Retinal function in patients with serpiginous choroiditis: a microperimetry study

Compass Fundus-Guided Perimetry in Geographic Atrophy

Purpose

To evaluate compass (CMP), a recently introduced device that combines scanning ophthalmoscopy, automated perimetry, and eye tracking, for fundus-guided perimetry (microperimetry) with the purpose of correlating perimetric retinal sensitivity (PRS) and retinal geographic atrophy (GA) features.

Materials and Methods

A retrospective, cross-sectional study was performed in 56 eyes of 43 patients affected by GA. All patients underwent compass 10-2 perimetry, consisting of a full-threshold visual field on fundus photography and an infrared (IR) image of the central 30° of the retina. Data were exported to an Excel sheet. Binarization with black/white (B/W) variables was applied on the compass photo fundus and matched with visual field scores. Patients underwent autofluorescence (AF) and IR images (Heidelberg, Germany): CMP and Heidelberg IR images were homologated by using GIMP software (https://www.gimp.org), and then atrophic areas were manually measured with the ImageJ program. CMP perimetric grid was overlapped with AF and IR pictures by using GIMP, obtaining composite TIFF images, which were then analyzed with the ImageJ greyscale score (GSS) tool. A hyperautofluorescent halo was identified on the GA edges of some patients. Pearson's correlation between GA size on IR compass and IR Heidelberg and between GSS and PRS values has been calculated; the independent t-test was realized to calculate the correlation between GSS and B/W variables identified on the CMP photo fundus. The Spearman correlation between total deviation and pattern deviation was calculated.

Results

The AUC-ROC score between CMP scores and B/W variables was 93,4%. The Spearman correlation between total deviation and pattern deviation was highly significant (p = 0,00). The correlation between AF GSS values and PRS was significant (p value = 0,00), the correlation between GSS of hyperautofluorescent points and PRS was significant (p value = 0,00), and the correlation between IR GSS and PRS was significant (p value = 0,00). The correlation between AF GSS and B/W variables was significant (p value = 0,002), the correlation between hyperautofluorescent points and B/W was not significant (p value = 0,40), and the correlation between IR GSS and B/W was significant (p = 0,00).

Conclusions

Based on our preliminary results, compass seems to be a reliable, quick, and safe device for the anatomical and functional study of GA. The direct visualization of the visual field on the fundus photography as a background allows a precise assessment and clinical monitoring of this disease.

Microperimetry in age: related macular degeneration

Age-related macular degeneration (AMD) is one of the major causes of visual loss and legal blindness in people over 55. Visual function tests are the cornerstone of visual function investigation and any therapeutic approach to AMD implies, as primary endpoint, the maintenance or improvement of visual function. The progression of visual impairment and the quantification of final residual visual function are currently determined by means of visual acuity quantification. The quantification of high-contrast visual acuity though has many drawbacks and cannot be considered a complete functional examination. Microperimetry is a non-invasive method used to analyse fixation and central visual field defects in a topographic related manner. The introduction of mesopic and more recently scotopic microperimetry, in research and clinical practice of macular disorders, now allows us to better investigate macular function as it strictly relates to macular morphology. We therefore can monitor the functional natural history and quantify the beneficial or detrimental effects of different therapies. The application of microperimetry in clinical studies has provided interesting diagnostic and prognostic information on functional macular changes in AMD patients. The present review brings new updates on the correlation between macular changes, mainly described with optical coherence tomography, and microperimetry changes in patients with AMD.

Reference Clinical Database for Fixation Stability Metrics in Normal Subjects Measured with the MAIA Microperimeter

PURPOSE

The purpose of this study was to establish a normal reference database for fixation stability measured with the bivariate contour ellipse area (BCEA) in the Macular Integrity Assessment (MAIA) microperimeter.

METHODS

Subjects were 358 healthy volunteers who had the MAIA examination. Fixation stability was assessed using two BCEA fixation indices (63% and 95% proportional values) and the percentage of fixation points within 1° and 2° from the fovea (P1 and P2). Statistical analysis was performed with linear regression and Pearson's product moment correlation coefficient.

RESULTS

Average areas of 0.80 deg² (min = 0.03, max = 3.90, SD = 0.68) for the index BCEA@63% and 2.40 deg² (min = 0.20, max = 11.70, SD = 2.04) for the index BCEA@95% were found. The average values of P1 and P2 were 95% (min = 76, max = 100, SD = 5.31) and 99% (min = 91, max = 100, SD = 1.42), respectively. The Pearson's product moment test showed an almost perfect correlation index, r = 0.999, between BCEA@63% and BCEA@95%. Index P1 showed a very strong correlation with BCEA@63%, r = -0.924, as well as with BCEA@95%, r = -0.925. Index P2 demonstrated a slightly lower correlation with both BCEA@63% and BCEA@95%, r = -0.874 and -0.875, respectively.

CONCLUSIONS

The single parameter of the BCEA@95% may be taken as accurately reporting fixation stability and serves as a reference database of normal subjects with a cutoff area of 2.40 ± 2.04 deg² in MAIA microperimeter.

TRANSLATIONAL RELEVANCE

Fixation stability can be measured with different indices. This study originates reference fixation values for the MAIA using a single fixation index.

Fixation Characteristics of Severe Amblyopia Subtypes: Which One is Worse?

PURPOSE

To determine differences in macular sensitivity and fixation patterns in different subtypes of severe amblyopia.

METHODS

This case-control study enrolled a total of 73 male adults, including 18 with pure strabismic severe amblyopia, 19 with pure anisometropic severe amblyopia, 18 with mixed (strabismic plus anizometropic) severe amblyopia, and 18 healthy controls. MP-1 microperimetry was used to evaluate macular sensitivity, location of fixation, and stability of fixation.

RESULTS

Mean macular sensitivity, stability of fixation, and location of fixation were significantly worse in all amblyopia subtypes when compared with healthy controls. Intergroup comparisons between amblyopia subtypes revealed that mean macular sensitivity, stability of fixation, and location of fixation were significantly worse in pure strabismic and mixed amblyopic eyes when compared with pure anisometropic amblyopic eyes.

CONCLUSIONS

Strabismus seems to be a worse prognostic factor in severe amblyopia than anisometropia in terms of fixation characteristics and retinal sensitivity.

Adaptive Optics Imaging of Retinal Photoreceptors Overlying Lesions in White Dot Syndrome and its Functional Correlation

PURPOSE

To quantify retinal photoreceptor density using adaptive optics (AO) imaging and correlate it with retinal tomography, fundus autofluorescence, and retinal sensitivity overlying lesions in various white dot syndromes (WDS).

DESIGN

Prospective cross-sectional study.

METHODS

setting: Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, Nebraska, USA.

STUDY POPULATION

Thirty-five lesions of WDS from 12 patients (19 eyes; mean age: 54.4 ± 15.8 years; 9 female) were analyzed.

INTERVENTION

Macular lesions (≤3 regions of interest/eye), at 2 fixed eccentric loci, were imaged using AO, spectral-domain optical coherence tomography, and fundus autofluorescence. In this study, lesions were defined as active if there was presence of hyperautofluorescence within the lesions. Photoreceptor density was calculated after manual correction and adjustment for axial length. Retinal sensitivity was assessed using microperimetry and correlated with photoreceptor density using Spearman rank correlation test.

OUTCOME MEASURES

Mean retinal sensitivity and photoreceptor density at the WDS lesions.

RESULTS

Mean photoreceptor density was 7331 ± 4628 cones/mm(2) overlying 16 active lesions and 6546 ± 3775 cones/mm(2) overlying 19 inactive lesions (P = .896). Mean retinal sensitivity (9.37 ± 5.34 dB) showed modest correlation with photoreceptor density (ρ = 0.42, P = .03). Retinal sensitivity over lesions with intact inner segment-outer segment (IS-OS) junction was 13.35 ± 3.75 dB and 6.33 ± 4.31 dB over lesions with disrupted IS-OS junction (P = .005).

CONCLUSIONS

AO imaging may allow high-resolution analysis of photoreceptor loss among lesions in WDS. Such microstructural changes may correlate with functional loss.

Static and dynamic retinal fixation stability in microperimetry

OBJECTIVE

To compare static (during a pure fixation task) versus dynamic (during microperimetry) quantification of fixation stability using microperimetry in normal and pathologic eyes, by means of 2 available (clinical and bivariate contour ellipse area [BCEA]) classification methods.

DESIGN

Prospective comparative observational study.

PARTICIPANTS

One hundred and forty-nine eyes (110 patients) with different macular diseases and 171 normal eyes (109 subjects).

METHODS

In all eyes studied, fixation stability was acquired during an isolated fixation task (static fixation) and during microperimetry (dynamic fixation). All fixation data were analyzed and compared by means of a clinical classification and by means of BCEA quantification.

RESULTS

Pathologic eyes were classified as follows: 41 eyes with diabetic macular edema (DME group), 13 eyes with vitreoretinal interface disease, 60 eyes with age-related macular degeneration (AMD group), and 35 eyes with primary open-angle glaucoma. Fixation stability was not uniform among groups according to clinical classification in both static and dynamic modalities (p < 0.0001). AMD group showed larger BCEA areas compared with all other groups (p < 0.0001). All pathologic groups showed more unstable fixation in dynamic fashion according to both clinical and BCEA methods (p < 0.0001). The variation of fixation stability of control group in dynamic task was highlighted only by BCEA analysis (p < 0.0001). A deterioration of retinal fixation according to clinical method matches a significant increase in BCEA areas (p < 0.0001).

CONCLUSIONS

The detection of clinical fixation stability changes improves when acquired in the dynamic modality. BCEA analysis provides more accurate evaluation of fixation stability and may detect minimal quantitative changes of the fixation area. However, a standard clinical classification can also detect changes in fixation stability in pathologic eyes. Both methods are useful tools in the evaluation of fixation stability.

Serpiginous choroiditis and infectious multifocal serpiginoid choroiditis

Serpiginous choroiditis (SC) is a posterior uveitis displaying a geographic pattern of choroiditis, extending from the juxtapapillary choroid and intermittently spreading centrifugally. The choroiditis involves the overlying retinal pigment epithelium, and the outer retina. This intraocular inflammation typically involves both eyes in otherwise healthy, middle-aged individuals with no familial or ethnic predilection. Pathogenesis is unclear; based on limited histopathologic studies, however, favorable response to immunosuppressive agents, and the absence of association with systemic or local infectious or noninfectious diseases, an organ-specific autoimmune inflammation seems likely to be the underlying process. Patients, particularly from tuberculosis-endemic regions, may present with fundus changes simulating SC, but show evidence of active tuberculosis and/or the presence of mycobacterial DNA in the aqueous humor. This has been referred to as serpiginous-like choroiditis, but we prefer the description multifocal serpiginoid choroiditis (MSC). We present the distinguishing features of SC and infectious multifocal serpiginoid choroiditis simulating SC. The distinction is crucial to avoid unnecessarily treating SC with antimicrobial agents. Advances in diagnostic and imaging modalities can help differentiate SC from MSC. Novel local and systemic treatment approaches improve the outcome and preserve vision in SC.

Fundus autofluorescence imaging in posterior uveitis

Although the phenomenon of fundus autofluorescence has been known for decades, it has only recently been recognized as a measure of retinal pigment epithelial function and health. Characteristic fundus autofluorescence patterns have been described in eyes affected by inflammation of the posterior segment, and these patterns have provided insights into the pathogenesis of posterior uveitis entities. In addition, preliminary data indicate that fundus autofluorescence characteristics may serve as markers of disease activity, allow prediction of visual prognosis, and may help determine the adequacy of therapy. We provide an overview of the current state of fundus autofluorescence imaging technology and review our current knowledge of fundus autoflourescence findings and their clinical use in the posterior uveitis entities.

Functional retinal changes measured by microperimetry in standard-fluence vs low-fluence photodynamic therapy in chronic central serous chorioretinopathy

PURPOSE

To evaluate the effect of low-fluence photodynamic therapy (PDT) on central retinal sensitivity and fixation stability as compared with standard-fluence PDT for treating chronic central serous chorioretinopathy (CSC).

DESIGN

Prospective longitudinal follow-up of patients enrolled in a nonrandomized clinical trial of standard-fluence vs low-fluence PDT in chronic CSC.

METHODS

Forty-two eyes (42 patients) with chronic CSC were enrolled; 19 eyes received indocyanine green angiography-guided standard-fluence PDT (50 J/cm(2)) and 23 received indocyanine green angiography-guided low-fluence PDT (25 J/cm(2)). Retinal sensitivity in the central 12 degrees and fixation stability were evaluated by MP-1 microperimeter at baseline and at 3 and 12 months after PDT.

RESULTS

Mean central retinal sensitivity improved significantly at all time points (at 12 months vs baseline P < .01, Tukey-Kramer test), in the standard-fluence group from 11.9 to 14.4 at 12 months, and in the low-fluence-group from 11.8 to 16.3, with a significant difference between the 2 groups (P = .04, t test). Fixation stability did not change in either group (not significant, analysis of variance). At 12 months' follow-up the retinal sensitivity significantly correlated with best-corrected visual acuity in both groups (standard-fluence, r = -0.52, P = .02; low-fluence, r = -0.54, P = .01).

CONCLUSIONS

The study shows a significant improvement in macular sensitivity after PDT in eyes with chronic CSC, with greater efficacy in low-fluence-treated eyes. Microperimetry data suggest that low-fluence PDT may be a good treatment option in patients with chronic CSC.