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Corneal asphericity changes after implantation of intrastromal corneal ring segments

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Session Details

Session Title: Presented Poster Session: Quality of Vision/Miscellaneous

Venue: Poster Village: Pod 3

First Author: : C.Durmaz Engin TURKEY

Co Author(s): :    C. Utine   Z. Ayhan           

Abstract Details

Purpose:

To evaluate the visual, refractive and corneal asphericity changes after implantation of intrastromal corneal ring segments (ICRS) for visual rehabilitation

Setting:

Dokuz Eylul University, Department of Ophthalmology, Cornea Division

Methods:

Patients with keratoconus and high corneal astigmatism who underwent ICRS implantation for optical and visual rehabilitation were reviewed retrospectively. A total of 25 eyes of 20 keratoconus patients and 3 eyes of 2 patients with high astigmatism were identified. Changes in uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive errors, anterior and posterior corneal asphericity values measured with Scheimpflug topography (Pentacam, Oculus®) were evaluated retrospectively.

Results:

After creation of intrastromal tunnels of 5.01±0.03mm inner and 5.71±0.03mm outer diameter,1 or 2 ICRS of 150µ–350µ thickness and 90° - 210°arc length were implanted.Preoperative mean UDVA of 0.15±0.1 and CDVA of 0.32±0.07 were increased postoperatively to 0.60±0.27 and 0.70±0.15 Snellen lines,respectively(p<0.01). Mean preoperative spherical equivalent of -5.85±4.60D decreased to -2.45±2.28D (p=0.05) and mean preoperative refractive astigmatism of -6.10±2.22D decreased to -2.18±2.19D postoperatively(p<0.01).Mean Qant value was -0.98±0.50 preoperatively and -0.42±0.50 postoperatively(p<0.01) while mean Qpost value was -0.98±0.49 preoperatively and -0,88±0.52 postoperatively (p=0.62).

Conclusions:

ICRS implantation seem to approximate the anterior corneal asphericity of “advanced prolate” shape to “the perfect prolate” Q value of -0.52 and human corneal “ideal Q value” of -0.46 as was seen in this study. This improvement in corneal asphericity may have a role in significantly improved UDVA and CDVA, in addition to the effect of decreased refractive cylinder. No statistically significant difference in posterior corneal asphericity was observed.

Financial Disclosure:

NONE

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