Here’s what to expect when you come to LA Sight for your cataract evaluation. We perform a variety of special tests designed to evaluate your candidacy. Many prospective clients are impressed by the ease, elegance and sophistication of the process. We firmly believe that careful, meticulous evaluations contribute to great results. Fees do apply for lens-based surgical care and are typically covered by health insurance, assuming you have a PPO or POS plan.
The preliminary testing typically takes about 20 to 30 minutes. When this is complete, you will meet Dr. Wallace to review the results, discuss your options, and have all your questions addressed.
Based upon the above information, our staff and Dr. Wallace will be able to advise you about your candidacy for cataract and IOL care. For those that choose to proceed with surgical corrective care, we perform more extensive testing as follows:
What These Tests Measure, and Why They’re Important:
General Health Review: Cataract and IOL care is extremely safe, performed on an outpatient basis under “twilight” anesthesia (IV sedation monitored by an anesthesiologist) with numbing eye drops. We do need to know about your general health, medications you take, allergies to medications if any, prior surgery you may have had, and related health matters.
Eye Health Assessment: It should be self-evident that healthy eyes, eyelids, ocular surface and related structures are a prerequisite to any contemplated elective eye surgery.
|Automated Refraction, Topography and Wavefront Analysis: Using infrared sensors and auto-focus technology, autorefractors are able to measure the optical state of the eye, (nearsightedness, farsightedness, astigmatism) called the refraction. While very accurate, the readings are not always perfect, so the process of ‘subjective refraction’ (having the examiner ask “Which is better, one or two?”) is still performed to fine-tune the measurements. In the near future, wavefront analysis may replace even this time-honored method of measuring the prescriptive needs for optimum vision.
|Biometry: The determination of the prescription power necessary to correct your vision to its optimal level with a lens implant depends on accurate measurement of the internal dimensions of the eye. This is now done with a laser range-finder type instrument called an optical interferometer. It measures the ocular axial length (distance from cornea to retina), anterior chamber depth (distance from cornea to front of the natural crystalline lens), corneal curvature, and corneal diameter. These measurements are then entered into a series of equations to determine the prescription of the IOL – a process called IOL power calculation. We use an instrument called the Zeiss IOL Master for this purpose
|Galilei Corneal Imaging. This sophisticated instrument measures corneal topography of both front and back corneal surfaces, and maps corneal thickness across the entire surface.The cornea accounts for about 65% of the eyes’ focusing power. In the normal case, corneal curvature is smooth, symmetric, and regular in contour. However, certain conditions are associated with irregularity, distortion, or significant asymmetry of corneal curvature. Examples include keratoconus, a disorder characterized by abnormal thinning of the cornea, with distortion and irregular, abnormally steep curvature over the area of thinning. In cases of topographic asymmetry, optical distortion from the cornea can’t be corrected by cataract and IOL care, so expectations must be adjusted.
|Prescription Analysis: Modern instruments called lens analyzers can measure the existing prescription in your current eyeglasses. It is helpful to know this information, even if your glasses are several years old. By comparing the prescription in the existing glasses to the current one measured at the time of consultation, we know if there has been any change in the prescription over time; and we also know by how much the prescription has changed.
|Subjective Refraction: The process of measuring and fine-tuning the prescription measurement. Typically a person sits behind an instrument containing many types of lenses (a phoropter) and the examiner carefully adjusts the combination of lenses to optimize vision clarity. This is a subjective, interactive process where feedback is essential (but often boring), which is why the examiner will ask, “Which is better, one or two?”
|Slit-Lamp Microscopy : The eyelids and eyes are examined in high magnification using a special microscope with a slit-shaped beam. This affords a close-up view of the eyelids, conjunctiva (inside lining of the lids and membrane covering the sclera), cornea, sclera, iris, anterior chamber, pupil, lens, and anterior vitreous. Eye pressure can also be measured with a tonometer attached to the slit-lamp microscope.
|Tonometry: Measurement of eye pressure is performed as a screening test to aid in the detection of glaucoma. Elevation of eye pressure is one of the major risk factors in this condition. Dr. Wallace is a recognized authority on the measurement of eye pressure, being one of the inventors and developers of the Tono-Pen tonometer, one of the two most popular instruments for measuring eye pressure in the world today.
|OCT – Optical Coherence Tomography – A high-resolution scan that can image the central retina and optic nerve in microscopic detail. This can be done either as a screening test, to establish the microscopic integrity and health of the macula (central retina), or to investigate possible retinal causes of imperfect, distorted or unclear vision. We want to make sure that the retinas are healthy before performing cataract surgery — if the film in the camera is bad, changing the lens probably won’t help! If certain retinal conditions are present (macular swelling, wrinkling, etc.) then some potential benefits of lifestyle IOLs may not be attainable.