Nghiên cứu phẫu thuật cắt dịch kính điều trị bong võng mạc do lỗ hoàng điểm TT TIENG ANH

MINISTRY OF EDUCATION AND TRAINING

MINISTRY OF HEALTH

HANOI MEDICAL UNIVERSITY

NGUYỄN KIẾM HIỆP

RESEARCH OF VITRECTOMY IN THE
TREATMENT OF RETINAL DETACHMENT
DUE TO MACULAR HOLE

Speciality: Ophthalmology
Code: 62.72.01.57

SUMMARY OF DOCTORAL THESIS

HÀ NỘI - 2021


THIS RESEARCH WAS CONDUCTED IN
HANOI MEDICAL UNIVERSITY

Research supervior:
Ass. Prof. PhD. Cung Hồng Sơn

Reviewer 1:

Reviewer 2:

Reviewer 3:

This thesis will be defended before a Thesis committee in
Hanoi Medical University.
At ……………………, …………./………/ 2021

This thesis may be found at
- National library
- Library of Hanoi Medical University


LIST OF PUBLISHED PAPERS RELATED TO THE
THESIS
1. Nguyễn
Kiếm Hiệp, Nguyễn
Thị
Phương Thảo.
Phacoemulsification on patients with severe myopia with cataracts
combined with retinal detachment and macular hole. Vietnam
medial journal, No 01 April 2020, p.184 - 188.
2. Nguyễn Kiếm Hiệp, Cung Hồng Sơn. Evaluation of vitrectomy
and removal of internal limiting membrane with inverted flap to
treat retinal detachment due to primary macular hole. Journal of
medical research, Vol. 137, No 1 2021, p.229 -235.
3. Nguyễn Kiếm Hiệp, Cung Hồng Sơn, Nguyễn Thị Phương Thảo.
OCT results on patients after surgery for retinal detachment due to
macular hole. Journal of medical research, Vol. 137, No 1 2021,
p. 236 - 242.
4. Nguyễn Kiếm Hiệp. Factors related to the outcomes of vitrectomy
for retinal detachment due to macular hole. Vietnam medial
journal, No 01, p.63 – 68.

1

INTRODUCTION
1. Necessity of the thesis
Retinal detachment associated with macular hole (MHRD) accounts for
0.5% of retinal detachment, the rate is higher in some ethnic groups,
reported in the Japanese and Chinese literature at 9% and 21%
respectively. MHRD occurs predominantly in highly myopic eyes but has
also been noted to occur after blunt ocular trauma. The difficulty in
determining whether a full or partial retinal macular hole is the cause of
retinal detachment has been emphasized by many authors. Sometimes
retinal detachment causing macular hole or vice versa is difficult to
determine because the patient presented with extensive retinal detachment
and macular hole.
The MHRD occurs in one of two cases: firstly, high myopia and
staphyloma account for 67.7% - 96.7% with myopia from -8.25D to 3.25D. In these cases, the macular hole is the tear leading to the retinal
detachment. Retinal detachment is predominantly at posterior pole or
extend anteriorly without other tears. In the second case, retinal
detachment was progressive, starting from periphery and then spreading
posteriorly. The stretching of the retinal tissue on the thin film during
detachment leads to the formation of a macular hole. Although its
pathophysiology is not fully understood, it is thought that MHRD in
highly myopic occurs due to 3 reasons:
Anteroposterior vitreous traction on the posterior pole due to a
posterior staphyloma
Tangential traction on the macula from contraction of the cortical
vitreous and epiretinal membranes
Reduced retinal adherence to the choroid due to retinal pigment

epithelial (RPE) atrophy
Surgery is the unique way to treat MHRD. Different surgical methods
have been described by many authors. In the past, macular infusion
combined with macular hole treatment by cryotherapy, electrocoagulation
or laser photocoagulation were the methods of early treatment of choice
for these eyes.
Today, a better understanding of retinal traction and advances in
vitrectomy have increased the success rate from about 50% to more than
90%. The choice of the surgical technique is based on vitreous status, with
or without staphyloma, and degree of macular changes such as
neovascularization or central choroidal atrophy, axial length, and disease
peripheral retinal disease. However, the anatomical successes but the


2
functional failures are challenging for surgeons. The reports in the
literature are largely retrospective, making direct comparisons of surgical
approaches difficult. Therefore, the optimal treatment of macular hole
retinal detachment remains controversial.
In the world as well as in Vietnam, failure of closure the macular hole
and recurrent retinal detachment, especially the visual results are often
disappointing, which is a challenge for ophthalmologists in general as well
as for retina specialist in particular. Therefore, there should be studies on
this issue to help ophthalmologists choose the appropriate method in each
case. That is why we carry out this research.
2. Objectives of the thesis
- Evaluate the surgical outcomes of retinal detachment due to macular hole.
- Analyze some factors related to surgical outcomes.
3. Scientific and practical significance of the thesis
- This is the first study on vitrectomy and removal of the inner limiting

membrane (ILM) in the treatment of RDMH in Vietnam with a sufficient
number of patients and relatively long follow-up.
- This study showed that the peeling of the ILM creating a reversible
flap without tissue loss provides a higher rate of macular hole closure and
better vision after surgery, explaining why previous surgeries were
anatomically successful but had little or no improvement in vision.
- The study reported highly successful outcomes on anatomy, retinal
reapposition and macular hole closure. Improved vision is an important
factor in helping patients improve their quality of life
- The study also analyzed the relationship between the success rate of
surgery with some factors: disease duration, preoperative visual acuity,
macular hole size, ocular axis length. In addition, a number of factors that
are not related to anatomical surgical results are also analyzed: age of the
patient, degree of retinal detachment before surgery, intraocular
tamponade.
4. Structure of the thesis:
The thesis is presented in 126 pages (excluding references and
appendices). It includes introduction (2 pages), overview (39 pages),
objects and methods (19 pages), results (31 pages), discussion (33 pages),
conclusions (2 pages),118 references.


3
Chapter 1: INTRODUCTION
1.1. PATHOLOGICAL MECHANISM RDMH
1.1.1. Definition of RDMH
Retinal detachment is a condition in which the nerve layer of the retina
is separated from the pigment epithelium due to accumulation of fluid in
the subretinal space.
RDMH accounts for a relatively low rate of 0,5 of all retinal

detachments and is mainly seen in patients with highly myopia.

Figure 1.1. Retinal detachment associated with macular hole13
1.1.2. Mechanism of RDMH
1.1.2.1. Factors that stablize the retinal
The outer part of the photoreceptors (cones and rods) is surrounded by
villi of the pigment epithelium, the cell adhesion between these two layers
is not tight, the normal virtual cavity exists and is maintained by many
factors. The first element is the hydrostatic gradient related to intraocular
pressure. The next and most important factor is the impermeability of the
retinal pigment epithelium and the continuous and active pumping of
water from the subretinal space back to the choroid. Lastly, the pigment
epithelium and the photoreceptor layer are bound together by a
glycoprotein complex present in the subretinal space.14
1.1.2.2. Risque factors of retinal detachment
Retinal tears and fluid movements in the vitreous cavity are necessary
conditions for retinal detachment. Retinal holes or tears deprive the retina of
its water-resistance and provide a pathway for fluid to pass directly into the
subretinal space. However, retinal detachment occurs only when there is
prior liquefaction of the vitreous and enough fluid went through the tears to
exceed the pump capacity of the pigment epithelium.
1.1.2.3. Mechanism of macular hole formation
The primary macular hole is formed by traction in front of the central


4
fossa of the vitreous cortex with tangential combined with antero-posterior
traction leading to the formation of the primary partial and total macular
hole. Primary macular holes occur mainly in elderly patients and have an
incidence of 0,03 to 0,05%. The incidence in women is three times higher

than in men.
Chronic macular edema associated with venous occlusion or diabetic
macular edema can also lead to a total macular hole. Relatively rare cases
of macular holes have been reported following electric welding and bright
light injuries. There have also been some case reports of macular holes in
both eyes after posterior capsule opening by YAG.
1.1.3. Etiology of retinal detachment due to macular hole
1.1.3.1. Staphyloma
Staphyloma is a clinical feature of pathological myopic eyes. It is a
focal dilatation of the sclera, choroid and pigment epithelium.
1.1.3.2. Atrophy of the choroid and retinal
As a result of elongation of the ocular axis and internal structures,
peripapillary crescent formation and choroidal atrophy are fairly common
features in highly myopic eyes. Areas of atrophy may be localized or
diffuse, with clear or irregular margins, appearing as isolated pale white
multifocal areas or fused together.
1.1.3.3. Macular retinoschisis
This is a separation of the retinal layers in the macula, resulting in
blurred vision and distortion. This macular retinoschisis can then lead to
the formation of a macular hole due to myopia and possibly retinal
detachment.
1.1.3.4. Macular hole
Macular hole is one of the complications of high myopia, accompanied
by staphyloma and choroidal atrophy. The occurrence of macular holes in
myopic patients also increases with age.
1.1.3.5. Retinal detachment associated with macular hole
This is considered to be the final stage of macular disease on high
myopia, of which the primary stage is retinoschisis. According to Siam A
(1969) there were no cases of RDMH without staphyloma except patients
with another peripheral tear.

Retinal detachment is usually initially localized to the posterior pole in
the staphyloma area, then gradually spreads to the peripheral retina.
According to Akiba et al (1999) in 37 eyes with retinal detachment, 36
eyes had staphyloma and the retinal detachment was localized in this area.
Only one eye had retinal detachment without staphyloma.1 Thus, in cases


5
of RDMH in patients with high myopia, staphyloma plays a more
important role than antero-posterior traction of the macular vitreous.
1.1.4. Clinical and imaging features of RDMH
1.1.4.1. Clinical features of RDMH
* Age and gender
Retinal detachment due to macular hole is common in elderly patients. A
study of Ripandeli et al (2004) including 120 patients with retinal detachment
due to myopic macular hole had the mean age of 53.6 ± 6.4 years, the lowest
was 42, the highest was 68 years old.
Most of the studies showed that retinal detachment due to macular hole
occurs predominately in female patients. A research by Lim et al (2014)
included 114 patients with 79 female patients (69.3%).
* Visual acuity
Retinal detachment due to myopic macular hole directly affects the
macula, so most cases have very poor vision. Feng's research (2012)
showed that only 10,3% patients with retinal detachment due to myopic
macular hole had visual acuity above 20/200, 58,6% had finger counting
vision, 10,3% had hand movement and 3,4% had light perception.
* Degree of myopia
Primary retinal detachment due to macular hole occurs mostly in myopic
patients. The rate of macular hole patients with retinal detachment is 0,6%,
but this rate increases to 10% if the patient has high myopia. Severe myopia

or pathological myopia is defined when the myopia is greater than -6.0D or
ocular axis is above 26mm.
* Symptoms
Patients with RDMH often have a variety of previous macular
symptoms. At first, symptoms appear mild and vague, such as blurred or
distorted central vision and appear only when reading or driving. Typical
functional symptoms of macular hole are macular syndrom: blurred vision,
central scotoma, visual distortion and chromatic disturbance.
Accompanying signs include floaters and light flashes.
* Signs
- Posterior staphyloma
- Posterior hyaloid detachment
Posterior vitreous detachment often occurs in patients with high
myopia. The typical sign of vitreous detachment on ophthalmoscopy is the
appearance of a Weiss' ring. A research by Soheilian et al showed that
100% of eyes with RDMH had liquefied vitreous and posterior vitreous
detachment.


6
- Retinal detachment
Ligou Feng et al (2012) also showed a low rate of total retinal
detachment (6,9%), but nearly total retinal detachment accounted for the
majority (55,2%), the remaining 37,9% had localized posterior retinal
detachment.
- Macular hole
According to Koybayashi et al (2001), a study on patients with macular
holes stages III and IV showed high myopia patients with ocular axis over
26 mm.
1.1.4.2. Imaging of macular retinal detachment due to macular hole

On ultrasound and OCT studies, Li et al (2009) reported 231 eyes with
myopic macular hole retinal detachment showing 38,8-43,6% localized
posterior retinal detachment, 14,9-22,8% posterior retinal detachment with
1 quadrant, 17,8-25,6% posterior retinal detachment with 2 quadrants,
12,9-14,9% near-total retinal detachment (posterior detachment with 3
quadrants) and the remaining of about 3-5,8 % total retinal detachment.
1.2. VITRECTOMY IN THE TREATMENT OF RDMH
1.2.1. The evolution of vitrectomy
Since the appearance of the first vitrectomy system in the 1970s until
now, the general principles have remained unchanged. The vitrectomy
system must ensure an efficient cutting-aspiration cycle and not
compromise the retina and vitreous. On the other hand, the system must
compensate for the amount of fluid removed and inserted into the globe to
maintain the balance of intraocular pressure.
1.2.2. General principles of vitrectomy in RDMH
Vitrectomy in the treatment of RDMH has the following objectives:
− Create a space in the vitreous chamber for endotamponade during
surgery (air, perfluorocarbon solution) and postoperatively (silicone oil,
expanding gas).
− Allow the instrument to come into direct contact with the retina to
peel off the proliferative membrane, the inner limiting membrane and
aspirate the subretinal fluid...
− Separate the posterior vitreous cortex and the posterior hyaloid
membrane if adhesion is present.
− Separate the vitreous base, releases the vitreous body of anterior
structures (ciliary body, vitreous capsule...) and detaches the anterior
hyaloid membrane if possible.
− Release vitreous’ pull on the edge of the tear.
− Remove the cataract to enhance the view of the fundus.

7
− Peel off the inner limiting membrane and preretinal membrane.
1.2.3. Complications related to surgery
- Retinal tearing in surgery
- Changes in pigment epithelium
- Recurrent retinal detachment
- Cystic macular edema, choroidal neovascularization, endophthalmitis
- Recurrent macular hole
- Increased intraocular pressure
- Visual field loss
- Cataracts
1.3. SOME FACTORS RELATED TO SURGICAL RESULTS
1.3.1. General characteristics of the study group
1.3.1.1. Age and gender
According to Chen et al (2015), the ratio female/male patients was 3/1
with the mean age of the group of patients being 61,25 years old.
Lam (2006) and Nishimura (2011) also showed that age is not a factor
related to the outcomes of surgery.
1.3.1.2 Duration of disease
Time from ignition of symptoms to diagnosis and surgery is an
important factor affecting the outcomes because retinal detachment is an
emergency. According to another study by Lim et al, the duration was 5,2
± 10,6 months.
1.3.1.3 Visual acuity
According to Nishimura (2011) initial visual acuity is related to the
anatomical outcomes of surgery. Lim (2014) showed that the lower the
visual acuity, the lower the possibility of retinal reapposition and macular
hole closure after surgery. Poorer baseline visual acuity represents more
severe ocular damage, so recovery from surgery is more limited than in

eyes with less damage.
1.3.1.4. Ocular axial length
According to Ikuno Y (2003), the rate of macular hole closure after
surgery in the long axial group is lower. It has been hypothesized that the
retina surface is insufficient to cover the staphyloma, even after retinal
reapposition in high myopia. On OCT, they also reported that eyes with
retinal reapposition around the border of the hole after surgery still have
very flat retinal detachment at the posterior pole.
Thus, the axial length of the globe is an important factor in the
prognosis of vitrectomy for retinal detachment due to macular hole.


8
1.3.1.5. Macular hole size
According to Kim DY (2021) in eyes with smaller macular holes, the
rate of recurrent retinal detachment was low, macular hole closure was
also a premise to avoid recurrence of retinal detachment after surgery.
According to Xie and Lei (2013) in a study on 28 eyes with vitrectomy and
intraocular silicone oil tamponade to treat retinal detachment due to macular
hole in high myopia eyes, all the 7 eyes with recurrent retinal detachment had
macular holes larger than 600 µm.
1.3.1.6. Peeling of internal limiting membrane
Theo Chatziralli I (2021), peeling of the ILM releases traction force on
the macula and stretches the retina, promoting the closure of the macular
hole and reattachment the retina, the rate of retinal reattachment after
surgery ranged from 91,8% to 97,1%.
The technique of using an inverted flap when peeling the ILM for large
macular hole was reported in 2010 by Michalewska et al (2010).
According to Đỗ Văn Hải (2019), the success rate of macular hole closure
using vitrectomy to peeling the ILM in patients with macular hole without

retinal detachment was 100%, the diameter of the peel area recommended
by the authors was not less than 1.5 times of the optic disc diameter.
1.3.2. Factors related to functional outcomes
1.3.2.1. Duration of disease and visual outcomes
According to Lam et al (2006), the longer the disease period was, the
larger the size of the macular hole was and the longer the duration of
retinal detachment was, the more damage was done to the pigment
epithelium, which is already atrophied in myopic eyes, so it limits the
ability to close the hole and reattach the retina. Lam et al found that the
success rate decreased with the longer duration of the disease.
1.3.2.2. Degree of retinal detachment
According to Blodi CF et al (1984), the mean postoperative visual
acuity in groups with different preoperative degree of retinal detachment
did not differ.
1.3.2.3. Preoperative size of macular hole
Lam et al also found that the eyes with better anatomical success had
better functional improvemen. The postoperative best corrected visual
acuity in the group of patients with macular hole closure was 1,32
logMAR, significantly higher than the non-closure group (0,45 logMAR)
during follow-up.
Như vậy, việc đánh giá kích thước lỗ hồng điểm trước phẫu thuật là
một thao tác cần thiết để tiên lượng cho thành công của phẫu thuật cả về
giải phẫu và chức năng mắt.
Thus, the preoperative assessment of macular hole size is essential to
predict the success of surgery both in terms of anatomy and function.


9
1.4. LITERATURE ON TREATMENT OF RDMH IN THE WORLD
AND IN VIETNAM

1.4.1. International literature
In 1982, Gonvers and Machemer were the first to introduce the
technique of vitrectomy and intraocular gas tamponade to treat retinal
detachment due to macular hole. Since then, many authors have studied
vitrectomy, gas tamponade, intraocular silicone oil and face-down position
for treatment of retinal detachment due to macular hole and reported very
good anatomical and functional outcomes.
In the 2000s, several authors such as Uemoto (2003), Nakanishi
(2008) reported vitrectomy combined with removal of the inner limiting
membrane to treat retinal detachment due to macular hole.
In recent studies, the anatomical and functional success rate is
generally 90%.
From 2007 to 2010, Oie et al, Kusaka S, Li KK used membrane dye, so
that the removal of the inner limiting membrane is easier, resulting in a
higher success rate of surgery.
1.4.2. In Vietnam
In recent years, some authors have studied and evaluated the results of
vitrectomy to treat macular hole pathology such as: Cung Hong Son
(2011) reported the anatomical success rate achieving up to 92.3% and
61.5% improved visual acuity on 2 rows after surgery. Bui Cao Ngu
(2013) has studied on macular hole concussion and gave positive results
with 78.9% anatomical success, 60.1% improvement in function. Most of
the authors used the technique of vitrectomy and peeling ILM, inflate the
intraocular gas, giving a high success rate both anatomically and
functionally. Do Van Hai (2019) “Research on vitrectomy for treatment of
macular hole” showed that the rate of macular hole closure after
vitrectomy with inner limit vitrectomy was from 87-90%.
In 2021, Nguyen Minh Thi et al. stated the clinical characteristics of
macular hole due to blunt trauma ocular, showing that the poor initial
visual acuity is related to the large macular hole size, measurement and

calculated on OCT point towards a poor prognosis for anatomical and
functional recovery after treatment. However, there has not been a study
on surgical treatment of retinal detachment due to macular hole, so we
conducted this study.

Chapter 2
PATIENTS AND METHODS
2.1. Patients
Study subjects include patients undergoing vitrectomy to treat retinal
detachment due to macular hole.


10
2.1.1. Inclusion criteria
Patients with macular hole retinal detachment treated with vitrectomy
who have the following criteria:
- Visual acuity from light perception and better
- Over 18 year old.
- Accept to participte in the study.
2.1.2. Exclusion criteria
- Retinal detachment due to macular hole with accompanying retinal tears.
- Other ocular diseases compromising the examination, surgery and
outcomes such as pterygium grade 3 or 4, dense corneal scar.
- The patient underwent cataract surgery but was unable to place an
IOL during surgery.
- Weak or seriously illed patients.
- Uncooperative patients.
2.1.3. Venue
Patients were examined before surgery, underwent surgery and were
followed-up at the National Eye Hospital.

2.1.4. Time
- We selected patients according to the inclusion criteria during the
period from 2015 to the end of 2019.
2.2. Methods
2.2.1. Study design
Clinical intervention study design with no control group.
2.2.2. Sample size and sampling
- Sample size:
Formula:

- n : Sample size.
- p1 = 100%: pre-operative rate of retinal detachment .
- p2 = 86% : post-operative rate of retina reattachment1
- ES: Effect size
- α : Statistical significance level with α = 0,05
- ß : Test power with 1- ß = 0,75
Calculated according to the formula, the minimum sample size is 47 eyes.
- Sampling: patients were selected consecutively during the duration of
the study until the sample size is reached, according to the patient
inclusion criteria.


11
2.2.3. Study conduction
2.2.4. Study equipment
- Clinical examination instruments and imaging equipment
- Surgical equipment
2.2.5. Study protocol
Each patient was included in the study according to the following
procedure:

Patient with suspected retinal detachment comes to the clinic

Imaging

Clinical examintion

Confirm diagnosis, indication for surgery

Vitrectomy and removal of internal limiting membrane
Combine Phacoemulsification and IOL placement when indicated

Follow-up immediately after surgery, 1 month, 3 months and every
3 month for at least 9 months

Data collection, processing and analysis

Objective 1
Evaluate the surgical outcomes
of retinal detachment due to
macular hole.

Objective 2
Analyze some factors related
to surgical outcomes.


12
Chapter 3. RESULTS
3.1. Characteristics of patients
3.1.1. Age and gender

Among the study group, 75% of the patients were female, 25% were
male, the difference was statistically significant with p < 0,001.
The mean age of the study group was 62,60 ± 7,66 years old. The
number of patients in the age group over 50 to under 70 accounted for the
highest rate of 80,8%, the group of patients aged 70 years and older
accounted for 17,3%, patients aged 50 and under accounted for only 1,9%.
3.1.2. Preoperative visual acuity
The mean preoperative patient's visual acuity was 1,98 ± 0,31 logMAR
(Counting finger at 0,3m), ranging from 1,3 logMAR (20/400) to 2,4
logMAR (hand movement at 0.1m).
Most of the patients with preoperative visual acuity ≤ Counting fingers
at 1m accounted for 73,1%, the group with Counting fingers at 1m 20/400 accounted for 19,2%, the group with the best acuity 20/400 20/100 accounted for 7,7%, no patient had visual acuity ≥ 20/100. The
difference was statistically significant with p < 0,0005.
3.1.3. Degree of retinal detachment
Table 3.1. Degree of retinal detachment
Number of
Degree of retinal detachment
%
p
eyes
Localized posterior detachment
39
75,0
Posterior detachment with 1 quadrant
8
15,4
< 0,0005
Posterior detachment with 2 quadrants
5
9,6

Total
52
100
Localized retinal detachment around the macula accounted for 75,0%.
8 cases had larger detachment in 1 lower temporal quadrant (15,4%), 5
cases of extensive detachment in 2 lower quadrants (9,6%). The difference
was statistically significant with p < 0,0005.
3.1.4. Axial length
Table 3.2. Axial length
Axial length
Number of eyes
%
p
< 24mm
2
3,8
≥ 24 - < 26mm
5
9,6
< 0,0005
≥ 26mm
45
86,5
Total
52
100
The average axial length of the study group was 28 ± 2 mm, in which
the smallest was 23mm and the highest was 32,5mm.

13
3.1.5. Preoperative characteristics of macular hole
3.1.5.1 Size of macular hole
Table 3.3. Size of macular hole
Preoperative visual
Mean size of macular
Number of eyes
acuity
hole (µm)
(%)
≥ 20/400 - < 20/100
648
4 (7,7)
≥ ĐNT 1m - <20/400
679
10 (19,2)
< ĐNT 1m
702
38 (73,1)
Total
693
52 (100)
The difference in preopevative visual acuity between groups with
different macular hole sizes was statistically significant, with p < 0,05.
The larger the macular hole size was, the lower the preoperative visual
acuity was.
3.2. Surgical outcomes
3.2.1. Anatomical outcomes
3.2.1.1. Retinal outcomes
19.2

80.8

Áp hoàn toàn

Bong tái phát

Figue 3.1. Retinal anatomical outcomes
After surgery, eyes with complete retinal reattachment accounted for
80,8% (42 eyes), the number of eyes with recurrent retinal detachment
during the follow-up period accounted for 19,2% (10 eyes). The difference
in retinal anatomy after surgery was statistically significant with p <
0.0001.
3.2.1.2. Postoperative anatomical outcomes of macular hole
Table 3.4. Anatomical outcomes of macular hole
Anatomical outcomes of
Number of
%
p
macular hole
eyes
Total closure
32
61,5
Reduced size
20
38,5
0,096
Non-closure
0

0
Total
52
100


14
On postoperative clinical follow-up examination, we found that 32/52 eyes
(61,5%) had complete macular hole closure, the remaining 20/52 eyes had
macular holes reduced in size compared to before surgery, accounting for
38,5%. The difference was not statistically significant with p > 0,05.
3.3. Functional outcomes
3.3.1 Visual acuity outcomes
Table 3.5. Mean visual acuity in the last follow-up
Time
Preoperative
Postoperative
p
Mean visual acuity
1,99
1,35
< 0,0001
(logMAR)
Visual acuity on admission to the hospital before surgery had an
average value of 1,99 ± 0,31 logMAR (Hand movement 0,3m), ranging
from 1,3 logMAR (20/400) to 2,4 logMAR (Hand movement 0,1m) ).
The mean postoperative visual acuity at the last visit was 1,35 ± 0,26
logMAR (≈20/400), ranging from 0,6 logMAR (20/100) to 2,1 logMAR
(Counting fingers 0,5m). Postoperative visual acuity was significantly
higher than before surgery with p < 0,0001.

After surgery, the group of patients with visual acuity at 20/400 20/100 accounted for the highest rate of 51,9%, followed by the group of
patients with visual acuity at 1m - 20/400, accounting for 44,2%. There
was 1 case of high visual acuity above 20/100 and 1 case less than
Counting fingers at 1m (1,9%).
3.4. Factors related to surgical outcomes
3.4.1. Factors related to anatomic outcomes
3.4.1.1. Duration of disease
The difference in retinal anatomy after surgery between groups of
patients with different disease onset time was statistically significant with
p = 0,04. Thus, with a shorter duration of disease, the rate of retinal
reattachment after surgery is higher than in the group with a long duration
of disease.
The difference in macular hole anatomy after surgery between the two
groups of patients with different disease onset time was statistically
significant with p = 0,045. With a short duration of disease, the rate of
complete macular hole closure is higher than that of those who has long
duration.
3.4.1.2. Preoperative visual acuity
Retinal anatomy after surgery in different groups of vision at time of
admission had a statistically significant difference with P = 0,047. The lower
the visual acuity, the higher the rate of recurrent retinal detachment was.


15
The difference in macular hole anatomy in different groups of visual
acuity when admitted to the hospital was statistically significant with p =
0,0084. The lower the visual acuity on admission, the less likely it is to
close the macular hole completely.
3.4.1.3. Degree of retinal detachment
Retinal anatomy after surgery in groups with different degree of retinal

detachment had no difference with p = 0,351. The rate of retinal
reattachment after surgery was independent of the degree of retinal
detachment before admission.
3.4.1.4. Axial length
Retinal anatomy after surgery in different groups of axial length was
statistically significant with p = 0,038 < 0.05. The longer the axis, the
higher the risk of recurrent retinal detachment after surgery.
3.4.1.5. Preoperative size of macular hole
Retinal anatomy after surgery in different preoperative macular hole
size groups had a statistically significant difference with p < 0,05. All eyes
with macular hole size < 600 µm have retinal reposition after the first
surgery. Up to 10/34 eyes with macular hole ≥ 600 µm have recurrent
retinal detachment after the first surgery. Thus, the larger the macular hole
size. the higher the risk of recurrent retinal detachment.
The difference of macular hole anatomy after surgery in the different
preoperative macular hole size groups was statistically significant with p =
0,013. The smaller the macular hole before surgery, the easier it is to close
completely after surgery.
3.4.1.6. Technique of internal limiting membrane peeling
For the method of removing the internal limiting membrane, the main
technique used was inverted flap in 51 eyes (98,1%). Only 1 case didn’t
use invert flap (1,9%) and in this case the macular hole only reduced in
size. The difference was statistically significant with p = 0,202 (phi
cramer's test).
3.4.1.7. Condition of internal limiting membrane during surgery
In surgery, the percentage of eyes of which the inner limit membrane
was completely removed accounted for 80,8%, the remaining 19,2% of the
patients only had the inner limit membrane removed partially. The more
the inner limiting membrane is peeled off to the correct size, the better the
chance of complete closure of the macular hole

16
3.4.2. Factors related to functional outcomes
3.4.2.1. Duration of disease
Table 3.6. Relationship between duration of disease and vision outcomes
Visual acuity after surgery and the degree of visual improvement
between groups of different duration of disease less than 6 months and
over 6 months did not have a statistically significant difference, with p =
0,456.
3.3.2.3. Preoperative size of macular hole
Table 3.7. Relationship between preoperative size of macular hole and
visual outcomes
Mean size
Number
Visual outcomes
of macular
of eyes
p
hole (µm)
(%)
≥ 20/100
468
1 (1,9)
≥ 20/400 - <20/100
635,4
27 (51,9)
≥ Counting finger 1m - <20/400
761,6
23 (44,3)

0,009
< Counting finger 1m
946
1 (1,9)
Total
738,07
27 (100)
The average macular hole size of the group with visual acuity < 20/400
- < 20/100 was smaller than the group with visual acuity ≥ 1m - < 20/400.
The larger the macular hole, the lower the postoperative visual outcome.
The difference was statistically significant with p = 0,009.
Chapter 4
DISCUSSION
4.1. Characteristics of patients
4.1.1. Age and gender
In our study, the group of patients aged 50-70 years old accounted for
the highest percentage (80,8%) with mean age of 62 years old (49-79 years
old). The number of female patients was three times higher than that of
male patients. The distribution of disease in age groups did not differ
between the sexes with p = 0,462. The report of Chen et al (2015) also had
a female/male ratio of 3/1 with mean age of patients being 61,25 years old.
4.1.1.1. Preoperative visual acuity
Table 4.1. Properative visual acuity in several studies
Prioperative visual
Author
n
acuity
Nishimura (2011)
24
1,8

Lim (2014)
114
1,8
Chen (2016)
40
1,72
Kakinoki (2019)
110
1.38


17
NK Hiệp (2019)
52
1,98
The preoperative visual acuity of the study group was low with 1,98
logMAR, which is equivalent to the acuity of Lim (2014) or Nishimura
(2011) or Chen (2016) in patients with retinal detachment due to macular
hole. However, it was much lower than that of patients with only macular
hole in the study of Đỗ Văn Hải (2019) with mean visual acuity of 1,12 ±
0,4logMAR. This shows that this condition affects vision more seriously as
it also causes retinal detachment in addition to damage to the central retina.
4.1.1.2. Degree of retinal detachment
The degree of retinal detachment due to primary macular hole is
mainly localized retinal detachment around the macula, accounting for
75%. We also recorded 8 cases with larger detachment in 1 lower
temporal quadrant (15,4%), and 5 cases with 2 lower quadrants (9,6%).
The difference was statistically significant with p < 0,0005. This is
different from other surgical retinal detachments.
4.1.1.3. Axial length

We evaluated the refraction through the axial length on ultrasound
mode B with a cutoff point of 26 mm corresponding to the definition of
high myopia of - 6.00 diopter. Axial length of the study group was mostly
that of severe myopia ≥ 26mm (86,5%) with an average axial length of
28mm (23-32,5mm).
Macular holes have always been considered an important cause of
central vision loss and can be a serious complication in patients with high
myopia, axial length greater than 26,5 mm, and/or refraction above -6.0
diopter. The prevalence over time of macular holes in highly myopic
individuals is 6,26% to 8,4%. The rate of retinal detachment due to
macular hole increases with more severe myopia (9-21%). Eyes with
myopia between -3,25 and -8,0 diopters are estimated to develop macular
hole retinal detachment of 67,7%, while the rate of retinal detachment due
to macular hole can be as high as 97,6% in myopic eyes above -8,25
diopters.
4.1.2. Preoperative characteristics of macular hole
4.1.2.1. Size of macular hole
The size of the macular hole was measured between the two edges of
the macular hole in the slice with the largest diameter on OCT. The group
with hole size ≥ 600 µm accounted for the highest proportion 65,4%, the
group with hole size from 400 - < 600 µm accounted for 32,7%, the lowest
was the group with hole size ≤ 400µm with 1,9%. The difference in hole
size in 3 study groups was statistically significant with p < 0,001.
In 52 patients of the study group, the average macular hole size was
693,96 ± 170,10 µm (385 µm - 1005 µm). This result is similar to the
report of Do Van Hai (2019) in eyes with macular hole without retinal


18
detachment, with the average macular hole size of 620,1 µm ± 152,84 (133

µm – 1242 µm) and the group with the highest rate is the group with macular
hole size ≥ 400 µm (76.3%). These studies all have vietnamese patients, so
there are similarities in patient characteristics and medical conditions.
4.1.5.4. Stage of macular hole
In the study group, there were no cases in early stage 1-2. There were 4
patients (7,7%) in stage 3 and 48 cases (92,3%) in stage 4. Thus, the
majority of patients with macular hole in stage 4 - the late stage, which
explains the poor visual acuity on admission and leads to retinal
detachment complications.
4.2. Surgical outcomes
4.2.1. Anatomical outcomes
4.2.1.1. Postoperative retinal outcomes
The rate of complete retinal reposition after 1 surgery was 80,8%,
comparable to the results of Kakinoki et al at 85%, and Lim at 86%. Thus,
after surgery, the majority of patients achieved the desired retinal
outcomes.
4.2.1.2. Postoperative anatomical outcomes of macular hole
On clinical examination and postoperative follow-up, we found that the
percentage of patients with fully closed macular hole was 32/52 eyes
(61,5%), the rest was reduced in size compared to before surgery and no
eye was without shrinkage of macular hole.
4.2.2. Functional outcomes
4.2.2.1. Visual acuity outcomes
Visual acuity on admission to the hospital before surgery had an
average value of 1,99 ± 0,31 logMAR (Counting finger 0,3m), ranging
from 1,3 logMAR (20/400) to 2,4 logMAR (Hand movement 0,1m). The
mean postoperative visual acuity at the last visit was 1,35 ± 0,26 logMAR
(20/400), ranging from 0,6 logMAR (20/100) to 2,1 logMAR (Counting
finger 0,5m). Thus, after surgery, the visual acuity improved with a higher
mean visual acuity than before surgery, which was statistically significant

with p < 0,0001.
4.3. Factors related to surgical outcomes
4.3.1. Factors related to anatomic outcomes
4.3.1.1. Duration of disease
Differences in retinal anatomy and macular hole after surgery between
groups of patients with different disease onset time were statistically
significant. The group of patients with a disease duration of less than 6
months had the rate of postoperative retinal reapposition in 38/47 eyes
(80,9%) and the rate of complete closure of the macular hole was 31/47 eyes
(66%), significantly higher than the group with longer disease duration, with
anatomic success rates of the retina and macular hole of 80% and 20%,


19
respectively. Thus, with shorter duration of disease, the rate of retinal
reattachment and macular hole closure after surgery is higher than the group
with long duration of disease, similar to the results of Lam et al (2006). We
chose the cutoff point of 6 months and found that the surgical results were
significantly different, so we can apply this milestone to recommend for
similar cases.
4.3.1.2Visual acuity
The percentage of complete retinal reattachment in groups with
different visual acuity when admitted to the hospital was statistically
significant with p = 0,047. The group with visual acuity from Counting
fingers at 1m to 20/400 had the highest rate of complete retinal
reattachment after surgery of 90%, the group below counting fingers at 1m
had a lower rate of 78,9% and the lowest rate (75%) belong to the group
with visual acuity from 20/400 to 20/100.
The difference in macular hole anatomy in the groups of visual acuity
when admitted to the hospital was statistically significant with p = 0,0084.

The group with the best vision (20/400-20/100) had the highest rate of
macular hole closure after surgery (75%), the remaining groups had lower
rate of only 70% and 57,9 %.
Như vậy, thị lực ban đầu có liên quan tới kết quả giải phẫu của phẫu
thuật. Thị lực càng kém thì khả năng áp võng mạc và đóng lỗ hồng điểm
sau mổ càng thấp.
Thus, primary visual acuity is related to the anatomical outcomes of
surgery. The lower the visual acuity, the lower the possibility of retinal
reattachment and macular hole closure after surgery.
4.3.1.3. Degree of retinal detachment
In several reports that discussed the extent of retinal detachment due to
macular hole in highly myopic eyes and anatomical success, the initial rate
of retinal reattachment in eyes with a large detachment was only 46% and
84%, respectively, the rates in eyes with retinal detachment in 1 to 4
quadrants are 60% and 100%. These reports mentioned that the area of
retinal detachment before surgery is not a risk factor for initial success.50
Our study also did not find a significant difference between the degrees of
retinal detachment and initial surgical success. This rate in the group of
posterior retinal detachment was 84,6%, the group of posterior retinal
detachment with one quadrant and two quadrants had this rate of 62.5%
and 80%, respectively.
However, the area of retinal detachment has an effect on the ability to
close the macular hole after surgery. The wider the retinal detachment, the
lower the probability of closing macular hole, with p = 0,04. The wide
detachment group including the posterior pole and one to two quadrants
had only 25% and 60% closure rates, respectively, while this rate in the


20
posterior pole only group was 69,2%. However, Nakanishi did not find

this association. The author explained that because the eyes that had
macular hole closure after surgery in his study were severe myopia
degeneration, and only a few patients had OCT, the results did not fully
reflect this relationship.50
4.3.1.4. Axial length
In this study, we also found that the longer the axis, the higher the
chance of retinal detachment recurrence after surgery. Recurrent retinal
detachment was only seen in eyes with ocular axis longer than 26mm
(10/45 eyes; 22,2%) but not in eyes with short axis and this difference was
statistically significant. This result is similar to the study of Lam et al with
success rate after surgery in eyes with axis less than 27mm is 6 times
higher than those with axis above 27mm. The authors reasoned that in
eyes with a long ocular axis, the extension of the retina may not be
sufficient to cover the posterior length of the sclera, resulting in
disproportion between these tissues. When this detached and insufficient
retina is pressed against the posterior wall by intraocular gas, the retina,
especially around the macular hole, can become centrifugally stretched,
preventing its ability to close or even rupture, promoting the reopening of
macular hole.
Thus, the axial length of the eyeball is an important factor in the
prognosis of vitrectomy for retinal detachment due to macular hole.
4.3.1.5. Size of macular hole
The size of the macular hole is a factor that reflects the severity of the
macular hole that needs to be analyzed in relationship with the outcomes
and is also the goal of treatment because it is necessary to reduce the size
and close the hole. Macular hole closure is also the premise of avoiding
the recurrence of retinal detachment after surgery.
We found that eyes with smaller macular holes had a statistically
significant lower rate of recurrent retinal detachment with p = 0,038. Holes
less than 600 µm in size did not have recurrent retinal detachment after

surgery. All eyes with recurrent retinal detachment had macular holes
larger than 600 µm. Xie and Lei (2013) similarly concluded that large
macular hole is a risk factor for recurrent retinal detachment when
performing vitrectomy and intraocular silicone oil tamponade for retinal
detachment due to macular hole in highly myopic eyes.
Smaller macular holes are more likely to close than larger sized
macular holes. 100% of macular holes under 400 µm closed completely
after surgery, with the closing rate of larger holes lower, of 88,2% in the
400-600 µm group and 47,1% in the over 600 µm group.It is clear that
small macular holes is easier to reduce the size than large ones.
4.3.1.6. Technique of internal limiting membrane removal


21
Removing the inner limiting membrane releases traction on the macula
and stretches the retina, promoting closure of the macular hole and
repositioning the retina, so 100% of the patients in the study had internal
limiting membrane removal during surgery. The majority of patients had
the technique of inverted flap (98,1%). To evaluate the association of this
technique with the anatomical success of the macular hole, we compared
the anatomical results of the groups of patients with or without the
application and found that there was no difference in the groups with or
without inverted flap with p = 0,202. However, in our study group, there
was only 1 eye with internal limiting membrane removal without the use
of inverted flap and in this case the macular hole only decreased in size,
but did not close completely.
The technique of using an inverted flap when removing the inner limit
membrane was reported in 2010 by Michalewska et al (2010) for large
macular hole. In this procedure, a limited portion of the membrane is left
and the flap is flipped upside down to cover the macular hole or can be

inserted into the hole, providing a framework for repair and closure. The
authors concluded that the inverted flap technique reduced postoperative
macular hole opening rate and improved the rate of macular hole closure
by up to 98%. Recently, this technique has been shown to be effective
both anatomically and functionally in the treatment of macular hole in
myopic eyes with or without retinal detachment with success rates ranging
from 91,7 to 97,8%. The inverted flap of the limiting membrane in cases
of idiopathic macular hole and myopic macular hole can act as a support
frame, stimulating glial cell proliferation and enhancing macular hole
closure and retinal reattachment. The inverted flap technique can restore
macular structure, as glial cell proliferation can reposition peripheral
photoreceptors to the center and provide an environment for new receptors
to be position near the macula. In addition, the interner limiting membrane
can supply collagen types IV, fibronectin and laminin, as well as activate
Müller cells to produce neurotrophic factors on the surface of the interner
limiting membrane, leading to closure of the macular hole.
4.3.1.7. Condition of internal limiting membrane in surgery and surgical
outcomes
The benefits of internal limiting membrane removal are thought to
derive from complete removal of the membrane, residual vitreous cortex
and cellular components, and all retinal traction associated with these
factors. In the study of Lam et al on surgical treatment of macular hole
with retinal detachment, when adjusting for other prognostic factors, the
author found that simultaneous internal limiting membrane complete
removal was related to higher anatomical success. Other studies have also
demonstrated a high success rate with internal limiting membrane removal


22
in the surgical treatment of retinal detachment due to macular hole.

Our results also showed that when the internal limiting membrane was
completely peeled off, the rate of complete macular hole closure was
higher. In surgery, the percentage of eyes that had completely removal of
the internal limiting membrane was 80,8%, the remaining 19,2% could
only partially be removed. The group that had complete removal of
internal limiting membrane had a complete closure rate of 73,7% (31
eyes), significantly higher than the group with only partial removal of 10%
(1 eye) with p = 0,001.
However, it is relatively difficult to completely remove the internal
limiting membrane from the thickened retina without causing damage to
the retina. In this study, 19,2% of the patients had only partial removal of
the internal limiting membrane. The ability to completely remove the
internal limiting membrane depends on many factors such as the degree of
dye staining, experiences of the surgeon, equipments and instruments as
analyzed above.
From the surgical process and the results of the study, we found that
the internal limiting membrane removal affects the anatomical results of
the macular hole after surgery. The internal limiting membrane captures
the dye better, the membrane is completely peeled off and the inverted flap
technique is used for better macular hole closure, but this process also
requires certain conditions in terms of human and material resources.
4.3.2. Factors related to functional outcomes
4.3.2.1. Duration of disease and visual outcome
Anatomically, we found that the longer duration of illness had a
significant effect on the low success of surgery in terms of retinal
reattachment rate, macular hole closure rate and postoperative macular
hole size. However, functional success did not appear to be different
between groups different duration of illness. Although after surgery, the
average visual acuity of the patients improved, but there was no difference
in the level of improvement in the 2 groups of patients with disease

progression above and below 6 months. Some studies have also found no
association between duration of illness and surgical outcomes in terms of
eye function. These authors explained that because the patient was elderly,
the disease was prolonged and occurred in one eye, the preoperative visual
acuity was very low, so they may not be able to accurately describe the
course of the disease.
On the other hand, the lesions in scenario were severe, so the recovery
time was different at different follow-up points between studies.
4.3.2.2. Preoperative size of macular hole
The size of the macular hole is related to postoperative visual acuity.
Larger macular holes related to lower postoperative visual acuity. In our