Outcomes of phototherapeutic keratectomy after cataract surgery in granular corneal dystrophy type 2

Session Details

Session Title: Presented Poster Session 05: Cataract Surgery Outcomes / IOL Technology

Session Date/Time: Saturday 13/09/2014 | 15:00-17:00

Paper Time: 15:30

Venue: Pod 2 (Poster Village)

First Author: : F.Oya JAPAN

Co Author(s): :    T. Soma   Y. Oie   N. Meda   K. Nishida     

Abstract Details

Purpose:

Granular corneal dystrophy type 2 (GCD2) is an autosomal-dominant disorder in which hyaline and amyloid deposits develop in the shallow middle stromal layer. Phototherapeutic keratectomy (PTK) is performed to treat diffuse superficial haze, which threatens visual acuity (VA), in the optical zone. If stromal haze and cataract are present in an aged eye with GCD2, PTK generally is performed before cataract surgery. However, intraocular lens (IOL) power calculations for cataract surgery after PTK are difficult due to anterior corneal curvature changes. Because K-values measured by autokeratometry tend to be overestimated after PTK, hyperopic refractive errors often occur when the IOL power is calculated using the SRK/T formula. We hypothesized that performing cataract surgery before PTK may avoid this problem. We evaluated the visual function and postoperative refractive errors in patients with GCD2 and cataract who underwent cataract surgery 3 months before PTK.

Setting:

Osaka University Hospital, Suita, Japan.

Methods:

The medical records of 11 eyes of 10 patients (2 men, 8 women; mean age, 70 ± 7.5 years) with GCD2 and cataract were evaluated retrospectively. All patients had undergone PTK 3 months after cataract surgery from August 2012 to September 2013. All follow-up periods were longer than 3 months after PTK. All patients had nuclear cataracts of grades 1 to 2.5 by the Emery-Little classification. We calculated the IOL power with the SRK/T formula using the IOLMaster (Carl Zeiss Meditec, Jena, Germany).We used the transepithelial photorefractive keratectomy mode in the VISX S4 IR (VISX Inc., Santa Clara, CA) for PTK to avoid central islands. The logarithm of the minimum angle of resolution (logMAR) VA was measured before and after cataract surgery and after PTK. Refractive errors were measured after cataract surgery and PTK. Astigmatism (regular, asymmetric, and higher order components) was measured before cataract surgery and after PTK with 3- and 6-mm pupillary diameters and were analyzed by Fourier analysis with anterior optical coherence tomography (SS-1000, Tomey Corporation, Nagoya, Japan). Complications from cataract surgery and PTK were investigated.

Results:

The mean logMAR VAs were 0.42±0.21, 0.41±0.18, and 0.16±0.14 before and after cataract surgery and after PTK, respectively. The VA improved significantly (P=0.0020, P=0.0049, Bonferroni-adjusted t-test) after PTK compared with before and after cataract surgery. The mean prediction errors (MPE) and mean absolute errors (MAE) after cataract surgery were -0.29±0.66 and 0.55±0.45 diopters (D), respectively; those after PTK were 1.25±0.86 and 1.32±0.74 D, respectively. There was no significant difference in the astigmatism with a 3-mm pupil between before cataract surgery and after PTK, whereas the asymmetry component with a 6-mm pupil significantly (P=0.020) increased after PTK. No complications associated with cataract surgery developed. One patient had a suspected methicillin-resistant Staphylococcus aureus corneal infection 1 month after PTK, which resolved rapidly with topical antibiotics.

Conclusions:

Performing cataract surgery before PTK may be an effective procedure that results in small refractive errors after cataract surgery and mild postoperative astigmatism after PTK in patients with GCD2 and cataract.

Financial Interest:

NONE