Article Date: 10/1/2011

Revisiting Dilation
Street Smarts

Revisiting Dilation

By Dan Beck, OD, Leland, N.C.

Within the walls of the optometry schools, the very idea of not dilating a a patient is tantamount to blasphemy. Once in the real world, however, many new ODs may be surprised by the number of eye exams performed without the use of dilating agents. Although a thorough dilated fundus exam is the standard of care, there is a good deal of variation when it comes to meeting that standard. Several variables other than the dilating drops can make or break an accurate retinal evaluation.

Dilated Pupil Size

Many older patients (and patients with diabetes, in particular) dilate poorly. Sometimes, even two rounds of dilating drops don't produce a decent viewing window. By contrast, some younger patients have pupils large enough to obtain good peripheral retinal views without drops or with just the mildest agents.


There is a vast disparity in binocular indirect ophthalmoscopes (BIOs) and condensing lenses used in retinal evaluation. Most of the newer BIOs have small pupil options that allow better views if the patient dilates poorly. Unfortunately, BIOs seem to be the piece of equipment that's last to be upgraded. Many offices stil use indirect ophthalmoscopes that were manufactured when Reagan was still in the White House.

The condensing lens also plays a role. A large number of docs are still exclusively using the same 20D lens they bought in their first week of optometry school. While the 20D is still considered the workhorse lens of the industry, lenses including the 25D, 22 and 30D provide much wider fields of view.

Patient Cooperation

Even when a great dilation is achieved, it doesn't help if the patient won't keep his eyes open. We've all had patients who won't stop twitching or blinking until the BIO is turned down to a level that makes viewing subtle retinal changes next to impossible.

Buy New Stuff

Completing a full retinal exam isn't as easy—and isn't done as often—as the documentation would suggest. While new technologies, such as the optomap (Optos), can help reach that goal, many practices simply cannot afford it. Investing in a newer indirect ophthalmoscope and maybe a new condensing lens would be smart and probably within the budgets of most practices. nOD

Dilating his patients every day, Dr. Beck is a 1993 graduate of the Pennsylvania College of Optometry. You can reach him at

Optometric Management, Issue: October 2011