The informed consent for refractive lens exchange must apprise patients about the risks of endophthalmitis and rhegmatogenous retinal detachment. Data on these issues, which are mostly derived from the cataract surgery literature, are reviewed.
New Orleans-Candidates for refractive lens exchange (RLE) are younger than the typical cataract surgery patient. However, published data derived from the cataract surgery population provide the primary basis for characterizing the risks of RLE. Emanuel Rosen, MD, and Kerry D. Solomon, MD, reviewed the topic at the Spotlight on Cataract Symposium held during the American Academy of Ophthalmology annual meeting.
Dr. Rosen noted that postoperative endophthalmitis and rhegmatogenous retinal detachment (RRD) represent the main sight-threatening risks that need to be discussed with patients considering RLE. According to various published reports, the risk of endophthalmitis following cataract surgery ranges from ~1 eye in 3,000 surgeries to ~1 in 1,500 cases. In the recent European Society of Cataract and Refractive Surgeons study of endophthalmitis prophylaxis, however, the incidence varied from a best-case scenario of one in 1,400 eyes in the group that received intracameral cefuroxime to one eye in 300 considering surgeries where the intracameral antibiotic was not used. Dr. Rosen is director, Rosen Eye Clinic, Manchester, England.
"So in terms of the rate of endophthalmitis following RLE, figures of one in 300 cases to one in 1,600 cases would certainly not underestimate the risk," he commented.
Regarding the risk of RRD following crystalline lens extraction and replacement with a pseudophakic IOL, it is first relevant to consider the risk of RRD in the general population. A study by Polkinghorne et al. from New Zealand reported RRD occurs in 1 in 8,500 eyes each year within the general population not having cataract surgery. In another New Zealand study including nearly 1,800 eyes with follow-up to 10 years, however, the rate of RRD was one in 850 eyes per annum, or a tenfold increase compared with unoperated eyes. Results of a population-based study by Erie et al., suggested cataract surgery increased the risk of RRD by fourfold, noted Dr. Rosen.
"Very relevant to the RLE population, Erie and co-workers reported that the risk was increased dramatically to one eye in 200 among patients aged 50 and under, and increased axial length also was associated with an increased risk. Moreover, Erie et al. found the cumulative risk of RRD increased over 20 years. By the end of that interval, 18 eyes in 1,000 had suffered RRD," he said.
Dr. Rosen also cited a study by Ripandelli, et al., that found posterior vitreous detachment (PVD) occurred after cataract surgery in 76% of eyes without preoperative PVD or lattice degeneration, and the rate increased to 87% in eyes with preoperative lattice degeneration but no PVD.
"This is a very relevant risk. Also, eyes with preoperative lattice degeneration and postoperative PVD had a 21% incidence of RRD after cataract surgery, which was significantly higher than the 0.7% rate in eyes without preoperative PVD or lattice degeneration," Dr. Rosen said.
To evaluate the further risk of RRD after RLE, Dr. Rosen and colleagues undertook a review of data from 21 papers published in the ophthalmology literature between 1995 and 2006 combined with a series of 583 eyes operated on at his own surgical center. In the individual studies that included patients undergoing cataract surgery or myopic RLE, the RRD rate varied from 0% to 8%. The mean cumulative rate for the total population of 6,042 eyes was 2.2% or about one in every 50 eyes.
"There are so many potential confounding variables within these studies, however, that it becomes difficult to draw sensible conclusions about the relevance of these data to a pure RLE population," acknowledged Dr. Rosen.
He pointed out that it is also important to consider the outcomes after RRD. Data on this issue were reported by Ranta and Kivela, who evaluated 138 eyes that experienced RRD after uncomplicated extracapsular cataract extraction. Although the retina remained reattached long-term after surgical repair in 91% of eyes, some of those eyes still lost best-corrected vision. Furthermore, the other side of the coin is that the repair surgery failed in 1 of 11 eyes.
"Evidence in the literature suggests that candidates for RLE should be informed that myopic eyes run a much higher risk of RRD. RRD is very unusual after lens removal surgery in hyperopic eyes, but some risk persists for years. The anatomic and functional outcomes after RRD need also to be discussed, and data on risk of postoperative endophthalmitis are very relevant to RLE," concluded Dr. Rosen.