Welding-arc Maculopathy

Welding-arc maculopathy may develop following prolonged exposure to welding arc radiation without adequate protection of eyes. It generally affects young people because of their occupational lack of knowledge and also due to presence of relatively clear ocular media. Most common injury with welding arc radiation is photophthalmia due to ultraviolet (UV) light absorption. Welding-arc maculopathy may be underreported because of its transient clinical features, which may be masked by associated photokeratitis.

The effect of light on retina is being recognised since the time of Plato, who gave description of eclipse blindness.

Photic (related to light) retinopathy is a generalised term used for retinal damage produced by light. This may be due to solar viewing or may be produced even by use of operating microscope.

Increase in retinal temperature is below photocoagulation thresholds. The injury is due to photochemical effects from UV and short blue wavelength exposure. Similar photochemical macular burns may take place after brief exposure to the flash associated with short-circuiting of a high-tension electric current. Use of drug phenothiazine may increase the susceptibility to damage due to the welding-arc radiation.

In metal-arc inert gas welding, the arc is ensheathed with inert gas to prevent oxidation of molten metal. The gas changes emitted radiation into visible and infra-red range, which may produce thermal and photochemical damage to the retina. This is unlike electric arc where the radiation is predominantly in UV range.

The appearance of retinal lesions and clinical course of welding arc exposure are similar to those of solar retinopathy. However, welding-arc maculopathy requires more prolonged exposure as compared to solar retinopathy.

 

References

Agarwal Anita. Gass’ Atlas of Macular Diseases Volume 1 Fifth Edition. Elsevier Saunders 2012. P 742.

Agarwal Amar. Fundus Fluorescein and Indocyanine Green Angiography- A Textbook and Atlas. Slack Incorporated 2008. P 150-151.

Gupta Vishali, Gupta Amod, Dogra MR. Atlas Optical Coherence Tomography of Macular Diseases and Glaucoma Third Edition. Jaypee Brothers Medical Publishers (P) Ltd 2010. P 442.

Nema HV, Nema Nitin. Textbook of Ophthalmology Sixth Edition. Jaypee Brothers Medical Publishers (P) Ltd 2012. P 313.

Rishi Pukhraj, Rishi Ekta, Sharma Tarun, Bhende Muna, Sen Parveen, Ratra Dhanashree, Gopal Lingam. The Sankara Nethralaya Atlas of Fundus Fluorescein Angiography Second Edition. Jaypee Brothers Medical Publishers (P) Ltd 2013. P 254- 257. 

Yanoff Myron, Duker Jay S. Ophthalmology Fourth Edition. Elsevier Saunders 2014. P 461- 466.

Baxter Peter J, Aw Tar-Ching, Cockcroft Anne, Durrington Paul, Harrington J Malcolm. Hunter’s Diseases of Occupations Tenth Edition. Taylor & Francis Group, LLC 2010. P 652.

Roy Hampton, Fraunfelder Frederick W, Fraunfelder Frederick T, Tindall Renee, Jensvold Bree. Roy and Fraunfelder’s Current Ocular Therapy Sixth Edition. Saunders Elsevier Inc. 2008. P 571- 572.

Ryan Stephen J, Sadda SriniVas, Hinton David. Retina Volume 1 Fifth Edition. Elsevier Saunders 2013. P 1557- 1558.

Rom William N, Markowitz Steven B. Environmental and Occupational Medicine Fourth Edition. Lippincott Williams & Wilkins, a Wolters Kluwer business 2007. P 700- 701.

Denniston Alastair KO, Murray Philip I. Oxford Handbook of Ophthalmology Third Edition. Oxford University Press 2014. P 592.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3730511

http://bjo.bmj.com/content/bjophthalmol/75/7/433.full.pdf

Symptoms include

  • Unilateral or bilateral diminution of vision.
  • Post injury visual acuity may be normal or decreased.
  • Scotoma.
  • Photophobia (increased sensitivity to light).
  • Metamorphopsia (distorted vision).
  • Chromatopsia (objects appear abnormally coloured e.g. erythropsia shows reddish colour).
  • Afterimage (persistence of image even after removal of stimulus).

 

Mechanism

There is evidence which suggests that the retinal damage due to welding-arc exposure is probably photochemical rather than thermal, and is primarily caused by the wavelengths at the blue end of the light spectrum.

Similar macular burns may occur following brief exposure to the flash associated with short-circuiting of high-tension electric current.

 

Prolonged welding-arc exposure over a period of minutes or longer may cause

  • Facial burn.
  • Decreased pupillary response.
  • Central scotoma.
  • Decrease in vision.
  • Concentric loss of peripheral field.

 

Diagnosis depends upon the clinical history, clinical features, and investigative procedures.

Besides clinical history of exposure with characteristic symptoms, patient presents with clinical signs as

A yellow oedematous lesion with greyish borders may develop acutely in the foveal region. There may be multiple spots. Slight exposure may reveal an altered foveal light reflex. With time, this is replaced by irregularity in retinal pigment epithelium (RPE). In more severe cases, the yellow spot may change to a reddish spot. This may lead to foveal depression or a permanent lamellar defect.

Fluorescein angiography may be normal, but more severe damage may cause foveal RPE defects.

Optical coherence tomography (OCT) characteristically shows well-defined outer retinal hypo-reflective space which primarily involves photoreceptor inner and outer segment layers.

Amsler grid testing may delineate small central or paracentral scotoma.

 

 

Differential diagnosis

  • Solar retinopathy.
  • Light flash or arc, produced by high-voltage electrical short-circuiting.
  • post-surgical photic retinopathy.
  • Accidental laser exposure.

 

 

There is no effective therapy for welding-arc maculopathy.

Vision usually improves with passage of time. Some patients may be left with permanent defects and loss of vision.

Education of people may reduce visual morbidity.

  • PUBLISHED DATE : Jul 28, 2017
  • PUBLISHED BY : NHP Admin
  • CREATED / VALIDATED BY : Dr. S. C. Gupta
  • LAST UPDATED ON : Jul 28, 2017

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