The inability to see distant objects clearly is one reason that working adults with myopia (near-sightedness) take time from away from work to visit an optometrist. Another reason is an increased need to squint in sunlight and/or increased intolerance to glare. However, near-sightedness may actually be a symptom of keratoconus – a corneal disorder linked to severe vision loss. Specific diagnostic tools are used by optometrists to tell whether a person has keratoconus, and the following is a description of four of these tools.
If you have been told that you have keratoconus, scheduling an appointment at one of the numerous offices of the Precision Keratoconus Center may be a sensible “next step” to understand the treatment options.
Your Family History, Genetics, and Diagnostic Tools
A positive family history (such as a parent with keratoconus) increases the likelihood of developing keratoconus, according to a research article in 2016 in Eye and Vision. This is one reason that eye doctors typically want to know a patient’s family history (as well as medical history) before performing a routine eye exam.
Noted in the Eye and Vision article is that gene sequencing has enabled more genetic-focused keratoconus studies. Moreover, recent findings of various genome-wide linkage studies have suggested involvement of the LOX gene in keratoconus.
While keratoconus often begins in one eye during childhood or adolescence (with subsequently decreased vision in that eye), it most often becomes a bilateral eye disorder over time. Therefore, receiving a keratoconus diagnosis as early as possible is vital to preserving eyesight.
Diagnostic Tool Number 1 – Eye Refraction Test
An eye refraction test (standard vision test) enables the eye doctor to ascertain whether a person has “20-20” vision (which is considered optimal vision). People with vision worse than “20-20” are unable to read letters that are three-eighths of an inch in height from a distance of 20 feet, and their eyesight problem may be due to a refractive error in the eye. The results of this test are utilized to diagnose the following eyesight problems resulting from a refractive error:
- Myopia – commonly referred to as near-sightedness;
- Astigmatism – resulting in blurry vision;
- Hyperopia – commonly referred to as far-sightedness;
- Presbyopia – lessening of the ability to focus the eyes, and typically age-related (i.e., lessening of ability to read small print normally coinciding with aging)
Diagnostic Tool Number 2 – Slit-Lamp Exam
Through using a vertical beam of light directed toward the surface of the eye (and a microscope to evaluate the shape of the cornea), an eye doctor can identify some problems in the eye. A longer than normal eyeball is the usual underlying cause of the progressive corneal thinning (and/or bulging) featured in keratoconus. At an early stage, keratoconus is most often treated with glasses to correct the resulting myopia or contact lenses (per the National Organization for Rare Disorders [NORD]).
Diagnostic Tool Number 3 – Keratometry
A keratometer is a diagnostic tool used to measure the curvature of the anterior surface of the cornea, and can enable an assessment of the level of astigmatism in the eyes. Since an astigmatism affects many people afflicted with keratoconus, a keratometric assessment of the level of astigmatism can particularly help in in developing a treatment plan for a patient who has early keratoconus (such as whether soft contact lenses to correct myopia can be used or not).
Diagnostic Tool Number 4 – Computerized Corneal Mapping
Computerized corneal mapping (or topography) is an imaging technique utilized to characterize the shape of the cornea, and this is necessary prior to most corneal surgeries. The thickness of the cornea can also be determined by computerized corneal mapping. Therefore, this diagnostic tool is useful in classifying whether the keratoconus is mild, moderate, or severe, In turn, this classification can aid in determining the best course of treatment.
By scheduling a consultation at the Precision Keratoconus Center, you can gain a better understanding of your keratoconus treatment options.