·Clinical Research·
Evaluation
of functional outcome and stability of sutureless scleral tunnel fixated IOLs
in children with ectopia lentis
Anju
Rastogi, Prateek Kumar, Shweta Dhiman, Manisha Mishra, Kamlesh Anand, Ankita
Bhardwaj
Department of Ophthalmology, Guru
Nanak Eye Centre, Maulana Azad Medical College, New Delhi 110002, India
Correspondence to: Shweta Dhiman. 3168/c- 231 Chander
Nagar, Tri Nagar, Delhi 110035, India. dr.shwetadhiman@yahoo.com
Received:
Abstract
AIM: To evaluate functional
outcome of sutureless scleral tunnel intraocular lens (SSTIOL) in children with
crystalline lens subluxation of more than 7 clock hours.
METHODS: A prospective
interventional study was conducted consisting of 45 eyes of 44 children in age
group 6-18y having >7 clock hours of lens subluxation who underwent
lensectomy-vitrectomy followed by SSTIOL implantation. Primary outcome was
improvement in best corrected visual acuity (BCVA) and secondary outcomes were
assessment of intraocular lens (IOL) tilt using ultrasound biomicroscopy (UBM),
mean change in astigmatism at last follow-up of 1y and associated
complications.
RESULTS: The mean preoperative
and postoperative BCVA was 1.05±0.28 and 0.64±0.45 (logMAR) respectively (P=0.001)
at last follow-up. The mean astigmatism preoperatively and postoperatively was
-4.17±2.69 D and -1.86±1.25 D respectively (P=0.011). Significant IOL
tilt (>5 degrees) was present in 5 cases. The mean percentage endothelial
loss was 3.65%±1.92%. The most serious complication encountered was retinal
detachment seen in 2 cases.
CONCLUSION: SSTIOL implantation
provides efficient visual rehabilitation in children provided there is
stringent case selection. We recommend caution in children having
white-to-white distance >
KEYWORDS: ectopia lentis;
subluxated lens; sutureless scleral tunnel fixated intraocular lens
DOI:10.18240/ijo.2020.01.10
Citation:
Rastogi A, Kumar P, Dhiman S, Mishra M, Anand K, Bhardwaj A. Evaluation of
functional outcome and stability of sutureless scleral tunnel fixated IOLs in
children with ectopia lentis. Int J Ophthalmol 2020;13(1):66-70
INTRODUCTION
Lens subluxation in children is a
frequently encountered challenging problem. It can induce significant oblique
astigmatism and high refractive errors which can lead to amblyopia, thereby
hindering early visual rehabilitation.
Management of subluxated lenses
ranges from conservative techniques like optical correction in mild cases to
in-the-bag intraocular lens (IOL) implantation with modified capsular tension
ring (mCTR) in moderate subluxations. In severe lens subluxations, lensectomy
can be done with management of the resultant aphakia. The options available are
anterior chamber IOLs (ACIOLs), iris fixated IOL (anterior and retropupillary)
and scleral fixated IOLs (sutured and sutureless)[1-2].
The modern
day open loop ACIOLs have potential complications of corneal
decompensation, uveitis, glaucoma, hyphaema and peripheral anterior synechiae
in children[3-4].
Sutured
scleral fixated IOLs (SFIOLs) are a popular option. The technique is surgically
demanding and has suture related complications like suture degradation, IOL
dislocations due to suture breakage and endophthalmitis[5-6].
In recent
years, sutureless scleral tunnel IOLs (SSTIOLs) have gained popularity. This
technique eliminates the suture related complications of SFIOLs while
maintaining advantages over ACIOLs. It has shown high success rates in adults
but there is paucity of literature on their functional outcome and safety in
children[7-8]. We evaluated the
stability, functional outcome and complications of SSTIOLs in children between
6-18 years of age.
SUBJECTS AND METHODS
Ethical Approval Approval was taken from the
Institutional Ethics Committee and research adhered to the tenets of the
Declaration of Helsinki. We conducted a prospective interventional study in a
tertiary eye care centre. Totally 45 eyes of 44 children in age group 6-18y
with crystalline lens subluxation >7 clock hours (ectopia lentis) were
enrolled in the study after taking informed consent.
Patients with pre-existing corneal
pathology, uveitis, glaucoma, optic nerve pathology and posterior segment
abnormalities were excluded. A thorough preoperative ophthalmic evaluation was
performed including best corrected visual acuity (BCVA) using Snellen chart,
retinoscopy (wherever possible), endothelial cell count (SP-200P), intraocular
pressure (IOP) measurement (SHIN-NIPPON NCT-10) and dilated posterior segment
assessment. Ultrasound B scan (APPASWAMY MARVELL-II) was done wherever fundus
evaluation could not be performed. All the patients underwent
lensectomy-vitrectomy followed by SSTIOL implantation. Postoperative assessment
was done at 1wk, 1, 3 and 6mo and final outcome was assessed at 1y follow-up.
Ultrasound biomicroscopy (UBM) was used to assess IOL tilt (>5° tilt with
reference to iris plane was considered as significant). Pseudophacodonesis was
evaluated on slit lamp as demonstrated by Möonestam[9]
[after pupillary dilatation, patients were asked to look in upward direction
for 5s followed by quick downgaze to induce IOL movement which was classified
as none (0), minor (1), moderate (2), and severe (3)].
Surgical Technique All surgeries were performed by same
surgeon under general or peribulbar anesthesia. Two limbus based partial
thickness scleral flaps of approximately 3×
Figure 1 Surgical steps of sutureless
scleral tunnel IOL fixation A:
Creation of scleral flaps exactly 180° apart; B: Creation of scleral tunnel
under scleral flaps; C: Lensectomy-vitrectomy being done; D: Leading haptic externalized;
E: Trailing haptic externalized; F: Tucking of haptics in scleral tunnel.
Postoperative Period All patients received a 5-day course
of systemic antibiotics i.e. syrup amoxicillin (250 mg/5mL) 20 mg/kg in
divided doses and capsule amoxicillin 500 mg according to age along with
topical prednisolone 1% eye drops, topical antibiotics and oral steroids (1
mg/kg) tapered for 6wk. Amblyopia therapy was initiated 1mo after the surgery
wherever necessary.
Data Analysis Data was analysed using SPSS version
21.0. Normality of data was tested by Kolmogorov-Smirnov test. If the normality
was rejected then non parametric test was used. Quantitative variables were
compared using Mann-Whitney test/independent t test between the two
groups and Paired t test/Wilcoxon signed rank test was used across
follow up comparison. P value of <0.05 was considered statistically
significant.
RESULTS
Mean age was 10.86±3.26y (6-17y).
Totally 80% cases were males and 20% were females. Marfan’s syndrome accounted
for 85% and Homocystinuria for 15% of all subluxations.
The mean preoperative and
postoperative BCVA was 1.05±0.28 and 0.64±0.45 logMAR respectively at 1y
follow-up (P=0.001) which was statistically significant. Amblyopia was
an important vision limiting factor observed in 18 eyes.
The mean preoperative and
postoperative spherical equivalent was -10.91±4.03 D and -0.42±0.91 D
respectively at 1y follow-up (P<0.001) which was statistically
significant. The mean preoperative and postoperative astigmatism was -4.17±2.69
D and -1.86±1.25 D respectively at 1y follow-up (P=0.013) which was
statistically significant. Table 1 shows comparison of preoperative and
postoperative parameters.
Table 1 Comparison of preoperative
and postoperative (at 1y follow-up) parameters
|
Parameters |
Preoperative |
Postoperative |
P |
||
|
3mo |
6mo |
1y |
|||
|
Mean BCVA (logMAR) |
1.05±0.28 |
0.68±0.43 |
0.64±0.45 |
0.64±0.45 |
0.001 |
|
Mean spherical equivalent (D) |
-10.91±4.03 |
0.41±0.91 |
-0.42±0.91 |
-0.42±0.91 |
<0.001 |
|
Mean astigmatism (D) |
-4.17±2.69 |
-1.87±1.24 |
-1.86±1.25 |
-1.86±1.25 |
0.011 |
|
Mean IOP (mm Hg) |
15.75±2.37 |
14.7±2.63 |
14.8±2.64 |
14.8±2.64 |
0.60 |
|
Mean endothelial count (cells/mm2) |
2882±149.5 |
2778.16±162.5 |
2777.18±159.9 |
2777.17±159.9 |
<0.001 |
BCVA: Best corrected visual acuity;
IOP: Intraocular pressure.
IOL tilt was analyzed using UBM
(Figure 2) and angular tilt >5° in either axis was
considered to be significant. The mean BCVA in eyes with tilt was 1.13±0.49 D
and in eyes without tilt was 0.59±0.45 D. Although the mean BCVA was better in
eyes without significant tilt, this difference was not statistically
significant (P=0.139). The mean astigmatism in eyes with significant
tilt was -2.88±0.18 D and in eyes without significant tilt was -1.71±1.27 D.
Although the mean astigmatism was less in eyes without significant tilt, this
difference was not statistically significant (P=0.23). None of the
patients had clinically evident decentration in a mesopic pupil. In our study,
none of the eyes had significant pseudophacodonesis on slit lamp examination.
Figure 2 IOL tilt assessments using
Imege J on UBM image A: IOL without significant tilt; B:
IOL with significant tilt.
The mean preoperative and
postoperative IOP was 15.75±2.37 and 14.8±
Complications were classified as
intraoperative, early postoperative (≤1mo) and late postoperative (>1mo;
Table 2). In one case during manipulation, one haptic was deformed and broke.
The defective IOL was immediately explanted and replaced with another IOL.
There were no complications like iridodialysis, IOL drop or hyphaema.
Table 2 Intraoperative and postoperative
complications
|
Complications |
No. of eyes |
|
Intraoperative |
|
|
Haptic breakage |
1 |
|
Early postoperative period
(<1mo) |
|
|
Sclerotomy leak |
1 |
|
Late postoperative period
(>1mo) |
|
|
Rhegmatogenous retinal detachment |
2 |
|
Subconjunctival haptic |
3 |
|
Haptic extrusion |
1 |
In early postoperative period,
transient anterior uveitis and transient IOP rise was seen in 5 and 4 eyes
respectively. Early complications included sclerotomy leak which was seen in 1
eye for which the patient was reoperated and the scleral flap was sutured.
There were no cases of corneal edema, hypotony, IOL decentration, IOL
dislocation, vitreous hemorrhage, macular edema and endophthalmitis in early
postoperative period.
Amongst the late complications, the
most serious complication encountered was rhegmatogenous retinal detachment
(RRD) in 2 patients of Marfan’s syndrome. Other late complications included
subconjunctival haptic in 3 eyes and haptic extrusion in 1 eye. The patient
with haptic extrusion was reoperated for haptic repositioning.
DISCUSSION
Management of large (>7 clock
hours) lens subluxations in children continues to be a perplexing problem for
pediatric ophthalmologists. Despite maximum conservative management, Romano et
al[10] reported ametropic amblyopia in 50%
children with ectopia lentis.
Wherever feasible, in-the-bag
placement of IOL with the aid of mCTR remains most acceptable option. The cases
where it is not feasible, lens extraction can be done with management of
resultant aphakia. Over the years, there has been much discussion on the most
acceptable management option for secondary IOL implantation in children that
offers visual rehabilitation with minimal complications.
The flexible open loop ACIOLs are
technically easier to implant but they are not free of complications[3-4]. Iris claw lenses avoid
potential complications of ACIOLs and SFIOLs. However, they may be associated
with spontaneous disenclavation, pigment dispersion, hyphaema and pupil
ovalization[2,11]. SFIOLs is a
time tested option for eyes with inadequate capsular support. Numerous
modifications of this technique have been described. This method is surgically
demanding and involves intra operative manipulation of vitreous base with
potential risk for retinal detachment and suture related complications[5-6].
SSTIOLs popularized by Gabor and
Pavlidis[12] have the advantage of avoiding
complications of ACIOLs. Many studies have shown SSTIOLs to be a simple, safe
and effective technique in adults but there is paucity of literature on use of
this technique in children.
In our study, there was significant
improvement in the mean BCVA, spherical equivalent and a significant reduction
in mean astigmatism was seen with SSTIOL implantation which is comparable to
similar studies[13-15]. In
children with immature visual system, amblyopia is a common obstacle for early
visual rehabilitation. In our study, 18 eyes were amblyopic. We chose foldable
3 piece IOL (Abbot AR40e IOL) for implantation in our study which allowed IOL
implantation with a small incision. In our experience this IOL has sturdy
haptics enabling easier manipulation. Smaller incision provided advantage of
lesser astigmatism, globe stability and less frequent globe collapse.
In addition to visual
rehabilitation, postoperative IOL stability is an important concern in
management of large lens subluxations in children. IOL stability depends on
positioning of scleral flaps exactly 180° apart, equidistant
sclerotomies from the limbus and adequate tucking of haptics in scleral tunnels.
The main stabilizing factor is the fibrosis taking place around the haptic
tucked in scleral tunnels. Tsai and Tseng[16]
demonstrated that IOL tilt >5° can cause significant oblique astigmatism
which is difficult to correct with spectacles. In our study 5 eyes had IOL tilt
>5°. However there was no statistically significant difference between eyes
with and without significant tilt in terms of BCVA and postoperative
astigmatism.
Eyes with pseudophacodonesis, due to
oscillations in fluid in anterior and posterior segment, are prone to develop
endothelial damage and macular edema. Theoretically SSTIOL decrease the risk of
pseudophacodonesis as compared to SFIOLs since stability is provided by an
intrascleral segment of haptic as opposed to point fixation in SFIOLs. In our
study, none of the eyes had pseudophacodonesis on the final follow-up. There
was significant reduction in endothelial cell count postoperatively with mean
percentage cell loss of 3.65%±1.92%. The reason of endothelial cell loss in our
study could be intraoperative manipulation in few cases. None of the eyes
developed corneal decompensation or corneal edema postoperatively. Both
findings correlated well with other studies on glued IOL implantation in
children[7,17-18].
It is difficult to create scleral
tunnel due to low scleral rigidity and lack of counterforce in pediatric eyes
especially after thorough vitrectomy where globe hypotony makes haptic
externalization and intrascleral haptic placement very challenging. In our
opinion, patients with horizontal limbus-limbus diameter >
The fundus examination is of utmost
importance in cases of ectopia lentis as they are predisposed to retinal
detachment. The incidence of retinal detatchment in eyes undergoing SFIOL
implantation has been reported between 0-9.5% in literature[19].
In our study, 2 eyes developed RRD. On retrospective analysis, both patients
were diagnosed cases of Marfan’s syndrome. There were no cases of IOL
dislocation, cystoid macular edema, pseudophacodonesis, IOL dislocation,
vitreous hemorrhage, pigment dispersion and endophthalmitis in our study.
We conclude, SSTIOL implantation
provides efficient visual rehabilitation in children provided there is
stringent case selection. We recommend a thorough preoperative screening and
caution in children having white-to-white distance >
ACKNOWLEDGEMENTS
Conflicts of Interest: Rastogi A, None; Kumar P, None; Dhiman
S, None; Mishra M, None; Anand K, None; Bhardwaj A, None.
REFERENCES