ORIGINAL ARTICLE

Brimonidine 0.2% for Prevention of

Intraocular Pressure Elevations after YAG

Posterior Capsulotomy

Muhammad Khizar Niazi¹, Ali Rauf², Yasser Nadeem³

^1-3Combined Military Hospital (CMH) and Medical College, Lahore

ABSTRACT

Purpose: To see the efficacy of Brimonidine 0.2% in controlling intraocular pressure (IOP) elevations after YAG-

posterior capsulotomy.

Study Design: Quasi Experimental study.

Place and Duration of Study: Combined Military Hospital, Lahore from February to December 2019.

Material and Methods: Eighty-four pseudophakic eyes with Posterior capsular opacities were included in the

study. Exclusion criteria were; patients with diagnosis of glaucoma, complications during surgery or in

postoperative period. Cases with any other ocular disease or history of ophthalmic surgeries prior to Nd: YAG

laser posterior capsulotomy were also excluded from the study. Before the laser treatment, Intraocular Pressure

was measured in all patients. After YAG capsulotomy patients were either administered Brimonidine 0.2% or were

not given any IOP lowering drug after noting a rise in Intra-ocular pressure. Eyes received either one drop of

Brimonidine 0.2% per day starting one hour after the laser procedure or no treatment after laser therapy.

Intraocular pressure was measured one hour and three days after laser therapy in both the groups.

Result: Mean IOP of 84 eyes was 14.43 mm of Hg before the procedure.. One hour after the procedure, 52

patients had a rise in IOP. Mean IOP-hike was 8.76 mm of Hg. 26 patients were administered Brimonidine drops

immediately while rest were left untreated and observed. On the third day after laser therapy, only one patient had

an increased IOP in the treated group while 18 patients in the un-treated group had higher than normal IOP. After

3^rdday, all patients were treated for the raised IOP.

Conclusion: Once daily dose of Brimonidine 0.2% is effective in maintaining a lower IOP after YAG

capsulotomy.

Key Words: Brimonidine, Intraocular pressure, Nd YAG capsulotomy.

How to Cite this Article: Niazi MK, Rauf A, Nadeem Y. Brimonidine 0.2% for Prevention of Intraocular Pressure

Elevations after YAG Posterior Capsulotomy. Pak J Ophthalmol. 2020, 36 (2): 147-150.

Doi: 10.36351/pjo.v36i2.1006

INTRODUCTION

commonest post-operative complication of the modern

surgery¹. Reduced visual acuity that is induced by

Cataract surgery is continuously being improved upon

and associated complications declining day by day.

PCO is reported in 20% to 40% of patients, 2 to 5

years after cataract surgery². At present, the only

Posterior capsular opacification (PCO) is the

definite solution of PCO is Nd: YAG laser

capsulotomy. It involves clearing the visual axis by

making a central clear area within the opaque posterior

capsule. Although this procedure is facile and time-

saving, there are recognised complications, including

Correspondence to: Muhammad Khizar Niazi

CMH Lahore and Medical College, Lahore

E-mail: Khizaraleem@hotmail.com

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Pakistan Journal of Ophthalmology, 2020, Vol. 36 (2): 147-150

Brimonidine 0.2% for Prevention of Intraocular Pressure Elevations after YAG Posterior Capsulotomy

retinal detachment, damage to the IOL, cystoid

these mechanisms are mediated by stimulation of

ocular a2-adrenoceptors. Brimonidine may also have a

neuroprotective effect in addition to its ability to lower

IOP. The mechanisms underlying this are not

completely comprehended but may include an up

regulation of basic fibroblast growth factor, causing a

cell hyperpolarization and a reduction in the release of

glutamate from neurons, or an up regulation of

antiapoptotic genes⁹. An early study concluded that

brimonidine in concentrations of 0.08, 0.2 and 0.5%

with double daily dosing lowered IOP by 20 – 30% in

glaucoma and ocular hypertension patients¹⁰.

macular oedema, an increase in intraocular pressure,

iris haemorrhage, corneal oedema, IOL subluxation,

and exacerbation of localized endophthalmitis³.

There are several reports that have mentioned

displacement of IOLs after laser treatment. By

employing dual-beam partial coherence interferometry

the procedure has been shown to produce a negligible

but measurable backward displacement of the IOL. It

is quoted that the larger capsulotomy size induces

greater backward movement, and it is recommended

that small openings should be carved to avoid this

complication⁴. It is also recommended in case of large

capsulotomies to prescribe new spectacles at least 1 to

4 weeks after Nd: YAG laser capsulotomy⁵. The

commonest complication of posterior capsulotomy is

raised IOP. Various explanations which have been

given for the pressure rise following Nd: YAG laser

treatment include the collection of debris in the

MATERIAL AND METHODS

This study was performed at Eye department, CMH

Lahore from February 2019 to December 2019.

Written informed consent was obtained from the

patients before intervention. Ethical committee board

of Combined Military Hospital, Lahore approved the

study. A total of 84 pseudophakic eyes with posterior

capsular opacity and BCVA of ≤ 6/9 (Log MAR

0.176) were included in the study. Only those cases

trabecular

meshwork,

pupillary

block,

and

inflammatory oedema of the ciliary body or iris root

co-existent with angle closure. Despite the

prophylactic treatment, increased IOP was reported in

15% to 30% of patients in many studies⁶. Other

mechanism includes trabeculitis as a result of radiating

“shock waves”⁷.

that

had

undergone

with

uncomplicated

posterior chamber

phacoemulsification

intraocular lens (PCIOL) in the bag implantation at

CMH, Lahore were included in the study. Multiple

surgeons did the surgeries. Exclusion criteria were;

complications during cataract surgery or during the

postoperative period. Diagnosed cases of glaucoma,

patients with corneal opacities, retinal diseases,

uveitis, optic neuropathy, and those who had

undergone any other ophthalmic surgeries prior to Nd:

YAG laser posterior capsulotomy treatments were also

excluded from the study.

The aetiology of CME following Nd: YAG laser

capsulotomy most likely encompasses movement of

the vitreous cavity and vitreous damage, which results

in the release of inflammatory mediators. Vitreoretinal

traction as a result of the procedure may also play a

part. Previous studies have gone into details to probe

variations of macular thickness after Nd: YAG laser

capsulotomy. Although a few studies did report

cystoid macular oedema, majority of them found no

significant changes in macular thickness following Nd:

YAG laser capsulotomy⁷.

All the patients who underwent Nd: YAG laser

were examined preoperatively, at 1hr. postoperatively,

and at 3^rdday after Nd: YAG laser capsulotomy.

Patients were divided into two groups according to the

treatment. Group 1 received Brimonidine while Group

2 was observed without treatment from time of laser

till 3^rdday. There were 42 patients in each group.

Multiple surgeons performed the capsulotomy, though

each capsulotomy was performed by a single surgeon

in a single session with an Nd: YAG laser. All patients

underwent a complete ocular examination on all visits,

including BCVA, refraction (auto refraction followed

by subjective refraction); slit lamp biomicroscopy, IOP

measurement. BCVA was measured in a darkened

room using projection-type Snellen chart. Tropicamide

0.1% was administered for pupillary dilatation prior to

Brimonidine exerts its effects in the eye due to its

significant a2- adrenoceptor affinity, due to which it is

considered a standard reference compound. In radio

ligand binding assays using human colonic cell lines

(a2-adrenoceptors) and human cerebral cortex neurons

(a1-adrenoceptors), the ratio of a2:a1-adrenoceptor

selectivity was 974 for brimonidine, 151 for clonidine

and 30 for apraclonidine, thus, indicating that

brimonidine was 6 – 32 times more selective for a2-

adrenoceptors than clonidine and apraclonidine,

respectively⁸. Brimonidine lowers IOP by both

decreasing aqueous humor production and enhancing

aqueous outflow via the uveoscleral pathway. Both of

Pakistan Journal of Ophthalmology, 2020, Vol. 36 (2): 147-150

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Muhammad Khizar Niazi, et al

the procedure. All pretreatment data and data at 3^rdday

follow-up were collected from non-dilated eyes.

However, data at 1 hr. after treatment were taken from

dilated eyes. After capsulotomy, a combination of

antibiotic and steroid (Tobradex, Alcon laboratories)

was prescribed four times daily for 7 days. SPSS 17

Statistics was used for statistical analysis. The

independent t-test was used for the comparisons

between the groups. A P-value of < 0.05 was

considered statistically significant.

control was effectively achieved with 1 week of

brimonidine use after prophylactic apraclonidine¹⁴. In

a recent study, it was shown that IOP rose after YAG

capsulotomy but it did not require use of any anti-

glaucoma therapy¹⁵. Holweger and Marefat reported

no significant rise in IOP at 1–3 hrs and 1 day after

capsulotomy¹⁶. Some researchers showed no

significant change in IOP after Nd: YAG capsulotomy.

There are also some studies which indicate that

rise in IOP was associated with the level of energy

used^17-19

Other researchers have denied such

relationship^20,21

RESULTS

The limitation of our study was that the number of

shots applied during laser procedure, total power used,

and the level of post-procedure inflammation

suppressed with an agent can be significant agents

affecting IOP variations after YAG laser. Additional

studies are required to evaluate the effects of these

factors on IOP modulations after YAG laser posterior

capsulotomy. Another limitation of this study was

short follow-up.

Sixty-two males and 22 female patients were enrolled

in this study. 81 patients received treatment in

unilateral eyes and 3 patients in both eyes. There were

42 eyes in each group. Mean age of the patients was

65.30 ± 10.10 years (range: 42 – 82) in Group I and

64.64 ± 12.70 years (range: 42 – 85) in Group II.

Mean age was not significantly different between the

two groups (P = 0.334, 0.348 respectively). IOP rose

in 52 patients (mean 24 mmnHg) remained normal in

32 patients (mean 15.02 mm Hg). Table 1 compares

the Mean IOP 01 hour post-procedure and 3 days post-

procedure in the two groups.

CONCLUSION

We observed a significant IOP increase in the group

where prophylactic brimonidine was not given;

efficient IOP control was seen in the group where

brimonidine was used.

Table 1: Comparison of IOP in Two Groups.

Group I

(Treated)

Group II

(Untreated group)

IOP

Ethical Approval

The study was approved by the Institutional review

board/Ethical review board.

Before laser

1 hour post-procedure

3 days post-procedure

14.43 mm of Hg 14.43 mm of Hg

24.47 mm of Hg 24.10 mm of Hg

13.87 mm of Hg 23.02 mm of Hg

DISCUSSION

Conflict of Interest

PCO is the commonest cause of diminished visual

acuity post extra-capsular cataract surgery¹⁰. Nd: YAG

laser capsulotomy is the most authentic and confirmed

treatment of PCO¹¹. Some studies reported an

immediate improvement in visual acuity in majority of

cases treated by capsulotomy. In a review by

Weiblinger et al, gross visual acuity improved in 83–

94% and decreased in 3.5 – 6% of the cases¹². But the

procedure has its associated complications.

Commonest among them are an intra-ocular pressure

hike and macular edema. Intraocular pressure rise after

Nd: YAG laser capsulotomy is a complication reported

at different studies¹³. Studies in literature exhibit the

performance of various anti-glaucomatous agents in

the control of IOP. It was reported in a study that IOP

Authors declared no conflict of interest

Author Designation and Contribution

Muhammad Khizar Niazi; Professor: Study design,

Data collection, analysis, final review.

Ali Rauf: Study design, Data collection, analysis, final

review.

Yasser Nadeem: Study design, Data collection,

analysis, final review.

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