Eye Protection for Phototherapy Patients David Turner 2017

Anatomy

UVR Transmission <295nm 0% <1% 2% >295nm Most energy absorbed by conjunctiva, cornea and lens

Chromatic Aberration Due to different focal lengths of different wavelengths (colours) UV is not well focussed on the retina

Risks Acute UVB Photokeratitis Conjunctivitis UVA Cataractogenesis Chronic

Sources UVB Environmentally UVB is only encountered significantly during summer when the angle of the sun is high. Artificially inside phototherapy cubicles. Thus suitable eye or face protection needs to be worn during treatment. This can be supplied by the equipment manufacturers although nearly all plastic and even glass lenses will block UVB

Sources UVA UVA exists in the environment from both the sun and artificial “energy saver” fluorescent lamps. UVA is only partially blocked by glass. Spectacles with glass lenses do not offer sufficient protection. UVA is blocked by a variety of plastics, polycarbonate being one of the best due to it’s clarity and strength

PUVA Psoralen diffuses into the lens of the eye. On exposure to UVA psoralen binds with DNA and certain amino acids such as tryptophan The lens rarely sheds any of its cells so photoproducts tend to accumulate Patients who have a lens’s absent risk damage to the retina from UVA therapy. Patients with cutaneous photosensitivity do not generally appear to have enhanced eye problems with the exception of Xeroderma Pigmentosa. Sporadic reports exist of Actinic Prurigo, Hydroa Vacciniform and Photosensitive Eczema patients having eye problems.

Evidence Lerman S, Megaw J, Willis I. Psoralens are used in treating psoriasis. Drug can be found in lenses of rats injected (intraperitoneally) with 4-8 mg/kg of 8-methoxypsoralen (8-MOP) Its presence can lead to a photosensitized enhancement of lenticular fluorescence. Photo-addition products are generated with certain amino acid residues in the lens proteins which may result in the permanent retention of this compound within the ocular lens. Free 8-MOP can also be detected in human lenses for at least 12 hr following oral ingestion. Since the free 8-MOP tends to diffuse out of the lens during this period of time (as long as photic stimulation is prevented) it may be possible to prevent these photochemical reactions if the patient avoid exposure to ambient light for 12-24 hr immediately following ingestion of the drug. It may also be possible to protect these patients with special glasses which are capable of reflecting all UV radiation (up to 400 nm) while completely transmitting the visible radiation (400-750 nm). Lerman S, Megaw J, Willis I.

Evidence 25 Year prospective Study of PUVA patients that used eye protection routinely In some animal species, exposure of the unprotected eye to psoralen plus ultraviolet A (PUVA) therapy induces lens opacities. The relevance of these animal findings to human beings is not established. However, some case reports suggest that PUVA in human beings may increase the risk of lens abnormalities. Between 1977 and 2004 the PUVA follow-up study has periodically monitored the ocular status of 1237 cohort members with psoriasis using structured eye examinations Age-adjusted incidence of cataract did not increase significantly (incidence rate ratio = 1.04, 95% confidence interval = 0.82-1.31). Analyses showed increasing exposure to PUVA was not associated with a higher risk of cataract. Our cohort principally enrolled middle-aged or older patients so our data do not permit us to assess the effects of PUVA on the eyes of younger persons. Increasing exposure to PUVA does not increase cataract risk among persons using eye protection at the rates used in our cohort. Malanos D, Stern RS.

Evidence Deleu H, Roelandts R. Short- and long-term ocular side effects of psoralen plus UVA (PUVA) therapy in 82 patients who refused to wear UVA blocking sunglasses (321.7 +/- 328.8 J/cm2 of UVA in 148.8 +/- 113.9 exposures over 2-4 years). Compared with findings obtained in 749 patients who shielded their eyes (402.6 +/- 302.2. J/cm2 of UVA in 167.8 +/- 136.9 treatments over 2-6 years). 20 patients refusing eye sun protection developed conjunctiva hyperaemia 21 patients decreased lacrimation. Among patients who adequately protected the eyes 5 cases of conjunctiva hyperaemia 1 case of decreased lacrimation. Lens opacities did not develop in any patient. Adequate eye sun-protection is thus needed to avoid acute toxicity of cornea and conjunctiva but lens opacities do not appear to be a side effect of long-term PUVA-therapy. Deleu H, Roelandts R.

Estimated Action Spectrum of Lens to PUVA What do we need to block? Sunlight incident on lens Absorption spectrum of 8-MOP Relative effectiveness of PUVA on inducing cataracts Moseley H, Cox NH, Mackie RM

UVA Transmission limits Wavelength range (nm) <360 361-370 371-380 381-390 391-400 401-420 Arbitrary Limit 1% 2% 5% 10% - - Max Transmission 0.0075% 0.0052% 0.14% 0.6% 18% 75% Bolle Bolle Rayban Rayban Pulsafe Pulsafe Minimum Transmission 0.00013% 0.00002% 0.00002% 0.00003% 0.001% 0.011% Woolworths ‘Garage’ Woolworths Calvin Klein ‘Garage’ Uvex 803 Visor Garage represents unbranded samples purchased from local shops or garage forecourts Moseley H, Cox NH, Mackie RM

Protective Transmission Uvex 803 Face shield Dotted line shows guideline limits All pass as made from polycarbonate. Cost of sunglasses is not a factor. Boots “Own brand” sunglasses Rayban sunglasses Otman SG, El-Dars LD, Edwards C et al

Available Test Equipment Spectrometer not available in many centres that can measure Moseley’s bands individually More common to have a test meter

Available UVA Sources Local Treatment Local treatment units are more commonly available than canopies. Either are suitable. PUVA canopy

Evidence Equipment is Suitable Protective equipment Test equipment

Suitable Spectacles Tint or colour has nothing to do with blocking UV It is the properties of what the lens is made from. UV blocking spectacles can be clear. Clear UV coating can be applied to existing spectacles Spectacles we provide are not popular and patients often source their own

Checking Suitability A test meter that measures UVA

Checking Suitability Measure the output from a UVA source…typically a PUVA hand or foot unit

Checking Suitability Measure the output again with the lens over the detector. Check BOTH lenses

Checking Suitability The output from this source would need to fall to less than 0.11 (1% of 11.45) to be suitable here the output reduces to zero Experience has shown well coated spectacles will reduce the transmission to zero

UVR Protecting lens Coatings Coating designation Manufacturer Colour UVX Essilor Clear UV400 Norville Very slight brown UV Guard Sola Clear Claret UV ET Zeiss Red UV PLS 530 Norville Orange

Contact lenses Most contact lens tested have poor UVA protection. Protection factors of 100 are required Only ones suitable Otman SG, El-Dars LD, Edwards C et al.

Employees There are EU mandatory limits for employees exposure to UV. Directive 2006/25/EC Artificial Optical Radiation Directive 315 – 400 HUVA = 104 Jm-2 Unwieghted. For the eye is it 1 Jcm-2 of UVA in any 8 hour period. Medical Physics department suit have available documentation to ensure this limit is not breached and if so what protective measures are required.

Conclusion All spectacles will block UVB Certain plastic spectacle lenses block UVA, often inexpensive and common ones. PUVA patients eyes are particularly sensitive to UVA. Acute inflammatory effects and the theoretical potential for long term ocular opacity mean eye protection is required. Contact lens alone are generally not suitable Protective spectacles need to be tested to ensure safety. With a source of around 10mWcm-2 a level of 0.1mWcm-2 is acceptable. Zero is typical. From ingestion of psoralen protective spectacles should be worn for at least 12 hours.

References Lerman S, Megaw J, Willis I. Potential ocular complications from PUVA therapy and their prevention. J Invest Dermatol 1980; 74:197–9. British Photodermatology Group. British Photodermatology Group guidelines for PUVA. Br J Dermatol 1994; 130:246–55. Stern RS, Parrish JA, Fitzpatrick TB. Ocular findings in patients treated with PUVA. J Invest Dermatol 1985; 85:269–73. Stern RS. Ocular lens findings in patients treated with PUVA. Photochemotherapy Follow-Up-Study. J Invest Dermatol 1994; 103:534–8. Malanos D, Stern RS. Psoralen plus ultraviolet A does not increase the risk of cataracts: a 25-year prospective study. J Am Acad Dermatol 2007; 57:231–7. Calzavara-Pinton PG, Carlino A, Manfredi E et al. Ocular side effects of PUVA-treated patients refusing eye sun protection. Acta Derm Venereol Suppl 1994; 186:164–5.

References Moseley H, Cox NH, Mackie RM. The suitability of sunglasses used by patients following ingestion of psoralen. Br J Dermatol 1988; Moseley H, Jones SK. Clear ultraviolet blocking lenses for use by PUVA patients. Br J Dermatol 1990; Diffey BL, Miller JA. A comment on the routine testing of sunglasses in photochemotherapy. Br J Dermatol 1980; Deleu H, Roelandts R. Protecting the eye from ultraviolet A radiation during photochemotherapy. Photodermatol Photoimmunol Photomed 1990; 7:233–6. Otman SG, El-Dars LD, Edwards C et al. Eye protection for ultraviolet B phototherapy and psoralen ultraviolet A patients. Photodermatol Photoimmunol Photomed 2010; 26:143–50.