The Retina
Chat Highlights
May 15, 2002

Norma Devine, Editor

On Wednesday, May 15, 2002, Dr. Brian Connolly, a retina specialist at Wills, and the glaucoma chat group discussed "The Retina."

Moderator:  Good evening, Dr. Rick and Dr. Connolly.   

Dr. Rick Wilson:  Good evening, everyone.  Dr. Connolly is a retina specialist at Wills and has consented to answer your retina questions with or without reference to glaucoma.  We appreciate his taking time from a busy schedule to be here.

Moderator:  Glad you could join us, Dr. Connolly.  Before we start, can you tell us a little about yourself? 

Dr. Brian Connolly:  I'm a member of the Wills Retina Service.  I practice both at Wills Eye Hospital and Lankenau Hospital,  primarily.  I did both my ophthalmology residency and retina fellowship at Wills.  I also completed an MD with distinction in research at the State University of New York (SUNY), Stony Brook. 

Moderator:  Thank you.  Dr. Connolly, what is the retina and what is its function?

Dr. Brian Connolly:  The retina is a paper-thin tissue in the back of the eye.  Its function is similar to film in a camera or the sensor in a video camera.  The image that you are regarding is focused on the retina, converted into a neurologic impulse, and finally is sent to the brain.

P:  I have found that most glaucoma doctors prefer not to handle retina or cornea problems.  Why is that?    

Dr. Brian Connolly:  As subspecialists, we believe in providing the highest level of care within our specialty.  It is hard to stay current in one specialty, let alone all of ophthalmology.  I would venture to say that your specialist feels the same way.

P:  Doctor Connolly, I'm 23-years-old, and I have lattice degeneration (asymptomatic, no holes) and myopia ( -6.00).  Last year I had a prophylactic treatment with laser photocoagulation.  Does this treatment really reduce the risk of retinal detachment?

Dr. Brian Connolly:  Lattice degeneration is a condition in which the peripheral retina is thinned and prone to tears (rips).  Tears can lead to detachments.  Several years ago, we would have routinely treated such tears with laser or cryo.  Now (in part, due to Dr. Norman Byers' work) we just observe lattice in most patients.  In the fellow eye of a retinal detachment, we generally do laser treatment.  This reduces, but does not eliminate, the risk of tears.

P:  I had two trabs (trabeculectomies) and a cataract operation.  When the intraocular pressure in my left eye increased, my glaucoma specialist asked a retina specialist to see if I would have enough room for a shunt, if I needed one.  Is it always the domain of a retina specialist to make that determination? 

Dr. Brian Connolly:  Were they considering a pars plana tube shunt or an anterior segment tube shunt?

P:  They didn't say.  Does it make a difference?  

Dr. Brian Connolly:  Retina specialists are frequently involved with pars plana tube shunts, because those kinds of shunts require incisions into the pars plana.  Generally, a limited vitrectomy is carried out, and the tube is placed into the back of the eye in the vitreous cavity.

P:  What is the "pars plana?"

Dr. Brian Connolly:  The pars plana is a tissue that lines the front of the eye just anterior to (in front of) the retina.  It is continuous with the retina, but does not have any light perception.

Dr. Rick Wilson:  Brian, you seem to have everything well in hand.  I'll leave you to chat with our virtual community and greatly appreciate your being here to help us.

Dr. Brian Connolly:  Goodnight, Rick.

P:  What level of intraocular pressure predisposes a patient to retinal vein occlusion (RVO)?  What are the symptoms and what is the treatment for RVO?

Dr. Brian Connolly:  Technically, 15 mm Hg to 16 mm Hg, but I'm not sure that the data are very tight for that.

P:  Doctor, 15 mm Hg to 16 mm Hg are close to the average IOP.  Isn't the risk higher at 30 mm Hg or so?

Dr. Brian Connolly:  I didn't mean to mislead you. I like to see patients who have a venous occlusion in one eye keep an intraocular pressure of 15 mm Hg or less in the fellow eye, if possible.  The higher the pressure, the greater the relative risk.  Again, the evidence is a little shaky for this.

P:  Can anything be done about wrinkles in the retina a year after the IOP rose from 2 mm Hg to 10 mm Hg?  

Dr. Brian Connolly:  I'm assuming that you had hypotony maculopathy.

P:  Yes.

Dr. Brian Connolly:  Before answering that question, I'd want to get an ocular coherence tomogram (OCT) to see if there is an epiretinal membrane.  Nonetheless, the treatment is not for many patients.

P:  What are macular puckers and epiretinal membranes? 

Dr. Brian Connolly:  An epiretinal membrane forms when a layer of abnormal tissue grows on the surface of the retina and causes a wrinkle or a pucker.  If an epiretinal membrane is present, the membrane can be surgically peeled in order to improve the vision.

P:  What are the risks of peeling an epiretinal membrane?

Dr. Brian Connolly:  As with any eye surgery, infection and hemorrhage can occur.  Also, the removal of the membrane may not improve the visual acuity.  However, if the membrane is recent in onset, more than 9 of 10 patients see better.  Very few have less vision than at the outset.

P:  What if no membrane is present?  

Dr. Brian Connolly:  If no membrane is present, a slightly higher IOP can help; but if the glaucoma is severe, that may not be an option.

P:  Which is better to repair a detached retina,  pneumatic retinopexy gas bubble or scleral buckling? 

Dr. Brian Connolly:  There is not a "correct" answer.  Pneumatic retinopexy is the least invasive way to repair a retinal detachment.  Nonetheless, it has a single operation success rate of 70 to 80%.  Scleral buckling has a single operation success rate of 95%.

P:  How common is it for patients to see floaters?  

Dr. Brian Connolly:  Exceedingly common.  A shower of new floaters is more specific for a retinal tear or detachment. 

P:  How many floaters are actually caused by retinal problems?

Dr. Brian Connolly:  For a sudden shower of new floaters, many.  If there is a vitreous hemorrhage present, 70% of patients have tears in the retina.  On the other hand, some floaters are like old friends that pop up from time to time.  These are not often serious.

P:  Should even "old friends" floaters be checked out if you have severe glaucoma?

Dr. Brian Connolly:  Yes, at least once.  You might not notice a retinal detachment until fairly late if you have visual field loss from glaucoma. 

P:  How dangerous is retinal detachment in a child?

Dr. Brian Connolly:  A retinal detachment in a child can lead to amblyopia.  When straight edges are viewed, they are distorted.

P:  Why are aphakic patients at a higher risk for retinal detachment?

Dr. Brian Connolly:  Aphakia means the lens in the eye has been removed and there was no replacement.  The vitreous traction probably contributes to the retinal tears that lead to detachments.

P:  When repairing a retina tear with a laser, how do you determine how much power to use? 

Dr. Brian Connolly:  The power needs to be adjusted for each patient.  The tissue changes color in response to the appropriate power.

P:  Can intense squinting cause a retinal tear, detachment or vein occlusion?

Dr. Brian Connolly:  No, no and not likely.

P:  I had sub-choroidal detachments after shunt surgery.  Does this condition heal by itself? 

Dr. Brian Connolly:  If the pressure is low after surgery, swelling of the choroid can occur and distort the peripheral vision.  This often improves with time.  Also, hemorrhage can occur at the time of surgery (or after) and cause painful loss of vision.  This often requires surgery.

P:  I had a trabeculectomy, then cataract surgery, and then I had a retinal tear.  Dr. Murphy in Halifax, Nova Scotia, Canada, performed the retina operation.  I was lucky.  I kept half of my vision. 

Dr. Brian Connolly:  Cataract surgery can sometimes precede retinal tears and or detachments.  I wouldn't be surprised if you got a tear anyway, but it may not have happened as soon in your life without the surgery.

P:  Since I have lattice degeneration and am using a miotic, I guess the lattice degeneration should be mapped to see if there is any progression.  Can that be done?

Dr. Brian Connolly:  An annual exam is appropriate.  Lattice degeneration generally doesn't progress much.

P:  Is using a miotic to control IOP recommended for lattice degeneration?  I'm also aphakic.

Dr. Brian Connolly:  There is an increased risk of retinal tears with the use of a miotic.  This may be synergetic with lattice.  [Editor's Note: When the combined effect of the interaction of two or more agents or forces is greater than the sum of their individual effects, it is said to be synergetic.]   Being aphakic is an additional risk factor for retinal detachment.  I'd see if any alternative medications would control the IOP.

P:  What are the symptoms of retinal vein occlusion (RVO) and how is it treated?

Dr. Brian Connolly:  RVO is a stroke or an occlusion of a venous blood vessel in the back of the eye.  Traditionally, laser treatment is useful for branch vein occlusion (BRVO).  Surgical sheathotomy can occasionally help BRVO's. Central rentinal vein occlusion (CRVO) is less treatable.  CRVO can be treated by relieving the tension on the sclera around the optic nerve by cutting it surgically, but the experience is limited to fewer than 100 patients worldwide.

P:  Can branch retinal vein occlusion resolve on its own?  What are the symptoms?

Dr. Brian Connolly:  BRVO often improves on its own. CRVO may or may not.  Ischemic CRVOs have a poor prognosis and can lead to neovascular glaucoma.

P:  What is the difference between choroiditis and retinitis?

Dr. Brian Connolly:  Both involve tissue inflammation.  Often they can overlap.  Choroid and retina are two distinct tissues that may be inflamed.

P:  What kind of retina research is being conducted?  

Dr. Brian Connolly:  The retina is a hot research topic.  The two main areas of research right now are macular degeneration and diabetic retinopathy.  

P:  Will we see more bionic retinas in the future and more bionic eye parts? 

Dr. Brian Connolly:  The first eye transplant has yet to happen.  Nonetheless, the subretinal chip has actually benefited a small group of patients who have a very specific disease.

P:  Doctor, you just used the specific words, "eye transplant."  Is that apt to happen?  A whole eye with its millions of nerves being reconnected somehow?  Is that even on the drawing board anywhere?

Dr. Brian Connolly:  I would never say never.  Nonetheless, there are huge hurdles that have not been cleared.

Moderator:  What can you tell us about the bionic retina?  Isn't that what Stevie Wonder had implanted?

Dr. Brian Connolly:  No.  Stevie Wonder did not have that.  He met with some doctors at Johns Hopkins who did not feel he was a candidate.  The rest is urban legend.  There is a silicone chip that is being researched.  About six patients have had a subretinal chip implanted for retinal degenerations.  They got reasonable vision (20/60 was the best) with a tiny star-shaped field of vision.

P:  What do you think about all the vitamins and minerals that are supposed to be good for the retina?  I hear kale is good, too.

Dr. Brian Connolly:  The only clearly proven benefit is for age-related macular degeneration (ARMD).  Select patients benefit from vitamins A, C, E, zinc and copper.  High doses of vitamin A may help certain types of retinal degeneration.  

Moderator:  Thank you for your time, Dr. Connolly.  You did a great job.  

Dr. Brian Connolly:  Thanks for all of your attention.  Good evening.

End of highlights for May 15, 2002.

On May 22, Dr. Rapuano discussed "The Cornea" in the Chat room. Click here for highlights of that meeting.

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