Patients' Preference Regarding Laser Photocoagulation or Cryoretinopexy for the Treatment of Retinal Pathology

Abstract

Purpose:

High-risk peripheral retinal pathology can be prophylactically treated with both laser photocoagulation (laser) and cryoretinopexy (cryopexy). We sought to identify a possible preference by patients toward one modality and any underlying association.

Methods:

A single-center survey was conducted of patients with peripheral retinal pathology who received both laser and cryopexy at Associated Retinal Consultants (Royal Oak, Michigan). The main outcome measure was the preferred treatment modality.

Results:

Patients reported more pain after cryopexy (46%) than laser (11%). Most patients felt it was easier to recover from laser (52%) than cryopexy (13%). Overall, patients preferred laser (60%) to cryopexy (25%), with a minority (15%) having no preference. There was a negative relationship between a patient’s likelihood of preferring cryopexy and the number of applications (P = .009).

Conclusions:

Most patients preferred laser (60%) to cryopexy. If cryopexy is performed, minimizing the number of freezes may improve the patient’s experience and recovery.

Introduction

Retinal tears are typically horseshoe-shaped or round operculated breaks in the neurosensory retina and are most often caused by traction from strands of vitreous. Other retinal abnormalities, including atrophic holes and degenerative lattice, can occur without vitreous traction. If left untreated, these retinal defects may lead to a retinal detachment. ^1,2 Options for treating peripheral retinal breaks to mitigate retinal detachment progression include laser photocoagulation (laser) and/or cryoretinopexy (cryopexy). Both have proven to be efficacious and safe in practice. ^{3 -6}

The decision as to which treatment is most appropriate is typically based on a variety of factors such as pathology location, the patient’s cooperation, access to equipment, presence of subretinal fluid, and the physician’s comfort with the procedure. ⁷ The patient’s experience with each modality can be different given the variability of machinery, positioning, lighting, anesthesia techniques, duration of treatment, and recovery. To the best of our knowledge, there have been no studies evaluating patients’ preferences between laser or cryopexy for the in-office treatment of peripheral retinal pathology.

The purpose of this study was to retrospectively assess the experience of those who underwent both laser and cryopexy for one or multiple peripheral retinal pathologies. We chose to survey patients who underwent both treatment modalities because this patient population is unique in their ability to compare one treatment experience with the other. There are various reasons why these patients underwent both treatment modalities, with the final recommendation based on the physician’s determination of the pathology location, configuration, associated characteristics, previous treatment success, and likelihood of successful treatment. These results may help tailor the treatment of peripheral retinal breaks to specific clinical scenarios to improve and optimize the patient experience.

Methods

Study Design

This study was a single-center retrospective patient-preference survey at Associated Retinal Consultants (Royal Oak, Michigan). Current Procedural Terminology (CPT) codes were used to identify patients who previously underwent in-office (outpatient) laser and cryopexy for peripheral retinal pathology except for panretinal photocoagulation from January 1, 2013, to May 31, 2020. Medical records were manually reviewed to confirm that patients underwent both laser and cryopexy and that the treatments were performed in the study period.

Survey/Data Collection

The identified patients were invited to participate in a phone-based survey. The 12-question survey can be viewed in Figure 1. Details of the patients’ age and sex; the pathology location and laterality; laser type, spot size, and power; number of laser spots; anesthesia type; number of cryopexy applications; whether treatment was in the same eye or fellow eye; and time between treatments were recorded. The provider chose the anesthesia type based on the pathology location and the patient’s comfort. The laser photocoagulation treatments were completed using either the argon laser indirect ophthalmoscope (LIO; IRIDEX OcuLight Symphony) or the PASCAL (patterned scanning laser) photocoagulator (Topcon). Cryopexy was performed using a liquid nitrogen mechanism (Mira Ophthalmic Cryo), and anesthesia was either topical or subconjunctival 2% lidocaine.

Figure 1.

Sample survey. N indicates no; Y, yes.

The primary outcome measure was the patient’s preferred treatment with either laser, cryopexy, or no preference. Statistical analysis was performed using JASP (University of Amsterdam). Chi-square testing was used to compare the categorical variables with a patient’s preference, and logistic regression was used to compare the continuous variables with a patient’s preference. Patients who had no preference between laser or cryopexy were not included in the statistical analysis. A P value less than .05 was considered statistically significant.

Results

A total of 329 unique patients were identified with CPT codes for both laser and cryopexy performed as an outpatient. Of these, 298 were confirmed to have undergone both treatment modalities in the predetermined time frame. All 298 patients were subsequently called, with 108 patients responding to the survey (36.2%). Of the 108 responses, 8 were excluded because they could not adequately remember either the laser or cryopexy treatment. Therefore, 100 patients ultimately met inclusion criteria.

The mean patient age was 60 years (range, 13-84 years), with 58% being male. The location of the treated break for the laser was most commonly in the superior quadrant (51%), followed by temporal (21%), inferior (16%), and nasal (11%) areas. The majority received only topical anesthesia (78%), followed by subconjunctival (12%) and unknown anesthesia (10%). LIO was used in 60% of cases, followed by PASCAL (31%) and unknown device (9%). The mean laser power was 335 mW (range, 100-750 mW), and the mean number of laser spots was 335 (range, 30-2300).

Location of the pathology for cryopexy was most commonly in the superior quadrant (45%), followed by inferior (21%), temporal (20%), and nasal (10%) areas. The majority (88%) received subconjunctival lidocaine. The average number of freezes was 3.6 applications (range, 1-17). Most patients (71%) had both treatments performed on the same eye. The average number of days between each treatment was 196 days (range, 0-1870 days), with 15 patients undergoing both the same day.

Patients reported more significant anxiety during the laser procedure (40%) as compared with cryopexy (24%) (Figure 2A). Their recollection of pain experienced during the procedure was similar, with 31% of patients reporting more pain with laser vs 37% of patients reporting more pain with cryopexy. However, only 11% of patients reported experiencing more pain after treatment with laser vs 46% of patients following cryopexy. Of note, 23% of patients had no pain during either procedure, and 34% had no pain after either procedure (Figure 2B).

Figure 2.

(A) Patients’ relative anxiety before and during laser and cryopexy (cryo). (B) Patients’ relative pain during and after laser and cryopexy.

The incidence of adverse reactions after the procedure, including double vision, blurred vision, eye redness, eye swelling, and itching/discomfort, was higher for cryopexy for all symptoms except blurred vision (Figure 3).

Figure 3.

Incidence of postprocedure adverse events for laser and cryopexy. Patients who received both cryopexy and laser the same day were excluded.

Slightly more patients (40%) perceived the laser to have taken longer than cryopexy (31%) (Figure 4A). The majority felt it was easier to recover from the laser (52%), with only 13% endorsing cryopexy as having an easier recovery (Figure 4B). Overall, 60% preferred laser, 25% preferred cryopexy, and 15% expressed no preference (Figure 4C).

Figure 4.

(A) Patients’ perception as to which procedure was longer. (B) Patients’ relative ease of recovery, excluding those who had both procedures the same day. (C) Overall patients’ preference. Cryo indicates cryopexy.

There was no significant association with patient age (P = .51), sex (P = .50), LIO vs PASCAL (P = .45), same or fellow eye (P = .41), order of procedure (P = .15), laser power (P = .83), number of laser spots (P = .59), or the time between treatments (P = .40) and the patient’s preference of laser or cryopexy. Patients who had undergone subconjunctival lidocaine compared with topical anesthesia for laser were more likely to prefer cryopexy than laser (P = .012). There was a negative association between a patient’s likelihood of preferring cryopexy and the number of cryopexy applications (P = .009) (Figure 5). Selective patients’ reasons for preferring laser or cryopexy are shown in Table 1.

Figure 5.

Estimate plot from logistic regression demonstrating the probability of preferring cryopexy based on the number of freezes. Gray shading is 95% CI.

Table 1.

Why Patients Preferred Laser or Cryopexy: Selective Responses.

Laser	Cryopexy
“Less involved, no numbing, no post-op headache.”	“Freezing was shorter and more efficient.”
“Less painful.”	“Laser caused more anxiety during the procedure.”
“Idea of freezing made me uncomfortable.”	“Takes less time and less painful; didn’t seem to go on forever.”
“After the laser was done, the pain didn’t last as long.”	“The freezing didn’t come with so many warnings to hold still.”
“No brain freeze.”	“Felt it was more effective.”
“Even if the laser was more painful during the procedure, it was still better post procedure.”	“Less invasive, less time, less pain.”

Abbreviation: post-op, postoperative.

If patients who received both laser and cryopexy the same day (15 patients) were removed from the analysis, there were no differences in outcomes. The laser was preferred by 55 patients (65%), cryopexy by 18 patients (21%), and no preference for 12 (14%). Additionally, the only factors that were significantly associated with preference were subconjunctival lidocaine as a negative predictor of laser preference (P = .016) and the number of cryopexy treatments as a negative predictor of cryopexy preference (P = .011).

Conclusions

Cryoretinopexy and laser photocoagulation are the conventional nonsurgical methods to treat peripheral retinal pathology. The safety ⁸ and efficacy of these treatments have been demonstrated to be comparable, ⁹ with each having certain advantages. The literature highlights each treatment’s benefits while demonstrating that neither has superior long-term visual outcomes, especially during scleral buckle surgery. ¹⁰ Factors for the physician to consider when choosing a treatment include treatment location, visibility, ¹¹ size of the retinal tear, and the patient’s ability to cooperate. The physician’s comfort, skill, and level of experience influence the outcomes, as evidenced by the finding that 24% of lasers performed by trainees required a subsequent treatment. ¹²

There are several studies in the literature about patients’ treatment preference. Mason et al ¹³ reported that patients with diabetic macular edema had no preference regarding laser vs intravitreal injections but preferred aggressive treatment and were unwilling to sacrifice vision for fewer visits. Additionally, Mahajan et al found that most patients preferred bilateral injections of antivascular endothelial growth factor agents the same day. ¹⁴ However, to date, there has not been any study to our knowledge that investigates whether patients prefer laser or cryopexy for treatment of peripheral retinal pathology.

Laser photocoagulation typically requires topical anesthesia for the patient to tolerate contact lens placement if a slitlamp laser is used. The laser’s brightness during treatment application can be a source of patient discomfort, as well as the laser application itself depending on the power of the laser, number of shots, and proximity to the long posterior ciliary nerves. Notably, a patient’s pain threshold is highly correlated with successful laser therapy, particularly with panretinal photocoagulation. ¹⁵ Because of this, pharmaceutical adjuvants have been used preemptively to minimize pain and thus improve efficacy. ^{16 -18} Although there was no association between laser type and patients’ preference in the present study, the PASCAL laser has been used successfully to treat proliferative retinopathy with acceptable pain scores. ¹⁹ In the present study, patients reported less pain (see Figure 2B) and an easier recovery (see Figure 4B) with laser, even though laser was associated with more anxiety (see Figure 2A) and a longer interval of perceived treatment (see Figure 4A and Table 1).

Cryopexy is typically performed with subconjunctival anesthesia followed by the application of a nitrogen-cooled probe to the conjunctival surface of the globe. Inadequate anesthesia renders the procedure quite uncomfortable. As our results indicate, patients reported a similar pain experience with laser (31%) and cryopexy (37%) during the procedure. However, more patients (46%) experienced more pain following cryopexy than laser (11%). Based on patients’ preference, the incidence of adverse events after cryopexy (see Figure 3), and verbal responses (see Table 1), the primary drawback to cryopexy is the more difficult and protracted recovery. The recovery/preference is mitigated by fewer cryopexy applications (see Figure 5). Perhaps if the retinal break is amenable to treatment with cryopexy using 2 or fewer applications, like a smaller tear or hole, the patient may be more likely to prefer cryopexy over laser.

The anesthetic choice seemed to play an essential role in patients’ experience, particularly with laser. Surprisingly, patients who underwent subconjunctival lidocaine for laser therapy were significantly more likely to prefer cryopexy (P = .012). It is possible that those patients that received subconjunctival anesthetic for laser presented with a retinal break that was more difficult to treat and required longer treatment times, and thus they had a more negative experience. Additionally, patients may have been more bothered by the recovery from subconjunctival lidocaine because of the chemosis and possible corneal epithelial decompensation.

A prospective randomized trial with data collection at controlled intervals after treatment may better address this question; however, it is not practical to intentionally subject patients to both treatment modalities, nor can a clinician predict which patient will develop subsequent retinal breaks that require further treatment. The benefit of this study is that it included only patients who had underwent treatment with both modalities and allowed a direct patient comparison between the 2 methods.

Nevertheless, there are several limitations to the present study. First, the response rate was only 36.2%, although this is consistent with other telephone-based ophthalmologic surveys. ¹³ Second, this survey relied on patients’ recollection, with varying intervals between treatment and the survey introducing potential recall bias. We attempted to mitigate the recall bias by confirming that the patient had a clear memory of both treatment modalities and excluded those who were not confident. Additionally, the order of treatment was not associated with patients’ preference, indicating that patients were not preferring their first or their last treatment merely because of the timing of the treatments. Finally, there was no way to control provider-specific techniques and rapport, which could modulate the patient’s experience.

In conclusion, among patients who received both laser and cryopexy for the treatment of peripheral retinal pathology, the perception was that laser (40%) took longer than cryopexy (31%) but was easier to recover from (laser 52% vs cryopexy 13%). Overall, most patients (60%) preferred laser to cryopexy (25%). Subconjunctival anesthesia was less preferred to topical anesthesia for laser procedures. If cryopexy is to be performed, minimizing the number of freezes may improve the patient’s experience and recovery. As always, the physician’s comfort level with performing each treatment modality when a patient presents with a retinal pathology is of the utmost importance in ensuring successful treatment and a comfortable experience for the patient.