Macular Scotomas Research Articles

Impact of macular scotoma and tubular vision on oculomotor behavior and performance in visuospatial comparison tasks.

Our aim in this study was to understand how we perform visuospatial comparison tasks by analyzing ocular behavior and to examine how restrictions in macular or peripheral vision disturb ocular behavior and task performance. Two groups of 18 healthy participants with normal or corrected visual acuity performed visuospatial comparison tasks (computerized version of the elementary visuospatial perception [EVSP] test) (Pisella et al., 2013) with a gaze-contingent mask simulating either tubular vision (first group) or macular scotoma (second group). After these simulations of pathological conditions, all participants also performed the EVSP test in full view, enabling direct comparison of their oculomotor behavior and performance. In terms of oculomotor behavior, compared with the full view condition, alternation saccades between the two objects to compare were less numerous in the absence of peripheral vision, whereas the number of within-object exploration saccades decreased in the absence of macular vision. The absence of peripheral vision did not affect accuracy except for midline judgments, but the absence of central vision impaired accuracy across all visuospatial subtests. Besides confirming the crucial role of the macula for visuospatial comparison tasks, these experiments provided important insights into how sensory disorder modifies oculomotor behavior with or without consequences on performance accuracy.

The Role of the Inner Nuclear Layer for Perception of Persisting Tiling Inside a Monocular Scotoma.

We report two patients, one with and one without long-term persistent tiling inside an arcuate macular scotoma. In both cases, the scotoma was caused by a cilioretinal artery occlusion. Both patients were almost identical regarding the location and extent of the scotoma. In both cases, there was a comparable degree of atrophy on optical coherence tomography for the retinal nerve fibre, ganglion cell, and inner plexiform layers. The main difference was the preservation of the inner nuclear layer in the patient with persistent tiling. In this patient, optical coherence angiography demonstrates preserved perfusion of the superior vascular plexus, which was not the case in the patient with the negative scotoma who also had atrophy of the inner nuclear layer. Recreational use of cannabinoid enhanced the intensity of perceived tiling in the relative scotoma of the first patient. A review of the literature suggests that the persistent tiling described in our case is different to teichopsias of retinal or cerebral origin. These data suggest that persistent monocular tiling in a scotoma arises from retinal circuit activity that requires the preservation of the inner nuclear layer. Future research should investigate this functional-structural relationship in other diseases, including glaucoma.

Can positions in the visual field with high attentional capabilities be good candidates for a new preferred retinal locus?

The sustained component of visual attention lowers the perceptual threshold of stimuli located at the attended region. Attentional performance is not equal for all eccentric positions, leading to variations in perception. The location of the preferred retinal locus (PRL) for fixation might be influenced by these attentional variations. This study investigated the relation between the placement of sustained attention and the location of a developed PRL using simulations of central scotoma. Thirteen normally sighted subjects participated in the study. Monocular sustained attention was measured in discrete eccentric locations of the visual field using the dominant eye. Subsequently, a six degrees macular scotoma was simulated and PRL training was performed during eight ten-minutes blocks of trials. After training, every subject developed a PRL. Subjects with high attentional capabilities in the lower hemifield generally developed PRLs in the lower hemifield (n=10), subjects with high attentional capabilities in the upper hemifield developed PRLs in the upper hemifield (n=2) and one subject with similar attentional capabilities in the upper and lower hemifield developed the PRL on the upper hemifield. Analyzed individually, the results showed that 70% of the subjects had a PRL location in the hemifield where high attentional performance was achieved. These results suggest that attentional capabilities can be used as a predictor for the development of the PRL and are of significance for low vision rehabilitation and for the development of new PRL training procedures, with the option for a preventive attentional training in early macular disease to develop a favorable PRL.

Development of Monofixation Syndrome After Extraction of Dense Cataracts.

If the interruption of macular fusion for an extended period of time is the key event that results in the development of monofixation syndrome, then the decreased macular input caused by dense cataracts may cause monofixation syndrome in adults. This study was designed to test this hypothesis. The study design was a retrospective chart review that identified patients with unilateral cataracts at two southern Louisiana medical centers. Patients were assigned to the dense cataract group if a unilateral cataract had been present for at least 3 months and led to a visual acuity of worse than 20/200. Patients in the control group had a unilateral cataract for more than 3 months and visual acuity better than 20/200 in the affected eye. Stereoacuity was assessed using the Titmus or Randot stereo test. A Worth 4-dot test viewed at a distance of 20 feet was used to assess the presence of a macular scotoma. The criteria for monofixation syndrome were met if stereoacuity was less than 60 seconds and the Worth 4-dot test demonstrated central macular scotoma at 20 feet. The dense cataract group's association with monofixation syndrome was statistically significant when compared to the control group (P < .0001). This study adds dense adult-onset cataracts to the list of causes of monofixation syndrome and reduced stereoacuity. A delay in treating dense lens opacities can result in good visual outcome but an inferior binocular visual outcome (poor stereoacuity). [J Pediatr Ophthalmol Strabismus. 2017;54(1):39-42.].

Handwriting with a Preferred Retinal Locus for AMD with Scotomas

Individuals with macular scotomas from age-related macular degeneration frequently have difficulty writing legibly. The purpose of this study was to investigate the causes of this difficulty by documenting the location of the retinal image of the pen used for writing in relation to the scotoma and fixational preferred retinal locus (fPRL). Subjects with macular scotomas from age-related macular degeneration and visually normal age-matched controls wrote words while observing their hand, pen, and text in a scanning laser ophthalmoscope. Scanning laser ophthalmoscope video images were analyzed to find the retinal positions of the subject's scotoma, fixation area, and pen tip. Control subjects placed their fovea and scotoma subjects placed their fPRL on or very close to the pen tip for both cursive writing and printing. Scotoma subjects' written text sloped downward at a greater angle than controls'. Text angle was negatively correlated with fPRL eccentricity, visual acuity, and the amount the scotoma obscured the writing guides. When printing, control subjects placed their fovea precisely in the center of printing box guides, whereas scotoma subjects exhibited highly dispersed placement of the fPRL. The principal finding is that, because the retinal locations of the pen tip and the fPRL or fovea are coincident or very close, the fPRL and fovea are "monitoring" the pen tip and its location on the page. It is the PRL determined by asking subjects to fixate (i.e., the fPRL) that is used when handwriting, not a separate "handwriting" PRL. The poor handwriting performance of those with macular scotomas seems to be primarily caused by difficulty in placing letters in the appropriate location probably because of reduced visual acuity of the fPRL and scotoma obscuration of the area on which to write.

Preferred Retinal Loci Relationship to Macular Scotomas: A10-Year Comparison

Age-related maculopathy is the leading cause of vision loss among adults in developed countries, and its prevalence is expected to double over the next decade (Congdon et al., 2004; Friedman et al., 2004). The two forms of age-related maculopathy--exudative and nonexudative--are capable of affecting the macula, with potential symptoms including decreased contrast sensitivity, decreased visual acuity, abnormal adaptation to the dark, and central or pericentral scotomas (Jager, Mieler, & Miller, 2008). When a central scotoma impairs the ability of the fovea to distinguish detail, one or more preferred retinal loci (PRL) (Schuchard & Raasch, 1992; von Noorden & Mackensen, 1962; White & Bedell, 1990), also known as pseudo-foveas (Guez, Le Gargasson, Rigaudiere, & O'Regan, 1993), naturally develop at eccentric retinal locations and become the new points of fixation. The location of the PRL varies from person to person, as does the ability to maintain steady fixation with the PRL and to use it for reading and activities of daily living (Dalgleish & Naylor, 1963; Fletcher, Schuchard, & Watson, 1999; Timberlake et al., 1986; Whittaker, Budd, & Cummings, 1988). Fletcher and Schuchard (1997) reported the results of a study examining patterns of PRL ability and location relative to macular scotomas. They mapped dense scotomas and determined the location of the PRL in 1,339 eyes in 825 persons with a scanning laser ophthalmoscope during a standard low vision rehabilitation evaluation. Fletcher and Schuchard created a scoring system to measure the pursuit ability, fixation stability, and saccadic ability of the PRL. They determined the characteristics of dense scotomas within 2.5 degrees of the PRL or fovea. Of the 1,339 eyes, 84% (1,130) demonstrated an established PRL, ranging in size from 1.0 degrees to 9.0 degrees in diameter, and 82.5% had a central dense scotoma. The PRL had no dense scotomas on any border in 14.8% of the eyes. It had one, two, or three borders with a dense scotoma in 39.7%, 19.0%, and 9.0% of the eyes, respectively. Ring scotomas, bordering the PRL on four borders, were present in 17.4% of the eyes. Of the eyes with one scotomatous border, most had a field defect located either superior (39.0%) or to the right (33.7%). It was less common for the eyes to have field defects to the left or inferior, with 19.9% and 7.5% of the eyes, respectively. This report presents a 10-year comparison of these previous findings. It examines whether the PRL characteristics of persons with low vision remained steady over the ensuing decade. Changes in PRL and visual field characteristics among persons with low vision over time could have implications for the approaches of low vision rehabilitation professionals to training in eccentric viewing and other rehabilitation techniques. METHODS The study used 271 persons who were referred to the Frank Stein and Paul S. May Center for Low Vision Rehabilitation at California Pacific Medical Center (CPMC) in San Francisco between 2005 and 2007. All consecutive patients with low vision were included in the study, regardless of age, gender, race, and other demographic variables. Participants were excluded only if they lacked the cognitive or physical ability to complete a macular perimetry examination, as determined by the clinical impression of the ophthalmologist. Approval from the institutional review board was obtained from CPMC for the retrospective analyses of charts. As part of the standard low vision rehabilitation evaluation, an ophthalmologist measured visual acuity with the Early Treatment of Diabetic Retinopathy System chart (Ferris, Kassoff, Bresnick, & Bailey, 1982). The characteristics of the scotoma and PRL were measured with a Scanning Laser Ophthalmoscope (SLO; SLO-101, Rodenstock, Dusseldorf, Germany). The SLO was outfitted with a smart microperimetry (MacKeben & Gofen, 2007) program with a gaze-contingent display that automatically monitors eye movements, blinks, and other factors. …

Preferred Retinal Locus—Hand Coordination in a Maze-Tracing Task

Fine manual tasks require coordination of vision, eye movements, and motor control. Macular scotomas from age-related macular degeneration (AMD) may adversely affect this coordination. The purpose of this research was to find whether the preferred retina locus for fixation (fPRL) also guided the hand in performing fine manual tasks and how the fingers, fPRL, and scotomas interacted in task performance. Subjects with bilateral macular scotomas from AMD and normally sighted controls traced an irregular "maze" line pattern with the index finger while viewing their hand and the maze in a scanning laser ophthalmoscope (SLO). Video images from the SLO showing the fingers and maze on the retina during the task were analyzed to produce retinal maps showing the scotoma and bivariate ellipses of fPRL and fingertip retinal positions. Fingertip retinal ellipses surrounded and were approximately centered on the fPRL ellipses. Fingertip retinal bivariate area was positively correlated with fPRL bivariate area and the percent time the fPRL was on the maze was correlated with visual acuity. Maze-tracing accuracy was positively correlated with saccade rate for scotoma subjects. Concentric overlap of fPRL and fingertip retinal ellipses indicates that it is the fPRL that guides the hand in the maze-tracing visuomotor task, just as the fovea guides the fingertip for visually normal subjects. It is likely that factors other than fPRL and scotoma characteristics contribute to poorer maze-tracing performance by scotoma subjects in comparison with controls.

Oculo-motor patterns induced by reading in peripheral vision

There is clear evidence that slower reading in peripheral vision results from shrinkage of the visual span - the number of letters recognized with high accuracy without moving the eyes. Based on this evidence, an ideal-observer model, Mr. Chips (Legge et al., 2002), has been used to simulate saccade planning in reading. This model shows a strong relationship between the size of the visual span and saccade length. One prediction of this model is that reading speed in peripheral vision should be correlated with the saccade length (or more precisely with the horizontal component's length of saccades). This prediction is based on the implicit assumption that regression saccades do not occur too often. We have investigated this issue by measuring eye movements of 34 patients with central field loss (induced by age-related macular degeneration). Patients had to read aloud 14 French sentences displayed in succession (each sentence was displayed on one line). Character size was 3× the individual ETDRS acuity. Each patient had an absolute macular scotoma covering the fovea as assessed by MP1 microperimetry. Ocular data were collected with an Eyelink II eyetracker (500 Hz). The horizontal distribution of fixations was analyzed for each sentence with kernel density estimates. In addition, we assessed whether these distributions contained regions with statistically significant curvature – i.e., regions with a high density of fixations (called clusters hereafter). Results show a high variability of density estimates both within- and between patients: some sentences exhibit very homogeneous distributions while others show clear density peaks. The main finding is that reading speed is significantly slower for sentences that contain fixation clusters compared to sentences without clusters. This relationship between reading speed and the presence of fixation clusters has to our knowledge never been reported and should be taken into account to understand eccentric reading.

Effect of Bilateral Macular Scotomas from Age-Related Macular Degeneration on Reach-to-Grasp Hand Movement

Vision plays a critical role in reaching and grasping objects. Consequently, bilateral macular scotomas from age-related macular degeneration (AMD) may affect reach-to-grasp movements. The purpose of this work was to investigate changes in reach-to-grasp movement dynamics and to relate those changes to the characteristics of subjects' preferred retinal loci (PRL), scotomas, and visual acuities. Three-dimensional positions of the index finger and thumb were recorded while subjects with bilateral scotomas and subjects with normal vision reached for and grasped blocks of three widths at two distances under binocular and monocular viewing conditions. Reach-dynamic parameters and the grip aperture (thumb-index finger distance) were calculated. Retinal locations and sizes of subjects' scotomas and PRLs were mapped with a scanning laser ophthalmoscope. Scotoma subjects' hand trajectories had longer movement durations, lower maximum velocities, and longer visual reaction times than those of control subjects. With monocular viewing, maximum grip aperture (MGA) increased as a function of block width at a significantly higher rate for scotoma subjects than for control subjects. MGA decreased with increasing PRL bivariate normal ellipse area, and visual reaction time increased with decreasing acuity of the eye tested. Compared with normally sighted subjects, subjects with bilateral macular scotomas from AMD have reach-to-grasp movements with longer trajectories, longer visual reaction times, lower velocities, and altered MGA-block width scaling. Visual reaction time and MGA are directly related to PRL characteristics. Deficits in reach-to-grasp movement caused by macular scotomas are greater in degree than those reported by others for real or artificial peripheral scotomas.

Wet versus Dry Age-Related Macular Degeneration in Patients with Central Field Loss: Different Effects on Maximum Reading Speed

To describe new, efficient predictors of maximum reading speed (MRS) in age-related macular degeneration (AMD) patients with central field loss. Type of AMD (wet versus dry) was scrutinized, because this factor seems to offer a promising model of differential visual adaptation induced by different temporal courses of disease progression. Linear mixed-effects (LME) analyses were performed on a dataset initially collected to assess the effect of interline spacing on MRS. MRS was measured with MNread-like French sentences in 89 eyes (64 dry and 25 wet) of 61 patients with AMD. Microperimetry examination was performed on each eye. The eyes were included only if they had a dense macular scotoma including the fovea, to ensure that patients used eccentric viewing. Analyses show the unique contributions--after adjustment for the effects of other factors--of three new factors: (1) MRS was higher for wet than for dry AMD eyes; (2) an advantage of similar amplitude was found for phakic eyes compared with pseudophakic eyes; and (3) MRS decreased when distance between fixation preferred retinal locus (PRL) and fovea increased. In addition, the instantaneous slope of the relationship between scotoma area and MRS was much shallower than reported in two other studies. The four effects improve the ability to predict MRS reliably for AMD patients. The wet/dry difference is a major finding that may result from the different time courses of the two types of disease, thus involving different types of visuomotor and attentional adaptation processes.

Gaze-contingent simulation of retinopathy: Some potential pitfalls and remedies

Many important results in visual neuroscience rely on the use of gaze-contingent retinal stabilization techniques. Our work focuses on the important fraction of these studies that is concerned with the retinal stabilization of visual filters that degrade some specific portions of the visual field. For instance, macular scotomas, often induced by age related macular degeneration, can be simulated by continuously displaying a gaze-contingent mask in the center of the visual field. The gaze-contingent rules used in most of these studies imply only a very minimal processing of ocular data. By analyzing the relationship between gaze and scotoma locations for different oculo-motor patterns, we show that such a minimal processing might have adverse perceptual and oculomotor consequences due mainly to two potential problems: (a) a transient blink-induced motion of the scotoma while gaze is static, and (b) the intrusion of post-saccadic slow eye movements. We have developed new gaze-contingent rules to solve these two problems. We have also suggested simple ways of tackling two unrecognized problems that are a potential source of mismatch between gaze and scotoma locations. Overall, the present work should help design, describe and test the paradigms used to simulate retinopathy with gaze-contingent displays.

Small Effect of Interline Spacing on Maximal Reading Speed in Low-Vision Patients with Central Field Loss Irrespective of Scotoma Size

It has been suggested that crowding, the adverse low-level effect due to the proximity of adjacent stimuli, explains slow reading in low-vision patients with absolute macular scotomas. According to this hypothesis, crowding in the vertical dimension should be released by increasing the vertical spacing between lines of text. However, studies with different experimental paradigms and only a few observers have given discrepant results on this question. The purpose of this study was to investigate this issue with a large number of patients whose macular function was carefully assessed. MP1 microperimetry examination was performed for each low-vision patient. Only eyes with an absolute macular scotoma and no foveal sparing (61 patients with AMD, 90 eyes; four patients with Stargardt disease, eight eyes) were included. Maximal reading speed was assessed for each eye with French sentences designed on the MNREAD test principles. The effect of interline spacing on maximal reading speed (MRS) was significant although small; average MRS increased by 7.1 words/min from standard to double interline spacing. The effect was weak irrespective of PRL distance from the fovea and scotoma area and regardless of whether an eccentric island of functional vision was present within the scotoma. Increasing interline spacing is advisable only for very slow readers (<20 words/min) who want to read a few words (spot reading). Vertical crowding does not seem to be a major determinant of maximal reading speed for patients with central scotomas.

Page mode reading with simulated scotomas: Oculo-motor patterns

This study investigated the relationship between reading speed and oculo-motor parameters when normally sighted observers had to read single sentences with an artificial macular scotoma. Using multiple regression analysis, our main result shows that two significant predictors, number of saccades per sentence followed by average fixation duration, account for 94% of reading speed variance: reading speed decreases when number of saccades and fixation duration increase. The number of letters per forward saccade (L/FS), which was measured directly in contrast to previous studies, is not a significant predictor. The results suggest that, independently of the size of saccades, some or all portions of a sentence are temporally integrated across an increasing number of fixations as reading speed is reduced.

Reading newsprint but not headlines: pitfalls in measuring visual acuity and color vision in patients with bullseye maculopathy and other macular scotomas.

To illustrate the confounding factors when assessing visual acuity and color vision in a patient with a bullseye macular scotoma in one eye and a horseshoe of atrophy sparing the fovea in the fellow eye. Case report. Visual acuity, color vision, and scanning laser ophthalmoscope analysis. The patient with geographic atrophy from age-related macular degeneration in both eyes had visual acuity of 20/40- in the right eye and 20/40+ in the left eye. She reported that she could read newsprint but not news headlines. She could not identify any color plates, but had only minor errors using a color cap (large D-15) test. She had a macular ring scotoma (bullseye scotoma) in the right eye, and a horseshoe-shaped area of atrophy surrounding the fovea in the fellow eye. Scotomas surrounding but sparing the fovea can lead to difficulty reading large letters, because these letters do not fit in the spared foveal region. Care must be taken in measuring visual acuity in these patients so that the testing does not stop when the patient cannot read the largest letters. The presence of scotomas in the central field may not allow the whole figure on color plate testing to be integrated and identified, leading to a possible misdiagnosis of cone dystrophy. Color cap testing avoids this problem.

The use of the scanning laser ophthalmoscope in the evaluation of amblyopia

Purpose: The purpose of this study was to evaluate amblyopic patients with scanning laser ophthalmoscope microperimetry to determine whether the scanning laser ophthalmoscope data provide useful information in our understanding of amblyopia Methods: In this retrospective case series, clinical data of 46 patients with amblyopia were examined after treatment for anisometropic or strabismic amblyopia. Ten normal patients served as controls. All patients were tested with the scanning laser ophthalmoscope for the presence of macular scotomata. Scanning laser ophthalmoscope findings were assessed within each group and between groups. Results: A macular scotoma was found in the amblyopic eye of 25 of 26 anisometropic amblyopic patients and all 20 strabismic amblyopia patients. Twenty of 26 patients with anisometropic amblyopia had a relative scotoma in the nonamblyopic eye. All 20 patients with strabismic amblyopia had a nonamblyopic eye scotoma. None of the control patients had a scotoma in either eye. Several clinical features were correlated to scotoma findings. Conclusions: The scanning laser ophthalmoscope proved to be a useful tool for the assessment of some features of amblyopia. A scotoma was identified in not only the amblyopic eye of each amblyopic patient, but also in almost all of the nonamblyopic, presumably “normal” eyes. Thus, ocular effects of amblyopia may not be strictly limited to the amblyopic eye.

A technique to train new oculomotor behavior in patients with central macular scotomas during reading related tasks using scanning laser ophthalmoscopy: immediate functional benefits and gains retention

BackgroundReading with a central scotoma involves the use of preferred retinal loci (PRLs) that enable both letter resolution and global viewing of word. Spontaneously developed PRLs however often privilege spatial resolution and, as a result, visual span is commonly limited by the position of the scotoma. In this study we designed and performed the pilot trial of a training procedure aimed at modifying oculomotor behavior in subjects with central field loss. We use an additional fixation point which, when combined with the initial PRL, allows the fulfillment of both letter resolution and global viewing of words.MethodsThe training procedure comprises ten training sessions conducted with the scanning laser ophthalmoscope (SLO). Subjects have to read single letters and isolated words varying in length, by combining the use of their initial PRL with the one of an examiner's selected trained retinal locus (TRL). We enrolled five subjects to test for the feasibility of the training technique. They showed stable maculopathy and persisting major reading difficulties despite previous orthoptic rehabilitation. We evaluated ETDRS visual acuity, threshold character size for single letters and isolated words, accuracy for paragraphed text reading and reading strategies before, immediately after SLO training, and three months later.ResultsTraining the use of multiple PRLs in patients with central field loss is feasible and contributes to adapt oculomotor strategies during reading related tasks. Immediately after SLO training subjects used in combination with their initial PRL the examiner's selected TRL and other newly self-selected PRLs. Training gains were also reflected in ETDRS acuity, threshold character size for words of different lengths and in paragraphed text reading. Interestingly, subjects benefited variously from the training procedure and gains were retained differently as a function of word length.ConclusionWe designed a new procedure for training patients with central field loss using scanning laser ophthalmoscopy. Our initial results on the acquisition of newly self-selected PRLs and the development of new oculomotor behaviors suggest that the procedure aiming primarily at developing an examiner's selected TRL might have initiated a more global functional adaptation process.

Resolution of Macular Scotoma After Radial Optic Neurotomy in Central Retinal Vein Occlusion

Radial optic neurotomy was performed on a hypertensive 65-year-old man with decreased vision in the right eye secondary to ischemic central retinal vein occlusion. Three months later, his visual acuity improved to 20/50. There was improvement in disc and macular edema, and reduction in retinal hemorrhages clinically and angiographically. Liquid crystal display microperimetry revealed improvement in fixation stability and macular sensitivity. Radial optic neurotomy appears to be an effective treatment alternative for selected patients with ischemic central retinal vein occlusion, and results in rapid improvement in visual acuity, central fixation, and macular scotoma as measured by a liquid crystal display microperimeter. Liquid crystal display microperimetry is a good and reliable alternative to the scanning laser ophthalmoscope for macular perimetry.

Preferred retinal loci and macular scotoma characteristics in patients with age-related macular degeneration

Many patients with macular scotomas due to age-related macular degeneration do not perceive black spots in the visual field where the scotomas are located. Rather, they describe objects as “vanishing,” “jumping out of nowhere” or “having blurry parts,” or a combination of features. In addition, when the macular scotoma affects the fovea, the visual system uses 1 or more preferred retinal loci (PRLs) as a “pseudofovea” to perform visual tasks. Visual function testing with the scanning laser ophthalmoscope has provided a wealth of information regarding how patients perceive the visual world and how the oculomotor system directs eye movements. This article describes 2 specific functions of the oculomotor system, fixation stability and refixation precision, with data collected from normally sighted people and patients with visual field loss. The implications of the characteristics of PRLs and macular scotomas for clinical testing are discussed.

Use of Scanning Laser Ophthalmoscope Microperimetry in Clinically Significant Macular Edema in Type 2 Diabetes Mellitus

Purpose: We used scanning laser ophthalmoscope (SLO) microperimetry to evaluate scotomas in patients with clinically significant diabetic macular edema (CSME) in type 2 diabetes mellitus. Methods: We studied 19 patients (mean age = 63 years; range, 45–78 years) (19 eyes). SLO microperimetry was performed in all eyes. We divided patients into three groups as follows: dense scotoma, relative scotoma, and no scotoma. The following variables were documented: age; duration of diabetes, hemoglobin A 1c levels; logarithm of the minimum angle of resolution (Log MAR) visual acuity; refractive power; a history of panretinal photocoagulation; presence or absence of proliferative diabetic retinopathy, vitreomacular separation, and cystoid changes; the type of macular edema; and stability of fixation. All variables were compared in the three groups. Results: We identified 4 eyes (21.1%) with dense scotoma, 10 (52.6%) with relative scotoma, and 5 (26.3%) with no scotoma. There were significant differences in log MAR visual acuity among those with dense scotoma (1.4 ± 0.5), relative scotoma (0.6 ± 0.2), and no scotoma (0.2 ± 0.3) ( P < .05), and in the prevalence of cystoid changes, diffuse edema, and unstable fixation among those with dense scotoma (75%, 75%, and 100%, respectively), relative scotoma (20%, 30% and 50%, respectively) and no scotoma (0%, 0% and 0%, respectively) ( P < .05). Conclusions: Macular scotoma was observed by SLO microperimetry in 74% of the patients in this study. A scotoma in CSME is related to the formation of cystoid changes and the type of macular edema. In eyes with CSME in type 2 diabetes mellitus, a scotoma in the macula causes visual acuity impairment and unstable fixation.

Diplopia after limited macular translocation surgery

Purpose: Full macular translocation surgery relocates the fovea away from choroidal neovascularization, inducing significant postoperative torsional diplopia. In “limited macular translocation,” a saline-induced retinal detachment is followed by scleral imbrication with mattress sutures and spontaneous retinal reattachment. In this study, diplopia was characterized in patients treated with limited macular translocation. Methods: Two surgeons performed retinal translocation surgery on 250 patients over an 18-month time span. The extent and direction of the retinal translocation, and the amount and location of scleral imbrication, were recorded. All patients complaining of diplopia were referred for ocular motility evaluation and treatment. Results: Thirteen (5.2%) patients complained of occasional or constant diplopia. Imbricating sutures were placed supero-temporally in all cases. Inferior foveal translocation ranged from 200 to 2115 μm (median, 1750 μm). Visual acuity ranged from 20/40 to 20/400 in the operated eye. Prism-and-cover testing underestimated the strabismus when compared with subjective testing. In 3 patients, there was no shift on alternate-cover testing despite binocular diplopia. Excyclotorsion ranged from 0° to 16°. Diplopia resolved in 10 cases with prism; 3 required an occlusive filter for distortion or aniseikonia. One patient underwent successful strabismus surgery to eliminate dependence on prism glasses. Conclusions: Limited macular translocation only rarely produces symptomatic diplopia. Suprisingly, traditional prism-and-cover testing does not reliably quantify the misalignment. This may result from the combination of a persistent macular scotoma and a repositioned fovea relative to the peripheral retina. Prism therapy is generally satisfactory in the absence of retinal distortion or aniseikonia. (J AAPOS 2001;5:388-94)