An Artificial Intelligence Driven Approach for Classification of Ophthalmic Images using Convolutional Neural Network: An Experimental Study.

BACKGROUND: Early disease detection is emphasized within ophthalmology now more than ever, and as a result, clinicians and innovators turn to deep learning to expedite accurate diagnosis and mitigate treatment delay. Efforts concentrate on the creation of deep learning systems that analyze clinical image data to detect disease-specific features with maximum sensitivity. Moreover, these systems hold promise of early accurate diagnosis and treatment of patients with common progressive diseases. DenseNet, ResNet, and VGG-16 are among a few of the deep learning Convolutional Neural Network (CNN) algorithms that have been introduced and are being investigated for potential application within ophthalmology. METHODS: In this study, the authors sought to create and evaluate a novel ensembled deep learning CNN model that analyzes a dataset of shuffled retinal color fundus images (RCFIs) from eyes with various ocular disease features (cataract, glaucoma, diabetic retinopathy). Our aim was to determine (1) the relative performance of our finalized model in classifying RCFIs according to disease and (2) the diagnostic potential of the finalized model to serve as a screening test for specific diseases (cataract, glaucoma, diabetic retinopathy) upon presentation of RCFIs with diverse disease manifestations. RESULTS: We found adding convolutional layers to an existing VGG-16 model, which was named as a proposed model in this article that, resulted in significantly increased performance with 98% accuracy (p<0.05), including good diagnostic potential for binary disease detection in cataract, glaucoma, diabetic retinopathy. CONCLUSION: The proposed model was found to be suitable and accurate for a decision support system in Ophthalmology Clinical Framework.

Efficacy and safety of 'dropless vitrectomy surgery' and comparison of outcomes to standard of care topical therapy.

Objective/Background: To compare the effectiveness of intravitreal injection of triamcinolone acetonide/moxifloxacin (Tri-Moxi) with the standard eye drop regimen for controlling postoperative inflammation, intraocular pressure, infections, macular thickness, and visual acuity (VA) in patients undergoing pars plana vitrectomy for various retinal disorders. Subject/Methods: In this retrospective longitudinal study, patients who underwent vitrectomy using intravitreal Tri-Moxi at the end of surgery (Group 1) were compared with those who received standard topical steroid antibiotics (Group 2) in terms of intraocular inflammation, intraocular pressure, macular thickness based on optical coherence tomography, and visual acuity. Results: In total, 162 consecutive eyes (group 1 [81 eyes]; group 2 [82 eyes]) were included. VA improved by two lines in both groups at 90 days. In Group 1, preoperative VA (logMAR) was 0.92 (0.66) compared to 0.92 (0.75) in Group 2 (p = 1), while at 3 months, it was 0.61 (0.3) and 0.57 (0.3), respectively (p = 0.46). Group 1 showed superior outcomes concerning central foveal thickness. The average central foveal thickness CFT (µm) in group 2 preoperatively was 423 (95) and 348 (63) at 3 months compared to group 1 526 (109) and 306 (108) preoperatively and 3 months, respectively (p = 0.042). There was no statistically significant difference in the rate of elevated intraocular pressure between the two groups or anterior chamber cell reaction severity, and no cases of endophthalmitis were observed in either group. Conclusions: Tri-Moxi is effective after vitrectomy and is not inferior to standard postoperative topical therapy.

Opacification of a scleral-sutured Akreos AO60 intraocular lens in the absence of concurrent or subsequent surgery: a case series.

Scleral-fixated intraocular lenses (SCIOLs) are an increasingly used option to place intraocular lenses in patients with compromised capsules. Akreos A060 is an acrylic hydrophilic lens that is commonly used for patients in need of SCIOL. As with other hydrophilic lenses, the Akreos A060 lens is associated with a risk of developing postoperative opacifications. To date, multiple case reports and case series have documented the development of opacifications in the Akreos A060 lens in the setting of subsequent intraocular surgery, most commonly after surgery involving gas or air, as commonly used in many routine retinal and corneal surgeries. Many theories have been proposed to explain this phenomenon, but none has been confirmed. This short case series presents two patients with Akreos A060 lenses who incidentally developed lens opacification in the absence of concurrent or subsequent intraocular surgery.

Successful management of a rare case of endogenous endophthalmitis from soft tissue (gluteal) abscess.

Endophthalmitis, an ophthalmic emergency carries poor visual prognosis without prompt diagnosis and treatment. Endophthalmitis is often exogenous and rarely endogenous. In this report, we describe a rare case of bacterial endogenous endophthalmitis in an immunocompetent 51-year-old patient due to methicillin-resistant staphylococcus aureus septicemia from a gluteal abscess. Ultrasonography confirmed endogenous endophthalmitis. The patient was treated with immediate intravitreal antibiotic injections, prolonged intravenous antibiotics in association with pars plana vitrectomy, retinal detachment repair and vitreous debris removal. Successful treatment was confirmed with negative blood cultures and a clear vitreous on b-scan ultrasound and fundus photography with improvement of his visual acuity. This case highlights the importance of consideration of rare infectious foci as etiology and prompts treatment for successful resolution of endogenous endophthalmitis.

Optics and Utility of Low-Cost Smartphone-Based Portable Digital Fundus Camera System for Screening of Retinal Diseases.

PURPOSE: To describe optical principles and utility of inexpensive, portable, non-contact digital smartphone-based camera for the acquisition of fundus photographs for the evaluation of retinal disorders. METHODS: The digital camera has a high-quality glass 25 D condensing lens attached to a 21.4-megapixel smartphone camera. The white-emitting LED light of the smartphone at low illumination levels is used to visualize the fundus and limit source reflection. The camera captures a high-definition fundus (5344 × 4016) image on a complementary metal oxide semiconductor (CMO) with an area of 6.3 mm × 4.5 mm. The auto-acquisition mode of the device facilitates the quick capture of the image from continuous video streaming in a fraction of a second. RESULTS: This new smartphone-based camera provides high-resolution digital images of the retina (50° telescopic view) in patients at a fraction of the cost (USD 1000) of established, non-transportable, office-based fundus photography systems. CONCLUSIONS: The portable user-friendly smartphone-based digital camera is a useful alternative for the acquisition of fundus photographs and provides a tool for screening retinal diseases in various clinical settings such as primary care clinics or emergency rooms. The ease of acquisition of photographs from a continuously streaming video of fundus obviates the need for a skilled photographer.

Rationale for the diabetic retinopathy clinical research network treatment protocol for center-involved diabetic macular edema.

OBJECTIVE: To describe the underlying principles used to develop a web-based algorithm that incorporated intravitreal anti-vascular endothelial growth factor (anti-VEGF) treatment for diabetic macular edema (DME) in a Diabetic Retinopathy Clinical Research Network (DRCR.net) randomized clinical trial. DESIGN: Discussion of treatment protocol for DME. PARTICIPANTS: Subjects with vision loss resulting from DME involving the center of the macula. METHODS: The DRCR.net created an algorithm incorporating anti-VEGF injections in a comparative effectiveness randomized clinical trial evaluating intravitreal ranibizumab with prompt or deferred (≥24 weeks) focal/grid laser treatment in eyes with vision loss resulting from center-involved DME. Results confirmed that intravitreal ranibizumab with prompt or deferred laser provides superior visual acuity outcomes compared with prompt laser alone through at least 2 years. Duplication of this algorithm may not be practical for clinical practice. To share their opinion on how ophthalmologists might emulate the study protocol, participating DRCR.net investigators developed guidelines based on the algorithm's underlying rationale. MAIN OUTCOME MEASURES: Clinical guidelines based on a DRCR.net protocol. RESULTS: The treatment protocol required real-time feedback from a web-based data entry system for intravitreal injections, focal/grid laser treatment, and follow-up intervals. Guidance from this system indicated whether treatment was required or given at investigator discretion and when follow-up should be scheduled. Clinical treatment guidelines, based on the underlying clinical rationale of the DRCR.net protocol, include repeating treatment monthly as long as there is improvement in edema compared with the previous month or until the retina is no longer thickened. If thickening recurs or worsens after discontinuing treatment, treatment is resumed. CONCLUSIONS: Duplication of the approach used in the DRCR.net randomized clinical trial to treat DME involving the center of the macula with intravitreal ranibizumab may not be practical in clinical practice, but likely can be emulated based on an understanding of the underlying rationale for the study protocol. Inherent differences between a web-based treatment algorithm and a clinical approach may lead to differences in outcomes that are impossible to predict. The closer the clinical approach is to the algorithm used in the study, the more likely the outcomes will be similar to those published. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

A review: role of ultraviolet radiation in age-related macular degeneration.

Age-related macular degeneration (AMD) is a leading cause of blindness in the western world. The retina is highly susceptible to photochemical damage from continuous exposure of light and oxygen. The cornea and the lens block a major portion of the ultraviolet (UV) radiation from reaching the retina (<295 nm). The relationship between UV light exposure and AMD is unclear, although short wavelength radiation and the blue light induce significant oxidative stress to the retinal pigment epithelium. Epidemiologic evidence indicates a trend toward association between severity of light exposure and AMD. In this review, we discuss type 1 and type 2 photochemical damage that occurs in response to UV exposure. We examine the impact of different doses of exposure to UV radiation and the subsequent production of oxidative stress in AMD. Local and systemic protective mechanisms of the retina including antioxidant enzymes and macular pigments are reviewed. This article provides a review of possible cellular and molecular effects of UV radiation exposure in AMD and potential therapies that may prevent blindness resulting from this disease.

Successful delivery of subretinal aflibercept (new surgical technique) for the treatment of submacular hemorrhage in idiopathic polypoidal choroidal vasculopathy.

Submacular hemorrhage (SMH) is often a result of trauma, wet age-related macular degeneration or IPCV and frequently leads to blindness secondary to extreme toxicity of hemoglobin products on photoreceptors. We describe a new technique of subretinal aflibercept injection during pars plana vitrectomy for the treatment of SMH in idiopathic polypoidal choroidal vasculopathy (IPCV). A 55-old male presented with sudden loss of vision (HM) secondary to massive subretinal hemorrhage associated with IPCV. Subretinal injection of aflibercept with a 25 g/42 g cannula coupled to the viscous fluid control unit of a standard vitrectomy system was performed during parsplana vitrectomy. Controlled injection of aflibercept intra-operatively has resulted in a resolution of SMH (confirmed with OCT and ICG). Visual acuity improved from HM to 20/20. This combined approach delivered anti-VEGF agent to target tissue in controlled fashion with the assistance of VFC system (similar to gene therapy) and restored full vision with resolution of SMH.

Successful repair of spontaneous indirect bilateral carotid-cavernous fistula with coil embolization.

Bilateral carotid-cavernous fistula (CCF) is a rare disease process, which portends poor visual outcome with delayed diagnosis and treatment. An 82-year-old woman presented with sudden onset of proptosis and decreased vision. A complete ophthalmologic examination along with magnetic resonance (MR) imaging of the brain and orbits, and MR angiography and venography of the brain confirmed the diagnosis of bilateral CCF. Diagnostic cerebral angiogram with concurrent coil embolization of the right cavernous sinus via left superior ophthalmic vein approach was performed. Bilateral indirect CCFs (type D CCF on the right and a type B CCF on the left) regressed completely after unilateral coil embolization. Visual acuity and limitation in extraocular movements significantly improved with complete resolution. In summary, we describe successful management of bilateral concurrent CCF with image-guided embolization and immediate recovery of vision and resolution of ophthalmological symptoms including proptosis and diplopia.

Pembrolizumab dramatically resolves choroidal metastatis from esophageal adenocarcinoma and restores vision: a case report.

Esophageal adenocarcinoma historically is an aggressive cancer with poor long-term survival. Ocular metastasis secondary to gastrointestinal malignancy is rare. In managing patients with ocular metastasis, quality of life (specifically vision preservation) is one of the most important factors patients and providers consider when deciding on a treatment regimen. Anti-programmed cell death-1 (PD-1) and PD-1 ligand (PD-L1) inhibitors such as pembrolizumab have shown promising results as second-line therapy for patient with metastatic malignancy. We describe a novel case of a functionally monocular patient with known metastatic esophageal adenocarcinoma who developed poor vision and a large choroidal lesion in his better seeing eye. The lesion regressed and vision restored to 20/20 after treatments with pembrolizumab in this case report.

Bevacizumab therapy normalizes the pathological intraocular environment beyond neutralizing VEGF.

PURPOSE: Vascular endothelial growth factor (VEGF) plays a key role in neovascularization by stimulating the proliferation and migration of vascular endothelial cells. The anti-VEGF therapy bevacizumab acts by binding to VEGF and preventing its effects. However, this linear interaction represents only a partial view of the pathobiology of neovascular diseases and the anti-VEGF treatment. To obtain an integrated view of the processes involved in VEGF-related ocular pathologies, we applied a systems approach and investigated whether intravitreal bevacizumab injections have a global effect in normalizing the ocular physiology perturbed by the disease. METHODS: We analyzed 90 analytes representing various pathophysiological processes in aqueous humor. The samples were obtained from eight patients receiving intravitreal bevacizumab injections for various ocular VEGF-related conditions. The samples were obtained before and after the injection and were analyzed using microbead technology developed by Luminex xMAP. RESULTS: Forty-three analytes were detected above the sensitivity of the assay both in pre- and post-injection samples. Of these, normal values of 41 analytes were known and these analytes were further analyzed. The detected analytes included relevant markers such as VEGF, C reactive protein, glutathione, and cytokines. We identified 24 markers that were perturbed more than 1.5 fold in diseased samples (pre-injection) compared to normal levels. The levels of perturbed analytes were compared in post-treatment samples. The results demonstrated an unequivocal trend toward normalization in post-treatment samples. CONCLUSIONS: Our results show intraocular bevacizumab injections change the perturbed physiologic environment of the eye toward normalization. Its effects reached beyond neutralizing VEGF. The results also demonstrate that large-scale analysis of the aqueous, using a systems approach, could provide useful insight regarding ocular diseases, their pathophysiologies, and treatment responses.

Bevacizumab neutralizes the protective effect of vascular endothelial growth factor on retinal ganglion cells.

PURPOSE: Vascular endothelial growth factor (VEGF) is well known for its role in pathologic neovascularization, including wet age-related macular degeneration. However, a growing body of evidence indicates that VEGF is also neuroprotective of non-vascular cells in various animal models through reduction of oxidative stress. In light of the widespread use of intraocular anti-VEGF therapies for age-related macular degeneration (AMD), we evaluated the impact of anti-VEGF agents on the neuroprotective effect of VEGF on retinal ganglion cells. METHODS: Staurosporine differentiated retinal ganglion cells were treated with increasing doses of VEGF in the presence of hydrogen peroxide. After optimization, an increasing concentration of bevacizumab was added to neutralize VEGF-mediated protection. The degree of oxidative damage was measured at various time points using buthionine sulfoxime (BSO), a glutathione reductase inhibitor. Cell viability was assessed using WST-1 and Crystal violet assays. RESULTS: VEGF (200 ng/ml) protected differentiated retinal ganglion cells (RGC)-5 against H(2)0(2)-mediated oxidative stress. This effect was eliminated by co-treatment with bevacizumab (2.0 mg/ml), which by itself was not cytotoxic. CONCLUSIONS: These results indicate an important role for VEGF in the maintenance of retinal ganglion cells.

Ultra wide field angiography documented peripheral retinal eovascularization as cause of vitreous hemorrhage after scleral buckle surgery.

We describe an unusual case of ultra wide fluorescein angiography (UWFA) documented peripheral retinal neovascularization (NVE) with delayed vitreous hemorrhage after placement of an encircling scleral buckle (a common procedure for repair of retinal detachment). Anterior segment ischemia is a rare complication after scleral buckle surgery for the treatment of retinal detachment and results from altered choroidal flow through the impingement of the anterior and long posterior ciliary arteries. UWFA performed for the evaluation of vitreous hemorrhage confirmed ischemia anterior to the scleral buckle and consequential NVE. This case represents the utility of UWFA in evaluating and managing this exceptionally rare complication associated with a common procedure in the field of vitreoretinal surgery.

Allergic fungal sinusitis masquerading as cavernous sinus thrombosis.

Allergic fungal sinusitis (AFS), a noninvasive form of fungal sinusitis, is rarely seen in immunocompetent patients. Involvement of sphenoid sinus can result in proptosis and loss of vision. We report AFS masquerading as posterior cavernous sinus syndrome. A 59-year-old African-American man presented with right complete ptosis with ophthalmoplegia. After an initial work-up and imaging studies, patient underwent endonasal sphenoid surgery, which revealed characteristic 'allergic fungal mucin'. Cavernous sinus syndrome is a rare presenting clinical feature of allergic fungal sinusitis. Ophthalmologists should be aware of this rare presentation of relatively common otorhinological disease for timely referral and appropriate management.

Multimodal Imaging Characteristics of ADRP in a Family with p.Thr58Arg Substituted RHO Mutation.

BACKGROUND: Autosomal dominant retinitis pigmentosa (adRP) is a rare cause of progressive visual impairment in young patients and is frequently a result of RHO gene mutations. p.Thr58Arg rhodopsin mutation leads to misfolding of rhodopsin, subsequent accumulation in the endoplasmic reticulum, and leads to consecutive atrophy of photoreceptor cells through apoptosis. MATERIALS AND METHODS: We describe multimodal imaging findings in a 58-year-old female with adRP due to a c.173 C > G, p.Thr58Arg rhodopsin mutation (confirmed on genotyping), including ultra-wide-field fundus autofluorescence (UWF-FAF), color scanning laser ophthalmoscopy, structural optical coherence tomography (OCT), OCT-angiography (OCT-A), electroretinography (ERG), and visual field testing (HVF). Additionally, we compare the patient's phenotypic findings to those of her offspring, who was also affected by adRP. RESULTS: The 58-year-old female and her son with symptoms of nyctalopia and decreased vision showed macular pigmentary changes in a bull's-eye pattern along with bone spicules in periphery with retinal atrophy. Genotyping confirmed p.Thr58Arg rhodopsin mutation. Wide area of dystrophic retina was noted on UWF-FAF, along with corresponding atrophy of photoreceptor layer on OCT. OCTA revealed complete nonperfusion of the superficial capillary plexus in areas of retinal dystrophy. ERG revealed increased latency and decreased amplitudes; HVF revealed constriction of visual fields consistent with retinal findings. CONCLUSIONS: Multimodal imaging is extremely helpful in delineating the extent of retinal dystrophy and comparable to ERG for monitoring of progress in retinitis pigmentosa. Photoreceptor layer thickness (measured with OCT) strongly correlated with ERG and can be used as a secondary surrogate for monitoring the disease progress.

Successful repair of combined tractional and rhegmatogenous retinal detachment with pars plana vitrectomy without scleral buckle in severe Behçet's disease.

Behçet's disease (BD) is a multisystemic, immune-mediated occlusive vasculitis of unknown etiology with a chronic, relapsing remitting course. Ocular involvement is characterized by recurrent nongranulomatous uveitis with necrotizing obliterative vasculitis affecting both the anterior and posterior segments of the eye and often leads to blindness. We describe successful surgical management of a rare case of combined rhegmatogenous retinal detachment (RRD) and tractional retinal detachment (TRD) in a patient with Behçet's disease. A 28-year-old Hispanic women with known Behcet's disease presented with loss of vision of both eyes. She was found to have extensive bilateral necrotizing vasculitis with severe ischemia. Despite aggressive antivascular endothelial growth factor (VEGF) therapy and pan retinal photocoagulation, patient progressed to total blindness from development of combined rhegmatogenous and tractional funnel retinal detachment. Small gauge pars plana vitrectomy (PPV) with silicone oil tamponade was performed for retinal detachment repair (without scleral buckle). Combined RRD and TRD was successfully treated with standard PPV with silicone oil placement without use of scleral buckle. Visual acuity 1 year postoperatively improved from ability to perceive light to 20/400. Combined forms of retinal detachment, a rare development in Behçet's disease may be effectively treated with PPV (without scleral buckling) with favorable visual and anatomic outcomes.

Multiplex immunoassay analysis of biomarkers in clinically accessible quantities of human aqueous humor.

PURPOSE: Aqueous humor is intimately related to the cells of the anterior and posterior chambers, which affect its composition. Aqueous analysis provides useful information regarding physiological and pathophysiological processes in the eye. Human aqueous samples are typically less than 100 microl, limiting the usefulness of the analysis with traditional Enzyme-Linked immunoSorbant Assay (ELISA) techniques. The specific aim of this study was to investigate if whether large numbers of analytes can be identified in clinically available samples of aqueous humor and to document the detectability of certain biomarkers in the aqueous. METHODS: We used a technology developed by Luminex xMAP to analyze hundreds of analytes in a small sample. Aqueous from eight normal and two diabetic patients was analyzed. RESULTS: Of the 90 analytes evaluated, 52 (57%) were detectable in the normal aqueous. To place these results in biological context, we analyzed the list of expressed analytes using the MetaCore database. The functional pathways, networks, biological processes, and disease processes that these analytes represented were identified. Several ocular pathology-related processes were represented in the aqueous. The detected analytes represented biomarkers of several relevant disease processes including vascular diseases, arteriosclerosis, ischemia, necrosis, and inflammation. To provide the proof of principle that the aqueous profile could offer useful information about the pathophysiological processes, we analyzed two aqueous samples from diabetic patients. These limited samples showed the differences between normal and diabetic samples, including those relevant to diabetic retinopathy such as vascular endothelial growth factor (VEGF), C reactive protein, glutathione, and cytokines. Several biomarker groups for disease processes relevant to diabetes were perturbed. CONCLUSIONS: These results demonstrate that multiplex analysis of the aqueous can be a useful tool in screening for any pathophysiological changes of the ocular environment. Moreover, ocular pathology/pathophysiology-specific Multi-analyte profiles MAPs can be developed and used to analyze the aqueous.

Comparative efficacy of topical tetraVisc versus lidocaine gel in cataract surgery.

BACKGROUND: To compare the clinical efficacy of lidocaine 2% with tetracaine 0.5% for cataract surgery. METHODS: In a randomized, multi-surgeon, controlled clinical trial,122 consecutive cataract cases eligible for topical anesthesia, were randomly assigned to receive lidocaine 2% gel (1 ml) or tetracaine solution 0.5% (TetraVisc, 0.5 ml) before clear corneal phacoemulsification. Main outcome measure was visual analog scale (0 to 10), which was used to measure intra-operative pain. Secondary outcome measures included patients' discomfort due to tissue manipulation and surgeon graded patients' cooperation. Duration of surgery and intra-operative complications were also recorded. RESULTS: The mean age in TetraVisc (TV) group was 70.4 years and in the lidocaine gel group (LG) it was 70.6 years (p = 0.89). Patient reported mean intra-operative pain scores by visual analog scale were 0.70 +/- 0.31 in TV group and 1.8 +/- 0.4 in LG group (P < 0.001). Mean patient cooperation was also marginally better in the TV group (8.3 +/- 0.3) compared to LG group (8.4 +/- 0.6) (P = 0.25). 96% of patients in TV group showed intra-operative corneal clarity compared to 91% in LG group. TV group had less (1 out of 61 patients, 1.6%) intra-operative complications than LG group (3 out of 61 patients, 4.8%). No anesthesia related complications were noted in either group CONCLUSION: Topical TetraVisc solution was superior to lidocaine 2% gel for pain control in patients undergoing clear corneal phacoemulsification. Lidocaine 2% gel is similar to TetraVisc in patient comfort and surgeon satisfaction. TRIAL REGISTRATION: Clinical trials number: ISRCTN78374774.

Values for macular perimetry using the MP-1 microperimeter in normal subjects.

PURPOSE: To establish values for the fixation pattern and macular sensitivity to light in healthy subjects using the MP-1 microperimeter (Nideck Technologies, Vigonza, Italy). METHOD: A prospective study of 37 healthy subjects (age: 19-71 years), approved by the institutional review board. Full-threshold microperimetry of the central 12 degrees of the retina (the macula) was performed prospectively, utilizing 16 points with the MP-1. The fixation stability was simultaneously recorded during microperimetry testing. The relationship between the fixation pattern and light sensitivity with age was calculated using linear regression analysis. RESULTS: Microperimetry was performed on 66 eyes. Total mean sensitivity was 18.33 dB (range: 13.0-19 dB). Mean macular sensitivities at 2 degrees , 4 degrees and 6 degrees as measured by the MP-1 were 18.4+/-2.0, 18.2+/-2.3 and 18.2+/-2.1 dB, respectively. The linear regression analysis revealed a 0.019240, 0.0248 and 0.0285 dB per year age-related decline in mean macular sensitivity at 2 degrees, 4 degrees and 6 degrees from the center of the macula, respectively. The total mean fixation stability values within 2 degrees and 4 degrees were 86 and 96%, respectively. The linear regression analysis also revealed a 0.344% and 0.122% per year decline in age-related fixation stability within 2 degrees and 4 degrees , respectively. There were no statistically significant differences between the median retinal sensitivity or fixation stability values for sex or race in the study. CONCLUSIONS: The MP-1 may be a reliable tool to measure macular sensitivity. Among normal healthy subjects, there was a linear decline in light sensitivity with increasing age.