Intraocular Pressure and Ocular Biometrics Changes After Phacoemulsification in Glaucomatous Patients and Age Matched Controls, Comparative Study
Phase: NA
Conditions: Glaucoma, Cataract
Sponsor: Mai Nasser Abd Elmohsen

 
Intraocular pressure and ocular biometrics changes after phacoemulsification in 
glaucomatous patients and age matched controls, comparative study 
 
September 14th, 2019 
 
 
 
 
Full Protocol 
 
 
 
 
 
 
 

Background and introduction 
Phacoemulsification is one of the most commonly performed surgeries in ophthalmic 
practice. One of the main topics of interest regarding phacoemulsification is its effect on 
intraocular pressure (IOP) readings whether in glaucomatous or non-glaucomatous 
eyes by comparing the IOP changes before and after surgery. 1,2  
The effect of phacoemulsification on ocular biometrics as the depth of the anterior 
chamber (ACD) has been previously studied 3. It showed significant results especially in 
cases of thick lenses or preoperatively shallow anterior chamber (AC) or narrow AC 
recess as in cases of angle closure glaucoma 2. 
 
 
Changes in the AC angle configuration and the angle opening distance at 500 microns 
(AOD 500) before and after phacoemulsification have also been studied 3.AOD 500  is 
defined by UBM as the distance of a perpendicular from the trabecular meshwork on the 
iris at a point 500 μm from the sclera spur4. In primary angle closure glaucoma patients 
even a clear lens extraction showed a significant increase in AOD 500 after 
phacoemulsification5.However, there is no clear evidence whether preoperative ocular 
biometrics could predict the amount of this IOP reduction after phacoemulsification and 
whether further filtering surgeries or medications will be still needed for IOP control. 
Some studies have shown a significant decrease in IOP after phacoemulsification6, with 
the effect being more significant and the rate of decrease higher the narrower the 
angle7.However, other studies stated that there's a rise of IOP after cataract removal 8 in 
the first week and it subsides later on. Another study actually proposed there's no 

correlation between phacoemulsification and the IOP pre and postoperatively.9Some 
studies that stated that there's lowering of IOP after phacoemulsification also showed 
that filtering surgery was eventually needed in the vast majority of glaucomatous cases 
and in few of them only cataract removal was sufficient. 10  
This study aims to evaluate the changes in IOP and anterior segment parameters 
represented by the central ACD and the AOD 500 measured by UBM before and after 
phacoemulsification. 
In our study we aim to establish a qualitative as well as quantitative relationship 
between phacoemulsification and the IOP. Also we aim at studying this relationship in 
non-glaucomatous eyes, open-angle and closed-angle glaucomatous eyes(only 
appositional type, not synechial angle closure).We want to correlate these changes to 
the changes in ACD and AOD at 500 pre and postoperatively to establish a quadruple 
relationship between phacoemulsification on one hand, and the percentage of IOP 
change ,ACD change and AOD at 500 change on the other hand to study the effect in 
various eyes and a wide spectrum of the population to earn more accurate results than 
previous studies. 
Patients and methods 
An estimation of sample size was performed considering a confidence level of at least 
80% with an alpha error of 0.05. On the basis of this estimation, a total of 46 patients 
was considered adequate. We will include 60 patients taking into account the possibility 
of drop-outs in the postoperative follow up period.  

This is an observational, comparative, cross sectional study that will be conducted at 
Kasr Alainy Cairo University Hospitals. Data collection will adhere to the tenets of the 
Declaration of Helsinki. Written informed consent will be obtained from all participants. 
Patients will be recruited from the glaucoma subspecialty and general outpatient clinics 
if they fulfill the following criteria; Age 40-70 years, visually significant cataracts with 
best-corrected visual acuity (BCVA) equal to or worse than 6/12, patients candidates for 
standard cataract surgeries without adjunctive procedure (e.g., pupil stretching or iris 
hooks). Exclusion criteria include (1) Major intraoperative orpostoperative complications 
from cataract surgery; (2) Peripheral anterior synechiae (PAS) detected by indentation 
gonioscopy; (3) Uveitis, severe retinal diseases, or congenital Anomalies, (4) History of 
ocular trauma or any intraocular Surgery 
In addition to the routine full ophthalmological examination (Visual Acuity, Auto-
refractometer, Slit lamp and fundus examination). All patients meeting the inclusion 
criteria will have the angle of the anterior chamber assessed by indentation gonioscopy 
preoperatively to detect whether the angle is opened or closed and to exclude the 
presence of peripheral anterior synechiae. Also intraocular pressure will be measured 
using a calibrated Goldman Applanation Tonometry postoperatively. Anterior Chamber 
Depth & lens thickness will be measured by Optical Biometry (lenstar 900) as well as 
measurement of the angle & lens vault using the Ultrasound Biomicrosopy (UBM) 
before and 1 month after cataract surgery. IOP will be measured pre- & postoperatively 
on day 7 and 30. 
 

Statistical analysis plan: 
All data will be entered into Excel spreadsheets (Microsoft Corporation, Redmond, WA, 
USA). All statistical analyses will be performed using IBM SPSS version 22.0 software 
(IBM Corp., Armonk, NY, USA). Descriptive statistics will be summarized as the mean ± 
standard deviation for numerical data, frequencies and percentages for categorical data. 
The ANOVA -test and Pearson moment correlation will be used to compare the means 
for the numerical data and to identify correlations between them. Chi-square test will be 
used to compare categorical data. P-values ≤ 0.05 will be considered statistically 
significant. 
References 
1) MelanciaD,Abegao-Pinto L,Marquez-Nevez C:Cataract Surgery and intraocular 
pressure;J Ophthalmic Research 2015;53:141–148 
2) Hsu C-H, Kakigi CL, Lin S-C,Wang Y-H, Porco T, Lin SC. Lens position 
parameters as predictors ofintraocular pressure reduction aftercataract surgery 
in nonglaucomatouspatients with open angles. Invest Ophthalmol Vis Sci. 2015; 
56:7807–7813. 
3) Ufuk Elgin, EmineSen,TulaySimsek, Kemal Tekin and PelinYilmazbas: Early 
postoperative effects of cataract surgery on anterior segment parameters in 
open-angle glaucoma and pseudoexfoliationglaucoma;Turk J Ophthalmol. 2016 
Jun;46(3)95-98. 
4) Martha Kim , Ki Ho Park, Tae-Woo Kim, Dong MyungKim:Changes in Anterior 
Chamber Configuration after Cataract Surgery as Measured by Anterior 
Segment Optical Coherence Tomography;Korean J Ophthalmol 2011;25(2):77-
83. 

5) Man, X., Chan, N.C.Y., Baig, N. et al: Anatomical effects of clear lens extraction 
by phacoemulsification versus trabeculectomy on anterior chamber drainage 
angle in primary angle-closure glaucoma (PACG) patients;Graefes Arch 
ClinExpOphthalmol (2015) 253: 773.  
6) S AIssa, J Pacheco, U Mahmood, J Nolan, S Beatty. A novel index for predicting 
intraocular pressure reductionfollowing cataract surgery. Br J Ophthalmol 
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7) Lin SC,MasisM,PorcoTC,PasqualeLR.Predictors Of Intraocular Pressure After 
Phacoemulsification In Primary Open-Angle Glaucoma Eyes With Wide Versus 
Narrower Angles (An American Ophthalmological Society Thesis). Trans Am 
OphthalmolSoc 2017;115:T6 [1-13]. 
8) Coban-Karatas M, Sizmaz S, Altan-YayciogluR,Canan H, Akova YA. Risk 
factors for intraocular pressure rise following phacoemulsification. Indian J 
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9) Gabriella Johansson.Effect of Phacoemulsification on intraocular 
pressure.Degree project work in optometry.Level: First Level.Nr: 2011: O30. 
10) Ianco R, CorbuC.Intraocular pressure after phacoemulsification in patients 
withuncontrolled primary open angle glaucoma.Journal of Medicine and Life Vol. 
7, Issue 1, January-March 2014, pp.11-16