LASIK and PRK are equals

Laser assisted in-situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) offer comparable results for the correction of myopia, but LASIK provides faster visual recovery, according to the results of a review published in The Cochrane Database of Systematic Reviews 2006, Issue 2.

Alex Shortt, MD, of the Institute of Ophthalmology, Mater Misericordiae Hospital, Dublin, Ireland and Bruce Allan from Moorfields Eye Hospital, London, UK searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBAS and LILACs for randomized controlled trials that compared PRK and LASIK for the correction of any degree of myopia. They also compiled data on adverse events from prospective consecutive case series in the US FDA trials database. Data was summarized using odds ratio and mean difference. Odds ratios were combined using a random-effects model after testing for heterogeneity.

The review included six randomized trials involving a total of 417 eyes, of which 216 were treated with LASIK and 201 with PRK. The authors found that LASIK offers a faster visual recovery than PRK but the effectiveness of the two procedures is comparable. There was some evidence that LASIK may be less likely to result in the loss of best spectacle corrected visual acuity.

LASIK satisfies most

Kuang-mon Ashley Tuan from Visx, Santa Clara, California, USA, performed a retrospective analysis of clinical study results from 274 myopic-astigmatic eyes treated at six sites with wavefront guided LASIK. Thorough evaluations of vision and ocular health were conducted prior to treatment and for six months postoperatively. VA and contrast sensitivity were measured and questionnaires distributed. Reponses to the questionnaire were compared with clinical measurements.

Patients were more expressive about visual decline than visual improvement and perception of changes in vision appeared to be related to mesopic contrast sensitivity and mesopic contrast sensitivity under glare. Mesopic pupil diameter was not a major predictor of patient satisfaction. Spectacle wearers were less satisfied with their postoperative vision than contact lens wearers and men were more likely than woman to report visual symptoms and complain about night vision despite their changes being the same.

The author concluded that most patients are as satisfied or more satisfied with their postoperative uncorrected VA than with their preoperative BCVA and, by continuing to minimize postoperative refractive error through the use of nomograms, and improved technology, complaints such as night glare and halos could be virtually eliminated. The study also noted that subjective experience affected overall satisfaction with results and that this may be reduced by educating patients to have realistic expectations before undergoing the surgery.

LASIK could induce diplopia

Patients with high anisometropia and a weak sensorial state who undergo refractive surgery may be at risk of postoperative diplopia, according to a study published in the May 2006 issue of the Journal of Refractive Surgery.

Luca Buzzonetti, MD and colleagues from the Institute of Ophthalmology, Catholic University, Rome, Italy, examined 26 eyes of 16 patients, each of whom had high myopic anisometropia. Pre- and postoperative ophthalmologic and orthoptic examinations were performed and preoperative orthoptic examinations were carried out with glasses and contact lenses. A total of 22 eyes of 13 patients received uncomplicated LASIK with the second eye being treated two weeks after the first. Subjects were examined one and seven days postsurgery and then at one, three, six and twelve months.

Thirteen patients achieved good results at the red glass bar test (RGB) and underwent LASIK without postoperative diplopia; four of these demonstrated an improvement of the sensorial assessment. Three patients did not undergo surgery because of diplopia with RGB values of <4 to 5. LASIK induced diplopia in the suppressed eye of just one patient but this disappeared after surgery of the fixating eye.