Adnan Khan

Corneal Confocal Microscopy: An Imaging Endpoint for Axonal Degeneration in Multiple Sclerosis

PurposenTo evaluate whether corneal confocal microscopy (CCM) detects axonal degeneration and whether this is associated with retinal nerve fiber degeneration and clinical disability in patients with multiple sclerosis (MS).nnnMethodsnTwenty-five patients with MS and 25 healthy control subjects underwent CCM, optical coherence tomography (OCT), and assessment of neurological disability using the expanded disability status scale (EDSS) and MS severity score (MSSS).nnnResultsnIn patients with MS compared with controls, there was a significant reduction in corneal nerve fiber density (CNFD), branch density (CNBD), and length (CNFL). There was no significant difference in CCM parameters between patients with optic neuritis (MS-ON) and without (MS-NON), or between relapsing-remitting (RRMS) and secondary-progressive MS (SPMS). There was significant thinning of the retinal nerve fiber layer (RNFL) in the global, temporal, temporal superior, and temporal inferior quadrants, with no difference between MS-ON and MS-NON. Patients with SPMS compared with RRMS had a significantly lower global, temporal superior, temporal inferior, nasal, and nasal superior RNFL. The EDSS and MSSS correlated significantly with CNBD, nasal, nasal superior, and nasal inferior RNFL and with CNBD and nasal inferior RNFL, respectively.nnnConclusionsnCCM and OCT detect significant corneal and retinal nerve degeneration which relates to the severity of neurological deficits in patients with mild MS.

Visual complications in diabetes mellitus: beyond retinopathy

Diabetic retinopathy is the most common cause of vision loss in people with diabetes mellitus; however, other causes of visual impairment/loss include other retinal and non‐retinal visual problems, including glaucoma, age‐related macular degeneration, non‐arteritic anterior ischaemic optic neuropathy and cataracts. Additionally, when a person with diabetes complains of visual disturbance despite a visual acuity of 6/6, abnormalities in refraction, contrast sensitivity, straylight and amplitude of accommodation should be considered. We review and highlight these visual problems for physicians who manage people with diabetes to ensure timely referral and treatment to limit visual disability, which can have a significant impact on daily living, especially for those participating in sports and driving.

Corneal Confocal Microscopy Detects Corneal Nerve Damage in Patients Admitted With Acute Ischemic Stroke

Background and Purpose— Corneal confocal microscopy can identify corneal nerve damage in patients with peripheral and central neurodegeneration. However, the use of corneal confocal microscopy in patients presenting with acute ischemic stroke is unknown. Methods— One hundred thirty patients (57 without diabetes mellitus [normal glucose tolerance], 32 with impaired glucose tolerance, and 41 with type 2 diabetes mellitus) admitted with acute ischemic stroke, and 28 age-matched healthy control participants underwent corneal confocal microscopy to quantify corneal nerve fiber density, corneal nerve branch density, and corneal nerve fiber length. Results— There was a significant reduction in corneal nerve fiber density, corneal nerve branch density, and corneal nerve fiber length in stroke patients with normal glucose tolerance (P<0.001, P<0.001, P<0.001), impaired glucose tolerance (P=0.004, P<0.001, P=0.002), and type 2 diabetes mellitus (P<0.001, P<0.001, P<0.001) compared with controls. HbA1c and triglycerides correlated with corneal nerve fiber density (r=−0.187, P=0.03; r=−0.229 P=0.01), corneal nerve fiber length (r=−0.228, P=0.009; r=−0.285; P=0.001), and corneal nerve branch density (r=−0.187, P=0.033; r=−0.229, P=0.01). Multiple linear regression showed no independent associations between corneal nerve fiber density, corneal nerve branch density, and corneal nerve fiber length and relevant risk factors for stroke. Conclusions— Corneal confocal microscopy is a rapid noninvasive ophthalmic imaging technique that identifies corneal nerve fiber loss in patients with acute ischemic stroke.

Peripheral neuropathy in patients with multiple sclerosis

Objectives To determine the prevalence and severity of neuropathic pain, sudomotor dysfunction and abnormal vibration perception in patients with MS. Methods 73 patients with MS and 32 age-matched healthy controls underwent assessment of expanded disability severity score (EDSS), DN4 to assess neuropathic pain, electrochemical skin conductance (ESC) to assess sudomotor function and vibration perception threshold (VPT). Results Patients with MS had a higher DN4 score (p < 0.001) with 14% fulfilling the criteria for neuropathic pain elevated VPT (p < 0.001) and lower ESC on the feet (p < 0.001) and hands (p < 0.001) compared to control participants. ESC on the feet (32% of MS patients) and hands (30% of MS patients) were lower, and DN4 (77% of MS patients) and VPT (64% of MS patients) were greater than 2SD of the healthy control values, respectively. EDSS correlated with the number of relapses (r = 0.564, p < 0.001), VPT (r = –0.457, < 0.001) and ESC on the feet (r = –0.268, p = 0.023). Conclusions Patients with multiple sclerosis have evidence of sudomotor dysfunction and elevated vibration perception, which were associated with neurological disability from MS.

Corneal confocal microscopy detects severe small fiber neuropathy in diabetic patients with Charcot neuroarthropathy

The aim of the present study was to identify the extent of small fiber neuropathy in diabetic patients with Charcot neuroarthropathy (CN).

Diagnosing Diabetic Neuropathy: Something Old, Something New

There are potentially many ways of assessing diabetic peripheral neuropathy (DPN). However, they do not fulfill U.S. Food and Drug Administration (FDA) requirements in relation to their capacity to assess therapeutic benefit in clinical trials of DPN. Over the past several decades symptoms and signs, quantitative sensory and electrodiagnostic testing have been strongly endorsed, but have consistently failed as surrogate end points in clinical trials. Therefore, there is an unmet need for reliable biomarkers to capture the onset and progression and to facilitate drug discovery in DPN. Corneal confocal microscopy (CCM) is a non-invasive ophthalmic imaging modality for in vivo evaluation of sensory C-fibers. An increasing body of evidence from multiple centers worldwide suggests that CCM fulfills the FDA criteria as a surrogate endpoint of DPN.