Refractive Cataract Surgery Suitability Screening Instructions
Contact Lens Holiday
Soft contact lens (SCL) users are required to discontinue the use of SCLs for at least 1 week prior to the refractive cataract surgery suitability screening (screening). Hard contact lens and Rigid Gas Permeable (RGP) users are required to discontinue the use of RGPs for at least 4 weeks prior to the screening. Contact lens holidays allow the surface of the cornea to recover to its natural state, thereby increasing the reliability of the results of the screening. Kindly wear your prescription eye glasses during this contact lens holiday. Please coordinate closely with our staff if you wish to move the tests to an earlier or later date.
Kindly apply over-the-counter preservative-free lubricating drops hourly to both eyes during waking hours for at least 1 week prior to the surgery. This will make you feel comfortable with instilling topical medication to your eyes after surgery.
Refractive Cataract Surgery Suitability Screening
After complying with your refractive cataract surgery pre-screening instructions, you are now ready to proceed with your screening. It usually takes an average of three (3) hours to complete a screening. Your eyes will remain dilated for 6-8 hours after the procedure, therefore it is recommended that you don't schedule anything important for the rest of the day.
After reporting to our clinic, our staff will escort you to the laser diagnostic room where the process will begin.
Ocular History and Examination
Your personal information will be logged into the hospital records.
Clinical history taking will be performed. Your ophthalmic history, medical history, and family history will be reviewed. Please take note of all the medications that you rare currently taking.
Please hand over all of your current prescription eye glasses so that our optometrist may record the power.
VISION AND REFRACTION
Your visual acuity will be taken with and without your current prescription eye glasses. Automated refraction, manual/manifest refraction and dilated/cycloplegic refraction will be done. All these measurements are critical in determining your best potential visual acuity.
SLIT LAMP BIOMICROSCOPY.
Your eyelids, eyelashes, and the anterior segment (conjunctiva, cornea, pupil, iris, and lens) of your eye will be examined with a slit beam of light. This examination is performed to search for lid and lash conditions, corneal diseases, pupil and iris abnormalities, and cataract grading.
OCULAR SURFACE EVALUATION
Fluorescein dye applied on your eye will be used to examine the ocular surface for signs of dry eye disease. Your tear break up time (TBUT) will be measured. In some instances, the use of a Rose Bengal or Lissamine Green dye strip may be necessary.
APPLANATION TONOMETRY (Haag Streit Goldmann)
A topical anesthetic, proparacaine, will be instilled into your lower eye lid pocket in order to numb your eye. A fluorescein dye will be used together with a cobalt blue filter to measure your ocular pressure. Your eye pressure will be correlated with your corneal thickness. This examination is used to screen for glaucoma.
Ocular Diagnostic Tests
PUPILLOMETRY (Oasis Medical Colvard)
An infrared pupillometer will be used in a dark room to check for your pupil size at night. This will assist us in selecting an appropriate optical zone for best night vision. This examination is performed prior to pupil dilation.
OPTICAL BIOMETRY (Zeiss IOL Master)
This is taken to determine the corneal curvature, eyeball length, anterior chamber depth, len thickness, and white-to-white measurements. These numbers are used to compute for your intraocular lens power. This examination is performed prior to pupil dilation.
SPECULAR MICROSCOPY (Topcon)
This measures endothelial cell density (ECD). Low ECD is a risk factor for refractive cataract surgeries that can be missed without the use of a specular microscope. This examination is performed prior to pupil dilation.
CORNEAL TOPOGRAPHY (Zeiss Atlas Pathfnder)
The corneal curvature is measured using this diagnostic test. It will show the flat and steep areas of your cornea. This helps in screening for keratoconus, which affects the computation of intraocular lenses for cataract surgery. This examination is performed prior to pupil dilation.
SCHEIMPFLUG ANALYZER (Oculus Pentacam)
This is an improved version of a corneal topographer. It has the benefit of giving refractive surgeons more information on the curvature and thickness of the cornea. It is very useful in identifying even early keratoconus. This examination is performed prior to pupil dilation.
ABERROMETER (Zeiss WASCA)
Think of this as a super automated refraction machine. Traditionally our refractive errors are determined using an auto refractor, phoropter, or trial lenses. These are able to determine the amount of myopia, hyperopia and astigmatism. However, our eyes as an optical system have higher wavefront measurements that are of consequence to the quality of our vision. The wavefront aberrometer measures the way a wavefront of light passes through the cornea and the crystalline lens, which are refractive components of the eye. Distortions that occur as light travels through the eye are called aberrations, representing specific vision errors. This examination is performed before and after pupil dilation.
OCT MACULA (Zeiss Cirrus OCT )
A special photo of the macula is taken with this machine. The macula is responsible for the central 30 degrees of functional vision. So a fully functioning macula will allow us to see the face of an individual who we are looking at. If this is diseased, we will see a central obstruction in vision. This examination is performed before or after pupil dilation.
OCT OPTIC NERVE (Zeiss Cirrus OCT)
A special photo of the optic nerve is taken with this machine. The optic nerve may be damaged because of glaucoma. Early detection is possible with this diagnostic test. This examination is performed before or after pupil dilation
DILATED FUNDUS EXAMINATION
Dilating ophthalmic drops will be instilled into your lower eye lid to make your pupils dilate. It usually takes around 30 minutes to achieve full pharmacologic pupillary dilation. Dilation will allow us to examine your retina for congenital/acquired posterior segment diseases. We can see retinal tears/holes, macular degeneration, optic nerve diseases, among other things. The presence of any posterior segment condition may disqualify one from having refractive cataract surgery. This is performed by Dr. Roque at the end of the screening process.
Dr. Roque will evaluate the results of your screening and determine if your eyes are fit to undergo refractive cataract surgery. It is at this time that you will be able to ask all your questions about the possible surgical options. If you are accompanied by a decision maker prior to surgery, you may have this person join you for this session.