الفهرس 
1. IntroductionOnly 14 pages are availabe for public view
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Abstract
Cataract surgery with phacoemulsification continues to be one of the most popular surgical procedures in ophthalmologic practice.
Unlike other maneuvers, ultrasonic energy and fluidics produce mechanical effects that cause an inflammatory reaction compression, and hypoxia on the tissue. Phaco surgeons can measure the ultrasonic energy that was emitted through estimation of the phaco time ,so surgeons can control the usage of ultrasound energy through controlling the phaco time.
The inflammatory reaction causes release of inflammatory mediators diffuse through the vitreous and disrupt the blood retinal barrier to cause pooling of serum in retina resulting in macular edema.
With an incidence of 0.1–9 %, macular edema is one of the most important complications of cataract surgery. It is the main cause of postoperative visual impairment
On examination the RNFL thickness by OCT the media opacity caused by cataracts will increase light scattering and absorption, so the RNFL thickness measurement can be increased after uncomplicated cataract surgery.
Aim of the study: The aim of this work is to determine the changes in prepapillary retinal nerve fiber layer and macular thickness changes after phacoemulsification using OCT.
Subjects and Methods: The present study is highly selective study included 50 eyes of 50 patients who underwent uncomplicated phacoemulsification between May 2016 and March 2017 at the ophthalmology department at the Menoufia university hospital.
Optical Coherence Tomography Measurements: the OCT measurements (spectralis spectral domain optical coherence tomography(Heidelberg engineering) were performed one day before phacoemulsification, one week then one month postoperatively.
Macula examination: The patients were asked to fix on an internal target and the operator has centered the macular scans on the foveal pit, we selected the retinal map analysis protocol on the OCT to reconstruct a surface map as a false-color topographic image displayed with numeric averages of the measurements.
Retinal nerve fiber examination: the spectralis OCT software calculates the RNFL thickness for the average thickness (overall global thickness).
The results of the current study can be summarized as follow: This study including 50 eyes of 50 subjects from which age range between (40-70) years old and males (52%) were more than females (48%).
The retinal nerve fiber thickness average were 96.52 μm (SD± 12.00), 101.28 μm (SD ± 11.87), 111.96 μm (SD ± 11.43), one day before cataract surgery, after 1st week of surgery, and one month later respectively .We found that the central retinal nerve fiber thickness measurements after one week and one month of the operation were significantly higher than those measured preoperatively (P <0.001).
The average central macular thickness were 230.58 μm (SD± 25.46), 259.22 μm (SD ± 25.44), 271.12 μm (SD ± 24.61) one day before phaco, after one week of surgery, and one month later respectively. We found a statistically significant increase in the central macular thickness in the 1st week and the 1st month after surgery than before it (P <0.001).This increase in the macular thickness was significant in all 9 areas of macula(P <0.001). The increase of macular thickness is positively correlated to the phaco time after 1st week (P <0.001) and 1st month of phaco (P =0.001).