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NEW ORLEANS -- The scientific program at the American Academy of Ophthalmology meeting included two poster sessions. Several of the studies included in the sessions are summarized below.

Cataract Surgery Helps Prevent Falls

A longitudinal cohort study from Australia included data on 196 patients whose fall history was compared before and after first-eye cataract surgery. Study participants were 65 or older and had bilateral cataracts. Follow-up continued for 2 years after initial surgery.

Overall, fall incidence declined by 33% following first-eye surgery (incident rate ratio 0.67, 95% CI 0.49-0.92), after adjustment for age, sex, comorbidities, physical functioning, and medication use. An adjusted analysis showed that reduced visual acuity in the dominant eye more than doubled the risk of falls (IRR 2.20, 95% CI 1.02-4.74). A spherical equivalent change in the operated-eye spectacle lens ≥0.75 D also doubled the risk of falls (IRR 2.17, 95% CI 1.23-3.85).

Cataract surgery was associated with significant improvement in binocular habitual visual acuity, habitual visual acuity of the operated eye, binocular contrast sensitivity, and contrast sensitivity of the operated eye (P<0.001 for all comparisons). The proportion of patients who did not use glasses increased from 47.8% to 63.3% (P<0.001) and the proportion requiring multifocal lenses decreased from 43.4% to 28.6% (P<0.001).

The investigators concluded that first-eye cataract surgery significantly reduced incident falls. They cautioned that major changes in the dioptric power of spectacle correction of the operated eye after surgery increased the risk of falls. Careful postoperative refractive management is necessary to maximize the benefits of cataract surgery.

Laser Treatment Effective for Floaters

A retrospective analysis of 1,272 YAG laser vitreolysis procedures to treat symptomatic "floaters" showed substantial resolution of the protein flecks and a complication rate of less than 1%.

Performed in 680 patients, the procedures were associated with a total of 10 complications. The complications consisted of transient spikes in intraocular pressure (IOP) in seven cases, two cases of phakic lens hit, and one retinal hemorrhage. The IOP spikes responded to treatment with topical antihypertensive medications.One patient required cataract surgery after a phakic lens hit and the other patient remains under observation. The retinal hemorrhage resolved without incident after 3 months.

Most patients reported reductions or resolution of floaters, and no patient had worsening of floaters after laser procedures, during follow-up for at least 1 year and for as long as 4 years, reported Inder Paul Singh, MD, of Eye Centers of Racine and Kenosha in Wisconsin. Four patients with existing uveitis had no worsening after laser treatment, 27 patients with diabetic retinopathy had no postprocedure evidence of macular edema, and two of four patients with vitreomacular tension syndrome had resolution of the condition immediately after laser procedures.

Exercise May Protect Against Glaucoma

The risk of glaucoma decreased as exercise intensity increased, according to data from adult participants in the 2005-2006 National Health and Nutrition Examination Survey.

The analysis involved 70,246,160 participants, including 2,174,821 (3.1%) with glaucoma. The data showed that individuals without glaucoma had significantly significantly more moderate or vigorous physical activity each day (13.8 minutes) than did the participants with glaucoma (9.2 minutes, P=0.02). The glaucoma subgroup also had significantly lower exercise intensity by pedometer measurements (242.6 vs 321.2 intensity units/minute, P=0.0003).

The findings are consistent with those of previous studies, suggesting an association between exercise and decreased glaucoma risk, Victoria L. Tseng, MD, of the University of California Los Angeles, and co-investigators reported. Though not evaluated in the study, potential mechanistic explanations for the association include a direct effect of physical activity on intraocular pressure and an exercise-induced increase in blood flow to the optic nerve.