ECTASIA

While ectasia is one of the most devastating complications that can occur following LASIK or PRK, it can now be treated very successfully and good visual outcomes can be achieved in most cases, delegates attending the XXXVI United Kingdom & Ireland Society of Cataract & Refractive Surgeons (UKISCRS) Annual Congress heard. Jan Venter MD emphasised that the occurrence of post-LASIK ectasia, could be reduced with careful preoperative and surgical management. Rigorous patient screening and selection is vital in reducing the development of ectasia. Avoiding enhancements on topographically suspicious eyes, performing surface ablation where appropriate and using phakic IOLs when indicated also help decrease the risks.

[caption id='attachment_5196' align='aligncenter' width='600'] Pre and post intacs[/caption]

“Ectasia can be slow to develop but early diagnosis is important to achieve the best outcomes,†Dr Venter stressed. Warning signs of ectasia include increasing myopia, irregular astigmatism, loss of uncorrected visual acuity, often loss of bestcorrected visual acuity, and progressive corneal steepening, usually inferior, following LASIK.

Explaining his ectasia management advice, Dr Venter presented Optical Express Centre data on 205,285 patients (402, 583 eyes) who had undergone various laser vision correction options between 2007 and 2011. During standard follow-up, ectasia was detected in 58 patients.

The patients who developed ectasia were more likely to be younger than the cohort’s average age (31.1 years versus 38.2 years), to be male, to have a higher preoperative sphere and rates of astigmatism, as well as thinner corneas. The average time to the development of ectasia was 24.5 months though its presentation varied from four to 55 months.

All 58 patients with ectasia received corneal crosslinking according to the Dresden protocol, Dr Venter reported. After waiting for 12 months minimum to ensure stability of the topography and refraction, there were no notable improvements in BCVA and decisions on treating the residual refractive error were taken. Nine eyes did not have any further refractive surgical treatment, with seven of these cases choosing glasses, one a rigid gas permeable contact lens, while one received a lamellar graft.

If the remaining ectasia patients had irregular astigmatism with poor BCVA, they received Intacs. One segment was implanted on the steepest corneal meridian according to the topographic image, with a corneal thickness of more than 400 microns at the site of implantation, aiming at maximal corneal flattening. Two segments were implanted whenever myopic refraction was present.

The remaining ectasia cases had satisfactory BCVA and received either PRK if the predicted ablation depth to correct the remaining refraction was less than 50 microns, while the remaining 16 cases received phakic IOLs as the predicted ablation depth was more than 50 microns.

Following treatment, 88 per cent of these eyes achieved a BCVA of 6/7.5 or better, while 84 per cent had 6/12 or better UCVA, though one eye needed a second corneal collagen crosslinking (CXL) treatment.