2. Presbyopia :
Greek word meaning "Old Eyes"
It's not an error of refraction but a physiological
insufficiency of accomodation due to reduced amplitude,
leading to progressive fall in near vision.
Begins between 40 and 45 years of age
3. General insight on :
1. Accommodation:
Its a mechanism by which the eye changes refractive
power by altering the shape and position of its
crystalline lens.
It's a process by which our eyes can focus diverging rays
coming from a near object on the retina inorder to see
clearly.
5. Near point / Punctum Proximum
The nearest point at which small objects can be seen
clearly is called near point.
Far point /Punctum Remotum
The farthest point at which object can be seen clearly is
called Far point
Range of Accommodation :
Distance between far point and near point
Amplitude of accommodation (A)
Difference between diopteric power needed to focus at
near point ( P) and to focus at far point (R)
A = P-R
6.
7. Duanne suggested the following equation for relation of
age ( in years) to accommodation (A)
A = 15 -0.25 ( Age)
8. In an emmetropic eye :
Far point is at infinity
Near point varies with age:
7 cm at 10 years
25 cm at 40 years
33 cm at 45 years
Thus the amount that the eye can alter it's refraction is
greatest in childhood and decreases slowly as the age
advances untill its lost after the middle age.
9. Calculation:
At the age of 10 years , amplitude of accommodation=
Diopteric power for near point - Diopteric power for far
point
100/7 - 100 / infinity
Therefore Amplitude of Accommodation at the age of 10
years : 14
10. Since we usually keep the book at 25 cms while reading
, so we can ready comfortably upto the age of 40 years.
After 40 years near point of accommodation recedes
beyond the normal reading range
This condition of failing Near vision due to age related
decrease in amplitude of accommodation or increase in
Punctum Proximum is called Presbyopia
11. Causes of Presbyopia:
1. Age related changes in lens include:
■ Decrease in elasticity of lens capsule
■ Progressive increase in size and hardness of lens,
which is less easily moulded.
Causes of premature Presbyopia include:
■ Uncontrolled hypermetropia
■ Premature sclerosis of crystalline lens
■ Generalized debility causing Presenile weakness of
ciliary muscles
12. Clinical features:
Symptoms of Presbyopia develop when the amount of
amplitude required to focus at near exceeds more than
half of total amplitude of eye.
13. An undercorrected hypermetrope and chronically under-
corrected myopia will both develop presbyopic symptoms
earlier than an emmetropic patient.
Difficulty in near vision:
Initially occurs in dim light/evening and later even in good
light. Finally near work becomes impossibility.
Asthenopic symptoms:
Due to fatigue of ciliary muscles on doing near work
Intermittent diplopia:
Can develop at near due to inter- relationship between
accommodation and convergence
14. All symptoms of Presbyopia are aggravated by fatigue,
illness, fever or other debilitating conditions.
15. Management of Presbyopia:
1. Optical correction of Presbyopia:
By supplementing accommodation with convex lens of
appropriate power, required for a clear and comfortable
near vision.
The difference between the distance correction and
strength needed for near vision is called as the ADD(
PRESBYOPIC ADD)
16. Addition Determination can be done by following
methods in routine:
1. Age based
2. Measuring the amplitude of accommodation
17. 1. Age based :
Since amplitude of accommodation is age dependent
the presbyopic addition can be estimated arbitrarily
based on patients age
Hoffsetter's age based Add:
The estimations are strictly the starting point and do need
to adjust for particular demands
18. After the add is determined the range is tested, that
is move the chart further and closer reading the smallest
line visible.
This range should coincide with the required working
distance
If the patient desires near range away reduce by 0.25 D
steps and if closer range is desired then increase in
0.25D steps.
19. 2. Measure the amplitude of accommodation:
Method employed is Dodder's or duanne's method
The patient reads the near vision chart (the
smallest line visible) and the chart is brought closer till
the print blurs.
This punctum proximum is converted in diopters
( eg 20cm = 100/20 = 5 Diopters.)
20. Based on Amplitude the ADD is calculated.
Determine NPA .
Eg. If it is 50cms.
The Amplitude of accommodation is 2 Diopters
Keep 1/3rd in reserve for comfort so the available
accommodation is 1.33 .
If the patient desires to read at 33cms.He needs 3.0
diopters(100/33) .
Thus the extra add required is 3 - 1.33 i. e 1.67 Diopters
21. Adjustment of working distance:
The power of PRESBYOPIC add should be adjusted by
taking into consideration the working distance required
by a particular patient and the remaining amplitude.
Eg . At the age of 40 with only 3D total amplitude left, the
following ADDS give variable working distance and leave
comfortable (1/3rd of accommodation ) in reserve
• +2.5 D = 25 cm
• +1.5 D = 33 cm
• + 1 D = 40 cm
• + 0.5 D = 50 cm
22. Inmportance of working distance and individualization
of ADDS:
Eg 1. A tall person habitually holds the book away to
read, so may require lesser addition to have comfortable
range further away
Eg2. Patients with nuclear cataracts shift towards myopia
for distance They are used to higher plus for near may
not accept reduced additions.
23. ADDS for intermediate distance:
As the ADD increases and the amplitude of
accommodation decreases the range of clear vision also
decreases.
Thus strong reading adds which limit the range of clear
normal vision to a small area very near to the patient
are a common cause of patient dissatisfaction
24. Scenario
45 year old emmetropic patient works at a distance of
40 cm. His amplitude of accommodation is 3.5 D and is
given reading glasses of 0.75 D bilaterally.
His range of clear vision through these glasses begins at
1.33 m ( 1/0.75 ) to 0.24 m ( 1/3.5+0.75)
25. The same patient reaches 60 years of age with his
amplitude of accommodation only 1 D. To read
comfortably and clearly at 40cm an add of + 2D is added.
His range of clear vision now begins at 0.5 m(1/2) and
extends to 0.33 m ( 1/(2+1))
26. So this emmetropic patient can see clearly at distance
and at near but his intermediate distance is hampered.
So an additional correction for this intermediate distance
may be required. These are generally one half of near add.
Thus our patient can now see the intermediate distance
from 1m to 0.33 m
27. Basic principles of PRESBYOPIC correction:
• Find out refractive error for distance at first and correct
it .
• Find out PRESBYOPIC Add required to each eye and
add it to distance correction
• The PRESBYOPIC ADD prescribed should leave 1/3rd of
accommodation in reserve.
• Near point should be fixed by taking due consideration
of patient's profession
• Weakest convex lens that the individual requires to see
clearly should be prescribed. Overcorrection avoided
• An additional correction for intermediate distance to
be taken into consideration
28. Following spectacles can be prescribed :
1. Single vision reading glasses :
Suited for those with no Distance refractive error.
2. Bifocal glasses
3. Trifocal glasses
4. Progressive focal OR Multifocal glasses
29.
30.
31. Contact lenses:
All the patients who were wearing contact lenses earlier
when they fall into PRESBYOPIC category will never
prefer to wear glasses
Monovision contact lenses:
The dominant eye is fitted with contact lenses for
distance and non dominant eye for near
Advantages:
Cosmetic appearance
Advisable in professions like librarian, Tv news reader etc
Disadvantages:
small degrees of stereopsis and contrast loss present
32. Bifocal contact lens
1. Alternating bi- focal :
Similar to bifocal spectacle lens
2. Diffracting bifocal:
It has invisible rings and can be distance center or near
center.
Modified mono-vision:
One eye corrected with contact lens of distance power
and other eye with bifocal contact lens.
34. Corneal procedures:
1. Monovision LASIK and surface ablations (PRK, LASEK,
EpiLASIK)
Monovision has been used to compensate for presbyopia
by optically correcting one eye for distance vision and the
other eye for near vision
The amount of target refraction in monovision remains
controversial. Some authors suggest correcting up to
–2.50 D, whereas others suggest not exceeding –2.00D
35. Success rates for monovision refractive laser
correction have been reported to be high (72 to 92%)
( acc to Farid M, Steinert RF. Patient selection for
monovision laser refractive surgery. Curr Opin
Ophthalmol. 2009;20:251–4.)
Disadvantages:
This strategy induces Anisometropia with consequent
reduction in binocular acuity and stereopsis
36. PRESBYOPIC excimer laser ablation:
It is to create Multifocal profiles on cornea by using
excimer laser
Alio et al. reviewed three different approaches that
have been used for corneal multifocality: transitional
multifocality, central presbyLasik (center for near) and
peripheral presbyLasik (peripheral cornea for near) and
concluded that although central
presbyLasik creates a bifocal cornea, the other
techniques inrease the depth of focus based on the
ablation of the peipheral cornea
38. RECENT ADVANCES:
New proprietary ablation pattern (Supracor, Bausch and
Lomb/Technolas, Munich, Germany) was applied using a
profile that steepens the center of the
cornea to create hyperprolate shape resulting about 2D
near addition with controlled higher order aberrations
39.
40. Presbyopic femtosecond laser ablation (Intracor)
Femtosecond laser pulses applied in a concentric ring
fashion inside the corneal stroma were able to induce
changes in the corneal shape without cutting a flap
41. Procedure :
In this proprietary procedure, the pattern of laser delivery
is entirely intrastromal, without impacting the
endothelium, Descemet’s membrane, Bowman’s layer, or
epithelium at any point throughout the operation,
creating a central steepening of the anterior corneal
surface
42. Advantages:
No epithelial dissruption
No pain and inflammation related to absence of
epithelium
Quick recovery
No significant regression of visual acuity or further
corneal steepening occurred during the follow-up period.
43. Disadvantages:
Reduction of mesopic contrast sensitivity
Increase of glare sensitivity
possible consequences on night driving ability should be
discussed with the patients prior to treatment
44. Conductive Keratoplasty:
It is based on radiofrequency energy delivered through a
fine needle tip that is inserted into the peripheral
corneal stroma in a ring pattern.
A series of spots (8-32) are placed in up to three rings of
6-, 7-, 8-mm optical zones in the corneal
periphery.
The shrinkage of collagen between the spots
creates a band of tightening, which results in steepening
of the central cornea
45.
46. It is applied as a monovision procedure in the non-
dominant eye of presbyopic individuals
Advantages:
Minimally invasive
Office procedure
Cost - effective
Although satisfactory NUCVA was reported initially,
significant regression of refractive and keratometric
effects of CK has been observed over short-, mid- and
long-term follow up period, limiting the usage of this
procedure.
48. Available ones are (Kamra, Acufocus Inc, Irvine, CA,
USA)
Principle:
Increases the depth of field using the pin-hole effect to
restore near and intermediate visual acuity without
significantly affecting distance vision
Kamra Inlay:
49. It's placed in the non dominant eye.
Advantages:
Increases depth of field
Recent advances:
The Kamra inlay implantation can be combined
with LASIK improving near vision with a minimal effect
on distance vision, resulting in high patient satisfaction
and less dependence on reading glasses according to a
paper by Tomita et al
50. 2. Space-occupying inlays:
These create a hyperprolate cornea
(Raindrop, Revision Optics, Lake Forest, CA, USA)
Raindrop or hydrogel Corneal inlay
51. In the first published paper in a peer-reviewed journal,
Garza et al. concluded that the hydrogel corneal inlay
improved uncorrected near and intermediate visual
acuity in 20 patients with emmetropic presbyopia, with
high patient satisfaction and little effect on distance
visual acuity at 1 year postoperatively.
52. 3. Refractive annular addition lenticules:
These work as bifocal optical inlays separating distance
and near focal points
(Flexivue Microlens, Presbia, Irvine, CA, USA).
53. A great advantage of the corneal inlays is their
potential reversibility
55. 1. Multifocal IOLs:
Principle : Work on refractive and diffractive technology.
can optically restore some reading vision, but reading
glasses still have to be used for some tasks
Disadvantages:
Nocturnal glare
Reduced Contrast sensitivity
Implantation of a Multi-focal IOL is a contra - indication
for holding a private or commercial pilot license and in
military services
56. 2. Accommodative IOL:
Current accommodative IOL designs have either single
double lens systems that are based on the “focus shift”
principle.
Theoretically, the contraction of the ciliary muscle moves
the optic anteriorly, thereby increasing the
dioptric power of the eye
But several studies have disapproved the above principle
57. SCLERAL PROCEDURES:
1. Anterior Ciliary Sclerotomy:
Anterior ciliary sclerotomy is based on Schachar’s theory
and involves making radial incisions in the sclera
overlying the ciliary muscle.
According to this theory, radial sclerotomies allow
expansion of the sclera overlying the ciliary body,
increasing the space between the lens equator and the
ciliary body.
This may place more resting tension on the equatorial
zonules, allowing for increased tension to develop
during ciliary muscle contraction.
58. 2. Scleral Spacing procedure using PRESVIEW scleral
implants:
The PRESVIEW implant is inserted in scleral tunnel
placed posterior to equator.
The effect of the implant is to allow the lens greater
movement of accommodation
59.
60. Scleral ablation with :
1. Erbium ( Er ) : YAG Laser: being studied in the clinical
trials
2. The laser Ace procedure:
a) The three critical zones of significance as measured
from the anatomical limbus;
b) Restored mechanical efficiency and improved
biomechanical mobility (procedure objectives).
61. Visiolite Erbium : Yag laser used to ablate 600micrometre
spots in sclera which are presumed to free the ciliary
muscle contract normally
The spots are delivered in a diamond matrix pattern of 9
laser spots into each oblique quadrant
This effectively increases the focal power and focal depth
Currently this procedure is in stage 3 clinical trial
62. References :
1. Theory and Practice of Optics and refraction AK
Khurana 2nd edition
2. Clinical Optics 3rd edition A R ELKINTON
3. AAO 2020-21 refractive surgery
4. Cornea - DOS articles Volume 20
5. Refractive Surgery - Kanski's Clinical Ophthalmology
9th edition
6.Hipsley, A., Hall, B. & Rocha, K.M. Scleral surgery for
the treatment of presbyopia: where are we today?. Eye
and Vis 5, 4 (2018)
