1
INTRODUCTION TO THESIS
1. INTRODUCTION
In patients with inadequate or absence of capsular support, the
implantation of IOL using scleral-fixated technique with the haptic
placed in sulcus, similarly to the natural anatomy of the lens, helps
restore the physiological structure of the eyeball, thus resulting in good
anatomical and functional outcomes. The use of intraocular endoscopy
helps easily approach peripheral structures of the posterior segment
(ciliary sulcus,…) especially in difficult conditions such as small,
irregularly shaped pupil. This allows the surgeon to observe and perform
more accurately, improve the quality of the surgery and provide better
outcomes to patient. Therefore, we conducted this study "Study the
outcomes of scleral fixation of intraocular lens using intraocular
endoscopy" to improve the accuracy of surgery, avoid complications,
thus improving the outcomes of treatment, optimizing vision for patients
with the following objectives:
1. Describe clinical features of eyes without lens and posterior
capsule.
2. Evaluate the outcomes of scleral-fixated intraocular lens
implantation using intraocular endoscopy
3. Analysis of factors related to the outcomes of surgery.
2. NOVEL FINDINGS:
- This is the first study to evaluate the overall results of scleral-fixated
intraocular lens implantation using intraocular endoscopy in Vietnam.
- Additional research, provide better understanding of clinical features
and causes of aphakia and damage of posterior capsule.
- Study the application of new tool in ophthalmology: intraocular
endoscopy in scleral-fixated IOL implantation to help increase success
rate, reduce complications.
- The scleral fixated technique of cover the suture inside the sclera
helps reduce the incidence of postoperative complication: suture erosion,
with the use of the suture 10/0 poly propylene which is very common and
can be used at lower level hospitals.
3. OUTLINE: The dissertation consists of 131 pages, including 4
chapters. Introduction (2 pages); Chapter 2: Objectives and Methods (17
pages), Chapter 3: Results (39 pages), Chapter 4: Discussion (32 pages),
Conclusions and Recommended (3 pages).
- There are also references, annexes, tables, charts, pictures
illustrating the results of the treatment.
2
CHAPTER 1
LITERATURE REVIEW
1. The use of intraocular endoscopy in ophthalmology
Intraocular endoscopy is used in ophthalmology for 2 reasons: first,
this device allows surgeon to observe the posterior segment even when
there’s an opaque in the visual axis which obscures the view as corneal
scar, hyphema, small pupil, cataract or subcapsular cataract. Second,
intraocular endoscopy can help visualize intraocular structures that other
devices fail to produce, such as behind the iris, sulcus, ciliary body, the
pars plana and the peripheral retina.
Indication of using intraocular endoscopy:
- Diseases which required intervention but in associated with other
diseases that obstruct the observation with a non-contact microscope:
+ Corneal edema, corneal opaque
+ Damages of cornea, ICE, hyphema.
+ Eyes with previous surgery such as iris fixation IOL
+ Cataract, sub-capsular cataract induced by corticosteroid.
+ Surgical abnormalities: gas in anterior chamber, subluxation IOL,
subluxation lens.
- Ophthalmic diseases:
+ Retinal Detachment with retinal tear in peripheral
+ Trauma
+ Endophthalmitis
+ Scleral rupture with vitreous rent.
+ Small cornea
+ Aphakia, subluxation IOL
+ Refractory glaucoma
2. Scleral fixation of intraocular lens
In 2003, the American Society of Ophthalmology reviewed the
methods of placing intraocular lens in patients without capsular support
and concludes that sclera fixation of intraocular lens is a safe and
effective method.
* Choose the type of intraocular lens:
- The total intraocular lens diameter must be from 12.5 to 13mm
3
- Optical diameter of the intraocular lens must be 6mm or wider
- Intraocular lens: The angle between the optical part and haptic part
is about 10 degrees, type of intraocular lens which are commonly used:
Alcon CZ70BD (Alcon, Fort Worth, Texas), Bausch and Lomb 6190B
(Bausch and Lomb, San Dimas, California).
* Calculate the power of the intraocular lens: Formula for intraocular
lens power calculation
The constants used for the SRK formula relate to many factors such
as the location of the intraocular lens, the technique to be used, the
choice of the intraocular lens type. This formula (P = A-2.5L-0.9K) has a
known A value for each type of intraocular lens so it is easy to use. When
intraocular lens is placed in the ciliary sulcus, the reduction of intraocular
lens power to 0.5 D is recommended by the authors.
* Suture using in sclera fixation of intraocular lens: The only fixed
material used is polypropylene material due to long time stability in the
eyeball. Depending on the technique selected each author uses the needle
with different shape like straight needles, curved needles but still the
same polypropylene material.
* Sclera fixation of intraocular lens: Before sclera fixation of
intraocular lens, vitrectomy should be performed to prevent contraction,
the vitreous should be cleaned around the region of ciliary sulcus where
the needle will go through. Sclera fixation of intraocular lens is carried
out through the following main steps:
+ Position selection for suture fixation: the position chosen depends
on the number of fixed positions needed, but often symmetric, and often
avoid the meridian 3-9h due to the large ring of the cornea, easily lead to
hemorrhage.
+ Suture will be fixed at 0.75 to 1mm from the limbus
+ Tie the suture to the haptic of IOL, insert IOL into anterior
chamber.
+ Suture the haptic into the sclera..
* Suture knot burried methods used for sclera fixation of intraocular
lens:
+ Leave the suture knot on the sclera surface
+ Cover the suture knot by artificial corneal flap
+ Cover the suture knot by the flap of Fascia lata or Dura mater
+ Cover by the scleral flap
+ Create the continuous suture knot, rotate the suture inside
4
+ Create the grooves near the limbus, put the suture knot at 2 or 4
position
+ Burried the suture knot in the sclera tunnel
+ Cover the suture knot by Z shape
* Needle passing technique:
+ Technique to place the needle passed from the internal to the
external of the eyeballs: This technique less distorts the eyeballs, but
because the passing area is obscured, therefore, the needle can to pierce
into the ciliary body, ciliary processes causing intraocular hemorrhage.
+ External needle-passing needle technique was first described by
Lewis (1991). The advantage of this method is to accurately locate the
position for the needle to pass, so the ability to place accurately into the
ciliary sulcus is very high.
* Techniques to tie the suture into the haptic of intraocular lens
+Technique for tying a noose: is usually applied in cases where the
intraocular lens without holes on the haptic, the surgeon usually use
suegical instrument to clamp the haptic of intraocular lens to be flattened
head, the noose will not slip.
+ Technique of putting the loop suture through the holes on the haptic
of the intraocular lens: The piercing method is only fixed through the
holes on the haptic of intraocular lens to force the knot to be made only
according to the twisting technique and to create a continuous noose loop
Picture 1.1. Technique of putting the loop suture through the holes
on the haptic of IOL
* Scleral-fixated of intraocular lens using intraocular endoscopy
Using intraocular endoscopy allows the surgeon to observe the
unobserved areas behind the iris of the eyeball, especially the ciliary
sulcus. The endoscope allows the surgeon to know exactly the right
position of intraocular lens and at the same time to control the
complications that can occur during surgery such as bleeding,
5
Picture 1.2. Suture goes through 30G needle and endoscopy inserted
into the eyeball
Picture 1.3. Steps of cover the knot into the scleral
* Complications of posterior chamber IOLs in aphakic patients.
+ Cystoid macular edema
+ Endophthalmitis
+ Vitreal hemorraghe
+ Subluxation IOL
+ retinal detachment
+ Choroidal hemorrhage
+ Suture erosion
CHAPTER 2
SUBJECT AND STUDY METHOD
2.1.Subjects:
The study was conducted at the Trauma Department of Vietnam national
institute of Ophthalmology from December 2010 to December 2015.
2.1.1.Inclusion criteria:
Patients over 5 years of age with history of intracapsulcar cataract
extraction, aphakia or damages to posterior capsular due to different
causes, who undergone examination and treatment at the Trauma
Department, have best visual acuity increasing with Snellen chart.
2.1.2. Exclusion criteria: Patients with acute eye diseases such as
conjunctivitis, dacryocystitis, abnormal coagulation, phthisis bulbi,
abnormal macular, optic disc atrophy, retinal detachment, heart disease,
system diseases, diabetes.
6
2.2. Research methods
2.2.1. Study design: This is a prospective study, clinical trial, vertical
follow up, no control group. Patients were monitored from hospital
admission, hospital discharge and 1 month, 3 months, 6 months, 1 year
after discharged. The data were collected according to the individual case
study form.
2.2.2. Sample size: The sample size is determined by the formula
From the formula we can calculate the sample size in the study: n =
92 eyes. We selected 103 eyes of patients with eligible criteria for
inclusion in the study, a follow-up period of at least 12 months.
2.2.3. Protocol
2.2.3.1. Preoperative clinical manifestations:
a) History taking
+ Age, gender, occupation, address and telephone number of the
patient. History of the disease: chief complain. Systemic diseases.
Previous surgery, when, where? How long does it take, what happens
after previous treatments? (refer to old medical records if available).
Ophthalmic examination:
* Functional exams: Vision acuity, best corrected vision acuity to
prognosis postoperative visual acuity, using Snellen chart. Measure IOP
using Maclakop tonometer.
* Examination: cornea, iris, pupil, iris, tear, degeneration, iris
coloboma, anterior chamber. Ophthalmoscopy to evaluate the posterior
segment. Functional tests.
2.2.3.2. Surgical techniques in this research :
Insert a 23G trocar at pars plana, 3,5 mm from the limbus at the
meridian of 8h30 in the right eye and at the meridian of 4h30 with the
left eye to keep the eye pressure stable during surgery. Open conjunctival
at meridians 2h and 8h or 4h and 10h.
+ Make a deep grooves of ½ thickness of sclera (using 15 degree
knife), usually perpendicular and 1 mm to the limbus, two symmetrically
180 degrees at the opening of the conjunctiva. Cut the superior of the
cornea with 3mm length into the anterior chamber, cut the remaining
vitreous (if any), inject viscoat into anterior chamber to protect corneal
endothelium.
7
+ Put 10/0 polypropylene through 30G needle, suture 10/0
polypropylene is cut in the middle, threaded each end without the needle
of the thread cut into the 30G needle from the tip of the needle towards
the head needle (drawing).
Picture 2.1. Put the polypropylene suture through the 30G needle
Using the endoscope to see the ciliary sulcus, the endoscope goes into
the eyeball through the corneal incision on the edge of the upper. The
surgeon moves the endoscope into the ciliary processes area
corresponding to the scleral groove, while the other hand inserted 10/0
suture from the outside into the eyeball through the incision 1mm from
limbus. Observe under the intraocular endoscopy, the needle is inserted
into the eyeball, the surgeon can adjust the needle to insert accurately to
the right position. Withdraw endoscopy from the eyeball, use hook to
pull the suture outward through the upper corneal incision, the surgeon
repeats the procedure to the opposite side.
+ Tie the suture to IOL using continuous knot (Figure). Pull the straps
through the hole of IOL CZ70BD, draw up and round through the tip of
the IOL, then pull the suture to fixed IOL, the straps will be tied strongly
into the IOL.
Picture 2.2. Suture loop fixed on the haptic
+ Corneal incision, insert IOL into posterior chamber. Fixated IOL
into the scleral using continuous loop, cover the knot into the scleral.
+ Close conjunctive. Close corneal incision by 1 or 2 poly propylene
10/0 suture.
+ Note all details into surgical notes.
2.2.4. Study Variables and Indicators
* Preoperative clinical manifestations: Age distribution, sex,
occupation, causes and time since the damages of posterior capsule, type,
8
number of previous surgeries, Visual acuity without glasses and the best
corrected vision acuity before surgery. Characteristics of IOP, refraction
of patients before surgery. Eye injuries before surgery: cornea, iris,
vitreo, retina.
*Study indicators relating to Outcomes
+Post – operative best corrected visual acuity (BCVA): The best
assessment of vision changes after surgery: Vision changes are evaluated
by increasing, decreasing, or unchange visual acuity compared to before
surgery.
Visual Acuity increased
• VA ≥ 20/200: increase at least one row in the Snellen chart
• VA from FC 1m to 20/200: vision increased from 20/400 or above
• VA <1m: Any increase in vision is considered as improvement
Visual acuity: no change between before and after treatment
VA reduced:
• VA ≥ 20/200: reduce at least one row in Snellen chart
• VA <20/200: any reduction in vision.
+ Intraocular lens
- Assessment of the status and position of the IOL, haptic of IOL
through ultrasound biomicroscopy of anterior chamber angle assessment
mode at the meridians of fixated suture.
- Assessment of IOL balance: Take the intersection between the two
meridians cut through the sclera position of 90 degrees and 180 degrees:
a) IOL balance: If IOL center deviated from the intersection between
two meridians on the <1mm.
b) IOL slightly deviated: If IOL center deviated from the intersection
between two meridians 1-2mm.
c) IOL deviation medium: If IOL center deviated from the midpoint 2
meridians 2 - 3 mm.
d) IOL deviation severely: If IOL center deviated from the
intersection between 2 meridians over 3 mm. - Assessment of IOL tilt: If
the IOL tilted over the horizontal of the sclera over 3 degrees.
- Assessment of factors affecting the balance of IOL after surgery.
+ Evaluation of the position of the knot fixed IOL on the sclera:
- Good: the knot is only marked good when the head is only fully
covered in the groove of the sclera, conjunctiva covers the knot
completely.
9
- Average: the knot is covered completely in the groove of the sclera,
leaving the bridge of the suture loose in the conjunctiva.
- Bad: The knot is completely located outside the groove of the sclera.
+ Evaluate complications
- Intraopeartive complication: vitreal hemorrhage, choroidal
detachment, corneal incision open, hyphema, inflammation,
endophthalmitis, increase IOP.
- Late complications: Complications related to knot, uveitis,
glaucoma.
+ Evaluation of outcomes of surgery
- Good: IOP balance, no complications during and after surgery.
Power is equal to or higher than the maximal preoperative best corrected
visual acuity.
- Moderate: IOL balance or slight deviation, loose suture bridges
under the conjunctiva, increased VA.
- Failure: IOL deviation moderate or severe, suture erosion,
complications during or after surgery. VA does not increase or decrease.
+ Evaluation of relating factors affecting the outcome of the surgery
- Factors related to visual acuity after surgery.
- Factors related to postoperative anatomical outcomes.
- Factors related to complications during and after surgery.
2.3. Đata processing
Data processing: Data are collected and processed according to
medical statistical calculations, SPSS 16.0 software.
2.4. Ethical in medical studies: Study of compliance with ethical norms
in the biomedical research of the Ministry of Health and approved by the
ethical board of ethics.
CHAPTER 3
RESULTS
3.1. Clinical manifestations of preoperative patients with iol fixation
3.1.1. Demographic data
The study was conducted on 94 patients with 103 eyes. We analyze
the general characteristics of the research team.
3.1.1.1. Age group
Patients who is aphakia were mainly in working age, distributed fairly
equally in 3 age groups aged 15-30 years, 30-45 years old, 45-60 years
old (23.4-27.7% with p> 0, 05). Children and the elderly who is aphakia
accounted for a lower proportion (14.9% and 10.6%).
10
3.1.1.2. Gender
Of the 94 patients, the majority of the patients were male, accounting
for 79.8% (p <0.0001). The majority of patients lived in rural areas
(85.1%), only 14 out of 94 patients lived in city.
3.1.1.4. Occupation
Of the 94 patients, the majority of farmers and workers (62.8%), patients
are students and intellectuals account for a lower proportion (16-20.2%). Eye
disease The study was conducted on 94 patients, 103 eyes were aphakia, of
which 47.6% is right eye (49 eyes), left eye accounted for 52.4% (54 eyes)
no difference between right eye and left eye (p> 0.05).
3.1.1.5. Causes of posterior capsule and aphakia
The main cause of the damages to lens is trauma (80.6%), of which blunt
ocular trauma occurred in 35.9% and penetrating trauma was 44.7%. Next
common causes are congenital abmornal of lens, accounting for 16.5%.
3.1.1.6. Timing of posterior capsule and lens loss
Most of the eyes have time after posterior capsule and lens loss from
1-3 months, accounting for 56.3% (p <0.01). The time between the lost
and IOL implantation was varied, ranging from 1 to 240 months.
3.1.1.7. Number of previous surgeries
The majority of eyes in the study were operated 1 time, accounted for
86.4% (89 eyes), the remaining eye was operated 2 times or more, 2
times 9.7% (10 eyes), over 3 times 3.9 % ( 4 eyes).
3.1.1.7. Previous surgery.
The majority of eyes in the study had undergone vitrectomy and
lensectomy (41.7%). 31/93 eyes undergone sclera-cornea suture,
vitrectomy and lens extraction accounting for 30.1%. The number of eyes
undergone vitrectomy with gas or silicone oil tamponade due to retinal
detachment was 8/103 (7.8%). Other surgical procedures such as
vitrectomy associated with lens extraction and foreign body removal in
trauma eyes, vitrectomy in endophthalmitis + lesectomy with or without
oil, oil removal account for a small proportion(6.8%).
3.1.2. Functional characteristics
3.1.2.1. Preoperative visual acuity
Prior to surgery, the majority of UCVA is 20/400 (82.5%). After best
corrected, preop VA significantly improved, only 4,9% of eyes have poor
VA (less than 20/400), up to 47,6% of eyes have VA better than 20/200.
11
50
45
40
35
30
25
20
15
10
5
0
< CF 1m
%
CF 1m - <20/400
20/400 - 20/200
> 20/200 - 20/70
20/60 - 20/30
43.7
38.8
49.5
31.1
15.5
14.6
1.9 0
Uncorrected VA
1
3.9
Corrected VA
Chart 3.1: Pre-operative VA
3.1.2.2. Preoperative astigmatism
Only 96/103 eyes were refracted before surgery so the preoperative
astigmatism was analyzed on 96 eyes.
Average preoperative astigmatism: 1.13 ± 1.11 (min: 0; max: 6.25). The
majority of eyes had astigmatism below 1 Diop, accounting for 45.6%.
3.1.2.3. Preoperative intraocular pressure
Most eyes have intraocular pressure within the normal range, with
95.8% of eyes under 21mmHg (98 eyes). The mean preoperative
intraocular pressure is 17.6 ± 2.45 mmHg (min: 14 mmHg max: 32
mmHg). Only 3 eyes have intraocular pressure> 25 mmHg (2.9%).
3.1.2.4. Preoperative anatomical features
The eyes in the study group were associated with cornea scar (52.3%);
13.6% of the eyes with sclera stitched; iris trauma 59.2%, abnormal
pupils 60.2%. The number of eyes with different types of retinal lesions
was 36.9%.
3.2. Surgical outcomes
3.2.1. Visual acuity
3.2.1.1. Uncorrected visual acuity
At the time of the new hospital, the number of eyes with un-corrected
vision less than 20/400 accounted for 18/103 eyes (17.5%). After 1
month of surgery, no eye has VA less than 20/400, while the number of
12
eyes have good vision (>20/60) increase from 9,75 to 24,3%. The
difference was statistically significant with p <0.0001.
60
< CF 1m
%
CF 1m <20/400
47.6
20/400 - 20/200
50
40
25.2
30
20
52.4
6.8
10.7
24.3
23.3
9.7
10
0
Post - op
1 month post - op
Chart 3.2. UCVA 1 month post-op
3.2.1.2. Best corrected visual acuity
Table 3.1. The best corrected visual accuity at different time point
Time point
BCVA
20/200 20/70
20/60 20/30
>=20/25
Total
Pre -op
Số
lượn
%
g
1
1,0
4
3,9
51
49,5
32
31,1
15
14,6
103
100,
0
Discharge
Số
lượn
%
g
3
2,9
1month
Số
lượn
%
g
3 months
Số
lượn
%
g
6 months
Số
lượn
%
g
12 months
Số
lượn
%
g
6
5,8
30
29,1
17
16,6
16
15,5
15
14,5
16
15,5
35
34,0
43
41,7
37
35,9
24
23,3
17
16,5
28
27,2
43
41,7
49
47,6
63
61,2
69
67,0
1
1,0
100,
0
1
1,0
100,
0
1
1,0
100,
0
1
1,0
100,
0
103
103
100,
0
103
103
103
At the time of discharge, 28,2% of the eyes had BCVA better than
20/60, 1 month after surgery the propotion increased to 41,7%,
significantly higher . This index continued to increase significantly in the
third month (48,6%) - p <0.005, then remained stable at the later time
(6 months: 62.2%, 12 months : 68%), p <0.0001.
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Similarly, logMAR visual acuity at the time of initial discharge was
similar to the preoperative BCVA (p> 0.05). However, from the first
month after the surgery onward, visual acuity improved significantly
(p <0.001), reached the stability from the third month and continued to
improve in the following months (p> 0.05).
Table 3.2. LogMART BCVA at different time point
Time point
Mean BCVA logMAR
(Min; max)
0.94±0.33(1.8 - 0.2)
0.85±0.42 (1.9 - 0.2)
Pre - op
Pihole
VA
at
discharge
1 month post - op
0.63±0.29 (1.3 - 0.2)
3 month post - op
0.59±0.29 (1.3 - 0.1)
6 month post - op
0.56±0.31 (1.3 - 0.1)
12 month post - op
0.56±0.31 (1.3 - 0.1)
3.2.1.3. Post – operative residual refraction
Of the 96 eyes that were refracted, astigmatism varied greatly. Eyes
with astigmatism ≤ 1 Diop dominate. Prior to surgery, 65.6% of the eyes
have astigmatism ≤ 1 Diop, 18.8% of the eye has astigmatism ranging
from 1-2 Diop. After one month of surgery, astigmatism was generally
increased, the number of astigmatism eyes ≤ 1 diop decreased to 47.9%,
while the number of astigmatism from 1 to 2 diop increased to 28.1% ,
the number of astigmatism higher than 2 diopters also increased
compared to the corresponding figures before surgery (p <0.05).
However, from the third month onwards, the refractometric indexes
returned to near preoperative scores (p> 0.05).
3.2.1.4. Visual acuity of the last visit compared to preoperative best
corrected visual acuity
Chart 3.3. VA at the last follow –up
3.2.3. Anatomical outcomes
14
3.2.3.1. Clinical examination of intraocular lens
The calcification status of IOL is evaluated clinically at all follow-up
points after surgery. Proportion of IOL balance at clinical examination is
quite stable at times (p> 0.05).
3.2.3.2. Intraocular lens in ultrasound biomicroscopy
The mean IOL deviation of 103 eyes is 0.37 ± 1.48mm. In this group,
the group of deviated IOL deviate in difference level and the average
deviation after 6 months was 2.14 mm. Eyes with IOL tilted on the UBM
have a value of 9o. The average IOL deviation of the study group was
0.88 ± 3.4 degrees.
3.2.3.2. Scleral fixation suture knots
Overall, the suture covered rate is very good (96.1 - 99%). After 1
month, there was only one eye (1%) and after 12 months only 3/103 eyes
(2.9%). Loose suture bridge occurs only at very low rate, only in one eye
from 3 months onwards (1%).
3.2.4. Corneal endothelium cell density
There are 55 eyes in the study that can counted the number of
endothelial cells. Of these, 53 eyes had an endothelial cell count of 2,000
cell / mm 2 at both preoperative and post-operative times. Number of
eyes with endothelial cell density> 2500 decreased from 45.5% (prior to
surgery) to 41.8% (6 months after surgery), however, differences in
endothelial cell density before and after surgery was not statistically
significant (p> 0.05).
3.2.5. General surgical outcomes
After 12 months, of the 103 eyes being operated, 3 eyes were
considered to be failures despite increased vision after surgery, however,
the suture did not appeared on the conjunctiva so no further treatment is
needed. The success rate in our study was 94.18%. Difference with
success and failure group was statistically significant with p <0.005.
Table 3.3: Surgical outcomes
Surgical outcomes
Number of eyes
%
Good
97
94,18%
Moderate
3
2,91%
Failure
3
2,91%
Total
103
100,0
3.3. Complications
The only complication of the procedure was bleeding, which occurred
in 8 out of 10 eyes (7.8%). All eyes with complications have vitreous
15
hemorraghe, then self-limited.
3.3.2. Complications after surgery
The incidence of early postoperative complications was 10%,
decreasing later at times of follow-up. Early complications include
vitreous hemorrhage, choroidal detachment, IOP incresed, suture erosion
in the first month after surgery.
3.4. Predictive factors
3.4.1. Pre – and Post – operative association between corneal damage
and astigmatism
At all times, corneal damage has an effect on the refractive index of
the cylinder. The central corneal lesions exhibited astigmatism before
and after surgery more than normal corneal cornea and peripheral corneal
lesions. The difference was statistically significant with p <0.0001.
3.4.2. Predictive factors of post – operative best corrected visual
acuity
3.4.2.1. Causes of lens loss
The BCVA of groups with difference cause of lens loss was not
statistically significant at the time of follow-up. The BCVA at different
time point post-op of the two trauma groups: blunt trauma and
penetrating trauma were not significantly different at baseline and after 1
month (p> 0.05). However, from 3 months onwards, BCVA in the blunt
trauma group was significantly higher (p <0.05).
3.4.2.2. Timing of lens loss
The duration of lens loss did not affect postoperative BCVA
(p> 0.05). Patients with lens and posterior capsule loss over 12 months
were mainly those who undergone intracapsular cataract extraction as
treatment of congenital abnormalities of lens.
3.4.2.3. Number of previous surgeries
Previous surgery had no effect on postoperative vision at any time
point (p> 0.05). BCVA in group undergone vitrectomay ans lensectomy
with or without cornea scleral suture is significantly higher than the
group who was underone surgery for retinal detachment,
endophthalmitis, foreign body and lens removal. VA difference in both
groups was statistically significant at all postoperative follow-up
(p <0.001)
3.4.2.4. Association between previous ocular damages and post –
operative best corrected visual acuity
a) Cornea
16
Subjects with central corneal scars had VA worse than those with
normal corneal or peripheral corneal scars at all time of observation with
p <0.005. BCVA in group with central corneal scar significantly worse
than the other two groups with p <0.001 at all monitoring points.
b) Iris
The iris trauma group had VA worse than the normal iris group
(p <0.001) at all follow-up points after surgery.
c) Pupil
Irregular pupil significantly reduced visual acuity compared to normal
and dilated pupils at postoperative follow-up (p <0.05).
d) Retina
Retinal damage is one of the factors that reduce vision after surgery.
The group with retina damage has the lowest VA after surgery was
compared with the other two groups (p <0.005).
3.4.2.5. Predictive factors of best corrected visual acuity at the last visit
Corneal damage significantly affects postoperative VA (p <0.0001),
retinal status is also an important factor affecting visual acuity (p = 0.11),
type of surgery Previously, it also affected the postoperative BCVA
(p = 0.14). Geography is also one of the factors related to postoperative
VA (p = 0.026).
Table 3.4: Factors relating to BCVA 12 months post-op
Factors
p
(Constant)
0,943
Cornea status pre-op
0,000
Iris pre-op
0,447
Pupil pre-op
0,408
Vitreous pre-op
0,539
Retina pre-op
0,011
Previous surgery
0,014
Age
0,329
Gender
0,594
Address
0,026
Occupation
0,639
3.4.3. Predictive factors of anatomical outcomes
3.4.3.1. Types of previous surgeries
We divided the two surgical groups: vitrestomy and lensectomy with
or without cornea scleral suture; vitrectomy and lensectomy in treatment
of retinal detachment, endophthalmitis and intraocular foreign body. The
IOL status in the two surgical groups was not significantly different at
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the time of cfollow-up (p> 0.05).
3.4.3.2. Corneal damage
The group with central corneal scars had a signifiantly lower
incidence of IOL deviation than those in the rest (clear corneal and
corneal scar in periphery), with p <= .05 at the following surgery. At the
two check-up time for IOL location by UBM in the first and sixth months
post-op, we found that the group with central corneal injury had an effect
on IOL balance on UBM (p <0.05).
3.4.3.3. Causes of lens loss
We divide the cause of lens loss into two groups, one is penetrating
trauma and other is all the remaining cause. Group with lens loss due to
penetrating trauma has a significantly higher incidence of IOL tilted than
other causes with p <0.05.
3.4.4. Predictive factors of complications
Previous surgery did not affect the occurrence of surgical
complications (p = 0.506). Postoperative complications in the group
which has one previous surgery or group with 2 or more surgeries had no
significant different. Previously performed surgery did not affect the rate
of complications encountered in IOL fixation (p> 0.05).
CHAPTER 4
DISCUSSION
4.1. Clinical manifestations of preoperative patients with scleral fixation
of intraocular len
4.1.1. Characteristics of population study
The study group consisted of 94 patients, in which men accounted for
the majority (75%), with 79% (79%). In addition, 85.1% of the patients
live in rural areas, 62.8% of them are farmers or workers. The median
duration of the study was 21.9 months. Most of the eyes, IOL were
implemented within 2 months after surgery (56.3%), after 12 months
only account for 20.4% of the eyes, this group almost all patient with
congenital cataract has been removed. The majority of patients in this
study had 1 previous surgery (86.4%), only 10 eyes had 2 surgeries and 4
eyes had more than 2 surgeries. Most of the eyes undergone vitrectomy
and lensectomy accounted for 41.7%. In eyes with penetrating trauma,
the cornea suture may be combined in the same surgery (30.1%). There
were 14 out of 103 eyes who undergone ICCE , mainly in children with
congenital cataract.
4.1.2. Preoperative clinical manifestations
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4.1.2.1. Visual acuity
Prior to surgery, the majority of UCVA less than 20/400 (82.5%). After
refraction, BCVA pre-op significantly improved, only 4,9% of eyes with
poor VA (less than 20/400), up to 14,6% of eyes have VA over 20/60.
Similar logMAR preoperative vision before and after maximal correction
has significantly changed, decreasing from 1.73 to 0.94, (p <0.0001).
4.1.2.2. Corneal astigmatism
The preoperative astigmatism score was 1.13 Diop, the lowest was 0
Diop, the highest was 6.25 Diop. 45.6% of the eyes in the study group
had astigmatism under 1 Diop, 28.2% had astigmatism from 2 to 3 Diop.
Index of astigmatism outside of refraction with astigmatism is also very
relevant to the corneal status of the patient. 55.3% of the eyes have
corneal lesions, of which 25.2% have previous corneal lesions in the
center, thus also causing or increasing the degree of astigmatism
available to the patient.
4.1.2.3. Anatomical features
Because study subjects included aphakic eyes, experienced previous
traumas and previous surgery, these eyes are no longer complete,
possibly with different lesions. Specifically, 13.6% of the eyes had scars
due to ruptured, 59.2% of the eyes had iris damage, including various
lesions such as fibrosis, adhesions, rupture of the iris root, iris loss of one
part or total ... the iris injury will lead to pupil abnormalities such as
distorted pupils (40.8%), pupils dilated over 5mm (19.8%). There were
46.9% of the eyes with different retinal lesions, of which 10.7% had
posterior pole retinal lesions, 26.2% had other lesions, and one had
retinal detachment. 86.4% of the eyes had clear vitreous, the remaining
has a vitreous floaters level 1,2 (1.2.6%).
4.1.2.4. Intraocular pressure
Most eyeballs have intraocular pressure within the normal range
before surgery with an average intraocular pressure of 17.6 mmHg. Only
5 eyes have intraocular pressure> 22 mmHg (4.8%). Only in case of
damage to the trabecular meshwork or ciliary body, affecting the fluid
pathway lead to increase of intraocular pressure.
4.2. Surgical outcomes
4.2.1.Visual acuity
4.2.1.1. Uncorrected visual acuity
After a month, this number has improved significantly. No eyes has
VA less then 20/400. 76,7% of eyes have VA better than 20/200,
19
notably 24,3% eyes have VA better than 20/60. The reason for this
apparent change in vision is that at the time of discharge, vision is
affected by a number of confounding factors, such as corneal edema,
inflammation in the postoperative period (6.8%). , the patient also
feeling irritation, discomfort, eyes are dazzling feeling due to
unfamiliar IOL, this symptom is especially clear in patients with
abnormal pupils, causing vision loss phenomenon temporary. After a
month of surgery, eyeballs have almost completely stabilized, the
cornea is clear, the transient inflammatory reaction after surgery is
stable. IOL stabilized in the posterior chamber, achieving optical
compatibility with other components of the eyeball, resulting in
improved visual acuity (p <0.0001).
4.2.1.2. Best corrected visual acuity
The general visual acuity results show that 92.3% of the eyes have
visual acuity increased compared to the pre-op BCVA. Among those
eyes that do not increase or increase slightly, the cause is mainly caused
by central corneal scars, posterior retina damage and amblyopia.
4.2.1.3. Residual refraction
The median preoperative mean was 1.13 Diop, after one month of
surgery increased to 1.6 Diop (p <0.05). From the third month after
surgery, the astigmatism decreased closer to preoperative and remained
stable over time (p> 0.05). Causes of corneal astigmatism change at
different times after surgery is due to the corneal incision in the surgery
to insert IOL into the anterior chamber. The incision size is 6mm, with
such a large size increasing the incidence of corneal abnormalities.
Incorporation of existing corneal dystrophy of patients due to trauma or
surgery.
4.2.2. Intraocular pressure
In this study, glaucoma was more common than other complications
but with a small incidence (5 eyes - 4.8%), and is often the result of
traumatic injuries or previous surgery.
4.2.3. Anatomical outcomes
4.2.3.1. Clinical examination of intraocular lens
One of the success criteria of surgery is the IOL balance. At the time
of initial discharge, 92.2% of eyes were assessed IOL balance, eight eyes
with IOL deviation at different levels, accounting for 7.8%. From 1
month onwards, the number of IOL tilted eyes does not change, but from
the third month, one eye has tilted IOL. In the tiled IOL group, there are
5 eyes that IOL were tiled on purpose. In these eyes, we actively perform
20
surgery so that the center of the IOL is located behind the clear cornea, in
fact, in these cases, if there is no combined retinal damage, VA
significant improvement. The VA of eye with tiled IOL at moderate and
severe level is from 20/400 post-op; 20/100 to 20/60 (4 eyes).
From the third month onwards, one eye appears tilted, which
corresponds to the appearance of a loose suture bridge on the
conjunctiva. However, the visual acuity of this case decreased due to
astigmatism, from 20/100 to 20/200, the eyes still stable so no need
intervention.
4.2.3.2. Intraocular lens evaluation on ultrasound biomicroscopy
On UBM, IOL was evaluated as balance when the haptic located in
the ciliary processes, the center of IOL deviation from the axis of the
cornea below 1mm. However, in our study, corneal lesions accounted for
52.3% with 25.2% of the eyes with central corneal lesions so we can not
use center cornea as the mark to evaluate the balance of IOL. IOL tilt or
deviation can cause astigmatism, aberrations, patients may have the
feeling of glare. In a patient with previous astigmatism, tilt or deviation
of IOL may increase or decrease total astigmatism. Our study had an
average IOL deviation of 103 eyes of 0.37 mm. In the group with IOL
deviation, the average deviation after 6 months was 2.14 mm. The eyes
with IOL tilted on UBM have a value of 9 °. The average IOL tilt of the
study group was 0.88 °. The results of this study are lower than most
other authors. Our study recorded the number of eyes with IOL deviation
quite stable after 6 months of surgery. At 1 month after surgery, the eyes
are not completely stable, the process of scars of the sclera, cornea is still
going on. But from the 3rd month onwards, the eyeball is completely
stable, IOL is fixed in the groove, there is no displacement, contraction,
the suture knot also achieved stability in the position. Therefore, the
results after the third month onwards have some changes. The number of
eyes with slight IOL tilted increased to 6 eyes (compared with the
previous 5 eyes), one eye was recorded with IOL tilted on UBM due to
the loosen of suture knot. One factor that may affect the IOL deviation is
the late degradation of suture. In this study we used only 10/0
polypropylene, although some previous reports recommend using only
9/0 polypropylene or 8/0 GoreTex. However, two other types are not
available, if the study has longer follow-up time, more IOL tilted can be
detected.
4.2.3.3. Scleral fixation suture knots
Our study showed that the incidence rates in our study were very low,
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