Encyclopedia of Health and Medicine

H
hordeolum A bacterial INFECTION of a gland or an
eyelash follicle along the edge of the eyelid, commonly
known as a stye. A hordeolum causes
swelling, redness, PAIN, and a discharge that leaves a
crusty layer on the eyelids during sleep. The doctor
can usually diagnose hordeolum by its presentation.
BLEPHARITIS (infection of the inside surface of
the eyelid) and CONJUNCTIVITIS (infection of the conjunctiva,
the membrane lining the eyelids) may
instigate, accompany, or follow hordeolum. The
doctor often chooses to anesthetize the area and
lance (make tiny punctures or incisions under sterile
conditions) the hordeolum to drain its contents
and relieve the pressure. Further treatment is ophthalmic
ANTIBIOTIC MEDICATIONS, typically in ointment
form, applied to the area. Sometimes oral
antibiotic medications are also necessary. Warm,
moist compresses soothe the irritated tissues and
help draw out any remaining pus.
Most hordeola clear up in 7 to 10 days with
treatment and heal without residual consequences.
A hordeolum does not itself cause VISION
IMPAIRMENT, though untreated hordeola can lead to
significant EYE problems if the infection spreads to
other structures of the eye. Some people experience
recurring hordeola, while others experience
only a single episode. A hordeolum may also form
the basis for a CHALAZION (painless nodule) to
develop in its place.
See also BACTERIA; ECTROPION; ENTROPION.
hyperopia A refractive error, commonly called
farsightedness, in which the EYE has difficulty
focusing on near objects. Hyperopia results when
the focal point of lightwaves entering the eye
extends past the RETINA, causing the images the
retina registers to be blurred. The refractive error
occurs because the distance from the front to the
back of the eye is shorter than normal. Symptoms
of hyperopia include
• squinting when reading or doing close work
• HEADACHE
• fatigued eye muscles (aching around the eyes)
• blurred vision when looking at near objects yet
clear vision when looking at distant objects
CORRECTIVE LENSES (eyeglasses or contact lenses)
can compensate for hyperopia by altering the focal
point of lightwaves so it falls directly on the retina.
They do so by refracting (bending) the lightwaves
outward. REFRACTIVE SURGERY, which permanently
alters the shape of the CORNEA, can provide refractive
correction for people with mild to moderate
hyperopia. Hyperopia sometimes occurs following
refractive surgery for MYOPIA (nearsightedness) as
a consequence of overcorrection. Eye professionals
denote refractive corrections in units of measure
called diopters. For hyperopia, the expression
of diopter is a positive number. Corrective lenses
for hyperopia have a magnifying appearance that
make the eyes look bigger than they are.
Hyperopia is less common than myopia, affecting
about 20 to 25 percent of adults. Few people
who have hyperopia have greater than +6
diopters of refractive error, so nearly always corrective
measures result in normal VISUAL ACUITY.
See also ASTIGMATISM; PRESBYOPIA; REFRACTIVE
ERRORS.
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