Optometrists provide functional primary eye and vision care and are generally the first health care practitioners to come up with the diagnosis and clinical myopia management to the majority of the population.
The American Optometric Association has prepared, reviewed and approved the following guidelines for the care of the patients with myopia to aid optometrists in achieving the following objectives:
- diagnosis of the types of myopia
- better quality of care provided to myopic patients
- information dissemination and education of the general public regarding myopia
- low visual morbidity secondary to high degrees of myopia
Myopia is a common visual condition in which near objects are seen clearly but far objects are blurry. It is due to the elongated shape of the eyes causing light rays to refract incorrectly, focusing images in front instead of on the retina.
The application of the proper concave lenses or corneal modification procedures in which corneal refractive power is decreased can restore clear distance vision.
Myopia is highly prevalent and can lead to visual morbidity and increased risk of vision-threatening conditions like retinal detachment and glaucoma.
Classification of Myopia by Clinical Entity:
- Simple Myopia
- most common type
- usually genetic
- may be caused by too much near work
- when the eye is neither too long for its optical power or when its optical power is too high for its axial length (less than 6 D)
- astigmatism commonly co-exists
- Nocturnal Myopia
- occurs only in dim illumination
- due to the increase in accommodative response associated with low light levels
- Pseudomyopia
- overstimulation of the eyes’ accommodative mechanism or ciliary spasm causes an increase in ocular refractive power
- inappropriate accommodative response simulates myopia
- Degenerative or Pathological Myopia
- associated with the degenerative changes in the posterior of the eye
- commonly leads to retinal detachment and glaucoma
- Induced or Acquired Myopia
- due to fluctuations in blood sugar levels, exposure to sulfonamides and pharmaceutical agents, nuclear sclerosis of the crystalline lens
- age-related nuclear cataracts
Risk Factors Associated With Myopia
- genetics, family history
- error of refraction at school entry age
- astigmatism
- esophoria at near, low positive relative accommodation
- more convergent midpoint between the near base-in and base-out fusional vergence ranges
- doing much near work regularly
- steep corneal curvature and an axial length to corneal radius ratio greater than 3.00
- conditions that prevent normal ocular image formation
Early Detection and Prevention
Upon vision screening, myopia can be detected by:
-visual acuity testing
-retinoscopy
-ophthalmoscopy
-autorefraction
-photorefraction
