Phototherapeutic keratectomy (PTK) is a laser eye procedure that treats conditions affecting the cornea, the transparent front surface of the eye. This outpatient procedure uses laser technology to reshape or remove microscopic layers of superficial corneal tissue. Its purpose is to address irregularities or opacities that impair vision and cause discomfort, aiming to restore a smoother, clearer corneal surface.
What is Phototherapeutic Keratectomy?
Phototherapeutic keratectomy uses an excimer laser to modify the cornea’s surface. This laser emits ultraviolet light at 193 nanometers, precisely removing microscopic layers of corneal tissue with minimal thermal damage. The procedure removes superficial corneal opacities, scars, or irregularities that interfere with light entering the eye.
By smoothing the corneal surface and creating a more uniform curvature, PTK improves visual acuity and alleviates symptoms such as glare or light sensitivity. It addresses conditions localized to the outermost layers of the cornea, typically affecting the epithelium and Bowman’s layer. The controlled tissue removal restores transparency and a regular shape to the corneal surface, enhancing the eye’s ability to focus light onto the retina.
Conditions Addressed by PTK
PTK treats superficial corneal disorders that affect vision or cause discomfort. These include:
- Recurrent corneal erosions: The laser removes the unstable epithelial layer, promoting healthier new cell growth and a smoother surface. This reduces the frequency and severity of painful erosions.
- Certain corneal dystrophies, such as epithelial basement membrane dystrophy (EBMD): PTK removes irregular cell deposits, improving vision and reducing symptoms like blurry vision or foreign body sensation.
- Superficial corneal scars from trauma or infection: Ablating scarred tissue restores corneal clarity and reduces visual distortion.
- Band keratopathy: The laser removes calcium deposits on the cornea, improving vision and appearance.
Determining Candidacy
Suitability for phototherapeutic keratectomy requires evaluation by an ophthalmologist. The nature and depth of the corneal condition are primary considerations, as PTK is most effective for superficial abnormalities. Deeper scars might require alternative surgical approaches. The eye’s overall health is assessed to ensure no underlying diseases could complicate the procedure or recovery.
Candidates should have good ocular health, free from active infections or severe dry eye syndrome. A thorough medical history identifies any systemic health issues that could affect healing. A detailed eye examination, including corneal topography and pachymetry, helps confirm PTK’s appropriateness for each individual’s corneal pathology and expected visual outcome.
The PTK Procedure
The phototherapeutic keratectomy procedure is typically performed in an outpatient setting and is relatively quick, usually lasting less than 30 minutes from start to finish. Patients receive topical anesthetic eye drops to numb the eye, ensuring comfort throughout the process. A speculum is then gently placed to keep the eyelids open and prevent blinking during the laser application, allowing for an unobstructed view of the cornea. The surgeon may then gently debride, or remove, the outermost layer of the corneal epithelium if necessary, to expose the underlying affected tissue for direct laser treatment.
Once the eye is prepared and properly positioned, the patient is asked to focus on a target light while the excimer laser delivers precise pulses of ultraviolet light. This computer-guided laser ablates the targeted corneal tissue, layer by layer, according to a pre-programmed pattern designed to remove irregularities or opacities with micron-level precision. The actual laser application usually takes only a few minutes, depending on the size and depth of the area being treated. After the laser treatment is complete, a bandage contact lens is often placed on the eye to protect the healing surface, reduce discomfort, and promote proper re-epithelialization during the initial recovery period.
Recovery and Post-Procedure Care
Following phototherapeutic keratectomy, patients typically experience some immediate sensations such as mild to moderate discomfort, a foreign body sensation, and light sensitivity. These symptoms are common as the corneal surface begins to heal. A bandage contact lens, applied at the end of the procedure, helps to alleviate these sensations and protect the newly treated area. This lens usually remains in place for several days until the corneal epithelium has fully regenerated.
Patients are prescribed a regimen of eye drops, which typically includes antibiotics to prevent infection and anti-inflammatory drops to manage swelling and discomfort. Strict adherence to this medication schedule is important for optimal healing. Vision may be blurry for a few days to weeks, gradually improving as the cornea heals and reshapes. Full visual recovery can take several weeks to a few months, depending on the individual and the extent of the treatment.
During the recovery period, it is important to avoid rubbing the treated eye to prevent dislodging the bandage lens or damaging the healing tissue. Strenuous activities, heavy lifting, and swimming should be avoided for at least one to two weeks to reduce the risk of complications. Temporary side effects like glare or halos, particularly at night, may occur but usually diminish over time. Patients should contact their ophthalmologist immediately if they experience sudden severe pain, worsening vision, or signs of infection such as increased redness or discharge.