An iridotomy and an iridectomy do the same job. Each makes an opening in the iris, the colored part of the eye, so fluid can reach the eye’s drain instead of pushing the iris forward. The difference is in how the opening is made. An iridotomy is a pinpoint hole burned with a laser in the office, and an iridectomy cuts out a small piece of iris during surgery. If a doctor has recently told you that you have narrow angles, the procedure you are most likely being offered is the quick laser one, not surgery, since the laser is the usual first choice.
How the Two Procedures Differ
Fluid made behind the iris normally flows forward through the pupil and drains at the angle where the iris meets the cornea. If the iris sits too close to the lens, that flow gets stuck. The trapped fluid then bows the iris forward.1Cochrane Database of Systematic Reviews. Iridotomy to slow progression of visual field loss in angle-closure glaucoma The bowed iris can crowd or shut the drainage angle, and pressure in the eye can rise. A hole in the outer edge of the iris lets fluid pass straight from behind the iris to the front, which relieves the block and the crowding.2PentaVision. Tips and Tricks for In-Office Laser Peripheral Iridotomy Because it sits in the far outer part of the iris, usually tucked under the eyelid, it doesn’t change how the pupil looks or works for most people.
Laser iridotomy uses a laser to make that hole without cutting the eye open.3Cochrane Database of Systematic Reviews. Iridotomy to slow progression of visual field loss in angle-closure glaucoma A surgical iridectomy removes a small wedge of iris through an incision, usually in an operating room and often alongside other eye surgery such as cataract removal. When an iridectomy is done during cataract surgery, taking out a small piece at the edge of the iris or a larger wedge reaching the pupil gave similar sharpness of vision afterward.4PubMed. Visual effects of peripheral and sector iridectomy
From the patient’s side, the two feel quite different. The laser takes minutes in an exam chair with numbing drops. Surgery needs an operating room and anesthesia, either numbing drops or an injection around the eye, sometimes with sedation. The surgeon works through a small incision, grasps a piece of iris, and removes it, leaving a clear opening. Afterward the eye usually needs a patch or shield for a time and a course of prescribed drops while the incision heals. After the laser, most people return to normal activity the same day, while surgery means days to weeks of healing. Both are meant to leave a lasting opening, though a laser hole can occasionally close and need reopening.
The laser needs a clear view through the cornea and an iris it can pierce, which describes most eyes seen in an office. Surgery is usually chosen because the laser isn’t possible or because the surgeon is already inside the eye for another operation, not because it works better. Ask your doctor why if surgery is proposed.
The names are easy to mix up. “-otomy” means making a cut or opening, which matches the laser hole, while “-ectomy” means removing tissue, which matches the removed piece of iris. Paperwork may say “LPI” or “PI,” and both usually mean the laser procedure. If your form says iridectomy, ask whether it is part of another surgery you are scheduled for.
Why Doctors Recommend an Iridotomy
Laser iridotomy is the standard first treatment for people whose angles look narrow, for people with angle closure, and for sudden angle-closure attacks.5PubMed Central. Laser peripheral iridotomy induced changes in eyes with primary angle closure disease The laser works because it directly relieves fluid trapped behind the iris and helps keep the disease from getting worse.6PubMed Central. Laser peripheral iridotomy induced changes in eyes with primary angle closure disease It is also offered as prevention to people at risk of moving from a narrow angle to angle closure and then to angle-closure glaucoma, which damages vision.7Ophthalmologica Indonesiana. Clinical Outcomes of Laser Peripheral Iridotomy in Eyes with Primary Angle Closure Suspect and Primary Angle Closure
A narrow angle is often found at a routine exam, before any symptoms appear. It isn’t glaucoma yet, but it raises the chance of a sudden pressure spike. Dim light and some medicines that widen the pupil can trigger an attack.
An attack can bring severe eye pain, headache, a red eye, blurred vision, and halos around lights, sometimes with nausea or vomiting. This is an emergency that needs same-day care, because the pressure can damage the optic nerve within hours.
For people with narrow angles but no damage yet, preventive laser iridotomy looked costly over 2 years.8PubMed. Cost-effectiveness of Prophylactic Laser Peripheral Iridotomy in Primary Angle-Closure Suspects Over 6 years it became cheaper overall and gave more healthy years of sight than waiting, and it was good value in about 9 of 10 modeled scenarios.9PubMed. Cost-effectiveness of Prophylactic Laser Peripheral Iridotomy in Primary Angle-Closure Suspects
Doctors decide by looking at the angle directly with a special lens exam, and scans can add detail. The recommendation rests on how narrow the angle looks and whether it shows signs of closing. Eye pressure, the look of the optic nerve, past attacks, and a family history of angle closure all affect how strongly treatment is advised. Some people with narrow angles are watched instead of treated right away, so the diagnosis doesn’t automatically mean a procedure that day. Surgery is still chosen when the cornea is too cloudy or swollen for a clear laser view, when a laser hole keeps closing or the iris can’t hold one, or when the eye is already having surgery and the surgeon adds the opening at the same time.
What to Expect During a Laser Iridotomy
A pressure-lowering drop is usually given about an hour before the laser and again right after, to prevent a pressure spike.10EyeWiki. Laser Peripheral Iridotomy Numbing drops and drops that narrow the pupil go in next. You rest your chin on a microscope like the one used at eye exams, and a small lens is placed on the eye. That lens focuses the laser precisely on a spot in the iris and holds the eyelids and eye steady.
The doctor picks a spot, often under the upper eyelid, and fires pulses until a small opening appears, which is confirmed when fluid and light pass through it. Each pulse feels like a snap or brief sting, and the whole session is often just a few minutes. The energy is aimed at the iris, not the center of vision, so you don’t lose sight of what is in front of you.
Darker and thicker irises often need more laser energy and more pulses.11Glaucoma Today. Glaucoma Laser Therapy For very thick irises, or when bleeding is a worry, a second type of laser may be used first to prepare the spot.12Glaucoma Today. Glaucoma Laser Therapy The hole has to be large enough to stay open even if the iris swells or the pupil widens later.13EyeWiki. Laser Peripheral Iridotomy
Pressure is checked within about an hour before you leave. Vision can be blurry for a few hours, so plan a ride if your doctor advises it. Bring a list of your eye drops and medicines, and ask whether the second eye will be treated the same day or later.
Once the numbing drops wear off, a mild ache or irritation may appear, and over-the-counter pain relief usually handles it if your doctor agrees. You’ll use steroid drops for a few days to calm the inflammation the laser causes, so use them as directed even if the eye feels fine. A follow-up visit checks eye pressure and confirms the hole is open and the angle looks wider.
Does the Laser Fully Open the Angle
Eye scans taken after the laser show the drainage angle opening wider in measurable ways.14PubMed. Changes in Anterior Segment Morphology and Predictors of Angle Widening after Laser Iridotomy in South Indian Eyes The iris itself doesn’t get thinner. The change comes from the iris settling back once fluid can flow through.15PubMed Central. Anterior Segment Optical Coherence Tomography Changes to the Anterior Chamber Angle in the Short-term following Laser Peripheral Iridoplasty But in some narrow-angle eyes, parts of the angle stay closed despite a working hole.16PubMed. Residual anterior chamber angle closure in narrow-angle eyes following laser peripheral iridotomy: anterior segment optical coherence tomography quantitative study That’s why a follow-up exam should check the angle again, not just the pressure.
To confirm the hole works, the doctor looks at the iris through a microscope to see that the opening goes all the way through and that light passes through it. Looking at the angle with a special contact lens, or with a scan, shows whether it has actually widened. Pressure readings alone aren’t enough, since pressure can look normal while parts of the angle remain closed.
Some angles are crowded by something other than fluid trapped behind the iris, so a hole can’t fix the cause. One example is a plateau iris shape, in which the iris edge sits forward and crowds the angle regardless of the hole. Another is a lens that keeps thickening with age and pushes the iris forward over time. In long-standing closure, parts of the angle may also have scarred shut, so even a wider angle doesn’t reopen those areas.
If the angle stays narrow, doctors may suggest another laser that reshapes the iris, pressure-lowering drops, or lens surgery. Checkups continue either way, because the laser lowers risk but doesn’t cure glaucoma.
The hole itself can occasionally close. Swelling or pigment can partly block a small hole early on, and a hole made large enough from the start is less likely to close. If it does, the laser can usually reopen it.
Side Effects and Risks
Most people have no lasting problems. Surgical iridectomy adds risks the laser avoids, such as infection and incision problems. In the first days, a mild ache, blur, or light sensitivity is common. A brief pressure rise is the reason for the pressure check after the laser. Small bleeding in the eye can happen and usually clears. Call your doctor if pain grows or vision drops sharply.
About 9% of people notice at least one new visual symptom after the laser, most often glare or blur in about 4% each, and a line of light in about 3%.17PubMed. Comparison of New Visual Disturbances after Superior versus Nasal/Temporal Laser Peripheral Iridotomy: A Prospective Randomized Trial Your notes may call these effects dysphotopsia.18PubMed. Dysphotopsia after temporal versus superior laser peripheral iridotomy: a prospective randomized paired eye trial Where the hole sits matters. New lines of light showed up in about 11% of eyes with a hole at the top versus about 2% with a hole at the side.19PubMed. Dysphotopsia after temporal versus superior laser peripheral iridotomy: a prospective randomized paired eye trial Holes at the top also carried more risk of dark shadow-type symptoms than holes at the side, with overall rates of about 11% versus 8%.20PubMed. Superior Laser Peripheral Iridotomy Confers Greater Risk of Negative Dysphotopsias than Temporal Laser Peripheral Iridotomy It is reasonable to ask your doctor where they plan to place the opening.
If you do notice something, a symptom that began right after the laser and sits in the same place each time may point toward the hole, though it isn’t proof on its own. Describing exactly when and where you see it, such as a line near bright lights or a shadow at one edge, helps your doctor decide whether it comes from the hole or from something else. Symptoms often fade as the brain adapts over weeks, and tinted or anti-glare glasses can help. If it persists, tell your doctor, because options exist.
Although the laser is fairly safe, it carries a long-term risk of damage to the cornea’s inner cell layer that can lead to a cloudy, swollen cornea.21PubMed Central. Effects of Laser Peripheral Iridotomy on Corneal Endothelial Cell Density and Cell Morphology in Primary Angle Closure Suspect Subjects This can appear as long as 8 years later and may need a corneal transplant.22PubMed Central. Effects of Laser Peripheral Iridotomy on Corneal Endothelial Cell Density and Cell Morphology in Primary Angle Closure Suspect Subjects
Cataract Surgery as an Alternative
In people with narrow angles and an early cataract, both the laser and cataract surgery widened the angle, but cataract surgery widened it more on every measure.23PubMed Central. Comparative study of the effects of laser peripheral iridotomy and cataract surgery on anterior chamber angle parameters in primary angle closure suspect patients The eye’s natural lens thickens with age and pushes the iris forward, and replacing it with a thin artificial lens makes room.
Even so, the laser is usually first. Many people with narrow angles have clear lenses, and taking out a clear lens is a bigger step. The laser is quick, done in the office, and low in cost, and lens surgery can come later if needed.
Cataract surgery is usually considered when the lens has clouded enough to affect daily vision, not just to open the angle. A doctor weighs the cataract’s effect on sight, how narrow the angle is, and the eye’s pressure. For someone who needs cataract surgery soon anyway, doing it first can handle both problems in one operation.
Useful questions for your doctor: Is my cataract affecting vision enough to justify surgery now? Would the laser buy time until lens surgery? What are the added risks of surgery compared with the laser? Will one eye or both need treatment?