Nasal Visual Field Research Articles

Chromatic cues for the sign of defocus in the peripheral retina.

Detecting optical defocus at the retina is crucial for accurate accommodation and emmetropization. However, the optical characteristics of ocular defocus are not fully understood. To bridge this knowledge gap, we simulated polychromatic retinal image quality by considering both the monochromatic wavefront aberrations and chromatic aberrations of the eye, both in the fovea and the periphery (nasal visual field). Our study revealed two main findings: (1) chromatic and monochromatic aberrations interact to provide a signal to the retina (chromatic optical anisotropy) to discern positive from negative defocus and (2) that chromatic optical anisotropy exhibited notable differences among refractive error groups (myopes, emmetropes and hyperopes). These findings could enhance our understanding of the underlying mechanisms of defocus detection and their subsequent implications for myopia control therapies. Further research is needed to explore the retinal architecture's ability to utilize the optical signals identified in this study.

Investigating the impact of asymmetric macular sensitivity on visual acuity chart reading in choroideremia.

Degeneration in choroideremia, unlike typical centripetal photoreceptor degenerations, is centred temporal to the fovea. Once the fovea is affected, the nasal visual field (temporal retina) is relatively spared, and the preferred retinal locus shifts temporally. Therefore, when reading left to right, only the right eye reads into a scotoma. We investigate how this unique property affects the ability to read an eye chart. Standard- and low-luminance visual acuity (VA) for right and left eyes were measured with the Early Treatment of Diabetic Retinopathy Study (ETDRS) chart. Letters in each line were labelled by column position. The numbers of letter errors for each position across the whole chart were summed to produce total column error scores for each participant. Macular sensitivity was assessed using microperimetry. Central sensitivity asymmetry was determined by the temporal-versus-nasal central macular difference and subsequently correlated to a weighted ETDRS column error score. Healthy volunteers and participants with X-linked retinitis pigmentosa GTPase regulator associated retinitis pigmentosa (RPGR-RP) were used as controls. Thirty-nine choroideremia participants (median age 44.9 years [IQR 35.7-53.5]), 23 RPGR-RP participants (median age 30.8 years [IQR 26.5-40.5]) and 35 healthy controls (median age 23.8 years [IQR 20.3-29.0]) were examined. In choroideremia, standard VA in the right eye showed significantly greater ETDRS column errors on the temporal side compared with the nasal side (p = 0.002). This significantly correlated with greater asymmetry in temporal-versus-nasal central macular sensitivity (p = 0.04). No significant patterns in ETDRS column errors or central macular sensitivity were seen in the choroideremia left eyes, nor in RPGR-RP and control eyes. Difficulty in tracking across lines during ETDRS VA testing may cause excess errors independent of true VA. VA assessment with single-letter optotype systems may be more suitable, particularly for patients with choroideremia, and potentially other retinal diseases with asymmetric central macular sensitivity or large central scotomas including geographic atrophy.

Visual Field Improvement in Non-Arteritic Posterior Ischemic Optic Neuropathy in a Patient Treated with Intravenous Steroids

A 50-year-old man presented with a nasal visual field defect in the left eye. His medical history was unremarkable. On ophthalmic examination, his best-corrected visual acuity (BCVA) was 1.2 in both eyes. Fundoscopy revealed no abnormalities in either eye. Goldmann visual field test showed a nasal visual field defect in the left eye. The patient was diagnosed with NPION of the left eye and was followed up without treatment. However, four days after the initial visit, his BCVA decreased to counting finger in the left eye. Goldmann visual field test showed a complete nasal visual field defect with central absolute scotoma. Following admission, the patient was treated for 3 days with intravenous methylprednisolone pulse therapy. Three months later, his BCVA was improved to 0.8 in the left eye, but central relative scotoma was remained. Six months later, his BCVA was maintained at 0.8, and central relative scotoma was disappeared. However, the optic disc looked diffusely pale in the left eye. This case highlights that steroid therapy is an option for severe cases with posterior ischemic optic neuropathy.

The role of extrinsic and intrinsic factors in perceptual filling-in of the blind-spot with variegated color and texture stimuli

Vision scientists dedicated their efforts to unraveling the mechanism of filling-in at the blind-spot (BS) through numerous psychophysical experiments. The prevalent interpretation, emphasizing active filling-in, has spurred extensive research endeavors. In a parallel vein, a pertinent study highlighted the predominance of the nasal Visual Field (VF) over the temporal one and postulated the role of the Cortical Magnification Factor (CMF) in explaining the asymmetry of filling-in. In this study, we first replicated this experiment and then conducted BS-specific psychophysical experiments employing various bi-colored and bi-textured (patterned) stimuli. We observed that nasal dominance is not persistent in the context of the spread of perception for BS filling-in. We posit that the visual information processing priority index (VIPPI), comprising the CMF (an intrinsic factor unaffected by stimulus characteristics) and relative luminance (an extrinsic factor dependent on stimulus characteristics), governs the spread of perception for filling-in in case of diverse neighborhoods of the BS.

Effects of intraocular scatter on near peripheral vision.

Both cataracts and age-related macular degeneration (AMD) may occur with aging and are often developed simultaneously. We performed a study to better characterize the impact of induced scatter on the quality of vision in the near periphery, a region where individuals with AMD typically maintain their functional vision. We used an optical instrument as a cataract simulator based on projecting at the eye's pupil plane phase masks with controlled spatial properties generated with a spatial light modulator. The phase wavefronts were designed to accurately replicate the angular distribution of light intensity in the retina found in cataractous eyes with different severities. The induced amount of scatter ranged from values of straylight (S) from 10 to 85 degree2/sr, which corresponds from normal aging eye to advanced cataract stages. Mesopic visual acuity (VA) and contrast sensitivity (CS) at 3 cycles per degree were measured at the fovea and two retinal eccentricities (5 and 10 degrees in nasal visual field). We observed a consistent linear decline in VA (expressed in LogMAR) as the amount of induced scatter (quantified by the straylight parameter S) increased, both at the fovea and in the periphery. The effect of induced scattering on mesopic VA and CS at the fovea and the near periphery was evaluated. We found a relatively lower impact of scatter in the near periphery. This may explain the modest improvement in vision often found after cataract surgery in patients with AMD.

Discrimination ability of central visual field testing using stimulus size I, II, and III and relationship between VF findings and macular ganglion cell thickness in chiasmal compression.

To compare the relationship between macular ganglion cell layer (mGCL) thickness and 10-2 visual field (VF) sensitivity using different stimulus sizes in patients with temporal hemianopia from chiasmal compression. A cross-sectional study was conducted involving 30 eyes from 25 patients with temporal VF loss on 24-2 SITA standard automated perimetry due to previous chiasmal compression and 30 healthy eyes (23 controls). Optical coherence tomography (OCT) of the macular area and 10-2 VF testing using Goldmann stimulus size I (GI), II (GII), and III (GIII) were performed in the Octopus 900 perimeter. For the sake of analysis, mGCL thickness and VF data were segregated into four quadrants (two temporal and two nasal) and two halves (temporal and nasal) centered on the fovea, in order to evaluate separately both the severely affected nasal hemi-retina corresponding to the temporal VF sectors and the subclinically affected temporal hemi-retina corresponding to the nasal VF sectors. Data from patients and controls were compared using generalized estimated equations. The discrimination ability of GI, GII, and GIII was evaluated, as was the correlation between mGCL and 10-2 VF sensitivity using GI, GII, and GIII. All mGCL parameters in the nasal and temporal halves of the retina were significantly reduced in patients compared to controls. 10-2 VF test sensitivity using GI, GII, and GIII was significantly lower in patients than in controls (p≤0.008) for all parameters, except the three nasal divisions when using GI (p = 0.41, 0.07 and 0.18) Significant correlations were found between temporal VF sectors (all stimulus sizes) and the corresponding nasal mGCL measurements, with similar discrimination ability. Significant correlations were also observed between all three nasal VF divisions and the corresponding temporal mGCL thickness when using stimulus sizes I and II, but not stimulus size III. On 10-2 VF testing, GII outperformed GI and GIII with regard to discrimination ability and structure-function correlation with mGCL thickness in the subclinically affected nasal part of the VF in patients with chiasmal compression. Our findings suggest that the use of GII can enhance the diagnostic power of 10-2 VF testing in early cases of chiasmal compression, although further studies are necessary to support this conclusion.

Visual Field Deficits in Albinism in Comparison to Idiopathic Infantile Nystagmus.

This is the first systematic comparison of visual field (VF) deficits in people with albinism (PwA) and idiopathic infantile nystagmus (PwIIN) using static perimetry. We also compare best-corrected visual acuity (BCVA) and optical coherence tomography measures of the fovea, parafovea, and circumpapillary retinal nerve fiber layer in PwA. VF testing was performed on 62 PwA and 36 PwIIN using a Humphrey Field Analyzer (SITA FAST 24-2). Mean detection thresholds for each eye were calculated, along with quadrants and central measures. Retinal layers were manually segmented in the macular region. Mean detection thresholds were significantly lower than normative values for PwA (-3.10 ± 1.67 dB, P << 0.0001) and PwIIN (-1.70 ± 1.54 dB, P<0.0001). Mean detection thresholds were significantly lower in PwA compared to PwIIN (P<0.0001) and significantly worse for left compared to right eyes in PwA (P=0.0002) but not in PwIIN (P=0.37). In PwA, the superior nasal VF was significantly worse than other quadrants (P<0.05). PwIIN appeared to show a mild relative arcuate scotoma. In PwA, central detection thresholds were correlated with foveal changes in the inner and outer retina. VF was strongly correlated to BCVA in both groups. Clear peripheral and central VF deficits exist in PwA and PwIIN, and static VF results need to be interpreted with caution clinically. Since PwA exhibit considerably lower detection thresholds compared to PwIIN, VF defects are unlikely to be due to nystagmus in PwA. In addition to horizontal VF asymmetry, PwA exhibit both vertical and interocular asymmetries, which needs further exploration.

Distal Nasal Part of the Visual Field and RNFL in Primary Open-Angle Glaucoma.

The aim of this study was to compare changes in the conventionally undiagnosed distal nasal visual field with RNFL in patients with early primary open-angle glaucoma (POAG). 59 eyes of 32 patients (18 women, 14 men) with early stage POAG were included. All eyes were found to have a normal visual field (fast threshold program of 50 degrees nasally and 22 degrees temporally) with the Medmont M700. Visual acuity was 1.0 (with a possible correction ±3 D), and they had no other ocular pathology except glaucoma. The visual field was subsequently examined with the same instrument by moving the fixation point 40 degrees temporally (spatially adaptive program) and simultaneously turning the head 10 degrees nasally. A total of 89 examination points were included using flicker stimuli in a range of 0-120 degrees nasally. Nerve fiber layer (RNFL) and vessel density (VD) was measured using the in-built software of the Avanti RTVue XR instrument. Using Pearson's correlation coefficient, the results of visual field examination with RNFL without and after correction (by subtracting VD from total RNFL value) in the superior-nasal (SN-5) and inferior-nasal (IN-8) segments were compared. In all eyes, changes were found in the distal periphery of the nasal part of the visual field. No correlation was noted by comparison with RNFL. After adjusting RNFL for VD, we observed no correlation in the SN segment (5) (r=-0.03) and a very weak correlation in the IN segment (8) (r=-0.16). With a normal visual field tested by the rapid threshold glaucoma program, changes in the distal part of the nasal periphery of the visual field were found in the entire cohort and did not correlate with the RNFL and RNFL results after correction from VD.

Correlation between Residual Sensitivity in the Central Inferior Nasal Visual Field and Visual Function in Chronic Leber Hereditary Optic Neuropathy Patients

Introduction: Leber hereditary optic neuropathy (LHON) is a maternally inherited, acute or subacute, optic neuropathy. The typical symptoms include reduced visual acuity and central scotoma. Despite the presence of deep central scotoma, some patients with LHON are able to perform daily activities. This study aimed to investigate the correlation between the residual visual field and visual acuity, critical flicker frequency, and fixation ellipse in patients with chronic LHON. Methods: Residual visual function (defined as sensitivity points where patients sensed the size V stimulus) of both eyes was evaluated in 10 patients with LHON carrying the m.11778 mitochondrial DNA mutation and with median age of onset and disease duration of 29 and 16.5 years, respectively. The central visual field was measured as static perimetry using the Humphrey visual field testing 30-2 program with the size III or V stimulus. Moreover, best-corrected visual acuity, critical flicker frequency, and the correlation between fixation ellipse and residual central visual fields were determined. The analysis was performed through a linear mixed-effects model. Results: The residual visual sensitivity in the inferior nasal visual field was significantly correlated with the logMAR (p < 0.05). The fixation ellipse fell within the residual visual field region with higher sensitivity. Conclusions: Patients with chronic LHON tended to retain the sensitivity detectable with the size V stimulus at the central inferior nasal visual field regions, where the fixation ellipse fell. Visual acuity, which influences daily activity, was spatially correlated with residual visual sensitivity.

The Far Nasal Part of the Field of Vision – Part II – Contribution to the Timely Diagnosis of Glaucoma

Aim: The aim of this study was to examine possible changes in the conventionally undiagnosed nasal visual field in patients diagnosed with early primary open angle glaucoma. Material and Methods: Examination of the far nasal part of the visual field was performed in 30 patients (60 eyes) with early stage of primary open angle glaucoma (preperimetric stage of changes). The cohort consisted of 16 women (mean age 46.5 years) and 14 men (mean age 44.7 years). In all eyes, the glaucoma program (rapid threshold program of 50 degrees nasally and 22 degrees temporally) was performed with the Medmont M700 instrument to determine the physiological visual field. Visual acuity was 1.0 with a possible correction less than or equal to ±3 diopters and they had no other ocular defect except glaucoma disease. The visual field was subsequently examined with the same instrument by moving the fixation point 40 degrees temporally (spatially adaptive program) and simultaneously turning the head 10 degrees nasally. A total of 89 examination points were included using flicker stimuli and a range of 0–120 degrees nasally. Results: The far nasal limit of the visual field reached 100° in 13.33% of eyes, 105° in 20% of eyes and up to 110° in 66.67% of eyes. Conclusion: In all eyes, depression of the distal periphery of the nasal part of the visual field was found to range from 50 to 95 degrees, with a normal visual field examined by the glaucoma program.

Peripheral refraction under different levels of illuminance.

Peripheral refraction is believed to be involved in the development of myopia. The aim of this study was to compare the relative peripheral refraction (RPR) at four different levels of illuminance, ranging from photopic conditions to complete darkness, using an open-field autorefraction method. The RPRwas calculated for each eccentricity by subtracting central from peripheral autorefraction measurements. The study included 114 myopic eyes from 114 subjects (mean age of 21.81 ± 1.91 years) and the mean difference in RPRbetween scotopic and photopic conditions (0 and 300 lux, respectively) was +0.32 D at 30° temporal and +0.37 D at 30° in the nasal visual field (NVF). Statistically significant differences were observed between 0 and 300 lux at 30° in the temporal visual field and at 30° and 20° in the NVF. Our results revealed a significant increase in relative peripheral hyperopia with increasing visual field eccentricity along the horizontal visual field in myopic eyes of young adults. Furthermore, this relative peripheral hyperopia increased as illumination decreased. These findings suggest that an increase in peripheral illuminance may protect against myopic eye growth.

Glaucomatous optic nerve damage in the contralateral eye of a patient with peripapillary retinoschisis: a case report

BackgroundPeripapillary retinoschisis (PPRS) is often associated with glaucomatous eyes. It usually occurs in eyes with a more advanced stage of glaucoma with obvious optic nerve damage. We report a patient who was found to have PPRS in one eye during a routine physical examination without obvious glaucoma symptoms. Further examination revealed glaucomatous visual field loss and retinal nerve fiber layer defects in the contralateral eye.Case presentationA 55-year-old man presented for a routine physical examination. The anterior segment was normal in both eyes. Fundus examination revealed an elevated and red optic disc in the right eye. In addition, scattered patchy red lesions were seen on the retina on the temporal side of the optic disc. The color and boundary of the left optic disc were normal, and the cup-to-disc ratio was 0.6. Optical coherence tomography showed retinoschisis on the optic nerve head of the right eye throughout the entire circumference, extending to the retina on the temporal side of the optic disc. The intraocular pressure was 18 mmHg OD and 19 mmHg OS. The patient was diagnosed with PPRS (OD). However, no optic disc pit or optic disc coloboma was found. Further examination showed that the visual field of the patient’s right eye was generally normal, while a glaucomatous visual field defect was found in the left eye, which manifested as a nasal step visual field defect. Moreover, stereophotography and a red-free fundus image revealed two retinal nerve fiber layer defects in the supratemporal and infratemporal regions of the retina of the left eye. Continuous intraocular pressure measurement found that the intraocular pressure fluctuated between 18 and 22 mmHg OD and 19–26 mmHg OS during the daytime. Primary open-angle glaucoma was then diagnosed.ConclusionsIn this case, we found that PPRS was associated with glaucomatous optic nerve changes and visual field defects in the fellow eye.

Peripheral optical anisotropy in refractive error groups.

This study investigated differences in peripheral image quality with refractive error. Peripheral blur orientation is determined by the interaction of optical aberrations (such as oblique astigmatism) and retinal shape. By providing the eye with an optical signal for determining the sign of defocus, peripheral blur anisotropy may play a role in mechanisms of accommodation, emmetropisation and optical myopia control interventions. This study investigated peripheral through-focus optical anisotropy and image quality and how it varies with the eye's refractive error. Previously published Zernike coefficients across retinal eccentricity (0, 10, 20 and 30° horizontal nasal visual field) were used to compute the through-focus modulation transfer function (MTF) for a 4 mm pupil. Image quality was defined as the volume under the MTF, and blur anisotropy was defined as the ratio of the horizontal to vertical meridians of the MTF (HVRatio). Across the horizontal nasal visual field (at 10, 20 and 30°), the peak image quality for emmetropes was within 0.3D of the retina, as opposed to myopes whose best focus was behind the retina (-0.1, 0.4 and 1.5D, respectively), while for hyperopes it lay in front of the retina (-0.5, -0.6 and -0.6D). At 0.0D (i.e., on the retina), emmetropes and hyperopes both exhibited horizontally elongated blur, whereas myopes had vertically elongated blur (HVRatio=0.3, 0.7 and 2.8, respectively, at 30° eccentricity). Blur in the peripheral retina is dominated by the so-called "odd-error" blur signals, primarily due to oblique astigmatism. The orientation of peripheral blur (horizontal or vertical) provides the eye with an optical cue for the sign of defocus. All subject groups had anisotropic blur in the nasal visual field; myopes exhibited vertically elongated blur, perpendicular to the blur orientation of emmetropes and hyperopes.

Adaptive Features of the Eye to the Ecological Habit of the Short-Eared Owl Asio flammeus and Japanese Scops Owl Otus semitorques

In this study we investigated the eye morphology and retinal topography of two owl species in relation to their visual environment. Although Short-eared Owl Asio flammeus is larger and weighs more than Japanese Scops Owl Otus semitorques, its eye dimensions (weight, corneal diameter, and axial length) are all smaller than the scops owl's. Owl retinas were examined in Nissl-stained whole-mount preparations. The total number of retinal ganglion cells (RGCs) was greater in the Japanese Scops Owl (4,703.0×103 cells) than in the Short-eared Owl (2,346.8×103 cells). The eye morphology of, and the number of RGCs in the Japanese Scops Owl indicate that it is more adapted to a nocturnal habit. An area of high-density RGCs was horizontally distributed in the temporal retina of the Short-eared Owl, with a peak density of 17.4×103 cells/mm2. In the Japanese Scops Owl's temporal retina, there was an oval-shaped arrangement with a peak density of 23.1×103 cells/mm2. These distributions indicate that whereas Short-eared Owl is adapted to open habitats, Japanese Scops Owl is adapted to enclosed habitats. The RGCs of both species were classified into three categories (small, medium, and large) based on the size and appearance of somas. In both species, medium-sized cells predominated, and the proportion of large-sized cells was smallest. The distribution and high-density areas differed among these groups, suggesting adaptation to the visual environment. The high-density areas of these groups cover the nasal visual fields, which include the overlap for binocular vision.

The Relationship between Intracranial Pressure and Visual Field Zones in Normal-Tension Glaucoma Patients.

Growing evidence suggests that intracranial pressure (ICP) plays an important role in the pathophysiology of glaucoma, especially in normal-tension glaucoma (NTG) patients. Controversial results exist about ICP’s relationship to visual field (VF) changes. With the aim to assess the relationship between ICP and VF zones in NTG patients, 80 NTG patients (age 59.5 (11.6) years) with early-stage glaucoma were included in this prospective study. Intraocular pressure (IOP) (Goldmann), visual perimetry (Humphrey) and non-invasive ICP (via a two-depth Transcranial Doppler, Vittamed UAB, Lithuania) were evaluated. Translaminar pressure difference (TPD) was calculated according to the formula TPD = IOP − ICP. The VFs of each patient were divided into five zones: nasal, temporal, peripheral, central, and paracentral. The average pattern deviation (PD) scores were calculated in each zone. The level of significance p < 0.05 was considered significant. NTG patients had a mean ICP of 8.5 (2.4) mmHg. Higher TPD was related with lower mean deviation (MD) (p = 0.01) and higher pattern standard deviation (PSD) (p = 0.01). ICP was significantly associated with the lowest averaged PD scores in the nasal VF zone (p < 0.001). There were no significant correlations between ICP and other VF zones with the most negative mean PD value. (p > 0.05). Further studies are needed to analyze the involvement of ICP in NTG management.

Woman with black floaters in eye.

A 29-year-old female presented to the emergency department with decreased visual acuity and black floaters in the left eye after an insidious progression of a febrile illness with associated myalgias, headaches, and lymphadenopathy over a 4-week period. History revealed she had eaten undercooked venison several weeks before symptom onset. She was afebrile and neurologically intact, without evidence of vitreal or retinal abnormalities on bedside ultrasound. During ophthalmologic follow-up care 2 days later, she developed left nasal visual field deficit. Ophthalmology noted optic disk edema and steroid therapy was initiated for presumed optic neuritis. Subsequent magnetic resonance imaging was negative, and she was referred to a retinal specialist who identified focal active chorioretinitis and confirmed the diagnosis with serum antibody titers (Figure 1). Toxoplasmosis chorioretinitis is one of the most frequent causes of infectious uveitis affecting the posterior segment of the eye, which can cause severe vision loss. The most common cause is ingestion of undercooked meat or water with oocytes.1-3 Infections may be asymptomatic. However, ocular symptoms can occur as a result of initial infection or reactivation of previous infection.4 The classic retinal finding is the “headlight in fog sign” noted by a focal retinitis viewed through vitreous haze.5 Diagnosis is made clinically. Serum antibody titers confirm the diagnosis. A 4- to 6-week course of trimethoprim-sulfamethoxazole is the first-line therapy for sight-threatening lesions. Other scenarios or refractory cases may require regimens of azithromycin, pyrimethamine, atovaquone, leucovorin, glucocorticoids, and/or intravitreal clindamycin injections. Lifelong suppressive antitoxoplasmosis treatment is often necessary to prevent recurrence.6

Frequent self-monitoring of intraocular pressure can determine effectiveness of medications in eyes with normal tension glaucoma: A case report.

It is difficult to follow changes in the intraocular pressure (IOP) in glaucomatous eyes comprehensively because of the limited number of outpatient examinations. We report our findings in a case of normal tension glaucoma (NTG) in which frequent self-measurements of the IOP were used to evaluate the IOP-lowering effect of different medications. A 50-year-old man with NTG had a nasal step visual field defect in his right eye and was being treated with 0.005% latanoprost (LAT) ophthalmic solution (XALATAN®). The patient was diagnosed with NTG. The patient had a mean IOP in the right eye of 10.9 ± 1.5 mm Hg (68 measurements in 1 month, Period A) during treatment with 0.005% LAT ophthalmic solution. During the second month (Period B), the mean IOP in the same eye was 9.8 ± 1.7 mm Hg (59 measurements) with treatment with a LAT and carteolol fixed combination (LCFC). And during the third month (Period C), the mean IOP was 7.4 ± 1.1 mm Hg (57 measurements) on the same right eye after the addition of brimonidine and brinzolamide fixed combination ophthalmic solution to the LCFC ophthalmic solution. Comparisons of the IOPs between Periods A and B and between B and C showed that the reductions in the IOP were significant. We conclude that frequent self-measurements of the IOP can determine that small changes of the IOPs are significant.

A nasal visual field advantage in interocular competition

A nasal visual field advantage in interocular competition

Retinal Detachments Associated With Topical Pilocarpine Use for Presbyopia

To present a case series of retinal detachments associated with the use of pilocarpine for presbyopia. Multicenter case series of 3 eyes from 2 patients. Patient 1, a 47-year-old man, presented with flashes and floaters in both eyes. The patient had started pilocarpine 1.25% drops 1 month prior for presbyopia in both eyes. He noted the onset of flashes and floaters 3 days after he initiated the drops. A dilated examination revealed an inferotemporal retinal detachment in the right eye with an associated retinal tear inferotemporally. The left eye demonstrated a retinal detachment in the superior quadrant with an associated horseshoe tear at 12 o'clock. Patient 2, a 46-year-old man, presented 5 weeks after initiating topical pilocarpine 1.25% drops for presbyopia. He noted a nasal visual field defect in his left eye that progressed to include his central vision. A dilated examination revealed a superior retinal detachment from 11 to 3 o'clock with subretinal fluid extending into the macula. Pilocarpine and other miotics have long been suspected to be associated with an increased risk of retinal detachment. Prior to prescribing pilocarpine for presbyopia, physicians should inform patients of this potential adverse event and consider that these patients undergo a screening dilated examination, particularly if they are myopic, to determine if they are at higher risk for retinal detachment. Before the initiation of therapy, patients should be appropriately informed regarding symptoms of retinal tears or detachment, which include flashes, floaters, and visual field loss.

A nasal visual field advantage in interocular competition

When our eyes are confronted with discrepant images (yielding incompatible retinal inputs) interocular competition (IOC) is instigated. During IOC, one image temporarily dominates perception, while the other is suppressed. Many factors affecting IOC have been extensively examined. One factor that received surprisingly little attention, however, is the stimulus’ visual hemifield (VHF) of origin. This is remarkable, as the VHF location of stimuli is known to affect visual performance in various contexts. Prompted by exploratory analyses, we examined five independent datasets of breaking continuous flash suppression experiments, to establish the VHF’s role in IOC. We found that targets presented in nasal VHF locations broke through suppression much faster than targets in temporal VHF locations. Furthermore, we found that the magnitude of this nasal advantage depended on how strongly the targets were suppressed: the nasal advantage was larger for the recessive eye than for the dominant eye, and was larger in observers with a greater dominance imbalance between the eyes. Our findings suggest that the nasal advantage reported here originates in processing stages where IOC is resolved. Finally, we propose that a nasal advantage in IOC serves an adaptive role in human vision, as it can aid perception of partially occluded objects.