Intense pulsed light(脈衝光) 治療乾眼症潛力

Treating dry eye with intense pulsed light April 19, 2015     By Michelle Dalton San Diego—Patients with evaporative dry eye produce an abnormal meibum that is more viscous than patients with normal meibum, said Gargi K. Vora, MD.Severe inflammation and bacterial overgrowth can exacerbate the problem, added Dr. Vora, who is in practice in Durham, NC.Anti-inflammatory drops, warm compresses, and even lid expression have been marginally effective, but intense pulsed light (IPL) may be a viable option. Dr. Vora conducted a retrospective chart review of 100 patients with a diagnosis of meibomian gland dysfunction (MGD) and dry eye syndrome that underwent IPL therapy from September 2012 to August 2014 at two outpatient eye centers (one at Duke and one at a private practice in Pennsylvania and New Jersey).IPL has been used in dermatology practices as a rosacea treatment for years, but "is a relatively new treatment for MGD and evaporative dry eye," she said, although it has been used for inflammatory lid disease.Some studies by Toyos et al. have hyptothesized that IPL treatment near the lid would cause the abnormal blood vessels to close and noted the effect seemed to be positive on patients with MGD. (Rolando Toyos, MD, is credited as far back as 2002 with discovering the potential use of IPL in ocular indications.)Dr. Vora's group evaluated numerous dry eye parameters, including the ocular surface disease index (OSDI), tear break-up time (TBUT), eyelid and facial vascularity, eyelid margin edema, and meibomian gland oil flow and quality. They used the Dermamed Quadra 4 IPL with its proprietary dry eye mode, and used Fitzpatrick scale to determine the energy parameters, Dr. Vora said.The laser uses a xenon flashlight in a band between 400 and 1,300 nm."We used from 10 to 15 treatment spots on each side of the face," she added.The average age was 61 years and 71% were female. On average, patients underwent 4 IPL sessions (range 3-6), and titrating the treatment was allowed. Additional treatments have been shown in other studies to thin the meibomian secretions. From pre-treatment to final visit after IPL treatments, there was a statistically significant decrease in scoring of lid edema, facial telangiectasia, lid vascularity, meibiomian gland severity score, and OSDI score (-9.6 in symptom scores, which was a statistically significant improvement).There was also statistically significant increase in oil flow and TBUT. There were no significant changes in IOP or visual acuity."We don't know the exact mechanism of action of the IPL on MGD or dry eye, but we do believe the localized thermal effect causes melting of meibum and a reduction of bacterial/parasitic growth," she said.Dr. Vora elaborated on the treatment protocol, by noting the treatment schedule was clinician-derived. So, while patients could be seen anywhere from 4 to 6 weeks after the initial treatment, all data outcomes evaluated last visit compared with baseline, she said.Further, all patients in the study were allowed to continue lid hygiene, but were not allowed any other additional treatment, she said.