascular, and fibrous tissues in the operative area(Fig.3).During treatment,the parameters of the BodyTite device were set so that the system would reach 40°C and maintain the target temperature for 1–2 min.The typical RF energy introduced into the treated area was 100 J/cm2.The uniformity of the temperature distribution was analyzed using thermal images and Researcher 2.9 of the Flir Systems software.No complications or long-term adverse effects were observed in any patient.Thus,RFAL is an ideal device for lipolysis and skin contracture of the lower eyelid.However,further studies are required to determine the proper mode and energy to be used for the procedure.

Fig.2. Power distribution between the electrodes in the BodyTite system(Invasix Ltd., Yokneam, Israel).36

Fig.3. Heating patterns of various RF delivery devices (Courtesy of Lutronic,Billerica, MA).9 PIH, post-inflammatory hyperpigmentation.

6.Fractional radiofrequency microneedling

RF devices use an electric current to create a thermal effect that results in collagen contraction and neocollagenesis,cell apoptosis,and fatty tissue reduction.35The AGNESTM microinsulated needles with RF applicators (Gowoonsesang Cosmetics Co., Seongnam, Gyeonggi, Korea)have been used to treat lower eyelid fat bulges without causing serious adverse effects.The needles are composed of two parts: a proximal insulated area and a distal noninsulated area.Proximal insulation protects the epidermis against thermal damage,allowing the procedure to be non-ablative and minimally invasive.38Moreover,it has shouldered that function as a stop and allow the operator to insert the needle to a consistent depth to avoid deep tissue injuries(Fig.4).This fractional RF microneedle device allows the operator to control the depth and intensity of thermal lesions,thus delivering focused RF energy without epidermal damage using insulated needles.Two types of needle tips were used sequentially in each session:a tip with three short needles measuring 1.5 mm in length with a proximal insulation of 0.3 mm(Fig.4A),and another tip with a single long needle measuring 5 mm in length with proximal insulation of 2.5 mm(Fig.4C).The periorbital area was first treated with short needles (exposure time: 150 ms; power: 9 W) to tighten the overlying dermis(Fig.4B).The fat pocket was then treated with a long needle(exposure time: 400 ms; power: 9 W) to tighten the orbital septum and damage the fat cells directly (Fig.4D).As a result, the extent of fat bulging and the investigator’s global assessment scale scores decreased.

The needle RF system has advantages over other conventional fractional RF systems.First, the system has two types of tips with different needle lengths to reduce the fat volume and tighten the overlying connective tissues.In particular,the 5-mm long needle can effectively target orbital fat,induce its destruction,and tighten the orbital septum.Second,the small and simple needles can be used to precisely target the curved periorbital surface and treat infraorbital fat bulging more effectively.However,some risks are associated with the use of a 5-mm needle.Aside from the risk of bleeding,8there is a possibility of eyeball injury.To avoid this complication,the operator can use the second to fourth fingers of the non-dominant hand to protect the eyeball during the procedure(Fig.4).

Fig.4. Two types of needle tips in the AGNES™system and the treated area in a representative patient.(A)A tip with three short needles measuring 1.5 mm in length with 0.3 mm of proximal insulation is shown in panel.(B)Areas treated with the three short needles are shown in panel.(C)A tip with a single long needle measuring 5 mm in length with 2.5 mm of insulation proximally is shown in panel.(D) Areas treated with the single long needle are shown in panel.

7.AdipoLASER rejuvenation

ALJ involves a variety of minimally invasive lasers and lipolysis-based techniques.The present study assessed the impact of this ALJ approach.Fractional CO2laser has a photodestructive or high-level laser therapy(HLLT) effect and a low-level laser therapy (LLLT) component in the beam’s periphery.The LLLT effect may prolong life and improve the survival of fat grafts, with the well-documented HLLT effect inducing swift collagenesis and better remodeling of the dermal matrix.Patients underwent laser-assisted lipolysis of the jawline and submental area with lipoaspiration and fat grafting for the malar and periorbital zones, in addition to whole-face fractional CO2laser resurfacing.Standard microliposuction and laser-assisted lipolysis are reductive techniques,whereas autologous fat grafting and fractional CO2laser rejuvenation are regenerative techniques.

Laser-assisted lipolysis is generally performed under orotracheal intubation anesthesia in addition to intravenous sedation and local anesthesia.In a study by Jianu et al.,39the patients were monitored for 1–18 months postoperatively.Compared with baseline findings, significant improvements were noted regarding fat distribution,skin condition,and contour correction in all patients treated with this technique.The overall satisfaction rates were excellent (63.2%), good (30.8%), fair(4.2%), and poor (1.8%) compared with the control group: poor, 6.8%;fair,53.3%;good,27.1%;and excellent,12.9%.Swelling was observed in 90%of the patients,which most often disappeared by 10 days,and local ecchymosis was experienced in 40% of the patients, which resolved spontaneously after 1 week.Improvement in exfoliation and healing periods was observed if platelet-rich plasma was used concomitantly after fractional CO2treatment (from 5–6 days to 7–9 days).Therefore,the fractional ablative approach may have acted as a drug delivery system.Fractional ablative CO2treatment improves skin texture and tightness, and exhibits a photobioactivation reaction, as with LAL, in the periphery of the lipolysis area.This method achieves LLLT and HLLT simultaneously.However, no reports have discussed the use of this technique in the lower eyelid, which would be an interesting research topic.

8.Conclusion

In recent years,our department has had rich experience in performing eye rejuvenation.We found that it is difficult to achieve good results of photoelectric treatment considering issues in aging, such as fine lines,slight ptosis, and dark circles.Since it is minimally invasive and has a short downtime,traditional surgical treatment of orbital fat swelling has been replaced by Q-switched laser lipolysis.These photoelectric methods enrich eye rejuvenation techniques and provide patients with more treatment choices.

Although, there are still problems associated with photoelectric therapy, such as worsening of melanin deposition after RF treatment of fine lines or inaccurate localization of bulging fat by Q-switched laser.However, with continuous advancements in technology, photoelectric therapy may develop further, thus addressing these limitations.Additionally,the combination of different photoelectric methods with surgery will promote developments in eye rejuvenation.

Ethics declarations

Ethics approval and consent to participate

Not applicable.

Competing interests

The authors declare that they have no competing interests.

Authors’contributions

Cheng LY:Conceptualization,Methodology,Software.Cheng LY and Zhang L: Data curation, Writing-Original draft.Sun XM and Zhang LC:Visualization, Investigation.Mao XY: Software, Validation.Zhang YG and Zhang Y: Writing-Reviewing and Editing.Zhang Y:Supervision.

Acknowledgments

This study was supported by the Shanghai Municipal Key Clinical Specialty Project(grant no.shslczdzk00901).