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Some Glaucoma Highlights from the Joint 2002 Meeting of the American Academy of Ophthalmology and the Pan-american Association of Ophthalmology

October 20-23, 2002, Orlando, FL, USA

Leon Herndon

Bleb-associated endophthalmitis

Seventy-eight consecutive cases of bleb-associated endophthalmitis (BAE) were reviewed. Median post-BAE vision was 20/80, with 17% of eyes having no light perception (NLP). Vitreous isolates included Streptococcus species (32%), Staphylococcus epidermidis (26%), Enterococcus (12%), and Serratia (12%). NLP rates were higher in eyes with positive vitreous cultures and lower in eyes undergoing pars plana vitrectomy. The significant visual morbidity that can occur with BAE and theneed to differentiate posterior involvement (i.e., endophthalmitis) from the more benign localized anterior segment bleb-related inflammation (BRI), was highlighted. When in doubt, it is in the patient's best interest to undergo prompt pars plana vitrectomy with vitreous cultures and the administration of intravitreal antibiotics.

Frequency-doubling versus tonometry

Glaucoma screening was performed on 2104 adults using Frequency-Doubling Technology (FDT) perimetry and the measurement of intraocular pressure (IOP). IOP > 21 mmHg or a FDT (C-20) with > 1 misses triggered further testing that included 24-2 Humphrey visual fields (HVF) and computerized optic nerve evaluation. Three hundred subjects failed screening FDT perimetry; 284 of these subjects subsequently had defects on HVF. Forty-seven (17%) of these subjects had an IOP > 20 mmHg. The false positive rate for FDT (relative to HVFs) was 5% (16/300). Significant optic disc abnormalities were present in approximately 85% of eyes failing HVF. True positive rates were 33% for IOP and 92% for FDT. IOP screening failed to detect more than 80% of glaucomas. The high concordance between FDT and HVF, as well as the presence of optic nerve abnormalities, presents continuing data on the value of FDT for glaucoma screening.

Visual results following pars plana vitrectomy for retained lens fragments

A retrospective review of 48 consecutive eyes with at least six months' follow-up after vitrectomy for retained lens fragments was presented. While early vision was $ 20/40 in 67% of eyes, final acuity was reduced to less than this level in 17% of eyes because of delayed postoperative events. Late retinal detachment occurred in 17% of eyes, while 21% developed chronic glaucoma.

The study stresses the need for long-term surveillance of patients undergoing vitrectomy for retained lens fragments.

Selective laser trabeculoplasty: a new approach to open-angle glaucoma management

Selective laser trabeculoplasty (SLT) was performed on 207 open-angle glaucoma (OAG) or ocular hypertensive (OH) patients with either: lack of medical control, or newly diagnosed without prior therapy. SLT was performed for 90o, 180o, or 360o with the Lumenis Selective 7000 laser. Pressure reduction in the uncontrolled groups was 25.6% for OAG and 33% for OH. In the first-line treatment patients, pressure reduction was 28.5% in the OAG and 29.5% in the OH subjects. SLT success increased as the treatment area increased. However, this was associated with increased postoperative anterior chamber inflammation. The IOP response was sustained during the 26 months' duration of the study. SLT appears to be a viable alternate to argon laser trabeculoplasty in OAG eyes with either medically uncontrolled or newly diagnosed disease.

Plasma homocysteine levels in exfoliation syndrome with and without glaucoma

Plasma homocysteine levels in patients with exfoliation syndrome (XFS) were evaluated. Levels were higher in XFS subjects with or without glaucoma, compared to nonglaucoma controls and to subjects with low-pressure glaucoma. XFS is thought to be a general disorder of the extracellular matrix. The finding of hyperhomocysteinemia in XFS is a potential modifiable disorder, which is associated with systemic vascular disease. Plasma homocysteine is a routine laboratory test that should be performed in patients with XFS.

Analysis of autoantibody repertories in patients with glaucoma

The presence of plasma autoantibioties against the retina and optic nerve was measured in 25 open-angle glaucoma (POAG), ocular hypertensive (OHT), low-pressure glaucoma (LPG), and healthy volunteers. Patterns of OHT patients were similar to those of the normal controls. POAG was most different from controls for retinal antigens. LPG showed the greatest difference for optic nerve antigens. Immunological effects in POAG and LPG, first described by Dr M.B. Wax (who discussed the presentation), were confirmed. The implications of these observations for the pathophysiology and diagnosis of glaucoma require further study.

Evaluation of the utilization of glaucoma surgery before and after the introduction of newer, more potent anti-glaucoma medications

Medicare data (ICD-9 diagnosis and CPT procedure codes) were used to develop US estimates for the years 1994-1999. This interval was selected to surround 1996, when newer and more effective pressure-lowering medications (e.g., prostaglandin agents, topical carbonic anhydrase inhibitors, and selective alpha-1 agonists) were introduced into clinical practice. Study results comparing the years 1996-1999 showed significant decreases in the number of inpatient (4000 versus 1140) and outpatient (143,440 versus 83,540) glaucoma procedures, while the prevalence of glaucoma remained consistent. This Medicare-based study confirms the personal experience of glaucoma specialists in the USA that the pressure-lowering efficacy and patient acceptance of the expanding list of anti-glaucoma medications has reduced the frequency of (need for) glaucoma surgical procedures.

Three glaucoma symposia deserve to be acknowledged.

1. Traumatic glaucoma: mechanisms and management: combined meeting with the American Society of Ocular Trauma

Drs G. Phillip Mathews and Frenc P. Kuhn arranged an outstanding program on the mechanisms and management of traumatic glaucoma. The presentations by glaucoma specialists were excellent, as follows: Drs J.T. Whitson (epidemiology and terminology), A.D. Beck (intraocular hemorrhage), P.A. Netland (damage to trabecular meshwork), H. Barnebey (angle recession), M.R. Moster (lens-induced), C.A. Girkin (inflammation), J.R. Samples (ingrowth), R.C. Allen (foreign bodies), R.J. Noecker (chemical), A.L. Coleman (radiation, electrical, and thermal), and J. C. Tsai (carotid and cavernous fistulas).

2. Glaucoma Management 2002: Medical and Surgical State of the Art combined meeting with Prevent Blindness America Inc.

Dr Wallace L. M. Alward organized a superb symposium featuring presentations by Drs P.R. Lichter, D.E. Gaasterland, K.M. Joos, J.S. Schuman, G.L. Skuta, N.A. Zabrisikie, and M. Lloyd. Dr Gaasterland presented ten-year data from the Advanced Glaucoma Intervention Study (AGIS). Independent of treatment (laser trabeculoplasty or trabeculectomy) sequence, 60-70% of eyes with advanced glaucoma did well, with stable visual fields and visual acuity from baseline. While eyes with lower intraocular pressure did better, progression of field loss was not completely accounted for by pressure level alone. The symposium ended with Dr Paul L. Kaufman presenting the Robert N. Shaffer Lecture on the Medical Therapy of Glaucoma: where are we going, and when will we get there?

3. Surgical decisions at the combined open-angle glaucoma and Pan-American Glaucoma Society meeting

Dr Paul L. Lichter prepared an excellent symposium addressing when to perform filtering surgery (Dr E.J. Maul), which filtering procedure to perform and how to perform it (Dr R. Cohen), indications and approach to combined procedures (Dr S.D. Orengo-Nania), managing the failing bleb (Dr C. Harleben), leakage, overfiltration, and maculopathy: prevention and management of hypotony (Dr S.F. Lerner), and when to use tubes and which ones to use (Dr G.L. Skuta).

I highly recommend purchasing the CD-ROM of these three outstanding symposia, as a digital reference.