Cataracts and the Glaucoma Patient
Chat Highlights
October 9, 2002

Norma Devine, Editor

On Wednesday, October 9, 2002, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Cataracts and the Glaucoma Patient."

Moderator:  Tonight we will be discussing cataracts.  Dr. Wilson, will you  start by describing a cataract?  

Dr. Rick Wilson:  A cataract is an opacity (cloudiness) in the lens in the eye that focuses light on the retina. To help produce a sharp image, the lens must remain clear. 

Moderator:  Are cataracts more prevalent in glaucoma patients who have had previous surgery?  

Dr. Rick Wilson:  Glaucoma is a risk factor for cataracts without any surgeries.  Surgeries just make that tendency worse, especially in the elderly. Cataract is not a risk factor for glaucoma

P:  What is a nuclear cataract and how does it differ from other kinds?

Dr. Rick Wilson:  A nuclear cataract happens in the center, or nucleus, of the lens.  It is the most common type of cataract; the center turns a brownish-green as it get more dense with age.

P:  I have normal-tension glaucoma, cataracts, and 20/50 vision. I suffer from excessive glare, blurred vision,  and have difficulty seeing on poorly illuminated roads.  Are the cataracts or the glaucoma the main cause of these problems?  I don't need glaucoma surgery.    

Dr. Rick Wilson:  The lenses in our eyes grow throughout life.  Since there is little room for them to grow in the eye, the lenses compact and become more dense. That often leads to people becoming slightly more nearsighted as they age.  Your problems sound more like cataract symptoms than glaucoma symptoms.  

P:  Will cataract surgery improve my vision to 20/20?  How reliable is cataract surgery in a glaucoma patient?

Dr. Rick Wilson:  It is possible to return your vision to 20/20 if the cataract is the only thing wrong with your eye.  Cataract surgery should be reliable in the glaucoma patient.  The biggest risk is of an increased IOP (intraocular pressure) in the period shortly after cataract surgery.

P:  Is it true that trauma to the eye can cause cataracts as well as glaucoma?

Dr. Rick Wilson:  Sure, as can inflammation, topical steroid use, and diabetes that is under poor control. 

P:  Are cataracts caused by trauma different from other types?

Dr. Rick Wilson:  Yes, they tend to grow at the back of the lens, the closest to the retina, and are white.  This type of cataract may develop into an entirely white cataract.

P:  If my dad had cataracts and I have glaucoma, will I probably get cataracts, too?

Dr. Rick Wilson:  Everyone gets cataracts if they live long enough.

P:  How can we notice we have cataracts, since they grow slowly?

Dr. Rick Wilson:  Same symptoms that were mentioned above:  blurred or fuzzy vision, glare.

P:  I need to have a congenital cataract removed soon.  I also need to have a capsulotomy, because my capsule is very unstable.  One of my options is to have a contact lens; the other is to have glasses.  I cannot have the intraocular lens because even if the lens is sutured in place my nystagmus could shake the lens loose and cause corneal edema. My glaucoma doctor will only tell me that she does not want me to use the contact lens because it would mess up the trabeculectomy.  I would really like a medical reason.  Could you please tell me why this would not be advisable, if it is not?

Dr. Rick Wilson:  If you have a trabeculectomy, the conjunctiva overlying the site is usually elevated and may disturb the fitting of the lens.  The conjunctiva may also be thin, and trauma from the lens could cause an infection or leak.

P:  Would a glaucoma patient with severe glaucoma, loss close to fixation, and dense cataracts (but no trabs) do better having the cataracts removed by a cataract surgeon with lots of experience or a glaucoma surgeon?

Dr. Rick Wilson:  That depends upon the glaucoma surgeon.  Because of glaucoma, glaucoma specialists are usually very conservative about removing cataracts and wait until well after an uncomplicated patient would have had  cataracts removed.  Therefore, glaucoma specialists are used to tackling dense, hard cataracts, often with small pupils, that making getting to the cataract difficult.  In addition, we often have patients with pseudoexfoliation that weakens the ligaments that hold the lens in the eye securely.  That is a long way of saying that the average glaucoma specialist is usually an adept cataract surgeon and well versed in removing the lens and handling the IOP problems that may result.

P:  A family member had surgery for glaucoma and cataracts. The doctor said he couldn't get an accurate reading of something -- the shape of the back of her eye, perhaps -- and the lens he gave her did not give her very clear vision as a consequence.  Please comment.

Dr. Rick Wilson:  I assume you mean without glasses.  Usually, even if the power of the intraocular lens is slightly off, the eye can be corrected to good vision with glasses.

P:  Before I had my cataracts removed, everything had a yellowish tint. Is that also a symptom?

Dr. Rick Wilson:  Yes, that is the brownish-green I spoke about earlier. 

P:  I have had Type II diabetes for 18 years.  Will this make cataract surgery more risky?  I don't have any diabetes-related eye problems other than glaucoma.

Dr. Rick Wilson:  Probably not.

P:  My understanding is that some types of cataracts cause visual acuity to change more frequently as they develop, resulting in more frequent lens changes.  Which type is that?

Dr. Rick Wilson:  The nuclear cataract causes a myopic or near-sighted shift, resulting in glasses changes every six months or so.  

P:  Can a patient who has had a trabeculectomy have an intraocular lens implanted?  

Dr. Rick Wilson:  Yes.  That's very common.

P:  What can be done for someone whose intraocular lens power is very low (3) to make  surgery safer?  

Dr. Rick Wilson:  Some companies make lenses of any power. The problem usually is that the patient requiring lens powers that low are often very near-sighted, with a thin retina stretched over the inside of the eye.  If there are any weak places, a retinal tear or detachment may result.

P:  Can cataract surgery make wearing glasses unnecessary? 

Dr. Rick Wilson:  Yes. We often aim to make it unnecessary for the patient to wear glasses or perhaps wear just weak glasses.  The patient can be made nearsighted, or farsighted, or perhaps not needing to wear glasses, by changing the power of the lens placed in the eye. 

P:  Is there ever a need to change the artificial lens implants following cataract surgery?  If so, does that pose a problem? 

Dr. Rick Wilson:  An error in the ultrasound measurement of the length of the eye or the measurement of the corneal shape can lead to an error in the power of the intraocular lens.  If that error is large enough, glasses can't compensate for it.  Then a lens exchange may be needed.  Another reason would be inadequate support of the lens where it is placed. 

P:  Both my doctors recommended a trabeculectomy along with my cataract surgery. Is that always done?

Dr. Rick Wilson:  Not always, but it is often done if the patient is using two or more topical medications. 

P:  What do think about the hypothesis that cataracts may be protective against age-related macular degeneration (because they block blue light), and should therefore be removed as late as possible in the patient's life (consistent with acceptable visual acuity, of course)?

Dr. Rick Wilson:  Personally, I would rather see clearly and wear sunglasses to protect my retinas.  Spinach, broccoli, and kale also help. 

P:  I have had a trab and was told that cataract surgery could mess up the trabeculectomy.  If that is the case, should I wait until I can hardly see anything out of that eye before having the cataract removed?

Dr. Rick Wilson:  Yes.

P:  Can an intraocular lens (IOL) improve vision better than prescription lenses?  For example, can an IOL improve corrected vision of 20/70 to 20/20?  

Dr. Rick Wilson:  Usually not.  Intraocular lenses usually don't do as well with contrast sensitivity as natural lenses do.  Although the vision of the patient reading the Snellen chart may be 20/20, the patient may not feel he or she sees as well as before.  

P:  Mine were corrected from 20-200 with very high astigmatism to 20-30 on the chart and I see very well without glasses except for reading.

Dr. Rick Wilson:  Great!  A real success story.

P:  Are most intraocular lenses multifocal nowadays, or do many patients require reading glasses after cataract surgery?

Dr. Rick Wilson:  Only one brand that I know of,  from Allergan Medical Optics, is bifocal. The rest require monovision or glasses for either distance or near.

P:  I thought a single artificial lens could be only for close up or for distance -- not both. In the case of two implants, would they have to be of different focal lengths for perfect sight?  

Dr. Rick Wilson:  Yes and no. With monovision, as was mentioned above, one eye can see clearly for distance, and the other one for near. There are bifocal intraocular lenses, but they are not for everyone.

P:  Is there any possibility of an allergic reaction to the artificial lens or of the body rejecting the lens?

Dr. Rick Wilson:  Not in the usual sense.  Giant cell deposits can form on an intraocular lens, but that is probably not a common type allergic reaction.

Moderator:  Thank you, Dr. Rick.  We learned that there are age-related cataracts, congenital cataracts, cataracts secondary to certain health problems (such as diabetes), traumatic cataracts that develop soon after an eye injury or years later, and cataracts linked to steroid use. 

End of highlights for October 9, 2002.

On October 16, Dr. Wilson discussed "Pediatric Glaucoma" in the Chat room. Click here for highlights of that meeting.

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