Terrien's Marginal Degeneration Research Articles

Tenon patch graft repair in an unusual case of leaking wound after phacoemulsification

Leaking corneal incisions after phacoemulsification can be associated with devastating consequences and can lead to secondary complications including endophthalmitis, choroidal hemorrhage, and glaucoma. We report a case of leaking corneal wound after routine phacoemulsification at the site of corneal thinning associated with terrien marginal degeneration (TMD), which was missed preoperatively, consequently leading to this surgical complication. TMD is a rare form of ectatic corneal condition with a very slow progression. The main aim of treatment is to improve the vision and corneal integrity, owing to its uncertain etiology. Surgical intervention in TMD, however, has been advocated when perforation is imminent, but the chance of spontaneous and intraoperative perforation increases in cases with severe thinning of corneas resulting in poor visual outcomes as compared to non-perforated eyes. In our case, as an amniotic membrane or corneal tissue was not available at the time of presentation, we proceeded with a Tenon patch graft with the application of cyanoacrylate glue, following which a bandage contact lens was applied. This case highlights the importance of a meticulous preoperative workup of the patient to identify any abnormality of the cornea, especially at the incision sites, to avoid such complications during the surgery.

Une ectasie cornéenne sévère unilatérale de l’enfant

We report a case of unilateral Terrien's marginal degeneration in a 14-year-old girl. Slit-lamp examination of the affected eye revealed 360° circumferential lipid deposits with 6mm of superior limbal distension, superficial neovascularization, a zone of corneal thinning from 3:00 to 9:00 with a zone of corneomalacia at 11:00. The remainder of the cornea was clear, without fluorescein staining or anterior chamber reaction. Terrien's marginal degeneration (TMD) is typically known to occur bilaterally in men over the age of 40. Terrien's degeneration must be differentiated from other causes of peripheral corneal thinning; the primary differential diagnosis is Fuchs' marginal keratitis. Other causes of corneal thinning must be ruled out, including Mooren's ulcer. In Terrien's degeneration, there is no central mined edge in the thinning sulcus, the epithelium remains intact, and affected patients do not present with pain. Other differential diagnoses include pellucid marginal degeneration and sulcus degeneration, which are characterized by the absence of lipid infiltrates associated with the central region of the thinning zone, thus distinguishing them from TMD. It is important to keep in mind that Terrien's marginal degeneration can occur in children.

Does Corneal Topography Using 3-Dimensional Optical Coherence Tomography Suggest Different Subtypes of Terrien Marginal Degeneration?

The aim of this study was to analyze corneal topography relative to astigmatism, higher order aberrations, and corneal curvatures in Terrien marginal degeneration using 3-dimensional anterior-segment optical coherence tomography. Twenty-nine eyes of 15 Finnish patients from a tertiary referral center had topographic axial power maps classified into 4 patterns by visual grading: crab claw (CC), mixed (M), arcuate (A), and normal. Regular astigmatism, keratometry, higher order aberrations, maximal corneal thinning, apex thickness, and curvature changes relative to best fit sphere toward maximal peripheral thinning were compared. Four, 9, and 12 eyes were classified as CC, M, and A, respectively; 1 as normal with clinical disease; and 3 as normal with unilateral disease. Median follow-up was 2.3 (range, 0-7.2) years. Three eyes changed pattern. Patients with the CC pattern were the youngest when diagnosed, progressed more rapidly, exhibited cavities in superior quadrants with anterior bulging, and had greater higher order posterior aberrations. Patients with the M pattern were older, progressed slower, and showed superonasal asymmetric corneal steepening extending centrally, often with asymmetric bow tie. Patients with pattern A showed little progression and were the oldest when diagnosed, with maximal corneal thinning equally in all quadrants. According to the Wang classification, the median stage was 4, 2, and 2 in CC, M, and A patterns, respectively, whereas it was always 2 by the Süveges classification. Terrien marginal degeneration is characterized by distinct corneal topographic patterns that differ in tomographic features, suggesting existence of subtypes in addition to different stages of disease. Patients representing CC and M patterns might benefit from more frequent monitoring.

Prosthetic Replacement of the Ocular Surface Ecosystem for Terrien Marginal Degeneration: A Case Series.

To assess outcomes of the Prosthetic Replacement of the Ocular Surface Ecosystem (PROSE) treatment in patients with advanced Terrien marginal degeneration (TMD). This is a retrospective case series of patients with advanced TMD who were assessed and fit with customized PROSE lenses. Data were collected on PROSE fitting details including visual acuity (VA) before and after PROSE, slit-lamp findings, and corneal tomography scans. Six eyes in four patients were included. All patients attempted at least one other contact lens (CL) modality before PROSE. Some patients had corneal comorbidities such as pseudopterygium and pseudobleb that contributed to intolerance to previous lenses and warranted extra considerations in the fitting process. With PROSE, VA improved in all six eyes. Patients with structural corneal comorbidities achieved improved vision, comfort, and lens tolerance with PROSE. Two eyes had noncorneal ocular comorbidities that limited PROSE efficacy. Another eye discontinued PROSE wear because of limbal stem-cell disease progression necessitating a limbal stem-cell transplant. PROSE treatment can be an effective option to improve vision and comfort for patients with advanced TMD who are intolerant to first-line therapeutic CL modalities, even in the presence of other corneal comorbidities.

Peripheral Ulcerative Keratitis: A Review.

Peripheral ulcerative keratitis (PUK) is a rare but serious ocular condition that is an important clinical entity due to its ophthalmological and systemic implications. It is characterized by progressive peripheral corneal stromal thinning with an associated epithelial defect and can be associated with an underlying local or systemic pro-inflammatory condition, or present in an idiopathic form (Mooren ulcer). Associated conditions include autoimmune diseases, systemic and ocular infections, dermatologic diseases, and ocular surgery. Cell-mediated and auto-antibody-mediated immune responses have been implicated in the pathogenesis of PUK, destroying peripheral corneal tissue via matrix metalloproteinases. Clinically, patients with PUK present with painful vision loss, a peripheral corneal ulcer, and often adjacent scleritis, episcleritis, iritis, or conjunctivitis. Diagnostic evaluation should be focused on identifying the underlying etiology and ruling out conditions that may mimic PUK, including marginal keratitis and Terrien marginal degeneration. Treatment should be focused on reducing local disease burden with topical lubrication, while simultaneously addressing the underlying cause with antimicrobials or anti-inflammatory when appropriate. Existing and emerging biologic immunomodulatory therapies have proven useful in PUK due to autoimmune conditions. Surgical treatment is generally reserved for cases of severe thinning or corneal perforation.

Femtosecond laser-assisted corneoscleral lamellar keratoplasty for peripheral corneal disease

Objective: To evaluate the effect of femtosecond laser-assisted corneoscleral lamellar keratoplasty (FL-CSLK) on peripheral corneal disease (PCD). Methods: Retrospective cohort study. Six patients (6 eyes) with PCD who underwent FL-CSLK in Qingdao Eye Hospital from March 2014 to March 2017 were grouped as the FL-CSLK group, including 4 males and 2 females, aged (46.7±17.9) years. In addition, 8 patients (8 eyes) with PCD who underwent traditional corneoscleral lamellar keratoplasty in the same period were included in the control group. The items for analyses were as follows: visual function recovery, including visual acuity, equivalent spherical power, and astigmatism; the state of the cornea, including the healing time of the corneal epithelium, the transparency of the graft, the thickness of the corneal graft and implant bed, and the loss rate of corneal endothelial cells; intraoperative and postoperative complications, including high intraocular pressure, interlayer effusion, delayed corneal epithelial healing, immune rejection, and primary recurrence. Paired t-test was used to compare the best corrected visual acuity (BCVA), equivalent spherical power, and astigmatism before and after operation. The BCVA and corneal graft epithelial healing time between the two groups were compared by independent sample t-test. Results: The 6 patients in the FL-CSLK group included 2 cases of Mooren ulcer, 3 cases of Terrien marginal degeneration, and 1 case of pellucid marginal degeneration. The control group consisted of 4 eyes with Mooren ulcer and 4 eyes with Terrien marginal degeneration. The BCVA (logarithm of the minimum angle of resolution) in the FL-CSLK group was 0.35±0.09 at 6 months after operation, which was significantly higher than that before operation (1.17±0.15; t=9.01, P<0.001) and at 6 months after operation in the control group (0.78±0.29; t=-3.96, P=0.003). The equivalent spherical power was (4.8±2.7) D, lower than that before operation (t=-3.71, P=0.014), and the astigmatism power was (10.1±4.1) D, lower than that before operation (t=6.04, P=0.002) in the FL-CSLK group. The healing time of the graft epithelium in the FL-CSLK group and control group was (8.5±3.3) days and (12.8±6.1) days, respectively, with no significant difference (t=-1.54, P=0.149). The central thickness of the graft in the FL-CSLK group was (525±47) μm at 6 months after operation, the central thickness of the implant bed was (189±119) μm, and the loss rate of the corneal endothelium was 7.5%±2.1%. In the control group, 1 case had intraoperative perforation, 2 cases had intracorneal hemorrhage, and 1 case had intracorneal epithelial implantation cysts and graft ulcer. There were no intraoperative and postoperative complications in the FL-CSLK group. Conclusions: FL-CSLK can yield good clinical results in the treatment of PCD. The smooth optical interface made by femtosecond lasers can help the patient achieve a good visual prognosis. The procedure reduces the risk of corneal perforation and thus improves the surgery safety.

Clinical profile and demographic distribution of Terrien's marginal degeneration in a multitier ophthalmology network in India.

Purpose:To describe the clinical profile and demographic distribution of Terrien’s marginal degeneration (TMD) in patients presenting to a multitier ophthalmology hospital network in India.Methods:This cross-sectional hospital-based study included 2,470,793 new patients presenting between September 2012 and September 2020 (~8 years period). Patients with a clinical diagnosis of TMD in at least one eye were included as cases. The data were collected using an electronic medical record system.Results:Overall, 184 (0.007%) new patients were diagnosed. Over half of patients were males (56.52%) with bilateral affliction (54.89%). The mean age of the patients was 38.63 ± 16.75 years. Majority (28.26%) of the patients were between 21 and 30 years of age bracket. The number of patients were from rural and urban districts were comparable (41.85% vs. 48.37%). The most common clinical signs were ectasia/thinning (50.53%), corneal scar (44.21%), and prominent nerves (5.26%). Associated ocular comorbidities included vernal keratoconjunctivitis in 6 (2.11%) eyes, meibomitis in 6 (9.7%) eyes, squamous blepharitis in 2 (3.2%) eyes, dry eye in 2 (3.2%) eyes, cataract in 46 (74.2%) eyes, and glaucoma in 6 (9.7%) eyes. Most of the eyes had mild or no visual impairment (43.86%). Two (0.7%) eyes had spontaneous perforation patients. None of patients had hydrops in the years of follow-up. Keratoplasty was performed in 3.86%.Conclusion:TMD is a rare disease affecting patients seeking eye care at the ophthalmology network. It commonly affects adult males and is predominantly bilateral. The disease progression is slow, and risk of spontaneous perforation was low. At initial presentation, visual impairment was mild to moderate in majority and the most common surgical intervention was cataract surgery during the study period.

Anterior Segment Ischemia After Peripheral Annular Lamellar Sclerokeratoplasty for Advanced Terrien Marginal Degeneration.

A man with 360° bilateral peripheral thinning, peripheral vascularization, and lipid deposition diagnosed with Terrien marginal degeneration, underwent a 360° peripheral annular lamellar sclerokeratoplasty (PALK) (tuck-in) in the right eye for 90% peripheral thinning and high astigmatism. One-week postoperatively, a sudden drop in vision to counting fingers 1 m from 20/50 with circumciliary congestion, diffuse corneal edema, intense anterior chamber inflammation, keratic precipitates with fixed dilated pupil, and hypotony led to a diagnosis of suspected anterior segment ischemia. Anterior segment fluorescein angiography was suggestive of ischemia. After intensive topical and systemic steroids tapered over 6 months, his symptoms and signs improved. At the last follow-up 4 years later, his best contact lens-corrected visual acuity was 20/30. Anterior segment ischemia has not been reported after a PALK for advanced corneal ectatic disorders. Prompt diagnosis and commencement of intensive steroids was helpful in reversing this condition.

Ultra‐high frequency 70 Mhz ultrasound and IVCM are useful for diagnostic and therapeutic management of atypical Terrien's marginal degeneration

AbstractPurposeTerrien's marginal degeneration is a rare corneal disease usually characterized by an «insidious thinning of the cornea near the limbus» (Pouliquen Y et al. 1989). Its diagnosis remains essentially clinical.AimTo present the help of innovating imaging in an atypical cystic presentation of Terrien's marginal degeneration.MethodsAn 87‐year‐old caucasian patient presented since several month a voluminous cystic lesion of the limbus, bulky, neo‐vascularized, in the inferior part of the eye, that compromised the palpebral closure. No traumatic or surgical history was found. Slit‐lamp examination of the contralateral eye also revealed a degenerative area with corneal thinning. In order to determine the etiology of this lesion, 70 Mhz ultrasound (VevoMD high‐frequency ultrasound system, Fujifilm, Toronto, Canada), anterior segment optical coherence tomography (OCT, Casia 1, Tokyo, Japan) and in vivo confocal microscopy (IVMC, Vivascope 3000, LUCID, NY, USA) were performed. Surgical removal of the lesion consisted of en bloc removal of the cystic lesion followed by limbal conjunctiva and amniotic membrane graft for analgesic purposes and to accelerate wound healing. Histology and direct immunofluorescence were performed.Results70 Mhz ultrasonography and OCT revealed a single non‐segmented cyst, without scleral fistula or corneal thinning. IVMC showed a single well delineated cyst with clearly visible distinct partitions with no image in favour of malignancy. No signs of malignancy or ocular pemphigoid were founded by histology. We, therefore, concluded to an atypical presentation of Terrien's marginal degeneration.ConclusionsThe combination of sophisticated imaging like ultra‐high frequency 70 Mhz ultrasound, AS‐OCT and IVCM are necessary for diagnostic and therapeutic management of atypical cornea lesions.

Commentary: Clinical profile and demographic distribution of Terrien's marginal degeneration in a multitier ophthalmology network in India.

Commentary: Clinical profile and demographic distribution of Terrien's marginal degeneration in a multitier ophthalmology network in India.

One Disease, but Different Names: Fuchs’ Superficial Marginal Keratitis and Terrien Marginal Degeneration

Terrien marginal degeneration and Fuchs’ superficial marginal keratitis are considered rare and slowly progressive corneal diseases with a bilateral lesion, unknown etiology, and have a number of similar clinical signs. Clinically, Terrien marginal degeneration is characterized by peripheral thinning, which appears at the beginning of the disease usually in the upper half, but can also begin with the lower half of the cornea. In the case of Fuchs’ superficial marginal keratitis, biomicroscopic examination, at the initial stages of the disease’s development, in the lower and lower nasal segments, reveals peripheral corneal thinning. As a rule, in both diseases, the lesions on the two eyes are asymmetric, but peripheral corneal thinning is the main pathological sign. Purpose. To determine the diagnostic criteria for Terrien disease and Fuchs’ marginal keratitis, to identify their similarities and differences. Patients and methods. For the period 2017–2020, 40 patients were examined; they were divided into 3 groups. 30 patients with Terrien marginal degeneration, 7 patients with Fuchs’ superficial marginal keratitis, 3 patients with signs of Terrien marginal degeneration in one eye and typical manifestations of Fuchs’ superficial marginal keratitis in the other eye. The following methods were used for diagnostics: confocal microscopy, optical coherence tomography of the anterior segment, keratotopography. Results. A survey of 40 patients revealed many common clinical signs of two previously considered separate diseases. According to the literature, it is known that the main difference between these two diseases is the localization of corneal lesions. We found that different localization of the lesion in Terrien degeneration and superficial marginal Fuchs keratitis is present in some patients and only in the initial stages of both diseases. Conclusions . Terrien’s degeneration and Fuchs’ superficial marginal keratitis may be different variants of clinical manifestations or different stages of progression of the same disease. Since the etiology of Terrien’s degeneration and Fuchs’ superficial marginal keratitis had not been established, it is recommended to follow the clinical course of the diseases during treatment.

Diagnostic Criteria for Terrien Marginal Degeneration: Nordic Terrien Degeneration Study.

To refine the diagnostic criteria for Terrien marginal degeneration (TMD) based on experience in 3 Nordic countries. This is a retrospective, multicenter, hospital-based cross-sectional study of 49 eyes of 29 white patients in tertiary referral centers in Finland, Sweden, and Denmark from 1998 to January 2018. The median follow-up was 3 years. Symptoms, best corrected visual acuity, astigmatism, corneal thickness, curvature and cavities, stage, and progression were analyzed. TMD was diagnosed equally likely between 15 and 86 years of age (median, 47 years). Twenty patients (69%) had bilateral disease, and 62% were men. Seventeen patients (59%) had symptoms including blurred vision and ocular surface disease symptoms without inflammatory signs. Eight patients (28%) had slightly reduced corneal sensitivity. Median best corrected visual acuity was 20/25 (range, 20/16-20/200) and astigmatism was 2.6 diopters (D) (range, 0-10) with a mean progression of 0.41 D per year (range, 0-5.4). Age and astigmatism were not correlated. All eyes had peripheral vascularization, lipid deposits, and hyperreflectivity throughout thinned peripheral stroma and its anterior edge. The thinning progressed in 15 patients (52%). Of 26 patients, 8 (31%) had single or confluent paralimbal intrastromal cavities, most commonly superiorly. By Süveges classification, the stage was 2 (92%) or 3 (8%). Minimum corneal thickness and corneal curvature were loosely associated, leading to different stages in Wang classification in 34 eyes (69%). TMD is defined by peripheral corneal thinning, superficial neovascularization, lipid deposition at the leading edge, absence of ulceration and inflammation, and frequently cavitation. The most sensitive way to follow its progression is anterior segment optical coherence tomography.

Techniques of noncircular corneal transplantation

The management of peripheral corneal diseases, including Mooren's ulcer, Terrien's marginal degeneration, peripheral ulcerative keratitis and pellucid marginal degeneration is challenging. Circular grafts must either be very large, resulting in the excision of healthy tissue, or eccentric, leading to high levels of astigmatism. This review summarizes the range of noncircular keratoplasty procedures available to surgeons, in addition to their indications, and surgical techniques. Noncircular grafts have been demonstrated to be useful in the management of peripheral corneal diseases. They are effective at providing tectonic support and also facilitate visual rehabilitation. Specifically, they produce favourable postoperative visual and astigmatic outcomes. The evidence relating to these procedures is largely limited to case reports and case series, with no large-scale studies available. Noncircular keratoplasty procedures are useful in the management of peripheral corneal diseases, which is typically difficult. There is a need for larger studies to investigate the relative advantages and disadvantages of these procedures and further characterize their outcomes.

Idiopathic spontaneous filtering bleb: Is there an autoimmune etiology?

A 45-year-old male presented with complaints of defective vision for near. There was no prior history of trauma, recurrent redness, or surgery. He is a known patient of hypothyroidism and vitiligo. His best-corrected visual acuity was 6/6, N6 in both the eyes (BE). Slit-lamp examination revealed a diffuse, elevated, avascular thin bleb near the limbus in the superonasal quadrant with underlying scleral thinning in BE. Right eye (RE) showed clear cornea, quiet and deep anterior chamber, normal iris pattern, and clear lens. Left eye (LE) showed peripheral corneal vascularisation with lipid deposits at 10'o clock anterior to the area of scleral thinning and bleb formation, the rest of the anterior segment was normal [Fig. 1a and b]. Schirmer's test was normal and Seidel's test did not reveal any leak in BE. His intraocular pressure was 9 and 10 mm Hg in the RE and LE, respectively. Gonioscopy revealed open angles in BE with an area of hyperpigmentation around fistula at 2 o'clock in the RE and increased pigmentation with prominent iris processes in the nasal quadrant in LE [Fig. 1c and d]. The fundus examination revealed an average size disc with a cup to disc ratio of 0.4:1, healthy neuroretinal rim and attached retina in BE.Figure 1: Right eye showing superonasal diffuse avascular thin bleb (a). Left eye showing superonasal diffuse avascular thin bleb with scleral thinning, corneal vascularisation, and lipid deposits (b). Gonioscopy showing fistula with hyperpigmentation anterior to schwalbe's line at 2'0 clock (arrowhead) in the right eye (c) and increased pigmentation with prominent iris processes in the nasal quadrant in left eye (d). Ultrasound biomicroscopy image of the right (e) and left (f) eye showing communicating fistula between the anterior chamber and subconjunctival space, indicated by the arrowheadsCorneal topography was suggestive of oblique astigmatism with flattening along the meridian of the bleb without evidence of corneal ectasia in BE. Ultrasound biomicroscopy revealed a communicating fistula between the anterior chamber and subconjunctival space in BE [Fig. 1e and f]. Physical examination was unremarkable, except for depigmented patches in the skin. Blood investigations revealed high thyroid peroxidase antibody titer (157 IU/mL), whereas C-reactive protein, rheumatoid factor, and antinuclear antibody were within normal limits. Discussion Spontaneous filtering bleb is a rare condition, which can develop if a communicating fistula between the anterior chamber and subconjunctival space is established. Spontaneous filtering bleb has been reported in patients with Axenfeld syndrome,[1] Terrien marginal degeneration,[2] Traboulsi syndrome,[34] connective tissue diseases,[56] and without any ocular or systemic association.[27] Our patient with hypothyroidism and vitiligo, has scleral thinning and subconjunctival bleb in both the eyes. There were no signs of anterior segment abnormalities or facial dysmorphism. Considering the fact that our patient has 2 autoimmune systemic conditions, we postulate that the scleral thinning and spontaneous bleb formation could be due to autoimmune etiology. 2.1 Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. 2.2 Financial support and sponsorship Nil. 2.3 Conflicts of interest There are no conflicts of interest.

Updates on management of pellucid marginal degeneration: Topographic patterns, differential diagnosis, and surgical options

Pellucid marginal degeneration (PMD) is a rare ectatic corneal disease involving the inferior part of the cornea. It is difficult to differentiate between keratoconus (KCN) and PMD by slit lamp, especially in the detection of early and subclinical stages of the diseases. Corneal topography is the main diagnostic tool of PMD with characteristic diagnostic patterns “crab-claw” or “butterfly.” PMD could be mistaken as KCN, keratoglobus, and other peripheral thinning conditions such as Terrien marginal degeneration and Mooren's ulcer. Spectacles, soft and rigid gas permeable contact lens are the main visual correcting method in early stage of the disease. Different surgical techniques are available for PMD management; however, none of them were found to be effective, so further studies will be needed in the future.

Therapeutic Effects of Lamellar Keratoplasty on Terrien Marginal Degeneration.

To evaluate the therapeutic effects of lamellar keratoplasty (LK) on Terrien marginal degeneration (TMD). Retrospective interventional case series. Medical records of 63 patients (71 eyes) who received LK for TMD at Qingdao Eye Hospital, Shandong Eye Institute from December 1995 to March 2014 were reviewed. A total of 56 eyes were treated with partial LK and 15 eyes with total LK. Complications, visual acuity recovery, and graft status were evaluated. Mean age of the patients was 50.4 ± 16.8 years. The follow-up period was 2.5 ± 0.9 years. The uncorrected distance visual acuity (UDVA) increased from preoperative 0.90 ± 0.44 logarithm of the minimum angle of resolution (logMAR) to 0.53 ± 0.27 logMAR at 1 year after surgery (t = 16.256, P < 0.001). The corrected distance visual acuity (CDVA) was 0.69 ± 0.30 logMAR preoperatively, and increased to postoperative 0.38 ± 0.22 logMAR (t = -19.982, P < 0.001). After surgery, mean astigmatism was 5.33 ± 2.44 diopters (D) compared with preoperative 10.19 ± 4.32 D (t = 7.351, P < 0.001), and the spherical equivalent decreased from preoperative -2.23 ± 2.34 D to -0.75 ± 2.04 D (t = -2.677, P = 0.012). There was a significant difference in UDVA, ΔUDVA, CDVA, ΔCDVA, and refractive astigmatism between the partial LK and total LK groups. The most common intraoperative complication was corneal perforation. The postoperative complications included double anterior chamber, persistent graft epithelium defects, corneal vascularization, immune rejection, graft ulcers, cataract, and recurrence of marginal degeneration. LK can effectively reduce refractive errors, improve visual acuity, and reduce the risk of corneal perforation for patients with TMD. The visual acuity after partial LK is superior to that after total LK.

Crosslinking in infectious corneal ulcers and Terrien marginal degeneration

SummaryCorneal collagen crosslinking (CXL) is an established safe and effective option in the treatment of early keratoconus. This presentation reviews the published evidence and personal experience with CXL in special indications.The intrinsic toxicity of the oxidative CXL process, normally causing a temporarily acellular corneal stroma to a certain depth, implies an antiseptic potential on bacteria, fungi and amebae. This has been applied to refractory corneal infections with varying success. While most available evidence is anecdotal, some prospective studies appear to confirm the usefulness of CXL as an antimicrobial treatment.CXL in keratoconus is usually applied to the central cornea and aims at preventing the progression of ectasia, with minor effect on curvature and refraction. However, our experience with CXL in cases of peripheral ectatic conditions such as Terrien's disease shows that, beyond stabilization of the process, a marked improvement in astigmatism is possible with a persistent effect after a long term follow up. The possible implications on the mechanism of action of CXL and the pathogenesis of ectasia will be discussed.

High-Resolution Optical Coherence Tomography in the Differentiation of Inflammatory Versus Noninflammatory Peripheral Corneal Thinning.

To evaluate whether high-resolution optical coherence tomography (HR-OCT) can aid in differentiation of inflammatory versus noninflammatory causes of peripheral corneal thinning. Retrospective chart review of 10 patients with peripheral corneal thinning and their respective slit-lamp photographs and HR-OCT images. Ten patients were identified who had peripheral corneal thinning and HR-OCT images. Five had a clinical history consistent with Terrien marginal degeneration (TMD), whereas 5 had thinning believed to be inflammatory in origin. In the eyes with presumed TMD, patients denied pain or inflammation. HR-OCT images demonstrated stromal thinning in the presence of an intact epithelium. The stroma underneath the epithelium in the area of thinning had a similar reflectivity pattern as the nonaffected cornea. There was epithelial marsupialization evident in 2 of the 5 images. In the 4 patients with a clinical history of inflammation (bulbar hyperemia and pain), and in the 1 patient with active inflammation at the time of HR-OCT imaging, HR-OCT also demonstrated thinning with an intact epithelium. In contrast to the TMD group, in the group with signs of inflammation, a dense hyperreflective band was noted in the stroma directly below the epithelium in the area of thinning, suggestive of scarring and/or cellular infiltration. In patients with a clinical history of inflammation and corneal thinning, HR-OCT revealed a hyperreflective band directly under the epithelium in the area of thinning, which was not seen in patients with presumed noninflammatory melts and thinning.

OCT spectralis for terrien marginal degeneration diagnosis

PurposeTerrien marginal degeneration is a rare idiopathic form of corneal degeneration that affects peripheral cornea, it occurs at any age and 75% of patients are males. This condition is most commonly bilateral and asymmetric.Patients are often asymptomatic but they may also complain of irritation of the eye and progressive loss of visual acuity due to oblique astigmatism. Rarely the disease may lead to corneal perforation but may also occur spontaneously or secondary to trauma.The most important corneal modifications in Terrien marginal degeneration, frequently located superonasaly, are observed in the stroma showing yellow – white opacities composed of lipids with associated vascularization.Spectral Domain OCT because of its capacities to describe corneal anatomy might be useful in the diagnosis of the Terrien marginal degeneration.MethodsWe present a case of a 75 year old male who was examined and followed during several months in the department of ophthalmology, Lozano Blesa University Clinic Hospital, Zaragoza, Spain, with slit lamp, corneal topographic maps and spectral domain‐ OCT.ResultsSD‐OCT confirmed the peripheral corneal thinning seen with corneal topographic map and slit lamp. It showed intact epithelial and endothelial layers surrounding the stromal cavity formation, and a perforation of the endothelium underneath this cavity.ConclusionsWe point out the utility of spectral domain optical coherence tomography in the diagnosis and follow‐up of cavity formation in the peripheral cornea in Terrien marginal degeneration.

Terrien marginal degeneration presenting with corneal perforation

PurposeTerrien marginal degeneration is a slow‐progressing, bilateral but asymmetric degeneration of the peripheral cornea. The spontaneous corneal perforation is rare. To report a imminent corneal perforation as a presenting sign Terrien marginal degeneration, treated with amniotic membrane implant.MethodsA 70‐year‐old man presented with complaints of pain, redness,and decreased visión in the left eye (LE). Examination revealed peripheral corneal thinning 360º with superficial vascularization and secondary lipid keratopathy. There was an area of more thinning at the 5 o′clok position. His best‐corrected visual acuities (BCVAs) were 90°−4 + 4: 0.8 on the RE and 80°−3.75 + 4: 0.6 on the LE. Corneal topography with Orbscan of the LE revealed high oblique astigmatism with Sim K values of 48.75D at 140° and 43.25D at 50°. AS‐OCT showed corneal thinning and cavity formation with intact epithelial layer and affected endothelium in the thinned área.ResultsDue to the imminet corneal perforation was selected to make an amniotic membrane implant. Several circular layers of amniotic membrane rolled up on themselves and placed in the thinned área, fixing them with nylon 10‐0 suturing it to perilesional healthy cornea. The post‐operative AS‐ OCT reveals good adhesion of the amniotic membrane and corneal thickness recovery.ConclusionsTerrien marginal degeneration is an unusual cause for a spontaneous corneal perforation. Patients with this disorder should be warned about this possibility. Surgery (lamellar graft, amniotic membrabe implant) can preserve corneal integrity and is indicated when conventional options fail to maintain vision or if perforation is imminent.