What is Phototherapeutic Keratectomy?

Phototherapeutic keratectomy or PTK is a procedure used to correct different corneal diseases. This surgical technique uses UV light and laser technology to reshape and restore the cornea. Patients with corneal diseases such as scars, degenerations, dystrophies, bullous keratopathy, and band-shaped keratopathy which are important causes of visual blindness, are considered for this Phototherapeutic keratectomy or PTK.

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Phototherapeutic keratectomy or PTK is performed with an excimer laser and works on the principle of photoablation, by breaking the bonds between molecules. You can expect your vision to improve gradually and usually be good enough to allow you to drive a car within 1 to 2 weeks following surgery. However, your best vision may take some time from 6 weeks up to 6 months. This is a safe and effective procedure in the management of superficial corneal diseases such as corneal scars, degenerations, and dystrophies. Phototherapeutic keratectomy or PTK surgery has a success rate of over 90%.

Phototherapeutic keratectomy or PTK is a procedure used to correct different corneal diseases. This surgical technique uses UV light and laser technology to reshape and restore the cornea. Phototherapeutic keratectomy or PTK has been used to treat scars, recurrent erosions, and different corneal dystrophies. Phototherapeutic keratectomy or PTK mostly helps delay or postpone corneal grafting or replacement in the patient. It is considered to be a bridge between medical and surgical management of various corneal disorders.

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Why is Phototherapeutic Keratectomy Beneficial?

To understand the benefits of phototherapeutic keratectomy, we have to understand the importance of cornea first. Cornea is the outermost layer of the eye and acts like a window that lets the light into the eye. The cornea acts as a barrier against substances like dirt, germs, and other particles that are harmful for the eyes. Cornea also helps in vision by helping focus the light that comes into the eyes and is responsible for 65-75% of the eye’s total focusing power. Corneal disorders greatly affect the vision and it becomes important to improvise the vision. Phototherapeutic keratectomy or PTK has been found to be an effective treatment for many superficial corneal disorders. It can also be combined with other surgeries like PRK (photorefractive keratectomy). A combination of PRK and PTK is effective in the alleviation of symptoms and prevention of recurrences of corneal erosion.

Who is a Suitable Candidate for Phototherapeutic Keratectomy?

Patients with corneal diseases such as scars (caused by injury to the cornea), degenerations (corneal thinning), dystrophies (deposition of materials in cornea), bullous keratopathy (bullae or vesicles formation in the cornea), and band-shaped keratopathy (deposition of calcium salts) which are important causes of visual blindness, are considered for Phototherapeutic keratectomy or PTK surgery. The key to a successful surgery is selection of a suitable candidate. The selection depends on many factors like if the patient has diabetes or rheumatoid arthritis, they may have a delayed epithelial healing. Selection also depends on corneal disease pathology, whether it is progressive (dystrophy) or non-progressive (scar). It also depends on associated symptoms of pain, watering, foreign body sensation and preoperative refractive errors.

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The best candidates for Phototherapeutic keratectomy or PTK surgery are patients with opacities in the anterior 10 – 20% of the cornea, without significant irregularity and thinning.

Systemic diseases such as diabetes mellitus and autoimmune disorders are contraindications for Phototherapeutic keratectomy or PTK.

Evaluations Done Before Phototherapeutic Keratectomy

The main diagnosis and planning of phototherapeutic keratectomy is based on clinical judgment, on slit-lamp examination, and the amount of refractive error. Some imaging studies are performed to manage and plan the postoperative outcome. These are corneal topography, which helps in planning and following up of patients after Phototherapeutic keratectomy. Ultrasound biomicroscopy, determines the extent of corneal pathology. Ocular coherence tomography is also performed before the Phototherapeutic keratectomy or PTK surgery and is used to measure the depth of opacities in the cornea and helps in the planning of either a lamellar or a penetrating procedure depending on the depth of the opacities.

How is Phototherapeutic Keratectomy Performed?

Phototherapeutic keratectomy or PTK surgery is performed with an excimer laser and works on the principle of photoablation, by breaking the bonds between molecules. This is an athermal process and works with submicroscopic precision with minimal damage to adjacent tissues. Phototherapeutic keratectomy or PTK surgery allows the removal of superficial corneal opacities and surface irregularities. The laser energy destroys intermolecular bonds in the corneal tissue resulting in tissue removal by a process termed “photoablative decomposition”. The exquisite precision with which the tissue can be removed, and the absence of thermal damage, render this laser suitable for surgery on the delicate cornea.

Phototherapeutic keratectomy or PTK procedure is generally done under topical anesthesia. Strict aseptic conditions are maintained throughout the surgery. In cases where PTK is combined with other surgeries or while dealing with pediatric patients, general anesthesia is used. In Phototherapeutic keratectomy or PTK surgery, the epithelium is removed using an alcohol solution; the excimer laser is applied to the eye removing a thin layer. Theoretically, this provides a more sound base layer for healing of the erosion, allowing the corneal epithelium cells to heal all in one sheet, making the healing process more complete over the entire surface. After the Phototherapeutic keratectomy or PTK surgery, a contact lens bandage is put in place to provide a healing environment and reduce pain. You will also be prescribed a regimen of antibiotic, steroid eye drops as well as moisturizing eye drops. It is important that the patient adhere to regimen as these medicines will help the patient’s eye heal and relieve any discomfort.

Recovery after Phototherapeutic Keratectomy or PTK Surgery

Post Phototherapeutic keratectomy, the first priority is to heal the eyes and usually a bandage contact lens is worn for several days. You will be expected to visit the doctor within the first 1-3 days for the follow up. The bandage contact lens is removed once the surface of the eye is healed. The vision may be clear and blurry for the initial few days following the surgery. Eyes may feel dry and you will be given prescription to avoid any kind of infection and to keep the eyes moist.

You can expect your vision to improve gradually and usually be good enough to allow you to drive a car within 1 to 2 weeks following Phototherapeutic keratectomy or PTK surgery. You must keep in mind that your best vision may take even more time, approximately 6 weeks to 6 months following Phototherapeutic keratectomy or PTK surgery.

Complications of Phototherapeutic Keratectomy

  1. Recurrence of primary disease
  2. Infection
  3. Reactivation of herpes simplex virus
  4. Delayed healing of epithelium
  5. Corneal opacity and scarring
  6. Allograft transplant rejection

Conclusion

Phototherapeutic keratectomy is a safe and effective procedure in the management of superficial corneal diseases such as corneal scars, degenerations, and dystrophies. It significantly reduces recurrent corneal erosions and improves visions. It reduces recurrent corneal erosions and improves vision. Phototherapeutic keratectomy or PTK surgery has a success rate of over 90%.

Pramod Kerkar

Written, Edited or Reviewed By:

, MD,FFARCSI

Pain Assist Inc.

Last Modified On: February 15, 2019

This article does not provide medical advice. See disclaimer

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