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.