BY; S.MOETI S/N

DEFINATION

• Refractive errors; are optical imperfections that prevent eye from properly focusing light on the retina.

OrA disorder in which light is not bent

correctly on the retina resulting in a blurred image.

CONT.

• N:B emmetropia ; a normal refractive condition resulting in clear focus on retina with no optical defects.

• it is a normal vision.

RISK FACTORS

1. GENETICS; Some errors such as myopia may be present in heritable connective tissues such as knobloch syndrome.

-linked disorders caused by mutations in loci involved in photo receptor function e.g retinitis pigmentosa

CONT.

2. ENVIROMENTAL; I.Visually intensive occupationsII.Reading is predicted in childrenIII.Socio economic status and higher level of education has also been reported as a risk factor.

TYPES OF REFRACTIVE ERRORS

MYOPIA; near sightedness, difficulty in seeing

distant objects.Close objects are clear, distant objects are

blurry.Occurs in peoplewith elongated eye balls,

because of excessive length of the eye, light rays focus in the vitreous body before

CONT.

…..They can reach the retina.HYPEROPIA; FarsightednessDifficulty in seeing close objects clearlyResults when the eyeball is shorter than normal causing light rays to focus at a theoritical point behind the retina.Demands of reading usually bring

CONT.

• …….Symptoms of headache and eye strain.

CONT.

ASTIGMATISM; Rays of light are not bent equally by the

cornea in all direction so the point of focus is not attained.

Results from unequal curvatures in the shape of cornea i.e. distorted vision resulting from an irregularly curved cornea.

SO;

CONT.

PRESBYOPIA; The natural loss of accommodative capacity

with age. Leads to difficulty in reading and even seeing at arms length…

Occurs because of degenerative changes caused by gradual loss of elasticity of lens, which leads to decreased ability to accommodate or focus for near vision

CONT.

• N:B; transient refractive errors occur in diabetes typically when diabetic control is eratic.

• Transient myopia may be due to medications such as suphonamides

PATHOPHYSIOLOGY

• In normal vision, light rays are bent to focus on the retina.

• In refractive errors, vision is impaired because the light rays are not sharply focused on the retina.

CLINICAL MANIFESTATIONS

DIAGNOSTIC MEASURES

• A comprehensive dilated eye examination.• Retinoscopy:Vision of myopes improves

when concave trial lenses correct the focusing power of the eyes.

• Hypropes experience improvement when convex lenses are used.

• Visual acuity:Snellen chart

MEDICAL MANAGEMENT

MYOPIA Concave /minus lens

HYPEROPIA Convex/plus lens

ASTIGMATISM Cylindric lensPRESBYOPIA Plus lens

CONT.

• Refractive errors can be corrected with eyeglasses, contact lenses or surgery.

 • Eyeglasses: They are the simplest and

safety way to correct refractive errors. Appropriate lenses are prescribed to correct refractive error and give one an optimal vision.

CONT.

• Contact Lenses: Work by becoming the first refractive surface for light rays entering the eye causing a more precise refraction or focus. It provides clearer vision, a wider field of vision and greater comfort

CONT.

• Refractive Surgery: Aims to change shape of the cornea permanently. This change in the eye shape restores the focusing power of the eye by allowing the light rays to focus precisely on the retina for improved vision.

CONT.

• Incisional radial keratotomy( RK):Under local anesthesia,the cornea is reshaped by making incisions.

• Laser assisted situ Keratectomy (LASIK):A corneal flap is created to expose the inner cornea.

• Photo refractive Keratectomy(PRK):Removal of the epithelial layer(top surface)of the cornea exposing the inner cornea curvature of the eye.

NURSING DIAGNOSIS

• Difficulty in reading due to hyperopia as manifested by headache/eye strain

• At risk of injuries due to blurred vision• Difficulty in learning due to hazziness as

manifested by low grades in class.• Impaired comfort due to pain(headache)

AS manifested by groaning/closing of eyes• Low self esteem due to impaired vision as

CONT.

• …..manifested by social withdrawalMANAGEMENT.

• Health educate the patient about his/her condition so that the patient could cope well with the situation and on proper eye care

• Comfort and Reassurance• Family therapy so that they will assist the

patient. 

CONT.

• Assist the patient to choose the right treatment for him/herself.

• Provide or improve patients safety(side rails, non slippery flow and not wet, no hanging or electrical cords on the floor)

• Pain destructive measures(meditation, soft music) and pain killers.

COMPLICATIONS

• Dry eye syndrome• Epithelial abrasion• Infection

THANK THANK YOU!!!!!YOU!!!!!