Though people who are highly nearsighted have a greater risk of a developing a detached retina than the general population, cataract surgery doesn’t add to that risk.
That’s the finding of a large-scale study presented at the World Ophthalmology Congress held last month in Berlin.
Irmingard Neuhann, MD, who practices at Tuebingen University Eye Hospital in Germany, reported the results of a retrospective study of 1,519 consecutive patients with high myopia that underwent modern phacoemulsification cataract surgery. The surgery was performed on a total of 2,356 eyes that had an axial length greater than 27 millimeters.
Axial length is the distance between the front surface of the eye (cornea) and the back of the eye (retina), usually measured in millimeters (mm).
A normal adult eye typically has an axial length of approximately 24 mm. Eyes with axial length greater than 24 mm usually are nearsighted, and each additional millimeter corresponds to approximately -2.50 diopter (D) of myopia. Therefore, an axial length greater than 27 mm typically corresponds to myopia of -7.50 D or more.
The incidence of retinal detachment following cataract surgery among the eyes in the study was approximately 2 percent, according to Dr. Neuhann. The patients were followed for a period of 2 years.
Though this rate is higher than the rate of detached retina among the general population, no large study has ever demonstrated that this rate is different than that of spontaneous retinal detachment in nearsighted individuals with eyes of comparable axial length, she said.
High myopia associated with increased axial length of the eye is believed to be a risk factor for retinal detachment because, as the eye elongates during development, the peripheral retina becomes thinner and more fragile in these longer-than-normal eyes.
[Resource: Cataract surgery not a risk factor for retinal detachment in highly myopic eyes, study says. Published online June 8, 2010 on Ocular Surgery News website.]
Tags: detached retina, myopia, retinal detachment