Tumor necrosis factor alpha induces a serotonin dependent early increase in ciliary beat frequency and epithelial transport velocity in murine tracheae

The tracheal epithelium prevents via its highly effective clearance mechanism the contamination of the lower airways by pathogens. This mechanism is driven by ciliary bearing cells which are not only in contact with the gas phase; in addition they are also influenced by inflammatory mediators. These mediators can alter the protective function of the epithelium. Since the pro-inflammatoric cytokine tumor necrosis factor-α (TNF-α) plays a pivotal role within the inflammatory cascade, we investigated its effect onto the tracheal epithelium measured by its ciliary beat frequency and the particle transport velocity. In organ explant experiments the ciliary beat frequency and the particle transport velocity were measured under the application of TNF-α using tracheae from male C57BL6J mice. We observed a dose dependent TNF-α induced increase of both particle transport velocity and ciliary beat frequency. Knock out mice experiments made evident that the increase was depended on the expression of tumor necrosis factor receptor 1 (TNF-R1). The increases in ciliary beat frequency as well as the accelerated particle transport velocity were either inhibited by the unspecific serotonin antagonist methysergide or by cyproheptadine a specific 5-HT2 receptor antagonist. Thus, acetylcholine antagonists or nitric oxide synthase (NOS) inhibitors failed to inhibit the TNF-α induced activation. In conclusion, TNF-α may play a pivotal role in the protection of lower airways by inducing ciliary activity and increase in particle transport velocity via TNF-R1 and 5-HT2 receptor.

[Spasm of accommodation]

Spasm of accommodation refers to prolonged contraction of the ciliary muscle, most commonly causing pseudomyopia to varying degrees in both eyes by keeping the lens in a state of short sightedness. It may also be manifested as inability to allow the adaptation spasticity prevailing in the ciliary muscle relax without measurable myopia. As a rule, this is a functional ailment triggered by prolonged near work and stress. The most common symptoms include blurring of distance vision, varying visual acuity as well as pains in the orbital region and the head, progressing into a chronic state. Cycloplegic eye drops are used as the treatment.

Ghrelin in ocular pathophysiology: from the anterior to the posterior segment

Ghrelin is a 28 amino acid acylated peptide produced in several organs that binds the growth hormone secretagogues receptor type 1a (GHSR-1a). It acts over a wide range of systems, e.g. the endocrine, cardiovascular, musculoskeletal and immune systems and the eye. The aim of this work is to review the physiologic and pathologic implications of the ghrelin-GHSR-1a in the eye. A systematic revision of studies published between 2000 and 2013 in English, Spanish or Portuguese in MEDLINE, EMBASE and Scopus was performed. Search words used included: ghrelin, GHSR-1a, ocular production, iris muscular kinetics, ciliary body, glaucoma, retinopathy and uvea. The production of ghrelin by the ocular tissue has been detected both in the anterior and posterior segments, as well as the presence of GHSR-1a. This peptide promotes the relaxation of the iris sphincter and dilator muscles, being this effect independent from GHSR-1a and dependent on prostaglandins release in the first case and dependent on GHSR-1a in the second. Regarding ocular pathology, ghrelin levels in the aqueous humor appear to be decreased in individuals with glaucoma. Moreover, ghrelin has been shown to decrease the intraocular pressure in animal models of ocular hypertension through GHSR-1a. In the posterior segment, the ghrelin-GHSR-1a system interferes with the development of oxygen-induced retinopathy, being protective in the vaso-obliterative phase and deleterious in the vaso-proliferative stage of the disease. Thus, the ghrelin-GHSR-1a system presents as a possible local regulatory mechanism in the eye, with pathophysiological implications, constituting a target for future clinical and therapeutic research and interventions.

[Accommodation examination in myopia associated with nondifferentiated connective tissue dysplasia]

Features of accommodative response in children with myopia associated with nondifferentiated connective tissue dysplasia (NCTD) were studied using computered accommodography. A variety of accommodative response patterns were found in myopia associated with NCTD, that is indicative of a great functional potential of ciliary muscle. Theoretic side is discussed for normal accommodative response and for muscle fibers hyperfunction as well.

[Multifocal, toric, and aspheric intraocular lenses for glaucoma patients]

Cataract surgery has greatly developed over recent years, mainly due to the introduction and availability of newer intraocular lenses (IOLs) with modern platforms and better visual outcomes. Aspheric, multifocal, and toric lenses are among these new lenses. Glaucomatous eyes have a number of particularities that can influence the way these implants are indicated and used. Contrast sensitivity is usually reduced in eyes with glaucoma and, sometimes, a poor IOL choice can aggravate the disease. Small pupils and zonular weakness are frequently associated with certain types of glaucoma (e.g. pseudoexfoliative glaucoma) and can limit the indication of some of the newer IOLs. Lastly, in some cases of combined surgery, the postoperative axial length and anterior chamber depth can change after surgery, requiring adjustments in the IOL power calculation. The purpose of this article is to quickly review some of the specific features of cataract surgery in the glaucomatous eye, some of the IOL choices, and the necessary precautions for these eyes.

Emmetropization in the primate eye

A theory to explain the mechanism of emmetropization of the human eye is reviewed and updated. The theory is probably also valid for the primate eye. It is proposed that the ciliary muscle-choroid layer behaves like a solid sheet of smooth muscle, so that it is able to resist part of the intraocular pressure and to regulate scleral stretch in the growing eye. It is suggested that the autonomic nervous system and stress play a role in the development of ametropia and that interference with the cortical-subcortical control of the ciliary muscle may prevent emmetropization.

Presbyopietherapie mit Femtosekundenlaser

Presbyopia is by far the most common refractive error worldwide, with no permanent therapeutic option available. All efforts to restore accommodation by the use of surgery have not led to a generally accepted therapy. However, there is evidence from an animal model that the use of a femtosecond (fs) laser might influence the modulus of elasticity in the lens. Fs-laser impulses can create intralenticular disruption in animal eyes as well as human cadaver lenses and improve elasticity. The concept of treating presbyopia with fs-laser requires a new, complex theory combining the optical and the mechanical aspects of accommodation in the eye. Diagnostic tools for measuring optical change in power and geometrical modification as the eye views from far to near are needed to obtain objective clinical data. A non-invasive treatment of presbyopia to restore accommodation might be possible in the future.

Accommodation and presbyopia: the ciliary neuromuscular view

Presbyopia (literally, "old eye"), the age-related loss of the ability to accommodate, is the most common ocular affliction in the world. Although the lens no doubt has a major role in presbyopia, altered lens function could be in part secondary to extralenticular age-related changes, such as loss of ciliary body forward movement. Centripetal ciliary muscle movement does not seem to decrease significantly with age. Loss of elasticity of the ciliary muscle posterior attachments may be an important factor contributing to presbyopia. Even if loss of ciliary muscle mobility is not causally related to presbyopia, it may limit the performance of putatively accommodating intraocular lenses now being developed by academic and industrial groups.

The influence of cycloplegia in objective refraction

The purpose of this study was to compare refractions measured with an autorefractor and by retinoscopy with and without cycloplegia. The objective refractions were performed in 199 right eyes from 199 healthy young adults with a mean age of 21.6 +/- 2.66 years. The measurements were performed first without cycloplegia and repeated 30 min later with cycloplegia. Data were analysed using Fourier decomposition of the power profile. More negative values of component M and J(0) were given by non-cycloplegic autorefraction compared with cycloplegic autorefraction (p < 0.0001). However more positive values for the J(45) vector were given by non-cycloplegic autorefraction, although this difference was not statistically significant (p = 0.233). By retinoscopy, more negative values of component M were obtained with non-cycloplegic retinoscopy (p < 0.0001); for the cylindrical vectors J(0) and J(45) the retinoscopy without cycloplegia yields more negative values (p = 0.234; p = 0.112, respectively). Accepting that differences between cycloplegic and non-cycloplegic retinoscopy are only due to the accommodative response, the present results confirm that when performed by an experienced clinician, retinoscopy is a more reliable method to obtain the objective starting point for refraction under non-cycloplegic conditions.

Sympathetic innervation of ciliary muscle and oculomotor function in emmetropic and myopic young adults

PURPOSE

Evidence exists for an additional inhibitory accommodative control system mediated by the sympathetic branch of the autonomic nervous system (ANS). This work aims to show the relative prevalence of sympathetic inhibition in young emmetropic and myopic adults, and to evaluate the effect of sympathetic facility on accommodative and oculomotor function.

METHODS

Profiling of ciliary muscle innervation was carried out in 58 young adult subjects (30 emmetropes, 14 early onset myopes, 14 late onset myopes) by examining post-task open-loop accommodation responses, recorded continuously by a modified open-view infrared optometer. Measurements of amplitude of accommodation, tonic accommodation, accommodative lag at near, AC/A ratio, and heterophoria at distance and near were made to establish a profile of oculomotor function.

RESULTS

Evidence of sympathetic inhibitory facility in ciliary smooth muscle was observed in 27% of emmetropes, 21% of early-onset myopes and 29% of late-onset myopes. Twenty-six percent of all subjects demonstrated access to sympathetic facility. Closed-loop oculomotor function did not differ significantly between subjects with sympathetic facility, and those with sympathetic deficit.

CONCLUSIONS

Emmetropic and myopic groups cannot be distinguished in terms of the relative proportions having access to sympathetic inhibition. Presence of sympathetic innervation does not have a significant effect on accommodative function under closed-loop viewing conditions.

[Study of an accommodational response after surgical correction of myopia with an ICL intraocular lens]

The paper analyzes the nature of an accommodational response in 11 patients (19 eyes) before and after surgical correction of myopia with ICL intraocular lenses (IOLs). Rapid and slow accommodational responses were studied to different values of an accommodation stimulus (from 1.0 to 3.0 diopters). The implanted IOLs were found to have no effect on the performance of the ciliary muscle. Its compensatory enhancement occurs after implantation, which ensures the normal performance of the accommodation apparatus.

Changes in the shape of the anterior and posterior corneal surfaces caused by mydriasis and miosis

PURPOSE

To evaluate changes in the anterior and posterior corneal shape, corneal thickness, and anterior chamber depth (ACD) caused by mydriasis or miosis using scanning-slit corneal topography.

SETTING

Department of Ophthalmology, Iwate Medical University School of Medicine, Iwate, Morioka, Japan.

METHODS

Twenty-eight eyes of 28 healthy volunteers with refractive errors of -6.00 to +0.25 diopters were studied. One eye of each subject had instillation of tropicamide-phenylephrine hydrochloride (Mydrin P) to obtain mydriasis and of pilocarpine hydrochloride 2% (Sanpilo) to obtain miosis. To assess the corneal shape, the best-fit sphere (BFS), axial power, and tangential power were measured for the anterior and posterior corneal surfaces before and after mydriasis and before and after miosis using scanning-slit corneal topography (Orbscan version 3.0, Orbtek, Inc.). The pupil size, corneal thickness, and ACD were also examined before and after mydriasis and before and after miosis.

RESULTS

The mean age of the patients was 31.1 years +/- 5.6 (SD) (range 20 to 46 years). The anterior BFS changed from a mean of 8.04 +/- 0.3 mm at the time of mydriasis to a mean of 8.00 +/- 0.3 mm at the time of miosis. The posterior BFS changed from 6.53 +/- 0.3 mm to 6.46 +/- 0.3 mm, respectively. Thus, the anterior and posterior cornea became significantly steeper after miosis (P<.01). The ACD was significantly more shallow after miosis than after mydriasis. However, there was no significant difference in corneal thickness after mydriasis or miosis.

CONCLUSIONS

The anterior and posterior corneal shapes changed as a result of mydriasis and miosis, and the refractive power of the cornea significantly increased after miosis. To date, changes in refractive power from changes in pupil size have been attributed to a change in the refractive power of the crystalline lens; however, it is now thought that changes in corneal refractive power also occur.

Ciliary staphyloma: very rare sequelae of conjunctival rhinosporiodosis

The main ocular manifestation of rhinosporiosis is lid or conjunctival infection. Conjunctival rhinosporiodosis is very rately causing sclera necrosis. A patient named Shumi (8 years), D/O.- Rukan Uddin of Rupchandrapur, Atpara, Netrokona admitted on 09/03/2003 in the department of Ophtalmology, Mymensingh Medical College Hospital with complains of mass in right eye looks externally like a growth in upper lid and mild dimness of vision of right eye. On examination, it was found that she got VAR : 6/24 and having a shaphyloma near 12-00 O'clock position with a mass adjacent to it which was identified as rhinosporiodosis after excisional biopsy. No history of ocular trauma or any other ocular disease was found.

The autonomic control of accommodation and implications for human myopia development: a review

Prolonged nearwork has long been associated with myopia development, however, there is no well described linking mechanism. One theory suggests that if accommodation accuracy during nearwork is not maintained, the defocused retinal image leads to myopia development. Here we review the findings of research aimed at determining whether the autonomic inputs to the ciliary smooth muscle are involved in this type of environmental myopia. We examine whether an autonomic imbalance could be a precursor to axial elongation and the resulting myopia. Accommodation responses, such as tonic accommodation and nearwork-induced accommodative adaptation, as a function of refractive error, are described in relation to an autonomic imbalance model. The collective results of this research point to anomalous accommodation responses, possibly as a result of underlying anomalous autonomic input to the ciliary muscle, being involved in myopia development and progression.

Angle-closure glaucoma: impact, etiology, diagnosis, and treatment

PURPOSE OF REVIEW

Recent studies underscore the importance of angle-closure glaucoma (ACG) as a cause of world blindness. A major contribution in assessing the true impact of this disease has been an article estimating the number of persons with occludable angles, angle closure, and blindness from ACG in China as 28.2 million, 9.1 million, and 1.7 million, respectively. Although these numbers are based on data from Singapore and Mongolia, which may be applied to China only with caution, they emphasize the blinding potential of ACG, which is three times as likely to be associated with blindness as open-angle glaucoma (OAG).

RECENT FINDINGS

Recent reports in the Chinese literature on ACG prevalence suffer from definitional problems that would appear to lead to systematic overestimates of ACG prevalence and underestimates of OAG prevalence. Nonetheless, data from studies by Chinese investigators further emphasize the strong association between ACG and blindness, with fully 16% of subjects with ACG blind in one report-a far higher proportion than for OAG in China and elsewhere. The importance of topiramate as a cause of secondary angle closure has recently been understood, in part, because of a series of 19 such cases reported by investigators at the Food and Drug Administration.

SUMMARY

Angle closure in this setting appears to be caused by uveal effusion and anterior rotation of the ciliary body with resultant closure of the angle. The condition is not always responsive to laser iridectomy, and elimination of the causative agent appears to be critical. Ultrasonic biomicroscopy is a potential new diagnostic modality for ACG, allowing the measurement of novel parameters, such as the angle opening distance (AOD) at 500 microm (AOD 500). The efficacy of such parameters in improving screening for ACG can only be established by prospective studies of potentially at-risk eyes. A number of novel treatments for AC and angle closure have recently been proposed, including cataract extraction, paracentesis, and argon laser iridoplasty. As with proposed new diagnostic modalities, the efficacy of these treatments remains to be demonstrated with prospective studies, ideally organized in a controlled, randomized fashion.

Incidence of elderly eye injuries in automobile crashes: the effects of lens stiffness as a function of age

The purpose of this paper is to elucidate the incidence of eye injuries with respect to occupant age in frontal automobile crashes as well as to investigate possible injury mechanisms of the elderly eye and the effects of lens stiffness. The National Automotive Sampling System was searched from years 1993-2000 for three separate occupant age groups of 16-35 years old, 36-65 years old, and 66 years old and greater in order to compare the total number of weighted occupants who sustained an eye injury to the number of occupants who sustained an eye injury per age group. Three separate impact scenarios simulating a foam particle (30 m/s), a steering wheel (15 m/s), and an air bag (67 m/s), were applied to a finite element eye model in order to elucidate the effects of aging on the eye when subjected to blunt trauma. The lens stiffness of the model was varied according to human lens stiffness values determined for each age group. Occupants aged 66 years old and greater were two to three times more likely to incur an eye injury than younger occupants. The computational eye model demonstrated that increased risk was related to the increasing stiffness of the lens, producing up to a 120% larger stress in the ciliary body.

Modelling the mechanics of accommodation and presbyopia

Finite element methods have been used to compute the expected relationship between changes in ciliary body diameter and the change in refractive power implied by the change in geometry of the human ocular lens, using values for the material properties and initial geometry taken from the literature (notably the slit lamp photography of Brown (1973) and the studies by Fisher (1969) of the lens material properties). The results show that if the non-linearity associated with the changing geometry is taken into account the lens does not respond to ciliary body stretch by an increase in power [as recently claimed by Schachar et al. (1993), but in the conventional way with a decrease in power. The models show a decrease in the amplitude of accommodation between the age of 29 and 45 years (using Brown's data, 1973), but using Brown's data for the 11-year-old eye leads to the paradoxical conclusion that accommodation amplitude in this eye would have been small. In the process of carrying out the modelling, we have examined the consistency of the published measurements and also the validity of the mathematical methods used in interpreting them, and this analysis suggests that further work is needed before one can be confident that the assumptions about geometry and material properties on which the modelling is based are sound.

Expulsive hemorrhage before phacoemulsification

A 65-year-old white man who was scheduled for cataract extraction experienced a sudden increase in intraocular pressure (IOP) with flattening of the anterior chamber immediately after the anterior capsule incision. The eye was sutured, and because no decrease in pressure was noted, surgery was postponed. The presence of the cataract prevented ophthalmoscopic examination. Echographic examination revealed a hemorrhagic choroidal detachment with involvement of the ciliary body. The patient was examined regularly until the choroidal detachment disappeared 4 weeks later. He then had uneventful phacoemulsification and intraocular lens implantation.

Chemokine gene expression in iris-ciliary body during experimental autoimmune uveoretinitis

PURPOSE

To evaluate, through differential gene expression of chemokines in iris-ciliary body (I/CB), the extent to which leukocyte recruitment to the ocular anterior segment participates in the pathogenesis of experimental autoimmune uveoretinitis (EAU) in mice.

METHODS

B10.A mice were immunized with 50 microg of interphotoreceptor retinoid binding protein (IRBP) mixed with complete Freund's adjuvant. Aqueous humor (AqH) was collected at 0, 11, 17, and 28 days and assayed for leukocyte content and protein levels. Enucleated eyes were subjected to histologic analysis. Chemokine gene expression in I/CB was determined at these same time points by a multiprobe ribonuclease protection assay (RPA) system.

RESULTS

Inflammation was detected in the anterior chamber (AC) at 11 days and leukocyte recruitment continued thereafter. Polymorphonuclear neutrophils (PMN) were the predominant cell type in the AC, whereas macrophages/monocytes and lymphocytes were predominant in the retina/subretinal space at 17 days. Peak gene expression of macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, and MIP-2 and interferon-gamma-inducible protein of 10 kd (IP-10) was detected in I/CB on day 11, whereas peak expression of RANTES and eotaxin was observed at 17 days.

CONCLUSIONS

Early I/CB peak expression of mRNA for MIP-2 followed by PMN recruitment into the AC, suggests that PMN may play an important role in EAU pathogenesis.

Presbyopia, accommodation, and the mature catenary

OBJECTIVE

To demonstrate a plausible explanation of aging changes and to reduce the controversy relative to accommodation by using a mechanical model of the catenary theory of lens change. MECHANICAL MODELING: A mechanical model was used to simulate a human lens in both the accommodated and unaccommodated state to demonstrate changes in the mechanism of accommodation with age.

METHODS

Fluid-filled latex balloons were supported by a plastic wrap hammock to form a catenary that models the human lens. Increasing volumes were used to simulate that of the aging lens, and variations in curvature were measured.

MAIN OUTCOME MEASURES

The degree of curvature of a simulated anterior lens surface was measured and compared with mathematical modeling of its optical surface based on the catenary hydraulic suspension theory.

RESULTS

The measurements showed that accommodative loss and other features such as mass displacement, reproducible lens surfaces, and zonule support are consistent with the catenary theory of accommodation and an increasing lens volume with age.

CONCLUSIONS

The catenary theory of accommodation provides a basis for evaluating age changes of the human lens. Variable results with surgical procedures for presbyopia are also predictable with the model. These results can be used to provide a basis for intraocular lens design.

Theory behind surgical correction of presbyopia

This relatively new procedure is interesting, promising, and appears to be safe. These issues are currently being evaluated by the US FDA and in several other countries, most notably Canada. The procedure is based on Ronald A. Schachar's new theory of how accommodation occurs. The clinical course of the patients and the new wavefront analysis appear to support the theory. Regardless of the exact mechanism, clinically, the patients read and behave as though they have had their accommodation restored. The author certainly has been very impressed and excited with the results in his patients whose surgeons he has proctored.

[Accommodative lens implant]

PROBLEM

To date, approaches to restore accommodation following cataract surgery have been based on the principle of a liquid or solid implant that moves within the capsular bag and thereby changes the optical characteristics of the eye. However, these implants have been associated with shrinking and fibrosis of the capsular bag, a problem that will not be solved in the foreseeable future.

APPROACH

If accommodation is effected by shifting the whole capsule including its contents on the optical axis, capsular fibrosis will virtually no longer play a role. In order to execute this shift via the neuronal feedback mechanisms of the ciliary muscle in a controlled way, radial zonular forces or movements must be transformed into axial ones, which is possible by means of tiny permanent magnets. This paper describes the basic aspects of such an implant. The dependence of accommodation on all relevant parameters is quantified in a computer simulation.

CONCLUSION

The implant described appears to be practicable with justifiable technical and surgical efforts.

Contact trans-scleral diode laser cyclophotocoagulation treatment for refractory glaucomas in the Indian population

PURPOSE

This study aimed to evaluate the clinical efficacy of contact diode trans-scleral cyclophotocoagulation (TSCPC) for treatment of refractory glaucomas.

METHOD

Fifty two eyes of 52 patients, (post-penetrating keratoplasty glaucoma: 16 eyes; adherent leucoma with secondary glaucoma: 8 eyes; aphakic glaucoma: 6 eyes; neovascular glaucoma: 6 eyes; narrow angle glaucoma: 6 eyes; and other secondary glaucomas: 10 eyes) were followed up from 3.5-18 months (average 12 months) after TSCPC. The treatment parameters using the contact G probe were--energy: 3-4J; area: 40 spots spread over 360 degrees; site: 1.2-1.5 mm posterior to limbus. Retreatments (22 eyes; 42%) were given whenever intraocular pressure (IOP) exceeded 22 mmHg despite maximum tolerable topical therapy.

RESULTS

IOP decreased from a baseline of 44.7 (+/- 7.3) mmHg to 15 (+/- 3.7) mmHg at first week and was 15.2 +/- (8.2) mmHg at the last follow up. Successful control of IOP (< 22 mmHg) occurred in 30 (58%) eyes after a single treatment and in 48 (92%) eyes following retreatment. Complications included reduction in visual acuity from light perception (LP) only to no light perception (NLP) in two eyes and phthisis bulbi in one eye.

CONCLUSION

Contact trans-scleral diode laser cyclophotocoagulation is effective in lowering IOP in eyes with intractable glaucoma with few side effects in Indian subjects.

Transient acute myopia induced by antilymphocyte globulins

Acute onset of transient myopia may be induced by several drugs, different mechanisms having been described. We report the occurrence of such an event after intravenous administration of equine antilymphocyte globulins in a patient treated for aplastic anemia. Clinical ocular examination revealed no other abnormality, and ultrasonography disclosed no swelling of the ciliary body. The drug-induced myopia resolved completely after instillation of topical cyclopentolate, suggesting that its mechanism was the occurrence of a ciliary spasm. Acute myopia is a rare event and, to the authors' knowledge, this represents the first case described as being induced by antilymphocyte globulins.

Ciliary body PDT in pigmented rabbit eyes: effect of single and repeated treatment

PURPOSE

To investigate the morphologic and hypotensive effect of contact transscleral ciliary body PDT in pigmented rabbit eyes.

METHODS

The right eyes of 33 pigmented rabbits were irradiated using chloraluminum sulfonated phthalocyanine as photosensitizer and a diode laser (670 nm) as the light source. Twenty-five animals received a single treatment. Eight animals received a second treatment 13 days after the first one. Photosensitizer was administered by means of continuous intravenous infusion. Ciliary body was irradiated transsclerally by means of an optic fiber applied on the corneoscleral limbus. In all cases 14-16 laser applications were performed to cover 360 degrees of the ciliary body. Animals were followed for a maximum of 30 days by means of tonometry and biomicroscopy. Retreatments were performed using the same irradiation protocol. At the end of the follow up time animals were sacrificed and their were eyes prepared for light and electron microscopy.

RESULTS

Transscleral ciliary body PDT resulted in significant but temporary reduction of IOP in all cases. The effect lasted about two weeks. Retreatment led to a new significant drop of the IOP, which lasted about two weeks again. In histological examination the initial effect was vascular thrombosis, followed by edema and disintegration of the ciliary epithelial layers. In all cases the appearance of the ciliary body had returned to normal 15 days after irradiation.

CONCLUSION

Contact transscleral PDT with the treatment parameters used in this study results in significant but temporary functional and morphological alteration in pigmented rabbits ciliary body.

[Results after cyclodiathermy: report on 29 eyes]

BACKGROUND

Persisting angle-closure glaucomas with circular anterior synechia and lost anterior chamber are at the moment an unsolved therapeutical problem. Antiglaucomatous anterior cyclodiathermy is a last therapeutical option to serve the eye.

PATIENTS AND METHODS

We retrospectively examined the results and the complications of 29 eyes, which were consecutively treated with anterior cyclodiathermy between 1992 and 1998.

RESULTS

We found a significant decrease of the intraocular pressure (IOP) during mean follow-up of 10 month, reduction of antiglaucoma medication, no change of visual acuity and no severe complications (no phthisis bulbi, no severe intraocular hemorrhage, no sympathetic ophthalmia).

CONCLUSION

Anterior cyclodiathermy is a successful treatment for selected patients with severe forms of glaucoma, if other operation techniques and antiglaucoma medication fail to decrease the IOP.

Plateau iris syndrome: changes in angle opening associated with dark, light, and pilocarpine administration

PURPOSE

To report changes in angle configuration associated with dark, light, and pilocarpine administration in plateau iris syndrome.

METHOD

In 10 eyes of 10 patients with plateau iris syndrome and persistent narrow angles after patent peripheral Nd:YAG laser iridotomy, ultrasound biomicroscopy was used to image variations in angle opening, iris thickness, and trabecular-ciliary process distance. Measurements were taken in the dark, in full room light, and after administration of pilocarpine 2%.

RESULTS

Average angle opening distance increased in the light compared with the dark (113+/-34 microm vs. 22+/-34 microm, P = .0001) and increased further after pilocarpine administration (171+/-52 microm vs. 113+/-34 microm, P = .0034). Average iris thickness decreased in the light compared with the dark (338+/-34 microm vs. 436+/-58 microm, P = .0009) and decreased further after pilocarpine administration (253+/-48 microm vs. 338+/-34 microm, P = .0002). Average trabecular meshwork-ciliary process distance measurements were smaller than normal and did not change significantly in the light compared with the dark (481+/-42 microm vs. 464+/-44 microm, P = .4001) or after pilocarpine administration compared with light (451+/-67 microm vs. 481+/-42 microm, P = .1304).

CONCLUSIONS

In plateau iris syndrome, anteriorly located ciliary processes support the peripheral iris. Changes in angle opening in dark and light are solely related to changes in iris thickness. Pilocarpine produces iris thinning and is an effective method of opening the angle. Ultrasound biomicroscopy can be used to perform a darkroom provocative test, which provides information on whether the angle anatomically closes in the dark.

[The efficacy of training the accommodation muscle using the AT-1 Accomodotrainer]

A new modification of an AT-1 device for training of the ciliary muscle is described and the results of individual treatment by this device are analyzed. The device was used by 110 patients (220 eyes) aged 8-20 years with slight and medium myopia (group 1, 71 patients) and with slight hypermetropia with an accommodation spasm (group 2, 39 patients). After training visual acuity without correction improved in 71.5% cases in group 1 and in 95.6% in group 2. The relative accommodation reserves improved in 78.6 and 98.5% cases, respectively. The device is simple and reliable and easy to use, which recommends it as a trainer for maintenance therapy at home and as a component of multiple-modality treatment in an inpatient setting.

Audible pops during cyclodiode procedures

PURPOSE

This study was conducted to determine the incidence of intraocular uveal microexplosions ("pops") during contact diode laser transscleral cyclophotocoagulation (cyclodiode) and to analyze the influence of pop occurrence on results and postoperative complications.

METHODS

Cyclodiode treatment (1.5-2 W x 2 seconds over 270 degrees) was performed in 43 consecutive patients (43 eyes) with uncontrolled glaucoma who had not undergone previous ciliary ablation. Mean duration of follow-up evaluation was 12.7 months (range, 9-18 months). These eyes included 31 seeing eyes, in which intraocular pressure (IOP) reduction was indicated to preserve visual acuity (therapeutic group) and 12 blind eyes, in which IOP reduction was advisable to relieve pain (palliative group). Success was defined as a final IOP > or = 5 mmHg and < or = 21 mmHg in seeing eyes, and as the resolution of pain in blind eyes. Potential factors evaluated for intraoperative pop occurrence included patient age, gender, iris color, glaucoma diagnosis, preoperative IOP, and number of previous surgical procedures used to treat glaucoma.

RESULTS

In the group receiving therapeutic treatment, mean +/- standard deviation (SD) IOP was 41.8 +/- 12.7 mmHg before surgery and 19.2 +/- 8.3 mmHg after surgery; the success rate in this group was 83.9%. In the group receiving palliative treatment, mean IOP was 55.4 +/- 13.7 mmHg before surgery and 21.1 +/- 13.4 mmHg after surgery; success rate was 83.3% in this group. Intraoperative microdisruptions occurred in 48.8% of the cases during the first laser application; 67.5% of these occurred in the superior half of the eye. No significant difference in rate of intraoperative pop was observed between patients after one cyclodiode session and those eyes that underwent additional sessions. Mean baseline IOP was significantly higher in patients with intraoperative occurrence of pops. An audible pop was more common in the group undergoing palliative treatment. Intraoperative occurrence of pops was associated with a greater severity of postoperative iridocyclitis. All patients with postoperative hyphema also had pops during surgery. No significant difference in the success rate was found between patients in whom intraoperative pops did and did not occur.

CONCLUSION

Choroidal vaporization is significantly more common in patients with higher baseline IOP. Occurrence of pops also is associated with more severe postoperative inflammation and with a greater risk of postoperative hyphema.

"Cyclodiode". Trans-scleral diode laser cyclophotocoagulation in the treatment of advanced refractory glaucoma

PURPOSE

To analyze the results of intraocular pressure (IOP) reduction by diode laser contact cyclophotocoagulation ("cyclodiode") in cases of advanced glaucoma refractory to alternative treatments.

METHODS

Two hundred and ten eyes of 195 patients, ages 1 to 89 years (mean, 51 years) were followed for 3 to 30 months (mean, 10 months) after cyclodiode treatment.

RESULTS

More than one treatment was given in 102 eyes (49%), and the overall mean number of treatments given per eye was 1.75 (range, 2-5). Mean pretreatment IOP was 34.1 mmHg (+/-10.6 mmHg). At last follow-up, mean IOP was 20.1 mmHg (+/-9.3 mmHg), and mean total medications was reduced from 2.3 to 1.7. Mean final IOP was lowest in patients with silicone oil glaucoma (17.3 mmHg), and the mean reduction in IOP was greatest in patients with neovascular glaucoma (23.9 mmHg). At last follow-up, visual acuity was worse than before treatment in 29% of eyes, unchanged in 60%, and better in 11%. Overall success rate (IOP < 22 mmHg) was 66% at a mean follow-up of 10 months. Phthisis occurred in one eye (0.5%), and chronic hypotony (0 mmHg < IOP < 5 mmHg for > 3 months) in a further two eyes (1%). Corneal graft decompensation followed treatment in two eyes, macular pucker occurred in one eye, and combined hyphema/vitreous hemorrhage in one patient.

CONCLUSIONS

Diode laser cycloablation is relatively safe and effective at controlling IOP in eyes with advanced refractory glaucoma in the short and medium term. With the treatment parameters used, multiple applications may be needed.

[Pupilography in early diagnosis of primary open-angle glaucoma]

The pupil reactions in young subjects with emmetropic and myopic refraction, in normal subjects aged over 40, and in patients with primary open-angle glaucoma (POAG) are analyzed in relation to the trophic changes in the iris and functional activity of the ciliary muscle. These processes course in parallel with each other, but in POAG the changes in the pupil reaction are preceded by dystrophy of the iris and ciliary body, which is due to a slower conduction of pulses via the conduction routes. This permits the use of pupilography for early diagnosis of POAG.

The mechanism of intraocular pressure rise during cyclocryotherapy

PURPOSE

Intraocular pressure (IOP) spikes that occur during cyclocryotherapy for advanced glaucoma may further injure the already damaged glaucomatous optic nerve and be responsible for visual impairment that may occur after this treatment. The authors investigated the mechanism of pressure rise to see whether it can be avoided and thus prevent further optic nerve injury. The authors postulated that intraocular ice forms during the cryo procedure and causes the pressure changes.

METHODS

Intraocular pressure was monitored using a pneumatonometer during 15 cryocycles of four patients with advanced glaucoma and 21 cryocycles of five normal rabbits. A simple thermal model was developed to analyze the relation between volume expansion and pressure rise in the eye. The physical effect of freezing rabbit eye structures was investigated in vitro.

RESULTS

The largest pressure spikes observed during the cryocycles in this work were increases of 32 mm Hg for humans and 25 mm Hg for rabbits. The mean value of the IOP immediately before and after the cryo freezing stage was 53 +/- 1 and 68 +/- 2 mm Hg, respectively, for humans and 22 +/- 1 and 32 +/- 1 mm Hg for rabbits. The parameters of the thermal model were determined from the observed IOP spikes. Calculated thaw times were consistent with measured times for return to precryo IOPs. In vitro cryoapplication (rabbit eye) showed the formation of an ice ball internal to the eye.

CONCLUSIONS

Volumetric increase of the intraocular content related to the formation of an ice ball in the eye, is the mechanism of pressure spikes during cyclocryotherapy. Because this complication is unavoidable, other cyclodestuctive methods may be more prudent, particularly in patients with advanced glaucoma.

Serotonin-induced constriction of ocular arteries in atherosclerotic monkeys. Implications for ischemic disorders of the retina and optic nerve head

BACKGROUND

Ischemic disorders of the retina and optic nerve head, which constitute a common cause of visual loss, are usually seen in patients with atherosclerosis.

OBJECTIVE

To test the hypothesis that serotonin, which is released when platelets aggregate, may produce vasospasm in atherosclerotic monkeys and, thus, may contribute to the ischemic disorders and that short-term dietary treatment of atherosclerosis causes the propensity to vasospasm to subside.

METHODS

We studied the response of retinal and posterior ciliary circulation to serotonin in 18 atherosclerotic (25 eyes) and 5 normal (8 eyes) cynomolgus monkeys. The eyes were evaluated by color fundus photography and fluorescein fundus angiography. The eyes were examined under basal conditions and, at a different time, during the intravenous infusion of serotonin. In 6 of the 18 atherosclerotic animals, the evaluation was repeated 5 to 12 months after discontinuing the atherogenic diet (ie, the regression group).

RESULTS

Serotonin had no effect in normal monkeys. In 18 atherosclerotic monkeys, serotonin produced transient occlusion or delayed filling of the central retinal artery and/or posterior ciliary artery (PCA) in 9 eyes of 9 animals, involving the central retinal artery in 5, lateral PCA in 8, and medial PCA in 5, in various combinations. In 6 animals (6 eyes) of the regression group, the vasoconstrictor effect of serotonin was abolished completely, except in the medial PCA in 1 eye.

CONCLUSIONS

Serotonin, in the presence of atherosclerotic lesions, can cause transient, complete occlusion or impaired blood flow in the central retinal artery and/or PCA. We speculate that this mechanism may play a role in the development of ischemic disorders of the retina and optic nerve head. Discontinuing the atherogenic diet abolished or markedly improved the serotonin-induced vasoconstriction within a few months.