- Presbyopia is the age-related loss of accommodation due to reduced elasticity of the lens and ciliary muscles. It starts in the 40s and complete loss of accommodation occurs by 50-60 years.
- Theories of accommodation include the Helmholtz theory of ciliary muscle contraction relaxing the zonules to allow lens curvature change, and the Schachar theory of reduced perilenticular space limiting ciliary muscle effect.
- Risk factors include occupation, geography, gender, medical conditions, and drugs. Treatment options include glasses, contact lenses, and various surgical procedures like LASIK, multifocal IOLs, and scleral expansion bands.
2. PRESBYOPIA
• Physiological progressive age related loss of
accomodation due to reduced amplitude leading
to progressive fall in near vision.
• 1.3 billion world wide.
• Starts early in life.
• Loss of functional vision :in 40’s.
• Complete loss of accomodation in 50-60 years.
4. IN PRESBYOPIA
ciliary muscle contraction ceases
posterior zonular fibres pull the ciliary muscle
backward
increased tension on the zonular fibres
increase in lens diameter, decrease in lens thickness and
a flattening of the anterior and posterior lens surface
curvatures
decrease in optical power
6. IN PRESBYOPIA
growth of equatorial diameter of the lens
with age ,the perilenticular space is reduced
ciliary muscle contraction no longer tense the
zonules and expand coronally
• Based on this theory new sx for presbyopia
scleral expansion bands was introduced.
7. CATENARY THEORY BY COLEMAN
lens zonules and anterior vitreous comprises of a
diaphram b/w AC and vitreous
8. IN PRESBYOPIA
Increased lens volume with age results in a
reduced response of anterior radius of
curvature to the vitreous pressure gradient
created by ciliary body contraction.
13. • N/l young p/t-> lens can autofocus.
• Emmetrope:far point-α
Near point –increases with age.
• 10 yrs – 7 cms
• 20 yrs- 10 cms
• 30 yrs-14 cms
• 40 yrs- 20 cms
• 50 yrs-40 cms
• Amplitude of accomodation:
• 10 yrs-14 D
• 20 Yrs-10D
• 30 Yrs-7D
• 40 yrs-5D
14. • For comfortable vision
• >40 cms:1/2 of accomodation is to be kept in reserve.
• <40 cms:1/3 rd of accomodation is to be kept in
reserve.
• Usually near work becomes difficult when amplitude
of accomodation is <5 D.
AGE & PREDICTED NEAR ADD
• 45 yrs - +1D
• 50 Yrs-+1.50 D
• 55 yrs-+2.00 D
• 60 yrs-+2.25 D
15. CLASSIFICATION
• Incipient presbyopia:
• beginning stage
• Difficulty in near vision during dim illumination bt n/l on bright
illumination
• Premature presbyopia:
• occur at an earlier stage than expected for n/l population.
• Causes:ocular d/s,uncorrected hyperope,c/c simple glaucoma
General debility,presenile ciliary muscle weakness ,
Premature sclerosis of lens.
• Manifest presbyopia:
• presbyopia with some amplitude of accomodation.
• Absolute presbyopia:
• Amplitude of accomodation is completely absent
16. C/F
• Difficulty in near vision initially in evening and dim
light and latter even in good light
• Asthenopic symptoms like headache d/t fatigue of
ciliary muscles
• Intermittent diplopia due to associated disturbances
of convergence.
Aggravated by fatigue/ illness/ fever / other c/c d/ses.
SIGNS
• Reduced amplitude of accomodation
17. TESTS FOR NEAR VISION
• Addition based on amplitude of accommodation.
• Tentative addition based on age.
• Plus build-up method.
• Bichrome method.
• Cross-cylinder method.
• Relative accommodation method.
• Dynamic Retinoscopy method.
18. ADDITION BASED ON AMPLITUDE OF
ACCOMMODATION
• PRESBYOPIA
• NPA exceeds 8 inches (22cm) (Donders).
• amplitude of accommodation < 5D (Morgan).
Working distance (WD) = 40cm
RAF (Amp accommodation) = 2.00D
What should be the near addition ???
• Accommodation required for WD = 2.50 D
Accommodation in Reserve = 1.00D
• Amount of accommodation left = 1.00D
• Amount of Near addition = (2.50 –1.00)
= 1.50D
19. Working distance (WD) = 25 cm
RAF (Amp accommodation) = 1.50D
What should be near addition ???
Accommodation needed at WD = 4.00D
Amplitude held in reserve = 0.50D
Amplitude of accommodation left = 1.00D
Amount of near addition = (4.00-1.00)
= 3.00D
20. TENTATIVE ADDITION BASED ON AGE
Amplitude of accommodation to age (Hofstetter)
◦ Maximum = 25.0 – 0.4 (age)
◦ Probable = 18.5 – 0.3 (age)
◦ Minimum = 15.0 – 0.25 (age)
21.
22. PLUS BUILD UP METHOD
• The least amount of + lens which gives p/t a better
vision at near detected.
• BCVA kept b4 the p/t.
• At 40 cms: 6/6 line / letter : target.
• Ask if p/t sees clearly.
• If blurry add + lenses increased in steps of 0.25D to
the amount necessary to read the desired letters at
a customary working distance.if better:add 1 more
+,if same :back up 1 to get end point.
• Can be done binocularly or monocularly .
• Monocular build-up has amount of near addition
higher than binocular.
23. BICHROME METHOD
• Chromatic aberration
• Patient with distant BCVA
• Bichrome test at habitual distance in NV
• Ask patient which background letters are more
clear , Green-add plus, Red-remove plus until
he/she sees letters equally clear in both.
• In presbyopic patients red & green are focused
behind the retina with red farther away.
• Green appears clear.
• Plus lenses are added until both red & green appear
equally clear
24.
25. CROSSED CYLINDER TECHNIQUE
• A near point grid is diffusely illuminated & placed at
p/t’s customary working distance .Plus lenses are
added until lines seen clearly.
• Crossed cylinder (±0.50D) with their minus axes vertical
are placed before the patient’s eyes & asked to report
which sets of lines running across or up & down appear
clearer, sharper, blacker
• artificial astigmatism with an interval of sturm of 1D
created.
• If accommodates exactly for the target, both sets of
lines should be equally clear.
• under-accommodation, the horizontal lines will b
clear.Add positive lenses until lines are equally clear.◦
Can be done monocularly or binocularly
26.
27. RELATIVE ACCOMODATION METHOD
• Patient is provided with plus lenses determined by
other methods.target @ 40 cms 6/6 line.
• Determine :Plus lens to blur (NRA)
: Minus lens to blur(PRA)
• Near add = NRA+PRA/2
• THE NEAR ADD IS 1.00 (SAY)
• ADD MINUS LENSES UNTIL BLUR (1- 0.5)= +0.50 D
• ADD PLUS LENSES UNTIL BLUR (1+1) = +2.00 D
• FINAL ADD IS (+0.50+2.0)/2= 1.25D
29. MONOVISION
• presbyopia therapy
• Achieved through contact lenses or surgically at the
corneal or lenticular plane.
• Mild myopia –0.5 to –1.5D in non- dominant eye (avoid
anisometropia no more than 2D diff between the eyes)
• Need to be able to suppress blurred image • Only a
mild decrease in distance, good stereo, very good
intermediate vision.
• C/I:
• with high visual requirements for near or distance
• .
30.
31. GLASSES AND CONTACT LENSES
• Converging or plus lenses for near work .
• Change in prescriptions every two to three years.
36. CONDUCTIVE KERATOPLASTY
• Radio frequency energy is applied to mid peripheral
corneal stroma via probe that heats up the collagen and
causes it to shrink .
• Induces up to 1.5 to 2.0D of central steepening & corneal
flattening .
• Non-dominant eye corrected for near(monovision).
• Amt. of steepening α no. of spots & rings.
• Advantages:Extraocular, Relatively inexpensive,Can be
done with slit lamp ,And by non refractive surgeons .
• Disadvantage:Limited to hyperopes or emmetropes
,Induce irregular astigmatism , Regression of effect,
Corneal scaring
37.
38. Corneal Inlays
• Made of Biocompatible material placed in a pocket
created with a microkeratome or intralase flap within
cornea .
• Designed for use in emmetropic or hypermetropic eyes
• Aperture 1.6mm, outer rim 3.8mm .
• Pin hole effect increases depth of focus & alter the
way light rays enter the eye .
• Micro pores for nutrients.
• Advantages: a) Extraocular surgery b) Reversible
c) Exchangeable
• Eg: Kamra small aperture corneal inlay
39. • Flexivue Microlens
• 3-mm in diameter,15 microns thick.
• The lens is placed about 280 to 300 microns deep in
the cornea of non-dominant eye through a pocket
created using a femtosecond laser.
• The specific vision-correcting prescription is
incorporated in the outer area of the lens.
• Advantage :
10 min procedure,
pocket created self-seals & holds the lens in place.
40.
41.
42. EXCIMER LASER SURGERY
• Monovision:
• Dominant eye corrected for distance & Non
Dominant eye for near.
• Difficult to tolerate by most of the patients. Loss of
Contrast and depth perception by the patients.
Limited useful time.
• Multifocal Cornea:
• Excimer Laser reshapes the cornea and alters the
way light rays enter the eye. Hence called as
PRESBYLASIK.
• Both eyes see near & distance.
• Temporary solution , Repeatable and/or reversible
44. SCLERAL EXPANSION PROCEDURE
• Based on Schachar theory
• increasing zonular tension by weakening or altering
the sclera over the CB in order to allow for passive
expansion
• Small incisions in sclera close to cornea->4 silicon
bands inserted to tent sclera between band and
limbus ->Increases distance between ciliary muscle
and lens equator ->enhancing ciliary muscle
contraction
• Inconsistent results.
45. • Advantage :Extraocular
No adverse effects on quality of vision
• Disadvantage:Surgical time-40 mins per eye
Bloody surgery
Modest gains in near vision
Does Not Restore Accomodation
46.
47.
48. LASER ASSISTED PRESBYOPIA REVERSAL
(LAPR)
• Infrared Erbium:YAG delivered through a fibre contact tip
• 4 fornix based peritomies ->Ablations applied in scleral tissue
0.5mm posterior to the limbus to 80% thickness ->Peritomy
sites closed with bipolar forceps.
• complications :Microperforations
Conjunctival cysts
Iris atrophy
• Advantage :Extraocular procedure.
Surgically easy
No adverse effects on vision
• Disadvantage:Variable benefit to near vision
Regression
Expensive laser
50. PHAKIC INTRAOCULAR LENSES
• Lenses inserted over the iris/under the iris without
removing the natural Lens.
• Advantage :reversibility
51. MULTIFOCAL IOL
• Multiple zone IOLs placed after removal of lens.
• Diffractive multifocal IOL :
• Near & distant correction put in each concentric rings Using
diffraction optics with the principle of wave optics.
• Anterior surface - convex
• Posterior surface -stepped with step h8 in the range of wave
length of light.
• Diffraction from these rings produces waves in phase & in 2
diffractive orders,discrete optical foci & equal intensity.
• 82% light of which 41% 4 near n 41% 4 distance.
• Disadvantage:
• present more than one image to the retina at the same time
-> reduction in contrast ,Abberrations ( glare n halos) .
52. Refractive IOL /bull’s eye IOL
• 2 ZONE IOL’S
• Central (2mm) near vision segment surrounded by a distant
vision segment.
• ANNULUS TYPE IOL’S
• Central segment has a distant vision segment n near vision
ring outside it in turn surrounded by distant segment.
REZOOM TECHNIS RESTORE
53. Disadvantages of MIOL
>1 image presented to the retina at the same time .
• reduction in contrast
• Abberrations ( glare and halos)
• Pupil size may be an issue
54. ACCOMMODATING IOL’S
• mimic a juvenile lens - changes in shape by anterior movement
and dioptic power when the ciliary muscle contracts
• Advantage :reduction in contrast sensitivity–n/l.
:corrects near, intermediate and distance
:Abberrations -nil
• Mechanism
• optic shift principle :Has hinges at the lens haptic juncture.
:optic lie against vitreous face.
:ciliary muscle contraction-> vitreous
pressure & aqueous pressure.
: 1D power generated for 0.6 mm
movement .
• Dual optics : 2 lenses :↑ +ve a.lens & -ve p.lens .
seperated by spring like haptics .
:unaccomodated :2 lenses close 2 each other.
:accomodation:a. shifting of +ve lens.
