FULL RING INTRACORNEAL IMPLANTATION IN PMD

Sahar Mojaled Nobari( PhdC), Consuelo Villena(PhD), Khosrow Jadidi (PhD)

INTRODUCTION

MyoRing is a full ring intracorneal implant that

inserts into the cornea using the Pocketmaker

Microkeratome or femtosecond laser. The use of

MyoRing implantation has proven to be safe and

effective procedure in patients with high myopia,

post lasik ectasia and keratoconus.

INTRODUCTION

This study evaluates the visual and refractive

outcomes as well as the patient´s satisfaction and

ocular symptoms after MyoRing implantation in

patients with Pellucid Marginal Degeneration

(PMD). To our knowledge this is the first study on

MyoRing implantation in patients with PMD

PATIENTS & METHODS Retrospective study : 15 eyes of 15 patients,(11males & 4 females) ranging in age from

22 to 49 years old

Surgical technique : MyoRing implantation using PocketMaker Microkeratome

Follow-up : 10 months (range 6-12 months)

Inclusion criteria : poor visual acuity with spectacle,contact lens intolerance or

dissatisfaction, clear central cornea, minimum corneal thickness 360 microns and mean

keratometry between 45 to 52 diopter

Exclusion criteria : other ocular disease, pregnancy, diabetes , previous ocular surgery

Diagnosis : slit lamp examination ( inferior corneal thining, ectasia above the area the

maximum thining ), Corneal topography( butterfly or kissing birds pattern) and

refractive finding (against–the-rule astigmatism with CDVA loss)

Patients were asked about their visual symptoms and general satisfaction , based on 6-

point subjective likert scale to score them

Visual and Refractive OutcomesParameter Preoperative postoperative p-value

UCVA (log MAR)Mean ± SD 1.13 ± 0.21 0.24 ± 0.12 <0.001

Range 0.7 to 1.30 0 to 0.50

BCVA (log MAR)Mean ± SD 0.40 ± 0.12 0.18 ± 0.09 <0.001

Range 0.3 to 0.7 0 to 0.4

Sphere(D)Mean ± SD -3.20 ± 3.4 0.01 ± 1.9 <0.001

Range -10 to 0 -5.00 to 2.50

Cylinder(D)Mean ± SD -5.50 ± 1.2 -1.70 ± 1.00 <0.001

Range -7.00 to -3.00 -3.50 to 0

Spherical Equivalent(D)Mean ± SD -6.00 ± 3.6 -0.70 ± 1.9 <0.001

Range -13.00 to -1.75 -6.00 to +1.75

Mean of the Keratometric (K) Values Preoperatively and Postoperatively as Well as the Amount of Reduction.

K- Readings Preoperative Postoperative Pre-Postǂ P-value

Kmax (D) 51.1 ± 2.4 46.1 ± 2.00 5.00 D <0.001

Kmin (D) 44.8 ± 2.00 43.7 ± 2.1 1.10 D <0.001

Kaverage (D) 48.0 ± 2.2 44.0 ± 2.6 4.00 D <0.001

A significant reduction was observed in maximum, minimum and average keratometry after MyoRing implantation.

Visual Symptoms and Patient´s Satisfaction Score Postoperatively (based on 6-point likert scale)

parameters No Very low Low Moderate High Very high

Halo (%) 5 (33.3) 5 (33.3) 2 (13.3) 2 (13.3) 1 (6.7) 0

Glare (%) 5 (33.3) 3 (20) 5 (33.3) 1 (6.7) 1 (6.7) 0

Night Vision (%) 6 (40) 2 (33.3) 3 (20) 4 (26.7) 0 0

Fluctuation (%) 9 (60) 4 (26.7) 2 (6.7) 0 0 0

Activity Limitation (%) 12 (80) 2 (13.3) 1 (6.7) 0 0 0

Overall Satisfaction (%) 0 0 1(6.7) 2(13.3) 5 (33.3) 7 (46.7)

CONCLUSION MyoRing implantation by means of PocketMaker

Microkeratome appears to be a safe and effective method for treating pellucid marginal degeneration.

Both UCVA and BSCVA improved significantly. The improvement in UCVA was remarkable ( 9 lines of snellen acuity)

The considerable corneal flattening is due to the circular shape of MyoRing which leads to a more significant arc-shortening effect on the cornea

All patients were satisfied with MyoRing implantation

Further randomized, prospective studies with longer follow-up period is recommended to evaluate the stability of MyoRing implantation and its impact on disease progression