Phototherapeutic Keratectomy (PTK) is a laser eye surgery that treats various conditions affecting the cornea, the clear, outermost layer of the eye. This procedure addresses corneal irregularities and opacities to improve the health and function of the corneal surface. PTK is distinct from vision correction surgeries like LASIK, as its primary goal is to resolve medical eye issues rather than refractive errors.
Understanding Phototherapeutic Keratectomy
Phototherapeutic Keratectomy uses an excimer laser, which emits ultraviolet (UV) light. This laser precisely removes microscopic layers of corneal tissue through a process called photoablation. Photoablation works by breaking molecular bonds within the tissue, allowing for the removal of affected cells without generating heat or causing thermal damage to the surrounding healthy cornea.
The main objective of PTK is to smooth the corneal surface by removing superficial irregularities, opacities, or lesions. This treatment promotes the regeneration of a healthier corneal epithelium, the eye’s outermost protective layer. By reshaping and smoothing the cornea, PTK can improve visual clarity and alleviate discomfort caused by various corneal disorders.
The PTK Procedure
The PTK surgical procedure begins with patient preparation, which typically involves the application of anesthetic eye drops to numb the eye. Patients are then positioned underneath the excimer laser system. A speculum holds the eyelids open and prevent blinking throughout the procedure.
During the laser application, the patient is asked to focus on a target light as the excimer laser delivers pulses of UV light, precisely removing the affected corneal tissue layer by layer. The surgeon may manually remove the outer corneal layer (epithelium) or use an alcohol solution to prepare the surface for laser penetration. A masking agent might also be applied to an irregular corneal surface to ensure a more uniform ablation. The laser treatment is quick, often taking less than a minute.
Conditions Treated by PTK
PTK is a treatment option for several specific corneal conditions that affect the surface and anterior layers of the eye. One common indication is recurrent corneal erosions (RCEs), a condition where the corneal epithelium repeatedly detaches from underlying tissue, causing pain and blurred vision. PTK addresses RCEs by smoothing the corneal surface and promoting stronger adhesion of the epithelium.
The procedure is also effective for certain types of corneal dystrophies, which are genetic conditions causing abnormal deposits or irregularities within the cornea. Examples include epithelial basement membrane dystrophy, granular dystrophy, and lattice dystrophy. Additionally, superficial corneal scars resulting from injuries or infections can be treated with PTK to enhance visual clarity. It is particularly suitable for opacities located in the anterior 10% to 20% of the cornea.
Recovery and Expected Outcomes
Following PTK surgery, patients can expect a recovery period during which the corneal epithelium heals and regenerates. Immediately after the procedure, a bandage contact lens is typically placed on the eye to provide comfort and protect the healing surface. Patients may experience temporary discomfort, such as mild pain, light sensitivity, tearing, and blurry vision for a few days to a week.
Post-operative care involves the regular use of prescribed medicated eye drops, including antibiotics to prevent infection and anti-inflammatory drops to manage swelling. Lubricating eye drops are also often used to alleviate dryness. The bandage contact lens is typically removed by the ophthalmologist after several days, once the new epithelial layer has formed. While initial visual improvement can be noticed within days, full recovery and stabilization of vision may take several weeks to months, depending on the individual and the treated condition.