Refractive errors
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This document discusses various types of refractive errors including myopia, hyperopia, presbyopia, and astigmatism. It describes the causes, clinical features, diagnostic evaluations including history, slit lamp exam, and tonometry, and management including pharmacological treatments, and surgical procedures like LASIK and LASEK. Nursing management focuses on safely administering treatments, monitoring vitals, and observing patients for side effects and responses to treatment.
Refractive errors
- 1. REFRACTIVE ERRORS SUDESHNA BANERJEE DUTTA SENIOR LECTURER S.R.S.V.M B.SC NURSING COLLEGE
- 2. INTRODUCTION ✓Refractive errors means that the shape of eye doesn’t bend light correctly resulting in a blurred image . ✓The main types of refractive errors are 1. Myopia ( near sightedness ) 2. Hyperopia (hypermetropia ) ( far sightedness ) ( long sightedness ) 3. Presbyopia ( loss of near vision with age ) 4. Astigmatisms ( both) ( near sightedness ) ( long sightedness )
- 3. ❑ Emetropia (optically normal eye) can be defined as a state of refraction, when the parallel rays of light coming from infinity are focused at the sensitive layer of retina with the accommodation being at rest ❑ Ametropia (a condition of refractive error) is defined as a state of refraction, when the parallel rays of light coming from infinity, (with accommodation at rest), are focused either in front or behind the sensitive layer of retina
- 4. ERRORS ✓Myopia or short-sightedness is a type of refractive error in which parallel rays of light coming from infinity are focused in front of the retina when accommodation is at rest
- 5. ETIOLOGY Axial myopia results from increase in the antero- posterior length of the eyeball Curvatural myopia occurs due to increased curvature of the cornea, lens or both. Index myopia results from increase in the refractive index of the crystalline lens associated with nuclear sclerosis.
- 6. ETIOLOGY Infection adenovirus Injury due to optic nerve damage Ultraviolet radiation eye disease Inherited Aging ( above 45year ) Environmental factors Previous corneal injury Previous eye surgery Optic nerve hypoplasia
- 7. TYPES OF MYOPIA Congenital Myopia is present since birth. Usually the error is of about -8 to -10 diopters, which mostly remains constant. It may be associated with other ocular congenital anomalies Simple Myopia It is the commonest variety, which results from biological variation in the development of eye. simple myopia starts at school age and very slowly progresses till adult age. Usually the error does not exceed -6 to -8 diopters Pathological Myopia or Degenerative Myopia is a rapidly progressive error resulting in high myopia. (more than -8 D) during early adult life, which is usually associated with degenerative changes in the retina Genetic factors play major role in the etiology of pathological myopia.
- 8. HYPEROPIA Far-sightedness also known as long sightedness Hyperopia is a condition of the eye in which light is focused behind the retina , instead of on the retina. Resulting in an inability to seen near objects clear . Causes: Abnormal shape of cornea
- 10. HYPEROPIA Axial hypermetropia is by far the commonest form. It occurs due to short axial length of the eyeball Curvatural hypermetropia occurs due to comparatively flatter curvature of the cornea or lens or both Index hypermetropia results due to change in the refractive index of the lens Positional hypermetropia results due to posteriorly placement of crystalline lens
- 11. HYPEROPIA Absence of the lens (aphakia) either congenital or acquired (following surgical removal of the lens) leads to high hypermetropia.
- 12. CLINICAL FEATURES Tiredness of Eyes Frontal Or Fronto-temporal Headache Watering Mild Photophobia Asthenopia (Straining of eyes)
- 13. MANAGEMENT Appropriate convex lenses in the form of spectacles or contact lenses SURGICAL MANAGEMENT Refractive corneal surgery
- 14. PRESBYOPIA Presbyopia is a common type of vision disorder that occurs as you age. It is often referred to as the aging eye condition . Result in the inability to focus up close , a problem associated with refraction in the eye
- 16. ETIOLOGY OF PRESBYOPIA Decrease in the accommodative power of crystalline lens with increasing age, leading to presbyopia occur due to: Decrease in the elasticity and plasticity of the crystalline lens Age related decrease in the power of ciliary muscle.
- 17. CLINICAL FEATURES Typically patient complains of slowly progressive difficulty in focusing the near objects, while distant vision is not affected.
- 18. MANAGEMENT Convex glasses of an appropriate power
- 19. ASTIGMATIS M It is a condition in which an abnormal curvature of the cornea occurs . Astigmatisms may cause eye strain and may be combined with nearsightedness or long- sightedness .
- 21. ASTIGMATISM Usually occurs due to unequal curvature of cornea Rarely it may occur due to subluxation abnormalities of the curvature of the lens.
- 22. MANAGEMENT Cylindrical lenses in the form of spectacles or contact lenses SURGICAL MANAGEMENT Keratoplasty
- 23. Y Due to etiology factors such as infection Degenerative changes causes by gradual loss of elasticity of lens Decreased ability to accommodate Refractive errors
- 24. DIAGNOSTIC EVALUATION HISTORY TAKING CORNEAL TOPOGRAPHY: This computerized test maps the curve of your eye cornea , it can show problem with eye surface like swelling or scarring SLIT LAMP EXAM: The doctor uses this microscope to shine a beam of light shaped like a small slit on effected eye .he may dilated pupils during the test it help diagnose .
- 26. SLIT LAMP EXAM
- 27. DIAGNOSTIC EVALUATION TONOMETRY: Test measures the pressure inside eye .which is called intra ocular pressure RETINOSCOPY: Is a technique obtain an objective measurement of the refractive error of a patients eye
- 29. PHARMACOLOGICAL MANAGEMENT Cycloplegic drugs are used to refraction ( to paralyze the ciliary muscle in order to determine the true refractive error of eye ) Cholinergics (Miotics): Pilocarpine, Carbachol - It increases aqueous fluid outflow by contracting the ciliary muscles Beta blockers : Betaxolol, Timolol Decreases aqueous humor production
- 30. SURGICAL MANAGEMENT Keratomileusis: Is a method of reshaping the cornea surface to change its optical power. LASIK- laser eye surgery : ( laser assisted in situ kereto- mileusis ) ✓This procedure used to treat nearsightedness ,farsightedness ✓A laser is used to reshape the cornea – the clear ,round dome at the front of the eye ✓To improve the way the eye focuses light rays onto the retina at the back of the eye.
- 31. SURGICAL MANAGEMENT AUTOMATIC LAME -LLAR KERATOPLASTY (ALK) ✓Keratoplasty is the procedure where by abnormal corneal tissue is replaced by a healthy donor cornea ✓Is a older type of vision surgery carried out by making a flap in the cornea to help correct severe short sightedness and long sightedness.
- 32. SURGICAL MANAGEMENT LASEK LASSER ASSISTED SUB EPITHELIAL KERATOMILEUSIS : The hinged flap made in laser assisted epithelial kerato-mileusis surgery is created in the epithelial layer of eye . Inserted of creating a thicker corneal flap as in laser assisted epithelial kereto- mileusis surgery PHOTO REFRACTIVE KERETOTOMY (PRK) : To correct myopia The eye surgeon then gently remove the surface of corneal cells ( epithelium )
- 33. NURSING MANAGEMENT Safe administration of the prescribed fluid Right documentation Monitor the hemodynamic pressure, vital sign, arterial blood gas Assess the patient for any previous allergy to medicine, fruits etc When we administer any new medicine we have to observe the side effect of it We must have the knowledge about the sign symptoms of shock Observe the response to the treatment