What Is Phototherapeutic Keratectomy?
Phototherapeutic keratectomy (PTK) is a procedure that corrects surface-level corneal diseases, abnormalities, and visual opacity (cloudiness). The cornea is the clear, outermost layer of your eye through which light is focused.
A minimally invasive surgery, PTK uses excimer lasers of high-energy ultraviolet (UV) light radiation to remove affected corneal tissue. The excimer laser can treat abnormal tissue with extreme precision, causing little to no thermal damage to nearby tissues.
PTK isn't the same as laser in situ keratomileusis (LASIK), even though both procedures involve the use of excimer lasers. LASIK corrects a person’s vision by changing the shape of the cornea, which in turn changes the way that light refracts off the eye. PTK removes abnormalities from the corneal surface and cloudiness from your vision.
Conditions we treat with phototherapeutic keratectomy
PTK can be used to correct many corneal diseases and problems, including:
- Bullous keratopathy (BSK) — Occurs when bullae (blisters) form and burst on the cornea of the eye. BSK can cause eye pain, excessive tearing, and a feeling of foreign matter or irritation in the eye. PTK, particularly deeper ablations, can alleviate pain, enhance vision, and relieve symptoms associated with BSK.
- Dystrophies — PTK offers relief for people with various corneal dystrophies, such as anterior basement membrane dystrophy and stromal dystrophy. It can also improve vision for those with corneal scars from eye injuries, trauma, surgery, or infections.
- Keratitis —Refers to inflammation of the cornea, often caused by infections related to contact lens wear. PTK helps sterilize the cornea and eliminate the microbes responsible for the infection.
- Keratoconus — When the cornea thins out and bulges like a cone. Certain people with keratoconus can develop anterior stromal scarring that forms a nodule that affects contact lens tolerance. PTK can help remove these nodules.
- Recurrent corneal erosions (RCEs) — Typically arise due to corneal injury, epithelial basement membrane dystrophy, or spontaneous occurrences.
- Salzmann nodular degeneration (SND) — Refers to the formation of bluish-white nodules at the periphery of the cornea. SND can lead to tear film abnormalities, irregular astigmatism, and difficulties with contact lens use.
- Scars — Due to corneal injury or surgical complications following PRK or LASIK.
- Spheroidal degeneration — Refers to the appearance of the sub-epithelial layer, Bowman’s membrane, or superficial stroma of the cornea in two distinct forms: Smooth, gelatinous, and yellow, in which the affected areas exhibit a smooth, yellow appearance; and irregular, raised, with yellow color, which can manifest as irregular, raised yellow patches. Symptoms associated with spheroidal degeneration include vision disturbances, eye pain, sensitivity to light, and an increased susceptibility to corneal infections. PTK can create a smoother corneal surface, helping alleviate these symptoms.
Why Would I Need Phototherapeutic Keratectomy?
Phototherapeutic keratectomy helps smooth the corneal surface, remove scar tissue, and make vision clearer in instances of corneal trauma, infection, or scarring. If left untreated, some corneal diseases can lead to blindness.
Is phototherapeutic keratectomy right for me?
The best candidates for phototherapeutic keratectomy are those with opacities (lack of normal transparency) in the anterior 10% to 20% of the cornea or superficial stromal lesions (the area behind the epithelium).
Your doctor will perform a slit lamp examination similar to an ordinary eye exam and consider the degree of existing refractive error (how well/clearly you see) before planning your PTK treatment.
PTK may not be right for you if you have:
- Deeper corneal scars or lesions.
- Diabetes or an autoimmune disorder.
- Suffered a corneal infection in the last six months.
What Are the Risks and Complications of Phototherapeutic Keratectomy
Certain complications may arise following a phototherapeutic keratectomy procedure.
The most common are:
- Changes in vision due to refractive errors.
- Corneal opacity and scarring.
- Infection at the site of the procedure.
- Infectious keratitis may recur.
- Reactivation of herpes simplex virus.
- Recurrence of dystrophies of the Bowman’s layer and stroma.
- Return of primary corneal opacity or haze.
- Slow-healing epithelium, especially if you have diabetes or an autoimmune disorder.
- Corneal transplant rejection.
In addition, PTK sometimes needs to be repeated to achieve the desired effect.
What Should I Expect From Phototherapeutic Keratectomy?
Before: How to prepare for your PTK
Before your doctor schedules your corneal transplant, they'll conduct an extensive eye exam and measure your eye.
Tell your doctor what prescription and over-the-counter (OTC) medications, herbs, and supplements you take and what health issues you have. Also, tell your doctor about any allergies you have, especially to medications or latex.
Instructions include:
- Arranging a ride home after the surgery, as you can't drive home yourself.
- Arriving for surgery without makeup, creams, or lotions on your face.
- Wearing comfortable clothing on the day of surgery.
During your PTK
The procedure is performed most often while you're under topical anesthesia, where the surface of the affected area is numbed with eye drops.
During the procedure:
- Using a hockey stick-shaped instrument, the damaged tissue is removed with the epithelium (the layer of cells covering the cornea).
- Once the tissue has been removed, the excimer laser is used to ablate (surgically remove) any abnormalities affecting the deeper tissue beneath the epithelium. The removal of the damaged tissue allows new epithelial tissue to grow in a smoother fashion.
- Your doctor will examine your eye using a slit lamp, similar to that used in an ordinary eye exam, to ensure that they do not over-ablate certain areas and to see whether any damaged tissue remains.
- Your doctor will determine the ablation rate (the amount of tissue removed) and, therefore, the technique of PTK to use based on the type of disease and the depth, size, and site of the corneal abnormality.
Recovery after PTK
While the procedure itself will not be painful, your eyes may be sore for a couple of days following PTK. Your doctor may prescribe an oral pain medication for you to take to manage your post-surgery pain.
In addition:
Your doctor may use certain imaging techniques following PTK to manage your post-surgery outcome.
These techniques may include:
- Corneal topography — A painless imaging method that creates a detailed map of the cornea’s curvature and shape. This information is crucial for diagnosing and managing eye conditions. By analyzing the visual map, eye specialists can assess irregular astigmatism, detect disorders like keratoconus, and plan treatments such as LASIK or contact lens fitting.
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Optical coherence tomography (OCT) — A noninvasive imaging technique used to generate detailed cross-sectional pictures of the retina by using light waves. With OCT, your ophthalmologist can visualize distinct layers of the retina, measure their thickness, and diagnose conditions such as glaucoma, age-related macular degeneration (AMD), and diabetic eye disease. There’s also a related method called optical coherence tomography angiography (OCTA), which captures images of blood vessels in and under the retina without using dye.
- Ultrasound biomicroscopy (UBM) — A painless imaging method that creates detailed cross-sectional images of the eye’s anterior segment, including the cornea, iris, ciliary body, and anterior chamber angle. High-frequency ultrasound waves are employed to visualize these structures accurately.
What is the success rate of phototherapeutic keratectomy?
The outcome of phototherapeutic keratectomy varies based on the type and severity of preexisting corneal disease. Overall, the goal of treatment is to reduce or improve symptoms and improve the clarity of your vision.
If a significant amount of corneal tissue must be removed, PTK can sometimes result in induced refractive errors (vision problems), making it more difficult to clearly see far away objects. However, PTK can improve best corrected visual acuity or vision with corrective lenses.
By UPMC Editorial Staff. Last reviewed on 2025-01-30 by .
