Phakic Eyes Research Articles

Prevalence of myopic maculopathy in the German population: results from the Gutenberg health study

AimsTo determine the prevalence of myopic maculopathy in the general population in Germany and to analyse potential associations with ocular and systemic factors.DesignThe Gutenberg Health Study is a population-based study,...

Factors predicting normal visual acuity following anatomically successful macular hole surgery.

To assess the incidence of normal vision following anatomically successful macular hole surgery and associated clinical variables. Multicentre, retrospective chart review. Preoperative, intraoperative and postoperative clinical data were extracted from electronic medical records from seven European vitreoretinal units. Inclusion criteria were as follows: eyes undergoing primary vitrectomy for idiopathic full-thickness macular hole from January 2015 to January 2018; postoperative macular hole closure confirmed by spectral domain optical coherence tomography (OCT); preoperative pseudophakia or phakic eyes receiving combined cataract surgery; one-year follow-up. The primary outcome was 'normal vision' defined as a final best-corrected visual acuity (BCVA) ≥ 20/25. Univariate, multivariate and decision-tree analyses were conducted to evaluate the clinical variables associated with 'normal vision'. Odds ratios (OR) and confidence intervals (CIs) were calculated. Of 327 eligible cases, 91 (27.8%) achieved 'normal vision' at 1year. Multivariate analysis identified variables significantly associated with 'normal vision': shorter symptom duration (odds ratio [OR]=1.05; 95% confidence interval [CI]:1.02-1.09; p=0.002), smaller preoperative OCT minimum linear diameter (OR per 100-micron increase=1.65; 95%CI:1.31-2.08; p<0.001) and better mean preoperative BCVA (OR=15.13; 95%CI: 3.59-63.65; p<0.001). The decision-tree analysis found that the most significant variable associated with 'normal vision' was symptom duration. 'Normal vision' was achieved in 70.6% of eyes operated within one week from symptom onset and in 45% of eyes with symptom duration between 1 and 3weeks. These findings suggested urgent surgery is justified for small macular holes of short duration.

Grating Visual Acuity in phakic, aphakic, and pseudophakic Poodles.

To compare the grating visual acuity (VA) measured by visual evoked potentials (VEP) in phakic, aphakic, and pseudophakic Poodles. Thirty-six Poodle dogs aged from 4 to 14years. Animals were allocated into three different groups according to their lens status: phakic group (n=12), aphakic group (n=12), and pseudophakic group (n=12). Grating VA was measured in cycles/degree (cpd) in all animals using the electrodiagnosis system Roland RETIport® in a dark room without using any mydriatic, sedative, or anesthetic drugs. The mean grating VA in the phakic, aphakic, and pseudophakic groups was 5.9±1.0cpd (20/102-Snellen equivalent), 2.6±0.7cpd (20/231), and 5.2±1.1cpd (20/116), respectively. The VA from aphakic eyes was significantly lower when compared to the phakic and pseudophakic eyes (P<.05). There was no significant difference in VA between phakic and pseudophakic eyes. The VEP is a useful tool for the evaluation of grating visual acuity in canines. The study showed that IOL implantation following phacoemulsification results in improved VA as measured by VEP compared to that of the aphakic eye and resulted in VA that was similar to that of the normal eye.

Peripapillary Retinal Nerve Fiber Layer Profile in Relation to Refractive Error and Axial Length: Results From the Gutenberg Health Study.

PurposeTo investigate the retinal nerve fiber layer profile measured by optical coherence tomography and its relation to refractive error and axial length.MethodsThe Gutenberg Health Study is a population-based study in Mainz, Germany. At the five-year follow-up examination, participants underwent optical coherence tomography, objective refraction and biometry. Peripapillary retinal nerve fiber layer (pRNFL) was segmented using proprietary software. The pRNFL profiles were compared between different refraction groups and the angle between the maxima, i.e., the peaks of pRNFL thickness in the upper and lower hemisphere (angle between the maxima of pRNFL thickness [AMR]) was computed. Multivariable linear regression analysis was carried out to determine associations of pRNFL profile (AMR) including age, sex, optic disc size, and axial length in model 1 and spherical equivalent in model 2.ResultsA total of 5387 participants were included. AMR was 145.3° ± 23.4° in right eyes and 151.8° ± 26.7° in left eyes and the pRNFL profile was significant different in the upper hemisphere. The AMR decreased with increasing axial length by −5.86°/mm (95% confidence interval [CI]: [−6.44; −5.29], P < 0.001), female sex (−7.61°; 95% CI: [−8.71; −6.51], P < 0.001) and increased with higher age (0.08°/year; 95% CI: [0.03; 0.14], P = 0.002) and larger optic disc size (2.29°/mm2; 95% CI: [1.18; 3.41], P < 0.001). In phakic eyes, AMR increased with hyperopic refractive error by 2.60°/diopters (dpt) (95% CI: [2.33; 2.88], P < 0.001).ConclusionsThe pRNFL profiles are related to individual ocular and systemic parameters.Translational RelevanceBiometric parameters should be considered when pRNFL profiles are interpreted in diagnostics, i.e., in glaucoma.

Efficacy and safety of intravitreal dexamethasone implant in treatment naïve eyes with diabetic macular edema: Real world experience.

To evaluate the efficacy and safety of intravitreal dexamethasone implant in treatment naïve eyes with diabetic macular edema (DME). A retrospective analysis of treatment naïve eyes with DME which received intravitreal dexamethasone implant between January 2016 and March 2018 was done. Demographic details of the patients, ocular examination findings at baseline and on follow up visits were noted. Morphological features of DME and central macular thickness were noted on optical coherence tomography at each visit. The details regarding additional treatment for macular edema on follow up were noted. Sixty five eyes were included in the study. The mean age was 59.14 ± 9.59 years. The follow up ranged from 6 to 48 months. Psuedophakic eyes showed visual improvement whereas the phakic eyes showed stable vision. The central foveal thickness showed significant reduction (p = 0.05) in all the eyes. The best corrected visual acuity at final follow up (+0.65 logMAR) was slightly less as compared to baseline (+0.62 logMAR). Retreatment was needed in 37% eyes and antiglaucoma medications in 8% eyes. Cataract progression was noted in 24 eyes (37%); 17 eyes (26.1%) underwent surgery. Notably, 27 eyes (41.5%) had some degree of macular ischemia at baseline. And five eyes (7.7%) showed progression of retinopathy leading to vitreous hemorrhage. Dexamethasone implant is helpful in reducing the macular thickness and stabilizing the vision in treatment naïve DME; requiring less number of treatment sessions. However, it does not prevent progression of diabetic retinopathy. The visual improvement may be affected by cataract and macular ischemia.

Reading Speed as an Objective Measure of Improvement Following Vitrectomy for Symptomatic Vitreous Opacities.

There is currently no objective measure of the visual deficits experienced by patients with symptomatic vitreous opacities (SVOs) that would also correlate with the functional improvement they report following vitrectomy. This study aims to determine whether reading speed can be used as a reliable outcome measure to assess objectively the impact of both SVOs and vitrectomy on patients' visual performance. Twenty adult patients seeking surgery for SVO were included. Measures of visual function were obtained before and after vitrectomy using the Early Treatment Diabetic Retinopathy Study acuity chart, the National Eye Institute Visual Function Questionnaire, and the MNREAD acuity chart. In patients with nonopacified lenses (n = 10), maximum reading speed increased significantly from 138 to 159 words per minute after complete removal of SVOs by vitrectomy (95% confidence interval, 14-29; P < .001). Reading speed is impaired with SVOs and improves following vitrectomy in phakic and pseudophakic eyes with clear lenses. Reading speed is a valid objective measure to assess the positive effect of vitrectomy for SVOs on near-distance daily life activities. [Ophthalmic Surg Lasers Imaging Retina. 2020;51:456-466.].

Ocular Manifestations and Biometrics in Marfan's Syndrome from Eastern Nepal.

PurposeTo evaluate the ocular characteristics of Marfan’s syndrome (MFS) fulfilling the revised Ghent-2 nosology in Eastern Nepal.Materials and MethodsA hospital-based observational and cross-sectional study was conducted. Ocular manifestations and biometrics were incorporated. Patients were subdivided into adults (16 years or older) and children (5–15 years). Ocular biometric parameters consisted of values of refractive error, keratometry readings, anterior chamber depth (ACD), central corneal thickness (CCT), lens thickness (LT) and axial length (AL).ResultsA total of 34 eyes of 17 patients with MFS were included, where 32 eyes were phakic. Mean age of the study participants was 14.5 ± 9.1 years. The mean best corrected visual acuity (BCVA) of phakic eyes was 0.99 ± 0.82 LogMAR. Myopia greater than −3 diopters (D) was present in 28/34 (82.35%) eyes. The average spherical equivalent was −12.34 ± 8.85 D. Ectopia lentis (EL) was present in 24/32 (75%) eyes where superonasal was the most common subluxation in 10/24 (41.7%) eyes. AL was longer in adults 26.54 ± 4.42 mm compared to 25.21 ± 1.93 mm in children. Likewise, LT in adults was 4.9 ± 0.70 mm and 4.40 ± 0.59 mm in pediatric participants. Flat corneas were noted in both the groups with an average of 41.53 ± 2.21 D. The mean CCT and ACD were 524.62 ± 21.74 μm and 3.64 ± 0.80 mm, respectively. There was a negative association between the AL and the average corneal curvature (Kmed, correlation coefficient −0.11, p=0.54).ConclusionMyopia is the foremost ocular involvement with significant visual disability in MFS. Though, AL and corneal curvature are not included in the revised Ghent-2 nosology, we strongly recommend these parameters to be considered during ophthalmic evaluation in suspected and diagnosed cases of MFS in the absence of genetic testing.

Intraocular pressure might play a role in the surgical management of patients with epiretinal membrane.

To investigate the prognostic factors and visual outcomes for patients with epiretinal membrane after pars plana vitrectomy and possible interactions between multiple factors. A retrospective chart review of adult patients with epiretinal membrane treated with pars plana vitrectomy performed by a single surgeon between February 1, 2015, and January 31, 2017 was conducted. The surgical procedures included standard 25-gauge vitrectomy with peeling of the epiretinal membrane and internal limiting membrane (ILM). Factors including age, sex, vision, intraocular pressure (IOP), lens status, and baseline optical coherence tomography angiography were analyzed to determine any association with visual outcomes. IOP and lens status were evaluated at every visit point and were used for analysis. Visual changes after pars plana vitrectomy in patients with epiretinal membrane were significantly associated with time, lens status, baseline ellipsoid zone integrity, baseline vision, baseline parafoveal vessel density of superficial capillary plexus (SPVD), and IOP. Further investigation using Johnson-Neyman analysis revealed that vision improved over time, especially in pseudophakic eyes. High IOP at baseline or during follow-up was identified as a significant factor associated with limited visual improvement. Our study showed that vision improved over time after vitrectomy for patients with epiretinal membrane. The surgical outcomes are more stable in pseudophakic eyes, and vision improved after cataract extraction in phakic eyes. IOP should be managed and monitored closely to optimize surgical and visual outcomes in patients.

Imaging of Age-Related Macular Degeneration by Adaptive Optics Scanning Laser Ophthalmoscopy in Eyes With Aged Lenses or Intraocular Lenses.

PurposeTo assess the performance of adaptive optics scanning laser ophthalmoscopy (AOSLO) in a large sample of eyes with or without age-related macular degeneration (AMD) and with cataracts or intraocular lenses (IOLs).MethodsPatients with various degrees of AMD and age-similar normal subjects underwent fundus photography. Cataract severity and IOL clarity were assessed by fundus reflex photographs. In phakic eyes, lenticular opacity was graded as nuclear, cortical, or posterior subcapsular cataract. In eyes with IOLs, lens clarity was assessed by posterior capsule opacification (PCO). Quality of AOSLO images of the macular photoreceptor mosaic was classified as good, adequate or inadequate by human graders in a subjective assessment of cone visibility.ResultsA total of 159 eyes in 80 subjects (41 males, 39 females, aged 72.5 ± 11.5 years, 16 normals) were examined. Seventy-nine eyes had IOLs, and 80 eyes were phakic. AOSLO produced good images in 91 eyes (57%), adequate images in eight eyes (5%), and inadequate images in 27 eyes (17%). AOSLO did not acquire images in 33 eyes (21%), because of dense lenticular opacity, widespread PCO, or problems specific to individual subjects.ConclusionsAOSLO images considered at least Adequate or better for visualizing cone photoreceptors were acquired from 62% of study eyes.Translational RelevanceAOSLO can be used as an additional imaging modality to investigate the structure of cone photoreceptors in research on visual function in AMD and in clinical trials involving older patients.

“Basket” mattress suture to manage positive vitreous pressure during penetrating keratoplasty

ObjectiveTo describe a new/modified technique to manage posterior vitreous pressure (PVP) during penetrating keratoplasty (PKP) and report a small series. DesignRetrospective interventional case series and technique description. ParticipantsPKP eyes necessitating mattress suture placement owing to PVP. MethodsRetrospective chart review from 2016 to 2019 was undertaken. Placed prophylactically (before trephination) or after trephination, the mattress suture is placed limbus-to-limbus across the anterior chamber. A second mattress suture can be placed in the opposite meridian (perpendicularly) for added support (safety basket configuration). Variations of suture technique are described based on lens status (i.e., phakic, pseudophakic, aphakic) and intraoperative timing. Parameters assessed included demographics, lens status, suture indications, intraoperative technique details, successful PKP completion, and presence of primary failure. ResultsThere were 6 phakic eyes (5 patients) and 9 pseudophakic/aphakic eyes (8 patients). Indications for the phakic subgroup were obesity (83%), poor scleral rigidity (83%), repeated iris prolapse (67%), dense mature cataract (33%), and planned large-diameter PKP (33%). Indications for pseudophakic/aphakic eyes included intraocular lens/iris prolapse (100%), pre-existing iris defects (67%), and planned large-diameter PKP (33%). Successful PKP was performed in all cases. Whereas one case had residual corneal edema in the setting of a persistent epithelial defect owing to limbal stem cell deficiency, all other cases demonstrated no primary graft failure. ConclusionsAlthough increased PVP can present a stressful and challenging situation, it is important to have multiple options for management. This simple mattress suture technique normalizes the lens-iris complex behaviour and appears safe for the donor graft.

Medium-term tamponade with vitrectomy and perfluorodecalin for the management of complex retinal detachments.

To describe the clinical presentation, anatomical and visual outcome of a series of patients in our department with complex retinal detachments, managed with vitrectomy and perfluorodecalin (PFD) for medium-term tamponade. Retrospective case series. Retrospective analysis of the medical records of all patients in the last 6 years presenting with complex retinal detachment managed with vitrectomy where PFD was used as a medium-term tamponade. A total of 85 eyes in 85 patients were included in the study, with a mean follow-up period of 16.0 ± 2.67 months (range 3-59). About 26 detachments presented with associated PVR-C, and 10 had giant retinal tears. The location of the retinal detachment was inferior in 40% of cases, and total in 18.9% of cases. Anatomical success, defined as retinal reattachment at 12 months, was achieved in 98.8% of cases, and there was a mean improvement in BCVA of logMAR 0.64 ± 0.20, which was statistically significant (p < 0.001, paired t-test 6.23). Of the 41 phakic eyes included in the study, 20 underwent cataract surgery within the follow-up period. In this case series, we have demonstrated a 98.8% anatomical success and significant improvement in BCVA, with no reports of retinal toxicity. Medium-term tamponade PFD appears to be an efficacious and safe technique for management of a variety of complex retinal detachments, including those secondary to GRT, the presence of PVR-C, inferior location, tractional, traumatic, and re-detachments.

Long-term follow-up of diabetic macular edema treated with dexamethasone implant: a real-life study.

To evaluate the efficacy and safety of intravitreal dexamethasone implant (DEX-implant) for diabetic macular edema (DME) in real-life practice with an extended follow-up for up to 5 year. This multicentric retrospective study reviewed 227 eyes of 152 patients with DME treated by DEX-implant. Main outcome measures included changes in best corrected visual acuity (BCVA), central macular thickness (CMT), time to retreatment and incidence of adverse effects. The mean number of DEX-implant received by patients was 2.6 (± 2.2) with a mean (SD) follow-up of 20.1 (± 15.8) months, median [IQR] 15.8 [7.4-30.1]. The mean time of retreatment was 6.9months. The mean maximal BCVA gain during follow-up was 12.3 (± 12.7) letters. A gain of ≥ 5, ≥ 10 and ≥ 15 letters from baseline BCVA was obtained for 71.8%, 48.9% and 34.8% of eyes, respectively. A total of 62.6% of eyes presented a significant anatomical response (decrease of CMT ≥ 20%), and DME was resolved (absence of cystoid macular spaces on OCT) in 37% of cases at the end of the follow-up. A transient increase in intraocular pressure ≥ 25mmHg occurred in 14.1% of eyes, and cataract surgery was performed for 49.1% of the phakic eyes during the follow-up. Four eyes developed a proliferative diabetic retinopathy. This large cohort study showed favorable long-term outcomes when using DEX-implant, which provides substantial long-term benefits in the treatment of DME in real life.

Minimally Invasive Technique for Choroidal Fluid Drainage.

BackgroundThis study describes a simple technique for the treatment of kissing choroidal detachment. In contrast to the commonly used technique, this technique is minimally invasive, fast, sutureless, and does not require access to the vitreous space.MethodsA maintainer is inserted into the anterior chamber. A 25G trocar is inserted at the pars plana into the suprachoroidal space. Drainage is evident by the clear yellowish fluid freely emerging through the trocar, accompanied with deepening of the anterior chamber and an increase in the red reflex.ResultsFollow-up ultrasound 1 week after the surgery demonstrated resolution of the choroidal detachment. Net surgery time is about 10 minutes. No complications were noted.DiscussionThis is the first report of the technique performed in phakic eye, with video description of the steps and real-time clues for successful drainage even with reduced posterior segment visibility due to lens opacities.

Profiles of intraocular higher-order aberrations in healthy phakic eyes: prospective cross-sectional study.

Ocular wavefront aberration is a crucial optical factor affecting retinal imaging. Internal aberrations contributed to compensation mechanism of ocular aberration. However, previous studies mainly focused on total and corneal higher order aberrations, and little is known about the profile of internal HOA (IHOA) in healthy subjects. Participants with healthy crystalline lenses were prospective enrolled. The root mean square (RMS) of IHOAs for a pupil diameter of 4 mm were measured with an iTrace aberrometer. Lenticular parameters were measured with a swept source anterior segment optical coherence tomography (AS-OCT). Regression analyses were used to determine factors associated with logarithmic IHOAs. Sixty-six Chinese participants (132 eyes) ranging from 5 to 59 years were analyzed. Logarithmic IHOA was positively associated with axial length (AL) (coefficient =0.101, P=0.016), and negatively associated with ocular refraction (coefficient =-0.032, P=0.023). Logarithmic internal coma increased by 0.161/mm (P=0.016) as AL became longer and decreased by 0.081/diopter (P<0.001) as ocular refraction became hyperopic. Lens tilt (coefficient =-0.121, P=0.037), decentration (coefficient= 3.027, P=0.003), and radius of anterior lens surface curvature (RAL) (coefficient= 0.096, P=0.026) were associated with logarithmic internal trefoil. lens tilt was also associated with logarithmic internal spherical aberration (coefficient =-0.195, P=0.018) and second astigmatism (coefficient =-0.132, P=0.030). Binocularly, the extent of coma, trefoil was different, while that of spherical aberration, secondary astigmatism was consistent. The vectors of the same type of IHOAs were nearly paralleled. IHOAs are mainly affected by ocular refraction, RAL, lens tilt and decentration. Intraocular differences and directions of higher-order aberrations follow certain rules, and their effects on visual function warrant further study.

Tube in Sulcus in a Post-Therapeutic Penetrating Keratoplasty Phakic Eye

Tube in Sulcus in a Post-Therapeutic Penetrating Keratoplasty Phakic Eye

Histopathological changes in the anterior segment with anterior and posterior chamber intraocular lens

ObjectivePatients have shown a lowering of intraocular pressure (IOP) after cataract surgery. Histopathology studies have reported trabecular meshwork (TM) changes in pseudophakic eyes with posterior chamber intraocular lens (PCIOL) and have eluded to the mechanisms for IOP decrease. Unlike PCIOLs, TM histopathology changes after implantation of an anterior chamber intraocular lens (ACIOL) have not been studied, to our knowledge. Therefore, this study aims to examine the histopathological changes in both the TM and corneal endothelium among donor eyes with ACIOL, PCIOL, and phakic eyes. MethodsForty fixed postmortem donor eyes were obtained, sectioned, and embedded. Slides were stained with Masson's trichrome and CD31 vascular endothelial antibody, and further digitalized. Customized Medical Parachute TMAN software quantified the cellular components, the trabecular extracellular matrix (ECM), ECM fibrosis, and trabecular area. Schlemm's canal and corneal endothelium were quantified across the ACIOL, PCIOL, and phakic groups. ResultsCellular area component of the TM was lower in the ACIOLs and PCIOLs than in phakic eyes, but statistically significant only between PCIOL and phakic eyes (p = 0.0023). ECM area component, TM fibrosis score and TM lamellae area, ciliary process fibrosis, and CD31 expression in Schlemm's canal showed no differences (p = 0.40, 0.99, 0.10, 0.83, 0.45). Significantly lower corneal endothelial cells were seen in ACIOLs compared with both PCIOLs and phakic eyes (p = 0.0002). ConclusionsACIOLs and PCIOLs in our sample group showed that there is loss of cellular components in the TM compared with the phakic eyes, with PCIOLs displaying the least amount of TM cells statistically, in this cohort. The ACIOLs led to a greater loss of corneal endothelial cells than both PCIOLs and phakic eyes after cataract surgery. The endothelial cells in Schlemm's canal did not seem to be affected by the IOL placements. Therefore, this study illustrates that there are histopathological differences seen with the placements of ACIOLs in both TM and cornea.

European Vitreoretinal Society Macular Hole Study, Prognostic Factors for Anatomical and Functional Success

Background: To identify prognostic preoperative and intraoperative factors for anatomical and visual success of idiopathic macular hole (MH) surgery.&#x0D; Methods: We conducted a non-randomized, collaborative multicenter study using data of 4207 MH surgery from 140 surgeons. Main study outcomes were anatomical closure and best corrected visual acuity (BCVA) improvement postoperative at 6-12 months.&#x0D; Results: Information on anatomical success was available for 4138 eyes of 4207 operations. Anatomical closure of MH was achieved in 85.7% (3546 eyes). Closure was higher in smaller MH (stages 1-2 versus stage 3: OR=0.35; stage 2 versus stage 4: OR=0.16, and in MH with shorter duration before the operation (OR=0.94). Macular Holes were more likely to close when dyes were used to facilitate internal limiting membrane (ILM) peeling (odds ratio=1.73 to 3.58). The most important predictors of postoperative BCVA were the preoperative BCVA (estimate=0.39, p&lt;0.001) and closure of the macular hole (estimate=0.34, p&lt;0.001). We observed Larger improvement in BCVA in combined vitrectomy and phacoemulsification (estimate = 0.10) and post cataract surgery in phakic eyes (estimate=0.05). Retinal tears occurred in 5.1% of eyes, and were less with use of trocars (OR= -1.246) and in combined vitrectomy/ phacoemulsification surgery (OR= -0.688).&#x0D; Conclusion: This international survey confirmed that staining with dyes improves anatomical results but not visual outcomes. After surgery, visual acuity improved during the first year, and final visual acuity was better in both pseudophakic eyes and eyes that underwent cataract surgery during the first year following MH repair.

Discordant vascular parameter measurements in diabetic and non-diabetic eyes detected by different optical coherence tomography angiography devices.

PurposeTo compare quantitative changes in macular parameters in diabetic patients detected by two optical coherence tomography angiography (OCTA) instruments.Methods80 phakic eyes were classified as no diabetes, diabetes without diabetic retinopathy (DR), mild non-proliferative diabetic retinopathy (NPDR), and severe NPDR or proliferative DR (PDR). OCTA was performed using devices from two manufacturers (Zeiss and Heidelberg). Superficial and deeper vascular skeleton density (SVSD, DVSD), superficial and deeper vessel area density (SVAD, DVAD), choriocapillaris flow voids (CCFV), and choroidal flow voids (CFV) were calculated. Inter-device comparisons were performed using the size comparison index (SCI) and the discrepancy index (DI).ResultsThe two devices were inconsistent in SVSD, DVSD, DVAD, CCFV and CFV parameters (all P < 0.05). In addition, the SCI was positive for DVAD (all P < 0.001) and negative for SVSD, DVSD, CCFV and CFV in all groups (all P <0.001), except for DVSD in severe NPDR or PDR. The discrepancy index was not significantly different among groups for SVD, SPD, DVD, DPD and CFV (all P> 0.05). The mean DI of CCFV was statistically different between the four groups (P < 0.001).ConclusionsThe two instruments were largely inconsistent in the measurement of macular parameters relevant to DR. The choice of imaging device can impact OCTA analytics and should be taken into account when drawing conclusions about DR-related changes.

The Effect of Pharmacological Dilation on Calculation of Targeted and Ideal IOL Power Using Multivariable Formulas.

BackgroundTo examine the effect of pharmacologic dilation on biometric parameters measured by the Lenstar LS 900, and whether these changes affect the power of the calculated intraocular lens (IOL) using multivariable formulas in an undilated versus pharmacologically dilated state.MethodsProspective study of 98 phakic eyes from 53 patients. Axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), and keratometry (K) readings were measured. The first set of measurements was taken prior to dilation. After dilation (pupil diameter ≥ 6.0 mm), a second set of measurements was taken. The Barrett, Olsen, Hill-RBF, Haigis, SRK/T, and Holladay I formulas were used to calculate IOL power before and after dilation. Two calculation methods were used: method A used a commonly available IOL targeted to achieve the lowest myopic spheroequivalent residual refraction; method B calculated ideal IOL power for emmetropia.ResultsStatistically significant increases were seen in CCT (p < 0.01), ACD (p < 0.01), and AL (p < 0.01) whereas a statistically significant decrease was seen in LT (p < 0.01) post dilation. Using method A, the percentage of eyes which would have received an IOL with 0.5 D or 1.0 D of higher power, if post-dilation measurements were used, were 25.5%, 30.6%, 20.4%, and 23.5% for Barrett, Olsen, Hill-RBF, and Haigis, respectively. Using method B, only Haigis and Olsen had a statistically significant increase in ideal IOL power.ConclusionsPharmacologic dilation can be associated with an increase in non-custom IOL dioptric power when using multivariable formulas, which may lead to a myopic surprise.

Experimental Model of Far Temporal Field Negative Dysphotopsia Generated in Phakic Eyes.

PurposeThe axial separation between the iris and the intraocular lens (IOL) in pseudophakic eyes can cause rays originating from the far temporal field to miss the IOL, resulting in negative dysphotopsia (ND). We developed an experimental model to test the hypothesis that obstruction of rays from the far temporal field can generate ND and an accompanying loss of visual sensitivity in the far temporal field.MethodsThe right eyes of 10 phakic subjects were fitted with soft contact lenses containing a 5.50-mm central clear zone and a 12-mm outer diameter opaque annulus. In three of the subjects, eyes were dilated with 1% tropicamide solution, and effective aperture diameters were determined optically (pupil camera) and psychophysically (narrow beam detection). Visual field extent (Goldmann bowl) and temporal and inferotemporal meridian sensitivities (Octopus perimeter) were measured. A wide-angle model was constructed to quantify the impact of the annular opacity on retinal illuminance.ResultsAll 10 subjects observed a dark crescent in the far temporal and inferotemporal fields. The opaque annulus reduced effective horizontal pupil diameters from 8 mm to 5.5 mm on-axis and from >2 mm to <1 mm at 90°. Perimetry revealed a 10° reduction in temporal and inferotemporal field extent and increasing loss of sensitivity beyond 70°. The wide-angle model confirmed significant vignetting (>50% beyond 70°), approaching zero retinal illuminance beyond 85°.ConclusionsVignetting of rays originating from the far temporal field by axially separated apertures can create symptoms mirroring perceptual reports of negative dysphotopsia in symptomatic pseudophakic patients.