Abstract
Purpose: :
To determine the effect of phacoemulsification on intraocular pressure (IOP) in eyes with anatomically narrow angles that have had a previous laser peripheral iridotomy (LPI). We also would like to determine whether there are certain preoperative factors (such as axial length, refractive error and anterior chamber depth) that may predict a subsequent decrease in IOP following cataract surgery in this population.
Methods: :
We conducted a retrospective analysis of eyes that underwent a LPI for narrow angles with subsequent phacoemulsification cataract extraction at the Duke Eye Center and Winston offices between January, 1998 and December, 2006. Over 300 charts were reviewed. Individuals with ocular surgeries and/or glaucoma lasers occurring between the time of LPI and phacoemulsification were excluded. Differences between IOP, medications, and visual acuity were compared using paired t-tests. The significance of the relationship between preoperative factors (axial length, refraction, anterior chamber depth) and the post-operative IOP reduction is being assessed using linear regression.
Results: :
We have performed preliminary statistical analysis on our data collected at this point and currently sixty-five (65) eyes with anatomic narrow angle have met appropriate inclusion criteria. For this subset, mean IOP prior to LPI was 21.5 ± 8.1 mm Hg. Following LPI, mean IOP was 18.1 ± 5.2 mm Hg and mean reduction in IOP was 3.4 ± 8.7 mm Hg (P=.003). At a mean follow-up of 10.4 ± 4.9 months following phacoemulsification, mean IOP was 15.2 ± 2.9 mm Hg yielding an average IOP reduction of 3 ± 5.5 mm Hg (P = <0.001). The mean number of IOP lowering medications prior to cataract surgery was 1.1 ± 1.1 and was 0.6 ± 1 following surgery. Mean reduction in medications was 0.4 ± 0.8 (P<0.001). Mean visual acuities before and after PCIOL were 20/70 and 20/40 respectively. Fifty-six (56) eyes (n=62) experienced improvement in vision or remained the same. Over 50% of eyes had final visual acuity of 20/25 or better. Linear regression is in progress to determine the correlation between preoperative factors (axial length, refraction, anterior chamber depth) and the post-operative IOP.
Conclusions: :
At this point in our analysis it appears that phacoemulsification with IOL resulted in improved visual acuity, reduced IOP and decreased dependence on IOP medications in eyes that underwent prior LPI for anatomically narrow angles. Further analysis regarding the remainder of our data is pending, as is investigation to determine the correlation between preoperative factors (axial length, refraction, anterior chamber depth) and the post-operative IOP.
Keywords: intraocular pressure • cataract