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Long-term outcomes of wedge
resection at the limbus for
high irregular corneal astigmatism after repaired corneal laceration
Jun Du1,
Guang-Ying Zheng1, Cheng-Lin Wen2, Xiao-Fang Zhang1,
Yu Zhu1
1Department of Ophthalmology, the First Affiliated Hospital
of Zhengzhou University, Zhengzhou 450052, Henan Province, China
2Department of Ophthalmology, People’s Hospital of Zhengzhou,
Zhengzhou 450053, Henan Province, China
Correspondence
to: Guang-Ying Zheng. Department of
Ophthalmology, the First Affiliated Hospital of Zhengzhou University, Jianshe East Road No. 1, Zhengzhou
450052, Henan
Province, China. zzzgy@zzu.edu.cn
Received: 2016-05-03
Accepted: 2016-05-24
Abstract
AIM: To evaluate the clinical value of wedge resection at
corneal limbus in patients with traumatic corneal scarring and high irregular
astigmatism.
METHODS: Patients
with traumatic corneal astigmatism
received wedge resection at least 6mo after suture removal from corneal wound.
The uncorrected distance
visual acuities (UCVA) and best corrected distance visual acuities (BCVA), pre- and post-operation
astigmatism, spherical equivalent (SE), safety and complications were
evaluated.
RESULTS: Ten eyes (10 patients) were enrolled in this study. Mean
follow-up time after wedge resection was 37.8±15.4mo (range, 20-61mo). The mean
UCVA improved from +1.07±0.55 logMAR to +0.43±0.22 logMAR (P=0.000) and
the mean BCVA from +0.50±0.30 logMAR to +0.15±0.17 logMAR (P=0.000). The mean astigmatism power measured by retinoscopy was
-2.03±2.27 D postoperatively and -2.83±4.52 D preoperatively (P=0.310).
The mean SE was -0.74±1.61 D postoperatively and -0.64±1.89 D preoperatively (P=0.601).
Two cases developed mild pannus near the sutures. No corneal perforation,
infectious keratitis or wound gape occurred.
CONCLUSION: Corneal-scleral limbal wedge
resection with compression suture is a safe, effective treatment for poor
patients with high irregular corneal astigmatism after corneal-scleral
penetrating injury. Retinoscopy can prove particularly useful for high
irregular corneal astigmatism when other measurements are not amenable.
KEYWORDS: wedge resection; irregular corneal
astigmatism; ocular trauma
Citation: Du J, Zheng GY,
Wen CL, Zhang XF, Zhu Y. Long-term outcomes of wedge resection at the limbus for
high irregular corneal astigmatism after repaired corneal laceration. Int J Ophthalmol 2016;9(6):843-847
INTRODUCTION
Eye injury is frequently encountered
in departments of ophthalmology. In the Beijing area, the rate of adults aged 40y
or more suffering from eye injuries reached nearly 3% in the past 5y[1]. Zhou et al[2] reported that the rate of ocular trauma in a rural
population of northern China was 2.1%. Between 2006 and 2011, a total of 5 541
434 patients with ocular trauma visited emergency departments in the United
States[3].
The cornea, located on the front
surface of the eyeball, is most susceptible to ocular trauma, which damages its
transparency and regularity, and can result in astigmatism. Compared to
congenital corneal astigmatism, traumatic corneal astigmatism is high and
irregular. White scars of different sizes and shapes are also left on the
cornea after debridement and surgery involving sutures, which not only affects
the appearance, but also causes high irregular corneal astigmatism.
There are several options for the
management of astigmatism[4-6].
Common methods for nonsurgical correction of astigmatism involve the use of
spectacles or contact lenses. Aberrations and prismatic effects caused by an
uneven corneal surface and high irregular astigmatism causes patients with
spectacles to suffer intolerable levels of aniseikonia. Contact lenses are also
difficult to be widely used because topographic irregularities make them
difficult to fit, they are also limited in their ability to correct
astigmatism, and may also cause discomfort to the patient. Surgical management
of corneal astigmatism includes photorefractive keratectomy (PRK), laser in situ keratomileusis (LASIK), toric
intraocular lens (IOL) implantation, conductive keratoplasty (CK), corneal
wedge resection, and relaxing incision. All of these approaches have proven to
be effective, although each has its own complications[7-10], besides, the costs of these surgeries are relatively
expensive.
Patients with eye injuries are
mainly industry and agriculture production workers and school-aged children,
most of whom have a poor economic status. They require a simple, inexpensive,
and effective method for treating their vision problem. Corneal limbus wedge
resection for the treatment of corneal astigmatism is one such appropriate
option. Previous researchs have reported that patients with pellucid marginal
degeneration or keratoconus after penetrating keratoplasty were treated with wedge resection[11-16], here we describe a
case series in which we performed corneal limbal wedge resection for treating
traumatic corneal astigmatism in patients from poor economic conditions. To our
knowledge, no other study has evaluated the effects of wedge resection to
correct high irregular astigmatism after eye injury.
SUBJECTS AND METHODS
This retrospective case series
included 10 eyes (10 subjects) with traumatic corneal astigmatism treated with
corneal limbal wedge resection from March 1, 2005 to June 30, 2008. The study
was approved by the Institutional Ethics Committee of Medical College of
Zhengzhou University. All patients related information were obtained from
patient consent.
Subjects All patients presented with a cornea penetrating injury, and
were implanted with IOL
because of traumatic cataract, some also underwent coreoplasty in order to make
the pupil near normal size. Inclusion criteria: patients with no strabismus, no
amblyopia, no glaucoma, no uveitis, no keratitis, no history of ocular surgery,
and no long-term use of ocular medicine before the current trauma. All
treatments were performed at least 6mo after complete suture removal from the
corneal wound; the corneal laceration extended no more than 3 mm beyond the corneal
limbus, and all eyes had astigmatism ≥ 3.00 diopter (D). Data collected
included age, sex, injured eyes, size and shape of the wound, preoperative
uncorrected visual acuity (UCVA), preoperative best corrected visual acuity
(BCVA), retinoscopy optometry results, operative methods, postoperative UCVA,
postoperative BCVA, and postoperative retinoscopy optometry results. All
patients were examined by the same experienced optometrist using retinoscopy to
determine the maximum degree of irregular astigmatism, and the steepest and
flattest meridians. Scar size was measured using calipers under surgical
microscope. UCVA and BCVA were evaluated on the Snellen’s scale and converted
to logMAR visual acuity for analysis.
Methods The paired arcuate incisions were placed at 0.5-1.0 mm before
the corneal-scleral intersection, centered on the axis of the flatter meridian
of the cornea, with a range of 45°-90°, and a depth of two-thirds to
three-quarters of the corneal thickness. A thin sliver of tissue with a width
of 0.5-1 mm was excised from the cornea. The wound was closed with a 10-0
polypropylene suture; all sutures were left in place, and the knot was buried
in the cornea. During the operation, we used a Placido disk. The tightness of
sutures was adjusted in order to make the image of the Placido disk on the
cornea appeared as regular concentric circles (Figures 1, 2). All surgeries were
performed by an experienced specialist (Zheng
GY). During the period of 4wk after operation, tobramycin-dexamethasone
eye drops and pranoprofen eye drops were administered four times a day, the
former should be tapered in the period.
Figure 1 Preoperative image of Placido
disk on the cornea Before wedge resection at the corneal limbus,
the image of Placido disc in the traumatic corneal scarring showed irregular
concentric circles.
Figure 2 Postoperative image of Placido
disk on the cornea After wedge resection at the corneal
limbus, the image of the Placido disc in the traumatic corneal scarring showed
concentric circles.
Statistical
Analysis Descriptive data are shown as the
mean±standard deviation (SD). A paired
Student’s t-test was used to compare preoperative
and postoperative data. A P value less than 0.05 was considered
significant.
RESULTS
Ten eyes of 10 patients were
enrolled in this study. The age at the time of surgery was 20.60±11.34y (range:
7-34y); 5 patients were children and 5 were adults. All of the children were
male, and the average age was 10.20±2.86y (range: 7-14y). Adults included 3 men
and 2 women; the average age was 31.00±3.24y (range: 27-34y). The size of scar
was 5.05±2.09 mm (range: 3.0-9.5 mm). The shape of scar was classified into three categories:
zigzag line, beeline, and triangle, with 6 eyes, 3 eyes and 1 eye respectively
(Figure 3). There were 6 eyes of scar crossed the central 5-mm area of cornea,
and 4 eyes located outside the area. The average follow-up period was 37.8±15.4mo
(range: 20-61mo). A summary of the patients’ characteristics can be found in
Table 1.
Table 1 Clinic data of patients with high irregular
astigmatism after repaired corneal laceration
|
No. |
Sex |
Age (a) |
Eye |
Shape
of scar |
Size
of scar (mm) |
Lens
status |
Preoperative UCVA |
Preoperative BCVA |
Preoperative retinoscopy |
Follow-up period
(mo) |
|
1 |
M |
28 |
L |
Zigzag
line |
9.5 |
IOL |
CF/50
cm |
0.25 |
+1.00/-7.50×60 |
53 |
|
2 |
F |
34 |
R |
Zigzag
line |
4.5 |
IOL |
0.15 |
0.3 |
+0.50/-4.00×75 |
61 |
|
3 |
F |
33 |
R |
Beeline |
3.5 |
IOL |
0.3 |
0.8 |
+0.50/+3.00×65 |
37 |
|
4 |
M |
8 |
L |
Zigzag
line |
4.0 |
IOL |
0.08 |
0.3 |
0/+4.50×180 |
21 |
|
5 |
M |
33 |
L |
Triangle |
6.5 |
IOL |
0.05 |
0.12 |
+1.75/-6.00×180 |
42 |
|
6 |
M |
7 |
L |
Zigzag
line |
7.0 |
IOL |
CF/60
cm |
0.08 |
+3.25/-6.75×65 |
39 |
|
7 |
M |
12 |
R |
Zigzag
line |
4.0 |
IOL |
0.1 |
0.3 |
+1.75/-5.00×150 |
23 |
|
8 |
M |
27 |
L |
Beeline |
3.0 |
IOL |
0.15 |
0.5 |
-1.00/-4.00×5 |
57 |
|
9 |
M |
10 |
R |
Beeline |
3.0 |
IOL |
0.3 |
0.6 |
-0.50/+3.00×90 |
20 |
|
10 |
M |
14 |
L |
Zigzag
line |
5.5 |
IOL |
0.2 |
0.4 |
+0.50/-5.50×150 |
25 |
M: Male; F: Female; L: Left; R: Right;
IOL: Intraocular lens; UCVA: Uncorrected visual acuity; BCVA: Best corrected visual
acuity.
Figure 3 Schematic diagrams of 3 shapes
of traumatic corneal scars.
The mean postoperative UCVA at the
last follow-up was +0.43±0.22 logMAR (range: +0.10 to +0.80
logMAR), and the mean preoperative UCVA was +1.07±0.55
logMAR (range: +0.50 to +2.00 logMAR); the UCVA was significantly better after
the surgery (t=5.727, P=0.000). The mean postoperative BCVA at the last follow-up was +0.15±0.17
log MAR (range: 0 to +0.50 logMAR), and the mean preoperative BCVA was +0.50±0.30 logMAR
(range: +0.10 to +1.10 logMAR); this difference was statistically significant (t=6.194,
P=0.000; Figures 4, 5).
Figure 4 Scatterplot of UCVA (logMAR)
pre- and postoperatively.
Figure 5 Scatterplot of BCVA (logMAR)
pre- and postoperatively.
The
mean astigmatism power as measured by retinoscopy was -2.03±2.27 D postoperatively,
at the last follow-up (range: -4.50 to +1.25 D), which was not statistically
significantly different (t=-1.076，P=0.310) from the
-2.83±4.52 D (range: -7.50 to +4.50 D) preoperative value. The mean spherical equivalent
refraction (SE) was -0.74±1.61 D (range: -3.25 to +1.625 D) postoperatively, at
the last follow-up, compared to -0.64±1.89 D (range -3.00 to +2.25 D)
preoperatively. This
difference was also not statistically significant (t=0.543,
P=0.601; Figures 6, 7).
Figure 6 Scatterplot of astigmatism
power pre- and postoperatively.
Figure 7 Scatterplot of spherical equivalent
(SE) pre- and postoperatively.
Safety In one case, a suture was removed
postoperatively because the suture was too tight; a loose suture was removed
and tied again in two cases. Two cases
presented with mild pannus near the sutures; however, long term
follow-up showed no growth of the corneal pannus. There were no other complications, such as corneal perforation
intraoperatively, or infectious keratitis and wound gape postoperatively.
DISCUSSION
The common methods of evaluating
corneal curvature are photokeratometry, corneal topography, and optometry.Photokeratometry requires at
least a 3-mm area with transparent and smooth surface of the central cornea for
measurement, but the area is often damaged when eye injuries occur.
Scanning-slit corneal topography (Obscan II, Bausch & Lomb, Rochester, NY,
USA) cannot obtain stable topography with an uneven corneal surface. Automatic
optometry can also not be applied to a corneal scar. Therefore, retinoscopy is used to examine the curvature of a traumatized cornea. Since
astigmatism of the injured eye is mainly derived from traumatized cornea,
corneal astigmatism correction should improve the patients' visual acuity.
Wedge resection induces astigmatism
in the meridian of surgery. van Rij and Waring[17] pointed out that wedge resection
closed by sutures in the anterior part of the cornea removes more tissue from
the anterior part than from the posterior part, thereby producing a depression
of the cornea limbus and a steepening of the central cornea in the surgical
meridian. In the opposite meridian, the cornea becomes flattened. Since corneal
wedge resection was first described as a treatment for astigmatism by Troutman[18] in 1973, researchers
have applied it to correct corneal astigmatism. Over the years, there have been
several reports of treatment of high astigmatism after penetrating keratoplasty
by corneal wedge resection[11-13].
de la Pazet al[11] reported a study of 22 eyes that underwent wedge
resection in the host corneal tissue for high irregular astigmatism after
penetrating keratoplasty for keratoconus. They found the lowest degree of
astigmatism at 3y postoperatively, with a tendency toward regression at 5y
postoperatively. MacLeanet al[14] applied wedge excision to correct
corneal astigmatism caused by pellucid
marginal degeneration; the mean keratometric astigmatism was 13.8 D (range:
8-25 D) preoperatively, 1.4 D (range: 0.5-4 D) at 3-12mo postoperatively, and
2.1 D (range: 0.5-5.5 D) at 14-138mo in the long-term follow-up.
Researchers
have also applied wedge resection and beveled penetrating relaxing incision for
the treatment of corneal astigmatism caused by pellucid marginal corneal
degeneration. The mean keratometric astigmatism was reduced from 15.1 D
preoperatively to 4.6 D at 6mo postoperatively, and was stable at further
follow-ups[[15]. There have also been reports on the use of
femtosecond-laser arcuate wedge-shaped resection for the correction of high
astigmatism[19-20], but the cost was too high, and the effect
was not superior to those of other astigmatism correction surgeries.
To our
knowledge, no study has evaluated the effects of wedge resection in the
treatment of high irregular astigmatism after corneal laceration. In our study,
we found the mean astigmatism power to be reduced from -2.83±4.52 D (range:
-7.50 to +4.50 D) preoperatively to -2.03±2.27D
(range: -4.50 to +1.25 D) at 20-61mo in the long-term follow-up. Over long-term follow-up, the mean
decrease of astigmatism in the present study was 2.33±0.59
D (range, 1.50-3.25 D), which was different from that reported by previous
studies (reaching more than 10 D). One reason for this may be the different
method used for detecting astigmatism: astigmatism changes in other reports
were mainly evaluated based on the change of corneal curvature, while
astigmatism changes reported in this study were based on the results of
retinoscopy. Another reason may be the difference in the location of the
surgical incision: the
incisions in this study were made on the corneal limbus, while those reported
in literature were closer to the center of the cornea.
Some researchers also assessed the
effect of wearing rigid gas permeable contact lenses on correcting irregular
astigmatism and providing increased visual acuity for patients with traumatic
corneal scarring. In their study, only 22.2% patients had a successful fit; the
remaining patients all complained of ocular discomfort, some found it
inconvenient to take care of the lenses, while others with good visual acuity
in the fellow eye did not want the inconvenience of a lens[21].
Corneal wedge resection also has its
disadvantages: the scope for correction of astigmatism is limited, and the
choice and tightness of the sutures require serious consideration by the
surgeon. In our study, the first case was closed up with 10-0 nylon sutures,
and a rapid refractive regression appeared 6mo after surgery. The nylon line
material is strongly elastic, while polypropylene suture material is not
elastic and the tension of the suture was therefore more intact. Thus, we
replaced the nylon sutures with polypropylene sutures for the patient, and for
the next 9 patients, 10-0 polypropylene sutures were used. The tightness of all
sutures on 1 incision should be uniform, as the effect would otherwise be
compromised. Among our cases, 2 developed mild pannus related to the large
suture span, but the range of pannus was limited with no sign of progressive
growth.
In conclusion, corneal limbal wedge
resection is a safe, moderately effective, and inexpensive treatment for high
irregular corneal astigmatism after corneal-scleral penetrating injury.
Retinoscopy may prove particularly useful for patients with high irregular
corneal astigmatism when other measurement approaches are not feasible. In this
study, some patients with poor compliance were not included in the analysis.
Hence, more cases are needed to evaluate the relationship between the length of
incision, the width of incision, and the correction of astigmatism, and to
improve the surgical correction of astigmatism further.
ACKNOWLEDGEMENTS
Foundation: Supported by Science and Technology Research Project of
Henan Province (No. 102102310117).
Conflicts of Interest: Du J, None; Zheng
GY, None; Wen
CL, None; Zhang
XF, None; Zhu
Y, None.
REFERENCES
1 Wang JD, Xu L, Wang
YX, You QS, Zhang JS, Jonas JB. Prevalence and incidence of ocular trauma in
North China: The Beijing Eye Study. Acta
Ophtalmol 2012;90(1):e61-e67. [CrossRef] [PubMed]
2 Zhou J, Wang FH, Lu H,
Liang YB, Wang NL. Ocular trauma in a rural population of North China: The
Handan Eye Study. Biomed Environ Sci
2015;28(7):495-501. [PubMed]
3 Haring RS, Canner JK,
Haider AH, Schneider EB. Ocular injury in the United States: emergency
department visits from 2006-2011. Injury 2016;47(1):104-108.
[CrossRef] [PubMed]
4 Lee BS, Lindstrom RL,
Reeves SW, Hardten DR. Modern management of astigmatism. Int Ophthalmol Clin 2013;53(1):65-78. [CrossRef] [PubMed]
5 Goggin M, Alpins N,
Schmid LM. Management of irregular astigmatism. Curr Opin Ophthalmol 2000;11(4):260-266. [CrossRef]
6 Read SA, Vincent SJ,
Collins MJ. The visual and functional impacts of astigmatism and its clinical
management. Ophthalmic Physiol Opt 2014;34(3):267-294. [CrossRef] [PubMed]
7 Toda I, Yamamoto T,
Ito M, Hori-Komai Y, Tsubota K. Topography-guided ablation for treatment of
patients with irregular astigmatism. J
Refract Surg 2007;23(2):118-125. [PubMed]
8 Xu W, Ye P, Yao K, Ma
J, Xu H. Conductive keratoplasty for the treatment of astigmatism induced by
corneal trauma or incision. J Refract
Surg 2010;26(1):33-42. [CrossRef] [PubMed]
9 Mozayan E, Lee JK.
Update on astigmatism management. Curr
Opin Ophthalmol 2014;25(4):286-290. [CrossRef] [PubMed]
10 Maedel S, Hirnschall
N, Chen YA, Findl O. Rotational performance and corneal astigmatism
correction during cataract surgery: aspheric toric intraocular lens versus
aspheric nontoric intraocular lens with opposite clear corneal incision. J Cataract Refract Surg 2014;40(8):135513-135562. [CrossRef] [PubMed]
11 de la Paz MF, Sibila
GR, Montenegro G, de Toledo JA, Michael R, Barraquer R, Barraquer J. Wedge
resection for high astigmatism after penetrating keratoplasty for keratoconus:
refractive and histopathologic changes.Cornea
2010;29(6):595-600. [CrossRef]
12 IIari L, Daya SM.
Corneal wedge resection to treat progressive keratoconus in the host cornea
after penetrating keratoplasty. J Cataract
Refract Surg 2003;29(2):395-401. [CrossRef]
13 Ezra DG, Hay-Smith G,
Mearza A, Falcon MG. Corneal wedge excision in the treatment of high
astigmatism after penetrating keratoplasty. Cornea
2007;26(7):819-825. [CrossRef] [PubMed]
14 MacLean H, Robinson
LP, Wechsler AW. Long-term results of corneal wedge excision for pellucid
marginal degeneration. Eye (Lond) 1997;11(5):613-617. [CrossRef] [PubMed]
15 Busin M, Kerdraon Y,
Scorcia V, Zambianchi L, Matteoni S. Combined wedge resection and beveled
penetrating relaxing incisions for the treatment of pellucid marginal corneal
degeneration. Cornea
2008;27(5):595-600. [CrossRef] [PubMed]
16 Maccheron L J, Daya
SM. Wedge resection and lamellar dissection for pellucid marginal degeneration.
Cornea 2012;31(6):708-715. [CrossRef] [PubMed]
17 van Rij G, Waring GO.
Changes in corneal curvature induced by sutures and incisions. Am J Ophthalmol 1984;98(6):773-783. [CrossRef]
18 Troutman RC.
Microsurgical control of corneal astigmatism in cataract and keratoplasty. Trans Am Acad Ophthalmol Otolaryngol
1973;77(5):OP563-OP572. [PubMed]
19 Buzzonetti L,
Petrocelli G, Laborante A, Mazzilli E, Gaspari M, Valente P. Arcuate keratotomy
for high postoperative keratoplasty astigmatism performed with the intralase
femtosecond laser. J Refract Surg 2009;25(8):709-714.
[CrossRef]
20 Ghanem RC, Azar DT.
Femtosecond-laser arcuate wedge-shaped resection to correct high residual
astigmatism after penetrating keratoplasty. J
Cataract Refract Surg 2006;32(9):1415-1459. [CrossRef] [PubMed]
21 Zheng B, Shen L,
Walker MK, Zhang Z, Zheng J, She X, Zhou J, Xu Z, Chen Y. Clinical evaluation
of rigid gas permeable contact lenses and visual outcome after repaired corneal
laceration.Eye Contact Lens
2015;41(1):34-39. [CrossRef] [PubMed]
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