Systematic Review of Machine Learning applied to the Prediction of Obesity and Overweight

Obesity and overweight has increased in the last year and has become a pandemic disease, the result of sedentary lifestyles and unhealthy diets rich in sugars, refined starches, fats and calories. Machine learning (ML) has proven to be very useful in the scientific community, especially in the health sector. With the aim of providing useful tools to help nutritionists and dieticians, research focused on the development of ML and Deep Learning (DL) algorithms and models is searched in the literature. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol has been used, a very common technique applied to carry out revisions. In our proposal, 17 articles have been filtered in which ML and DL are applied in the prediction of diseases, in the delineation of treatment strategies, in the improvement of personalized nutrition and more. Despite expecting better results with the use of DL, according to the selected investigations, the traditional methods are still the most used and the yields in both cases fluctuate around positive values, conditioned by the databases (transformed in each case) to a greater extent than by the artificial intelligence paradigm used. Conclusions: An important compilation is provided for the literature in this area. ML models are time-consuming to clean data, but (like DL) they allow automatic modeling of large volumes of data which makes them superior to traditional statistics.

An ensemble-based approach for automated medical diagnosis of malaria using EfficientNet

Each year, more than 400,000 people die of malaria. Malaria is a mosquito-borne transmissible infection that affects humans and other animals. According to World Health Organization (WHO), 1.5 billion malaria cases and 7.6 million related deaths have been prevented from 2000 to 2019. Malaria is a disease that can be treated if early detected. We propose a support decision system for detecting malaria from microscopic peripheral blood cells images through convolutional neural networks (CNN). The proposed model is based on EfficientNetB0 architecture. The results are validated with 10-fold stratified cross-validation. This paper presents the classification findings using images from malaria patients and normal patients. The proposed approach is compared and outperforms the related work. Furthermore, the proposed ensemble method shows a recall value of 98.82%, a precision value of 97.74%, an F1-score of 98.28% and a ROC value of 99.76%. This work suggests that EfficientNet is a reliable architecture for automatic medical diagnostics of malaria.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11042-022-12624-6.

Macular choroidal thickness: evaluation of variability among measurements and assessment of predictive value of glaucomatous visual field damage

INTRODUCTION

To investigate the relationship between the choroidal circulation and glaucoma, assessing macular choroidal thickness (MCT) as a predictive value of glaucomatous visual field damage.

METHODS

Twenty primary open-angle glaucoma patients were recruited. Patients underwent two SS-OCTs scans: one with DRI OCT (Topcon) and the other with PLEX Elite 9000 (Zeiss). Standard OCT parameters were acquired by DRI OCT, while MCT was manually measured in 5 points on Plex ELITE 9000 images. The relationship among MCT, standard OCT parameters and visual field indices were evaluated. Pearson's r correlation was calculated to evaluate these relationships. Reproducibility of measurements was analyzed.

RESULTS

MCT measurements showed a good intra- and inter-observer repeatability. A negative correlation appeared between MCT and body mass index (BMI) (r = -0.518, p=0.023). Mean deviation showed a statistically significant correlation with MCT measured at sub-foveal and at 1000 µm nasally (r = 0.50, p=0.03 and r = 0.52, p=0.023). A correlation was found between the two MCT (Zeiss vs Topcon) measurements and between MCT and peripapillary choroidal thickness (r = 0.944 and r = 0.740, p<0.001, respectively).

CONCLUSIONS

A good intra- and inter-observer reproducibility was found. MCT showed a weak predictive value of glaucomatous visual field damage. A significant correlation was found between MCT and BMI.

Non-Mydriatic Ultra-Wide Field Imaging Versus Dilated Fundus Exam and Intraoperative Findings for Assessment of Rhegmatogenous Retinal Detachment

Background: to compare the extent of the detached retina and retinal tears location in rhegmatogenous retinal detachment (RRD) among non-mydriatic ultra-wide field (UWF) imaging, dilated fundus exam (DFE), and intraoperative evaluation. Methods: this retrospective chart review comprised 123 patients undergoing surgery for RRD. A masked retina specialist analyzed the UWF fundus images for RRD area, status of the macula, and presence and location of retinal breaks. The same variables were collected from a database including DFE and intraoperative recordings. Evaluation methods were compared. Results: mean age was 59.8 ± 14.9 years. Best-corrected visual acuity improved from 0.25 ± 0.3 (Snellen) to 0.67 ± 0.3 at 12 months (p = 0.009). The RRD description and assessment of macula status (34.5% macula-on) did not differ between UWF, DFE, and intraoperative examination. The inferior quadrant was involved most frequently (41.5%), followed by the superior (38.9%), temporal (27.8%) and nasal quadrant (14.8%). Intraoperative exam detected 96.7% of retinal tears compared with DFE (73.2%, p = 0.008) and UWF imaging (65%, p=0.003). UWF imaging and DFE did not differ significantly. Conclusion: RRD extent on DFE and UWF images was consistent with intraoperative findings. UWF and DFE detection of peripheral retinal tears was similar, but 25% of retinal breaks were missed until intraoperative evaluation.

Changes in Retinal OCT and Their Correlations with Neurological Disability in Early ALS Patients, a Follow-Up Study

BACKGROUND

To compare early visual changes in amyotrophic lateral sclerosis (ALS) patients with healthy controls in a baseline exploration, to follow-up the patients after 6 months, and to correlate these visual changes with neurological disability.

METHODS

All patients underwent a comprehensive neurological and ophthalmological examination. A linear mixed analysis and Bonferroni p-value correction were performed, testing four comparisons as follows: Control baseline vs. control follow-up, control baseline vs. ALS baseline, control follow-up vs. ALS follow-up, and ALS baseline vs. ALS follow-up.

RESULTS

The mean time from the diagnosis was 10.80 ± 5.5 months. The analysis of the optical coherence tomography (OCT) showed: (1) In ALS baseline vs. control baseline, a macular significantly increased thickness of the inner macular ring temporal and inferior areas; (2) in ALS follow-up vs. ALS baseline, a significant macular thinning in the inner and outer macular ring inferior areas; (3) in ALS follow-up vs. ALS baseline, a significant peripapillary retinal nerve fiber layer (pRNFL) thinning in the superior and inferior quadrants; and (4) ALS patients showed a moderate correlation between some OCT pRNFL parameters and Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) score.

CONCLUSION

The OCT showed retinal changes in patients with motoneuron disease and could serve as a complementary tool for studying ALS.

Tear Film Osmolarity, Ocular Surface Disease and Glaucoma: A Review

Glaucoma is the second leading cause of blindness in the world, affecting more than 60 million people globally. In order to reduce the progression of the disease, both medical and surgical treatments are used. Frequent side effects of both treatments include a range of modifications of the ocular surface grouped as the Ocular Surface Disease (OSD), which include Dry Eye Disease (DED). DED and other OSD negatively impact on the success of anti-glaucoma treatments and reduce the adherence to medical therapies. Tear film osmolarity (TFO) is a relatively novel test which has become a hallmark of DED. The aim of this paper was to review the association between OSD, DED and glaucoma in view of published TFO data, and to discuss future fields of research and treatments on the topic of glaucoma iatrogenic damage.

Cross-Linked Hyaluronic Acid as Tear Film Substitute

Purpose: The aim of this review is to clarify the role of cross-linked Hyaluronic acid (HA) molecule as a tear supplement and to define its possible applications in dry eye disease. Methods: Current Literature about HA and its cross-linked derivatives has been examined. Results: HA is superior in increasing the viscosity and stability of the tear film compared with other tear supplements such as polyvinyl alcohol, hydroxypropyl methylcellulose, carboximethyl cellulose and polyethylene glycol. Moreover, HA can be modified in different ways to improve its properties such as molecular weight, viscosity, and hydrophobicity to adapt the new artificial molecule to different aims. Conclusions: The current pharmacological trend is to improve the properties of HA by cross-linking parts of the molecule to achieve better bioavailability and resistence to degradation. In dry eye disease, cross-linked HA as tear supplement seems to provide better ocular comfort than linear HA and is therefore subjected to growing interest and diffusion.

EFFECT OF AN INTRAVITREAL DEXAMETHASONE IMPLANT ON DIABETIC MACULAR EDEMA AFTER CATARACT SURGERY

PURPOSE

To analyze the effects of a dexamethasone intravitreal implant (DEX; Ozurdex 700 μg; Allergan) administered immediately after cataract surgery in diabetic patients.

METHODS

This prospective, single-arm, open label study (NCT01748487 at ClinicalTrials.gov) involved Type 2 diabetic patients with at least mild diabetic retinopathy (DR) who underwent cataract surgery and DEX insertion after phacoemulsification, and intraocular lens implantation were enrolled. Best-corrected visual acuity and central retinal thickness (CRT) measured by spectral-domain optical coherence tomography were recorded at 1 week preoperatively, and 1 week, 1 month, and 3 months after surgery. Adverse events were also recorded.

RESULTS

Twenty-four eyes of 24 patients (17 [70.8%] men; mean age 63.7 ± 8.7 years) with mild nonproliferative DR (41.7%), moderate nonproliferative DR (33.3%), severe nonproliferative DR (16.7%), or treated proliferative DR (8.3%) were selected. After DEX treatment, mean CRT changed from 241.1 μm (95% confidence interval, 227.5-254.6 μm) at baseline to 236.9 μm (95% confidence interval, 223.9-249.9 μm) at 1 week (P = 0.09), 238.9 μm (95% confidence interval, 225.5-252.3 μm) at 1 month (P = 0.44), and 248 μm (95% confidence interval, 232.4-260.8 μm) at 3 months (P = 0.15). No eyes showed a postoperative increase >50 μm in the CRT at any visit. A 10% increase in CRT was found in 8.3% of eyes. Mean best-corrected visual acuity significantly improved from 0.37 (20/50) at baseline to 0.19 (20/30) at 1 week, 0.12 (20/25) at 1 month, and 0.12 (20/25) at 3 months (P < 0.001 for each comparison). Mean intraocular pressure before surgery was 13.8 mmHg, and none of the patients developed an intraocular pressure ≥22 mmHg at any visit. None of the patients developed any serious adverse events during the follow-up.

CONCLUSION

These short-term results suggest that a single DEX injection intraoperatively after phacoemulsification could avoid an increase in CRT after cataract surgery in diabetic patients.

Choroidal thickness measured using swept-source optical coherence tomography is reduced in patients with type 2 diabetes

OBJECTIVE

To compare choroidal thickness between patients with type 2 diabetes (T2D) and healthy controls measured using swept-source optical coherence tomography (SS-OCT).

METHODS

The sample comprised 157 eyes of 94 T2D patients, 48 eyes of which had diabetic macular edema (DME), and 71 normal eyes of 38 healthy patients. Subfoveal (SF) choroidal thickness, and choroidal thickness at 500-μm intervals up to 2500 μm nasal and temporal from the fovea were measured using the SS-OCT. Choroidal thicknesses were compared between groups using Student's t-test. Additionally, Pearson correlations were calculated between diabetes duration, glycosylated hemoglobin (HbA1c) levels, and choroidal thickness.

RESULTS

Mean diabetes duration was 16.6±9.5 years, while mean glycosylated hemoglobin was 7.7±1.3%. Overall, the choroid was significantly thinner in T2D patients. Individuals with DME had reduced choroidal thickness in all measurements, except at 2000 and 2500-μm nasal positions, compared to healthy controls. There was a moderate correlation between choroidal thickness and HbA1c levels in DME patients (SF: r = 0.342; p = 0.017). Diabetes duration did not correlate significantly with choroidal thickness.

CONCLUSION

SS-OCT measurements revealed that the choroid was significantly thinner in T2D patients, moderate non-proliferative diabetic retinopathy patients, and DME patients than in healthy individuals. Further studies are needed to clarify the effect of diabetes on this layer and the relationship between choroidal thickness and DME.

A European Perspective on Costs and Cost Effectiveness of Ophthalmic Combinations in the Treatment of Open-Angle Glaucoma

Purpose

Efficacy, safety, and cost implications are important considerations when choosing an ophthalmic treatment. Fixed-combination glaucoma medications containing brimonidine 0.2% and timolol 0.5%, or dorzolamide 2% and timolol 0.5%, were compared with brimonidine 0.2% and dorzolamide 2% that were used as adjunctive therapy to timolol 0.5%.

Methods

A literature review was conducted to determine the outcome parameters of intraocular pressure reduction and tolerability after 3 months of use of brimonidine or dorzolamide, each together with timolol as a fixed-combination or in concomitant therapy. Modelled cost-minimization and cost-effectiveness analyses were performed to investigate the economic consequences of ophthalmic therapy with brimonidine, dorzolamide, and timolol from a societal perspective.

Results

The literature review found that brimonidine and dorzolamide used as fixed combinations with timolol as well as in adjunctive therapy to timolol were equally effective and safe. Furthermore, in the European countries studied, the fixed combination of brimonidine/timolol represented a less costly option when compared to the fixed combination of dorzolamide/timolol evaluated over both a 3-month and a 12-month horizon.

Conclusions

Brimonidine used as a fixed-combination therapy with timolol provided better cost value than dorzolamide/timolol in all the countries studied. For most countries, the fixed combination of brimonidine and timolol also provided better cost value than adjunctive therapy with brimonidine, which was more cost effective than adjunctive therapy with dorzolamide.

Diagnostic ability of Humphrey perimetry, Octopus perimetry, and optical coherence tomography for glaucomatous optic neuropathy

PurposeTo evaluate and compare the diagnostic accuracy of the Humphrey Field Analyzer (HFA), Octopus perimetry, and Cirrus OCT for glaucomatous optic neuropathy.MethodsEighty-eight healthy individuals and 150 open-angle glaucoma patients were consecutive and prospectively selected. Eligibility criteria for the glaucoma group were intraocular pressure ≥21 mm Hg and glaucomatous optic nerve head morphology. All subjects underwent a reliable standard automated perimetry with the HFA and Octopus perimeter, and were imaged with the Cirrus OCT. Receiver-operating characteristic (ROC) curves were plotted for the threshold values and main indices of the HFA and Octopus, the peripapillary retinal nerve fiber layer thicknesses, and the optic nerve head parameters. Sensitivities at 85 and 95% fixed-specificities were also calculated. The best areas under the ROC curves (AUCs) were compared using the DeLong method.ResultsIn the glaucoma group, mean deviation (MD) was -5.42±4.6 dB for HFA and 3.90±3.6 dB for Octopus. The MD of the HFA (0.966; P<0.001), mean sensitivity of the Octopus (0.941; P<0.001), and average cup-to-disc (C/D) ratio measured by the Cirrus OCT (0.958; P<0.001) had the largest AUCs for each test studied. There were no significant differences among them. Sensitivities at 95% fixed-specificity were 82% for pattern standard deviation of the HFA, 81.3% for average C/D ratio of OCT, and 80% for the MD of the Octopus.ConclusionsHFA, Octopus, and Cirrus OCT demonstrated similar diagnostic accuracies for glaucomatous optic neuropathy. Visual field and OCT provide supplementary information and thus these tests are not interchangeable.

Retinal Sensitivity in Patients with Type I Diabetes without Retinopathy or with Minor Retinal Changes

Objective: To evaluate the ability of short-wavelength automated perimetry (SWAP) for the detection of visual impairment in patients with type I diabetes without retinopathy or with minor retinal vascular changes. Design: Comparative cross-sectional study. Participants: 30 eyes of 30 healthy subjects and 73 eyes of 73 patients with type I diabetes mellitus were studied. Methods: Ophthalmic examination of diabetic patients showed no retinopathy or minimal changes (less than 5 microaneurisms in each eye) with no previous laser treatment. All patients were examined by means of the SWAP 24-2 strategy. Mean Deviation (MD) and Pattern Standard Deviation (PSD) were compared between both groups. Results: There were differences in the clusters of altered points between both groups (p=0.004). SWAP MD was lower in the diabetic group than in the controls (-2.89 dB vs. -0.20 dB, p<0.001). SWAP PSD also differed between both groups (2.50 dB in control group, 3.12 dB in the diabetic group, p=0.003). In the diabetic group, mean period from the onset of diabetes was 12.6±6.7 years and minimal vascular changes were observed in the retina of 18 eyes (24.7%), while 55 had no lesions (75.3%). No differences in SWAP changes were found between patients without and with minimal diabetic retinopathy. Conclusions: Retinal sensitivity assessed by SWAP is depressed in patients with type I diabetes regardless of the presence of retinal vascular changes.

Macular Retinal Ganglion Cell Layer Thickness Is Not Reduced in Patients with Obstructive Sleep Apnea

PURPOSE

To evaluate macular ganglion cell layer (GCL) and ganglion cell-inner plexiform layer (GCIPL) thicknesses in patients with obstructive sleep apnea (OSA) syndrome.

METHODS

73 OSA patients and 67 age-matched controls were consecutively and prospectively enrolled. All participants underwent at least one reliable standard automated perimetry (SAP) and were imaged with spectral-domain optical coherence tomography (OCT) using two different devices. The OCT parameters were compared between groups, and Pearson correlations between main indices of SAP and OCT parameters were calculated.

RESULTS

The pattern standard deviation of SAP was higher in the OSA group (p = 0.001). Mean GCIPL thickness was 82.99 ± 10.30 and 80.78 ± 12.15 µm in the control and OSA groups, respectively (p = 0.25), and GCL thickness was 44.93 ± 11.42 µm in the control group and 48.81 ± 10.85 µm in OSA individuals (p = 0.47). Pearson correlations between the GCIPL-GCL measurements and the main indices of SAP were not significant.

CONCLUSIONS

Neither GCIPL nor GCL thickness were reduced in OSA subjects compared with healthy individuals. Retinal sensitivity evaluated with SAP was however decreased in OSA patients.

Assessment of the retinal nerve fiber layer in individuals with obstructive sleep apnea

Background

The effect of obstructive sleep apnea (OSA) syndrome in the peripapillary retinal nerve fiber layer (RNFL) thicknesses remains unclear. The purpose of this study was to assess RNFL measurements acquired using scanning laser polarimetry (SLP) and optical coherence tomography (OCT) in patients with OSA.

Methods

The sample of this cross-sectional study included 40 OSA patients and 45 age-matched controls, consecutively and prospectively selected. All participants underwent at least one reliable standard automated perimetry (SAP) test, while RNFL measurements were obtained using the SLP and OCT. The OSA group was divided into 3 sub-groups based on the apnea/hypopnea index (AHI): mild, moderate, or severe OSA. SAP, SLP, and OCT outcomes were compared between the control and OSA groups. The relationship between AHI and RNFL parameters was also evaluated.

Results

Age was not different between both groups. Mean deviation of SAP was −0.47 ± 0.9 dB and −1.43 ± 2.3 dB in the control and OSA groups, respectively (p = 0.01). RNFL thickness measured with OCT was similar between groups. OSA patients showed increased nerve fiber indicator (NFI; 20.9 ± 7.9 versus 16.42 ± 7.82; p = 0.01) and decreased superior average (59.74 ± 10.35 versus 63.73 ± 6.58; p = 0.03) obtained with SLP compared with healthy individuals. In the total sample, NFI and AHI were moderately correlated (r = 0.358; p = 0.001). In severe OSA subjects (n = 22), NFI and AHI had a Spearman correlation coefficient of 0.44 (p = 0.04).

Conclusion

RNFL thickness measured with OCT did not differ significantly between groups. Severe OSA was related to a reduction of the RNFL thickness assessed by SLP.

Blindness and Glaucoma: A Multicenter Data Review from 7 Academic Eye Clinics

Purpose

To evaluate frequency, conversion rate, and risk factors for blindness in glaucoma patients treated in European Universities.

Methods

This multicenter retrospective study included 2402 consecutive patients with glaucoma in at least one eye. Medical charts were inspected and patients were divided into those blind and the remainder (‘controls’). Blindness was defined as visual acuity≤0.05 and/or visual field loss to less than 10°.

Results

Unilateral and bilateral blindness were respectively 11.0% and 1.6% at the beginning, and 15.5% and 3.6% at the end of the observation period (7.5±5.5 years, range:1–25 years); conversion to blindness (at least unilateral) was 1.1%/year. 134 eyes (97 patients) developed blindness by POAG during the study. At the first access to study centre, they had mean deviation (MD) of -17.1±8.3 dB and treated intraocular pressure (IOP) of 17.1±6.6 mmHg. During follow-up the IOP decreased by 14% in these eyes but MD deteriorated by 1.1±3.5 dB/year, which was 5-fold higher than controls (0.2±1.6 dB/year). In a multivariate model, the best predictors for blindness by glaucoma were initial MD (p<0.001), initial IOP (p<0.001), older age at the beginning of follow-up (p<0.001), whereas final IOP was found to be protective (p<0.05).

Conclusions

In this series of patients, blindness occurred in about 20%. Blindness by glaucoma had 2 characteristics: late diagnosis and/or late referral, and progression of the disease despite in most cases IOP was within the range of normality and target IOP was achieved; it could be predicted by high initial MD, high initial IOP, and old age.

The relationship between structure and function as measured by OCT and Octopus perimetry

BACKGROUND/AIMS

To determine the structure-function relationship between equivalent visual field areas obtained with the Octopus perimeter (OP), and the peripapillary retinal nerve fibre layer (RNFL) thickness measured with spectral-domain optical coherence tomography (OCT) in healthy individuals and patients with glaucomatous optic neuropathy.

METHODS

Eighty-eight normal subjects and 150 patients with open-angle glaucoma were prospectively recruited. Eligible participants for the glaucoma group were required to have elevated intraocular pressure and glaucomatous optic nerve head morphology. All participants underwent reliable automated perimetry with OP, and optic nerve head imaging with the Cirrus OCT. Principal component analysis of the mean threshold values for the visual field test points were performed independently for each hemifield. Pearson correlations were calculated between visual field regions and RNFL thickness sectors.

RESULTS

Mild to moderate correlations were observed between the visual field regions and the peripapillary RNFL thicknesses. Each visual field region was significantly correlated with more than one RNFL sector, and vice versa. The strongest correlation was observed between the RNFL thickness at 5 and 7 clock-hour positions and the superonasal region of OP (r=0.63).

CONCLUSIONS

Retinal sensitivity evaluated with OP correlated moderately well with the RNFL thickness measured by OCT. There was an overlap of the visual field regions within the optic disc.

Structure-Function Relationship between Frequency-Doubling Technology Perimetry and Optical Coherence Tomography in Glaucoma

Purpose: To assess the relationship between the retinal nerve fibre layer (RNFL) thickness and the frequency-doubling technology perimetry (FDT) outcome. Methods: Sixty-two healthy individuals and 72 glaucoma patients were prospectively selected. All participants underwent a reliable FDT and optical coherence tomography (OCT). Pearson correlations were calculated between the unlogged threshold values of FDT and RNFL thicknesses measured by OCT. Results: Mild to moderate correlations were found between a few points from FDT and RNFL thicknesses in the vertical axis. The nasal superior area of FDT and the RNFL thickness at the 7-o'clock position had the strongest correlation (0.434, p < 0.001). Conclusions: The poor agreement between FDT and OCT parameters suggests that both instruments assess different characteristics of glaucomatous optic neuropathy. The map obtained validates previously reported clinical findings and contributes to a better understanding of the structure-function relationship in glaucoma. © 2014 S. Karger AG, Basel.

Dexamethasone intravitreal implant as adjunct therapy for patients with wet age-related macular degeneration with incomplete response to ranibizumab

PURPOSE

To evaluate the visual and anatomical outcomes of dexamethasone intravitreal implant (DXI; 700 μg, Ozurdex; Allergan, Irvine, California, USA) as adjunctive therapy for patients with refractory wet age-related macular degeneration (AMD).

METHODS

Retrospective review of the medical records of seven patients (seven eyes) who initially responded well to intravitreal ranibizumab but subsequently developed persistent intra/sub-retinal fluid (IRF/SRF) and underwent a single injection of DXI, between May 2012 and May 2013. Two weeks after DXI, the patients continued with their monthly ranibizumab injections. Best corrected visual acuity (BCVA) logarithm of the minimum angle of resolution (logMAR) and central retinal thickness (CRT) were recorded at baseline, 2 weeks, 6 weeks, 3 months and 6 months after DXI injection. Complications were recorded too.

RESULTS

All patients had at least 24 months of ranibizumab treatment. Mean age was 81.5±5.8 years. At baseline, mean BCVA was 0.53±0.13 logMAR (20/70 Snellen) and mean CRT was 273.14±50.94 μm. BCVA did not change significantly after DXI over the follow-up period. However, all eyes had lost fewer than 0.3 logMAR units. Complete resolution of the persistent IRF/SRF was achieved in five eyes (71.4%) at 6 weeks, and remained stable at 3 months. Two weeks after DXI injection, the mean CRT diminished compared with baseline (248.28±31.8 µm; p=0.03) and the greatest reduction was observed at 3 months after DXI injection (241.5±36.6 µm; p=0.04). Progression of lens opacity was detected in one case (50% of phakic eyes). Retreatment with DXI was performed in two eyes.

CONCLUSIONS

DXI appears to be effective in vision stabilisation, decreasing IRF/SRF and improvement of CRT in eyes with refractory wet AMD.

[Finding of retinal nerve fiber layer hypertrophy in ataxia of Charlevoix-Saguenay patients]

PURPOSE/METHODS

To present the neuro-ophthalmology examination in 5 spastic ataxia of Charlevoix-Saguenay (ARSACS) patients showing significant increases in retinal nerve fiber layer (RNFL) thickness.

RESULTS/CONCLUSIONS

All patients showed abnormal visual fields, normal optic discs with increased visibility of RNFL in color stereo-photographs, normal examination with Heidelberg Retina Tomography instrument, and moderate to markedly increased RNFL thickness in Cirrus Optical Coherence Tomography evaluation (average thickness: 119 to 220 microns). We found evidence that RNFL hypertrophy may be an alternative funduscopic finding to the hypermyelinated retinal fibers in previous reports. A revision of ARSACS diagnostic criteria, particularly with regard to retinal alterations, is necessary.

Three-dimensional geometries representing the retinal nerve fiber layer in multiple sclerosis, optic neuritis, and healthy eyes

BACKGROUND

To represent and interpret the three-dimensional (3D) geometry and the distribution of the axonal damage to the retinal nerve fiber layer (RNFL) in patients with multiple sclerosis (MS) compared with healthy subjects. To analyze alterations in RNFL morphology in eyes of MS patients with or without previous episodes of optic neuritis (ON).

METHODS

MS patients (n = 122) and age-matched healthy subjects (n = 108) were enrolled. The Spectralis optical coherence tomography system was used to determine the circumpapillary RNFL thickness. The 768 RNFL thickness measurements were used to evaluate thickness measurements in patients with or without antecedent ON and to design a 3D reconstruction of the RNFL thickness representing the mechanobiologic tissue response to neurodegeneration caused by MS and ON episodes.

RESULTS

RNFL thickness was decreased in MS patients, and was higher in the MS group with previous ON. Statistical analysis and 3D RNFL reconstruction revealed greater damage to the ganglionar cells in the superonasal RNFL area (101.77 µm in MS vs. 125.47 µm in healthy subjects) and in the inferotemporal RNFL (119.05 µm in MS eyes and 149.26 µm in healthy eyes).

CONCLUSIONS

The 3D representation of RNFL thickness based on measurements allows physicians to better observe damage in the temporal areas, especially in patients with previous ON.

[Functional relationship between retinal sensitivity threshold values assessed by standard automated perimetry in glaucoma]

OBJECTIVE

To study the correlation between the sensitivity threshold values of the different points assessed by the Humphrey visual field analyzer (24-2 Swedish interactive threshold algorithm [SITA] standard strategy) in glaucoma patients.

SUBJECTS, MATERIAL AND METHODS

Prospective cross-sectorial study. One-hundred and four eyes of 104 glaucoma patients, defined by the appearance of the optic nerve head, were evaluated. Retinal threshold sensitivity points of standard automated perimetry (SA) with SITA standard 24-2 program were obtained. The upper and the lower hemifields were studied separately. Pearson correlation coefficients were calculated between the mean threshold sensitivity value at each point of the visual hemifield and the rest of the threshold points in the same hemifield.

RESULTS

Perimetric correlation maps between retinal threshold sensitivity values in the same hemifield were obtained. Most of the points showed moderate to high correlations (r≥0.65. P<0.001) with neighboring points and distant points in the same hemifield.

CONCLUSIONS

There is a functional relationship between neighboring and distant points in Humphrey Visual Field Analyzer (SITA Standard 24-2) in glaucoma patients. This correlation is related to the anatomical arrangement of ganglion cell axons. This fact enables perimetric patterns of glaucoma defects to be obtained.

Comparison of Keeler Pulsair EasyEye tonometer and Ocular Response Analyzer for measuring intraocular pressure in healthy eyes

Purpose

To evaluate the relationship between intraocular pressure (IOP) measurements obtained with Pulsair EasyEye (PEE) and Ocular Response Analyser (ORA) in healthy patients.

Methods

Sixty-five eyes from 65 patients underwent a full optometric examination, including central corneal thickness (CCT), and IOP measured with PEE and ORA. Differences between IOP measurements between both tonometers were analyzed. Pearson correlation coefficients between IOP values and ORA corneal biomechanics parameters were also obtained.

Results

Statistically significant differences were found between IOP of PEE (IOPk) and Goldmann-corrected IOP of ORA (IOPg; p = 0.001). IOPk and corneal resistance-corrected IOP of ORA (IOPcc) were also found to differ significantly (p = 0.025). Mean differences between IOPg-IOPk, IOPcc-IOPk and IOPg-IOPcc were 0.71 ± 1.66, 0.70 ± 2.46 and 0.01 ± 1.54 mmHg (mean ± standard deviation), respectively.

Pearson correlation coefficients indicated that IOPk, IOPg, and IOPcc were significantly correlated among them (p < 0.001): r = 0.816 for IOPk-IOPg, r = 0.826 for IOPcc-IOPg and r = 0.587 IOPcc-IOPk. IOPk and IOPg were linearly associated with corneal resistance factor (CRF; r = 0.626 and r = 0.619, respectively) and with CCT (r = 0.531 and r = 0.579, respectively). IOPcc had a linear relationship with corneal hysteresis (CH) (r = −0.482) and similar results were found between CRF and CH (r = 0.841), CRF and CCT (r = 0.681) or between CH and CCT (r = 0.466).

Conclusions

Differences between mean values of IOP measured with PEE and ORA are statistically significant, with ORA tonometer taking higher IOP values than PEE in most of the cases. IOPk, IOPcc and IOPg have, al least, moderate positive linear correlations and ORA biomechanics parameters CRF, CH and CCT have a linear positive relation between them.

Predictive value of retrobulbar blood flow velocities in glaucoma suspects

PURPOSE

To determine whether retrobulbar blood flow (RBF) velocities are predictive of conversion to glaucoma.

METHODS

A total of 262 glaucoma suspects were prospectively selected. Participants had normal visual field, increased intraocular pressure, and glaucomatous optic disc appearance at baseline. Topographic analysis of the optic nerve head was performed using a confocal laser scanning ophthalmoscope and the blood flow velocity of retrobulbar vessels was measured by color Doppler imaging. Conversion to glaucoma was assessed according to the changes in the color-coded Moorfields Regression Analysis (MRA) classification of the confocal laser scanning system during a 48-month follow-up period. Survival curves and hazard ratios (HRs) for the association between RBF parameters and conversion to glaucoma were calculated.

RESULTS

End-diastolic velocity and mean velocity in the ophthalmic artery were reduced in subjects that converted to glaucoma based on MRA (36 individuals, 13.7%), while resistivity (RI) and pulsatility indices were increased in the same vessel. Patients with RI values lower than 0.75 in the ophthalmic artery had a survival rate (MRA-converters versus nonconverters) of 93.9%, whereas individuals with RI values greater than 0.75 had a survival rate of 81.7% (HR = 3.306; P = 0.002).

CONCLUSIONS

Abnormal RBF velocities measured by color Doppler ultrasound may be a risk factor for conversion to glaucoma. An RI value higher than 0.75 in the ophthalmic artery was associated with the development of glaucoma.

Topographic relationship between frequency-doubling technology threshold values

PURPOSE

To study the topographic relationship of retinal sensitivity evaluated by frequency-doubling perimetry (FDT) in healthy subjects and patients with glaucoma.

METHODS

Hundred and thirty-four eyes from 134 subjects (72 patients with glaucoma and 62 healthy controls) were prospectively and consecutively selected. Only one eye of each subject was randomly selected for evaluation. All subjects underwent a full ophthalmic examination and a reliable FDT (full-threshold C-20-5 algorithm). Pearson correlation coefficients between threshold values within the same hemifield were calculated. Maps of related points were plotted according to these correlation coefficients.

RESULTS

In the control group, each FDT location strongly to moderately correlated with the other FDT locations in the same hemifield. In glaucoma subjects, only a few locations significantly correlated with other threshold values in the same hemifield. The strongest correlations were observed between neighbouring locations. The pairs of points with the strongest correlation corresponded to the inferior retinal regions. In general, perimetric maps showed the retinotopic distribution of ganglion cell axons in the retinal nerve fibre layer.

CONCLUSIONS

The statistical correlations between the FDT threshold values in the same visual hemifield objectively highlight the structure-function relationship determined by the anatomic distribution of retinal nervous tissue. This structure is altered in patients with glaucoma.

Retinal nerve fiber hypertrophy in ataxia of Charlevoix-Saguenay patients

PURPOSE

To present full ophthalmologic examination and retinal nerve fiber layer (RNFL) photographs of autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) patients showing significant increases in RNFL thickness compared to healthy subjects, but without myelinated retinal fibers.

METHODS

The study design was observational case series. Ten eyes of five patients with molecular confirmation of ARSACS underwent a full ophthalmologic examination that included clinical history, visual acuity, biomicroscopy of the anterior segment, gonioscopy, Goldmann applanation tonometry, central corneal ultrasonic pachymetry, ophthalmoscopy of the posterior segment, standard automatic perimetry (Humphrey field), simultaneous stereophotographs of the optic disc after mydriasis, a series of five red-free digital fundus photographs for RNFL evaluation, topographic analysis of the optic disc using the Heidelberg retina tomography, and measurement of peripapillary RNFL thickness with Cirrus optical coherence tomography.

RESULTS

All patients showed abnormal visual fields, normal optic discs with a mild to strikingly increased visibility of RNFL in color stereophotographs, normal Heidelberg tomography, and moderate to markedly increased RNFL thickness in Cirrus tomography (average thickness ranging from 119 μm to 220 μm).

CONCLUSIONS

We found evidence of RNFL hypertrophy in ARSACS patients that may have been interpreted as hypermyelinated retinal fibers in previous reports. A revision of ARSACS diagnostic criteria, particularly with regard to retinal alterations, is necessary.

Short-term changes in the optic nerve head and visual field after trabeculectomy

AIMS OR PURPOSE: To evaluate short-term changes in optic nerve head topography and visual field induced by surgical reduction of intraocular pressure.

METHODS

A prospective study was performed on 56 eyes of 56 patients with uncontrolled primary open-angle glaucoma despite maximum medical therapy, which underwent trabeculectomy. Optic nerve head evaluations by means of Heidelberg Retina Tomograph, and visual field tests were performed pre-operatively, and at 3 and 6 months after surgery. Differences in intraocular pressure, visual field indices, and Heidelberg Retina Tomograph parameters were evaluated with the t-test for paired data. A linear regression model was calculated to analyze the relationship between intraocular pressure reduction and visual field changes, and optic nerve head changes.

RESULTS

Mean intraocular pressure decreased from 24.4 ± 5.0 mm Hg to 12.1 ± 3.1 mm Hg (month 3, P<0.001), and 10.6 ± 2.8 mm Hg (month 6, P<0.001) after trabeculectomy. Mean retinal nerve fiber layer thickness (baseline, 0.19 ± 0.034; month 3, 0.24 ± 0.039, P=0.05; month 6, 0.21 ± 0.037, P=0.05) showed a statistical significant change compared with baseline values.

CONCLUSIONS

In this 6-months study, a significant increase in retinal nerve fiber layer thickness was detected after glaucoma filtration surgery.

International vision requirements for driver licensing and disability pensions: using a milestone approach in characterization of progressive eye disease

Objective

Low vision that causes forfeiture of driver’s licenses and collection of disability pension benefits can lead to negative psychosocial and economic consequences. The purpose of this study was to review the requirements for holding a driver’s license and rules for obtaining a disability pension due to low vision. Results highlight the possibility of using a milestone approach to describe progressive eye disease.

Methods

Government and research reports, websites, and journal articles were evaluated to review rules and requirements in Germany, Spain, Italy, France, the UK, and the US.

Results

Visual acuity limits are present in all driver’s license regulations. In most countries, the visual acuity limit is 0.5. Visual field limits are included in some driver’s license regulations. In Europe, binocular visual field requirements typically follow the European Union standard of ≥120°. In the US, the visual field requirements are typically between 110° and 140°. Some countries distinguish between being partially sighted and blind in the definition of legal blindness, and in others there is only one limit.

Conclusions

Loss of driving privileges could be used as a milestone to monitor progressive eye disease. Forfeiture could be standardized as a best-corrected visual acuity of <0.5 or visual field of <120°, which is consistent in most countries. However, requirements to receive disability pensions were too variable to standardize as milestones in progressive eye disease. Implementation of the World Health Organization criteria for low vision and blindness would help to establish better comparability between countries.

Long-term perimetric fluctuation in patients with different stages of glaucoma

AIM

To evaluate the long-term perimetric fluctuation (LF) in patients with different stages of glaucoma according to the Glaucoma Staging System 2 (GSS2).

METHODS

This multicentre retrospective study included 161 eyes of 161 stable glaucoma patients undergoing four visual-field tests (Humphrey SITA-Standard program over the central 24° or 30°) over a 2-year period. For each patient, the stage of the disease was classified according to GSS2. LF was then calculated as the mean of the standard deviations of point-to-point threshold sensitivities in the four repetitions. LF in GSS2 stages was compared using the t test. Results LF progressively increased from stage 0 to stage 4, and then decreased at stage 5. Stage 4 had a peak of 3.19 ± 0.94 dB, with statistically significant differences compared with all the other stages. The lowest LF (1.65 ± 0.60 dB) was found for normal subjects, whereas similar data were found for borderline patients and those at stages 1 and 5 (2.09 ± 0.58, 2.13 ± 0.57 and 2.22 ± 0.89 dB, respectively; p > 0.13). Visual fields with generalised defects had a lower LF (1.90 ± 0.81) than those with mixed (2.84 ± 0.87, p = 0.0003) and localised (2.63 ± 0.72, p = 0.004) defects. Conclusions In this study, the authors showed that the lower the visual-field defect, the lower was LF, except at stage 5 of GSS2. As test-retest changes exceeding LF could represent a sign of progression, the authors suggest that clinicians using this classification system calculate LF, in order to better differentiate true progression from variability.

[Ability of Heidelberg Retina Tomograph III to predict progression in patients with early glaucoma or suspected primary open-angle glaucoma]

PURPOSE

To study the ability of Heidelberg Retina Tomography III (HRT 3) measurements to predict perimetry changes in patients with early glaucoma or suspected primary open-angle glaucoma.

MATERIAL AND METHODS

One hundred and thirty two eyes with early glaucoma or suspected glaucoma with no changes in basal perimetry were prospectively selected and periodically evaluated over five years. The eyes were divided in two groups depending on the presence or absence of progression (changes in glaucoma perimetry). The association between morphometric parameters and baseline HRT 3 indices, glaucoma probability score (GPS) and Moorefield's Regression Analysis (MRA), and perimetry progression were studied using Cox multivariate regression analyses. Kaplan-Meier curves were used to illustrate the results.

RESULTS

Forty-eight eyes (36.36%) showed perimetry progression. Perimetry progression showed higher correlations with the disc area (p = 0.001), the cup area (p = 0.002) and the vertical cup disc area (p = 0.001). Multivariate regression analyses showed that eyes with baseline MRA or baseline GPA changes were at a higher risk of having perimetry abnormalities and a faster progression.

CONCLUSIONS

MRA and GPA indices are useful to predict perimetry progression in patients with early primary open-angle glaucoma or suspected glaucoma. These indices can be used as risk markers of functional progression in glaucoma.

[Relationship between standard automated perimetry and optic nerve head topography performed with the Heidelberg Retina Tomograph]

PURPOSE

To determine the correlations between optic nerve head (ONH) parameters measured with the Heidelberg Retina Tomograph (HRT), and the main outcomes of standard automated perimetry (SAP) in normal, ocular hypertensive, glaucoma suspects and glaucomatous subjects.

METHODS

Four hundred and twenty-three patients were enrolled in the study and classified into four groups depending on baseline intraocular pressure, optic nerve head morphology, and SAP results: 87 normal eyes, 192 ocular hypertensive eyes, 70 glaucoma suspects and 74 glaucomatous eyes. In the different diagnostic groups, Pearson's correlation coefficients were calculated between ONH parameters and mean deviation, pattern standard deviation (PSD), number of altered points in each quadrant of the visual field (superior-nasal, inferior-nasal, superior-temporal and inferior-temporal), number of points altered at different probability levels, and threshold values at each point of SAP.

RESULTS

In the normal and ocular hypertensive groups, only a few weak correlations were found between HRT and SAP parameters. The strength and number of significant correlations increased in the suspected glaucoma group. The glaucoma group had the strongest correlations, particularly between cup/disc ratio and rim/disc ratio with MD (r=0.479) and between rim area and PSD (r=0.444).

CONCLUSIONS

Weak to moderate correlations were found between some ONH parameters obtained with the HRT and SAP results in the glaucoma group.