New preventative approach for negative dysphotopsia

Modified "C" Haptic Intraocular Lens Orientation and Negative Dysphotopsia

Phacoemulsification is the standard of care in cataract surgery in the developed world, with patients having high expectations regarding visual results. Postoperative dissatisfaction due to negative dysphotopsia (ND) ranges from rare to very frequent; its etiology is unclear, and it affects postoperative satisfaction. Since one of the most frequently used strategies to avoid ND is related to intraocular lens (IOL) haptic orientation, we conducted a prospective interventional study that enrolled 197 patients who underwent standard phacoemulsification. All patients had a one-piece hydrophobic acrylic IOL implanted; in one group, the haptics were placed in any meridional axis except inferotemporal (IT) meridians, and in the other group, the IOL was implanted with the haptics in an IT position. Our results showed no statistically significant differences between groups when analyzing the correlation between the position of IOL haptics and the presence of ND in week one and month one. Also, pupillary diameter showed no statistically significant differences between patients with or without ND. Despite some studies claiming that haptic orientation prevents ND, we found that haptic orientation does not correlate with ND incidence and that ND decreases from day 1 to month 1. Our results support previous findings on the decrease in ND over time and that haptic orientation should not be considered an intraoperative strategy to avoid this unwanted phenomenon.

Evaluation of a new device to treat negative dysphotopsia

PURPOSE

To evaluate the efficacy and safety of Negative Dysphotopsia (ND) Ring implantation for treating and preventing ND.

SETTING

Multicentric tertiary eye hospitals.

DESIGN

Prospective interventional cohort study.

METHODS

22 patients with ND were enrolled. Eyes with other ocular structural pathologies (corneal, macular, optic nerve head, retinal, neuro-ophthalmological) were excluded. In 15 eyes, the ring was implanted to treat ND (therapeutic group), and in 7 eyes, it was implanted during cataract surgery of the fellow eye as a prophylactic measure (prophylactic group) to prevent the occurrence of ND. Preoperative evaluation included video recording of the patients' complaints aside complete eye examination. Postoperatively, patients were interviewed to confirm resolution of complaints related to ND. The intraoperative difficulties and postoperative adverse events were recorded. A minimum follow-up of 1 year was completed for all eyes.

RESULTS

In the therapeutic group, 14 of 15 eyes (93.3%) patients reported complete resolution of ND on the first postoperative day while 1 patient reported persistence of a smaller and lighter temporal shadow. No ND was reported by any patient in any of the 7 eyes treated prophylactically. No significant adverse intraoperative event was recorded; however, vitreous upthrust was noted in 2 of 22 eyes (9.0%). No permanent drop in visual acuity was recorded in the therapeutic group.

CONCLUSIONS

ND Ring implantation was an easy, safe, and effective approach for both treating and preventing ND.

Dysphotopsias or Unwanted Visual Phenomena after Cataract Surgery

Dysphotopsias are unwanted visual phenomena that occur after cataract surgery. They represent some of the most common reasons for patient dissatisfaction after uncomplicated surgery for cataract phacoemulsification with in-the-bag intraocular lens (IOL) implantation. Depending on the form of the optical phenomenon and the effect it poses on vision, dysphotopsias are divided into positive and negative type. Positive dysphotopsias are usually described by patients as glare, light streaks, starbursts, light arcs, rings, haloes, or flashes of light. Negative dysphotopsias are manifested as an arc-shaped shadow or line usually located in the temporal part of the visual field, similar to a temporal scotoma. In addition to their different clinical manifestations, positive and negative dysphotopsia also have different risk factors. Even though up to 67% of patients may experience positive dysphotopsia immediately after surgery, only 2.2% of the cases have persistent symptoms up to a year postoperatively. Surgical intervention may be indicated in 0.07% of cases. The incidence of negative dysphotopsias is up to 26% of all patients; however, by one year postoperatively, the symptoms usually persist in 0.13 to 3% of patients. For both types of dysphotopsia, preoperative patients' education, accurate preoperative diagnostics, and use of an appropriate IOL design and material is mandatory. Despite all these measures, dysphotopsias may occur, and when noninvasive measures fail to improve symptoms, a surgical approach may be considered.

Effect of anatomical differences and intraocular lens design on negative dysphotopsia

PURPOSE

To assess the effect of ocular anatomy and intraocular lens (IOL) design on negative dysphotopsia (ND).

SETTING

Department of Ophthalmology, Leiden University Medical Center, Leiden, the Netherlands.

DESIGN

Ray-tracing study based on clinical data.

METHODS

Ray-tracing simulations were performed to assess the effect of anatomical differences and differences in IOL design on the peripheral retinal illumination. To that end, eye models that incorporate clinically measured anatomical differences between eyes of patients with ND and eyes of pseudophakic controls were created. The anatomical differences included pupil size, pupil centration, and iris tilt. The simulations were performed with different IOL designs, including a simple biconvex IOL design and a more complex clinical IOL design with a convex-concave anterior surface. Both IOL designs were analyzed using a clear edge and a frosted edge. As ND is generally considered to be caused by a discontinuity in peripheral retinal illumination, this illumination profile was determined for each eye model and the severity of the discontinuity was compared between eye models.

RESULTS

The peripheral retinal illumination consistently showed a more severe discontinuity in illumination with ND-specific anatomy. This difference was the least pronounced, 8%, with the frosted edge clinical IOL and the most pronounced, 18%, with the clear edge biconvex IOL.

CONCLUSIONS

These results show that small differences in the ocular anatomy or IOL design affect the peripheral retinal illumination. Therewith, they can increase the severity of ND by up to 18%.

Randomized Controlled Trial of IOL Orientation for Dysphotopsia

PURPOSE

To evaluate whether orientation of the optic-haptic junction of an intraocular lens (IOL) during cataract surgery could decrease the incidence and/or severity of positive and negative dysphotopsia.

DESIGN

Prospective, randomized controlled trial.

METHODS

163 patients (326 eyes) in a private practice scheduled to have bilateral implantation of a Tecnis monofocal IOL (ZCB00) (Johnson & Johnson Vision, Santa Ana, CA) were randomly assigned to have the optic-haptic junction positioned vertically, horizontally, superonasally or inferonasally. Patients with known visual field defects or best corrected vision less than 20/80 were excluded. Patients were surveyed for positive and negative dysphotopsia symptoms at 1 week and 4-6 weeks after surgery. Patients were blinded to the orientation while researchers were not. Data was analyzed to compare the differences in positive and negative dysphotopsia incidence and severity.

RESULTS

IOL oriented vertically in 82 eyes (25.2%), horizontally in 72 eyes (22.1%), superonasally in 94 eyes (28.8%), and inferonasally in 78 eyes (23.9%). Significant difference noted between orientations in incidence of negative dysphotopsia at 1 week postoperatively (p = 0.019) and 4-6 weeks postoperatively (p = 0.002). Patients in the superonasal group had the worst outcome at both time periods, and the horizontal group had the best outcome at 4-6 weeks. No differences were noted for positive dysphotopsia incidence or severity.

CONCLUSIONS

The orientation of the optic-haptic junction of a monofocal IOL was significantly associated with incidence of negative dysphotopsia after surgery, with the horizontal orientation performing best at 4-6 weeks.

Effect of a 7.0 mm intraocular lens optic on peripheral retinal illumination with implications for negative dysphotopsia

PURPOSE

To use optical modeling to compare a 6.0 mm and 7.0 mm intraocular lens (IOL) optic diameters on peripheral retinal illumination with implications for negative dysphotopsia.

SETTING

Mayo Clinic, Rochester, Minnesota, and Simpson Optics LLC, Arlington, Texas.

DESIGN

Model eye.

METHODS

Ray-tracing software was used to simulate retinal illumination from an extended light source for a pseudophakic eye with in-the-bag biconvex IOLs (refractive index [n] = 1.46 and 1.55) and a 2.5 mm pupil. Ray-tracing diagrams and simulated retina illumination profiles were compared using the 6.0 mm and 7.0 mm optic diameter IOLs. Retinal locations were scaled to relative visual angles from 70 to 110 degrees horizontally.

RESULTS

A 7.0 mm optic (n = 1.46) expands the image field by 2.8 degrees compared with a 6.0 mm optic. High-angle input light misses a 7.0 mm optic at a larger visual angle than a 6.0 mm optic, shifting illumination of the peripheral retina by this light anteriorly by 5.6 degrees. Consequently, a region of nonilluminated peripheral nasal retina is enlarged and shifted peripherally using a 7.0 mm optic (visual angle, 86.3 to 96.3 degrees) compared with a 6.0 mm optic (visual angle, 83.5 to 90.7 degrees). Similar illumination changes were seen modeling a 1.55 n IOL.

CONCLUSIONS

A narrow dark region in the nasal retina when using a 6.0 mm optic is changed to a broader, more peripheral dark region when using a 7.0 mm optic. An extended, more peripheral dark nasal region may make a temporal shadow less bothersome and explain lower negative dysphotopsia rates using a 7.0 mm optic.

Comparison of Visual Outcomes and Patient Satisfaction Following Cataract Surgery with Two Monofocal Intraocular Lenses: Clareon® vs AcrySof® IQ Monofocal

Aim:

This study aimed to compare the performance of two monofocal Intraocular Lenses (IOL) platforms.

Background:

The Clareon® Intraocular Lens (IOL) is a relatively new monofocal lens platform designed to improve postoperative results compared to other monofocal platforms.

Objective:

This study aimed to assess and compare the visual and refractive outcomes, and incidence of YAG capsulotomy of the Clareon® IOL and a standard non-preloaded AcrySof® monofocal IOL following contralateral implantation in patients undergoing cataract surgery.

Methods:

A total of 20 patients (40 eyes; 12 female, average age 72.8±6.4 years) who had undergone contralateral implantation of an AcrySof® IQ monofocal lens (SN60WF or SN6AT; Alcon; Texas, USA) and a Clareon®monofocal lens (CNAOT0; Alcon; Texas, USA) were selected. Uncorrected Distance Visual Acuity (UDVA), Contrast Sensitivity (CS), kinetic perimetry, and refraction were measured 1 month following the second surgery and subjective vision was measured 6 months following the second surgery using a quality-of-life questionnaire.

Results:

There was no difference in postoperative UDVA (P=0.94), CS (P>0.05), or refraction (P=0.64) between eyes that received the Clareon® and AcrySof® IQ lenses. Clareon® eyes had a higher incidence of glare/haloes and positive dysphotopsia while AcrySof® IQ eyes had a higher incidence of negative dysphotopsia. Patient satisfaction was similar between the groups (P=0.86), although 25% of patients reported more clarity in the eye that received the Clareon® lens. The incidence of posterior capsular opacification was low for both groups.

Conclusion:

Clareon® and AcrySof® IQ lenses perform similarly, providing good refractive, visual, and subjective outcomes. Clareon® is available as a preloaded lens option and may reduce PCO and the need for Nd: YAG capsulotomy.

Distinct differences in anterior chamber configuration and peripheral aberrations in negative dysphotopsia

Clinical evaluations combined with ray-tracing analyses in patients with negative dysphotopsia supported the role of an increased angle κ.

Purpose:

To provide insights into the anatomical characteristics associated with negative dysphotopsia using quantitative clinical data.

Setting:

Department of Ophthalmology, Leiden University Medical Center, Leiden, the Netherlands.

Design:

Case-control study.

Methods:

Anterior chamber tomography and peripheral aberrometry were measured in 27 pseudophakic patients with negative dysphotopsia and 30 pseudophakic control subjects. Based on these measurements, the total corneal power, anterior chamber depth, pupil location and diameter, iris tilt, and peripheral ocular wavefront up to 30 degrees eccentricity were compared between both groups. In addition, ray-tracing simulations using pseudophakic eye models were performed to establish a connection between these clinical measurements and current hypotheses on the etiology of negative dysphotopsia.

Results:

Twenty-seven patients with negative dysphotopsia and 25 pseudophakic controls were included in the analysis. The patients with negative dysphotopsia had a smaller (P = .03/P = <.01) and more decentered (P < .01) pupil than that of the pseudophakic controls. In addition, an increased temporal-tilted iris (P < .01) and an asymmetric peripheral aberration profile were observed in patients with negative dysphotopsia, of which the latter was also apparent in several ray-tracing models. The combination of these in vivo results and ray-tracing simulations indicated that patients with negative dysphotopsia had a temporal-rotated eye, which confirmed the hypothesized relation between negative dysphotopsia and an increased angle κ.

Conclusions:

Patients with negative dysphotopsia had a smaller pupil and an increased angle κ, which made them more susceptible to experiencing a shadow in the temporal visual field.

Dysphotopsiae and functional quality of vision after implantation of an intraocular lens with a 7.0 mm optic and plate haptic design

PURPOSE

To determine the impact of IOL with 7.0 mm optic and plate haptic design on incidence of dysphotopsiae and visual functions after cataract surgery.

SETTING

Day-care clinic.

DESIGN

A prospective monocentric randomized patient-blinded comparative clinical study.

METHODS

Following preoperative measurements, patients underwent cataract surgery with implantation of two IOL designs - with 7.0 mm optic and plate haptics (group 1) or with 6.0 mm optic and C-loop haptics (group 2). In month 1, 3 and 12 follow-ups patients were examined, answered a questionnaire regarding satisfaction, spectacle dependence, frequency and extent of positive and negative dysphotopsiae, and underwent contrast sensitivity, mesopic vision and glare sensitivity testing. The data were analyzed as nominal, ordinal and metric with Chi-Square, Mann-Whitney-U, Wilcoxon and t-tests.

RESULTS

Group 1 comprised 57 eyes (43 patients) and group 2 comprised 63 eyes (43 patients). Corrected distance visual acuity was the same between groups throughout the study. Group 1 showed significantly lower incidence of positive and negative dysphotopsiae in month 1 follow-up (p=0.021 and 0.015, respectively) and a higher satisfaction rate in month 3 follow-up (p=0.006). Mean contrast sensitivity and mesopic vision with and without glare were the same in both groups. Positive dysphotopsiae cases in month 12 follow-up revealed lower photopic contrast sensitivity (p=0.005, 0.036 and 0.047, respectively), longer AL and greater preoperative pupil dynamics (p=0.04 and 0.06).

CONCLUSIONS

The IOL design with 7.0 mm optic diameter and plate haptics reduces dysphotopsiae, provides good visual acuity, contrast sensitivity, mesopic vision with and without glare and high patient satisfaction.

Comparison of Visual Performance and Patient Satisfaction Outcomes with Two Trifocal IOLs with Similar Optical Design but Different Materials

Purpose

To compare clinical outcomes in a prospective trial of cataract surgery patients bilaterally implanted with two different trifocal intraocular lenses (IOLs) with very similar optical designs but consisting of different IOL materials (hydrophobic and hydrophilic).

Patients and Methods

Fifty-one patients (102 eyes) were randomized to receive trifocal IOLs bilaterally – FineVision POD F (hydrophilic) or FineVision POD F GF (hydrophobic) (both PhysIOL, Liége, Belgium). The follow-up period was 3 months. Outcome measurements included uncorrected distance (UDVA), corrected distance (CDVA), distance-corrected intermediate (DCIVA), and distance-corrected near visual acuity (DCNVA), refraction, negative dysphotopsia, optical quality of vision, contrast sensitivity under photopic and mesopic conditions, halometry (discrimination index), and patient-reported outcomes.

Results

At the final study visit, mean (SD) values for binocular UDVA, CDVA, DCIVA (80 cm), and DCNVA (40 cm) were −0.01 (0.06), −0.04 (0.04), 0.09 (0.10), and 0.10 (0.09) logMAR, respectively, for POD F, and 0.01 (0.08), −0.03 (0.03), 0.08 (0.1), and 0.13 (0.11) respectively, for POD F GF. Defocus assessments showed a continuous curve with a functional range of visual acuity (≤0.15 logMAR) from ~30 cm to infinity in both groups. The discrimination index was >0.85 for all patients, and both groups showed similar contrast sensitivity under photopic and mesopic conditions. At 3 months, no patient reported negative dysphotopsia, and high satisfaction rates were observed.

Conclusion

Clinical outcomes showed no significant difference between each lens when measured at 1 month and 3 months after implantation. This equally good clinical performance of hydrophilic and hydrophobic trifocal lenses allows the surgeon to choose the IOL material based on personal preferences or patients’ needs.

Pseudophakic negative dysphotopsia and intraocular lens orientation: a prospective double-masked randomized controlled trial

PURPOSE

To determine whether horizontal orientation of the intraocular lens optic-haptic junctions has an effect on the incidence of pseudophakic negative dysphotopsia.

METHODS

Single-centre prospective double-masked randomized controlled trial. 220 eyes of 201 participants undergoing routine cataract surgery were randomized to receive their intraocular lens either orientated with the optic-haptic junctions at 180° ('horizontal') or without manipulation following implantation (control). Patients were excluded according to age (<19 and > 99 years), coexisting eye disease affecting visual function and insufficient cognitive function to complete the study. In the fourth postoperative week, a telephone interview was conducted to determine rates of negative dysphotopsia. The data were analysed to provide the relative risk of negative dysphotopsia with horizontal orientation of the intraocular lens (IOL) optic-haptic junctions compared with standard treatment.

RESULTS

Orientating the IOL optic-haptic junctions horizontally halved the incidence of pseudophakic negative dysphotopsia in the fourth postoperative week (9/110 in the intervention group; 18/110 in the control group; RR: 0.50, 95% confidence interval: 0.235-1.064, p = 0.072). The overall incidence of negative dysphotopsia was 12.2% (27/220 participating eyes). No intraoperative adverse effects of intraocular lens rotation were reported.

CONCLUSION

The simple intraoperative manoeuvre of rotating the intraocular lens to orientate the optic-haptic junctions at 180° may be a safe and effective measure to reduce the risk of developing postoperative pseudophakic negative dysphotopsia in the first postoperative month. This is the first report that demonstrates the benefit of horizontal optic-haptic junction positioning to be sustained beyond the first postoperative day.

Pseudophakic Dysphotopsia: Review of Incidence, Cause, and Treatment of Positive and Negative Dysphotopsia

We reviewed the literature concerning positive dysphotopsia (PD) and negative dysphotopsia (ND) regarding cause, incidence, and clinical and surgical management. In addition, we summarized our surgical experience in managing dysphotopsia. A PubMed review, limited to English language articles, yielded 149 citations; multifocal (diffractive optic) and phakic intraocular lens (IOL) dysphotopsia were excluded. Overall, 39 articles were determined to be relevant for the objectives of this investigation. Regarding PD, 7 articles corroborated that the cause of PD is related primarily to internal reflection of oblique light rays that strike the square (truncated) edge of the IOL and are reflected onto the retinal surface. No round-edged foldable IOLs are available in the United States at this time, although IOLs modified with a round anterior edge and square posterior edge show a trend toward decreased incidence of PD. High index of refraction (I/R), surface reflectivity, and IOL optic design are additional causative factors for PD. Regarding the authors' surgical experience, changing the optic material to have a lower I/R improved PD symptoms in the large majority of patients. The cause of ND seems to be multifactorial and less well understood, with some disparity between clinical and laboratory findings. Four articles that explore using ray-tracing optical modeling suggest an "illumination gap," in which some temporally incident light rays to the nasal retina pass anterior to the IOL and some are refracted posteriorly by the IOL, resulting in a gap and resultant temporal shadow. However clinically, ND is associated invariably with well-centered in-the-bag IOLs. Other implicating factors include nasal anterior capsule override, haptic orientation, large-angle κ value, and high hyperopia. Persistent ND has been treated successfully or reduced with reverse (anterior) optic capture, sulcus IOL placement, piggyback IOLs, and neodymium:yttrium-aluminum-garnet nasal capsulectomy. Two articles reference a new optic edge designed to capture the anterior capsulotomy, mimicking reverse optic capture. Persistent dysphotopsia after cataract surgery is a significant cause for patient dissatisfaction. The cause and management of both ND and PD are of significance, and new IOL designs and alternative surgical strategies may help to mitigate these unintended side effects of IOL implantation.

Techniques of anterior capsulotomy in cataract surgery

Optimal outcomes of a cataract surgery largely depend on the successful performance of an anterior capsulotomy. It is one of the most important steps of modern cataract surgery which reduces the risk of capsular tears and ensures postoperative stable intraocular lens (IOL). Anterior capsulotomy is considered ideal if it is round, continuous, well-centered, and overlaps the implanted IOL around its circumference. If any of these features is missing, it can be a cause of impedance for desired surgical and visual outcomes. Manual can opener and manual capsulorhexis are the routine standard techniques employed for manual extracapsular cataract extraction and phacoemulsification, respectively. Recent increasing use of femtosecond laser cataract surgery has allowed cataract surgeons to obviate inherent inaccuracies of manual anterior capsulotomy techniques. There is an ongoing quest to find an ideal, risk free, and surgeon-friendly technique of anterior capsulotomy that can be employed for surgery in all types of cataracts.

Effect of active evaluation on the detection of negative dysphotopsia after sequential cataract surgery: discrepancy between incidences of unsolicited and solicited complaints

PURPOSE

To evaluate the incidence of negative dysphotopsia after sequential cataract surgery.

METHODS

Retrospective cohort study. The incidence of negative dysphotopsia was assessed by retrospective reviewing of medical records and interviews with patients between 2 and 4 months after sequential cataract surgery. Inclusion criteria were uncomplicated surgery, postoperative corrected distance visual acuity (CDVA) ≥20/25 Snellen and the absence of ocular comorbidity. The majority of intra-ocular lens (IOL) implants were one-piece AcrySof SN60WF (161 eyes). Other IOLs (29 eyes) were toric (SN6AT3-6), spherical (SN60AT), three-piece (MN60MA) and multifocal (ReSTOR SN6AD1, PanOptix TFNT00 and Finevision Micro F trifocal).

RESULTS

The study population was comprised of 95 patients with a mean age of 72 ± 10 years. Unsolicited complaints of negative dysphotopsia were reported by eight patients (8%), and two of them had a resolution of symptoms within 1 month of follow-up. Eighteen patients (19%) reported negative dysphotopsia at the time of the interview. Two patients reported bothersome negative dysphotopsia, and one of them was successfully treated with implantation of a supplementary IOL in the ciliary sulcus. Patients with negative dysphotopsia were younger than patients without dysphotopsia (p = 0.045) and had shorter axial eye length (p = 0.04), a tendency for higher IOL power (p = 0.09) and a higher CDVA (p = 0.001).

CONCLUSION

The incidence of unsolicited negative dysphotopsia after sequential cataract surgery appears to be a substantial underestimation of complaints identified in active interviewing. Although symptoms are not bothersome in the majority of cases, some patients with undiagnosed severe negative dysphotopsia may benefit from reassurance or secondary treatment.

Mini-review: Far peripheral vision

The region of far peripheral vision, beyond 60 degrees of visual angle, is important to the evaluation of peripheral dark shadows (negative dysphotopsia) seen by some intraocular lens (IOL) patients. Theoretical calculations show that the limited diameter of an IOL affects ray paths at large angles, leading to a dimming of the main image for small pupils, and to peripheral illumination by light bypassing the IOL for larger pupils. These effects are rarely bothersome, and cataract surgery is highly successful, but there is a need to improve the characterization of far peripheral vision, for both pseudophakic and phakic eyes. Perimetry is the main quantitative test, but the purpose is to evaluate pathologies rather than characterize vision (and object and image regions are no longer uniquely related in the pseudophakic eye). The maximum visual angle is approximately 105⁰, but there is limited information about variations with age, race, or refractive error (in case there is an unexpected link with the development of myopia), or about how clear cornea, iris location, and the limiting retina are related. Also, the detection of peripheral motion is widely recognized to be important, yet rarely evaluated. Overall, people rarely complain specifically about this visual region, but with "normal" vision including an IOL for >5% of people, and increasing interest in virtual reality and augmented reality, there are new reasons to characterize peripheral vision more completely.

The Complexities of Negative Dysphotopsia

The appearance of a dark shadow in the temporal periphery, otherwise known as negative dysphotopsia, continues to be a problem for some patients after routine uncomplicated cataract surgery. Etiologies include type and design of intraocular lens (IOL), anatomical features and dimensions of the eye, pupil size, angle kappa, relationship of the optic to the anterior capsule, and the position of the optic/haptic junction of the IOL. Although the primary etiology remains controversial, it is clear that the cause is multifactorial. All of the factors should be considered when attempting to prevent or treat this phenomenon.