**8. Adverse events and advantages**

There were no adverse effects with the IPL. Nevertheless, the relationship between Intense Pulsed Light (IPL) and Meibomian Gland Expression (MGX), or Warm Compresses (WC) and MGX, on the one hand, and MGX on the other hand, maybe non-linear and complex. Since IPL can be expensive in some clinics, it's essential to know if persistent eyelid warmth at home accompanied by WC/MGX can produce comparable results as IPL/MGX. However, Broadband Light (BBL) technology has the potential to cause damage. Just transient side changes were reported, such as hyperpigmentation, eyelash thinning, and slight conjunctival abrasion. The lid thinning has been seen by using higher settings than those prescribed in this report, and the suspected abrasion was most likely caused by slight damage caused by the corneal shields in the close eyelids' environment, rather than the BBL therapy itself. Other warnings that can help to reduce the low risk of transient lash thinning include scraping any gel that may couple with the light from the lashes and wrapping a metallic wrap around the edges of the cylinder to keep the treatment confined to the 7 mm circular adaptor's treatment area. To prevent any long-term risks, proper procedure and the use of correctly mounted, well-polished metallic eye shields are critical for corneal protection. It's important to remember that systems vary, and configurations can be tailored to the equipment in use and specific patient characteristics (skin texture, sun sensitivity, light-sensitizing drugs, and so on), with a thorough knowledge of the tissue effects at different settings/ parameters [1].

### **8.1 IPL care has a risk vs. benefit ratio**

Gupta et al. proved that IPL therapy for evaporative DED is a safe treatment in a study [47].

IPL appears to be a reliable and successful therapy for patients with evaporative DED, based on changes in quantitative clinical test results and subjective OSDI scoring evidence. The oil flow score and TBUT all increased significantly. There were no significant differences in intraocular pressure or acuity. There were no reports of ocular side effects. Some research found no adverse effects following IPL therapy and a substantial increase in MGD symptoms. In Chinese MGD cases with darker skin types (Fitzpatrick skin types III-IV), IPL treatment has also been effective and safe. Rong et al. found that strong pulsed light directly exposed to the eyelids, together with meibomian gland expression, effectively treats MGD [48].

IPL, in combination with MGX, was a safe and successful treatment for MGD. However, we must remember that the light beam emitted will be directed on a particular region, selectively damaging specific targets in the area being treated (e.g., capillaries, brown spots, or tattoo color in the skin), causing them to be eliminated or the region to be replaced with new cells—depending on the preferred procedure. IPL's effects can also be unwelcome, resulting in dangers like burns, blistering, and discomfort. Keloids and skin pigmentation are common severe symptoms. As a result, before proceeding with the procedure, the practitioner should advise the worried patients about the risks and benefits of IPL therapy. In meibomian gland dysfunction, intensive pulsed light therapy affects tear proteins, lipids, and inflammatory markers by controlling the amounts of total lipids, cholesterol, triglycerides, and phospholipids in the tear; IPL helps to alleviate the symptoms of DED. After IPL treatment, Ahmed et al. found substantial differences in tear protein concentrations and molecular weight [49]. The molecular weights of tear lysozyme, albumin, and lactoferrin were the most affected. The tears of MGD patients had

slightly smaller levels of anionic phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol on thin-layer chromatography, however typical levels of zwitterionic neutral phospholipid phosphatidylcholine. After IPL treatment, these anionic phospholipids demonstrated impressive improvement. IPL enhances tear protein and lipid content and structure. Several studies have found IPL therapy reduces interleukin-6, interleukin-17A, and prostaglandin E2 levels in DED patients' tear fluid. Furthermore, they stated that a reduction in these inflammatory factors was related to decreased signs and symptoms. These decreases in inflammatory factors were linked to increases in corneal staining ratings, indicating that ocular surface epithelial damage had improved. According to some reports, changes in IL-6, IL-17A, and IL-1 levels were lowest one week after IPL, which was earlier than the appearance of clinical result peaks at one month. This means that increases in tear cytokine levels could be more sensitive indicators of IPL symptoms than clinical signs. IPL has an impact on the MGD meibum.

IPL has been shown in several trials to help release clogged meibum by thermal pulsation treatment. MGD is a critical contributor to dry eye illness with Sjogren disease, according to Godin et al. study's and should not be underestimated when evaluating care choices [50].

The meibum was able to clear its clogged ducts with the aid of thermal pulsation. Thermal pulsation is a treatment choice for patients with Sjogren's disease who have dry eye and MGD symptoms, and it will increase meibum consistency directly. Another research by yin et al. found that after therapy, TBUT, OSDI, MG expressibility, meibum quality, and MG dropout increased. IPL therapy significantly increased MG microstructure indices such as meibum, MG Acinar Unit Density (AUD), MG Acinar Longest Diameter (ALD), and the positive rate of Inflammatory Cells (ICs) across glandular structures. These results indicate that IPL therapy helps DED patients with MGD symptoms. It also increases eyelid hygiene and related ocular-surface indices, MG function, and MG macrostructure. Moreover, in MGD cases, IPL therapy primarily enhanced MG microstructure and reduces MG inflammation. MGD causes a difference in meibum content and quantity, which contributes to evaporative dry eye and ocular surface damage, increasing dry eye symptoms in certain people, according to Chhadva et al. on the meibum of MGD patients [51]. These modifications can be systemically managed with IPL, reducing the patient's difficulty [23, 31].

#### **8.2 The advantages of IPL**

Sufferers with refractory meibomian gland dysfunction are treated with intense pulsed light. Even more, research suggests that using strong pulsed light to treat MGD cases tends to alleviate dry eye symptoms. The aim of Arita et al. research.'s was to see whether strong pulsed light (IPL) combined with meibomian gland expression (MGX) could help with refractory meibomian gland dysfunction (MGD). Her findings indicated that combining IPL and MGX improved tear film homeostasis and alleviated ocular symptoms in cases with refractory MGD, making it a potential treatment option for this disorder. The meibomian gland activity was increased, the tear film was balanced, and ocular surface inflammation was reduced after IPL therapy. Meibum consistency, meibum expressibility, lid margin abnormality, ocular surface staining, tear film breakup period (TBUT), and the Ocular Surface Disease Index (OSDI) all improved significantly after IPL. Low meibum expressibility and a short TBUT were linked to a more significant improvement in the OSDI. Sufferers with refractory obstructive meibomian gland dysfunction responded well to IPL therapy combined with meibomian gland probing. Huang et al. discovered that, in comparison to IPL or Meibomian Gland Probing (MGP) alone, the mixture

*Intense Pulse Laser Therapy and Dry Eye Disease DOI: http://dx.doi.org/10.5772/intechopen.99165*

**Figure 4.** *Comparison of methods of IPL with and without gel.*

MGP-IPL showed the most remarkable results in relieving all symptoms and signs and assisting patients in achieving long-term symptom relief [21, 52].
