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Central toxic keratopathy following uneventful LASIK

Session Details

Session Title: LASIK

Session Date/Time: Wednesday 09/10/2013 | 08:00-10:30

Paper Time: 10:24

Venue: Auditorium (First Floor)

First Author: : F.Aiello ITALY

Co Author(s): :    G. Jutley   D. Robaei   V. Maurino        

Abstract Details

Purpose:

To evaluate the final visual outcomes after uneventful laser in–situ keratomileusis (LASIK) complicated by central toxic keratopathy (CTK). All cases occurred within a period of 46 days.

Setting:

Refractive Surgery Unit, Moorfields Eye Hospital, NHS Foundation Trust, London, United Kingdom.

Methods:

CTK occurred in fifteen eyes from nine patients that underwent uncomplicated LASIK. Five different high volume expert refractive surgeons from the same Institution performed the surgery. None of the patients had predisposing factors for post LASIK inflammation, including underlying connective tissue disorders. All flaps were created by a 150 kHz femtosecond laser (IntraLaser FSLaser, Intralase Corp. Irvine, CA); planned flap thickness was between 105 and 110 microns in all eyes. Nine eyes were treated with VISX CustomVue platform (Abbott medical Optics, Santa Ana, CA) and 6 eyes with Technolas®217z (Bausch and Lomb Surgical, Irvine, CA). There were no intra-operative complications. All patients were treated with the same routine post-operative topical medication regimen including Dexamethasone 0.1% eye drops, Levofloxacin 0.5% eye drops and Carmellose sodium 0.5% eye drops. All drops were administered hourly for the first 24 hours and four times a day thereafter for the first week. The diagnosis of CTK was clinical and defined as a non-inflammatory, central opacification, causing reduced visual acuity. This was further corroborated by Pentacam evaluations showing central corneal thinning and a hyperopic shift. Best-spectacle corrected visual acuity (BSCVA) was recorded by manifest refraction and reported in logarithm of the minimum angle of resolution (LogMAR).

Results:

Twelve of the total 15 eyes had a diagnosis of peripheral diffuse lamellar keratitis (DLK) preceding the CTK. The DLK was diagnosed within 24 hours in all cases and the CTK appeared with a mean of 7.4±2.0 days after the laser treatment (range 6 to 12). Mean follow-up was 7 months (range 4 to 11). Preoperatively, mean BSCVA was -0.06±0.05 LogMAR (range -0.1 to 0.0) and mean manifest refraction spherical equivalent (MRSE) was -3.3 ± 2.7 D (range 1.75 to -6.25). On the final visit, the mean MRSE was 0.83 ± 1.04 D (range 2.5 to –0.75) and the mean BSCVA was 0.02 ± 0.09 LogMAR (range -0.1 to 0.2). During the follow up period, the highest postoperative mean hypermetropic shift recorded in spherical equivalent was 1.64 ± 0.79 D (range 2.5 to –0.25 D). In 10 eyes, the mean time to resolution of CTK was 4.6 ± 3.3 months (range 1 to 8 months). Five eyes still had residual signs at the last outpatient visit. Overall, 6 out of the 15 eyes (40%) lost 1 line and 2 eyes (13,3 %) lost 2 lines in BSCVA. However only 3 (20%) achieved worse than 0.0 LogMAR at final follow-up.

Conclusions:

Laser refractive surgery has gained popularity in treating refractive errors and LASIK is the most common technique performed throughout the world. Whilst rare, complications still can occur. CTK is an acute non-inflammatory process following either LASIK or surface ablation surgery. It is characterised by central corneal opacification and stromal tissue loss, leading to significant hyperopic shift. In our case series, 13 eyes out of 15 had a preceding diagnosis of DLK, of various grades. Our series confirms that although a rare entity, CTK can occur in clusters. With such a relatively high number of cases over a short period of time, we hypothesised that aetiology was related to a product or equipment used but, despite extensive investigations to find a common cause we were unable to identify it. However, no patients had a poor visual results. On the contrary with conservative management and observation each patient achieved an excellent visual outcome (all better than 0.2 logMAR) at the last follow-up.

Financial Interest:

NONE