Life under pressure: The role of ocular cribriform cells in preventing glaucoma.

Primary open-angle glaucoma is a multifactorial blinding disease often impacting the two pressure-sensitive regions of the eye: the conventional outflow pathway and the optic nerve head (ONH). The connective tissues that span these two openings in the globe are the trabecular meshwork of the conventional outflow pathway and the lamina cribrosa of the ONH. Resident cribiform cells of these two regions are responsible for actively remodeling and maintaining their connective tissues. In glaucoma, aberrant maintenance of the juxtacanalicular tissues (JCT) of the conventional outflow pathway results in ocular hypertension and pathological remodeling of the lamina cribrosa results in ONH cupping, damaging retinal ganglion cell axons. Interestingly, cells cultured from the lamina cribrosa and the JCT of the trabecular meshwork have similarities regarding gene expression, protein production, plus cellular responses to growth factors and mechanical stimuli. This review compares and contrasts the current knowledge of these two cell types, whose health is critical for protecting the eye from glaucomatous changes. In response to pressure gradients across their respective cribiform tissues, the goal is to better understand and differentiate healthy from pathological behavior of these two cell types.

Choroidal melanoma recurrence after episcleral brachytherapy and transpupillary thermotherapy.

A 68-year-old man diagnosed with choroidal melanoma (CM) in the right eye underwent treatment with episcleral brachytherapy (I125) and transpupillary thermotherapy. Ultrasound, computed tomography, and magnetic resonance imaging were performed and revealed ocular recurrence of CM. Treatment with extended enucleation was performed. Macroscopic and microscopic examinations revealed extraocular extension and malignant cells, respectively. Immunohistochemistry demonstrated tumoral Melan-A and HMB-45 expression. No cytogenic abnormalities were detected with fluorescence in situhybridization of tumor cells using probes against chromosomes 3q27 and 8q24. The patient underwent adjuvant external beam radiotherapy for treatment of residual tumor tissue. This case represents the first reported case of recurrent CM with no cytogenetic abnormalities and the absence of metastatic disease, despite a number of the poorest prognostic factors.

Choroidal melanoma recurrence after episcleral brachytherapy and transpupillary thermotherapy / Recorrência melanoma de coroide após a braquiterapia episcleral e termoterapia transpupilar

ABSTRACT A 68-year-old man diagnosed with choroidal melanoma (CM) in the right eye underwent treatment with episcleral brachytherapy (I125) and transpupillary thermotherapy. Ultrasound, computed tomography, and magnetic resonance imaging were performed and revealed ocular recurrence of CM. Treatment with extended enucleation was performed. Macroscopic and microscopic examinations revealed extraocular extension and malignant cells, respectively. Immunohistochemistry demonstrated tumoral Melan-A and HMB-45 expression. No cytogenic abnormalities were detected with fluorescence in situhybridization of tumor cells using probes against chromosomes 3q27 and 8q24. The patient underwent adjuvant external beam radiotherapy for treatment of residual tumor tissue. This case represents the first reported case of recurrent CM with no cytogenetic abnormalities and the absence of metastatic disease, despite a number of the poorest prognostic factors.

RESUMO Um homem de 68 anos de idade com diagnóstico de melanoma de coroide no olho direito foi submetido a tratamento com braquiterapia episcleral (I125) e termoterapia transpupilar. Ultrassonografia, tomografia computadorizada e ressonância magnética foram realizadas para avaliar a presença de recorrência ocular ou doença sistêmica. Enucleação ampliada foi realizada para tratar a recorrência ocular. O exame macroscópico e microscópico revelou o tipo de célula tumoral e a extensão extraocular. Colorações por Melan-A e HMB-45 foram realizadas. A fluorescência por hibridização in situ com sondas para os cromossomos 3q27 e 8q24 não mostraram anormalidades citogenéticas. O paciente foi submetido a radioterapia externa adjuvante para o tratamento de tumor residual orbitário. Este caso representa a o primeiro relato de paciente sem anomalias citogenéticas e sem doença metastática, apesar de demonstrar alguns dos mais pobres fatores prognósticos.

The Connective Tissue Components of Optic Nerve Head Cupping in Monkey Experimental Glaucoma Part 1: Global Change.

PURPOSE: To characterize optic nerve head (ONH) connective tissue change within 21 monkey experimental glaucoma (EG) eyes, so as to identify its principal components. METHODS: Animals were imaged three to five times at baseline then every 2 weeks following chronic unilateral IOP elevation, and euthanized early through end-stage confocal scanning laser tomographic change. Optic nerve heads were serial-sectioned, three-dimensionally (3D) reconstructed, delineated, and quantified. Overall EG versus control eye differences were assessed by general estimating equations (GEE). Significant, animal-specific, EG eye change was required to exceed the maximum physiologic intereye differences in six healthy animals. RESULTS: Overall EG eye change was significant (P < 0.0026) and animal-specific EG eye change most frequent, for five phenomena (number of EG eyes and range of animal-specific change): posterior laminar deformation (21, -29 to -437 µm), laminar thickening (11, 20-73 µm) and thinning (3, -23 to -31 µm), scleral canal expansion (17, 20-139 µm), outward anterior (16, -16 to -124 µm) and posterior (17, -22 to -279 µm) laminar insertion migration, and peripapillary scleral bowing (11, 21-77 µm). Experimental glaucoma versus control eye laminar thickness differences were bimodal in behavior, being thickened in most EG eyes demonstrating the least deformation and less thickened or thinned in most EG eyes demonstrating the greatest deformation. CONCLUSIONS: Our postmortem studies retrospectively identify five connective tissue components of ONH "cupping" in monkey EG which serve as targets for longitudinally staging and phenotyping ONH connective tissue alteration within all forms of monkey and human optic neuropathy.

Papillary thyroid carcinoma: bilateral choroidal metastases with extrascleral extension.

Here, we present the case of a patient with bilateral choroidal metastases with extraocular extension in one eye. Metastasis of papillary thyroid carcinoma to the uvea is extremely rare, with only 6 patients reported in the literature. A 62-year-old man with a prior history of papillary thyroid carcinoma suffered the rapid loss of vision in his right eye. He had neovascular glaucoma, total retinal detachment, and a solitary choroidal mass. A month later, his left visual acuity also decreased because of a small macular choroidal mass. The right eye was enucleated and a nodular lesion over the sclera representing extraocular extension was observed. This tumor and the intraocular lesion were composed of papillary excrescences and cystic spaces and stained positively for thyroid transcription factor 1 and thyroglobulin, all confirming the diagnosis of metastatic papillary thyroid carcinoma. The tumor in the left eye was successfully treated with diode laser transpupillary thermotherapy. The patient expired within a month as a result of widespread pulmonary metastases. Papillary thyroid carcinoma may metastasize to the uvea bilaterally, cause rapid visual function loss, erode the sclera, and may extend outside the globe similar to choroidal melanoma. This aggressive ocular involvement was associated with a dismal prognosis in our patient.

[The study of opportunity of aqueous humor filtration increase after nondestructive laser exposure of sclera in the site of pars plana projection (experimental study)].

Increase of scleral water permeability due to formation of porous structure after exposure of pulsed periodic radiation of erbium-glass optical fiber laser with wave length 1,56 pm was demonstrated in experimental study of cadaver human eyes in vitro and eyes of experimental animals (rabbits) in vivo. Simultaneous complex laser exposure of pars plana and ciliary processes results in summation of morphological changes that provide decrease of aqueous humor secretion, uveal drainage and extension of suprachoroid space. A base for new noninvasive technology of nondestructive laser exposure in glaucoma treatment is established.

Papillary Thyroid Carcinoma: Bilateral Choroidal Metastases with Extrascleral Extension

Here, we present the case of a patient with bilateral choroidal metastases with extraocular extension in one eye. Metastasis of papillary thyroid carcinoma to the uvea is extremely rare, with only 6 patients reported in the literature. A 62-year-old man with a prior history of papillary thyroid carcinoma suffered the rapid loss of vision in his right eye. He had neovascular glaucoma, total retinal detachment, and a solitary choroidal mass. A month later, his left visual acuity also decreased because of a small macular choroidal mass. The right eye was enucleated and a nodular lesion over the sclera representing extraocular extension was observed. This tumor and the intraocular lesion were composed of papillary excrescences and cystic spaces and stained positively for thyroid transcription factor 1 and thyroglobulin, all confirming the diagnosis of metastatic papillary thyroid carcinoma. The tumor in the left eye was successfully treated with diode laser transpupillary thermotherapy. The patient expired within a month as a result of widespread pulmonary metastases. Papillary thyroid carcinoma may metastasize to the uvea bilaterally, cause rapid visual function loss, erode the sclera, and may extend outside the globe similar to choroidal melanoma. This aggressive ocular involvement was associated with a dismal prognosis in our patient.

Posterior (outward) migration of the lamina cribrosa and early cupping in monkey experimental glaucoma.

PURPOSE: To quantify the lamina cribrosa insertion into the peripapillary sclera and optic nerve pia in normal (N) and early experimental glaucoma (EEG) monkey eyes. METHODS: Perfusion-fixed optic nerve heads (ONHs) from 21 animals were digitally reconstructed three dimensionally and delineated. Anterior Laminar Insertion Position (ALIP), Posterior Laminar Insertion Position (PLIP), Laminar Insertion Length (LIL; distance between the anterior and posterior laminar insertions), and Scleral Thickness (at the Anterior Sub-arachnoid space) were calculated for each ONH. Animals were pooled into four groups based on the kill condition (N vs. EEG) and perfusion IOP (10, 30, or 45 mm Hg) of each eye: N10-N10 (n = 6), N30/45-N10 (n = 6), EEG10-N10 (n = 3), and EEG30/45-N10 (n = 6). Glaucomatous EEG versus N eye differences in each group and each animal were required not only to achieve statistical significance (P < 0.05) but also to exceed physiologic intereye differences within the bilaterally normal groups. RESULTS: ALIP was significantly posterior (outward) in the EEG compared with N10 eyes of the EEG30/45-N10 group and 5 of 9 individual EEG eyes (difference range, 12-49 µm). PLIP was significantly posterior in the EEG eyes of both EEG groups and in 6 of 9 individual EEG eyes (range, 25-83 µm). LIL ranged from 90 to 190 µm in normal eyes and was significantly increased within the EEG eyes of both EEG groups and in 7 of 9 individual EEG eyes (difference range, 30-47 µm). CONCLUSIONS: Posterior migration of the lamina cribrosa is a component of early cupping in monkey EEG.

Shrinkage of the scleral canal during cupping reversal in children.

PURPOSE: The mechanism of cupping reversal seen after lowering intraocular pressure (IOP) in pediatric glaucoma is unknown. Theories include forward movement of the lamina cribrosa or shrinkage of a stretched scleral canal. Our study aimed to quantify changes in optic disc size occurring in children who had undergone glaucoma surgery. DESIGN: Retrospective, single-center, observational case series. PARTICIPANTS: Children undergoing incisional surgery for pediatric glaucoma at the University of California, Davis. METHODS: The electronic charts of all patients with pediatric glaucoma were reviewed for the presence of RetCam digital optic nerve photographs (Clarity Medical Systems, Pleasanton, CA). Cases in which the photographs (baseline and follow-up after surgical intervention) were of sufficient quality were analyzed. The optic disc margin was outlined manually using ImageJ software. Inter-session changes in magnification were accounted for by drawing a control polygon joining 4 or 5 fixed landmarks (e.g., vessel crossings) to include a second larger area containing the optic nerve. The optic disc area (in pixels adjusted with the control polygon) was compared between baseline and follow-up images. MAIN OUTCOME MEASURES: Change in disc area between baseline and follow-up after surgery. RESULTS: We identified 29 eyes for which baseline and follow-up images were available for analysis. Fifteen eyes of 9 children showed clinically obvious cupping reversal. Fourteen eyes of 12 children showed no cupping reversal. Disc area decreased by 6.8% (95% confidence interval [CI], -10.0 to -3.3) in the obvious reversal group and increased by 4.3% (95% CI, +1.0 to +7.6) in the no reversal group after surgery (P < 0.0001; Student t test). Percent change in disc area is correlated to percent change in IOP (r=0.540; P=0.0025) and axial length (r=0.534; P=0.0028). CONCLUSIONS: When cupping reversal is clinically apparent after successful IOP-lowering surgery for congenital glaucoma, the scleral canal shrinks in area. In contrast, when cupping reversal is not observed, the scleral ring continues to enlarge, indicating ongoing stress on the optic nerve. Clinically obvious cupping reversal is less frequently observed in adults after surgery, which may reflect a lower elasticity of the scleral ring in adults compared with children. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Knockdown of zebrafish lumican gene (zlum) causes scleral thinning and increased size of scleral coats.

The lumican gene (lum), which encodes one of the major keratan sulfate proteoglycans (KSPGs) in the vertebrate cornea and sclera, has been linked to axial myopia in humans. In this study, we chose zebrafish (Danio rerio) as an animal model to elucidate the role of lumican in the development of axial myopia. The zebrafish lumican gene (zlum) spans approximately 4.6 kb of the zebrafish genome. Like human (hLUM) and mouse (mlum), zlum consists of three exons, two introns, and a TATA box-less promoter at the 5'-flanking region of the transcription initiation site. Sequence analysis of the cDNA predicts that zLum encodes 344 amino acids. zLum shares 51% amino acid sequence identity with human lumican. Similar to hLUM and mlum, zlum mRNA is expressed in the eye and many other tissues, such as brain, muscle, and liver as well. Transgenic zebrafish harboring an enhanced GFP reporter gene construct downstream of a 1.7-kb zlum 5'-flanking region displayed enhanced GFP expression in the cornea and sclera, as well as throughout the body. Down-regulation of zlum expression by antisense zlum morpholinos manifested ocular enlargement resembling axial myopia due to disruption of the collagen fibril arrangement in the sclera and resulted in scleral thinning. Administration of muscarinic receptor antagonists, e.g. atropine and pirenzepine, effectively subdued the ocular enlargement caused by morpholinos in in vivo zebrafish larvae assays. The observation suggests that zebrafish can be used as an in vivo model for screening compounds in treating myopia.

Hyperbaric oxygen therapy and the eye.

Hyperbaric oxygen therapy (HBOT) is a primary or adjunctive therapy for a variety of medical disorders including some involving the eye. This paper is the first comprehensive review of HBOT for ocular indications. The authors recommend the following as ocular indications for HBOT: decompression sickness or arterial gas embolism with visual signs or symptoms, central retinal artery occlusion, ocular and periocular gas gangrene, cerebro-rhino-orbital mucormycosis, periocular necrotizing fasciitis, carbon monoxide poisoning with visual sequelae, radiation optic neuropathy, radiation or mitomycin C-induced scleral necrosis, and periorbital reconstructive surgery. Other ocular disorders that may benefit from HBOT include selected cases of ischemic optic neuropathy, ischemic central retinal vein occlusion, branch retinal artery occlusion with central vision loss, ischemic branch retinal vein occlusion, cystoid macular edema associated with retinal venous occlusion, post-surgical inflammation, or intrinsic inflammatory disorders, periocular brown recluse spider envenomation, ocular quinine toxicity, Purtscher's retinopathy, radiation retinopathy, anterior segment ischemia, retinal detachment in sickle cell disease, refractory actinomycotiC lacrimal canaliculitis, pyoderma gangrenosum of the orbit and refractory pseudomonas keratitis. Visual function should be monitored as clinically indicated before, during, and after therapy when HBOT is undertaken to treat vision loss. Visual acuity alone is not an adequate measure of visual function to monitor the efficacy of HBOT in this setting. Ocular examinations should also include automated perimetry to evaluate the central 30 degrees of visual field at appropriate intervals. Interpretation of the literature on the efficacy of HBOT in treating ocular disorders is complicated by several factors: frequent failure to include visual field examination as an outcome measure, failure to adequately address the interval from symptom onset to initiation of HBOT, and lack of evidence for optimal treatment regimens for essentially all ocular indications. Because some ocular disorders require rapid administration of HBOT to restore vision, patients with acute vision loss should be considered emergent when they present. Visual acuity should be checked immediately, including vision with pinhole correction. If the patient meets the criteria for emergent HBOT outlined in the paper, normobaric oxygen should be started at the highest inspired oxygen fraction possible until arrangements can be made for HBOT.

Scleral edge, not optic disc or retina, is the primary site of injury in chronic glaucoma.

In chronic glaucoma, there is a gradual painless loss of vision, early manifestation of arcuate field defect and typical atrophy of the optic disc known as 'cupping'. Chronic glaucoma is classified into high-tension glaucoma (HTG) and normal-tension glaucoma (NTG). Although both types manifest with the same typical visual field defect and cupping of the optic disc, high-tension glaucoma has elevated intraocular pressure whereas in normal-tension glaucoma the intraocular pressure (IOP) is within the normal range (10-21 mmHg). There are several theories about the pathogenesis of chronic glaucoma ranging from high intraocular pressure directly damaging the optic disc to programmed death(apoptosis) of the ganglion cells of the retina. But none of them satisfactorily explain the manifestation of the early arcuate field defect which is a pathognomonic feature of both types of chronic glaucoma. This article focuses on two main issues. First, how and why the arcuate field defects are produced in the early stages of glaucoma and secondly to find out the common ground in the pathogenesis of both high and normal tension glaucoma. The early arcuate field defects are an important lead in discovering the pathogenesis of glaucoma, therefore if any factor or site which could not possibly produce initial sharply defined arcuate field defects was ruled out. This article presents an unconventional approach to the pathogenesis of glaucoma. Instead of looking for various factors causing glaucoma, emphasis was placed on determining the primary site of injury which could produce the initial arcuate field defects. Keeping the arcuate visual field defects in mind, the primary site of injury appears to be at the scleral edge and not the optic disc or the retina in chronic glaucoma. The border tissue which separates the sclera and choroid from the nerve fibers would atrophy due to chronic ischemia as a result of high intraocular pressure in HTG, whereas due to poor systemic circulation in NTG. In both types of chronic glaucoma, the ciliary circulation supplying the prelaminar and border tissue is compromised. As a result of atrophy of the border tissue, the optic disc sinks as a whole beginning temporally due to its tilted position and causing nerve fibers to stretch, kink, and cut at the scleral edge. This process of optic disc sinking would accelerate due to loss of nerve fibers which also provides anchorage to the optic disc. This cycle would continue until all the nerve fibers are cut at the scleral edge and the optic disc is destroyed.

Effects of novel ethacrynic acid derivatives on human trabecular meshwork cell shape, actin cytoskeletal organization, and transcellular fluid flow.

To determine efficacy and therapeutic index in the context of ocular hypotensive activity of the new ethacrynic acid (ECA) derivatives of the series (SA8,248 and SA8,389), 9,000 series (SA9,000, SA9,622 and SA9,995) and ticrynafen, we undertook a comparative evaluation of the dose-dependent effects of these compounds on human trabecular meshwork (HTM) cell shape, actin cytoskeletal organization, focal adhesions and transcellular fluid flow. Responses were either scored using an arbitrary scale of 1-5 or quantified. Compounds of the 9000 series (SA9,995>SA9,000>SA9,622) were found to be 14- to 20-fold more potent than ECA, ticrynafen or analogs from the 8,000 series (SA8,389>SA8,248) in terms of ability to induce cell shape alterations in HTM cells. Similarly, compounds of the 9,000 series (SA9,995>SA9,622>SA9,000) were found to be much stronger (2 to 20 fold) than ECA, ticrynafen or analogs of the 8000 series in terms of affecting decreases in actin stress fiber content in HTM cells. Analogs of the 9000 series (SA9,622>SA9,995>SA9,000) were also observed to be 8 to 10 fold more potent than ECA (SA8,389>ECA>SA8,248>ticrynafen) at eliciting decreases in cellular focal adhesions. Interestingly, analogs of the 9000 series (SA9,000>SA9,622>SA9,995) and SA8,248 demonstrated a huge increase (by many folds) in transcellular fluid flow of HTM cell monolayers as compared to ECA and ticrynafen. Collectively, these analyses revealed that the structural modification of ECA improves its ocular hypotensive efficacy, indicating that the SA9,000 series compounds might be promising novel ocular hypotensive drugs.

Preclinical evaluation of a novel episcleral cyclosporine implant for ocular graft-versus-host disease.

PURPOSE: To develop a local drug delivery system that provides therapeutic cyclosporine levels to treat lacrimal gland graft-versus-host disease after allogeneic hematopoietic stem cell transplantation. METHODS: Episcleral cyclosporine implants were manufactured with a silicone-based matrix design, and in vitro release rates were determined. Preclinical evaluation included toxicology (clinical examination, serial electroretinography, and histopathology) in normal rabbits and dogs, pharmacokinetics in normal rabbits, and pharmacodynamics in a canine model of aqueous tear deficiency and keratoconjunctivitis sicca. RESULTS: The cyclosporine implants showed sustained release of drug over time with in vitro assays. Histopathology showed normal ocular tissues in both dogs and rabbits 6 months after implantation. The cyclosporine implant produced lacrimal gland drug levels 1 to 2 log units higher than those reported with a variety of topical cyclosporine formulations and oral administration. The cyclosporine implant was effective in a canine model of keratoconjunctivitis sicca, with all animals able to discontinue topical cyclosporine and maintain normal Schirmer scores over a 6-month follow-up. CONCLUSIONS: This preclinical evaluation showed that the episcleral cyclosporine implant was safe, delivered potentially therapeutic cyclosporine levels to the lacrimal gland, and showed efficacy in a clinically relevant model of keratoconjunctivitis sicca. The episcleral cyclosporine implant shows promise in reducing the morbidity associated with lacrimal gland graft-versus-host disease after allogeneic hematopoietic stem cell transplantation. In addition, continuous release of cyclosporine in the subconjunctival space with the episcleral implant was an effective means of delivering drug to the ocular surface and may have potential in treating other ocular inflammatory diseases.

Gellan-based scleral implants of indomethacin: in vitro and in vivo evaluation.

Film-type scleral implants of indomethacin with gellan gum were prepared by solvent casting and evaluated for uniformities of thickness, weight, drug content, and surface pH. The effect of plasticizers like glycerol, propylene glycol (PG), and polyethylene glycol 200, and 400 on the void volume of free gellan films (placebo) was calculated from the water content of the films. The drug release from the prepared implants was determined using a static dissolution set-up developed and optimized in our laboratory. Based on the results of the void volume and initial drug release studies, glycerol and PG were selected as the plasticizers for the gellan-based implants. The morphology of the drug-free films (containing 10% and 40% of PG) and the drug-loaded films (before and after dissolution and crosslinked) was studied using scanning electron microscopy. Further, the effect of plasticizer concentration, gellan concentration, effect of crosslinking technique, and duration of crosslinking using calcium chloride on in vitro drug release characteristics were evaluated. Selected batches of the implants were subjected to pharmacodynamic studies, after scleral placement, in uveitis-induced (intravitreal injection of bovine serum albumin 50 microg/ml) rabbit eyes. The release of indomethacin from the prepared implants followed matrix diffusion kinetics with diffusion co-efficient (n) values ranging between 0.358 to 0.708 and seemed to depend on both gellan and plasticizer concentration. Surface crosslinking with 10% calcium chloride for 8 hr retarded drug release (1.42 times less than noncrosslinked implant) and was optimum. The pharmacodynamic studies showed a marked improvement in the various clinical parameters (congestion, keratitis, flare, clot, aqueous cells, and synechias) in the implanted eye compared with the control eye in the rabbits. The scleral implants survived up to 3 weeks in vivo.

Necrosis of the eyelids and sclera after retrobulbar anesthesia.

A 52-year-old man had loss of vision and black discoloration of the lids of the right eye after a retrobulbar injection of 3 mL lidocaine hydrochloride 2% (Xylocaine). Examination of the right eye revealed no light perception with extensive necrosis of the lids. Anterior segment examination revealed conjunctival pallor, corneal edema, and necrosis of the sclera. This is a previously unreported complication of retrobulbar anesthesia comprising ophthalmic artery occlusion with scleral melt, ocular ischemia, and eyelid necrosis.

Transscleral thermotherapy: short- and long-term effects of transscleral conductive heating in rabbit eyes.

OBJECTIVE: To determine the highest safe treatment temperature, at 30- and 60-second exposure durations, for transscleral thermotherapy (TSTT) of choroidal melanoma. METHODS AND DESIGN: Transscleral conductive heating was performed in 15 rabbits at 50 degrees C to 70 degrees C for 30 or 60 seconds. The thermal lesions in the ocular fundus were monitored for 4 months with ophthalmoscopic, photographic, and fluorescein angiographic examination. Histologic examination included polarized light microscopy. RESULTS: The effect of TSTT was similar for both exposure durations. Vascular occlusion in the retina and choroid developed at temperatures of 55 degrees C and higher. After heating at 60 degrees C, scleral collagen fibers developed a minimal undulation; at 65 degrees C, they became clearly undulated. The undulation resolved in the 3 to 4 months after heating. Heating at 70 degrees C caused persistent severe damage to the sclera. Retinal tears developed after heating at 65 degrees C and 70 degrees C. CONCLUSIONS: A temperature of 65 degrees C was found to be the highest temperature that did not cause permanent damage to the sclera at both exposure durations. A temperature of 60 degrees C may be the optimal temperature for TSTT of choroidal melanoma because retinal tears may develop at 65 degrees C. CLINICAL RELEVANCE: In TSTT, the temperature levels reached are cytotoxic for choroidal melanoma as well as intrascleral tumor cells. Occlusion of choroidal vessels induced by TSTT may contribute to tumor necrosis because these vessels serve as feeder vessels for the tumor.

Hyperbaric oxygen therapy for mitomycin C-induced scleral necrosis.

Intraoperative or postoperative use of mitomycin C is one of the treatment options to reduce the recurrence of pterygia. Scleral necrosis, a potentially blinding complication after mitomycin C use, has been among great concern in ophthalmic practice. A patient is presented in whom scleral necrosis developed 20 days after a pterygiectomy with bare sclera technique was performed, followed by the application of 0.4 mg/mL of topical mitomycin C eye drops for 3 weeks. After conjunctival flap failures the patient was treated with hyperbaric oxygen therapy. The sclera revascularized and returned to near normal thickness after 24 sessions of hyperbaric oxygen therapy. This case demonstrates that it is an effective, novel treatment. [Ophthalmic