A comprehensive eye exam is a thorough assessment of vision and ocular health. Dr. Louis Bahoshy and the optometrists at Stoney Creek Eye Care may use a wide variety of tests and procedures as needed during your comprehensive examination:
Your optometrist will ask you a series of questions to get a better idea on your vision and medical history and to get a better understanding of your overall visual needs. This will include any specific concerns you have or changes with respect to your vision, your family’s visual and medical history, your visual needs at school, occupation, hobbies, etc.
Visual acuity is the measurement of the sharpness or clarity of vision. This is measured by your ability to identify letters or numbers on a standardized eye chart from a specific distance. The smaller the letters you can read from that distance, the better your visual acuity is. For example, a visual acuity of 20/20 means that the person can see letters that are half the size that someone with 20/40 vision can see. Your optometrist may check your uncorrected visual acuity (without glasses or contact lenses) or corrected visual acuity (with glasses or contact lenses). “Distance Visual Acuity” measures the ability to see detail across the room and much further away whereas “Near Visual Acuity” measure the ability to see detail usually at a reading distance. Our near visual acuity usually tends to decline with age and usually most patients that have had great vision throughout life usually will require corrective glasses to read usually in their forties. This is called “presbyopia” and it is due to the natural lens in the eye becoming less flexible with age.
Binocular Vision (BV) Testing
Binocular vision is the ability of both eyes to work in harmony with each other. A simple test such as a “cover test” can pick up strabismus (abnormal alignment of the eyes that is always present) or a phoria (the tendency of the eyes to want to turn but are usually aligned under normal viewing). More detailed testing can be performed later in the examination if the screening here shows any abnormalities.
Colour Vision testing
Your optometrist will check for hereditary colour vision deficiencies with a simple screening test such as the “Ishihara test” or “D-15 test”. These are much more common in males due to the way they are passed on genetically. Colour vision deficiency usually affects approximately 1 in 12 males (12%) and 1 in 200 females (0.5%). The vast majority of colour deficient patients will still see colours but have a tendency to confuse certain colours with each other. Red-Green colour defiance is common.
Ocular Motility Testing
Ocular motility (eye movement) testing determines how well your eyes can follow a moving target (smooth pursuits) or can accurately move from one target to the next (saccades). Problems with ocular motility can result in eye strain, difficulty in accurate reading and difficulty in certain sports.
Stereopsis is the ability to have accurate depth perception. The “Randot Test” involves wearing 3D glasses and looking at images in a booklet to determine which test pattern appears closer to you than the others. Patients with good binocular vision (see above) usually also have good stereopsis. Patients with strabismus usually have a more difficult time with accurate depth perception.
This is the part of the eye exam where your optometrist determines your refractive error accurately. This determines whether you will need glasses and also the exact parameters of your spectacle prescription. Refraction can be objective or subjective.
Subjective refraction is when your optometrist will use a phoropter to determine your prescription. This involves rotating different lenses in a systematic way and with the help from the patient, an accurate prescription is determined.
Objective refraction is the technique of determining the prescription with little or no help from the patient. Retinoscopy involves using a handheld device with a built in light and lenses to analyze the reflex coming back from the patient’s pupil. The optometrist then rotates the lenses in a systematic manner to determine the prescription. This is very useful in younger children who cannot properly cooperate for a subjective refraction.
The auto-refractor is an instrument that is used to get an objective refraction. This involves looking at a target and the instrument sends beams of light which bounce back from the patient’s cornea and an estimation of the refraction is determined. Your optometrist will use this only in conjunction with other subjective techniques to determine your accurate refraction.
Your final prescription is determined by your optometrist by factoring in various parameters including the discussion of your specific visual needs at your workplace, lifestyle needs, etc. Specific recommendations and advise will be provided.
Slit Lamp Examination
A slit lamp (or biomicroscope) is used by your optometrist to examine the structures of the eye under high magnification. A wide number of conditions can be detected by the slit lamp exam. These include corneal conditions, conjunctivitis, cataracts, macular degeneration, diabetic retinopathy and many other conditions.
This is the measurement of the pressure in the eyes. High intra-ocular pressures are a risk factor for developing a condition called glaucoma. At Stoney Creek Eye Care we have invested in the icare ic100 tonometer which requires no drops and no air puff is involved!
Drops may be used to dilate the pupils to in order to get a clearer view of the eye’s internal structures to look for retinal conditions such as vitreous floaters, retinal tears, retinal degenerations, etc.
Digital Retinal Imaging
At the end of the eye examination, your optometrist will summarize the results of the exam and based on earlier discussions during the exam, recommendations will be made if a visual correction is needed. In the case of ocular health issues, the condition will be described and treatment initiated with follow-ups scheduled as needed. Timely referrals to an ophthalmologist will be provided if needed.