Phakic intraocular lenses are lenses made of silicone or plastic permanently implanted into the eye without removing the eye’s natural lens.
They are approved by the FDA to correct nearsightedness (myopia) in people who don’t want to wear glasses or contact lenses. If the lenses are removed for any reason, the patient’s previous level of vision or condition of the eye cannot be guaranteed.
The difference between phakic intraocular lenses and intraocular lenses following cataract surgery is that phakic intraocular lenses are implanted without removing the natural lens and during cataract surgery the eye’s cloudy natural lens is removed.
A good candidate for phakic lenses is:
- Adult over the age of 21 and under the age of 45 years old because FDA approved lenses only for people over 21 and some phakic lenses have not been studied in patients over the age of 45,
- Person with refractive instability (who changed contact lenses or glasses prescription in the last 6 to 12 moths)
- Person who did not have an eye injury or previous eye surgery,
- Person who does not have a disease or are on medications that may affect wound healing like autoimmune disease and diabetes
- Person who do not actively participate in sports with a high risk of eye trauma
- Person who do not have large pupils and abnormal iris because there is a higher risk of experiencing visual disturbances after surgery that may affect ability to function comfortably or normally under such conditions (e.g., while driving at night)
- People who did not have uveitis (inflammation in the eye) and who do not have glaucoma.
Before surgery, the doctor will take a complete history about the patient’s medical and eye health and perform a thorough examination of both eyes, which will include measurements of pupils, anterior chamber depth (the distance between your cornea and iris), and endothelial cell counts (the number of cells on the back of your cornea).
Patient must tell the doctor about any allergies, taking any medication and having any medical condition. The doctor will give the patient instruction which medication he/she must or must not take prior to surgery (usually aspirin and anti-inflammatory medications because they can affect platelet and blood clotting).
One or two weeks before surgery, the doctor can schedule a patient for a laser iridotomy to prepare eyes for implantation of the phakic lens. During this procedure, which is performed in an office or clinic setting and takes few minutes, the doctor will numb the eye of the patient with drops.
Then, the doctor will rest a large lens on the eye and make a small hole in the extreme outer edge of the iris (the colored part of your eye) with a laser to prevent fluid buildup and pressure in the back chamber of the eye after phakic lens implantation surgery.
After this procedure, the doctor will after a few minutes check the eye pressure and the patient can go home. The doctor will decide if the patient can drive. The patient must for several days put the steroid drops into the eye to reduce inflammation from the procedure.
Some complications can occur like:
- Increase in eye pressure
- Cataract from the laser
- Bleeding into the anterior chamber of the eye (hyphema)
- Inflammation in the front part of the eye (iritis)
- Injury to the cornea from the laser that can result in clouding of the cornea
A few days before surgery, the doctor can prescribe to the patient antibiotic drops to prevent infection. The patient must arrange the transportation to and from surgery and must not eat or drink anything after midnight the night before surgery.
During the surgery which takes around 30 minutes, the patient must lie down on their back and remain still. The doctor will numb the eye with medication and also may give a patient a sedative or other medication to make him/her relax and injection around the eye to also prevent the patient from being able to move eye or see out of the eye.
An instrument called a lid speculum will be used to hold eyelids open. Then a doctor will insert the phakic lens through the incision in the eye into the anterior chamber, behind the cornea and in front of the iris.
The doctor will close the incision with tiny stitches, depending upon the type of incision, place some eye drops or ointment into the eye and cover your eye with a patch and/or a shield.
After the procedure, the patient will stay in the recovery room for a couple of hours before he/she will be allowed to go home. The patient will be given an Implant Identification card which he/she must keep and show to anyone who takes care of his/her eyes in the future.
Also, the patient will use antibiotic and anti-inflammatory drops at home as directed and pain medication can be prescribed if it is needed.
The day after surgery, the doctor will remove the patch and/or shield and will check the patient’s vision and the condition of the eye. Also, he/she will instruct the patient how and how long to use the eye drops prescribed after the surgery.
The doctor can tell the patient to continue wearing the shield all day and all night or just at night to prevent the patient from rubbing eye or putting pressure on the eye while sleeping and to protect the eye from accidentally being hit or poked while it is healing.
At first, the patient will return for additional follow-up visits every few days, then every few weeks and finally on a regular basis for the rest of the life.
The first few days after surgery, vision can be blurry or hazy but it will improve and stabilize usually in next 2 to 4 weeks. The patient can also experience sensitivity to light, glare, starbursts or halos around lights, or the whites of the eye may look red or bloodshot but these symptoms should decrease in next several weeks.
The potential risks are:
- Bleeding, or severe inflammation (pain, redness, and decreased vision)
- Loss of the vision
- Additional eye surgery to reposition,replace or remove the Phakic lens implant to improve the vision
- Developing debilitating visual symptoms like glare, halos, double vision
- Decreased vision in situations of low level lighting like driving
- Developing increased intraocular pressure
- Cataract or a retinal detachment
Phakic lenses are a new technology and have only recently been approved by the FDA so long-term data is not available.