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Because a variety of vision-limiting macular pathologies are detectable only with OCT, this imaging should be performed in all patients undergoing cataract surgery.
By Cheryl Guttman Krader; Reviewed by Steve Charles, MD
Performing optical coherence tomography (OCT) as part of the pre-operative evaluation for all cataract surgery patients represents quality medical care and minimizes the potential for postoperative “visual surprises” leading to unhappy patients.
“Visual surprise is a term I coined to describe poor quality vision despite perfect surgery with a perfect refractive outcome,” Steve Charles, MD, said. “Minimizing the chances of a visual surprise requires OCT because it detects a variety of potentially treatable, vision-limiting macular pathologies that are absolutely invisible with a standard clinical examination.”
Dr. Charles, is founder, Charles Retina Institute, and clinical professor of ophthalmology, University of Tennessee, Memphis.
“Evaluation with OCT is 100% safe, has minimal labor cost, no consumables cost, and provides information that will allow better outcomes and realistic expectations,” Dr. Charles explained. “Recently, there has been an emphasis in cataract surgery on strategies for preventing refractive surprises to avoid patient dissatisfaction. However, surgeons need to avoid leaving patients with a visual surprise. By doing so, surgeons benefit because their patients, families, and the referring doctors will be happier.”
The pathologies that are uniquely identified with OCT include central serous retinopathy, transparent epimacular membranes, vitreomacular schisis, vitreomacular traction syndrome, and early wet age-related macular degeneration with subretinal fluid, a small area of choroidal neovascularization, and no hemorrhage. Although not all of the conditions need to be treated prior to cataract surgery, their presence informs appropriate surgical planning and patient counseling.
For example, optical biometry is mandatory for accurate axial length measurement in an eye with any of these conditions where ultrasound A-scan, which measures from the anterior retinal surface, is prone to error.
These macular conditions represent a relative contraindication to multifocal IOL implantation because the multifocal optics reduce contrast sensitivity. In addition, depending on the pathology that is present, patients may need to be told they will see better after cataract surgery, but they have a condition that will limit them from having perfect vision.
OCT imaging shows a partial thickness macular hole. (Image courtesy of Steve Charles, MD)
The value of OCT for detecting macular pathology depends on the quality of the imaging and proper interpretation, Dr. Charles said. He emphasized that a swept-source or spectral-domain OCT system must be used and that the interpretation should be based on review of all B-scan slices in gray scale.
“Time-domain OCT is obsolete, and do not look at pseudo-color images or 3-dimensional renderings because those software tools hide crucial details,” Dr. Charles pointed out. “In addition, do not let the technician pick a single image to put in the electronic medical record for you to review. OCT is not lab work.
“It is an examination that requires expert interpretation,” he added. “Looking through all of the grayscale images takes no more than 15 seconds… so the objection that OCT adds too much time to the surgeon’s exam and decreases efficiency is a false argument.”
Dr. Charles also observed that some electronic medical record systems allow uploading of a single OCT image into the record. “That capability addresses coding, billing, and compliance issues, but it does not serve to support quality medical care,” he added.
Although it is true that OCT screening for macular pathology will not be reimbursed if the exam is negative, Dr. Charles noted that it does not represent a valid reason for limiting OCT use to patients who are paying extra for a premium IOL procedure.
“Doing OCT on all patients represents good medical practice,” Dr. Charles said. “The cost associated with its use is negligible because it only involves the time spent by the technician performing the imaging and by the physician reviewing the results, both of which are minimal.”
He added that in his retinal practice, almost every patient is evaluated with OCT. The business office staff determines whether or not to bill the insurance companies for the study.
“I have been in practice for 42 years, and it is astounding and embarrassing to think about the number of problems I missed when I was examining patients with complaints about their vision before OCT was available,” Dr. Charles said. “With OCT, I can diagnose diseases that can be treated effectively to provide great outcomes. I am glad to have the information that I can get with OCT because it makes me a better doctor and my patients happier.”
Steve Charles, MD
This article was adapted from a presentation that Dr. Charles delivered at the 2017 American Society of Cataract and Refractive Surgery meeting. Dr. Charles has no relevant financial interests to disclose.