Laser Pointer-Induced Maculopathy: More Than Meets the Eye

The blue light hazard and its use on the evaluation of photochemical risk for domestic lighting. An in vivo study

BACKGROUND

Nowadays artificial light highly increases human exposure to light leading to circadian rhythm and sleep perturbations. Moreover, excessive exposure of ocular structures to photons can induce irreversible retinal damage. Meta-analyses showed that sunlight exposure influences the age of onset and the progression of Age-related macular degeneration (AMD), the leading cause of blindness in people over fifty-year old. Currently, the blue-light hazard (BLH) curve is used in the evaluation of the phototoxicity of a light source for domestic lighting regulations.

OBJECTIVES

Here, we analyze the phototoxicity threshold in rats and investigate the role played by the light spectrum, assessing the relevance of the use of the BLH-weighting to define phototoxicity.

METHODS

We exposed albino rats to increasing doses of blue and white light, or to lights of different colors to evaluate the impact of each component of the white light spectrum on phototoxicity. Cellular mechanisms of cell death and cellular stress induced by light were analyzed.

RESULTS

Our results show that the phototoxicity threshold currently accepted for rats is overestimated by a factor of 50 when considering blue light and by a factor of 550 concerning white light. This is the result of the toxicity induced by green light that increases white light toxicity by promoting an inflammatory response. The content of green in white light induces 8 fold more invasion of macrophages in the retina than the content of blue light. Moreover, the use of BLH-weighting does not evaluate the amount of red radiations contained in white light that mitigates damage by inhibiting the nuclear translocation of L-DNase II and reducing by 33% the number of TUNEL-positive cells.

DISCUSSION

These findings question the current methods to determine the phototoxicity of a light source and show the necessity to take into account the entire emission spectrum. As current human phototoxicity thresholds were estimated with the same methods used for rats, our results suggest that they might need to be reconsidered.

An outbreak of subhyaloid hemorrhage after accidental laser exposure during an Indian festival

PURPOSE

To report the clinical manifestations and outcomes of patients who experienced retinal damage due to accidental laser exposure during a festival in Kolhapur, Maharashtra.

METHODS

Consecutive patients who presented with sudden loss of vision following exposure to laser lights during a religious Indian festival (Ganapati festival) on the same day (9 September 2022) at the same location (idol visarjan procession) were identified from the medical records of various eye hospitals in Kolhapur district of Maharashtra. Eyes with persistent subhyaloid hemorrhage (SHH) were taken up for neodymium-doped yttrium aluminum garnet (Nd: YAG) posterior hyaloidotomy. Patients were examined at weekly intervals up to 1 month.

RESULTS

Thirty-four eyes of 34 men were identified with age ranging from 18 to 27 years. The mean duration of exposure to the laser projections was 4.9 ± 1.7 h, and the mean distance from the laser source was 7.3 ± 2.7 feet. All presented with SHH involving the macula. SHH had a median size of 3 disc diameters or larger in 30 eyes (88%), and 29 (97%) of these required hyaloidotomy while one patient underwent pars plana vitrectomy. The mean visual acuity improved from 1.45 ± 0.5 log of minimum angle of resolution (logMAR; 20/560 Snellen) to 0.11 ± 0.19 logMAR (20/25 Snellen) (P < 0.001). One eye showed full-thickness macular hole with visual acuity of 20/200.

CONCLUSION

We report a large number of patients experiencing laser-induced SHH, resembling an outbreak, due to exposure to a malfunctioning high-powered recreational laser during a religious festival.

Effect of red-light therapy on retinal and choroidal blood perfusion in myopic children

OBJECTIVE

To investigate the effect of repeated low-level red-light therapy (RLRLT) on retinal and choroidal blood perfusion in myopic children.

METHODS

Forty-seven myopic children (mean spherical equivalent refractive error [SE]: -2.31 ± 1.26 D; age range: 8.0-11.0 years) were enrolled and received RLRLT (power 2 mW, wavelength 650 nm) for 3 min twice a day, while 20 myopic children (SE: -2.75 ± 0.84 D; age range: 7.0-10.0 years) were included as a control group. All participants wore single-vision distance glasses. Refractive error, axial length (AL) and other biometric parameters were measured at baseline and during follow-up visits in the first, second and fourth weeks after initiation of treatment. Retinal thickness, subfoveal choroidal thickness (SFCT), total choroidal area (TCA), luminal area (LA), stromal area (SA) and choroidal vascularity index (CVI) were obtained using optical coherence tomography (OCT). The percentage retinal vascular density (VD%) and choriocapillaris flow voids (FV%) were measured using en-face OCT angiography.

RESULTS

After 4 weeks of treatment, a significant increase in SFCT was observed in the RLRLT group, with an average increase of 14.5 μm (95% confidence interval [CI]: 9.6-19.5 μm), compared with a decrease of -1.7 μm (95% CI: -9.1 to 5.7 μm) in the control group (p < 0.0001). However, no significant changes in retinal thickness or VD% were observed in either group (all p > 0.05). In the OCT images from the RLRLT group, no abnormal retinal morphology related to photodamage was observed. The horizontal scans revealed an increase in TCA, LA and CVI over time (all p < 0.05), while SA and FV% remained unchanged (both p > 0.05).

CONCLUSIONS

These findings indicate that RLRLT can enhance choroidal blood perfusion in myopic children, demonstrating a cumulative effect over time.

Case Report: Multimodal, Longitudinal Assessment of Retinal Structure and Function following Laser Retinal Injury

SIGNIFICANCE

This case report demonstrates the use of novel imaging techniques and functional tests to longitudinally evaluate retinal structure and function after laser retinal injury. The structural and functional prognosis could be predicted with clinical findings, high-resolution retinal imaging, and functional testing.

PURPOSE

We present a laser retinal injury case in which an adaptive optics scanning laser ophthalmoscope and adaptive optics-based psychophysics were used to examine and monitor retinal structure and function after accidental exposure to a 1-W infrared laser beam.

CASE REPORT

A 23-year-old patient was unwittingly exposed to a 1-W, 852-nm continuous-wave laser at work as they noticed a small central blurry spot in the right eye. An initial eye examination was done 1 day after exposure, and the right eye's acuity was 20/25 -2 . Posterior segment evaluation revealed disrupted outer retina near the right eye's fovea. Adaptive optics imaging 2 weeks after the exposure revealed a 0.50 × 0.75° elliptical area with irregular borders and abnormal cone reflectivity just below the fovea. Starting at 1-month follow-up, structural recovery was observed on optical coherence tomography (OCT). Subsequent adaptive optics imaging showed significant recovery of cone reflectivity. Importantly, adaptive optics microperimetry showed measurable detection thresholds at all affected retinal locations at 6 months. By 10 months, all sites exhibited normal sensitivities.

CONCLUSIONS

Retinal structure and function from laser injury can be visualized and measured with OCT, adaptive optics imaging, and psychophysics. An intact Bruch's membrane on OCT and measurable retinal sensitivity by adaptive optics microperimetry may serve as good biomarkers for retinal recovery.

Laser-induced choroidal neovascularization: A case report and some reflection on animal models for age-related macular degeneration

RATIONALE

Laser induced maculopathy includes retinal photoreceptor disruption, macular hole, macular hemorrhage, and rarely choroidal neovascularization (CNV). Here we report a case of laser induced CNV that was treated by intravitreal anti-vascular endothelial growth factor (VEGF) injection and resulted in visual improvement and CNV resolution during 1-year follow up. In addition, the case of laser induced CNV treated with intravitreal anti-VEGF injections are reviewed for the first time in literature.

PATIENT CONCERNS

A 7-year-old boy presented to our department with blurred vision in his right eye for 2 months. The symptom immediately happened after the boy staring at the laser beam for a few seconds. Examination of ocular fundus with slit lamp showed yellowish lesion in macula in his right eye.

DIAGNOSES

CNV was confirmed by fundus examinations, including color fundus photograph, spectral domain optical coherence tomography, fluorescein angiography, and spectral domain optical coherence tomography angiography.

INTERVENTIONS

After the diagnosis of laser induced CNV, intravitreal ranibizumab (LUCENTIS, NOVARTIS) injection was performed.

OUTCOMES

After 1 injection of intravitreal ranibizumab, the best corrected visual acuity improved from 20/50 to 30/50 and CNV gradually regressed during 1-year follow up.

LESSONS

For young patients with laser induced CNV, intravitreal anti-VEGF injections may be helpful in visual improvement and CNV regression. Moreover, age seems to be a significant factor thus we propose that old animals may be more appropriate for laser induced CNV animal models of age-related macular degeneration.

Ocular Complications After Laser or Light-Based Therapy-Dangers Dermatologists Should Know

BACKGROUND

Laser and light-based technologies have been used in the medical field for over 50 years. In dermatologic and cosmetic practice, cutaneous side effects are commonly discussed; however, ocular injury may also occur.

OBJECTIVE

To complete a systematic review of the current literature regarding ocular complications in the dermatologic field after laser and/or light-based therapies.

MATERIALS AND METHODS

A systematic review of the Medline database was performed in August 2020 using the search terms "laser or light and ocular and complication." The inclusion criteria were articles written in English discussing ocular complications after laser or light-based therapy for dermatologic or cosmetic indications.

RESULTS

A total of 36 articles were included for review. Carbon dioxide was the most frequently used laser causing ocular damage, and the most common ophthalmologic complication was temporary ectropion. Patients described visual disturbances and pain as the most common symptoms. A large proportion of articles did not report the use of appropriate eye protection at the time of injury.

CONCLUSION

Although ocular injury post-laser or light-based procedures are rare, clinicians must be acutely aware of the signs and symptoms associated with eye damage. The informed consent process should thoroughly describe the possibility of ocular complications post-treatment, and medical practices should have appropriate emergency plans and protective equipment in place to decrease both patient and staff risk of injury.

Internal limiting membrane peeling without vitrectomy for laser-induced macular holes in two children

PURPOSE

To describe a technique of internal limiting membrane (ILM) peeling without vitrectomy for the treatment of laser-induced macular holes in two children.

METHODS

ILM peeling was performed under the vitreous hyaloid, and the vitreous was retained. Slit lamp and optical coherence tomographic examinations were performed before and after surgery.

RESULTS

Macular holes were closed with different patterns at different time in the two patients, while visual acuity improved significantly in both of them eventually.

CONCLUSION

The technique of ILM peeling in the absence of vitrectomy can promote the closure of laser-induced macular holes and minimize the surgical procedure, with few vitrectomy complications in pediatric patients. The closure pattern may vary on account of different injury sources and extents.

Human Fetal Pigmented Ciliary Epithelium Stem Cells have Regenerative Capacity in the Murine Retinal Degeneration Model of Laser Injury

BACKGROUND

Retinal degeneration and related eye disorders have limited treatment interventions. Since stem cell therapy has shown promising results, ciliary epithelium (CE) derived stem cells could be a better choice given the fact that cells from eye niche can better integrate with the degenerating retina, rewiring the synaptic damage.

OBJECTIVE

To test the effect of human fetal pigmented ciliary epithelium-derived neurospheres in the mouse model of laser-induced retinal degeneration.

METHODS

C57 male mice were subjected to retinal injury by Laser photocoagulation. Human fetal pigmented ciliary epithelium was obtained from post-aborted human eyeballs and cultured with epidermal growth factor (rhEGF) and fibroblast growth factor (rhFGF). The six day neurospheres were isolated, dissociated and transplanted into the subretinal space of the laser injured mice at the closest proximity to Laser shots. Mice were analyzed for functional vision through electroretinogram (ERG) and sacrificed at 1 week and 12 week time points. Retinal, Neurotropic, Apoptotic and proliferation markers were analysed using real-time polymerase chain reaction (PCR).

RESULTS

The CE neurospheres showed an increase in the expression of candidate genes analyzed in the study at 1 week time point, which sustained for longer time point of 12 weeks.

CONCLUSION

We showed the efficacy of human CE cells in the regeneration of retinal degeneration in murine model for the first time. CE cells need to be explored comprehensively both in disease and degeneration.

Retinal injury from handheld lasers: a review

Retinal photic injury induced by handheld lasers is a burgeoning public health concern due to the wider accessibility of high-powered devices. Retinal damage from thermal energy can cause potentially severe and permanent vision loss in children and young adults who are particularly vulnerable because of comorbid behavioral, learning, and psychiatric impairments. Understanding the spectrum of specific clinical and imaging features of such laser injuries aids in prompt and accurate diagnosis. Multimodal retinal imaging is important for the identification of the outer retinal abnormalities that characterize this condition. We reviewed 171 reported cases in the English and non-English language literature published from 1999, when handheld laser injury was first described, to December, 2018. Risk factors, demographic and clinical characteristics, as well as multimodal imaging findings, were collected and summarized. These findings both provide insights for public health awareness and guide areas of future investigation.

Cone Photoreceptor Integrity assessed with Adaptive Optics Imaging after Laser-Pointer-Induced Retinal Injury

PURPOSE

To examine the three-dimensional foveal cone photoreceptor structure in a patient who had suffered laser pointer induced retinal injury.

METHODS

Patient underwent standard fundus photography and clinical spectral domain optical coherence tomography (SD-OCT) imaging. High-resolution imaging was performed using an Adaptive Optics-OCT-Scanning Laser Ophthalmoscope (AO-OCT-SLO).

RESULTS

AO imaging revealed loss of inner and outer segments of cone photoreceptors while the anterior retinal layers appeared healthy. Analysis of cone topology showed an increase in Voronoi domain area and a less regular hexagonal packing structure closer to the lesion site.

CONCLUSION

Exposure to laser pointer radiation, however brief, can result in damage to the retina. Here, repeated imaging nine months later showed a decrease in the size of the lesions (ranging from 3.7 to 23.9%) compared to the first time point. However, the longer-term prognosis is likely permanent scarring.

Inner choroidal ischaemia and CNV due to handheld laser-induced maculopathy: a case report and review

There has been a sharp rise of reported handheld laser-induced maculopathy (HLIM) cases over the past decade, a concerning trend that may continue due to unregulated online access to high power lasers. Though HLIM has distinct clinical features, not uncommonly it may masquerade as other retinal disorders. It is critical therefore to recognise the clinical and multimodal imaging characteristics of this important and potentially devastating condition. As HLIM patients are typically young, unique issues need to be considered, such as delayed presentation, difficult history, poor compliance and behavioural or psychiatric comorbidity. This article will review the clinical and diagnostic features of laser injury, with a special emphasis on the multimodal retinal findings. In addition, we present a unique case of HLIM, resembling the presentation of a placoid disease variant and illustrating choroidal ischaemia using advanced retinal imaging, that offers further insight into the mechanisms of laser injury and its complications. The issues addressed in this review aim to increase recognition of an increasingly important and trending condition with potentially profound visual complications.

Improved Diagnosis of Retinal Laser Injuries Using Near-Infrared Autofluorescence

PURPOSE

To assess whether near infrared autofluorescence (NIR-AF) imaging is a useful imaging modality in the diagnosis of handheld laser retinal injuries.

DESIGN

Retrospective observational case series.

METHODS

Twelve patients identified to have handheld laser retinal injuries were included at 2 academic centers. Patients underwent ophthalmic assessment and retinal imaging including fundus photography, optical coherence tomography (OCT), conventional blue autofluorescence (B-AF), and NIR-AF imaging.

RESULTS

In all cases, lesions consistent with retinal laser injury were detected by NIR-AF imaging. The lesions showed a characteristic appearance with central hyperfluorescence and surrounding hypofluorescence, although the number and extent of lesions varied between patients. Findings using other imaging modalities were variable: on color fundus photography these included localized pigmentary changes and on OCT imaging an ellipsoid zone interruption or outer nuclear layer changes. Only subtle changes were evident on B-AF imaging. Other macular conditions, such as poppers retinopathy or solar maculopathy, which may have similar findings on OCT imaging as laser damage, can be differentiated using NIR-AF imaging.

CONCLUSION

An increased incidence of retinal injuries secondary to handheld lasers has been reported in recent years. We show that the diagnosis and full extent of retinal laser injuries is best demonstrated by NIR-AF, as other modalities give variable results. We propose that NIR-AF should be included when investigating patients suspected of macular injury secondary to exposure to handheld lasers.