Glaucoma
Reports of phaco reducing

At a glance

• Studies have shown that cataract surgery alone can lower IOP, proportional to presurgical IOP • Combined procedures of phaco & trab/tube shunt for glaucoma pts with compliance issues, requiring chronic steroids, low target IOP, & blebs • Ultimately decision depends on which is worse, cataract, glaucoma, or if they are similar • Studies have shown that cataract surgery alone can lower IOP, proportional to presurgical IOP

After several papers published in 2008 reported that cataract surgery caused intraocular pressure to decrease, more ophthalmologists are considering phacoemulsification has a glaucoma treatment

Neovascular Glaucoma Source: Karl Brasse, M.D., EyeLand Design Network

The practice of performing a combined phacoemulsification and trabeculectomy or tube shunt increasingly is being reserved for patients with glaucoma medication compliance problems, according to ophthalmologists.
One contributing factor in this trend is that reports began to surface that phaco alone could reduce IOP, and in fact, as concluded by Brooks J. Poley, M.D., Bluffton, S.C., and colleagues, “the reduction was proportional to the presurgical IOP. The decrease was greatest in eyes with the highest presurgical IOP.” This paper, published in the May 2008 issue of the Journal of Cataract & Refractive Surgery (“Long-term effects of phacoemulsification with intraocular lens implantation in normotensive and ocular hypertensive eyes”), was one of several reports in from 2008 and 2009 to state such findings.
“I shy away from combining the two techniques in part because some of the data that was presented at both AAO [American Academy of Ophthalmology] and ASCRS [annual meetings] in 2009 show that cataract surgery alone can lower IOP,” said Lt. Col. Herbert P. Fechter, M.D., assistant professor, Uniformed Services University, Atlanta.

Addressing the patients’ needs

Generally speaking, Dr. Fechter said if a patient has mild glaucoma and a cataract, he usually just does cataract surgery in hopes of lowering the IOP as well. But if the patient has elevated IOP, he will do tube surgery first, and then after that problem has been rectified, then he treats the cataract.
Jeffrey D. Henderer, M.D., professor and chair of ophthalmology, Temple University School of Medicine, Philadelphia, adheres to a similar approach. He said when deciding how to treat a patient with a cataract and glaucoma, he needs to decide which is a bigger problem for the patient—the cataract, the glaucoma, or if they are co-equals. The answer to that question determines his treatment approach.
“My belief is that my trabeculectomy works better when unaccompanied by cataract surgery,” Dr. Henderer said. “So, if I can avoid doing cataract, I would like to avoid it, or if I can do the cataract first and then the glaucoma surgery later, I would rather do that.”
Both Drs. Fechter and Henderer acknowledged that the patient’s ability to comply with the glaucoma medication regimen or if the medication is ineffective are an extenuating circumstances that could prompt them to offer combined surgery as a solution.
At the 2009 ASCRS annual meeting in San Francisco, Thomas W. Samuelson, M.D., director, Glaucoma Service, and instructor, ophthalmic pharmacology, Regions Hospital, St. Paul, Minn., and attending surgeon, Minnesota Eye Consultants, Minneapolis, expanded the list of circumstances to include patients that want off medications; patients requiring chronic steroids; a progressive disease that threatens fixation; patients with low target IOP; and patients with pre-existing blebs.
“The biggest benefit of combining surgery is the ease it creates for the patient,” Dr. Henderer said. Combining the procedure also eliminates the possibility of a complication arising in the post-op period after doing a surgery singularly, though he acknowledged this is a rare circumstance that does not influence his decision making.
Another condition in which Dr. Fechter said he will do a combined surgery is unique, indeed.
If a patient has elevated IOP with neovascular glaucoma and a poor view to the back of the eye, and the retinal surgeon wants both the pressure controlled and vision to the back of the eye, then he will consider doing both surgeries at once just because of the timing.
“The retina surgeon needs to see the back of the eye in order to put laser in there, and there is not sufficient time to wait around for the pressure to come down, so I’ll do both surgeries at once under that circumstance,” Dr. Fechter said.

Pseudoexfoliation, phacomorphic glaucoma and phaco

Exfoliation is the most identifiable cause of open angle glaucoma, Dr. Samuelson said at ASCRS. About 44% of these patients develop glaucoma, so it had been common practice to wait on cataract surgery because there is a small pupil, weakened zonules, usually a shallower anterior chamber and more common IOP spikes post-operatively.
But as the recent reports have stated, as the lens ages, it pushes the iris into the angle so that it impedes the flow of aqueous resulting in phacomorphic glaucoma, Dr. Samuelson said. He added that he believes there are several forms of phacomorphic glaucoma including narrow angle, angle closure, and even open angle.
Dr. Henderer said to determine if the patient has phacomorphic glaucoma, first the physician must do a gonioscopy. If then the physician sees a narrow angle, then look at the cataract and determine if it is a thick cataract with a shallow anterior chamber, which could indicate that the patient has phacomorphic glaucoma.
The recent findings of cataract surgery as a step in glaucoma management should cause ophthalmologists to review what once was considered conventional dogma, that being that cataract surgery is more complex in exfoliation so phaco should be delayed until absolutely necessary, Dr. Samuelson said.
“But now we know the lens should come out earlier because not only does waiting make the cataract surgery more complex, but it also exasperates phacomorphic glaucoma and delays the IOP improvement caused by cataract surgery,” he said.
More and more, physicians should be considering cataract surgery prior to trabeculectomy and tube surgery because these two procedures bypass the trabecular meshwork (TM). So any improvement in the outflow from removing the cataract is somewhat lost because the prior surgery has already bypassed the TM.
Though Dr. Henderer pointed out that another reason he tends to err toward performing trabeculectomy first in patients suffering more from that disease is because while rare, there is the possibility of a post-cataract surgery IOP spike that could cause snuff-out syndrome.
“I think the data shows there is a small but statistically significant IOP drop after cataract surgery in a lot of patients,” Dr Henderer said. “If you have phacomorphic angle narrowing or closure, removing the lens can relieve the phacomorphic condition.”
Some physicians who are suspect of phaco’s effect on IOP might say it is just regression to the mean, Dr. Fechter said. As the data is recent, it does have its detractors who question if this is a true finding.
For example, there was the conclusion that in patients with elevated pre-op IOP, there tended to be a greater drop after surgery whereas patients that started in the 10 to 15 mmHg range actually saw a slight increase in IOP.
“So it could just be that we were selecting patients with higher pressure and concluded the cataract surgery brought down these pressures whereas they might have come down without surgery anyway,” Dt. Fechter said.
Cataract surgery is being considered as a treatment for glaucoma, and fewer glaucoma physicians are performing trabeculectomy, Dr. Fechter said. Taking these two statements into consideration, he said he suspects there are fewer combination procedures now than before.

Editors’ note: Drs. Fechter, Henderer, and Samuelson have no financial interests related to their comments.

Contact information

Fechter: 706-651-202, fecther@pol.net
Henderer: 215-707-2374, jeffrey.henderer@temple.edu
Samuelson: 612-813-3600, twsamuelson@mneye.com