Refractive and corneal aberrometric changes after intracorneal ring implantation in corneas with pellucid marginal degeneration.
OBJECTIVE
To evaluate refractive, visual, and aberrometric changes in corneas with pellucid marginal degeneration (PMD) implanted with intracorneal ring segments (ICRS) during a 6-month follow-up.


METHODS
Retrospective, consecutive case series.


METHODS
We included 21 consecutive eyes of 15 patients ranging in age from 21 to 73 years old and with a diagnosis of PMD. This diagnosis was made on the basis of slit-lamp (inferior corneal thinning), corneal topography ("butterfly" pattern), and refractive findings (significant against-the-rule astigmatism with best spectacle-corrected visual acuity loss).


METHODS
A multicenter, retrospective analysis of patients undergoing ICRS implantation for the management of PMD in 4 ophthalmologic centers was performed. Surgery was indicated in all cases because of reduced best spectacle-corrected visual acuity (BSCVA) and/or contact lens intolerance or dissatisfaction. Mechanical corneal tunnelization was performed in 7 eyes and femtosecond laser-assisted tunnelization in 14 eyes. Intacs were implanted in only 3 eyes whereas KeraRings in 18 eyes. Refractive and corneal aberrometric changes were analyzed during a 6-month follow-up.


METHODS
Uncorrected corrected visual acuity (UCVA) and BSCVA, refraction, keratometry, and root mean square (RMS) for different kinds of corneal aberrations.


RESULTS
The UCVA did not improve at 6 months after surgery (P = 0.11). The BSCVA increased from a mean preoperative value of 0.54 to a mean postoperative value of 0.75 (P = 0.06). At 6 months, 44.44% of eyes gained > or =2 lines of BSCVA. Sphere (P = 0.02), cylinder (P<0.01), and spherical equivalent (P<0.01) were reduced significantly after surgery (P< or =0.02). Mean keratometry decreased significantly from 44.95 diopters (D) preoperatively to 43.19 D at 6 months postoperatively (P<0.01). The RMS values for astigmatism, higher order residual, and coma-like aberrations were significantly reduced with surgery (P = 0.03). In addition, significant negative correlations of preoperative RMS astigmatism (r = -0.90) and primary spherical aberration (r = -0.86) with postoperative BSCVA were also found. Segment ring explantation was performed in a total of 4 eyes owing to poor visual outcome.


CONCLUSIONS
Implantation of an ICRS is an effective option for the treatment of 2nd-order and higher aberrations in corneas with PMD. Preoperative corneal astigmatism and spherical aberration seem to be limiting factors for a good visual outcome.


BACKGROUND
The authors have no proprietary or commercial interest in any materials discussed in this manuscript.
Piñero
David P
DP
Vissum/Instituto Oftalmológico de Alicante, Spain.
Alio
Jorge L
JL
Morbelli
Hector
H
Uceda-Montanes
Antonio
A
El Kady
Bassam
B
Coskunseven
Efekan
E
Pascual
Inmaculada
I
D000328:Adult; D000368:Aged; D003315:Cornea / Q000503:physiopathology* / Q000601:surgery; D003316:Corneal Diseases / Q000503:physiopathology / Q000601:surgery*; D003319:Corneal Stroma / Q000601:surgery; D019781:Corneal Topography; D020878:Device Removal; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D012029:Refraction, Ocular / Q000502:physiology*; D012189:Retrospective Studies; D019738:Surgically-Created Structures; D014792:Visual Acuity / Q000502:physiology*; D055815:Young Adult