Dysphotopsia Following Laser Peripheral Iridotomy

Credit Valley EyeCare

Status: Completed

Conditions: Narrow Angle Patients at Risk for Angle Closure Glaucoma

Treatments: Procedure: Nd:YAG Laser Peripheral Iridotomy; Device: Neodymium-doped: Yttrium Aluminum Garnet (Nd:YAG) laser

Study type: Interventional

Funder types: Industry

Identifiers

NCT01758237

CVEC-LPI

Details and patient eligibility

About

To establish the correlation of the location of the Nd:YAG laser peripheral iridotomy to the post operative visual symptoms experienced by some patients. The investigators hypothesize that fully uncovered laser peripheral iridotomy will produce less significant dysphotopsia, due to avoidance of the prismatic effect produced by the tear film than those covered.

Full description

Nd:YAG LPI is a frequently performed procedure for patients who have narrow angles at risk of acute angle closure glaucoma, pupillary-block conditions, chronic angle closure, and pigment dispersion syndrome. Most complications associated with the procedure are benign and include intraocular pressure (IOP) spike, transient uveitis, hyphema, corneal or lens damage and closure of the iridotomy. Visual disturbances have been also reported but only a few papers address this specific issue. The rate of these symptoms vary between 2.7% and 4%. It is believed that these symptoms are associated with the fact that light enters through the LPI and thus creating abnormal visual symptoms. Hence it has been suggested to carefully place the LPI so that the eyelid fully covers the LPI, therefore preventing light getting through. However, reports of patients with fully covered LPIs and visual disturbances have led to hypothesize the theory that even when fully covered by the eyelid, light can access through the LPI by a base-up prism created by the tear meniscus at the lid margin. Therefore, placement of the LPI, fully covered, partially covered or totally uncovered can potentially lead to equally significant symptoms. This study will attempt to address the issue of placement of the LPI in relationship with visual symptoms.

Enrollment: 214 patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Able and willing to make the required study visit
• Able and willing to give consent and follow study instructions
• An indication to undergo laser peripheral iridotomy (narrow angles, occludeable angle at risk of acute angle closure, pupil block condition, chronic angle closure, pigment dispersion syndrome)

Exclusion criteria

• Previous intraocular surgery
• Best corrected visual acuity worse than 20/40
• Asymmetrical ptosis of more than 2mm
• Any active intraocular inflammation
• Acute attack of angle closure glaucoma

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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214 participants in 2 patient groups

Superior Laser Peripheral Iridotomy

Experimental group

Description:

Neodymium-doped: Yttrium Aluminum Garnet (Nd:YAG) laser peripheral iridotomy was performed on the superior aspect of the iris in the eye being treated. This will be in the 11 to 1 o'clock position.

Treatment:

Device: Neodymium-doped: Yttrium Aluminum Garnet (Nd:YAG) laser

Procedure: Nd:YAG Laser Peripheral Iridotomy

Temporal Laser Peripheral Iridotomy

Experimental group

Description:

Neodymium-doped: Yttrium Aluminum Garnet (Nd:YAG) laser peripheral iridotomy was performed on the temporal aspect of the iris in the eye being treated. The position will be in the 2 to 4 o'clock in the left eye and 8 to 10 o'clock in the right eye.

Treatment:

Device: Neodymium-doped: Yttrium Aluminum Garnet (Nd:YAG) laser

Procedure: Nd:YAG Laser Peripheral Iridotomy