lasers in ophthalmology

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“Lasers in ophthalmology” spans several distinct procedures. Key areas are:

Retinal photocoagulation - diabetic retinopathy, retinal tears, vein occlusion
YAG laser - posterior capsulotomy and peripheral iridotomy
Glaucoma lasers - SLT, ALT, cyclophotocoagulation
Refractive corneal lasers - LASIK, PRK, SMILE
Other anterior-segment uses - Nd:YAG membranectomy, laser for ROP, etc.

At a high level, lasers deliver wavelength-specific energy to cut, photodisrupt, coagulate, or remodel ocular tissue. The choice depends on the target tissue and indication.

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“Lasers in ophthalmology” spans several distinct procedures. Key areas are:

Retinal photocoagulation - diabetic retinopathy, retinal tears, vein occlusion
YAG laser - posterior capsulotomy and peripheral iridotomy
Glaucoma lasers - SLT, ALT, cyclophotocoagulation
Refractive corneal lasers - LASIK, PRK, SMILE
Other anterior-segment uses - Nd:YAG membranectomy, laser for ROP, etc.

At a high level, lasers deliver wavelength-specific energy to cut, photodisrupt, coagulate, or remodel ocular tissue. The choice depends on the target tissue and indication.

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ophthalmic lasers

Lasers in ophthalmology: topic map

Basic principles
- Laser-tissue interactions: photocoagulation, photodisruption, photoablation, and photoselective effects
- Common lasers: argon, diode, frequency-doubled Nd:YAG 532 nm, Nd:YAG 1064 nm, excimer 193 nm, femtosecond laser
Retinal lasers
- Panretinal photocoagulation for proliferative diabetic retinopathy
- Focal/grid or micropulse treatment for selected macular disease
- Barrage laser retinopexy for retinal breaks and lattice degeneration
- Use in retinal vein occlusion and retinopathy of prematurity
Nd:YAG laser
- Posterior capsulotomy for posterior capsular opacification after cataract surgery
- Peripheral iridotomy for angle-closure mechanisms
- Potential complications such as transient intraocular-pressure rise, inflammation, IOL pitting, retinal tear, and macular edema
Glaucoma lasers
- Selective laser trabeculoplasty (SLT)
- Argon laser trabeculoplasty (ALT)
- Laser peripheral iridotomy
- Cyclophotocoagulation for refractory glaucoma
Corneal and refractive lasers
- PRK, LASIK, femtosecond LASIK, SMILE
- Excimer laser reshapes corneal stroma; femtosecond laser creates a flap or lenticule
- Important complications: dry eye, glare/halos, ectasia, infection, haze, undercorrection or overcorrection
Other applications
- Laser treatment of iris lesions and pupillary membranes
- Cyclodestructive procedures
- Oculoplastic and vascular applications in selected settings

High-level overview

Ophthalmic lasers act by delivering controlled energy at a chosen wavelength to a precise ocular target. Their effects differ:

Photocoagulation: thermal burn that seals or destroys tissue, such as retinal laser for neovascularization or retinal tears.
Photodisruption: shock-wave tissue disruption, as with Nd:YAG posterior capsulotomy.
Photoablation: removal of microscopic amounts of tissue, as with excimer laser refractive surgery.
Photoselective trabecular treatment: targets pigmented trabecular-meshwork cells to lower intraocular pressure, as in SLT.

The main safety principle is to match the laser type, energy, spot size, duration, and target location to the indication, while monitoring for inflammation, pressure elevation, retinal injury, and visual symptoms.

Which section would you like as a detailed exam note: retinal lasers, Nd:YAG and glaucoma lasers, refractive lasers, or the complete concise overview?

yag laser

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Nd:YAG capsulotomy

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AAO Nd:YAG laser posterior capsulotomy peripheral iridotomy patient safety

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Nd:YAG laser posterior capsulotomy diagram ophthalmology

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https://www.aao.org/education/clinical-statement/laser-surge…

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Nd:YAG capsulotomy complications

Nd:YAG laser in ophthalmology

Nd:YAG means neodymium-doped yttrium-aluminium-garnet laser. In ophthalmology, it usually operates at 1064 nm in a pulsed, Q-switched mode.

Mechanism: photodisruption

It produces a highly focused plasma and shock wave at the focal point, causing mechanical disruption of tissue rather than thermal coagulation.

This differs from:

Argon/diode/532 nm lasers: mainly photocoagulation
Excimer laser: photoablation of cornea
Nd:YAG laser: photodisruption

Main uses

1. Nd:YAG posterior capsulotomy

Indication: visually significant posterior capsular opacification (PCO) after extracapsular cataract extraction or phacoemulsification with posterior chamber IOL implantation.

PCO is due to residual lens epithelial-cell proliferation or fibrosis on the posterior capsule, causing gradual blurring, glare, reduced contrast, and reduced visual acuity.

Procedure principle: a central opening is created in the opaque posterior capsule, restoring the visual axis. It is indicated when PCO impairs vision or functional activities, not merely because opacity is seen on examination.

Complications

Transient rise in intraocular pressure
Anterior uveitis
IOL pitting
Cystoid macular edema
Retinal tear or retinal detachment, especially in predisposed eyes such as high myopia
Rarely, damage to cornea or vitreous-related problems

A recent systematic review on central macular thickness after Nd:YAG capsulotomy is indexed as PMID 42553481; it does not change the standard indication or need for post-procedure surveillance.

2. Nd:YAG peripheral iridotomy (LPI)

Indication: prevention or treatment of pupillary-block angle closure, including:

Acute angle-closure glaucoma, once corneal clarity permits
Primary angle closure or primary angle-closure suspect with an occludable angle
Fellow eye of a patient with acute primary angle closure
Iris bombe from posterior synechiae
Some cases of secondary pupillary block

Principle: a small full-thickness hole in the peripheral iris connects the posterior and anterior chambers. This bypasses pupillary block, equalizes pressure across the iris, and relieves iris bombe.

Kanski describes the purpose as re-establishing communication between the posterior and anterior chambers in pupillary-block angle-closure glaucoma. It also cautions that iridotomy alone may not normalize IOP where extensive peripheral anterior synechiae have already compromised the angle. Kanski's Clinical Ophthalmology: A Systematic Approach, 10th ed.

Complications

Transient IOP spike
Mild anterior chamber inflammation
Iris bleeding
Corneal endothelial injury
Closure or inadequate patency of the iridotomy
Dysphotopsia or ghost images
Rare retinal injury

The Wills Eye Manual advises baseline gonioscopy, IOP-lowering pretreatment in appropriate cases, and attention to iridotomy location because dysphotopsias can occur. The Wills Eye Manual, p. 1136.

3. Other selected uses

Membranectomy/synechiolysis: opening certain pupillary or anterior segment membranes
Anterior hyaloidotomy with posterior capsulotomy: selected pseudophakic cases of aqueous misdirection (malignant glaucoma)
Release of selected iris-IOL adhesions in specialist settings

Key examination comparison

Feature	Nd:YAG laser	Argon laser
Main effect	Photodisruption	Photocoagulation
Wavelength	1064 nm	Blue-green wavelengths
Tissue action	Plasma formation and shock wave	Thermal tissue coagulation
Classic use	Capsulotomy, peripheral iridotomy	Retinal photocoagulation, iridoplasty
Incision required	No	No

One-line viva answers

Laser used for PCO: Nd:YAG laser.
Procedure for PCO: Nd:YAG posterior capsulotomy.
Laser action: photodisruption.
Laser used in pupillary-block angle closure: Nd:YAG peripheral iridotomy, sometimes preceded or assisted by argon laser in thick/dark irides.
Important immediate complication: transient rise in IOP.
Important late retinal complication after capsulotomy: retinal tear or detachment.

The AAO laser-surgery statement lists peripheral iridotomy and posterior capsulotomy among accepted ophthalmic Nd:YAG laser procedures and emphasizes that laser procedures can cause significant ocular injury if improperly performed.

refractive surgeries types in short

Types of refractive surgery

1. Corneal laser procedures

PRK: Surface epithelium removed; excimer laser reshapes cornea.
LASIK: Corneal flap created, then excimer laser reshapes stromal bed.
Femto-LASIK: Femtosecond laser creates flap, excimer laser corrects power.
SMILE: Femtosecond laser creates and removes a stromal lenticule through a small incision.
LASEK / Epi-LASIK: Surface-ablation variants, less commonly used.

2. Lens-based procedures

Phakic IOL (ICL): An artificial lens implanted without removing natural lens, useful in high myopia.
Refractive lens exchange (clear-lens extraction): Natural lens removed and replaced with an IOL, commonly for high refractive error or presbyopia.

3. Incisional procedures

Radial keratotomy (RK): Radial corneal cuts for myopia. Now largely obsolete.
Astigmatic keratotomy / limbal relaxing incisions: Corneal incisions to reduce astigmatism.

4. Other

Corneal inlays: For presbyopia; now rarely used.
Conductive keratoplasty: Radiofrequency corneal steepening for presbyopia/hyperopia; rarely used.

PRK: Surface epithelium removed; excimer laser reshapes cornea. LASIK: Corneal flap created, then excimer laser reshapes stromal bed. Femto-LASIK: Femtosecond laser creates flap, excimer laser corrects power. SMILE: Femtosecond laser creates and removes a stromal lenticule through a small incision. LASEK / Epi-LASIK: Surface-ablation variants, less commonly used.

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PRK LASIK SMILE

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American Academy Ophthalmology PRK LASIK SMILE refractive surgery overview

Your list is correct. A cleaner short exam version:

PRK: Corneal epithelium is removed and an excimer laser ablates the anterior corneal stroma to reshape the cornea.
LASIK: A corneal flap is created, lifted, and an excimer laser reshapes the underlying stroma.
Femto-LASIK: LASIK in which the flap is created with a femtosecond laser instead of a microkeratome.
SMILE: A femtosecond laser creates an intrastromal lenticule, which is removed through a small corneal incision. No flap is made.
LASEK / Epi-LASIK: Surface-ablation procedures in which the epithelium is loosened or separated and excimer laser ablation is performed.

Memory aid:
PRK = surface, LASIK = flap, Femto-LASIK = laser flap, SMILE = lenticule through small incision.

Kanski describes PRK as excimer-laser surface ablation and SMILE as femtosecond creation and removal of a corneal lenticule. Kanski's Clinical Ophthalmology: A Systematic Approach, 10th ed. The AAO refractive-surgery overview lists LASIK, PRK, and SMILE as common procedures.

summerise in short differences and complicarion

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