Patients with the highest risk for developing CRVO

26 April 2013
Posted in Pearls in Ophthalmology

By Brooke Strickland

This study was completed in order to find out the risk factors associated with central retinal vein occlusion (CRVO) among patients of different gender and varying ethnicity.

To find candidates, insurance billing codes were used to find individuals that had recently been diagnosed with CRVO. Participants were 55 years old or younger.

The results revealed that there were several risk factors for CRVO such as glaucoma and hypertension. Other defined variables included: male gender, black race, peripheral artery disease, hypercoagulable state, stroke, and complicated diabetic macular edema. Blacks had a 58% increased risk of CRVO when compared to whites and women had a 25% decreased risk of CRVO compared to men. Stroke increased the risk by 44% and hypercoagulable state had a 145% increased CRVO risk. The study also provided new answers on previously inconsistent findings on the link to CRVO and people with end-organ damage from hypertension or diabetes mellitus. Individuals with damage from hypertension had a 92% increased risk and those with diabetes mellitus had a 53% increased risk of CRVO. (1)

What to take away from this study: Vascular diseases show increased risk for developing CRVO. In addition, the black race also has higher risk for CRVO. There is also a clearer explanation with consistent results for linking CRVO development to diabetes mellitus and hypertension damage. Using this information, doctors can better identify patients with the highest risk for CRVO.

Source:
Stem, Maxwell, S., MD, Talwar, Nidhi, MA, Comer, Grant, M., MD, MS, Stein, Joshua, D., MD, MS. "A Longitudinal Analysis of Risk Factors Associated with Central Vein Occlusion." Ophthalmology. Volume 120, Issue 2, Pages 362-370, February 2013. Accessed April 25, 2013. http://www.aaojournal.org/article/S0161-6420%2812%2900743-9/abstract

Evaluating calibrated force gauge in clear corneal cataract surgery

26 April 2013
Posted in Pearls in Ophthalmology

By Brooke Strickland

This study was published by the Journal of Cataract & Refractive Surgery and was conducted at three private practice study sites. A calibrated force gauge was used on healthy patients during cataract surgery to apply measured and calculable amounts of force to the eye. The first study showed the alteration in IOP during 1 oz of external force – this is approximately the same amount of force exerted when rubbing the eye. For the other studies, the force gauge (also with 1 oz of external force) was used to evaluate the amount of leakage from clear corneal incisions that were exposed to sutures or stromal hydration. There were no complications that arose during these studies.

The first study’s results: the mean IOP rose from a baseline of 17.49mm Hg to 43.44 mm Hg. The second study showed a leak rate of 67% for the main incision. The overall leak rate for the third study (sutures) using up to 1.00 oz of force was a little over 23%. (1)

What to take away from this study: 1 oz of force is a realistic measure of what a patient may feel when rubbing the eye. Following clear corneal cataract surgery, if a patient rubs their eye with this amount of force for three seconds, there is an increased chance of wound leakage.

Source:
Masket, Samuel, MD., Hovanesian, John, MD., Raizman, Michael, MD., Wee, Daniel, MD., Fram, Nicole, MD. "Use of calibrated force gauge in clear corneal cataract surgery to quantify point-pressure manipulation." Journal of Cataract & Refractive Surgery. Volume 39, Issue 4, Pages 511-518. April 2013.  Accessed April 23, 2013. http://www.jcrsjournal.org/article/S0886-3350%2812%2901664-1/abstract

Pupil Diameter and Efficiency of Aspheric IOL

19 April 2013
Posted in Pearls in Ophthalmology

By Brooke Strickland

Patients that have smaller pupil diameters won’t see much benefit from the implantation of aspheric IOLs, says a new study published by the American Journal of Ophthalmology. Researchers measured pupil diameter on 86 patients (169 eyes). Then, based on the measurement, researchers looked to see what the effects were of spherical aberration correction by aspheric IOLs.

This was a cross-sectional study that separated patients into two groups. One group was implanted with the HOYA AF-1 NY-60 IOL and the other group with the Tecnis ZCB00 1-piece IOL. The outcome showed that for individuals with pupil diameters smaller than 3.4 mm (in the Tecnis group) and 3.7 mm (in the HOYA group), the spherical aberration correction with these specific IOLs was ineffective.

Aspheric IOLs were designed to help minimize spherical aberration, and with the results of this study, physicians will be able to measure the pupil and more effectively determine if a patient’s pupil size is too small to see real results after implantation of the lens.

Youngub Eom, Eunjoo Yoo, Su-Yeon, Kang, Hyo-Myung Kim, Jong-Suk Song. "Change in Efficiency of Aspheric Intraocular Lenses Based on Pupil Diameter." American Journal of Ophthalmology. Volume 155, Issue 3, Pages 492-498 e2, March 2013. Accessed April 9, 2013. http://www.ajo.com/article/S0002-9394%2812%2900762-3/abstract