Physiological Impact of Ageing

Part II Ocular Changes

Eyelids

• progressive loss of tone and bulk.

• Loss of tonus, reduced movement, reduced palpebral aperture (ptosis), decreased lid tension.

• Changes in astigmatism with age.

• More difficulty in lid evertion, greater CL comfort?, more difficulty getting CLs out?

• Xanthelasma (xanthoma)

raised yellowish plaques found on the upper and lower lids.

common in elderly women

can be associated with diabetes and ↑ blood LDLs

Eyelids

• Corneal shape changes - from with to against-the-rule astigmatism.

• Corneal fragility increases with age.

• Corneal sensitivity halves by 80 (esp. 40+) - easier CL wear, but possible greater problems (more

regular after-care)- greater with arcus senilus?

• Endothelial changes (cell density dec., increased polymegathism & pleomorphism)

Cornea

Arcus Senilis

• lipid infiltration of the peripheral cornea that iscommonly seen in the elderly

• characterised by being separated from the limbusby a narrow line of comparatively clear cornea.

• asymptomatic and has little consequences for vision

• if seen in Pxs < 40 can indicate ↑ blood LDL level

Conjunctival ageing changes

• Reduced arterial oxygen concentration to Reduced arterial oxygen concentration to conjunctiva - less available to cornea? And conjunctiva - less available to cornea? And increased overnight swelling with CLs?increased overnight swelling with CLs?

• Pingueculae more common with age. Can lift the Pingueculae more common with age. Can lift the lids away from the underlying conjunctiva - local lids away from the underlying conjunctiva - local area of drying and vascularisation.area of drying and vascularisation.

PingueculaePingueculae

PingueculaePingueculae

• age related change of the conjunctiva

• associated with prolonged exposure to sunlight,wind, dust etc.

• due to hyaline infiltration and degeneration of the elastic sub-mucous tissue.

• occurs near the limbus in the palpebral apertureits apex points away from the cornea.

Pterygium

Concretions

• Minute hard, yellow spots in the palpebral conjunctiva.

• due to the accumulation of epithelial cells and mucous

• can lead to abrasion of the cornea and persistentforeign body sensation in the eye.

Tear film changes

• Decreased tear film stability (NIBUT).Decreased tear film stability (NIBUT).

• ? No real change in tear volume.? No real change in tear volume.

• Several drugs tend to reduce tear production Several drugs tend to reduce tear production & many are increasingly used with age.& many are increasingly used with age.

• Sxs of ‘dry eye’ may not always be elicited Sxs of ‘dry eye’ may not always be elicited from older Pxs - reduced corneal sensitivity, from older Pxs - reduced corneal sensitivity, and acceptance of this as ‘normal’ for age and acceptance of this as ‘normal’ for age etc. etc.

Pupil size changes with age

Dark adapted eye

Light adapted eye

Pupil size changes with age

• Pupil gets smaller with age.Pupil gets smaller with age.

• Increases depth of focus, range of near Increases depth of focus, range of near vision, vision, ↓↓ retinal illuminance. retinal illuminance.

• ? Due to atrophy of dilator muscle fibres and ? Due to atrophy of dilator muscle fibres and inc. rigidity of iris blood vessels.inc. rigidity of iris blood vessels.

• No change with gender, Rx and iris colour.No change with gender, Rx and iris colour.

• Greatest age changes at lowest luminances Greatest age changes at lowest luminances (mesopic 7 to 4mm, photopic 5 to 3mm)(mesopic 7 to 4mm, photopic 5 to 3mm)

Anterior Chamber changes

• The anterior chamber depth dec. with age due The anterior chamber depth dec. with age due to the increase in size of the lens.to the increase in size of the lens.

• (This can reverse in some patients with (This can reverse in some patients with cataract, where lens size can decrease).cataract, where lens size can decrease).

• Leads to increases in IOP with age.Leads to increases in IOP with age.

• Leads to closed-angle glaucoma and need to Leads to closed-angle glaucoma and need to check angles prior to pupillary dilation.check angles prior to pupillary dilation.

Ageing lens changes

• Increased thickness with age (28%, 20-70).Increased thickness with age (28%, 20-70).

• Inc. hardening of nucleus & loss of elasticity Inc. hardening of nucleus & loss of elasticity of lens and capsule - loss of accommodation of lens and capsule - loss of accommodation (zero at 55-60 years).(zero at 55-60 years).

• No need to binocular balance over 60 years, No need to binocular balance over 60 years, no point in measuring amplitude of no point in measuring amplitude of

accommodation for 60+.accommodation for 60+.

Ageing lens changes

• Increased light scatter: inc. cortical layers Increased light scatter: inc. cortical layers and inc. large aggregates in nucleus. Greater and inc. large aggregates in nucleus. Greater problems with glare.problems with glare.

• Increased lens yellowing , i.e., increased Increased lens yellowing , i.e., increased absorption of blue light. Colour vision goes absorption of blue light. Colour vision goes tritanopic with age (+ ? neural component).tritanopic with age (+ ? neural component).

• Fluorophors increase with age. UV radiation Fluorophors increase with age. UV radiation leads to light scatter; UV tints?leads to light scatter; UV tints?

Vitreous changes with age

• Vitreous undergoes liquefaction and Vitreous undergoes liquefaction and shrinkage (syneresis) with age.shrinkage (syneresis) with age.

• Leads to increases in vitreous floaters, Leads to increases in vitreous floaters, increase in PVDs (~60% over 65) and increase in PVDs (~60% over 65) and increases in the prevalence of retinal increases in the prevalence of retinal detachments.detachments.

Posterior Vitreous Detachment

Macular changes with age

• No loss of cones, loss of central rods.No loss of cones, loss of central rods.

• Disorganisation of rods and cones and Disorganisation of rods and cones and lipofuscin accumulation.lipofuscin accumulation.

• Leads to inc. photostress recovery time.Leads to inc. photostress recovery time.

• No change in macular pigment with age. No change in macular pigment with age. Macular pigment is very variable.Macular pigment is very variable.

Macular drusen

• Hyaline deposits between the RPE and Hyaline deposits between the RPE and Bruch’s membrane.Bruch’s membrane.

• ? Due to small areas of hypoxia due to ? Due to small areas of hypoxia due to choriocapillaris age changes - leads to RPE choriocapillaris age changes - leads to RPE malfunction and “spitting out” of collagen malfunction and “spitting out” of collagen and basement membrane material = drusen.and basement membrane material = drusen.

• Distinction between hard and soft drusen.Distinction between hard and soft drusen.

Peripheral retina ageing changes

• Peripheral pigmentary degeneration seen in Peripheral pigmentary degeneration seen in ~20% ~20% of 40+ - hypo and hyperpigmentation.of 40+ - hypo and hyperpigmentation.

• Peripheral drusen.Peripheral drusen.

• Inc. paving-stone degeneration (chorioretinal Inc. paving-stone degeneration (chorioretinal atrophy) - white areas of sclera with overlying atrophy) - white areas of sclera with overlying choroidal vessels - closure of small area of choroidal vessels - closure of small area of

choriocapillaris.choriocapillaris.

Visual pathway changes with age

• No cell loss in LGN.No cell loss in LGN.

• No loss of striate cortex neurons with age.No loss of striate cortex neurons with age.

• VEP changes with age suggest there are VEP changes with age suggest there are functional cell changes with age, perhaps functional cell changes with age, perhaps linked to vascular changes.linked to vascular changes.