Retinal Injury Following Laser Pointer Exposure

An Investigation of a Biomimetic Optical System and an Evaluation Model for the Qualitative Analysis of Laser Interference Visual Levels

To objectively quantify the level of visual interference induced by lasers, we developed a biomimetic optical system designed to emulate human vision. This system is based on an optical model of the eye and synthetic imaging principles, allowing it to generate biomimetic optical images that closely mimic human visual perception. Upon exposure to a 532 nm laser, biomimetic optical images were captured under various ambient lighting conditions. By employing a contrast threshold model for human visual target detection and grayscale hierarchy analysis, we devised an evaluation model to quantify the levels of laser-induced visual interference. The bionic images obtained from our experiments, in conjunction with the constructed model, enabled us to assess the degree of laser-induced visual interference. Our results indicate that this system can effectively substitute the human eye when testing laser imaging effects, with the generated bionic images achieving up to 90% concordance with human vision. The proposed evaluation model facilitates the quantitative analysis of laser-induced visual impairment. This apparatus and evaluation model hold significant promise for the precise quantification of laser-induced visual interference levels.

Macular injuries secondary to handheld lasers in a paediatric population-clinical characteristics and indicators of visual impact

BACKGROUND/OBJECTIVES

Aim to identify incidence and prevalence of laser-induced retinal injuries in the Northern Ireland paediatric population and to determine negative clinical and OCT indicators in relation to visual acuity.

SUBJECTS/METHODS

A retrospective analysis was conducted of retinal injuries secondary to handheld laser pens over a 6-year time period with presenting and final visual acuity (VA), laser source and circumstances of the injury recorded. Fundus photographs and OCT images for each case were also collated.

RESULTS

Sixty-five patients (74 eyes) were identified of which 72% were male and mean age was 11.6 years. 40% of patients were symptomatic. Mean presenting VA was 0.16 LogMAR. VA was ≤0.30 LogMAR in 20 eyes (27%) at presentation. Features which impacted VA to a significant level were foveolar location, diffuse morphology, ELM and BM/RPE/IDZ disruption and ORH presence on presenting OCT images. ORHs or ELM disruption resulted in a significant risk ratio of 3.5 (p = 0.002) and 3.4 (p = <0.001) respectively. Mean presenting VA was demonstrated to improve during follow-up from 0.36 to 0.22 LogMAR (n = 20, p = 0.03). When VA was ≤0.30 LogMAR at presentation, mean presenting VA improved from 0.56 to 0.29 LogMAR (p < 0.01) with 58% of eyes improving to a VA of better than 0.30 LogMAR.

CONCLUSIONS

The overall visual loss from macular laser injuries was low and we have identified features on retinal imaging that significantly impact presenting VA. When VA is affected following macular laser injury there is evidence of recovery with >50% of those presenting with VA ≤ 0.30 LogMAR improving to better than 0.30 LogMAR.

Segmentation of laser induced retinal lesions using deep learning (December 2021)

OBJECTIVE

Detection of retinal laser lesions is necessary in both the evaluation of the extent of damage from high power laser sources, and in validating treatments involving the placement of laser lesions. However, such lesions are difficult to detect using Color Fundus cameras alone. Deep learning-based segmentation can remedy this, by highlighting potential lesions in the image.

METHODS

A unique database of images collected at the Air Force Research Laboratory over the past 30 years was used to train deep learning models for classifying images with lesions and for subsequent segmentation. We investigate whether transferring weights from models that learned classification would improve performance of the segmentation models. We use Pearson's correlation coefficient between the initial and final training phases to reveal how the networks are transferring features.

RESULTS

The segmentation models are able to effectively segment a broad range of lesions and imaging conditions.

CONCLUSION

Deep learning-based segmentation of lesions can effectively highlight laser lesions, making this a useful tool for aiding clinicians.

Laser-Induced Maculopathy and Outcomes After Treatment With Corticosteroids and Lutein

This case report presents treatment outcomes for a patient with accidental laser-induced retinal injury. A 30-year-old man was evaluated for a sudden decrease of vision and metamorphopsia in his left eye after staring at a laser in a nightclub five days before presentation. Eye examination showed left visual acuity of 6/18-2 unaided, which improved to 6/12-2 on the pinhole test. Dilated fundoscopy showed a yellow-orange foveolar lesion in the left eye. Optic coherence tomography (OCT) showed an alteration of foveal anatomy predominantly involving the outer retinal layers, hyper-reflective vertical bands, and large cystoid change at the inner retina. Foveolar thickness was increased to 397 µ. Treatment was initiated with oral corticosteroids (prednisolone 0.5 mg/kg/day). At the one-week follow-up, left visual acuity improved to 6/12+2. Hardly any cystic changes were noted, with fewer hyper-reflective bands and less disruption at the outer layer. Treatment with prednisolone was continued and lutein capsules (20 mg/day) were added. At three weeks, the patient reported a return to normal vision, with left visual acuity of 6/6-2 unaided. On OCT, near-complete restoration of the macular structure was visualized. Although these results show positive clinical outcomes with combined oral corticosteroids and lutein over a short time for a typical case of laser-induced maculopathy, further review is recommended to determine the ideal treatment regimen.

Radiobiological effects and medical applications of non-ionizing radiation

Radiation is used in medicine to diagnose and treat diseases but it can also cause harm to the body by burning or mutation. This depends on whether the radiation is ionizing or nonionizing. Despite its vast applications in surgery, dermatology and cosmetics, little is taught and thus known about non-ionizing radiation. This review article discusses the fundamentals of non-ionizing electromagnetic radiations. The main aim is to extensively explain the different types of non-ionizing radiation. This will equip students and medical personnel with knowledge on different medical applications and expose them to a variety of specializations in medicine that utilize non-ionizing radiation. The article discusses the physics, hazard, means of protection and medical application of each type of radiation: ultraviolet radiation, light (both visible light and LASER), infrared radiation, microwaves and extremely low frequency radiation separately. It presents these terms in a simple manner that avoids rigors mathematics and physics, which makes them comprehensible for medical students. The development of new diagnostic and therapeutic approaches could also lead to increased hazards to the body unless they are treated with precaution. If not adequately monitored, a significant health risk may be posed to potentially exposed employees. Hence proper dosage should be used for non-ionizing radiation. This is only possible through understanding of the risks/benefits of these radiations by studying the physics and radiobiological effects of each individual radiation.

Near-Infrared Reflectance Imaging in Retinal Diseases Affecting Young Patients

Near-infrared reflectance (NIR) is a noninvasive, contactless, and rapid in vivo imaging technique for visualizing subretinal alterations in the photoreceptor layer, retinal pigment epithelium, and choroid. The present report describes the application of this imaging method in retinal and choroidal pathologies affecting young patients where scarce cooperation, poor fixation, and intense glare sensation can result in a challenging clinical examination. A literature search of the MEDLINE database was performed using the terms "near-infrared reflectance" and "spectral-domain optical coherence tomography." Articles were selected if they described the diagnostic use of NIR in children or young adults. Of 700 publications, 42 manuscripts published between 2005 and 2020 were inherent to children or young adults and were considered in this narrative literature review. The first disease category is the phakomatoses where NIR is essential in visualizing choroidal alterations recognized as cardinal biomarkers in neurofibromatosis type 1, microvascular retinal alterations, and retinal astrocytic hamartomas. Another diagnostic application is the accurate visualization of crystals of various nature, including the glistening crystals that characterize Bietti crystalline dystrophy. Acute macular neuropathy and paracentral acute middle maculopathy represent a further disease category with young adulthood onset where NIR is not only diagnostic but also essential to monitor disease progression. A further interesting clinical application is to facilitate the detection of laser-induced maculopathy where funduscopic examination can be normal or subnormal. In conclusion, NIR imaging has a noninterchangeable role in diagnosing certain retinal diseases, especially in children and young adults where there is scarce collaboration and a lack of evident clinical findings. Moreover, this technique can reveal unique retinal and choroidal biomarkers highly specific to rare conditions.

Effect of Retinal Injury Induced by Laser Photocoagulation on Visuospatial Memory in Mouse Model

Visual pathway reveals the connection between neuronal activity of the brain and eye. The neural networks of brain amplify the retinal signals resulting in the formation of visual image. The laser injury in the retina may affect the visual pathway and may lead to disruption of neuronal signals/activity. Therefore, we aimed to study the effect of retinal injury induced by laser on cognitive abilities in laser-induced mouse model. We have established laser model to understand the relation between retina and brain by disrupting retinal pigment epithelial (RPE) layer and evaluate the effect of laser-induced retinal injury on visuospatial memory. Age- and sex-matched C57BL/6J male mice were taken for conducting the experiments. The laser model was established by using laser photocoagulator to disrupt the RPE layer of the retina. After defined irradiation of laser onto mouse retina, the fundus fluorescein angiography was performed to confirm the laser spots. The visuospatial and short-term memory was performed using neurobehavioral test, that is, Morris water maze (MWM), and passive avoidance, respectively. In MWM experiment, results showed that escape latency time, which was taken by healthy and laser-injured mice was comparable. This was further validated by another neurobehavioral analysis, that is, passive avoidance that showed nonsignificant difference between these two groups using independent t -test. Visuospatial memory may not be affected by retinal injury induced by laser photocoagulation. It may depend on the power of the laser and duration of the laser. The severe injury in the retina such as optic nerve damage may cause dysfunctioning of visual pathway.

Intravitreal aflibercept treatment for choroidal neovascularization secondary to laser pointer

A 15-year-old male was presented with blurred vision in his right eye for 2 weeks. The patient had a history of looking with the right eye for 5–6 s at a distance of 20 cm from green laser beam (class 3a, 5 mW, 532 nm). Dilated fundus examinations revealed a yellow lesion in the right eye, resulting in loss of foveal reflection at the fovea. Fundus fluorescein angiography (FFA) images and spectral-domain optical coherence tomography (OCT) scans were compatible with active classic choroidal neovascularization (CNV). A single dose of intravitreal aflibercept was performed to the right eye, and at the 1st month after the injection, the best-corrected visual acuity improved to 20/100 from 20/200. FFA showed staining of the scar with no leakage, and OCT revealed scar formation. At the follow-up visits, during 38-month follow-up, no CNV activity was observed. Intravitreal aflibercept may be an appropriate treatment option in cases with laser pointer injury-induced CNV.

Optical Gap Biomarker in Cone-Dominant Retinal Dystrophy

PURPOSE

To characterize the progression of optical gaps and expand the known etiologies of this phenotype.

DESIGN

Retrospective cohort study.

METHODS

Thirty-six patients were selected based on the identification of an optical gap on spectral-domain optical coherence tomography (OCT) from a large cohort of patients (N = 746) with confirmed diagnoses of inherited retinal dystrophy. The width and height of the gaps in 70 eyes of 36 patients were measured by 2 independent graders using the caliper tool on Heidelberg Explorer. Measurements of outer and central retinal thickness were also evaluated and correlated with gap dimensions.

RESULTS

Longitudinal analysis confirmed the progressive nature of optical gaps in patients with Stargardt disease, achromatopsia, occult macular dystrophy, and cone dystrophies (P < .003). Larger changes in gap width were noted in patients with Stargardt disease (78.1 μm/year) and cone dystrophies (31.9 μm/year) compared with patients with achromatopsia (16.2 μm/year) and occult macular dystrophy (15.4 μm/year). Gap height decreased in patients with Stargardt disease (6.5 μm/year; P = .02) but increased in patients with achromatopsia (3.3 μm/year) and occult macular dystrophy (1.2 μm/year). Gap height correlated with measurements of central retinal thickness at the fovea (r = 0.782, P = .00012). Interocular discordance of the gap was observed in 7 patients. Finally, a review of all currently described etiologies of optical gap was summarized.

CONCLUSION

The optical gap is a progressive phenotype seen in an increasing number of etiologies. This progressive nature suggests a use as a biomarker in the understanding of disease progression. Interocular discordance of the phenotype may be a feature of Stargardt disease and cone dystrophies.

[Lege artis eye coverage performed during gynecological/urological laser surgery. Results of a survey of nursing experts]

BACKGROUND

Intraoperative eye protection is generally important during surgery in patients under general anesthesia. There are, however, challenges that arise when a laser is used intraoperatively. In gynecological and urological diseases lasers are increasingly being used for treatment but a lege artis eye cover or protection has not yet been investigated in the international literature.

OBJECTIVE

According to nursing experts, how is a lege artis eye coverage performed during gynecological and urological laser surgery?

MATERIAL AND METHODS

In order to answer the research question, standardized expert interviews were carried out via telephone, direct face to face interviews and e‑mails with experts from specialized clinics in Austria. The results of a nonsystematic literature search formed the basis for the interview guidelines.

RESULTS

In this study 11 experts agreed to participate in a qualitative survey. The result of the interviews recommended the use of skin-friendly plasters in combination with a vitamin D eye ointment, special plasters/covers and/or laser safety goggles with a vitamin D eye ointment and NaCl dressings. In addition to the direct protection of the eye, a periodic intraoperative eyelid closure check must be performed.

CONCLUSION

The findings from the expert interviews are to be understood as practice recommendations. Further research is needed in the future.

Best zero level for external ICP transducer

BACKGROUND

Continuous monitoring of intracranial pressure (ICP) was introduced in the 1950s. For correct ICP recordings, the zero-reference point for the external pressure gauge must be placed next to a head anatomical structure. We evaluated different anatomical points as zero reference for the ICP device at different head positions and their relation to brain centre (BC), foramen of Monro (Monro), and brain surface.

METHODS

Patients referred for neuroimaging due to e.g. headache all having normal 3D MRI scans were selected. Monro, BC, Orbit(O), external auditory meatus (EAM), and orbito-meatal (OM) line were identified and projected to mid-sagittal, or axial images. Each scan was evaluated like lying supine, 45° head elevations, upright, and 45° lateral position. Distances from skin to brain surface, BC, and Monro were measured. All values are presented as mean ± SD and/or range in millimetre. For conversion to mmHg, millimetre was multiplied by 0.074.

RESULTS

Twenty MRI scans were examined. A zero reference at EAM or glabella was ideal at BC when head was strict supine or in the lateral position. At 45° head elevation, an overestimation of the BC-ICP by 4.8 ± 0.8 and in upright 5.6 ± 0.5 mmHg was found, and 45° lateral underestimated ICP-BC by 6.3 ± 1.0 mmHg. Monro was situated 45 ± 5 mm rostral to the mid-OM line and 24 (18-31) mm inferior and 13 (8-17) mm in front of BC. A zero-reference point aligned with the highest point of the head underestimated BC-ICP and Monro-ICP. If the ICP reading was added 5.9 or 6.3 mmHg, respectively, a deviation from BC-ICP was ≤ 1.8 mmHg and Monro-ICP was ≤ 0.9 mmHg in all head positions.

CONCLUSIONS

EAM and glabella are defined anatomical structures representing BC when strict supine or lateral but with 12 mmHg variation with different head positions used in clinical practice. The OM line follows Monro at head elevation, but not when the head is turned. When the highest external point on the head is used, ICP values at brain surface as well as Monro and BC are underestimated. This underestimation is fairly constant and, when corrected for, provides the most exact ICP reading.

Handheld laser devices and laser-induced retinopathy (LIR) in children: an overview of the literature

Handheld laser devices are easily available to purchase through the internet and unregulated marketplaces at a relatively low cost. They are particularly attractive to children as they are seen as 'high tech', brightly coloured, and known to be able to burn holes in objects such as balloons. There is a widespread lack of knowledge about the risks of viewing the beam emanating directly from handheld lasers, and particularly those with high-output powers. The number of reported laser induced retinopathy (LIR) injuries in children is on the increase in the United Kingdom and represents a major public health issue. The number of individuals affected by LIR is likely to be underestimated owing to lack of presentation to health professionals, general poor awareness and non-reporting by children after the incident. The presentation of LIR is highly variable and dependent on many factors including type of laser, length of exposure and how it is administered. In this article, we review the features of retinal damage associated with inadvertent or deliberate laser administration using a handheld laser device. We highlight the importance of educating the wider public about this increasing problem; children who play with these devices are usually completely unaware of the long-term consequences of laser damage to the eye. It is also important that the features of LIR are recognised by health professionals involved in eye care as they can be mistaken for retinal dystrophies, particularly if the history of laser exposure is not volunteered or elicited.

Retinal burns from laser pointers: a risk in children with behavioural problems

OBJECTIVE

To explore self-inflicted retinal burns from laser pointers in children.

METHODS

Literature review of laser pointer retinal injuries in childhood and online survey of UK Consultant Ophthalmologists. A cohort of local children with self-inflicted injury is described. The matter is topical. We review progress in recent legislation and policy change in the UK.

RESULTS

Four of 77 case reports of laser burns in childhood analysed reported psychological or behavioural issues. Three of four children in our cohort had such issues. Delay in diagnosis occurred in two of our patients. Structural retinal damage persisted for over 12 months in all four children (seven eyes). Our survey of UK ophthalmologists found 159 cases of injury (85% male), 80% under 20 years of age. The majority of the laser pointers were purchased online. Many patients (36%) suffered moderate vision loss (6/18 to 6/60 Snellen), while 17% (at least 11 patients) suffered severe vision loss (<6/60 Snellen).

CONCLUSION

We highlight the risk of macular damage and vision loss from handheld lasers specifically in children with behavioural, learning or mental health issues. The diagnosis may be difficult or delayed in such children. In children with uncertain macular changes, ophthalmologists should explore the history for possible instances of exposure to handheld lasers pointers. Regulatory authorities and manufacturers of handheld lasers need to be aware of the risk to children. Furthermore, there is a need to better inform parents, carers and teachers of the risk of ocular self-injury from such lasers pointers.