OD News Articles

25th June 2019

Pseudophakic Dysphotopsia–“But your surgery looks perfect!”

Modern cataract surgery provides a high level of vision improvement and patient satisfaction, along with a low rate of complications. However, a small percentage of patients are dissatisfied with their result—despite what may appear to be a perfect outcome and excellent visual acuity. These people are most commonly bothered by dysphotopsia.

 

UNDESIRED VISUAL SYMPTOMS

Pseudophakic dysphotopsia refers to several undesired visual symptoms that can follow routine cataract surgery. These symptoms are subdivided into positive and negative varieties.

 

  • Positive dysphotopsia (PD)
    Visual symptoms of “light play” include shimmering, reflections, streaks, arcs, and halos.

 

 

 

 

  • Negative dysphotopsia (ND)
    A dark shadow or crescent in the temporal field of vision that is sometimes described as a “horse blinder” effect.

 

Dysphotopsia has become the most common cause of patient dissatisfaction following uncomplicated, successful cataract surgery (1). Fortunately, the vast majority of people who complain of these symptoms soon after treatment report they improve or resolve within a few days. A smaller percentage of patients will continue to be bothered by unwanted optical effects for weeks or longer. Regrettably, there is no reliable way to predict who will have persistent troublesome dysphotopsia.

 

WHAT IS THE CAUSE?
  • Positive Dysphotopsia
    The primary cause for PD has been attributed to the square or sharp edge design of modern IOLs(2). High refractive index and surface reflectivity of modern IOLs are also suggested to play a role. Significant dysphotopsia was considered extremely rare with older generation rounded edge PMMA IOLs. However, the IOL industry has moved toward a square edge design to reduce posterior capsular opacification (PCO). Although this was a worthy goal, the square edge has been implicated in an increased incidence of dysphotopsia.
  • Negative Dysphotopsia
    Factors leading to ND include small pupil (3), larger distance between the back of the iris and the front of the IOL, square edge IOL design, anatomical variation of anteriorly extending functional nasal retina, reflection of the anterior capsulotomy edge projected onto the nasal peripheral retina, and a larger angle kappa (angle between the visual axis and pupillary center)(4).
PATIENT MANAGEMENT

So how should we manage patients complaining of dysphotopsia symptoms following uncomplicated cataract surgery?

First, it is essential to rule out other potential causes that can generate similar symptoms. These include:

  • IOL decentration
  • Acute PVD
  • Retinal tear or detachment

Once these are eliminated as factors, it is critical to validate the patient’s early post-operative symptoms and exude a sympathetic tone. Reassure them that other patients commonly observe their symptoms during the early post-op period. They do not represent a threat to vision and almost always subside with time. This strategy will usually lower patients’ anxiety and frustration. Abruptly telling them that there is nothing wrong or advising them to simply ignore it will likely lead to an opposite effect.

In the less common cases where symptoms are persisting and bothersome beyond 4 to 6 weeks, it is appropriate to offer potential remedies. The primary non-surgical approach is to trial dilute pilocarpine or brimonidine to reduce pupil size. This may be helpful for PD but is not expected to assist with ND.

Updating the patient’s spectacles for residual refractive error and addressing any dry eye may be helpful while waiting to see if the dysphotopsia will subside. It is also appropriate to refer the patient back to the surgery center for consideration of a surgical approach.

At PCLI, our preferred surgical strategy is to perform in-the-bag IOL exchange with a different type of lens implant—most commonly a PMMA IOL. In our experience, this usually provides a meaningful improvement for the patient.

In cases of purely ND, another strategy is to move the existing IOL optic anteriorly in front of the rim of the capsulorhexis while keeping the haptics in the bag (reverse optic capture)(5). Ideally, surgical intervention for dysphotopsia should take place in the 3 to 6 month window following cataract surgery. This allows time for the symptoms to potentially resolve on their own while minimizing the risk of capsular damage during IOL exchange due to progressive fibrosis around the haptics.

YAG CAPSULOTOMY

When considering a YAG capsulotomy, it is essential to decipher symptoms consistent with PCO versus symptoms consistent with dysphotopsia as there is the potential for some overlap. Symptoms that arise right after cataract surgery should be suspect for dysphotopsia as opposed to symptoms that develop months or years after cataract surgery, which better correlate with PCO formation.

The distinction is essential because opening the posterior capsule with YAG surgery eliminates the option of IOL exchange for dysphotopsia due to significantly increased risk of capsular damage, vitreous prolapse, cystoid macular edema, and retinal detachment.

CONCLUSION

Although uncommon, persistent pseudophakic dysphotopsia can lead to significant patient dissatisfaction. Recognizing this issue, educating patients, and communicating with the surgery center are important in turning unhappy patients into happy ones.

QUESTIONS

If you have questions, feel free to contact any of our optometric physicians. We’re always happy to help.

REFERENCES
  1. Kinard K, Jarstad A, Olson R. Correlation of visual quality with satisfaction and function in a normal cohort of pseudophakic patients. J Cataract and Refract Surg. 2013;39:590-7
  2. Franchini A, Gallarati BZ, Vaccari E. Computerized analysis of the effects of intraocular lens edge design on the quality of vision in pseudophakic patients. J Cataract Refract Surg. 2003; 29:342-347.
  3. Holladay JT, Zhao H, Reisin CR. Negative dysphotopsia: The enigmatic penumbra. J Cataract Refract Surg. 2012; 38:1251-65.
  4. Holladay JT, Simpson MJ. Negative dysphotopsia: Causes and rationale for prevention and treatment. J Cataract Refract Surg 2017;43:2:263-275.
  5. Masket S., Fram N.R., Cho A., Park I., Pham D. Surgical management of negative dysphotopsia. J Cataract Refract Surg. 2018; 44:6-16
     
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