Encyclopedia of Health and Medicine

vitrectomy 123
the child’s age, comprehension, and communication
abilities.
Sudden loss of vision in one eye or both
eyes is an emergency that requires
immediate medical care.
Adults are generally able to perceive symptoms
of vision impairment, though when onset is gradual
the symptoms are less obvious (though may be
more apparent to co-workers, friends, and family
members). Sometimes the first indication of a serious
vision impairment comes with a misfortune
such as a motor vehicle accident, especially among
older adults who do not notice or do not acknowledge
diminishing vision. Symptoms of vision
impairment include
• dimness or changes in color perception
• need to hold objects closer or farther away
from eyes
• frequent headaches or squinting
• loss of sharpness or clarity of vision
• difficulty reading
• difficulty seeing at night or in low light
• the need for bright lighting
The diagnostic path includes a comprehensive
ophthalmic examination to assess visual acuity,
visual field, and refractive error as symptoms indicate.
Further diagnostic procedures may be necessary
when the underlying cause of vision
impairment appears to be a health condition other
than a problem with the eyes, such as MULTIPLE
SCLEROSIS or DIABETES.
COMMON CAUSES OF VISION IMPAIRMENT
AGE-RELATED MACULAR
DEGENERATION (ARMD)
AMBLYOPIA
central serous RETINOPATHY
congenital disorders
GENETIC DISORDERS
INFECTION
RETINAL DETACHMENT
retinopathy of DIABETES
retinopathy of prematurity
TRAUMA TO THE EYE
ALBINISM
CATARACT
congenital
CYTOMEGALOVIRUS (CMV)
corneal deterioration
GLAUCOMA
MULTIPLE SCLEROSIS
RETINOBLASTOMA
retinopathy of HYPERTENSION
STROKE
uncorrectable MYOPIA
Treatment Options and Outlook
Treatment depends on the cause of the VISION
IMPAIRMENT. CORRECTIVE LENSES or REFRACTIVE SUR-
GERY typically improve vision in conditions such as
severe MYOPIA or ASTIGMATISM, even if these measures
cannot fully restore normal vision. Surgery is
often the solution for vision impairment due to
CATARACT, CORNEAL INJURY or deterioration, RETINAL
DETACHMENT, and some forms of GLAUCOMA. Medications
can control other forms of glaucoma.
Vision impairment has a significant effect on
QUALITY OF LIFE. There are numerous assistive
devices for people who have functional limitations
as a result of vision impairment. Most people who
have vision impairments are able to participate,
with reasonable accommodations and sometimes
creative effort, in work and recreational activities
they enjoy. Continued advances in technology
generate new treatment approaches that may
offer improved vision.
Risk Factors and Preventive Measures
Many health conditions can contribute to or cause
vision impairment. The most significant are diabetes,
HYPERTENSION, and glaucoma. Early diagnosis
and appropriate treatment can limit or prevent
damage to the eyes and to vision. Eye protection,
such as sunglasses and safety eyewear for activities
with risk for impact or debris, is a key preventive
measure. More than 40,000 preventable eye
injuries occur every year. Routine ophthalmic
examinations detect eye problems early, allowing
for the most appropriate and effective interventions
to preserve vision.
See also BRAILLE; COLOR DEFICIENCY; HEADACHE;
MOTOR VEHICLE ADDIDENTS; VISION HEALTH.
vitrectomy An OPERATION to remove the vitreous
humor from within the EYE as treatment for RETI-
NAL DETACHMENT, vitreous HEMORRHAGE (bleeding
into the vitreous humor), RETINOPATHY, and foreign
body penetration. In vitrectomy, the ophthalmologist
makes three tiny incisions in the sclera (white
portion) of the eye for the insertion of a cutting
instrument, a light, and an infusion tube. The cutting
instrument rotates to gently pull the vitreous
humor out of the eye, and the ophthalmologist
replaces it with a saline-based solution at the same
rate to maintain pressure and stability within the