This study evaluated the outcomes of implanting intrastromal corneal ring segments (ICRS) in 25 eyes of 20 patients with corneal ectasia after refractive surgery. Post-operatively, uncorrected distance visual acuity significantly improved from 20/185 to 20/66 on average and corrected distance visual acuity significantly improved from 20/125 to 20/40 on average. Keratometry and corneal asphericity values also significantly improved. The study found that ICRS implantation can effectively treat corneal ectasia after refractive surgery by improving vision and corneal shape.

1. Intrastromal corneal ring segment implantation
for ectasia after refractive surgery
Leonardo Torquetti, MD, PhD, Paulo Ferrara, MD, PhD
PURPOSE: To evaluate the clinical outcomes of implantation of Ferrara intrastromal corneal ring
segments (ICRS) in patients with corneal ectasia after refractive surgery.
SETTING: Private clinic, Belo Horizonte, Brazil.
METHODS: Charts of patients with corneal ectasia after refractive surgery were retrospectively
reviewed. The following parameters were studied: uncorrected distance visual acuity (UDVA),
corrected distance visual acuity (CDVA), keratometry, corneal asphericity, and pachymetry. All
patients were evaluated by Scheimpflug scanning-slit tomography (Pentacam).
RESULTS: Charts of 25 eyes (20 patients) with corneal ectasia (20 after laser in situ keratomileusis,
4 after radial keratotomy, 1 after photorefractive keratectomy) were reviewed. Postoperatively, the
mean UDVA increased from 20/185 to 20/66 (P Z .005) and the mean CDVA, from 20/125 to 20/40
(P Z .008). The mean asphericity decreased from À0.95 preoperatively to À0.23 postoperatively
(P Z .006). The mean pachymetry at the apex of the cornea increased from 457.7 mm G 48.7 (SD)
preoperatively to 466.2 G 49.8 mm postoperatively (P Z .025) and the mean pachymetry at the
thinnest point, from 436.3 G 46.2 mm to 453.9 G 49.3 mm (P Z .000). The mean keratometry
decreased from 45.41 G 5.63 diopters (D) to 42.88 G 4.44 D, respectively; the decrease was
statistically significant (P Z .000).
CONCLUSION: Intrastromal corneal ring segment implantation significantly improved UDVA and
CDVA in patients with corneal ectasia.
Financial Disclosure: Dr. Torquetti has no financial or proprietary interest in any material or method
mentioned. Additional disclosures are found in the footnotes.
J Cataract Refract Surg 2010; 36:986–990 Q 2010 ASCRS and ESCRS
Corneal ectasia is an infrequent but potentially serious
complication of refractive surgery and occurs more
commonly after laser in situ keratomileusis
(LASIK).1–3
After LASIK, the cornea is structurally
weakened, not only by the laser central stromal abla-
tion but also by the creation of the flap. The cornea
may assume an irregular conical shape, and this leads
to a decrease in visual acuity secondary to high irreg-
ular astigmatism, as occurs in primary ectatic corneal
disorders such as keratoconus.4,5
Even though corneal ectasia is relatively rare after
LASIK, it can have a profoundly negative effect on
the refractive properties of the cornea. The cause and
the biomechanical changes that induce keratectasia
after refractive surgery are unknown. The cause of
corneal ectasia has not been clearly established, al-
though collagen abnormalities, as seen in keratoconus,
have been reported. The disease usually evolves with
progressive deterioration in uncorrected distance
visual acuity (UDVA) and corrected distance visual
acuity (CDVA) caused by the irregular astigmatism
induced by the corneal ectasia.6
Several possible alternatives to manage post-LASIK
corneal ectasia have been reported, including sclera-
fitted gas-permeable contact lenses,3,7
collagen
Submitted: October 16, 2009.
Final revision submitted: December 10, 2009.
Accepted: December 10, 2009.
From a private clinic, Belo Horizonte, Brazil.
Additional financial disclosuce: Dr. Ferrara has a financial interest in
the Ferrara intrastromal cornea ring.
Corresponding author: Paulo Ferrara, MD, PhD, Paulo Ferrara Eye
Clinic, Contorno Avenida 4747, Suite 615, Lifecenter, Funciona´rios,
Belo Horizonte MG 30110-031, Brazil. E-mail: pferrara@ferrararing.
com.br.
Q 2010 ASCRS and ESCRS 0886-3350/$dsee front matter
Published by Elsevier Inc. doi:10.1016/j.jcrs.2009.12.034
986
ARTICLE

2. crosslinking,8
deep lamellar keratoplasty,9
and intra-
stromal corneal ring segment (ICRS) implantation.10–
13
Intrastromal corneal ring segments were designed
to achieve a refractive adjustment by flattening the
central corneal curvature while maintaining clarity in
the central optical zone; they were first used in patients
with low myopia. Because ICRS are removable and
save tissue, the technique’s application was expanded
to eyes with corneal thinning disorders in which re-
fractive surgery is not suitable.
Implantation of ICRS has been used largely for treat-
ment of primary and secondary ectatic corneal disor-
ders. Several studies show the efficacy of ICRS in
treating many corneal conditions, such as keratoco-
nus,14–15
post-radial keratotomy ectasia,16
astigma-
tism,17
and myopia.18
The purpose of this study was to evaluate the visual
and keratometric outcomes of ICRS implantation to
correct ectasia, stabilize ectasia, or both after refractive
surgery.
PATIENTS AND METHODS
In this study, charts of patients who had Ferrara ICRS (Fer-
rara Ophthalmics) implantation were reviewed. All patients
completed at least 6 months of follow-up and had clear cen-
tral corneas and contact lens intolerance.
Patients were excluded after the preoperative examination
if they had a history of herpes, keratitis, corneal dystrophy,
diagnosed autoimmune disease, systemic connective tissue
disease, and acute or grade IV keratoconus.
Surgical Technique
The same surgeon (P.F.) performed all ICRS implantation
procedures using topical anesthesia, the manual technique,
and the Ferrara ring nomogram.14
With the patient looking
at a red light attached to the turned-off surgical microscope,
a reference point was marked in the center of the cornea. The
incision was made at the steepest meridian of the anterior
cornea surface with a calibrated diamond knife set at
approximately 80% of the corneal thickness, was determined
by Scheimpflug scanning-slit tomography (Pentacam, Ocu-
lus, Inc.). Corneal pockets were then created with a spreader
hook. One semicircular dissector was placed sequentially in
the lamellar pocket and steadily advanced by rotational
movement (counterclockwise and clockwise dissectors). Af-
ter creation of the tunnels, the ICRS was inserted in the
tunnels.
After surgery, moxifloxacin 0.5% and dexamethasone
0.1% eyedrops were used 4 times daily for 2 weeks. The pa-
tients were instructed to avoid rubbing the eye and to use
preservative-free artificial tears (polyethylene glycol 400
0.4%) frequently.
Patient Assessment
A complete ophthalmologic examination was performed
before and after surgery and included UDVA, CDVA, biomi-
croscopy, corneal topography, pachymetry, and measure-
ment of corneal asphericity using the Scheimpflug
scanning-slit tomography system.
On the first postoperative day, a slitlamp biomicroscopic
examination was performed. Wound healing and segment
migration were evaluated. At the last follow-up examina-
tion, manifest refraction, UDVA and CDVA, slitlamp, and
topographic examinations were performed.
Statistical Analysis
Statistical analysis was performed using Minitab software
(version 2007, Minitab, Inc.). The Student t test for paired
data was used to compare preoperative and postoperative
data.
RESULTS
Twenty-five eyes of 20 patients with corneal ectasia af-
ter refractive surgery were evaluated. The refractive
surgery was LASIK in 20 eyes, radial keratotomy in
4 eyes, and photorefractive keratectomy in 1 eye.
Table 1 shows the characteristics of the patients. The
mean follow-up was 39.8 months G 21.1 (SD). All pa-
tients had implantation of a single segment. The arc
ring was 160 degrees in 18 eyes and 210 degrees in 7
eyes. The ICRS segment was implanted uneventfully
in all cases.
Table 2 shows the postoperative results. The in-
crease in mean UDVA and mean CDVA from preoper-
atively to postoperatively was statistically significant
(P Z .005 and P Z .008, respectively) (Figure 1). The
decrease in mean corneal asphericity was also statisti-
cally significant (P Z .006).
The increase in the mean pachymetry at the apex of
the cornea and at the thinnest point of the cornea was
statistically significant (P Z .025 and P Z .000, respec-
tively). There was a statistically significant reduction
in keratometric values from preoperative to the last
follow-up examination (P Z .000) (Figure 2).
One patient required additional surgery to reposi-
tion the ring. There were no other complications.
DISCUSSION
The widespread use of LASIK has not resulted in nota-
bly serious complications. Despite the number of stud-
ies that support the efficacy of LASIK,19
concern about
the occurrence of postoperative keratectasia is grow-
ing. The tissue ablation and lamellar cut in LASIK
Table 1. Preoperative patient characteristics.
Parameter Value
Eyes 25
Patients 20
Sex (M/F) 13/7
Age (y)
Mean G SD 38.7 G 9.2
Range 28–57
987INTRASTROMAL CORNEAL RING SEGMENTS IN CORNEAL ECTASIA
J CATARACT REFRACT SURG - VOL 36, JUNE 2010

3. substantially weaken the mechanical strength and ef-
fective thickness of the cornea. There is concern that
at some point, the tensile strength of the cornea may
be reduced to a level that predisposes to postoperative
ectasia.20
In our study of ICRS segment implantation for
corneal ectasia after refractive surgery, there was a sig-
nificant improvement in UDVA and CDVA postoper-
atively. Moreover, there was significant increase in
corneal thickness. This can be explained theoretically
by the cornea collagen remodeling induced by ICRS
implantation.21
We also found a significant decrease in corneal as-
phericity after ICRS implantation. The mean postoper-
ative asphericity value was À0.23, which is considered
normal in the general population.22
This means that
the normal physiologic asphericity of the cornea varies
significantly among individuals, ranging from mild
oblate to moderate prolate.23,24
In an unpublished
study, we evaluated corneal asphericity changes in-
duced by ICRS implantation in eyes with keratoconus.
We found that ICRS implantation significantly re-
duced the mean corneal asphericity, from À0.85 to
À0.32. It is well known that after ablation laser proce-
dures, most corneas tend to become oblate and when
ectasia develops, the corneas usually become prolate.
However, the excess prolateness usually found in ker-
atoconus (primary) is much greater than that occur-
ring in ectasia after refractive surgery. That is the
probable reason the asphericity value after ICRS be-
comes closer to normal than when the ICRS is used
for keratoconus. Asphericity is one marker of visual
quality; a normal asphericity value after treatment
can be a predictor of improvement of quality of vision.
In our study, all eyes had significantly lower kera-
tometry values after ICRS implantation. The mean
preoperative values in such cases are usually lower
than in keratoconus (primary). This can be partially ex-
plained by the corneal flattening induced by the refrac-
tive procedure, usually in an optic zone of greater
extent than the location of the ectasia.
Most ICRS implanted in our study were conven-
tional models, having an arc ring of 160 degrees. The
ICRS in the other eyes had an arc ring of 210 degrees.
The latter is usually reserved for central cones of the
nipple type. Some ectasias assume the same topo-
graphic pattern of nipple cones, in which we usually
use a 210-degrees arc ring with excellent results.15
This ring is reserved for cases with low astigmatism
in which we want to flatten the cornea with minimal
induction of astigmatism.
There are several potential advantages of ICRS im-
plantation over keratoplasty in eyes with post-LASIK
ectasia. First, ICRS implantation avoids further laser
treatment, eliminating central corneal wound healing.
Table 2. Preoperative versus postoperative results.
Parameter Preoperative Postoperative P Value
Mean UDVA 20/185 20/66 .005
Mean CDVA 20/125 20/40 .008
Pachymetry (mm) .025
At apex
Mean G SD 457.7 G 48.7 466.2 G 49.8 .000
Range 361–542 381–559
At thinnest point
Mean G SD 436.3 G 46.2 453.9 G 49.3 .000
Range 348 to 533 370 to 548
Mean asphericity À0.95 À0.23 .006
Keratometry (D) .000
Mean G SD 45.41 G 5.63 42.88 G 4.44
Range 37.3–55.5 31.2–54.1
CDVA Z corrected distance visual acuity; UDVA Z uncorrected distance
visual acuity
print&web4C=FPO
Figure 1. Mean preoperative and postoperative UDVA and CDVA
CDVS Z corrected distance visual acuity; UDVA Z uncorrected
distance visual acuity).
print&web4C=FPO
Figure 2. Scattergram of the mean preoperative and postoperative
keratometry.
988 INTRASTROMAL CORNEAL RING SEGMENTS IN CORNEAL ECTASIA
J CATARACT REFRACT SURG - VOL 36, JUNE 2010

4. This leaves the optical center of the cornea untouched,
enhancing refractive outcomes. Second, the technique
is reversible in cases of an unsatisfactory refractive or
clinical outcomes. Third, adjustment can be performed
using thinner or thicker rings. In cases of unexpected
corneal shape changes, 1 segment can be removed or
exchanged. Fourth, it avoids the complications of
intraocular surgery.
Alio´ et al.11
found significant improvement in visual
acuity after ICRS implantation in eyes with ectasia. In
2 eyes, the UDVA was 20/40 postoperatively. In the
third eye, there was a residual refractive error; the
UDVA was 20/50 and the CDVA, 20/40.
In a post-LASIK ectasia study, Kymionis et al.8
im-
planted ICRS in eyes with a mean preoperative
UDVA of 20/100. At the last follow-up examination,
6 (75%) of 8 eyes had a UDVA 20/40 or better. At
the end of the first postoperative year, UDVA,
CDVA, and topography were stable and remained so
during the follow-up period.
Ina recentstudy of ICRSimplantation incorneaswith
pellucid marginal degeneration by Pin˜ero et al.,25
UDVA did not improve after surgery (P Z .17). The
CDVA increased significantly at 6 months (P Z .02).
Approximately 39% of the eyes gained 2 or more lines
of CDVA at 6 months; this percentage increased to
60% at 24 months. The cornea was, on average, flatter
at 6 months (P!.01), with nonsignificant posterior re-
gression of the achieved flattening (P Z .73). In our
study, the mean UDVA increased from 20/185 to 20/66
(P Z .005) and the mean CDVA, from 20/125 to 20/40
(P Z .008).
This study has potential limitations, such as the
small sample of treated eyes and the lack of a compar-
ative group. However, the results were similar to those
in post-LASIK studies in which ICRS were used for
treatment.
In conclusion, ICRS implantation in eyes with cor-
neal ectasia after refractive surgery provided satisfac-
tory visual outcomes. Larger comparative studies are
needed to confirm the results in our study.
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print&web4C=FPO
First author:
Leonardo Torquetti, MD, PhD,
Private clinic, Belo Horizonte, Brazil.
990 INTRASTROMAL CORNEAL RING SEGMENTS IN CORNEAL ECTASIA
J CATARACT REFRACT SURG - VOL 36, JUNE 2010