Long-Term Follow-up of a Case With Persistent Pupillary
Membrane Treated by
Sequential
Argon-YAG Laser Membranectomy
Ting-Hsuan Lin,
Tzu-Lun Huang, Pei-Yuan Su, Pei-Yao Chang, Ih-Jane Yang, Jia-Kang Wang
Ting-Hsuan Lin, Tzu-Lun Huang, Pei-Yuan Su, Pei-Yao
Chang, Ih-Jane Yang, Jia-Kang Wang,
Department of
Ophthalmology, Far Eastern Memorial Hospital, New Taipei City, Taiwan
Ting-Hsuan Lin,
Department of
Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan
Ih-Jane Yang, Jia-Kang Wang,
Department of
Medicine, National Yang Ming University, Taipei City, Taiwan
Jia-Kang Wang, Department of Healthcare
Administration and Department of Nursing, Oriental Institute of Technology, New
Taipei City, Taiwan
Jia-Kang Wang, Department of Medicine, National
Taiwan University, Taipei City, Taiwan
Tzu-Lun Huang, Institute of
Medical Sciences, Tzu Chi University, Hualien City, Taiwan
Pei-Yuan Su,
Department of
Medicine, Fu Jen Catholic University, New Taipei City, Taiwan
Correspondence to:
Jia-Kang Wang, Department of Ophthalmology, Far Eastern Memorial Hospital, 21, Sec. 2,
Nan-Ya South Road, Pan-Chiao District, New Taipei City, 220, Taiwan
Email:
jiakangw2158@gmail.com
Telephone: +886-2-89667000
Fax: +886-2-27903225
Received: July 8, 2015
Revised: August 26, 2015
Accepted: September 1, 2015
Published online: September 6, 2015
ABSTRACT
Purpose: To report a case with extensive
persistent pupillary membrane treated by sequential argon-YAG laser
membranectomy.
Case Report: A 33-year-old female had a prominent
persistent pupillary membrane obstructing the visual axis of the right eye,
thereby preventing measurement of refraction even after mydriasis. Her
uncorrected vision was 20/400. Firstly, the argon laser was used to
photocoagulate the part of the membrane adhering to the iris surface and so to
prevent any bleeding caused by the YAG laser. Secondly the YAG laser was used
to photodisrupt the membrane remnant attached to the iris. Mild pigment
dispersion was found in the anterior chamber, without associated
microhemorrhages after the laser treatments. Spontaneous reabsorption of the
free floating membrane occurred 1 week after the membranectomy. After an 8-year
follow-up period, her right corrected visual acuity increased to 20/40 with
high myopia. No ocular complications or membrane recurrence were noted.
Conclusion: Sequential argon-YAG laser
membranectomy may effectively be used to treat persistent pupillary membrane
without any long-term risk of major side effects.
© 2015 ACT. All rights reserved.
Key words: Iris; Persistent
pupillary membrane; Sequential argon-YAG laser membranectomy
Lin TH, Huang TL, Su PY, Chang PY, Yang IJ, Wang JK. Long-Term
Follow-up of a Case With Persistent Pupillary Membrane Treated by Sequential
Argon-YAG Laser Membranectomy. International
Journal of Ophthalmic Research 2015; 1(2): 66-68 Available from: URL:
http://www.ghrnet.org/index.php/ijor/article/view/1284
Background
Persistent pupillary membranes (PPMs) are a common congenital anomaly
seen in about 95% of newborns[1,2] and due to an incomplete
involution of the tunica vasculosa lentis[1]. The membranes
are seen originating at the collarette of the iris and either bridge the pupil
to the collarette on the opposite side or may have one end free floating[2].
They mostly do not require treatment since PPMs usually undergo considerable
atrophy during the first year of life[3]. However, dense membranes
that cause visual impairment must be removed.
Case REPORT
A 33-year-old female patient with bilateral PPM and high myopia was
seen in our clinic. The right eye had no previous treatment and the patient was
aware of longstanding blurred vision in the right eye. The PPM in the left eye
had been treated with surgical excision at the age of 9 years. This treatment
appeared to be successful with best-corrected visual acuity (BCVA) of 20/40,
although there was now a high degree of myopia (-16 D). The anterior and
posterior segments and intraocular pressure (IOP) in the right eye were normal
except for the prominent PPM (Figure 1), which was not associated cataract. Her
right uncorrected vision was 20/400. A retinoscope or auto-refractor could not
measure the refraction, even after mydriasis, due to obstruction by the dense
PPM. Visual acuity remained 20/400 after pinhole correction, and long axial
length measured by optical biometry (IOLMaster, Zeiss Co., Berlin, Germany) was
28.32 mm. Sequential argon-YAG membranectomy was performed to remove the PPM in
July 2006. Under topical anesthesia and dilated pupil conditions, the light was
focused with an Abraham capsulotomy lens. The argon laser (PUREPOINT®,
Alcon Laboratories Inc., Fort Worth, TX, USA) was used to photocoagulate the
part of the PPM attached to the iris surface to prevent bleeding caused by the
YAG laser. The argon laser settings were spot size 100 µm, energy 300 mW, and
duration 0.1 second for 30 applications (Figure 2). The Nd:YAG laser (3000-LE,
Alcon Laboratories Inc., Fort Worth, TX, USA) with energy set to 1-5 mJ for 30
applications was used to photodisrupt the PPM remnant adhering to the iris
(Figure 2). All laser procedures were completed in one session. Spontaneous
absorption of the free floating PPM had occurred by 1 week after the
membranectomy. Mild pigment dispersion was found in the anterior chamber,
without associated microhemorrhages. Increased IOP up to 25 mmHg was found one
hour after the laser treatments. The patient was treated with topical 0.5%
timolol twice a day and dexamethasone ophthalmic solution four times a day to
lower the IOP and the inflammation in the chamber. The patient recovered fully
without medical management 1 week after the laser therapy. After 8 years of
follow-up, her right BCVA was 20/40 with high myopia of -15 D and her right eye
(Figure 3) and left eye were free of recurrent or residual PPM. The appearance
of the pupil was not different between laser and surgically treated eyes.
Spectral-domain optical coherence tomography showed normal macular anatomy. No
ocular complications, such as cataract and hyphema, were noted.
Discussion
Before the era of ophthalmic
lasers, surgical excision was essential for removal of PPMs. The surgery was
technically simple, but might carry some operational risks, such as secondary
cataract, hyphema, infection, wound disruption, or even epithelial ingrowth[4-7].
In 1987, Vega et al[3] first successfully treated dense PPM
with Nd: YAG laser irradiation. The technique is noninvasive and effective, can
be performed in an outpatient clinic without the risk of intraoperative and
postoperative complications associated with conventional surgery, and the
period of vision recovery is quick, most likely one week. Kumar et al[4].
also reported the same results for the use of Nd: YAG laser membranectomy for removing
PPM. However, temporary microhemorrhages were found following photodisruption
of the remnant strands of PPM in two reports[3,4].
When our patient came to the
clinic for examination, an extensive PPM was discovered. Because of poor vision
not corrected by glasses, removal of the membrane was advocated. We used a
sequential argon-YAG laser method to remove the PPM without causing bleeding of
the iris. The method was inspired by the sequential argon-YAG laser iridotomy
procedure used to treat angle-closure glaucoma[8]. The argon laser
is a thermal laser, which can produce a coagulative effect on the surface of
the iris, thereby averting subsequent hemorrhage[9]. The Nd:YAG
laser is used to photodisrupt the PPM strands. Little deposition of dispersed
iris pigments occur in the anterior chamber following such laser treatment, and
this dispersion disappears the next day. When glaucoma occurs, it is mild,
temporary, secondary, and can be controlled medically. Large PPMs may remain
vascularized or persist as vascularized fragments that do not spontaneously
absorb after birth[10]. Following laser membranectomy, the free
floating non-vascularized PPM can disappear without sequelae in one week.
Although ours was the first attempt to use the modified laser technique for
removal of PPM, the good anatomical and visual results persisted long-term.
The stenopaeic effect of the
PPM may account for the lack of deprivation amblyopia. A circle at the center
of the membrane acted as a pinhole and prevented total obstruction of the
central visual axis. Visual acuity can improve after removal of the
membrane.
In conclusion, sequential
argon-YAG laser membranectomy is noninvasive, effective for removal of PPMs,
and prevents small hemorrhages that usually follow laser treatment. To our
knowledge, this is the first case of PPM managed by the modified laser
technique. The anatomical and visual improvement is long-lasting.
CONFLICT
OF INTERESTS
The authors have no conflicts of
interest to declare.
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Peer reviewer: Shengli Mi, Associate Professor, Room 102, J Building,
Tsinghua Campus, University Town, Nanshan district, Shenzhen, China.
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