H25.041-043 Posterior Subcapsular Polar Senile Cataract

Posterior subcapsular polar senile cataract is a disease characterized by: 

• Peroxidation of lens proteins leading to decreased transparency
• Compression of lens fibers from continued lens growth
• Accumulation of urochrome pigments from amino acid breakdown leading to brunescence
• A gradual, progressive thickening of the lens

Structural Damage to the Eye

• With age, the lens changes in weight, transparency and thickness
• With age, the accommodative power decreases
• Excessive lens thickening can lead to pupillary block and secondary glaucoma (cataract surgery has shown to reduce IOP 4-6 mm Hg and sometimes much more, often eliminating the need to prescribe second medications or any other kind of additional treatment in patients with closed-angle glaucoma

Functional Damage to the Eye

• Blurred vision 
• Decreased visual acuity 
• Glare 
• Myopic shift 
• Monocular diplopia 
• Patients reports seeing shadows in eye or feels their glasses are always dirty and they have to clean them all the time

The main goal of the diagnostic evaluation in a patient with posterior subcapsular cataract is to accomplish the following.

• Evaluate the level of vision impairment and determine if daily activities are affected
• Rule out or make an attempt to quantify comorbidities that could be contributing to reduced vision

Patient History 

Abnormal symptoms generally include the following: 

• Decreased vision
• Increase in glare
• Difficulty in daily task
• Difficulty manuvering around in dim lighting

Senile cataracts are classified into three main types: nuclear cataract, cortical cataract, and posterior subcapsular cataract.

		Nuclear Cataract Results from excessive nuclear sclerosis and yellowing with the formation of central lenticular opacity Nucleus of the lens can become brown or brunescent
Cortical Cataract Result from the ionic lens composition lens cortex and the eventual change in the hydration of the lens fibers
		Anterior Subcapsular Cataract Results from the formation granular and plaque-like opacities in the anterior subcapsular part of the lens

Posterior Subcapsular Cataract Results from the formation granular and plaque-like opacities in the posterior subcapsular portion of the lens

None.  It is important to identify any other abnormalities that could be contributing to loss of functional vision.  If identified, every attempt should be made to quanitfy that effect.  While the existence of comorbidities does not rule out the need for or recommendation of cataract surgery, it is necessary to make as accurate prediction as possible of the resultant postoperative acuity if the patient elects to undergo cataract surgery.

The most common age-related comorbidities to rule out are:

• Macular degeneration
• Diabetic macular edema
• Corneal dystrophies and degenerations
• Glaucoma
• Neurologic disorders

As stated, simply the presence of another cause of functional vision loss does not lessen the value of cataract surgery.  One of the best examples of this scenario would be a patient with advanced cataract and moderate to advanced macular degeneration.  While many physicians concentrate on the macular pathology, elimination of a significant lens opacity can dramatically improve the quality of the patient’s remaining vision.

Surgical Treatments

Tecnis IOL (AMO)

• Provides vision for distance only
• Designed with a prolate surface to introduce negative spherical aberration to decrease or eliminate positive spherical aberrations from the eye
• Design also helps increase contrast sensitivity especially at night

SofPort AO (Bausch & Lomb)

• Provides vision for distance only
• Designed with a prolate surface to introduce neutral spherical aberration, leaving the patient with the normal corneal spherical aberration for their age
• This design does not improve contrast sensitivity
• Design makes the lens less dependent on surgical technique or perfect centration

AcrySof IQ (Alcon)

• Provides vision for distance only
• Designed with a prolate surface to introduce negative spherical aberration to decrease or eliminate positive spherical aberrations from the eye
• This design also helps increase contrast sensitivity especially at night
• Has a transparent yellow color that does not alter the color or quality of the environment when inserted in the eye

2. Multifocal intraocular lens

Crystalens HD (Bausch & Lomb)

• Hinged design allows the lens to change position inside the eye as the patient looks at a near target
• Only FDA approved accommodative lens
• Good distance and intermediate ranges with the lens
• Limited near range (add of 1.50D to 2.00D)
• Patient occasionally to very likely will need reading glasses for small or detailed near tasks

Tecnis Multifocal (AMO)

• Diffractive design with designate zones of near, intermediate and distance
• New design is not affected by pupil size in various lighting conditions
• Shaped to correct for certain high order aberrations which improve the ability to see contrasting objects especially

ReZoom (AMO)

• Designed with alternating refractive zones that correct for either distance or near. Central optical zone corrects for distance, then near and alternating back to distance again
• Good distance, but glare may be an issue at night

AcrySof ReSTOR (Alcon)

• Designed with the principle of apodization or a series of graduated steps that result in diffraction of light at distance and near
• Two adds available (+4.00D and +3.00D)

AcrySof IQ ReSTOR (Alcon)

• Similar to the AcrySof ReSTOR except for new aspheric design helps reduce potential for glare/halos and improves contrast sensitivity

AcrySof Toric (Alcon)

• For patents with small amounts of corneal cylinder (1.00D to 1.50D) limbal relaxations incisions work well with the spherical multifocal lens
• The toric multifocal lens corrects up to 3.00D of cylinder
• Patients with cylinder greater than 3.00D can have the toric multifocal implanted with additional procedure like limbal relaxing incisions or refractive laser procedures to completely correct for the astigmatism

AcrySof IQ Toric (Alcon)

• Similar to the AcrySof Toric except for new aspheric design helps reduce potential for glare/halos and improves contrast sensitivity

AcrySof Natural (Alcon)

• Designed to filter out ultraviolet and high-energy blue light
• Has a transparent yellow color that does not alter the color or quality of the environment when inserted in the eye

It is imperative that the patients primary eye care provider, usually their optometrist, be intimately involved in the decision regarding the proper lens for that patient.  The patients primary eye care provider is more atuned to the patients specific vision needs, the flexibility in their vision/perception system, and the ease at which they adapt to visual change.

1.  Dahl, A.  Cataracts.  MedicineNet.  http://www.medicinenet.com/cataracts/article.htm.  Last accessed November 16, 2014.
2.  Facts About Cataract.  National Eye Institute.  National Institutes of Health.  Sept 2009. https://www.nei.nih.gov/health/cataract/cataract_facts.  Last accessed November 16, 2014.