Corneal nerves anatomy, function, injury and regeneration.

The cornea is a highly innervated tissue, exhibiting a complex nerve architecture, distribution, and structural organization. Significant contributions over the years have allowed us to come to the current understanding about the corneal nerves. Mechanical or chemical trauma, infections, surgical wounds, ocular or systemic comorbidities, can induce corneal neuroplastic changes. Consequently, a cascade of events involving the corneal wound healing, trophic functions, neural circuits, and the lacrimal products may interfere in the corneal homeostasis. Nerve physiology drew the attention of investigators due to the popularization of modern laser refractive surgery and the perception of the destructive potential of the excimer laser to the corneal nerve population. Nerve fiber loss can lead to symptoms that may impact the patient's quality of life, and impair the best-corrected vision, leading to patient and physician dissatisfaction. Therefore, there is a need to better understand preoperative signs of corneal nerve dysfunction, the postoperative mechanisms of nerve degeneration and recovery, aiming to achieve the most efficient way of treating nerve disorders related to diseases and refractive surgery.

Corneal nerves in health and disease.

The cornea is the most sensitive structure in the human body. Corneal nerves adapt to maintain transparency and contribute to corneal health by mediating tear secretion and protective reflexes and provide trophic support to epithelial and stromal cells. The nerves destined for the cornea travel from the trigeminal ganglion in a complex and coordinated manner to terminate between and within corneal epithelial cells with which they are intricately integrated in a relationship of mutual support involving neurotrophins and neuromediators. The nerve terminals/receptors carry sensory impulses generated by mechanical, pain, cold and chemical stimuli. Modern imaging modalities have revealed a range of structural abnormalities such as attrition of nerves in neurotrophic keratopathy and post-penetrating keratoplasty; hyper-regeneration in keratoconus; decrease of sub-basal plexus with increased stromal nerves in bullous keratopathy and changes such as thickening, tortuosity, coiling and looping in a host of conditions including post corneal surgery. Functionally, symptoms of hyperaesthesia, pain, hypoaesthesia and anaesthesia dominate. Morphology and function do not always correlate. Symptoms can dominate in the absence of any visible nerve pathology and vice-versa. Sensory and trophic functions too can be dissociated with pre-ganglionic lesions causing sensory loss despite preservation of the sub-basal nerve plexus and minimal neurotrophic keratopathy. Structural and/or functional nerve anomalies can be induced by corneal pathology and conversely, nerve pathology can drive inflammation and corneal pathology. Improvements in accuracy of assessing sensory function and imaging nerves in vivo will reveal more information on the cause and effect relationship between corneal nerves and corneal diseases.

Long-term corneal subbasal nerve plexus regeneration after laser in situ keratomileusis.

PURPOSE: To analyze the recovery of the subbasal nerve plexus in corneas treated with laser in situ keratomileusis (LASIK) at least 10 years prior compared with nonoperated corneas. SETTING: Clínica Novovisión, Madrid, Spain. DESIGN: Prospective nonrandomized observational study. METHODS: Eyes that had LASIK surgery at least 10 years before (LASIK group) were compared with nonoperated healthy eyes (control group). The subbasal nerve plexus morphology (main nerves density, nerve length, nerve branches density, grade of nerve tortuosity, and reflectivity) and the dendritic cell density from the confocal images obtained with the Heidelberg Retina Tomograph II were analyzed. RESULTS: The study comprised 47 eyes (27 eyes in the LASIK group and 20 eyes in the control group). The values were significantly lower in the LASIK group compared with the control group in main nerves density (9.15 nerves/mm2 ± 3.46 [SD] versus 11.75 ± 2.86 nerves/mm2; P = .009) and nerve branches density (2.96 ± 1.99 nerves/mm2 versus 5.35 ± 3.05 nerves/mm2; P = .002). No significant differences were found in nerve length, grade of nerve tortuosity, dendritic cell density, or subbasal nerve plexus reflectivity between the two groups. CONCLUSIONS: The outcomes suggested that the subbasal corneal nerve plexus did not completely recover its preoperative pattern at least 10 years after LASIK. Both main nerves density and nerve branches density continued to be significantly lower compared with virgin corneas after a mean 13-year follow-up, although other parameters of nerve morphology (nerve length, tortuosity, and reflectivity) returned to normal levels.

Current understanding of meningeal and cerebral vascular function underlying migraine headache.

BACKGROUND: The exact mechanisms underlying the onset of a migraine attack are not completely understood. It is, however, now well accepted that the onset of the excruciating throbbing headache of migraine is mediated by the activation and increased mechanosensitivity (i.e. sensitization) of trigeminal nociceptive afferents that innervate the cranial meninges and their related large blood vessels. OBJECTIVES: To provide a critical summary of current understanding of the role that the cranial meninges, their associated vasculature, and immune cells play in meningeal nociception and the ensuing migraine headache. METHODS: We discuss the anatomy of the cranial meninges, their associated vasculature, innervation and immune cell population. We then debate the meningeal neurogenic inflammation hypothesis of migraine and its putative contribution to migraine pain. Finally, we provide insights into potential sources of meningeal inflammation and nociception beyond neurogenic inflammation, and their potential contribution to migraine headache.

Endoscopic Corneal Neurotization: Technique and Initial Experience.

PURPOSE: The authors describe a minimally invasive surgical technique to re-establish corneal sensibility in a patient with neurotrophic keratopathy with the supraorbital nerve harvested endoscopically. METHODS: Pedicled contralateral supraorbital nerve was harvested endoscopically through small eyelid crease and scalp incisions and transferred to the affected eye. RESULTS: Endoscopic corneal neurotization was successfully performed with restoration of corneal sensibility and corneal epithelial integrity. CONCLUSIONS: The use of an endoscope allows for a minimally invasive approach to successful corneal neurotization with the supraorbital nerve.

Impact of herpetic stromal immune keratitis in corneal biomechanics and innervation.

PURPOSE: To study corneal innervation in eyes with history of herpetic keratitis and its correlation with corneal sensitivity and biomechanical properties. METHODS: A total of 56 eyes were included, of which 16 had a history of unilateral immune stromal herpetic keratitis, 16 were their contralateral eyes, and 20 were healthy controls. Structural analysis of corneal nerve plexus was performed by confocal microscopy. Biomechanical properties were measured with the Ocular Response Analyzer. Corneal sensitivity was assessed by contact (Cochet-Bonnet) and non-contact (Belmonte) esthesiometry. RESULTS: The eyes with a history of herpetic keratitis had reduced sensitivity for mechanical stimuli when compared to healthy eyes (1441.88 ± 83 ml/min vs. 67.9 ± 7.86 ml/min). Nerve fiber density in the corneas with a history of herpetic disease was lower (4.13 ± 2.19 U/image) than in the contralateral eyes (7.44 ± 2.9 U/image, p value = 0.01) and than in healthy controls (10.35 ± 2.01, p value < 0.0001). The best structural and functional correlation was established between the total length of nerves per section and mechanic threshold assessed by Belmonte esthesiometer (Coef. -0.58 p value < 0.0001) and between total length of nerves and corneal resistance factor (CRF) (Coef. -0.64, p value < 0.0001). CONCLUSIONS: The corneal sensitivity impairment in eyes with immune stromal herpetic keratitis can be explained by the loss of nerve fibers. Biomechanical corneal properties are affected as well. Corneal hysteresis (CH) and CRF are lower for the eyes with a history of herpetic keratitis, and also for the contralateral eye when compared to healthy controls.

Efficacy of 2-Month Treatment With Cord Blood Serum Eye Drops in Ocular Surface Disease: An In Vivo Confocal Microscopy Study.

PURPOSE: To investigate the morphological changes of corneal epithelium and subbasal nerves by in vivo confocal microscopy in patients with ocular surface disease (OSD) treated with cord blood serum (CBS) eye drops. METHODS: Twenty patients with OSD (mean age 61.1 ± 12.6 years) were included in this prospective 1-arm study and treated with CBS eye drops for 2 months. Corneal sensitivity, Schirmer test score, breakup time, subjective symptoms [Ocular Surface Disease Index (OSDI) and Visual Analogue Scale (VAS)], and corneal staining were evaluated before (T0) and after (T1) treatment. In vivo confocal microscopy analyzed giant epithelial cells, subbasal nerve number and tortuosity, neuromas, beading, and dendritic cells (DCs) in the central cornea. RESULTS: OSDI, Visual Analogue Scale, and Oxford grading values significantly decreased at T1 versus T0 (respectively, 44.1 ± 18.9 vs. 74.2 ± 13.9; 3.7 ± 1.5 vs. 8.9 ± 0.9; and 2.4 ± 1.1 vs. 3.3 ± 1.3; P < 0.0001), whereas corneal sensitivity, Schirmer test score, and breakup time significantly increased (respectively, 49.5 ± 2.6 vs. 47.9 ± 2.9; 3.2 ± 2.0 vs. 2.4 ± 2.2; 4.6 ± 3.1 vs. 3.8 ± 2.1; P < 0.0001). Corneal nerve morphology improved at T1 versus T0 with a higher total nerve number (3.4 ± 1.6 vs. 2.5 ± 1.6 per frame) and lower tortuosity (3.0 ± 0.7 vs. 3.5 ± 0.6) (P < 0.01). The number of patients presenting with giant epithelial cells, beading, and neuromas decreased at T1. DC density did not change after treatment. The detection of neuromas and higher DC density at T0 were associated with greater OSDI reduction at T1 (P < 0.001). CONCLUSIONS: CBS eye drops significantly improved corneal nerve morphology and subjective symptoms in patients with severe OSD. The presence of neuromas and higher dendritic cell density at baseline were associated with greater reduction of discomfort symptoms after treatment.

Effect of corneal cross-linking on contact lens tolerance in keratoconus.

BACKGROUND: The aim was to investigate changes in corneal sensation and rigid gas-permeable (RGP) contact lens tolerance after corneal cross-linking (CXL) on patients with keratoconus. METHODS: Thirty eyes of 30 patients, who were RGP lens intolerant, were treated with CXL. The main outcome measures were corneal sensation evaluation by Cochet-Bonnet esthesiometry, sub-basal nerve fibre assessment by corneal in vivo confocal microscopy and RGP contact lens tolerance evaluation with the Likert scale and wearing time. All eyes were evaluated preoperatively and post-operatively at one, three and six months after CXL procedure. RESULTS: The mean age was 25.3 ± 6.2 years. Preoperatively, the maximum keratometry (Kmax) in study eyes was 56.89 ± 4.60 D. Six months after CXL, it reduced to 56.03 ± 4.85 D (p = 0.01). Preoperative mean corneal sensation was 0.44 ± 0.05 g/mm2 , (range: 0.40 to 0.55); it was significantly decreased at the first month and increased to preoperative values after six months. The sub-basal nerve plexus could not be visualised in 90 per cent of the patients by confocal microscopy at one month post-operatively. Gradual restoration of corneal innervation with almost similar preoperative levels at post-operative month six was noted. There were significant differences in Likert scores between preoperative and third and sixth months after CXL. Likert scale scores correlated significantly with corneal sensitivity. CONCLUSION: It can be concluded that increased RGP contact lens tolerance after CXL may be associated with the potential role of decreased corneal sensitivity and corneal flattening after CXL.

Effect of Autologous Serum Eye Drops in Patients with Sjögren Syndrome-related Dry Eye: Clinical and In Vivo Confocal Microscopy Evaluation of the Ocular Surface.

AIM: To evaluate in vivo changes after therapy using autologous serum (AS) eye drops in Sjögren's syndrome (SS)-related dry eyes by confocal microscopy. PATIENTS AND METHODS: In this study, 24 patients with SS-related dry eyes [12 in AS eye drop therapy and 12 in artificial tear (AT) therapy] and 24 healthy volunteers were recruited. Ocular Surface Disease Index (OSDI), central corneal thickness, tear film, break-up time, corneal and conjunctival staining, Schirmer's test and corneal confocal microscopy were investigated. RESULTS: Tear production, tear stability, corneal staining, inflammation, and central corneal thickness, Langherans cells, activated keratocytes, intermediate epithelial cell density, nerve tortuosity, number of sub-basal nerve branches, and number of bead-like formations differed between patients and controls (p<0.0001). The AT and AS groups differed in the OSDI, number of branches, and number of beadings (p<0.0001). CONCLUSION: AS eye drops improve symptoms and confocal microscopy findings in SS-related dry eyes.

Pathogenesis of optic disc edema in raised intracranial pressure.

Optic disc edema in raised intracranial pressure was first described in 1853. Ever since, there has been a plethora of controversial hypotheses to explain its pathogenesis. I have explored the subject comprehensively by doing basic, experimental and clinical studies. My objective was to investigate the fundamentals of the subject, to test the validity of the previous theories, and finally, based on all these studies, to find a logical explanation for the pathogenesis. My studies included the following issues pertinent to the pathogenesis of optic disc edema in raised intracranial pressure: the anatomy and blood supply of the optic nerve, the roles of the sheath of the optic nerve, of the centripetal flow of fluids along the optic nerve, of compression of the central retinal vein, and of acute intracranial hypertension and its associated effects. I found that, contrary to some previous claims, an acute rise of intracranial pressure was not quickly followed by production of optic disc edema. Then, in rhesus monkeys, I produced experimentally chronic intracranial hypertension by slowly increasing in size space-occupying lesions, in different parts of the brain. Those produced raised cerebrospinal fluid pressure (CSFP) and optic disc edema, identical to those seen in patients with elevated CSFP. Having achieved that, I investigated various aspects of optic disc edema by ophthalmoscopy, stereoscopic color fundus photography and fluorescein fundus angiography, and light microscopic, electron microscopic, horseradish peroxidase and axoplasmic transport studies, and evaluated the effect of opening the sheath of the optic nerve on the optic disc edema. This latter study showed that opening the sheath resulted in resolution of optic disc edema on the side of the sheath fenestration, in spite of high intracranial CSFP, proving that a rise of CSFP in the sheath was the essential pre-requisite for the development of optic disc edema. I also investigated optic disc edema with raised CSFP in patients, by evaluating optic disc and fundus changes by stereoscopic fundus photography and fluorescein fundus angiography. Based on the combined information from all the studies discussed above, it is clear that the pathogenesis of optic disc edema in raised intracranial pressure is a mechanical phenomenon. It is primarily due to a rise of CSFP in the optic nerve sheath, which produces axoplasmic flow stasis in the optic nerve fibers in the surface nerve fiber layer and prelaminar region of the optic nerve head. Axoplasmic flow stasis then results in swelling of the nerve fibers, and consequently of the optic disc. Swelling of the nerve fibers and of the optic disc secondarily compresses the fine, low-pressure venules in that region, resulting in venous stasis and fluid leakage; that leads to the accumulation of extracellular fluid. Contrary to the previous theories, the various vascular changes seen in optic disc edema are secondary and not primary. Thus, optic disc edema in raised CSFP is due to a combination of swollen nerve fibers and the accumulation of extracellular fluid. My studies also provided information about the pathogeneses of visual disturbances in raised intracranial pressure.

Comparison of corneal sensation between small incision lenticule extraction (SMILE) and femtosecond laser-assisted LASIK for myopia.

PURPOSE: To compare the impact on corneal sensation after small incision lenticule extraction (SMILE) and femtosecond laser-assisted LASIK (femto-LASIK) in patients with myopia. METHODS: In this prospective, nonrandomized comparative study, 71 subjects were enrolled. Thirty-eight eyes of 38 patients underwent SMILE and 33 eyes of 33 patients underwent femto-LASIK. Corneal sensation was tested with Cochet-Bonnet esthesiometry in five corneal areas preoperatively and at 1 week and 1, 3, and 6 months postoperatively. Comparison of corneal sensation was performed for the SMILE and femto-LASIK groups. Additionally, the correlations were evaluated between the postoperative corneal sensation, preoperative spherical equivalent, and ablation depth. RESULTS: All tested areas within the cap or flap demonstrated corneal hypoesthesia immediately after both surgeries. SMILE-treated eyes showed less compromised corneal sensation than femto-LASIK-treated eyes at all postoperative visits in the central, inferior, nasal, and temporal areas at the 1-week and 1-month visits. In the SMILE group, the inferior, nasal, and temporal quadrants recovered faster than other areas. In the femto-LASIK group, the sensation over the flap did not recover to preoperative levels by postoperative 6 months. There was no correlation between postoperative corneal sensation, preoperative spherical equivalent, and ablation depth in both groups. CONCLUSIONS: The impairment of corneal sensation was less significant in the SMILE group than in the femto-LASIK group and was independent of preoperative spherical equivalent or ablation depth.

Corneal nerves in health and disease.

Corneal nerves are responsible for the sensations of touch, pain, and temperature and play an important role in the blink reflex, wound healing, and tear production and secretion. Corneal nerve dysfunction is a frequent feature of diseases that cause opacities and result in corneal blindness. Corneal opacities rank as the second most frequent cause of blindness. Technological advances in in vivo corneal nerve imaging, such as optical coherence tomography and confocal scanning, have generated new knowledge regarding the phenomenological events that occur during reinnervation of the cornea following disease, injury, or surgery. The recent availability of transgenic neurofluorescent murine models has stimulated the search for molecular modulators of corneal nerve regeneration. New evidence suggests that neuroregenerative and inflammatory pathways in the cornea are intertwined. Evidence-based treatment of neurotrophic corneal diseases includes using neuroregenerative (blood component-based and neurotrophic factors), neuroprotective, and ensconcing (bandage contact lens and amniotic membrane) strategies and avoiding anti-inflammatory therapies, such as cyclosporine and corticosteroids.

Corneal complications in streptozocin-induced type I diabetic rats.

PURPOSE. This study seeks to characterize corneal functions and complications in a streptozocin (STZ)-induced rat model of type I diabetes mellitus (DM) and to understand the pathogenesis of diabetic keratopathy. METHODS. DM was induced via STZ injection in Sprague-Dawley rats. Body weight, length, and corneal size were measured and compared with the age-matched normal controls. Corneal morphology and histology were evaluated with slit lamp, digital confocal microscopy and hematoxylin and eosin staining. Tear secretion was measured with cotton threads, and corneal sensitivity was determined with an esthesiometer. Protein expression and distribution were assessed with Western blotting and immunohistochemistry. Wound healing was determined using an in vivo corneal epithelial debridement model. RESULTS. Compared with the normal control rats, STZ rats had reduced body weight, and body length, but minimally affected corneal size. No significant changes in ocular surface regularity, corneal thickness, and morphology were noted in diabetic corneas. STZ rats showed stronger Rose Bengal staining, decreased tear secretion, slightly attenuated sensitivity, less innervation, delayed epithelial wound healing, and impaired epidermal growth factor receptor signaling in their corneas. While the expression of adherens junction protein ß-catenin, and tight junction proteins occludin and ZO-1 was unchanged, the formation of these junctions after wound closure was delayed. CONCLUSIONS. Pathogenesis of diabetic keratopathy involves multiple tissues and/or cell types and several events including reduced tear secretion, impaired innervation, weakened cell junction, and altered wound responses. These insights may prove useful for the clinical translation of evolving strategies for the management and treatment of diabetic corneal complications.

Corrugator supercilii transection for headache emanating from the frontal region: a clinical evaluation of ten patients.

Chronic daily headache (CDH) located in the frontal region is a common problem. We have previously described the positive results that were achieved with botulinum toxin (BTX) injections in the musculus corrugator supercilii (MCS) for this disorder. Nowadays, we offer transection of this muscle to patients following a minimum of two BTX injections, provided these injections result in a significant reduction of pain. This procedure is based on the assumption that the pathophysiological mechanism in some of these patients suffering from CDH is a neural entrapment of the supratrochlear nerve in the corrugator muscle. To assess the effect of transection, we have evaluated all the consecutive patients (n = 10) so far. Treatment was successful in nine of these patients. Prior to the treatment, the mean pain score in the 9 successfully treated patients was 8.1 (range 6-9), after transection this had been reduced to 0.8 (range 0-3). All of these successfully treated patients ceased their daily use of pain relief medication for their frontally localised headaches. Moreover, they stated that they would definitely undergo surgery, if they were to find themselves in the same situation again. Therefore, we conclude that transection of the MCS is an efficient and successful procedure for a carefully selected group of patients suffering from CDH in the frontal region. Most of all we intend to popularise this pathophysiological concept based on the distinct possibility that some headaches might be due to neural entrapment.

LASIK-associated dry eye and neurotrophic epitheliopathy: pathophysiology and strategies for prevention and treatment.

PURPOSE: To review the pathophysiology of LASIK-associated dry eye conditions and provide insights into prophylaxis to decrease the incidence of dry eye after LASIK and to treat the condition when it occurs. METHODS: A review of the literature was performed on LASIK-associated dry eye and the experience of the authors was summarized. RESULTS: LASIK has a neurotrophic effect on the cornea, along with other changes in corneal shape, that affect tear dynamics causing ocular surface desiccation. Dry eye is one of the most common complications of LASIK surgery. Symptoms of dryness may occur in more than 50% of patients, with other complications such as fluctuating vision, decreased best spectacle-corrected visiual acuity, and severe discomfort occurring in approximately 10% of patients. Preoperative dry eye condition is a major risk factor for more severe dry eye after surgery and should be identified prior to surgery. Optimization with artificial tears, nutrition supplementation, punctal occlusion, and topical cyclosporine A in patients with symptoms or signs of dry eye prior to LASIK decreases the incidence of more bothersome symptoms following surgery. Patients with LASIK-induced neurotrophic epitheliopathy often respond to topical cyclosporine A treatment, which treats the underlying inflammation and may benefit nerve regeneration. CONCLUSIONS: LASIK-induced dry eye and neurotrophic epitheliopathy are common complications of LASIK surgery. Optimization of the ocular surface prior to surgery decreases the incidence and severity of postoperative symptoms of the condition.

Papillary endothelial hyperplasia of the orbit: report of a case highlighting a pitfall on fine needle aspiration biopsy.

BACKGROUND: Papillary endothelial hyperplasia (PEH) is an unusual form of thrombus organization that occurs predominantly in the extremities, including the head and neck. However, it is rare in the orbit/ocular region. Although the histologic features of PEH have been well described, the cytologic diagnosis remains difficult. CASE: A 63-year-old man presented with a left intraorbital mass that was increasing in size and associated with paresthesia and a recent history of excision of squamous cell carcinomas (SCC) from his left cheek. Fine needle aspiration biopsy (FNAB) yielded very limited material, predominantly blood. However, 1 Papanicolaou-stained slide showed groups of atypical cells with scanty but dense cytoplasm and large, hyperchromatic nuclei with prominent nucleoli. SCC was favored, and excision was performed. Histology showed PEH within an assumed cystic lymphangioma, associated with inflammatory and fibrotic change in the compressed supraorbital nerve. CONCLUSION: To our knowledge this is the third report on the cytology of PEH and the first report of FNAB in PEH of the orbit. The case was also unusual as it was the second metachronous PEH in the patient.

[Post-traumatic supraorbital neuralgia: a benign condition]. / Neuralgia supraorbitaria postraumática: una entidad benigna.

INTRODUCTION: Supraorbital neuralgia has only recently been described. Most of the cases reported involve patients suffering from chronic idiopathic neuralgias that are difficult to treat and sometimes require surgery to release the nerve. We present our experience in patients with a variant of this neuralgia which has a known causation, is commonly seen and has a benign prognosis. CASE REPORTS: We studied five patients, four females and one male, with a mean age of 55 years (range: 29-69 years). They had all suffered direct banal traumatic injury to the frontal region due to different causes. Four of them developed continuous, piercing or burning-type pain; three of them had paroxysmal pain and one had itching. There were no autonomic manifestations. All of them were found to be abnormally sensitive in the affected area, with tactile hypaesthesia, hyperalgesia or allodynia and a positive Tinel's sign. Neuroimaging tests were normal. Two patients were treated with gabapentin and amitriptyline. One was treated with an anaesthetic blockade, which afforded temporary relief. Three of them received no treatment at all. After one year of follow-up, all of them had improved and three were no longer in pain, although sensory alterations persisted in all cases. CONCLUSIONS: Post-traumatic supraorbital neuralgia is a frequent condition, although it is probably underdiagnosed. It has its own characteristic clinical and developmental features that distinguish it from idiopathic supraorbital neuralgia. Progress is usually good and it responds favourably to symptomatic treatment, if needed.

Hemicrania with massive autonomic manifestations and circumscribed eyelid erythema.

OBJECTIVES: To describe a unilateral headache that in addition to the typical shortlasting unilateral neuralgiform headache attacks with conjunctival injection, tearing, sweating and rhinorrhea (SUNCT) syndrome - traits with excessive and ipsilateral autonomic phenomena - had circumscribed eyelid erythema and adjacent ocular redness. OBSERVATIONS: A 60-year-old female had excessive, right-sided lacrimation and local pain at 15 years of age. Due to steadily increasing discomfort, with lacrimation and swelling over the outer part of the upper eyelid, the right lacrimal gland was removed at 20 years of age, with a suspicion of lacrimal gland adenoma. Preoperatively, symptomatic side mild-degree eyelid erythema/rhinorrhea were integral parts of the attack. After years with minor complaints, she, in the mid-twenties, experienced more long-lasting pain attacks, and pain soon became the main problem. A marked, distinct erythema on the lateral part of the right-sided eyelids and marked, localized 'eye redness' in the adjacent area were main ingredients of the attacks together with eyelid edema and viscous rhinorrhea. There were visible vessels below the eye, and telangiectasia of the upper eyelid. CONCLUSIONS: This headache has many similarities with SUNCT - but has several, grossly deviating traits: the temporal aspects, excruciatingly intense pain attacks, and above all marked, lateral eye-lid erythema, and adjacent, massive ocular reddening. This constellation probably alienates it from SUNCT.

Diagnostic accuracy of trigeminal reflex testing in trigeminal neuralgia.

The authors prospectively studied 120 consecutive patients with trigeminal neuralgia (TN) to identify the clinical and laboratory features that most accurately distinguished symptomatic from classic TN. After a standardized evaluation, they identified 24 patients with symptomatic TN. Age, sensory examination, and affected division were not useful in the differential diagnosis. In contrast, electrophysiologic testing of trigeminal reflexes accurately distinguished symptomatic from classic TN (sensitivity 96%, specificity 93%).

Change to corneal morphology after refractive surgery (myopic laser in situ keratomileusis) as viewed with a confocal microscope.

PURPOSE: This study aimed to look at morphological changes induced by myopic laser in situ keratomileusis (LASIK) in the human cornea using the confocal microscope and to investigate the link between these changes and alterations to corneal sensitivity. METHODS: An in vivo slit-scanning real-time confocal microscope (Tomey ConfoScan P4, Erlangen, Germany) fitted with an Achroplan 40x/0.75 NA immersion objective and a Cochet-Bonnet esthesiometer were used to examine the morphology and sensitivity of the central corneas of six subjects (12 eyes) at an initial visit (before surgery), and at 1 week, 1 month, 3 months, and 6 months after LASIK for myopia. RESULTS: Keratocyte density anterior to the flap interface showed differences between visits (p < 0.0001) and was found to be lower than at the initial visit at 1 week, 1 month, 3 months, and 6 months. Microfolds were noted at the level of the anterior limiting membrane in 11 of 12 eyes after surgery at all visits. Highly reflective flap interface particles were seen in all eyes at all visits after surgery. The subepithelial nerve fiber layer was clearly visible before surgery but could not be imaged in any of the eyes after surgery. Short, unconnected nerve fibers were observed 3 months after surgery; these appeared to form anastomosing interconnections after 6 months. Postsurgical corneal sensitivity was reduced during the first 3 months and recovered to presurgical levels after 6 months. CONCLUSION: LASIK showed a decrease in anterior keratocyte density and microfolds in the anterior limiting membrane, and reflective particles were observed at the flap interface. Corneal sensitivity was depressed during the first 6 months after LASIK surgery; this time course paralleled the appearance of nerve regeneration during this period. Confocal microscopy is capable of providing interesting new insights into the effects of refractive surgery on corneal morphology.