Laser peripheral iridotomy (LPI) is performed in patients with narrow anterior chamber angles at risk for angle-closure glaucoma. Argon or green diode and Nd:YAG lasers are often used sequentially in dark irides to create an iridotomy with a minimum amount of laser energy. Posterior segment complications of LPI are uncommon and generally related to direct laser-induced damage.1Herein we report the development of a stage 1 macular hole following LPI and its resolution with the aid of the optical coherence tomography/scanning laser ophthalmoscope (OCT/SLO) (Ophthalmic Technologies Inc, Toronto, Ontario).
A 60-year-old woman with a history of ocular trauma in the right eye underwent a routine eye examination. Corrected visual acuity was 20/25 OD and 20/20 OS with an intraocular pressure of 16 mm Hg OU. Examination revealed brown irides and a mild cataract with angle recession in the right eye and a narrow, potentially occludable anterior chamber angle in the left eye.
An LPI was performed on the left eye at the 1-o’clock position. A total of 387 applications were delivered with a 532-nm green diode laser using 600 to 800 mW per application, a pulse duration of 50 milliseconds, and a spot size of 75 μm followed by 9 pulses in the single-burst mode with the Nd:YAG laser, delivering a total energy of 49.2 mJ. The initial opening and subsequent enlargement were performed with the Nd:YAG laser.
Two days postoperatively the patient complained of a central scotoma she noted immediately after the LPI. The visual acuity was 20/30 OS. Dilated fundus examination revealed a yellow dot in the fovea (Figure 1A). The OCT/SLO images demonstrated vitreofoveal traction consistent with a stage 1A macular hole (Figure 1B). Five months postoperatively, the vision improved to 20/20 with resolution of the scotoma. Repeat OCT/SLO imaging (Figure 2) demonstrated vitreous separation with spontaneous resolution of the macular hole and return to normal foveal contour.
Eight days after laser peripheral iridotomy. A, Fundus photograph of the left eye demonstrates a yellow spot in the foveola (short arrow), a stage 1 macular hole. B, Optical coherence tomography/scanning laser ophthalmoscope image demonstrates vitreofoveal traction (long arrow) and foveola floor elevation (arrowhead) corresponding to the fundus photograph.
Serial ocular coherence tomography/scanning laser ophthalmoscope images. A, Seven weeks postoperatively. The posterior hyaloid face (long arrow) is completely detached with persistent foveola floor elevation (arrowhead). B, Five months postoperatively. The posterior hyaloid is completely detached and out of view with resolved foveola elevation (arrowhead).
Reported complications of LPI include transient elevation of the intraocular pressure, localized corneal opacities and endothelial damage, iris bleeding, and lens damage.2,3Macular hole formation has been reported following Nd:YAG posterior capsulotomy.4However, we are unaware of previous reports of macular hole formation complicating LPI and could find no reference to it when we searched MEDLINE.
The mechanism of macular hole formation in our patient is most likely related to the concussive force exerted by the Nd:YAG laser. As the laser is applied at the iridotomy site, plasma formation and photodisruption produce shock waves that propagate through to the anterior hyaloid face and the vitreous body. An additional potential mechanism includes the thermal effects of the diode laser on the anterior vitreous. The resultant concussive and thermal effect on the vitreous may then cause a perifoveal vitreous detachment with subsequent foveolar traction and a stage 1 macular hole formation.
In conclusion, stage 1 macular hole formation is a possible complication of LPI. This may be followed by complete posterior vitreous detachment and resolution of the macular hole with improvement in symptoms.
Correspondence: Dr Gentile, New York Medical College/The New York Eye and Ear Infirmary, 310 East 14th St, New York, NY 10003 (firstname.lastname@example.org).
Financial Disclosure: None reported.
Funding/Support: This report was supported by the Department of Ophthalmology Research Fund of the New York Eye and Ear Infirmary and the Norma Lazar Ophthalmology Research Fund.
Anderson JE, Gentile RC, Sidoti PA, Rosen RB. Stage 1 Macular Hole as a Complication of Laser Iridotomy. Arch Ophthalmol. 2006;124(11):1658-1660. doi:10.1001/archopht.124.11.1658