Abstract
Purpose:
To evaluate the effect of clear lens extraction on intraocular pressure (IOP) and anterior chamber angle parameters in patients with Primary Angle Closure (PAC) who have persistently raised IOP following laser peripheral iridotomy (LPI)
Methods:
Thirty four eyes of 34 phakic patients with PAC, Best Corrected Visual Acuity ( BCVA) of 20/20 or better and IOP >25 mm Hg persisting till at least 8 weeks post LPI were included. Work up included Applanation tonometry, Biometry with Lens Thickness (LT) and Anterior Segment Optical Coherence Tomography (AS-OCT) which evaluated several anterior chamber angle parameters including Angle Opening Distance at 500µ from scleral spur (AOD 500) and the Trabecular Iris Angle (TIA)). All eyes underwent clear corneal phacoemulsification with a foldable single piece hydrophobic acrylic IOL implantation in the capsular bag. Follow up was done at 3, 6 and 12 months. IOP < 18 mmHg without ocular hypotensive medications at 1 year follow up was criteria for absolute success.
Results:
There were 20 females and 14 males with mean age 57.2 +/- 4.2 years. The preoperative IOP of 27.1+/-1.55 mmHg reduced to 11.2 +/-1.2mmHg at 12 months (p<0.0001). Significant widening of the anterior chamber angle was noted at 1 year with an increase as compared to baseline values in AOD500 at 0 degrees (0.104+/-0.015mm vs 0.31+/-0.013mm) ; AOD500 at 180 degrees (0.202+/-0.008mm vs 0.412+/-0.012mm) ; TIA at 0 degrees (9.3+/-3.2 degrees vs 32.7+/-5.6 degrees) ; TIA at 180 degrees (9.12+/-3.2 degrees vs 31.7+/-5.6 degrees) ;(All p<0.0001). Pre op LT showed significant positive correlation with reduction in IOP (r = 0.666, p<0.0001). Eyes with LT >/=4.9 mm had significantly higher reduction in IOP; p<0.0001. Pre-operatively all eyes were on ocular hypotensive medications with 27 eyes requiring 2 medications, 4 eyes requiring 3 medications and 3 eyes being on monotherapy. Post operatively, absolute success was achieved in 32 eyes (94.1%), while 2 eyes were on 1 topical medication. None of the eyes had a drop in BCVA at final follow up.
Conclusions:
In eyes with PAC and persistently raised IOP post LPI, a clear lens extraction is associated with a significant reduction in IOP and widening of the anterior chamber angle parameters. An early lens extraction appears to be curative in these cases with the majority of patients achieving control of IOP off medications and may be adopted as the standard of care.
Keywords: 568 intraocular pressure •
420 anterior chamber •
743 treatment outcomes of cataract surgery