Presbyopic lens exchange for high myopia problematic

Alicante, Spain-While one segment of the ophthalmic community sees presbyopic lens exchange for patients with high myopia as a promising, safe technique leading to good improvements in visual acuity, another segment does not, stating that the risk of retinal detachment and other complications related to the surgery are just too high, according to Jorge L. Alio, MD.

"First, we must consider the clinical environment in which clear lens extraction in patients with high myopia is being performed," Dr. Alio emphasized. "In these patients this is a refractive procedure and no cataract has yet developed. The patients are young or middle-aged beginning in the fifth decade of life. In most cases, the vitreous is still attached. Importantly, these are indeed high-risk eyes in that they have the potential for retinal detachment, glaucoma, and macular disease. And it is well known that they are at risk of visual loss for the remainder of their lives."

Presbyopic lenses implanted to treat high myopia provide good results, with about 90% of the eyes within ±1.0 D of emmetropia. However, an important consideration is that refractive presbyopia can be treated only with multifocal optics and the results are debatable because of issues surrounding contrast sensitivity.

"Refractive lens exchange in high myopia should be considered an effective procedure performed on a high-risk eye. But what is the potential for complications considering the status of the current technology? What is the price we have to pay for presbyopic lens exchange in high myopia?" Dr. Alio asked.

Postoperative complications

Dr. Alio listed a number of potential complications: the development of endophthalmitis, loss of accommodation, posterior capsule opacification (PCO), posterior vitreous detachment, macular disease, and retinal detachment.

"The risk of the development of endophthalmitis following clear lens exchange should be considered to range from 0.1% to 0.29%; however, in complicated cases the incidence can increase to 1%," Dr. Alio reported.

The loss of accommodation after clear lens extraction is, he described, complete and definitive. Patients can have either multifocal IOLs or accommodative IOLs implanted.

"However, we must be aware these IOLs have not yet been reported to be as effective in patients with high myopia and they are unavailable in most countries," he stated.

Another consideration regarding accommodation is that in patients near the age of 40 years who undergo clear lens exchange still retain about 2 D of accommodation in the middle of the fifth decade of life. This will be lost following the clear lens exchange procedure, Dr. Alio pointed out.

PCO develops in 61% to 78% of patients by 7 years after a lens implantation procedure.

"The mean interval for the development of PCO is 48.4 months," he said. Hand in hand with this, retinal detachment following capsulotomy occurs frequently in eyes that are not at high risk, but increases to 8.3% when the axial length exceeds 26 mm.

"This axial length increases the risk of retinal detachment following YAG capsulotomy by a factor of 1.5," he emphasized.

There is also an increased risk of posterior vitreous detachment, according to Dr. Alio. He noted that after the age of 40 years, 42.3% of patients still have partial vitreous attachment.

A number of patients, ranging from 3.2% to 10%, will develop macular disease when the axial length exceeds 26 mm. Women are at increased risk. This general risk, he pointed out, may be increased as the result of cataract surgery or lens exchange.

"Retinal detachment develops in 2.1% to 9.2% in the literature and there is a cumulative rate of at least 1% in these cases. The complications associated with retinal detachment are younger age, incomplete vitreous detachment, YAG laser capsulotomy, longer axial length, a history of retinal detachment in the fellow eye, and peripheral retinal degeneration," he explained.