FDA MDR on ALCON/Summit Apex Plus - pupil size issue
http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/Detail.CFM?MDRFOI__ID=321365
Pt has undergone photorefractive keratectomy (prk) at hosp in a foreign country with a fda approved excimer laser, i. E. The apexplus of the co summit technology. The purpose of the treatment was correction of myopia which was determined as follows: -7. 3 diopters of myopia (d) and -1. 75 d of astigmatism on the right eye and -6. 8 d of myopia and -1. 5 d of astigmatism on the left eye. The treatment was performed with an ablation zone of 6. 5 mm. Up to today, at a distance of almost 5 years from the treatment, pt suffers from halos and glare and complains about bad vision at night. In order to collect more info about the device itself, rptr had a look at the documentation put on the internet and downloaded approval p930034 of 10/25/95, the only one that matched the device description and the date. Inside the documents rptr found some criteria which have to be met in order to ensure that the device is suitable for a certain pt. In the fda letter to summit of 10/20/95 rptr found under restrictions of use that the device is suitable for "moderate nearsightedness (-1.5 to 7.0 diopters when concomitant astigmatism is no greater than 1.5 diopters). ". In addition it is clearly specified as not indicated to correct high myopia (nearsightedness > -7.0 d). So, as mentioned above, the actual values of myopia and astigmatism exceeded the specified ones. As far as it regards the ablation zone rptr found an indication that the device was approved for a 6. 0 mm ablation area, while during the treatment a 6.5 mm diameter was used. So rptr's first question is whether there were amendments to the approval p930034. According to which the corrected values would have been inside an admittable range of new values or was the device used off-label ie outside the indicated limits. Rptr understood from the literature published before procedure date that the problems, pt is reporting, could be due to optical zone edge effects, especially when the pupil is dilated. Moreover i learned from the documentation, put on the internet, that large pupils have to be considered as a risk factor as far as it regards occurrence of glare and halos after refractive surgery. According to a survey, performed on pt in 10/99, the ablation was of good homogenity, it was perfectly centered and it had an usuable optical area of 4 mm on the right eye and of 4.5 mm on the left eye. Thus the dr stated on his report that the reason for the pt's problems has to be the pupillary diameter which is bigger than the treated area (rptr supposes he refers to the usable optical area and not to the abaltion zone). So rptr's second question is whether fda issued some specifications or amendments to approval which deal with long term risks of debilitating symptoms related to the pupillary diameter, its dynamics and the dimensions of the ablation area.