Posterior vitreous detachment portends risk for retinal detachment after refractive lens exchange

How posterior vitreous detachment before surgery affects retinal detachment rate in myopic eyes will be the objective of a new study in Europe.

Issue: August 25, 2017

Posterior vitreous detachment plays a key role in determining the risk rate for retinal detachment after lens surgery, particularly in highly myopic eyes.

“Detecting the presence of PVD by SD-OCT or ultrasound may be of relevance for the prognosis of RD, particularly in younger high myopic patients undergoing refractive lens exchange,” Oliver Findl, MD, MBA, FEBO, told Ocular Surgery News.

Data on retinal detachment rate after lens surgery are “a real jungle in which you have to fight to try to get through,” he said.

In the general population, the incidence of retinal detachment ranges from 0.006% to 0.018% per year. Pseudophakic retinal detachment is significantly higher, on average 1.17% over 10 years. In patients younger than 50 years of age, the risk increases up to 5.17%.

“In myopic eyes with more than 10 D of myopia, the risk is 0.68% per year. After phacoemulsification, the rate reported by studies varies between 2% and 8%,” Findl said.

A recent study by Tassignon and her group in Antwerp, Belgium, reported a 5-year cumulative retinal detachment incidence of 1.44% in a large cohort of 1,323 eyes implanted with the bag-in-the lens IOL. About two-thirds of the cases were myopic. Other classic risk factors were male gender, younger age and retinal detachment in the fellow eye.

Another study by Alió and co-authors looking at the retinal detachment rate in 439 highly myopic eyes after small-incision phacoemulsification found that most of the retinal detachment cases occur within 5 years of surgery.

Role of vitreous

The anatomic and biochemical changes produced in the vitreous by the operation play a key role in increasing the risk for retinal detachment, and more so in long myopic eyes.

“By replacing the thick crystalline lens with a thin IOL, we increase the posterior segment volume, and the forward motion of the anterior hyaloid exerts a dynamic traction on the vitreous base. There are also changes in vitreous composition, induced by the low inflammation and decrease in hyaluronic acid concentration that follows uncomplicated cataract surgery,” Findl said.

Horseshoe tears caused by posterior vitreous detachment are essentially the trigger for retinal detachment. The average onset age for posterior vitreous detachment is 59 years in phakic emmetropic eyes and 47 years in high myopes, according to a study by Itakura and colleagues.

“The more myopia, the younger the onset age,” Findl said.

After lens surgery, posterior vitreous detachment is a common event, occurring at least partially in about 60% of eyes within 1 month, according to several studies. Patients younger than 70 years of age have double the chance as compared with older patients, and in longer eyes with an axial length of 25 mm or greater, the chance is nearly fivefold higher.

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“There are obviously quite dynamic and extreme changes within these first few weeks after surgery, and again they are more pronounced in the younger age group and in myopic eyes,” Findl said.

Posterior vitreous detachment before surgery

A study by Ripandelli and colleagues showed that posterior vitreous detachment before surgery has a protective effect against retinal detachment after surgery. Patients who already had posterior vitreous detachment preoperatively had a 1.1% retinal detachment risk at 5 years compared with 7.4% in those who did not have preoperative posterior vitreous detachment.

“This study mainly enrolled emmetropic patients. We now want to see how PVD before surgery affects RD rate in myopic eyes,” Findl said.

This will be the objective of a new study funded by the European Society of Cataract and Refractive Surgeons. The multicenter study, which involves 10 sites in five countries in Europe, will recruit 618 myopic patients with axial length of 25 mm or longer. Main outcome will be retinal detachment rate at 3 years and 5 years. Clinical fundoscopy and spectral domain OCT will be used to define whether posterior vitreous detachment is present, with the addition of ultrasound examination in cases where it is unclear.

“Refractive lens exchange is an optional surgery, and we believe that PVD presence before surgery and the chance of PVD after surgery are important parameters to evaluate when making this choice with the patients. It is also important to educate patients about the warning symptoms after surgery because the earlier they come, the better the chance of avoiding retinal detachment,” Findl said. – by Michela Cimberle

References:
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Hikichi T, et al. Ophthalmology. 2004;doi:10.1016/j.ophtha.2004.02.015.
Hilford D, et al. Eye (Lond). 2009;doi:10.1038/eye.2008.273.
Itakura H, et al. Invest Ophthalmol Vis Sci. 2014;doi:10.1167/iovs.13-13496.
Ivastinovic D, et al. Am J Ophthalmol. 2012;doi:10.1016/j.ajo.2011.09.009.
Lois N, et al. Surv Ophthalmol. 2003;doi:10.1016/S0039-6257(03)00083-3.
Mirshahi A, et al. J Cataract Refract Surg. 2009;doi:10.1016/j.jcrs.2009.02.016.
Ripandelli G, et al. Ophthalmology. 2007;doi:10.1016/j.ophtha.2006.08.045.
Rosen E. J Cataract Refract Surg. 2006;doi:10.1016/j.jcrs.2006.03.012.
Russell M, et al. J Cataract Refract Surg. 2006;doi:10.1016/j.jcrs.2005.12.095.
Tassignon MJ, et al. J Cataract Refract Surg. 2015;doi:10.1016/j.jcrs.2015.05.026.

For more information:
Oliver Findl, MD, MBA, FEBO, is head of the department of ophthalmology at Hanusch Hospital and founder and head of the Vienna Institute for Research in Ocular Surgery (VIROS). He can be reached at Department of Ophthalmology, Hanusch Hospital, Heinrich Collin-Straße 30 1140, Vienna, Austria; email: oliver@findl.at.

Disclosure: Findl reports he is a member of the scientific advisory boards of Abbott, Bausch + Lomb and Carl Zeiss Meditec.