Sir,

Laser-assisted hair removal (photo-epilation) is becoming an increasingly popular treatment. It relies on the principle of selective photothermolysis whereby use of an appropriate wavelength and pulse duration of light causes injury that is confined to the desired target tissue while sparing surrounding structures.1, 2 We report a case of iris damage and acute pigment dispersion after the use of long-pulsed infra-red (LPIR) alexandrite laser for photo-epilation of the eyebrow.

Case report

A 38-year-old woman presented with left ocular discomfort associated with photophobia, redness, and blurred vision. She had undergone photo-epilation of her eyebrows earlier that day with a 755 nm LPIR alexandrite laser (20 ms pulse duration, 22 J/cm2 fluence, 10 mm diameter spot). Although treatment to her right eyebrow was uneventful, she had experienced extreme discomfort when the laser beam was switched to the area below her left eyebrow.

Examination revealed a constricted left pupil with marked anterior chamber (AC) activity but normal intraocular pressure (IOP) and visual acuity (VA). Acute anterior uveitis was diagnosed and treatment with a topical steroid and cycloplegic started. Upon follow-up, AC activity persisted and the IOP increased to 37 mmHg. There was also evidence of pigment dispersion in the AC with pigmentation of the trabecular meshwork (Figure 1). A topical β-blocker was added to her treatment.

Figure 1
figure 1

Pigment dispersion over iris surface with increased pigmentation of the trabecular meshwork.

Eight weeks after initial presentation, this patient only had minimal photophobia. The left eye was white and quiet with normal IOP on medication. A marked superior iris transillumination defect was then apparent (Figure 2). No other features of pigment dispersion syndrome were evident clinically and an Optical Coherence Tomography scan ruled out posterior bowing of the iris. There was no history of herpes zoster ophthalmicus. It was concluded that all the features of this case were attributable to accidental iris damage with the LPIR laser resulting in acute pigment dispersion and raised IOP. The laser protection agency was notified and LPIR laser treatment within the peri-orbital region has since been suspended.

Figure 2
figure 2

Superior iris transillumination defect.

Comment

In photo-epilation, use of an appropriate wavelength and pulse duration of light causes selective thermal damage mediated by follicular melanin.1, 2 The alexandrite laser system, with a wavelength of 755 nm, is well absorbed by follicular melanin. The amount of energy absorbed also depends on interference from other melanin-containing structures.2, 3 Hair follicles lie about 3 mm below the skin surface. However, thermal damage from the alexandrite laser can occur at several millimetres depending on user settings and skin type.

Before photo-epilation, this patient had her eyes closed and covered with damp cotton pads. Owing to the Bell's phenomenon, elevation of the globe with lid closure would have resulted in proximity of the superior iris to the area being treated. As the iris is a melanin-containing structure, exposure to the penetrating laser beam would have resulted in absorption of energy and subsequent damage with inflammation and pigment dispersion. The presence of superior iris atrophy is consistent with this mechanism.

At follow-up after 1 year, this patient was on no treatment to the affected eye and had normal VA and IOP. Long-term ocular complications from laser damage in this case are unknown. Recent guidelines have warned against the high potential for thermal damage to the iris and retina in patients who have photo-epilation close to the eye.4 Strict safety measures, such as metal lenses, are required in these circumstances.