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Top-Ten of the 2003 Pan-American Glaucoma Society Meeting (PAGS)
March 28th, 2003, San Juan, PR, USA
Eugenio Maul
The PAGS meets every two years preceding the Pan-American Congress of Ophthalmology. This year's meeting, Perspectives and Practicalities: Glaucoma for the Comprehensive Ophthalmologist and Subspecialist, was very well attended despite the impact on international travel of the recent events in the middle east.
- The review of recent Clinical Trials was one of the top ten. Drs Paul Lichter, Donald Budenz and Paul Palmberg analyzed the impact of these trials on clinical practice. CIGTS evaluated the outcome of initial treatment with medicine versus surgery in newly diagnosed glaucoma patients. Both treatment arms were effective in preventing the progression of visual field damage. Pressure levels were reduced by 48% in the surgical arm and 35% in the medical treatment arm. The data and safety monitoring committee expressed no issue for initial surgery in the management of newly diagnosed glaucoma; however, medical therapy yielded a better quality of life than surgery. In this study 50% of patients had IOP below 18 in 100% of follow-up visits.
- OHTS identified a group of ocular hypertensive patients at a particular level of benefit to prevent damage from glaucoma with IOP-reducing medication depending on risk factors such as IOP, age, central corneal thickness (CCT), and baseline cup/disc ratio. The first POAG endpoint was a change in optic disc appearance in 55% of cases. This stresses the point that, when managing ocular hypertensive patients, careful disc observation must be made at baseline and during follow-up, with stereophotographs being taken for comparison and detection of changes for the early diagnosis of glaucoma.
- CCT emerged from OHTS as one more piece in the glaucoma puzzle. A 40-µm decrease in thickness increased the hazard of developing damage by 70% (hazard, the risk factor analysis that compensates for variable follow-up).
- The Early Manifest Glaucoma Trial is the first trial with an untreated control arm to evaluate the effect of IOP reduction, showing significant delay in progression in the treated arm. Risk factors for progression were age, bilaterality, field loss greater than 4 dB, and pseudoexfoliation, etc. Of particular concern in this study was that treatment with betaxolol and laser could not delay progress in 45% of patients treated, although an IOP reduction of 25% was maintained throughout follow-up.
- A higher risk of cataract after glaucoma surgery is well known. Recent RCT has demonstrated a higher risk of cataract with medical treatment for glaucoma. In EMGT, the rate of nuclear cataract during follow-up almost tripled that of the control group. In OHTS, cataract surgery rates were 6.4% in the medication group versus 4.3% in the observation group.
- A hypertensive phase, a spike in IOP after drainage devices between one and eight weeks, occurs after valved and nonvalved implants. It predicts failure in about 70% of cases. A suggestion was made by Dr. Anne Coleman to treat this pressure rise with aqueous supressants as soon as IOP reaches the early teens. There is a possibility that the IOP control might remain dependent on aqueous suppressants.
- Kissing choroidals, once an obligation for drainage, can be treated succesfully by pressure patching, as suggested by Dr. Anne Coleman. Sinequiae of opposing faces in kissing choroidals have rarely been observed. Excessive inflammation or a flat anterior chamber continue to justify drainage of giant choroidals.
- In many Latin-American countries, the cost effectiveness of timolol is not matched by prostaglandin analogues which may exceed the cost of nonselective beta blockers by five times (Dr. Fernando Gomez, Colombia). In under-developed countries, up to13% of the monthly budget of families with a member affected by glaucoma goes on glaucoma medication. Generic drugs for glaucoma in Latin America may come in bottles that produce a drop that is up to 30% larger in volume, with a signifficant effect on cost and side-effects (Dr. Joao Prata, Brasil).
- Glaucoma with a previous history of cyclophotodestruction or caused by uveitis, represents a risk factor for chronic hypotony after drainage devices. In these cases, a valved implant might be a preferred indication.
- Nonperforating glaucoma surgery is a treatment in the development stage. Long-term success rates and indicators of safety are not yet available. In addition, the learning curve is a significant factor and is different for each of the nonperforating techniques (Dr. Ana Sanseau, Argentina).
