Abstract
Purpose: :
To determine whether pre-operative ocular axial length was associated with an expected reduction in intraocular pressure (IOP) following cataract surgery in glaucomatous eyes. A secondary aim was to assess the effect of cataract extraction on IOP in glaucomatous eyes after two years follow-up.
Methods: :
The study was retrospective and included one eye of 201 consecutive patients managed within a specialist glaucoma service, who had undergone cataract surgery. Only patients diagnosed with manifest glaucoma or suspicion of glaucoma were included. Axial length (mm) was determined using the Zeiss IOL Master®. Pre-operative IOP (mean of 3 IOP measurements within 3 months prior to surgery) was compared with IOP values measured at 6 and 24 months post-operatively. The mean number of topical anti-glaucoma medications administered at the time of IOP measurement was documented. Paired t-tests were used to compare IOPs and medication use (p≤0.01 being considered statistically significant). A Pearson’s coefficient of correlation (r) was determined to assess for any association between axial length and IOP reduction.
Results: :
Mean IOP pre-operatively was 17.5±3.9mmHg with use of a mean number of 0.91 topical anti-glaucoma medications/eye. Mean IOP was significantly reduced at 6 months post-operatively by 14.7% to 14.6±3.1mmHg (p<0.001), with a reduction of mean topical medication use to 0.72 (p<0.001). At 24 months (IOP=14.9±3.4mmHg) no further significant change in IOP reduction, compared with 6 month values, was identified, but the mean number of anti-glaucoma medications had significantly increased from 0.72 to 0.98 (p<0.001), an amount that was not statistically significantly greater than the pre-operative value of 0.91. No correlation was found between axial length and post-operative IOP change (r = -0.05;NS).
Conclusions: :
Ocular axial length was not identified as a factor associated with IOP reduction following cataract surgery in glaucomatous eyes. The post-operative IOP reduction seen at 6 months was sustained at 2 years post-operatively, but the latter required the same level of medication use as had been used pre-operatively.
Keywords: intraocular pressure • cataract • clinical (human) or epidemiologic studies: outcomes/complications