الفهرس 
Chapter (I): AstigmatismOnly 14 pages are availabe for public view
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Abstract
Intraocular lens implantation is the established mode of visual
rehabilitation following cataract extraction. The goal of current refractive
cataract surgery is an excellent uncorrected visual acuity in all fixation ranges,
which requires a zero postoperative refractive astigmatism. This goal may be
reached by implantation of toric lenses and by a variety of corneal procedures.
The prevalence of astigmatism increases with age and it is estimated that
approximately 50% of the population older than 60 years has astigmatism of
more than 1.00 Diopter (D). Up to 22% of patients undergoing cataract surgery
have a preexisting astigmatism exceeding 1.50 D.
In patients with astigmatism, where the refractive power of the eye is most
in one direction and least 90 degrees away, a standard monofocal IOL is unable
to correct both powers. In such situations, the residual astigmatism causes
reduced uncorrected visual acuity. Astigmatism may be corrected
postoperatively with the use of spectacles or contact lenses. Alternatively,
incisional techniques may be used at the time of cataract surgery to induce
changes in the curvature of the cornea in an attempt to reduce corneal
astigmatism. So, the aim of this study was to evaluate the contribution of
intraocular lens to the overall astigmatism following phacoemulsification.
To elucidate our aim, this study was cross sectional case series conducted
on 30 patients with overall astigmatism to evaluate the contribution of
intraocular lens to the overall astigmatism following phacoemulsification; they
attended to the ophthalmology outpatient clinic of Menoufia University during a
period time from April 2022 to February 2023.
Study procedure and surgical method: All study patients were carefully
examined post operatively at least 3 months postoperative. Ophthalmic
examination included manifest refraction and keratometry.
The results of this study could be summarized as follow:
Age<60 was (10.3%), age≥60 was (89.7%) and the total mean was
(64.28±6.61). Also, male was (41%) and female was (59%) of sex.
The mean sphere was (-0.23±4.05) and cylinder was (-1.56±0.54) .
The mean axial length was (23.57±1.12) and was ranged from 22.6 to 26.6.
Additionally, the mean anterior chamber depth was (2.77±0.28) and was
ranged from 2.5 to 3.5.
The mean K1 was (41.84±2.01)), K2 was (43.12±1.68), and mean K was
(42.49±1.72).
The mean corneal astigmatism was (-1.37±1.31) and was ranged from -4.8
to 1.9.
The mean sphere was (-0.74±1.40), cylinder (manifest astigmatism) was (-
1.49±1.03) and axis was (93.41±29.61).
Mean change of corneal astigmatism compared to manifest astigmatism was
(-0.13±0.93). However, there was no significant difference between corneal
astigmatism and manifest astigmatism (t=0.842, P=0.405).