Dry eye disease (DED) is a frequent ocular surface disease (OSD) of multifactorial origin, characterised by disruption of tear film homeostasis and associated with ocular discomfort and/or visual disturbance. Cataract surgery, which is one of the most often performed interventions worldwide, can induce or worsen the symptoms of DED. Despite lack of guidelines on DED prophylaxis before cataract surgery in the general population, there is a growing interest in this topic due to the high prevalence of postoperative DED. A recent randomised controlled trial (RCT) with one month follow-up showed that prophylactic low-level light therapy (LLLT) before and after cataract surgery in patients without pre-existing DED significantly improved postoperative tear film stability, as well as reduced ocular discomfort, compared to no prophylaxis. Apart from LLLT, another light-based treatment for DED is intense pulsed light (IPL); the treatments have shown favourable outcomes in the management of DED, both as stand-alone choices or in combination.

Dry eye disease (DED) is a frequent ocular surface disease (OSD) of multifactorial origin, characterised by disruption of tear film homeostasis and associated with ocular discomfort and/or visual disturbance. Cataract surgery, which is one of the most often performed interventions worldwide, can induce or worsen the symptoms of DED. Despite lack of guidelines on DED prophylaxis before cataract surgery in the general population, there is a growing interest in this topic due to the high prevalence of postoperative DED. A recent randomised controlled trial (RCT) with one month follow-up showed that prophylactic low-level light therapy (LLLT) before and after cataract surgery in patients without pre-existing DED significantly improved postoperative tear film stability, as well as reduced ocular discomfort, compared to no prophylaxis. Apart from LLLT, another light-based treatment for DED is intense pulsed light (IPL); the treatments have shown favourable outcomes in the management of DED, both as stand-alone choices or in combination.

There is currently no comparative data available which would allow to choose between LLLT and IPL as prophylaxis for iatrogenic DED after cataract surgery.

The primary objective of this RCT is to compare LLLT versus IPL as prophylaxis for iatrogenic DED after cataract surgery in terms of patient-reported symptoms of eye dryness at 3 months.

Inclusion Criteria:

• aged ≥50 years
• scheduled for bilateral cataract surgery by phacoemulsification
• without current DED treatment, including eye drops, for at least two months before the inclusion
• with preoperative OSDI ≤22 points, indicating absence of DED or mild DED
• who signed the informed consent and are willing to comply with the protocol requirements based on the investigator's judgment
• affiliated with a social security scheme
• with an ability to answer questionnaires and to communicate freely in French.

Exclusion Criteria:

• set to undergo implantation of a multifocal intraocular lens
• using contact lenses
• with any of the following in the included eye: (i) age-related macular degeneration (AMD), (ii) previous ocular surgery, (iii) abnormal clinical exam of the ocular surface or (iv) undergoing any ocular treatment
• with systemic contraindications, including autoimmune diseases (e.g., Sjögren syndrome)
• with general contraindications for LLLT or IPL treatment: dark pigmented skin (Fitzpatrick grade ≥5), skin photosensitivity (regardless if innate, pathological or medically-induced), or neurological light sensitivity (e.g. epilepsy, light-induced migraines)
• with contraindications for LLLT or IPL treatment limited to the treatment area: history of skin cancer, skin pigmented lesions, as well as fixed/permanent skin piercings, face tattoos, semi-permanent make-up (including microblading) or skin defects
• with any concomitant disease or disorder which, in the opinion of the investigator, may put the patient at risk or may influence the result of the study
• with protected status under articles L1121-6, LL121-8 and L1122-2 of the French Public Health Code
• who cannot comply with the protocol requirements based on the investigator's judgment.

Surgeons and the medical staff (the evaluators) that administer the questionnaires will be blinded to the randomisation, but the orthoptists performing the treatment will be aware of the randomisation. Participants will not be informed of their allocated treatment; however, they may guess which treatment they received as the IPL and LLLT devices look differently, and the patient can see the device being used. Moreover, the patient's experience will be different. In the IPL group, light is administered in pulses and the patients experience heat; furthermore, cooling ultrasound gel and eye patches are used for protection. In the LLLT group, light is administered continuously, and there is no protective gel nor eye patches. At the end of the study, participants may request what type of treatment they received.