prePRESBYOPIA By Sivaraja Rathinavel

Patient's Demographic Data

•Age 43/M

•Occupation: Fisher man

•Come to our camp for screening

History & complaints

• Had a complaint of difficult in near vision.

•General history was normal

RefractionObjective refraction(Auto Refractometer)

Sph Cyl Axis

OD +1.75 -0.75 70

OS +1.50

Subjective refractionSph Cyl Axis BCVA

(D)Add BCVA

(N)

OD +1.00 -0.25 90 6/6 +1.00 6/6

OS +1.00 -0.25 90 6/6 +1.00 6/6

Near vision by reduced snellen VA chart @ 40 cms

Ocular Examination:TLEParts OD OS

Eyelid WNL WNL

Conjunctiva WNL WNL

Cornea Clear Clear

Anterior Chamber Deep/Quiet Deep/Quiet

Iris Normal Normal

Pupil R/R/R R/R/R

Lens Clear Clear

•Hirsh Berg Test : Central

•Extra Ocular Muscle Movement Test Full, Free in all the gazes

External Examination

Diagnosis1.(OU)Compound hyperopic astigmatism 2.Presbyopia

Management• Bifocals prescribed.

•Counseling for regular use of spectacles.

OD OS

Bifocals Bifocals

PresbyopiaPresbyopia is not an error of refraction but a condition of physiological insufficiency of accommodation leading to a progressive fall in near vision.

Etiology

• Age related change in the lens. i.e,decrease in elasticity of lens capsule

•Age related decline in ciliary muscle power

AGE RELATED CHANGES IN

ACCOMMODATION • Tonic accommodation

• Depth of focus

• Accommodative amplitude

• AC/A Ratio

Tonic accommodation

It is due to tonus of ciliary muscle and is active in absence of a stimulus. The resting state of accommodation is not at infinity but rather at an intermediate distance.

Depth of Focus

It is a variation in image distance in a lens or optical system which can be tolerated without incurring an objectionable lack of sharpness in focus.

Amplitude of accommodation

•The amplitude of accommodation represents the maximal accommodative level ,or closet near focusing response that can be produced with maximal voluntary effort in fully corrected eye

•The difference between the dioptric power needed to focus at near point(P) and far point(R) is called amplitude of accommodation.

A=P-R

Hat Amplitude of accommodation

Can Accommodative values based on age

AC/A ratio• The accommodative convergence/accommodation (AC/A) ratio is defined as the amount of convergence measured in prism diopters per unit (diopter) change in accommodation.

• Heterophoric method AC/A =IPD+( n - d)/D

IPD-Inter Pupillary Distance n-Deviation at near d-Deviation at distance

D-Diopters

•Normal AC/A ratio value4:1

TYPES OF PRESBYOPIA •Incipient Presbyopia

•Functional Presbyopia

•Absolute Presbyopia

•Premature Presbyopia

•Nocturnal Presbyopia

IncipientPresbyopia

• The early stage of presbyopia. Symptoms are usually mild and include experiencing difficulty reading very small print.

Functional Presbyopia

• Symptoms have usually developed by this stage and you may find it increasingly difficult to read things up-close or focus on detailed activities.

Absolute Presbyopia

This occurs when the eyes are not capable of focusing on objects and images up-close.

Premature Presbyopia

This form of presbyopia affects people below the age of 40.

Causes:

•Uncorrected hypermetropia.

•Premature sclerosis of the crystalline lens.

•General debility causing pre-senile weakness of ciliary muscle.

Examination

•Objective refraction

•Subjective refraction

•Post mydriatic test

Case example

•A 39 yr old man comes with a complaint of head ache & blurringVision with prolonged reading.

On examination: Vision OU: (6/6)unaided N10@45cms NPA: OU:3cms

Subjective refraction:OU:+0.50(6/6) Add:+1.00N6@30cms

Cycloplegic refraction:OU:+2.00DSPMT:OU:+1.50(6/6)N6with ease@30cms.

Nocturnal Presbyopia

This occurs when people experience difficulty focusing on objects in dull or dim lighting.

eoryTheories of presbyopia

HELMHOTZ THEORY

• This theory attribute all of the loss in accommodation to biomechanical changes in the lens Capsule & lens and none to the ciliary muscle.

• According to this the amount of ciliary muscle Contraction required to produce a unit change in accommodation remains constant with age.

DONDERS DUANE FINCHAM THEORY

• later Duane prove that Helmholtz theory was wrong.

• In his theory he state that The amount of ciliary muscle contraction needed to produce a unit change in accommodation progressively increases with age. thus as one ages, the reduced Amplitude is due to progressive weakening of the ciliary muscle itself.

Theories of presbyopia

Symptoms

• Difficulty in near vision

• Headache

•Fatigue from near work

•Increased working distance

•Need of extra light for reading

Ocular examination

•Visual acuity

•Refraction

•Binocular vision & accommodation

Binocular vision& accommodation

•NRA/PRA

•Positive Relative Accommodation high value ≥ -3.50D Low value -1.50D

•Negative Relative accommodation High value +2.50D

Example:

Approx add:+1.00DNRA:+1.00D PRA:-0.50D

Tentative add=approximate add+(algebraic sum of NRA,PRA)/2 =+1.00D+(+1.00+-0.50)/2 = +1.00D+(+0.25) =+1.25D

continue

•Cover test

•Extra ocular muscle movement test

•Hirschberg corneal reflex test

MANAGEMENT

•Optical correction with spectacle lenses

•Optical correction with Contact lenses

Hofstetter’s table

Hofstetter’s formula

Minimum amplitude= 15.0D-(0.25D* <age in years>)

Mean amplitude= 18.5D-(0.30D*<age in years>)

Maximum amplitude=25.0D –(0.40*<age in years>)

Spectacle as correction

•Single vision lenses

•Bifocal lenses

•Trifocal lenses

•Progressive additional lenses

Spectacles as correction

• Bifocal lenses

•Trifocal lenses

Spectacles as correction

•Progressive additional lenses

Contact lenses as correction

•Bifocal lenses

•Multifocal contact lens

Contact lenses as correction

•Multifocal contact lenses

Contact lenses as correction

•Bifocal contact lenses

THANK YOU