الفهرس 
Anatomy of The LensOnly 14 pages are availabe for public view
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Abstract
Cataract and glaucoma are the first and second leading causes of blindness
worldwide that affect the older population. Hence, the interaction between these two
diseases is of interest to clinicians.
Phacoemulsification cataract surgery has been shown by numerous studies to
significantly reduce intraocular pressure (IOP), in glaucomatous and nonglaucomatous
eyes.
Long term studies have shown a DROP in IOP of about 4 mm hg in primary open
angle glaucoma patients and non-glaucomatous patient. Although the physiological
reason for decrease IOP after cataract surgery remain not fully understood but the
facility of outflow is known to increase after cataract surgery. Cataract surgery is a very common and highly refined surgery with a favourable
risk/benefit profile including improved visual acuity and visual field. The
widespread general belief that cataract extraction alone lowers IOP 2-4 mmHg is
slowly evolving towards an understanding of a larger and more sustained IOP
reduction, especially in patients with higher preoperative IOP.
As the lens grows the anterior lens capsule is displaced forward causing the
zonule to place anteriorly directed traction on the ciliary body and uveal tract
which in turn compress the canal of schlemm and trabecular meshwork. As the
ciliary body is displaced forward by the enlarging lens, the tendon relaxes and the
space between trabecular plates becomes narrowed.
Phacoemulsification with foldable IOL implantation can significantly deepen
the ACD, widen the anterior chamber drainage angle and lower IOP. The amount of IOP reduction was approximately 2.86 mmHg and the postoperative reduction
in IOP was proportional to the increase in angle width.
This study carried out on 48 eyes of patients who underwent
phacoemulsification and IOL implantation surgery.
There were 12 male and 16 female. Their age was ranging from 47 years to 72
years with an average of 59.96 ± 7.173 years. The mean of their pre best corrected
visual acuity was 0.492 ± 0.1820.
The visual acuity changes after cataract removal by phacoemulsification to
0.825 ± 0.1670 post-operative.
The preoperative intraocular pressure was 16.67 mm Hg ± 3.587 mm Hg and the
postoperative intraocular pressure was 13.81 ± 3.126 mm Hg The preoperative ACD was 3.1381 ± 0.49475 and the postoperative was 3.3612
± 0.47661.
The preoperative iridocorneal angel width was 25.83 ± 2.529 and the
postoperative was 32.06 ± 3.423.
So, there is significant improvement in visual acuity post uncomplicated
phacoemulsification, significant decrease in the intraocular pressure measured post
phacoemulsification and significant increase in ACD depth, and iridocorneal angel
width.
A lot of studies have been done to assess IOP after cataract surgery. Wide
variation in mean IOP reductions (1.1-13.5 mm Hg) has been reported in such
studies. So, cataract surgery to lower IOP may be beneficial especially in developing
countries or where the close follow up necessary by traditional glaucoma surgery is
difficult. So it appears safe to lower IOP in patient with mild to moderate
glaucoma with avoiding morbidity of traditional glaucoma surgery.
In conclusion cataract surgery without complication can widen the anterior
chamber and lower the intraocular pressure and can improve the visual acuity with
short period of follow up not like the traditional glaucoma surgery which need long
follow up and special care more than phacoemulsification.