Consultation for Pi in Eye Surgery
Pi in Eye Surgery: Basic Description
By Rajesh Khanna, MD
The Pi in eye surgery consists of interchanging the natural lens of the eye with a Presbyopic implant (Pi) lens. For this surgery there are a assortment of lenses that can be inserted into the eye including: Restor, Tecnis and Crystalens. A consultation will help the patient and doctor choose the suitable lens that best fits the specific needs of the individual.
Pi in Eye Consultation: What to Expect
Pi in eye surgery requires a consultation with the doctor is required so one can learn all about the surgery and also select the specific lens to be planted into the eye based on individual needs. The consultation also permits the patient to become comfortable with the process and to create a relationship with the doctor and staff. Every bit as essential, it will enable the surgeon to guarantee the person is a great candidate. In general, many surgeons like to conduct a comprehensive examination themselves. The doctor will evaluate the medical and vision history, dilate the eyes and do diagnostic tests on the eyes. Specific vision needs and lifestyle preferences will be learned during the consultation. Many surgeons will show pictures or videos of the actual procedure so that patients can fully comprehend what they will be happening to their eyes. Patients may also be given the opportunity to talk with former patients who have previously had the pi in eye surgery.
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Note that you may be asked for information involving: past/present eye problems, injuries or surgeries, medical conditions and medications, family history and primary care physician’s information. As well, you will need to bring your glasses and/or contact lenses to the consult. It is also wise to bring sunglasses in case the doctor dilates your pupils. Enlarged pupils enhances sensitivity to light as well as causes blurry vision for a couple hours.
Pi in Eye Consultation: Vision Tests
On the day of your Pi in Eye examination, the surgeon will use different tests to make sure that your eyes are healthy and in good condition for surgery. The doctor checks for many conditions such as: myopia (nearsightedness), hyperopia (farsightedness), Presbyopia, Glaucoma, Cataracts, and History of dry eyes. The exam will start with the doctor or assistant using familiar Snellen chart which included a series of black letters that vary from big to small font. The results from this are expressed as for example 20/20 or 20/40. The first number expresses the fixed distance of twenty feet at which the test is conducted, while the second number is the distance from which a person with clear vision can see the same letter from. For instance, if your visual sight is at 20/40, then what you are seeing at twenty feet a person with perfect vision can see at forty feet. While if you are 20/80 your vision is one-fourth as good as normal and at 20/200 a person is considered legally blind.
Some tests your doctor may perform during the Consultation for Pi in Eye surgery:
- Measures length & shape of eye using machine called IOL Master or Lenstar
- Use an ultrasound or high frequency sound waves to measure the length of the eye. This is similar to the sonar system used by bats.
- Measures the thickness of the cornea and detects abnormal corneas.
- Uses ultrasound or non-contact optical method.
- A print out with the approximate prescription is generated.
- Then a phoropter, which has a range of lenses, is employed and your doctor will obtain the best correction and prescription for you.
- Provides a color map displaying the shape and power of the cornea.
- Detects astigmatism and reveals any distortions or abnormal shape.
Intra-ocular Pressure Measurement:
- Measures pressure inside your eye. This aids the doctor in determining if any sign of glaucoma exists.
Iris Pupil Examination:
- Checks for irregularities with the pupil and whether it responds correctly to light.
- Helps detect any optic nerve issues.
- Gives wider view of the inside of your eyes to visualize the retina, blood vessels, & optic nerves.
- Helps detect hypertension, diabetes and various other pathology.
- Instrument used to inspect any blood vessels or optic nerves at the back of the eye.
- High blood pressure, diabetes, and some other diseases can be detected from this exam.
- The slit-lamp flashes slits of light on the eye showing the doctor any diseases.
- The presence of cataract formation can be detected.
Visual Field Measurement:
- This measures how far you can see to the right and left and how well you see out of the corner of your eye (peripheral vision).
- Contrast Sensitivity Testing:
- Checks for the ability to detect between light and dark
Ocular Coherence Tomography (OCT):
- Uses infrared light and interferometry to obtain detailed scans of various parts of the eye including the cornea and retina
Calculations bases on visual tests:
All these measurements will be used determine the best power of the intraocular lens (IOL) to be embedded. The surgeon will use mathematical formulas employed to generate the lens power. The formulas are called: Hoffer Q, SRKT, Holladay 2, and Haigis. A physician may compare calculation results with different formulas. The physician can then fine-tune results based on the outcome of previous results. Figures after previous eye surgery is more difficult as the assumptions made in the formula are changed. Furthermore, after previous Lasik the relation between anterior and posterior cornea is changed. Radial Keratotomy interferes in corneal power detection as well. Certain calculations are necessary on these particular cases.
This is for educative purposes. Dr. Khanna is available for Consultation for Pi in Eye surgery in Beverly hills and Westlake Village. He is a member of American Society of Cataract and Refractive Surgery.