Hypermetropia

Dr.Siddharth Gautam& Dr.Pavitra Patel
Resident Ophthalmology
JNMC,Wardha

1. HYPERMETROPIA Dr. Siddharth Gautam

2. The term hypermetropia is derived from HYPER meaning “In excess” MET meaning “measure” & OPIA meaning “of the eye”. Also called hyperopia / longsightedness as the distant objects are seen clearly but the close objects do not come into proper focus. First suggested in 1755 by KASTNER ( Mathematician)

3. DEFINITION It is the refractive state of eye where in parallel rays of light coming from infinity are focused behind the sensitive layer of retina with accommodation being at rest. The posterior focal point is behind the retina which receives a blurred image

4. ETIOLOGY 1) AXIAL Most common Axial length is short 1mm shorting of AP dia  3 D of HM At birth +2.5 – 3 D of HM (physiologically) Phyiologically more than 6D HM are uncommon

5. 2) CURVATURAL Flattening of cornea, lens or both 1mm increase in Radius of curvature  6D of HM Never exceed 6D HM physiologically Congenitally flattened is c/a cornea plana Result (trauma and disease ) 3) INDEX Change in refractive index with age Physiologically in old age Pathologically in diabetics under treatment

6. 4)POSITIONAL Posteriorly placed crystalline lens Occurs as congenital anomaly Result of trauma or disease 5)ABSENCE OF LENS Seen in aphakia

7. PHYSIOLOGICAL HYPERMETROPIA Many children are born with hyperopia , and some of them "outgrow" it as the eyeball lengthens with normal growth. The prevalence of hyperopia -unlike that of myopia changes very slowly with the years, and because once hyperopia is present, it progresses slowly or not at all. So, the conventional wisdom is that hyperopia occurs as a result of genetic influences.

8. CLINICAL BACKGROUND Most newborn infants have mild hyperopia , with only a small number of cases falling within the moderate to high range. Infants with moderate to high hyperopia ( +3.50D) are up to 13 times more likely to develop strabismus by 4 years of age, and they are 6 times more likely to have reduced visual acuity than infants with low hyperopia or emmetropia .

9. CLINICAL TYPES SIMPLE HYPERMETROPIA, PATHOLOGICAL FUNCTIONAL HYPEROPIA

10. SIMPLE HYPERMETROPIA Commonest form Results from normal biological variations in the development of eyeball Include axial and curvatural HM May be hereditary

11. PATHOLOGICAL HYPERMETROPIA Pathologic hyperopia may be due to maldevelopment of the eye during the prenatal or early postnatal period, a variety of corneal or lenticular changes, chorioretinal or orbital inflammation or neoplasms , or to neurologic- or pharmacologic-based etiologies. • It is rare in comparison with physiologic hyperopia . • Because of the relationship of pathologic hyperopia to potentially serious ocular and systemic disorders, proper diagnosis and treatment of the underlying cause may prove critical to the patient's overall health.

12. Microphthalmia (with or without congenital or early acquired cataracts and persistent hyperplastic primary vitreous) and this condition's often hereditary form, nanophthalmia , may produce hyperopia in excess of +20D. • Anterior segment malformations such as corneal plana , sclerocornea , anterior chamber cleavage syndrome, and limbal dermoids are associated with high hyperopia . • Acquired disorders that can cause a hyperopic shift result from corneal distortion or trauma, chalazion , chemical or thermal burn, retinal vascular problems, diabetes mellitus, developing or transient cataract or contact lens wear.

13. Conditions that cause the photoreceptor layer of the retina to project anteriorly (idiopathic central serous choroidopathy and choroidal hemangioma from Sturge -Weber disease) also induce hyperopia . Orbital tumors, idiopathic choroidal folds, and edema can mechanically distort the globe and press the retina anteriorly , thereby causing hyperopia . Cycloplegic agents may induce hyperopia by affecting accommodation, and a variety of other drugs can produce transient hyperopia .

14. FUNCTIONAL HYPERMETROPIA Results from paralysis of accommodation Seen in patients with 3 rd nerve paralysis & internal ophthalmoplegia

15. CATEGORISED BY DEGREE OF REFRACTIVE ERROR • Low hyperopia consists of an error of +2.00 diopters (D) or less. • Moderate hyperopia includes a range of error from +2.25 to +5.00 D. • High hyperopia consists of an error over +5.00 D.

16. NOMENCLATURE TOTAL HYPERMETROPIA= LATENT + MANIFEST (facultative + absolute)

17. TOTAL HYPERMETROPIA It is the total amount of refractive error,estimated after complete cycloplegia with atropine Divided into latent & manifest

18. LATENT HYPERMETROPIA (Hl) Amount of hyeropia corrected by inherent tone of ciliary muscle (Usually about 1D) Degree of Hl High in children Decreases with age Revealed after abolishing tone of ciliary muscle with atropine

19. MANIFEST HYPERMETROPIA Remaining part of total hypermetropia Correct by accommodation and convex lens Consists of facultative & absolute FACULTATIVE HYPERMETROPIA Corrected by patients accommodative effort ABSOLUTE HYPERMETROPIA Residual part not corrected by patients accommodative effort

20. Manifest HM – absolute HM = Facultative HM (Strongest lens) – (weakest lens) Total HM – Manifest HM = Latent HM

21. NORMAL AGE VARIATION At birth +2+3D HM Slightly increase in one year of life, Gradually diminished until by the age 5-10 years In old age after 50 year again tendency to HM Tone of ciliary muscle decreases Accommodative power decreases Some amount of latent HM become manifest More amount of facultative HM become absolute Practically after 65 year all of it become absolute

22. SYMPTOMS Principal symptom is blurring of vision for close work Symptoms vary depending upon age of patient & degree of refractive error 1.ASYMPTOMATIC small error produces no symptoms Corrected by accommodation of patient

23. 2.ASTHENOPIA Refractive error are fully corrected by accommodative effort Thus vision is normal Sustained accommodation produces symptoms Asthenopia increases as day progresses Increased after prolonged near work SYMPTOMS Tiredness Frontal or fronto temporal headache Watering Mild photophobia

24. To keep the image focused on retina an excessive amount of accomodation is required in uncorrected hyperopia , the visual system has three choices: 1. The visual system can let the letters go out of focus, making reading impossible. 2. One eye may turn inward, toward the nose, relieving the eyestrain but causing double vision. 3. Single vision may be maintained, but at the cost of large amount of stress due to the continual unconscious effort to keep the eye from overconverging , and thus avoid double vision.

25. 3.DEFECTIVE VISION WITH ASTHENOPIA Not fully corrected by accommodation Defective vision for near more than distance Asthenopia due to sustained accommodation Refractive error more(>4D) 4.DEFECTIVE VISION ONLY Refractive vision more than 4D Adults who usually do not accommodate Marked defective vision for near and distance

26. 5. The effect of aging on vision : Progressive loss of accomodative power with ageing  progressive loss of vision. 6. Intermittent sudden blurring of vision: May occur due to spasm of accomodation inducing pseudomyopia Cycloplagic refraction reveals the underlying hyperopia

27. SIGNS VISUAL ACUITY : Defective EYEBALL: small or normal in size CORNEA : may be smaller than normal. There can be CORNEA PLANA ANTERIOR CHAMBER : may be shallow LENS: could be dislocated backwards A Scan ultrasonography (biometry) reveal short axial length

28. FUNDUS: DISC: Dark reddish color, irregular margins ,confused with Papillitis so termed as PSEUDO-PAPILLITIS MACULA: Situated farther from the disc than usual, large positive angle alpha, apparent divergent squint BLOOD VESSELS: Show undue tortuosity & abnormal branchings BACKGROUND: SHOT- SILK RETINA ( shiney )

29. COMPLICATION Recurrent styes blepharitis or chalazia Accommodative convergent squint Amblyopia Anisometropic Strabismic Uncorrective bilateral high hypermetropia Predisposition to develop primary narrow angle glaucomas . (small eye ball , shallow AC)

30. BASIS FOR TREATMENT No Treatment Error is small Asymptomatic Visual acuity normal No muscular imbalance TREATMENT

31. Young children(<6 or 7yrs) Some degree of hypermetropia is physiological so no correction Treatment is required if error is high or strabismus is present working in school small error may require correction In children error tends normally to diminish with growth so refraction should be carried out every six month and if necessary the correction should be reduced , ortherwise a lens which is overcorrecting their error may induce an artificial myopia. No deduction of tonus allowance in strabismus

32. ADULTS If symptoms of eye-strain are marked , correct as much of the total hypermetropia as possible , trying as far as we can to relieve the accommodation When there is spasm of accommodation we correct the whole of the error Some patients with hypermetropia do not initially tolerate the full correction indicated by manifest refraction so we undercorrect them Exophoria hyperopia should be under correct by 1 to 2D

33. Patients with absolute hypermetropia are more likely to accept nearly the full correction because they typically experience immediate improvement in visual acuity In pathological hypermetropia the underlying cause rather than the hypermetropia is chief concern

34. MODE OF TREATMENT SPECTACLES CONTACT LENS SURGICAL OPTICAL TREATMENT

35. SPECTACLES Basic principle Prescribe convex lenses (Plus lenses) so that rays are brought to focus on the retina Advantages Comfortable Easier method Less expensive Safe

36. CONTACT LENS ADVANTAGES: Cosmetically good Increased field of view Less magnification Elimination of aberrations & prismatic effect

37. REFRACTIVE SURGERY Refractive surgery is not as effective as in myopia TYPES: (1)HEXAGONAL KERATOTOMY(HK) Low to moderate degrees of hypermetropia Its risk /benefit ratio is not low enough to warrant its continued use

38. LASER THERMAL KERATOPLASTY(LTK) Procedure done using Thallium-Holmium-Chromium (THC:YAG) laser energy to heat the cornea (contraction of collagen) and increase its curvature Central heating of cornea results in central corneal flattening thereby resulting in hyperopic shift

39. PHOTOREFRACTIVE KERATECTOMY(PRK) Direct laser ablation of corneal stroma after removal of corneal epithelium mechanically Done using EXCIMER LASER

40. LASER IN SITU KERATOMILEUSIS(LASIK) Anterior flap of cornea lifted with keratome and excimer laser is used to sculpt the stromal bed to change the refractive error of eye It can correct up to 4D of hypermetropia and 8D of astigmatism

41. CONDUCTIVE KERATOPLASTY Discovered by Mendez Uses radiofrequency to gently heat and shrink corneal collagen tissue at specific sites to create bands of tightening. The band reshapes and steepens cornea to correct hyperopia . INDICATIONS: Patients >40yrs having stable refraction Hyperopia from +0.75 to +3.25D with -0.75 or less astigmatism.

42. ADVANTAGES Minimally safe and effective for hyperopia upto +4 D Depth perception is maintained Contrast sensitivity is not lost from preoperative levels DISADVANTAGES Not affective in hyperopia of >+ 4.0 D and 0.75D astigmatism Non reversible Recurrent corneal erosions, perforation, mild iritis are rare but do occur

43. PHAKIC IOL AND CLEAR LENS EXTRACTION Done by Phaco technique Clear lens extraction with the implantation of an IOL-----Preferably foldable IOL or a Piggyback IOL is implanted. (>+10D)

44. VISUAL HYGIENE While reading or doing intensive near work take a break about every 30 min When reading maintain proper distance that is the book should be at least as far from your eyes as your elbow when you make a fist and hold it against your nose Sufficient Illumination Place a limit spent watching television & watching videogames Sit 5-6 feet away from the television

45. Appropriate optical correction almost always leads to clear and comfortable single binocular vision Younger children who have significant hyperopia associated with amblyopia , strabismus,or anisometropia require treatment, starting as early as 3-6 months of age

46. CONCLUSION Hyperopia is a common refractive disorder that has been overshadowed by myopia in public perception,vision research & the scientific literature Although uncorrected myopia has a greater adverse effect on visual acuity than uncorrected hyperopia,the close association between hyperopia,amblyopia & strabismus,especially in children,makes hyperopia a greater risk factor for more permanent vision loss than myopia

47. The early diagnosis & treatment of significant hyperopia & its consequences can prevent a significant amount of visual disability in the general population

48. THANK YOU