Highlight
- Periocular low-level light therapy (LLLT) administered before and after cataract surgery significantly alleviates dry eye symptoms, a common postoperative complication.
- LLLT enhances tear film stability and reduces tear osmolarity, critical parameters in maintaining ocular surface health post-surgery.
- The treatment preserves corneal epithelial integrity, as demonstrated by stable corneal fluorescein staining scores, and is free from adverse effects.
- LLLT’s noninvasive, operator-independent application makes it a promising adjunct to routine perioperative care after cataract surgery.
Study Background and Disease Burden
Cataract surgery is among the most frequently performed surgical procedures worldwide, with a generally excellent safety profile and rapid visual recovery. However, dry eye disease (DED) is recognized as a prevalent and bothersome complication following cataract surgery, often manifesting as ocular discomfort, tearing, blurred vision, and foreign body sensation. Postoperative dry eye stems from surgical trauma to the ocular surface, disruption of the tear film, corneal nerve damage, and perioperative medication use. The burden of postoperative dry eye extends beyond patient discomfort; it can impair visual quality, reduce patient satisfaction, and delay rehabilitation.
Conventional management of post-cataract surgery dry eye primarily involves symptomatic treatment with artificial tears and anti-inflammatory agents. There remains a clinical need for effective, preventive interventions that target underlying pathophysiological mechanisms while minimizing burdens and side effects.
Low-level light therapy (LLLT), a treatment modality utilizing specific wavelengths of light to modulate cellular function and promote tissue repair, has emerged as a novel intervention in several ophthalmic and dermatologic conditions. Prior studies suggest LLLT may enhance mitochondrial activity, reduce inflammation, and improve tissue homeostasis. Its potential to prevent or mitigate postoperative dry eye remains under active investigation.
Study Design
A prospective, double-masked, randomized controlled clinical trial evaluated the efficacy and safety of periocular LLLT in preventing dry eye following cataract surgery. The trial enrolled 89 patients (45 men, mean age 73.75 years) scheduled for elective cataract surgery. Exclusion criteria were prior ocular surface disease, dry eye diagnosis, history of ocular surgery, or presence of ocular comorbidities.
Participants were randomized to receive either:
- LLLT using a specialized device delivering light at 633 ± 10 nm wavelength, applied periocularly for seven days before and seven days after the surgery;
- Sham treatment mimicking all aspects of LLLT except that the light intensity was insufficient to elicit a therapeutic effect.
Key endpoints included:
- Symptoms of dry eye, assessed by the Ocular Surface Disease Index (OSDI) questionnaire;
- Tear film stability;
- Tear production, measured via Schirmer type 1 test;
- Tear osmolarity;
- Corneal epithelial damage, assessed through corneal fluorescein staining.
All parameters were evaluated at baseline (preoperative), 1 week, and 1 month following surgery.
Key Findings
Patients undergoing LLLT demonstrated significant symptomatic and objective improvements compared with sham controls.
- Dry Eye Symptoms: Mean OSDI scores improved markedly in the LLLT group from a baseline of 26.62 to 15.53 at 1 week and further to 13.36 at 1 month postoperatively (P < .001). In contrast, the sham group experienced a worsening of OSDI scores post-surgery.
- Tear Film Stability: Tear film breakup time increased significantly in the LLLT cohort, indicating enhanced tear film stability postoperatively, whereas the sham group saw no improvement.
- Tear Osmolarity: A key pathogenic marker in DED, tear osmolarity decreased significantly in the LLLT group following surgery, while it increased in the sham group, reflecting worsening ocular surface homeostasis.
- Corneal Epithelium Integrity: Corneal fluorescein staining scores remained stable throughout follow-up in the LLLT group, indicating preservation of corneal epithelial integrity. Patients in the sham group exhibited a significant increase in staining scores, indicating epithelial damage related to surgery.
- Adverse Effects: No adverse events or complications attributable to LLLT were reported, underscoring its safety in this clinical setting.
These findings collectively suggest that perioperative LLLT not only alleviates subjective symptoms but also positively modulates mechanisms critical to ocular surface health after cataract surgery.
Expert Commentary
The trial’s double-masked randomized design bolsters the robustness of its conclusions regarding LLLT efficacy in preventing post-cataract surgery dry eye. The exclusion of patients with preexisting ocular surface disease enables clearer assessment of LLLT’s preventive potential.
The biological plausibility of LLLT’s benefits may relate to its ability to stimulate mitochondrial cytochrome c oxidase activity, enhancing ATP production, promoting cellular repair processes, and exerting anti-inflammatory effects on periocular tissues. These mechanisms are consistent with observed improvements in tear film stability and preservation of epithelial integrity.
Limitations include the study’s sample size, which, while adequate to demonstrate significant effects, warrants validation in larger multicenter trials with longer follow-up to assess durability. Additionally, the study population was elderly, reflecting typical cataract surgery demographics; generalizability to younger or more diverse populations merits investigation.
Current clinical guidelines for cataract surgery have yet to incorporate LLLT as a standard perioperative intervention. However, these promising results provide a compelling rationale for its integration, especially given the therapy’s noninvasive nature and minimal patient burden.
Conclusion
Periocular low-level light therapy administered before and after cataract surgery effectively prevents postoperative dry eye symptoms and preserves tear film and corneal epithelial health. Its favorable safety profile and ease of application support its potential as a routine adjunct in cataract surgery perioperative management to enhance patient comfort and satisfaction.
Future research should aim to confirm these findings across broader patient populations, optimize treatment parameters, and explore mechanistic pathways in greater detail. Incorporating LLLT into clinical protocols may represent an important advance in addressing the unmet clinical need of post-cataract surgery dry eye.
References
Timofte-Zorila MM, Lixi F, Vlas N, Troisi M, Özkan G, Pavel-Tanasa M, Istrate S, Preda C, Coco G, Namazbayeva A, Giannaccare G, Branisteanu DC. Effect of Low-Level Light Therapy on Ocular Surface Parameters in Patients Undergoing Cataract Surgery: A Prospective Double-Masked Randomized Controlled Clinical Trial. Ophthalmol Ther. 2025 Aug 24. doi: 10.1007/s40123-025-01228-6.
Additional relevant literature:
1. Lemp MA. Advances in understanding and managing dry eye disease. Am J Ophthalmol. 2008 May;145(3):350-356.
2. Hamblin MR. Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS Biophys. 2017;4(3):337-361.
3. Li F, Chen H, Ni N, et al. The role of tear osmolarity in dry eye disease and its clinical applications. Ocul Surf. 2021;19:88-95.