Evaluation of blotchy pigments in the anterior chamber angle as a sign of angle closure

Background:

Blotchy pigments in the anterior chamber (AC) angle are considered diagnostic of primary angle closure (PAC). But there are no reports either on the prevalence of blotchy pigments in AC angles or the validity of this sign.

Aims:

To determine the prevalence of blotchy pigments in AC angles and to evaluate their relationship with glaucomatous optic neuropathy (GON) in eyes with occludable angles.

Setting and Design:

Cross-sectional, comparative study.

Materials and Methods:

Gonioscopy was performed in 1001 eyes of 526 subjects (245 eyes of 148 consecutive, occludable angle subjects and 756 eyes of 378 non-consecutive, open angle subjects), above 35 years of age. Quadrant-wise location of blotchy pigments was documented.

Statistical Analysis:

Odds of blotchy pigments in occludable angles against that in open angles were evaluated. Relationship of GON with blotchy pigments in occludable angle eyes was evaluated using a multivariate model.

Results:

Prevalence of blotchy pigments in occludable angles was 28.6% (95% CI, 22.9-34.3) and in open angles was 4.7% (95% CI, 3.2-6.3). Blotchy pigments were more frequently seen in inferior (16%) and superior quadrants (15%) of occludable angles, and inferior quadrant of open angles (4%). Odds of superior quadrant blotchy pigments in occludable angles were 33 times that in open angles. GON was seen in 107 occludable angle eyes. Blotchy pigments were not significantly associated with GON (odds ratio = 0.5; P = 0.1).

Conclusions:

Blotchy pigments were seen in 28.6% of occludable angle eyes and 4.7% of open angles eyes. Presence of blotchy pigments in the superior quadrant is more common in occludable angles. Presence of GON in occludable angle eyes was not associated with blotchy pigments.     

Effects of Argon Laser Iridotomy on the Corneal Endothelium of Pigmented Rabbit Eyes

Purpose

In Asian countries, laser iridotomy for the treatment of angle-closure glaucoma is a common cause of bullous keratopathy, which may be associated with a shallow anterior chamber and dark iris pigmentation in Asians. Several cases of corneal decompensation after argon laser iridotomy have been reported. In the present study, we evaluated the harmful effects of argon laser iridotomy on the corneal endothelium.

Methods

Argon laser iridotomy was performed on the right eyes of pigmented rabbits. Changes in corneal thickness and endothelial cell density after laser iridotomy were evaluated. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) was performed for assessment of corneal endothelial cell apoptosis. Combined staining with alizarin red and trypan blue, as well as a live/dead cell assay, were performed for evaluation of damage to the corneal endothelium induced by laser iridotomy.

Results

Corneal thickness did not change immediately after laser iridotomy; however, a significant increase was observed 24 hours after iridotomy (p = 0.001). The endothelial cell density of laser-treated eyes four days after laser iridotomy was significantly decreased compared with control eyes (p < 0.001). TUNEL staining showed many TUNEL-positive cells in the corneal endothelium and corneal stroma. No endothelial trypan blue-stained cell nuclei were observed after laser iridotomy; however, several large endothelial cells with damaged membrane integrity were observed. The live/dead cell assay clearly showed a large number of dead cells stained red in several areas throughout the entire corneal button 24 hours after iridotomy.

Conclusions

Argon laser iridotomy induces corneal endothelial cell apoptosis in pigmented rabbit eyes, resulting in decreased endothelial cell density.     

Cyclodiode laser in the treatment of acute angle closure

Aim

To describe the outcome of using diode laser transscleral cyclophotocoagulation (cyclodiode laser) as a safe technique in managing acute angle closure refractory to conventional treatment.

Methods

This is a retrospective case series from two ophthalmic units in the United Kingdom. Five patients with acute angle closure refractory to medical and laser treatment underwent cyclodiode laser treatment. Demographic information, symptoms, medical and surgical treatment, visual outcomes, and intraocular pressure (IOP) control were recorded.

Case reports

All five patients had symptomatic acute angle closure. Conventional management, including topical and systemic medical treatment, laser iridotomy and laser iridoplasty, did not achieve adequate IOP control or relieve symptoms. Emergency cyclodiode laser treatment was performed within 2–23 days of presentation. All patients subsequently required lensectomy at a later date. At final follow-up (6–14 months), all patients had visual acuity of 6/12 or better with well-controlled IOPs (≤17 mm Hg). Only one patient was on topical treatment. One patient developed a persistent low-grade anterior uveitis.

Discussion

Cyclodiode laser is a safe alternative to emergency lensectomy or trabeculectomy in cases of acute angle closure, which do not respond to treatment.     

Laser peripheral iridotomy with iridoplasty in primary angle closure suspect: anterior chamber analysis by pentacam

Purpose

To compare conventional laser peripheral iridotomy (LPI) and LPI combined with laser peripheral iridoplasty in eyes with primary angle closure suspect (PACS) by assessment of anterior chamber dimensional changes using a Pentacam.

Methods

Forty-eight eyes of 24 subjects with bilateral PACS were recruited consecutively. Each eye was randomly allocated to treatment with conventional LPI, argon LPI only, or LPI plus iridoplasty, which consisted of simultaneous argon LPI and peripheral iridoplasty. Anterior chamber measurements were performed on each eye using a Pentacam, both before and after treatment. Mean anterior chamber depth (ACD), anterior chamber volume (ACV), and anterior chamber angle were measured, and topographic ACD analysis was performed. Results were compared between the two treatment groups.

Results

After treatment with either conventional LPI or LPI plus iridoplasty, the mean ACD and ACV increased significantly. Topographic ACD analysis revealed that the mid-to-peripheral ACD increase was significantly greater in the LPI plus iridoplasty group than in eyes treated with conventional LPI. Intraocular pressure changes and post-LPI complications did not differ between the groups.

Conclusions

Compared with conventional LPI, our study showed that LPI plus iridoplasty improved the mid-to-peripheral ACD increase. This procedure may have a role as an adjunct for reducing angle closure by simultaneously eliminating pupillary and non-pupillary block components.     

Prognostic Factors for the Success of Laser Iridotomy for Acute Primary Angle Closure Glaucoma

Purpose

To identify the prognostic factors for successful laser iridotomy for acute angle-closure glaucoma (AACG).

Methods

We retrospectively reviewed the medical records of 77 eyes of 77 patients with AACG with initial intraocular pressure (IOP) above 40 mmHg. All of the patients received maximum tolerable medical therapy (MTMT) followed by laser iridotomy. In order to comparatively analyze the factors affecting successful laser iridotomy, an increase in IOP on follow-up was defined as increase in IOP greater than 21 mmHg requiring medical or surgical treatment.

Results

Successful laser iridotomy was achieved in 59.7% (46/77 eyes). Thirty-one eyes (40.3%) exhibited increased IOP on follow-up, and of these, 30 eyes developed an increase in IOP within six months after the first attack. The success rate was higher (92.9%) in 42 patients who had greater than 30% IOP reduction by MTMT at the first attack compared to the 35 patients whose IOP reduction was less than 30%, of which 24 eyes (72.7%) showed more than 30% IOP reduction after intravenous hyperosmotic agent treatment (p=0.012). The success rate was higher in patients treated within seven days after the development of symptoms than in those treated after seven days (Odds ratio, 4.51; 95% confidence interval, 1.38 to 14.75).

Conclusions

Our data suggest that we can expect successful IOP control after laser iridotomy in eyes with AACG if the patient can be treated within seven days after the development of symptoms and if the IOP reduction was more than 30% by MTMT.     

Anterior segment morphology after laser iridotomy in primary angle closure suspects

Purpose

To evaluate and compare the changes in anterior segment parameters in primary angle closure suspects before and after laser peripheral iridotomy and intrasession repeatability of measurements before laser iridotomy as assessed by Scheimpflug‐Placido disc topographer.

Methods

Before laser iridotomy, 56 eyes of 56 primary angle closure suspect patients underwent anterior segment analysis with the Sirius Scheimpflug‐Placido disc topographer system using glaucoma analysis mode, which was repeated a week after iridotomy. Anterior segment parameters such as central anterior chamber depth, central corneal thickness, anterior chamber volume and iridocorneal angle were analysed before and after laser iridotomy and compared with paired t‐test. Three consecutive scans were obtained to assess the intrasession repeatability of measurements before iridotomy by a single examiner and intraclass correlation co‐efficient was calculated. Multivariate regression analysis was performed to evaluate the predictors associated with iridocorneal angle narrowing.

Results

Intraclass correlation co‐efficient values ranged from 0.982 for anterior chamber volume to 0.998 for the iridocorneal angle. After laser iridotomy, mean central anterior chamber depth increased from 2.14 ± 0.29 mm to 2.21 ± 0.28 mm (p = 0.04), mean anterior chamber volume increased from 96.2 ± 16.98 mm³ to 98.14 ± 15.87 mm³ (p < 0.0001) and mean iridocorneal angle widened from 33.38 ± 3.96° to 34.82 ± 4.27° (p = 0.01), compared with pre‐iridotomy status. There was no change in central corneal thickness, intraocular pressure or pupil diameter. Multivariate regression analysis model showed that at one week after iridotomy, iridocorneal angle opening was positively correlated with age (β = 0.773, p = 0.005) and anterior chamber volume (β = 1.308, p < 0.0001).

Conclusions

Laser peripheral iridotomy induces significant changes in the 3‐D anterior segment morphology in primary angle closure suspect patients. The Scheimpflug‐Placido disc topographer provides reproducible measurements of the iridocorneal angle and other parameters measured and hence, may become clinically useful for non‐invasive detection of potentially occludable angles. Predictors of iridocorneal angle widening after iridotomy were older age and anterior chamber volume.

     

YAG laser iridotomy treatment for primary angle closure in east Asian eyes

AIM: To assess the efficacy of Nd:YAG laser iridotomy as initial treatment for primary angle closure in a community setting in rural Mongolia. METHODS: Subjects with occludable drainage angles in two glaucoma prevalence surveys in Mongolia (carried out in 1995 and 1997) were treated with YAG laser iridotomy at the time of diagnosis. These patients were re-examined in 1998. Patency of iridotomy, intraocular pressure (IOP), visual acuity, and gonioscopic findings were recorded. Iridotomy was classified unsuccessful in eyes where further surgical intervention was required or in which there was a loss of visual acuity to <3/60 from glaucomatous optic neuropathy. RESULTS: 164 eyes of 98 subjects were examined. Patent peripheral iridotomies were found in 98.1% (157/160) of eyes that had not undergone surgery. Median angle width increased by two Shaffer grades following iridotomy. Iridotomy alone failed in 3% eyes with narrow drainage angles and either peripheral anterior synechiae or raised IOP, but normal optic discs and visual fields. However, in eyes with established glaucomatous optic neuropathy at diagnosis iridotomy failed in 47%. None of the eyes with occludable angles that were normal in all other respects, and underwent iridotomy, developed glaucomatous optic neuropathy or symptomatic angle closure within the follow up period. CONCLUSIONS: Nd: YAG laser iridotomy is effective in widening the drainage angle and reducing elevated IOP in east Asian people with primary angle closure. This suggests that pupil block is a significant mechanism causing closure of the angle in this population. Once glaucomatous optic neuropathy associated with synechial angle closure has occurred, iridotomy alone is less effective at controlling IOP.     

Prevalence of plateau iris configuration in primary angle closure glaucoma using ultrasound biomicroscopy in the Indian population

Purpose:

To report the prevalence of plateau iris in patients with primary angle closure glaucoma (PACG), in North India.

Materials and Methods:

The patients with PACG, attending the glaucoma services at a tertiary care center in North India were included in the study. All patients had undergone Nd-YAG laser peripheral iridotomy at least four weeks prior to inclusion in the study. Four weeks prior to inclusion in the study, none of the patients had used pilocarpine. Ultrasound Biomicroscopy (UBM) images were qualitatively evaluated and plateau iris configuration was defined in an eye if the following criteria were fulfilled in two or more quadrants: anteriorly directed ciliary process supporting the peripheral iris, steep rise of iris root from its point of insertion followed by a downward angulation from the corneoscleral wall, absent ciliary sulcus, and iridotrabecular contact in the same quadrant.

Results:

One hundred and one eyes were included in the study. There were 63 (62.4%) females and 38 (37.6%) males. The mean age of the patients was 57.8 ± 9.5 years (range: 42 to 78 years). The mean axial length in the study population was 22.2 ± 1.1 mm. The mean spherical equivalent refraction was 0.06 ± 1.12 D. The mean intraocular pressure was 18.5 ± 4.7 mmHg (range: 12 – 24 mmHg). Twenty-nine (28.7%) subjects were diagnosed with plateau iris on the basis of above-defined criteria. Of the 29 eyes, 18 (62.1%) subjects had plateau iris in two quadrants, nine (31.03%) in three quadrants, and two (6.8%) had this configuration in all the four quadrants.

Conclusions:

Approximately 30% of the eyes with PACG had plateau iris on UBM. Plateau iris was very often the cause for residual angle closure following laser peripheral iridotomy in Indian eyes with PACG.     

Contribution of the argon laser in iridotomy using the Yag laser

Yag laser iridotomy was performed immediately after argon laser application in 59 eyes with chronic angle closure glaucoma, occludable angle and secondary glaucoma. Postoperative intraocular pressure was elevated temporarily more than 5 mmHg on 86.4% of patients. Iris haemorrhages occurred in 17% of cases when laser Yag iridotomy was carried out with a power of 4 to 6 mJ. Prior argon laser seemed to prevent iris haemorrhages.     

Posterior Hyaloidotomy by Nd:YAG Laser Application in a Patient with Postpartum Depression Caused by Valsalva Retinopathy

Purpose

The aim of this report is to present a case of premacular hemorrhage in a 37-week pregnant woman with concurrent presence of postpartum depression secondary to her ocular disease.

Methods

A 27-year-old woman in her 37th week of pregnancy presented with Valsalva retinopathy, which occurred in her left eye secondary to severe coughing. Her visual acuity was reduced to perception of hand motions, and she was agitated because of the loss of vision. The patient, who gave birth by cesarean section, was admitted for control examination 2 weeks after birth. No change was observed in premacular hemorrhage in control examination. However, the patient''s relatives stated that the patient was very agitated and disinterested in her baby. For this reason, the patient was referred to the psychiatry clinic, and she was diagnosed with postpartum depression. The anatomical location of the premacular hemorrhage was determined by spectral domain optical coherence tomography.

Results

Neodymium yttrium aluminum garnet (Nd:YAG) laser hyaloidotomy was performed to her left eye on the same day. Rapid release of premacular hemorrhage into the vitreous cavity was observed immediately after Nd:YAG laser application. Two days after the application, the patient''s visual acuity had improved to 20/20. The clinical improvement positively impacted on the patient''s mood.

Conclusion

In pregnant patients suffering from Valsalva retinopathy during the postpartum period, posterior hyaloidotomy by Nd:YAG laser can be implemented in terms of the patients’ own and their babies’ physical and mental health.Key words: Nd:YAG laser, Postpartum depression, Pregnancy, Valsalva retinopathy     

Nd:YAG membranotomy for preretinal hemorrhage secondary to valsalva retinopathy

Purpose

To report four cases of premacular hemorrhage secondary to valsalva retinopathy treated with Nd:YAG membranotomy and discuss techniques as well as the literature.

Design

Retrospective case series.

Methods

A retrospective review was conducted for four patients with vision obstructing hemorrhage secondary to valsalva retinopathy. These patients were all treated with Nd:YAG membranotomy.

Results

Four patients with premacular hemorrhage secondary to valsalva retinopathy were treated with Nd:YAG laser creating a membranotomy to drain the hemorrhage. Power settings ranged from 1.7 to 3.8 mJ. Visual acuity at presentation ranged from 20/400 (1 patient) to count fingers (3 patients). Visual acuity improved in three out of four patients after laser treatment. Final visual acuity ranged from 20/20 to 20/30 in these three patients. One patient was lost to follow up after performing laser membranotomy and therefore visual acuity after treatment was not obtained. No complications were noted.

Conclusion

Nd:YAG membranotomy is a non-invasive, office-based treatment option that may be successfully used to treat premacular hemorrhage secondary to valsalva retinopathy.     

Endotamponades in pars plana vitrectomy for metallic intraocular foreign body associated with endophthalmitis

AIM: To study the criterion-reference of endotamponades in pars plana vitrectomy for metallic intraocular foreign body (MIOFD) associated with endophthalmitis. METHODS: Thirty-six patients of MIOFD with endophthalmitis accorded with exclusion and inclusion criteria were retrospectively analyzed. A detailed analysis of the patients’ natural factors, preoperative examinations, intraoperative endotamponades choice, postoperative complications and therapeutic effects was performed. RESULTS: BSS was used in 4 eyes without obvious retinal damage. There was no postoperative complication and the visual acuity (VA) was improved. Sixteen eyes that had mild retinal damage filled with C3F8 gas. The postoperative VA improved in 10 eyes (62.5%), 4 eyes (25.0%) remained unchanged and 2 eyes (12.5%) decreased. Only 2 cases occurred postoperative retinal detachment in gas group. Another 16 eyes with serious retinal damage were treated with silicone oil. Postoperative VA of 9 eyes (56.3%) improved, 3 eyes (18.8%) remained unchanged and 4 eyes (25.0%) decreased. The silicone oil group had higher incidence of postoperative complications, but the incidence of secondary treatment had no significant different between silicone oil and gas group. CONCLUSION: An appropriate choice of endotamponades in vitrectomy surgery for MIOFB with endophthalmitis is important for prognosis.     

Changes in Spherical Aberration after Various Corneal Surface Ablation Techniques

Purpose

The corneal change induced by refractive procedures influence both the postoperative refractive status and the ocular spherical aberration (SA). We evaluated changes in corneal SA after three types of surface ablation: phototherapeutic keratectomy (PTK), myopic photorefractive keratectomy (PRK), and myopic wavefront-guided laser epithelial keratomileusis (LASEK).

Methods

Twenty-six eyes (25 patients) were subjected to PTK 26 eyes (14 patients) to PRK, and 34 eyes (17 patients) to wavefront-guided LASEK. Corneal SA was measured with the iTrace in all patients both preoperatively and 6 months postoperatively.

Results

Six months after surgery, mean corneal SA was -0.173 ± 0.171 µm in the PTK group, 0.672 ± 0.200 µm in the PRK group, and 0.143 ± 0.136 µm in the wavefront-guided LASEK group. The mean difference between the preoperative and postoperative corneal SA (ΔSA) was -0.475 µm in the PTK group, 0.402 µm in the PRK group, and -0.143 µm in the wavefront-guided LASEK group.

Conclusions

Surgically induced changes in corneal SA vary with procedure. The prediction of the pattern of SA change induced by various surface ablation procedures may be helpful for developing future surgical procedures.     

Argon laser versus erbium:YAG laser in the treatment of xanthelasma palpebrarum

Background

Xanthelasma palpebrarum is the most common of the xanthomas with asymptomatic, symmetrical, bilateral, soft, yellow, polygonal papules around the eyelids. Though it is a benign lesion causing no functional disturbance, it is esthetically annoying. The surgical laser offers an extremely elegant and powerful solution to this problem.

Objective

To evaluate the effectiveness of erbium:YAG and argon lasers in the treatment of xanthelasma lesions.

Patients and methods

Forty patients were included in the study. Twenty patients (15 patients were bilateral with 30 eyes either in the upper or lower lid and 5 patients were unilateral) were treated with erbium:YAG laser. Another 20 patients (10 patients were bilateral with 20 eyes and 10 patients were unilateral) were treated with argon laser.

Results

In the majority of treated patients (either treated with erbium:YAG or argon laser), xanthelasma lesions were completely disappeared or significantly decreased in size. Two patients showed pigmentary changes in the form of hypopigmentation with erbium:YAG laser (one case), another case showed hyperpigmentation. No intraoperative complication was observed. No significant scar or recurrence was observed.

Conclusion

Argon laser in xanthelasma is an easy, effective, and safe method of treatment for small lesions and YAG laser is more better for large lesions than argon laser.     

Standardization of choroidal thickness measurements using enhanced depth imaging optical coherence tomography

AIM:To describe and evaluate a standardized protocol for measuring the choroidal thickness (ChT) using enhanced depth imaging optical coherence tomography (EDI OCT).METHODS:Single 9 mm EDI OCT line scans across the fovea were used for this study. The protocol used in this study classified the EDI OCT images into four groups based on the appearance of the choroidal-scleral interface and suprachoroidal space. Two evaluation iterations of experiments were performed:first, the protocol was validated in a pilot study of 12 healthy eyes. Afterwards, the applicability of the protocol was tested in 82 eyes of patients with diabetes. Inter-observer and intra-observer agreements on image classifications were performed using Cohen’s kappa coefficient (k). Intraclass correlation coefficient (ICC) and Bland-Altman’s methodology were used for the measurement of the ChT.RESULTS:There was a moderate (k=0.42) and perfect (k=1) inter- and intra-observer agreements on image classifications from healthy eyes images and substantial (k=0.66) and almost perfect (k=0.86) agreements from diabetic eyes images. The proposed protocol showed excellent inter- and intra-observer agreements for the ChT measurements on both, healthy eyes and diabetic eyes (ICC>0.90 in all image categories). The Bland-Altman plot showed a relatively large ChT measurement agreement in the scans that contained less visible choroidal outer boundary.CONCLUSIONS:A protocol to standardize ChT measurements in EDI OCT images has been developed; the results obtained using this protocol show that the technique is accurate and reliable for routine clinical practice and research.     

Rac1 activates HIF-1 in laser induced choroidal neovascularization

AIM: To study the effect of Rac1 on the induction of HIF-1α in choroidal neovascularization (CNV) in mice. METHODS: One hundred C57BL/6J mice were laser photocoagulated to induce CNV, fifty mice of that were selected randomly for intravitreal injection of Rac1 inhibitor NSC23766 solution (1μL). After laser photocoagulation, fundus fluorescein angiography (FFA) was performed to verify the growth of CNV, Immunohistochemistry and Western blot were used to detect HIF-1α and Rac1 in posterior segment of eye globes. RESULTS: FFA verified that incidence of CNV was significantly reduced in the eyes with NSC23766 injection comparing with that of eyes without NSC23766 injection (P<0.01). Immunohistochemistry detected that HIF-1α and Rac1 mainly expressing in the new fibrovascular tissue. Western blot showed that HIF-1α and Rac1 was highly increased in tissue explants of retinal pigment epithelium （RPE） and choroid without NSC23766 injection. But for tissue explants of RPE and choroid with NSC23766 injection, both the expression of HIF-1α and Rac1 were inhibited. CONCLUSION: Rac1 is crucial to activate HIF-1 regulating the growth of CNV, and its inhibition may have potential therapeutic value.     

Incidence,efficacy and safety of YAG laser goniopuncture following nonpenetrating deep sclerectomy at a university hospital in Riyadh,Saudi Arabia

Purpose

Assessing the frequency and evaluating the efficacy and safety of Neodymium:Yttrium Aluminum Garnet (Nd:YAG) Laser goniopuncture (LGP) following nonpenetrating deep sclerectomy (NPDS).

Design

Retrospective cohort study.

Patients and methods

We retrospectively reviewed the outcome of 197 eyes of 153 patients with open angle glaucoma who underwent either NPDS or NPDS combined with cataract extraction between January 2005 and September 2010 at King Abdulaziz University Hospital (KAUH). Both demographic and clinical data were retrieved and analysed.

Results

Goniopuncture (GP) was needed in 48 (24.4%) of the eyes which had NPDS or NPDS with cataract extraction after a mean post operative interval of 9.78 (±11.16) months. The mean IOP had significantly decreased from 23.3 (±5.9) mmHg prior to Nd:YAG LGP procedure to 14.6 (±4.4) mmHg at the last post-procedure assessment. At the last follow-up; Nd:YAG LGP was successful in controlling IOP in 27 eyes (56.3%). Mean Nd:YAG LGP failure time was 6.04 (±5.80) months. Young age (<50 years) (p = 0.001); type of glaucoma (secondary versus primary open angle, p = 0.0258) and the use of drainage implant (p = 0.038) were the identified predicting factors for the need of Nd:YAG LGP. Complications following Nd:YAG LGP occurred in 5 eyes (iris touch to TDM (4.2%), Hyphema (2.1%), hypotony maculopathy (2.1%) and choroidal detachment (2.1%).

Conclusions

LGP is an efficient IOP lowering procedure after NPDS, when it is indicated. It is a simple and noninvasive procedure. However, certain precautions should be taken to avoid complications.     

Interference of Descemet's Membrane with Aqueous Humor Drainage via an ExPRESS Mini Shunt

Purpose

To describe a case in which Descemet''s membrane interfered with aqueous humor drainage through an ExPRESS mini shunt. This problem was successfully solved by Nd:YAG laser membranotomy.

Case Report

A 70-year-old male, diagnosed with corticosteroid-induced glaucoma in his right eye, presented to our hospital. Topical betamethasone treatment was discontinued, and the patient was treated with intravenous D-mannitol and acetazolamide, followed by oral acetazolamide, oral potassium L-aspartate, topical dorzolamide hydrochloride, topical carteolol hydrochloride, and topical latanoprost. However, his right intraocular pressure (IOP) remained elevated. We performed ExPRESS shunt surgery in the patient''s right eye. His postoperative IOP was initially within the normal range, but it reincreased 1 month after surgery. We found that the Descemet''s membrane was interfering with both the primary (axial) and reserve orifices at the tip of the ExPRESS mini shunt. Nd:YAG laser membranotomy was performed and the patient''s IOP again improved without any other medical treatment.

Conclusion

Descemet''s membrane interfered with aqueous humor drainage via ExPRESS mini shunt, causing an increased IOP, which was resolved by Nd:YAG laser membranotomy.Key words: Corticosteroid-induced glaucoma, Descemet''s membrane, ExPRESS mini shunt     

A histological study of rabbit corneas after transepithelial corneal crosslinking using partial epithelial photoablation or ethanol treatment

AIM: To evaluate the histological changes after transepithelial corneal crosslinking (CXL) using partial thickness excimer laser ablation or epithelial ethanol application in an experimental rabbit study.METHODS: Right eyes of twenty-four rabbits were studied. Four eyes received total epithelial debridement (group I). Four eyes received partial thickness epithelial ablation with excimer laser (group II). Twelve eyes were treated with different durations (30s and 60s) and concentrations (18% to 48%) of ethanol (group III). Riboflavin was applied for 30min intervals along with topical proparacaine drops with benzalkonium chloride, and 370 nm irradiation was performed for 30min, while riboflavin was instilled every 3min. Four eyes (group IV) received 48% ethanol for 30s without riboflavin and irradiation. Eyes were collected after 24h and examined histologically.RESULTS: All eyes in group I showed keratocyte loss in the superficial 300 μ of corneal storma. In group II, 1-4 layers of epithelium were preserved and no keratocyte loss occurred. In group III, CXL after treatment with ethanol up to 24% concentration and up to 60s revealed no keratocyte loss. CXL after treatment with 48% and higher ethanol concentrations yielded keratocyte loss in the superficial 200 μ to 300 μ of cornea.CONCLUSION: Incomplete excimer laser ablation of the epithelium or treatment with ethanol up to 24% concentration and up to 60s duration yielded no stromal keratocyte loss. To get the same histological appearance seen in epithelial debridement group, partial thickness excimer laser epithelial ablation or ethanol application is not adequate for transepithelial CXL.