Effects of Photobiomodulation Therapy on Patients with Primary Open Angle Glaucoma: A Pilot Study.

OBJECTIVE: The purpose of this work was to study the safety of photobiomodulation therapy in patients with primary open angle glaucoma (POAG). BACKGROUND DATA: Therapeutic options for POAG focus on lowering the intraocular pressure (IOP) but cannot stop disease progression to irreversible damages. METHODS: The study was designed as a controlled, single-blinded, interventional case series (38 patients; 63 eyes). Low-level laser therapy was performed once or twice per week using a continuous wave (CW) diode laser (780 nm; 10 mW; 292 Hz modulation; 3 mm(2) beam spot). The limbus area was circularly irradiated for 30 sec (0.3 W/cm(2); 10 J/cm(2)) at a 1 cm distance. Additional parts of the bulbus were irradiated for 90 sec (30 J/cm(2)) pointing the beam toward retinal areas corresponding to defective visual fields. A control group of 10 patients (20 eyes) received mock treatment. Visual acuity was assessed using Snellen projection optotypes. IOP was determined by applanation tonometry. Visual fields were determined by kinetic Goldmann perimetry. Multifocal visual evoked potential (M-VEP) was recorded in 15 patients (30 eyes). RESULTS: Poor visual acuity (≤ 20/25), initially found in 24 of 63 eyes (38.1%), improved in 17 (70.8%) eyes and did not change in 7 eyes (29.2%). Mean IOP dropped from 24.9 ± 14.9 to 15.0 ± 6.5 mm Hg (-39.7%, p < 0.001). Visual fields were either fully restored, improved by at least 10 degrees, or remained unchanged in 32, 29, and 2 of 63 eyes (51%, 46%, and 3%), respectively. Mean M-VEP latency was reduced by 13.5 msec (-8%, p < 0.001); mean amplitude increased by +677 nV (+14%, p < 0.001). Adverse effects were not observed. No changes were noted in control eyes. CONCLUSIONS: This first small series of cases indicated that photobiomodulation might be a safe approach to lower IOP and to improve visual acuity and fields in eyes with POAG.

Low-level laser therapy improves vision in a patient with retinitis pigmentosa.

OBJECTIVE: This case report describes the effects of low-level laser therapy (LLLT) in a single patient with retinitis pigmentosa (RP). BACKGROUND DATA: RP is a heritable disorder of the retina, which eventually leads to blindness. No therapy is currently available. METHODS: LLLT was applied using a continuous wave laser diode (780 nm, 10 mW average output at 292 Hz, 50% pulse modulation). The complete retina of eyes was irradiated through the conjunctiva for 40 sec (0.4 J, 0.333 W/cm2) two times per week for 2 weeks (1.6 J). A 55-year-old male patient with advanced RP was treated and followed for 7 years. RESULTS: The patient had complained of nyctalopia and decreasing vision. At first presentation, best visual acuity was 20/50 in each eye. Visual fields were reduced to a central residual of 5 degrees. Tritan-dyschromatopsy was found. Retinal potential was absent in electroretinography. Biomicroscopy showed optic nerve atrophy, and narrow retinal vessels with a typical pattern of retinal pigmentation. After four initial treatments of LLLT, visual acuity increased to 20/20 in each eye. Visual fields normalized except for a mid-peripheral absolute concentric scotoma. Five years after discontinuation of LLLT, a relapse was observed. LLLT was repeated (another four treatments) and restored the initial success. During the next 2 years, 17 additional treatments were performed on an "as needed" basis, to maintain the result. CONCLUSIONS: LLLT was shown to improve and maintain vision in a patient with RP, and may thereby have contributed to slowing down blindness.

Low-level laser therapy improves visual acuity in adolescent and adult patients with amblyopia.

OBJECTIVE: The purpose of this study was to examine the effects of low-level laser therapy (LLLT) on visual acuity in adolescent and adult patients with amblyopia. BACKGROUND DATA: Currently, amblyopia can be treated successfully only in children. METHODS: In this single-blinded, placebo-controlled study, 178 patients (mean age 46.8 years) with amblyopia caused by ametropia (110 eyes) or strabismus (121 eyes) were included. For LLLT, the area of the macula was irradiated through the conjunctiva from 1 cm distance for 30 sec with laser light (780 nm, 292 Hz, 1:1 duty cycle; average power 7.5 mW; spot area 3 mm(2)). The treatment was repeated on average 3.5 times, resulting in a mean total dose of 0.77 J/cm(2). No occlusion was applied, and no additional medication was administered. Best corrected distant visual acuity was determined using Snellen projection optotypes. In 12 patients (12 eyes), the multifocal visual evoked potential (M-VEP) was recorded. A control group of 20 patients (20 eyes) received mock treatment. RESULTS: Visual acuity improved in ∼90% of the eyes treated with LLLT (p<0.001), increasing by three or more lines in 56.2% and 53.6% of the eyes with amblyopia caused by ametropia and strabismus, respectively. The treatment effect was maintained for at least 6 months. The mean M-VEP amplitude increased by 1207 nV (p<0.001) and mean latency was reduced by 7 msec (p=0.14). No changes were noted in the control group. CONCLUSIONS: LLLT led to a significant improvement in visual acuity in adolescent and adult patients with amblyopia caused by ametropia or strabismus.

Early diagnosis of ocular hypertension using a low-intensity laser irradiation test.

OBJECTIVE: We investigated the potential use of low-intensity laser irradiation (LILI) as a diagnostic tool for identifying hypertensive eyes at risk of glaucoma. BACKGROUND DATA: The diagnosis of early-stage ocular hypertension is particularly difficult to establish. METHODS: This study of a case series included 123 healthy subjects with normal vision. The intraocular pressure (IOP) was determined before (baseline) and 30 min after a 30-sec irradiation of the limbus area with laser light (780 nm; 7.5 mW; 292 Hz modulation). RESULTS: Baseline IOP was >21 mm Hg in 44 of 211 eyes (20.9%), consistent with ocular hypertension. LILI decreased the mean IOP by 6.2 mm Hg (-25.7%; p < 0.001; paired t test) in these eyes. The remaining 167 eyes (79.1%) exhibited a normotensive IOP

Low-level laser therapy improves vision in patients with age-related macular degeneration.

OBJECTIVE: The objective of this study of a case series was to examine the effects of low-level laser therapy (LLLT) in patients with age-related macular degeneration (AMD). BACKGROUND DATA: AMD affects a large proportion of the elderly population; current therapeutic options for AMD are limited, however. PATIENTS AND METHODS: In total, 203 patients (90 men and 113 women; mean age 63.4 +/- 5.3 y) with beginning ("dry") or advanced ("wet") forms of AMD (n = 348 eyes) were included in the study. One hundred ninety-three patients (mean age 64.6 +/- 4.3 y; n = 328 eyes) with cataracts (n = 182 eyes) or without cataracts (n = 146 eyes) were treated using LLLT four times (twice per week). A semiconductor laser diode (780 nm, 7.5 mW, 292 Hz, continuous emission) was used for transconjunctival irradiation of the macula for 40 sec (0.3 J/cm2) resulting in a total dose of 1.2 J/cm2. Ten patients (n = 20 eyes) with AMD received mock treatment and served as controls. Visual acuity was measured at each visit. Data were analyzed retrospectively using a t-test. RESULTS: LLLT significantly improved visual acuity (p < 0.00001 versus baseline) in 162/182 (95%) of eyes with cataracts and 142/146 (97%) of eyes without cataracts. The prevalence of metamorphopsia, scotoma, and dyschromatopsia was reduced. In patients with wet AMD, edema and bleeding improved. The improved vision was maintained for 3-36 mo after treatment. Visual acuity in the control group remained unchanged. No adverse effects were observed in those undergoing therapy. CONCLUSION: In patients with AMD, LLLT significantly improved visual acuity without adverse side effects and may thus help to prevent loss of vision.