Occludable Angles Research Articles

Clinical Outcomes After Lens Extraction for Visually Significant Cataract in Eyes With Primary Angle Closure

To examine the clinical outcomes of cataract extraction in eyes with primary angle closure (PAC) and coexisting cataract. Retrospective study of surgical outcomes after phacoemulsification and intraocular lens implantation in 55 eyes of 39 patients with PAC or occludable angles and visually symptomatic cataract. Approximately, 61.8% of eyes had received a peripheral iridotomy and 65% had evidence of glaucomatous optic neuropathy (GON). At 7.2 months after cataract extraction, a statistically significant reduction in intraocular pressure (IOP) was observed in all eyes with PAC (median 3 mm Hg, P=<0.0001). The reduction in IOP was significantly greater in eyes with a higher preoperative IOP (P=<0.0001). On average, one less glaucoma medication was in use postoperatively (P=0.01). Eyes with >180 degrees of peripheral anterior synechiae (PAS) preoperatively achieved a significantly greater reduction in IOP postoperatively compared with those with less PAS (7.5 vs. 4.4 mm Hg, P=0.03). The observed reduction in IOP in eyes with PAC and GON was significantly greater compared with those without GON (5.6 vs. 2.5 mm Hg, P=0.01). Visual acuity was significantly improved after cataract extraction by a mean of -0.23 LogMAR units (P=0.0001). Contrary to earlier expectations, the observed reduction in postoperative IOP in eyes with PAC was significantly greater in the presence of a higher preoperative IOP, a larger number of glaucoma medication, narrower iridotrabecular angle width, and greater extent of PAS formation and in eyes with evidence of GON. Lens extraction seems to have a beneficial effect on IOP control in PAC, and is especially efficacious in more advanced cases.

Pentacam sensitivity and specificity in detecting occludable angles

To assess the sensitivity and specificity of Pentacam measurements in detection of occludable angles and to provide cutoff values. Observational, single-center, cross-sectional study on 64 Caucasian eyes: 28 (43.7%) primary narrow angles or primary angle-closure glaucoma, and 36 (56.2%) controls: all subjects were evaluated and classified by gonioscopy (Shaffer classification). The following measurements have been considered: superior and inferior anterior chamber angle (ACA), temporal and nasal ACA, anterior chamber depth (ACD) using 5 value representation (central, superior, inferior, nasal, temporal), and anterior chamber volume (ACV). Validity of Pentacam parameters to detect patients in Shaffer 0 or I class was assessed by receiver operating characteristic (ROC) curves analysis; cutoffs were chosen as to maximize sensitivity and specificity. All the considered Pentacam measures were statistically different between the 2 groups (p<0.0001). All Shaffer grade groups differed in all parameters (p<0.001), except for grade 0 and I, which did not differ in any. Area under the curve ROC analysis revealed high discriminant power of all Pentacam measures: ACA = 0.94; ACD = 0.91; ACD central = 0.89; and ACV = 0.89. Chosen cutoff values (ACA = 22.4°; ACD = 1.12 mm; ACD central = 1.93 mm; ACV = 84 mm3) allowed correct classification of narrow angles. The study pointed out a high power of Pentacam AVA, ACV, and ACD in detecting occludable angles. Pentacam is simple to use, reliable, and noncontact, provides parameters in a short period, and represents a possible screening tool.

Correlation Between Extent of Preexisting Organic Angle Closure and Long-term Outcome After Laser Peripheral Iridotomy in Eyes With Primary Angle Closure

To investigate the long-term clinical course of eyes with primary angle closure (PAC) after laser peripheral iridotomy (LPI), and to determine whether there is a significant correlation between the extent of a pre-existing peripheral anterior synechiae (PAS) and the intraocular pressure (IOP). We retrospectively examined the course of 107 consecutive eyes with occludable angles after LPI. An organic angle closure was identified by indentation gonioscopy. The eyes were assigned into 3 groups: primary angle-closure suspect (PACS), PAC with PAS below 2 quadrants (PAC1), and PAC with PAS more than 2 quadrants (PAC2). At the initial diagnosis, the mean age was 64.8±8.4, and the mean IOP was 15.7±3.8 mm Hg. There was a significant correlation between the maximum IOP before the LPI and the extent of the PAS (P=0.0002; Spearman rank correlation). After LPI, the success rate, that is, an IOP less than 20 mm Hg with medications at 2 consecutive visits, in the PACS group was 100% during a 10-year follow-up. The success rate was 89.8%±3.7% and 62.7%±16.6% in eyes with PAC1 and eyes with PAC2, respectively (P=0.0767, PAC2 versus PAC1; log-rank test). The majority of chronic PAC, at least, eyes with less extensive PAS, maintained good IOP control with and without antiglaucoma drugs, and the extent of preexisting organic angle closure was one of the predictive prognostic factors.

Prevalence of Primary Angle Closure and Primary Angle-Closure Glaucoma in a Southwestern Rural Population of Japan: The Kumejima Study

To determine the prevalence and ocular biometry of primary angle closure (PAC) and primary angle-closure glaucoma (PACG) in a rural population in southwestern Japan. Population-based cross-sectional study. All residents aged 40 years or older in Kumejima, Okinawa, Japan. Of the 4632 residents 40 years of age or older, 3762 (participation rate, 81.2%) underwent a detailed ocular examination, including measurement of the best-corrected visual acuity, slit-lamp examination, Goldmann applanation tonometry, static and dynamic gonioscopy, undilated stereoscopic optic fundus photographs, autorefractometry, partial coherence laser interferometry, noncontact specular microscopy, and screening visual field (VF) testing using frequency-doubling technology. If glaucoma or related or other ocular disorders were suspected, the subject was referred for a definitive examination including VF testing with the 24-2 Swedish Interactive Thresholding Algorithm Standard program of the Humphrey Field Analyzer (Carl Zeiss Meditec, Dublin, CA). Prevalence rates of primary angle-closure suspects (PACS), PAC, PACG, and PACG suspects. Under the standard definitions of the International Society of Geographical and Epidemiological Ophthalmology, the prevalence rates of PACS, PAC, and PACG were 8.8%, 3.7%, and 2.0%. Extending the diagnosis of PAC and PACG to include people with narrow but open angles and primary peripheral anterior synechiae, the prevalence rates of PAC and PACG increased to 6.0% and 2.2%, respectively. Hence, broadening the diagnostic categories in PAC and PACG increased the prevalence rates by 62% and 10%. Twenty-three subjects (0.6%; 95% confidence interval, 0.4%-0.9%) had a history of or were diagnosed with acute PAC. Older age, female gender, hyperopic refractive error, short axial length, and shallow anterior chamber depth were independent predictors of an occludable angle. The prevalence of PACG in Kumejima (2.2%) was one of the highest reported in population-based studies, that is, 3.7 times higher than in the Tajimi Study carried out in an urban center located in the central area of the main island of Japan. The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Diurnal Curve after Phacoemulsification in Patients with Pseudoexfoliation Syndrome and Cataract

Purpose: To evaluate the effect of phacoemulsification on the diurnal curve in patients with pseudoexfoliation syndrome.Method: 2052 patients aged 40 years and older attending our OPD services were screened, of whom 62 patients with pseudoexfoliation and associated significant cataract were selected for the study. All underwent a detailed examination including slit lamp examination, IOP, gonioscopy, and fundus examination. Diurnal variation of intraocular pressure was done at baseline and two and four weeks after phacoemulsification with IOL implantation. The IOP differences after surgery were compared and analyzed.Results: All 62 patients underwent successful phacoemulsification with IOL implantation. Anterior chamber IOL was implanted in 2 of the 6 cases with vitreous loss. The peak IOP of the diurnal curve reduced from 26 ± 3.2 mmHg pre surgery to 19 ± 1.2 mmHg, p < 0.01, while the mean baseline IOP reduced from 22 ± 5.3 mmHg to 15 ± 2.1 mmHg at 2 months after cataract extraction, p = 0.02. The IOP fluctuations (max-min IOP difference) in the diurnal curve also flattened significantly post-surgery in eyes with both open and occludable angles, p < 0.01, with the maximum difference observed during the later part of the day in both groups.Conclusions: Early cataract extraction with IOL can smooth out intraocular pressure fluctuations in patients with pseudoexfoliation and associated cataract with open or narrow angles.

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.

Anterior chamber angle evaluation with fourier-domain optical coherence tomography.

New advances in anterior segment optical coherence tomography (OCT) technology development allow visualizing the anterior chamber angle of the eye with high speed and high resolution. Fourier-domain (FD) OCT instruments working at 840 nm can reliably identify fine angle structures such as the Schwalbe's line. This paper demonstrates quantitative angle assessment with 840 nm FD-OCT and provides diagnostic cutoff values for occludable angle detection. This is useful for angle closure glaucoma diagnosis and management. Moreover, 840 nm FD-OCT is a useful tool for postsurgical evaluation in glaucoma patients.

Response to Dr Wishart (Non-steroidal drug-induced glaucoma)

Sir, We appreciate the thoughtful comments made by Dr Wishart1 and his interest in our review article.2 There is no way to compare non-medication-induced angle closure from other factors, nor are we suggesting that it is a more common event. The important issue is that physicians need to be aware of the potential of certain drugs to provoke an angle-closure attack in high-risk patients. Gonioscopy helps to identify high-risk patients, especially the hyperopic middle-aged or older patient, and would help physicians in advising their patients of the relative risk. Most cases of pharmacologically induced angle closure have reportedly been due to a pupillary block mechanism, with fewer cases being secondary to plateau iris configuration and choroidal effusions.3, 4 Therefore, a prophylactic laser peripheral iridotomy would be expected to be protective. The decision as to whether that would be appropriate given the risks of angle-closure glaucoma is weighed against the risks of the laser procedure. Dr Wishart noted the prevalence of a narrow angle in the Caucasian population to be relatively low. We suggest that it would be important to identify this population by gonioscopy so that appropriate counseling could be offered. The prevalence of narrow angles in other ethnic groups, especially Asians, is significantly higher.5 The reference for the statement ‘at least one third of acute closed angle glaucoma cases are related to over-the-counter or prescription drugs' was the third reference4 of our manuscript, but had been cited in error. The patients studied by Mapstone6 had experienced an acute attack in one of their eyes, and their contralateral eye that had had no sign of glaucoma or had been cases of intermittent angle-closure glaucoma underwent a tropicamide challenge test. In fact, not all the studied eyes had glaucoma but had occludable angle. The point that the risk of tropicamide causing angle closure is 0 is a curious comment, as this point certainly is not substantiated by any large trial in a large high-risk population. Provocative testing is known to be of limited predictive value. Although it is agreed that even in narrow angles dilation may not precipitate angle closure in every case, the obligation of physicians is to (1) recognize which patients may be at risk, (2) advise the patients of a potential risk with pharmacological dilation, and (3) offer a preventive treatment like prophylactic laser iridotomy with risks and benefits reviewed when deemed appropriate.

Ciliary body cysts in neurofibromatosis: A new coexistence?

Neurofibromatosis 1 (NF1) is an autosomal dominant, multisystem disorder that also effects the eye. Herein, we aimed to investigate the posterior iris surface and ciliary body morphology of NF1 patients by ultrasonic biomicroscopy (UB). Nine consecutive unrelated subjects with NF1, and as a control group 25 healthy subjects, were included in the study. All patients underwent ophthalmic examination including visual acuity testing, slit-lamp biomicroscopy, tonometry, gonioscopy (Schaffer classification), and dilated ophthalmoscopy, UB. Mean age was 35.1 ± 16.2 (range, 11-57) and 34.5 ± 15.6 (range, 9-60) for NF1 and control groups respectively (p>0.05). Lisch nodules were present in 16 of 18 eyes (88.8%) in NF1 group. Fundoscopic examination of the control group and 15 eyes of NF1 (83.3%) patients was normal, whereas hypoplastic and tilted optic nerve were present in three eyes, and temporally-located bone-spicule-like lesions was present in one eye of the NF1 group. UB revealed ciliary body cyst in 77.7% (14/18) of the eyes among NF1 group, and 8% (4/50) among control group (p<0.05). The mean size of the cysts were 520 ± 191 μ (range, 220-860 μ) and 495 ± 231 μ (range, 300-830 μ) at NF1 and control groups, respectively. Gonioscopic evaluation revealed that 55% of the NF1 patients have an unoccludable anterior chamber angle (Grade 3 or 4), 45% occludable angle (Grade 1 or 2), and 78% irregular pigment patches. However, occludable angle rate was just 4% in the control group, and none of the patients had irregular pigment patches. The coexistence of ciliary body cysts and NF1, and the effect of these cysts in the eye should be enlightened with further studies.

Randomised trial of sequential pretreatment for Nd:YAG laser iridotomy in dark irides

AimsTo compare iridotomy outcomes in dark irides by 1064 nm pulsed Nd:YAG laser with and without 532 nm continuous-wave Nd:YAG (frequency-doubled) green laser pretreatment.Methods30 patients with occludable anterior chamber angles...

Classification of primary angle closure disease

Primary angle closure disease, PACD, has had a plethora of classifications and terminologies. The International Society of Geographical and Epidemiological Ophthalmology (ISGEO) classification was a simple classification, extremely useful in surveys, but could not be clinically applied because of the varied presentation of PACD. Reviewing the literature, it was seen that the landmarks in progression of PACD were an anatomical predisposition; iridocorneal apposition/adhesions; chronic rise in intraocular pressure (IOP), despite an iridotomy; and glaucomatous optic neuropathy. Therefore, a staging system for PACD is proposed. PACD suspect--occludable angle; PACD I--occludable angle with evidence of closure, but a normal IOP after iridotomy; PACD II--peripheral anterior synechiae in an occludable angle with a chronically raised IOP after iridotomy, with or without a suspicious optic nerve head; and PACD III--peripheral anterior synechiae in an occludable angle, with a raised IOP after iridotomy, and glaucomatous optic neuropathy. This proposed classification has amalgamated all the clinically described subtypes of PACD--subacute, acute, chronic, symptomatic, and asymptomatic--into a staging, based on extent of damage to the outflow channels and optic nerve head, providing a basis for standardized therapy and possibly a quantifiable long-term prognosis.

Comparison of Axial Lengths in Occludable Angle and Angle-Closure Glaucoma—The Bhaktapur Glaucoma Study

To compare the anterior chamber depth (ACD) and axial length of eyes in a population-based sample among normal, occludable angle, and primary angle-closure glaucoma (PACG) groups. Totally, 3979 subjects from a population-based glaucoma prevalence study underwent complete ocular examination including four mirror gonioscopy. An angle in which >270 degrees of the posterior trabecular meshwork could not be seen was considered occludable. PACG was considered when there were features of primary angle closure (eye with an occludable angle, peripheral anterior synechiae, increased intraocular pressure, iris whorling, lens opacities, or excessive pigment deposition on the trabecular surface) and optic disc with glaucomatous damage. A handheld ultrasonic biometer was used to measure the ACD and the axial length of subjects. The ACD and axial length were measured on all subjects with occludable angles (n = 86), PACG (n = 17) and a random subgroup of normal subjects (n = 685). The measurements were compared among the groups and statistically analyzed using independent t-test, one-way analysis of variance, χ2 test, and logistic regression. The mean age among occludable angle and angle-closure glaucoma groups was 59.64 ± 9.70 and 71.23 ± 8.5 years, respectively, which was significantly higher (p < 0.001) than the mean of 54.03 ± 10.90 years among normal subjects. In the occludable angle group, the ACD (2.55 ± 0.69) was significantly different (p < 0.001) than the normal group (2.85 ± 0.39). The axial length (22.08 ± 0.83) in the occludable angle group was also considerably different (p < 0.001) when compared with the normal group (22.62 ± 0.90). In PACG group, the ACD and axial length were 2.48 ± 0.22 and 22.02 ± 0.59, respectively. The risk of having an occludable angle decreased with per unit millimeter increase in ACD (odds ratio, 0.24; 95% confidence intervals, 0.12-0.50) and axial length (odds ratio, 0.49; 95% confidence intervals, 0.36-0.67) after adjusting the effect of age and sex. The eyes in Nepalese population with occludable angle and angle-closure glaucoma appear to have significantly shallower anterior chambers and shorter axial lengths when compared with the normal group.

Retinal Vein Occlusion and Angle Closure

To describe a series of patients who have sustained a retinal vein occlusion (RVO) and also have primary angle-closure (PAC). We retrospectively ascertained demographic characteristics (age, sex, and ethnicity), presentation (history and examination findings), investigations undertaken, features of angle-closure or occludable angles (symptoms, method of diagnosis, and treatment), and outcome (intraocular pressure (IOP) and visual acuity). Nineteen subjects were included in the study, comprising 9 males and 10 females, with an average age of 69 years (range 44 to 86 y). The ethnicity of the group was diverse. The mode of presentation in 75% of patients was that RVO and PAC were diagnosed at the same clinical visit. In the remaining 25% of cases, the diagnosis of PAC was delayed and ranged from 4 months to 9 years after the RVO. Increased IOP on dilation was found to have raised the suspicion of PAC in some patients, either at the time of first presentation with RVO or at a later date during follow-up for the RVO, leading to gonioscopy and a diagnosis of PAC. In 1 patient, an observed asymmetrical cup-to-disc ratio led to gonioscopy and diagnosis of PAC. Fourteen patients sustained a central retinal vein occlusion (CRVO), 2 subjects sustained a hemicentral retinal vein occlusion (HRVO), and 3 patients had a branch retinal vein occlusion. In the vast majority of cases in this series (18/19), no additional systemic risk factors were identified during follow-up apart from those that were present before the RVO. The diagnosis of PAC was made in all patients on the basis of static and dynamic gonioscopy. None of these patients had experienced any symptoms of acute or intermittent IOP rises as a consequence of angle-closure. Fifteen patients were diagnosed with PAC glaucoma in 1 or both eyes. Sixteen subjects (84.0%) underwent peripheral laser iridotomies and 7 patients (37.0%) had lens extraction to improve angle configuration. Our study supports the belief that angle-closure may be associated with retinal vein occlusions, and should be borne in mind and excluded when investigating the patient with RVO, especially CRVO/HRVO. We suggest that gonioscopy should be done in all patients presenting with RVO.

Progression in Primary Angle Closure Eyes

To study the long-term course of primary angle closure (PAC) eyes after iridotomy. Seventy-two eyes of 72 patients diagnosed as PAC, having occludable angles with evidence of closure, but no ocular hypertension, were studied. Laser iridotomy was carried out in all eyes at baseline. Standard achromatic perimetry and tonometry were recorded at baseline and serially every 6 months, for at least 4 years. Changes on perimetry and the intraocular pressure (IOP) were analyzed. At 1 year, 10 eyes and at final review, 26 eyes had developed ocular hypertension and required topical antiglaucoma medication. Eight eyes developed visual field defects on standard achromatic perimetry, over a mean period of 6.89±2.4 years. Eyes that progressed on perimetry, had a significantly narrower angle recess, less than or equal to 10 degrees, P=0.04, and a higher baseline MD and PSD, P=0.004 and 0.03, respectively. They also showed having a larger intervisit IOP fluctuation of 8.9±2.3 mm Hg, cf stable eyes, 6.2±3 mm Hg, P=0.003, and a longer duration of follow-up, P=0.01. A third of PAC eyes, with very narrow angles, higher global indices, intervisit IOP fluctuations, and a longer duration of follow-up were observed to develop ocular hypertension. A third of the PAC eyes with hypertension, that is 11.1% overall, went on to develop PAC glaucoma.

Reply to Yip et al

Sir, We read with great interest the paper by Yip et al1 concluding that laser peripheral iridotomy (LPI) for primary angle closure (PAC) is not independently associated with cataract progression. The authors mention that cataract surgery may be an alternative treatment for occludable angles, potentially addressing both PAC and cataract blindness with one procedure. The potential complications from intraocular surgery, though, are greater than those from LPI. However, LPI has complications such as intraocular haemorrhage and inflammation, intraocular pressure (IOP) spikes, glare, diplopia, and corneal damage. These are primarily not sight threatening, but have to be always taken into consideration. Another potential complication is cataract formation, and this has been extensively reviewed by Yip et al. Despite their conclusion, there is still some controversy on this matter, with some authors supporting the opposite.2, 3 Thus, one must always be aware of such a theoretical risk after LPI. Except for the disturbances in aqueous flow in patients undergoing LPI, we suggest that, using higher-energy settings, inaccurate focusing of the laser beam, excessive or undertreated post-LPI uveitis, previous intermittent angle-closure episodes with IOP elevation, and other anatomical parameters, yet to be recognised, could be considered as possible stimuli of crystalline lens disturbance with consequent opacification. A potential complication of Nd:YAG LPI was reported by us recently.4 This involves damage to the zonules with subsequent dehiscence during routine phacoemulsification cataract surgery, affecting an otherwise healthy female with narrow angles. Our paper includes reports suggesting the same effect of LPI (both with Nd:YAG and with argon lasers), resulting in spontaneous dislocation of the crystalline lens.4 We suggested that Nd:YAG LPI may be regarded as an isolated risk factor for structural zonular damage and instability of the crystalline lens, and appropriate precautions should be taken during intraocular surgery. Regardless of the opacification being the result of the LPI, age-related or of any other cause, zonular damage could have considerable implications in subsequent cataract surgery, especially in cases where the zonules are already compromised, such as in pseudoexfoliation syndrome, previous ocular trauma, and congenital systemic diseases like Marfan's syndrome.5 Considering the large number of patients who would potentially benefit from prophylactic LPI, potential adverse sequelae of such a procedure must not be underestimated. More specifically, the possibility of cataract progression and zonular instability after LPI has important implications for patients at risk of angle closure. Choosing between primary cataract surgery and LPI is the main consideration in such cases. The therapeutic approach should be individualised and treatment benefits must always be balanced against eventual complications. Finally, we would like to congratulate the authors for their excellent contribution on a very important field of ophthalmology.

Bilateral acute angle-closure glaucoma as a complication of facedown spine surgery

Background context Multiple studies have reported that facedown positioning can result in elevation of intraocular pressure (IOP) in individuals susceptible to angle-closure glaucoma. Before advances in diagnostic modalities, prone tests were popularly performed in ophthalmology practices as provocative tests for detecting potentially occludable angles. In patients with a positive test result, direct observation shows that the anterior chamber shallows and the angle closes over time, compromising aqueous humor outflow facility. Furthermore, the degree of angle narrowing is proportional to the rise in IOP. A common scenario involving a prone position is spine surgery, which can last several hours with the patient unconscious. Purpose To report a case of a patient who developed bilateral acute angle-closure glaucoma after facedown spine surgery. Study design Case report and literature review. Methods A 68-year-old Caucasian woman presented with persistent low back and left lower extremity pain. History was remarkable for L5 radicular pain, spinal stenosis, and an L3–L4 laminectomy performed 6 months previously. Plain films showed instability at the L4–L5 level and degenerative disc disease and scoliosis at L2–L4. The patient underwent spinal fusion surgery. Results Postoperatively, the patient complained of pain in the left eye accompanied with nausea and vomiting. Ophthalmology consultation confirmed the diagnosis of bilateral acute angle-closure glaucoma, requiring medical therapy initially followed by laser iridotomies in both eyes. Conclusions Bilateral acute angle-closure glaucoma may occur as a complication of facedown spine surgery. It is essential for anesthesiologists and surgeons to be aware of this complication for accurate diagnosis and timely intervention. A preoperative evaluation by an ophthalmologist should be considered for those individuals who are at increased risk of developing angle-closure glaucoma, such as certain ethnicities, including Asians, Canadians, and Eskimos; female gender; hyperopic eyes with a shorter axial length; family history; history of previous attacks in the subject; and so forth. Prophylactic laser iridotomy in eyes with potentially occludable angles is a simple and safe office procedure that can prevent potentially devastating visual outcomes.

Changes in anterior chamber depth and intraocular pressure after phacoemulsification in eyes with occludable angles

To evaluate changes in anterior chamber depth (ACD) and intraocular pressure (IOP) after phacoemulsification in eyes with occludable angles and compare the results with those in eyes with normal open angles. Eye Clinic, Ipoh General Hospital, Ipoh, Perak, Malaysia. Patients with nonglaucomatous eyes with open angles or with occludable angles were recruited. Ocular biometric measurements (ACD, axial length [AL], lens thickness and position) and IOP (tonometry) were performed preoperatively and 1 day and 1, 4, 9, and 12 weeks postoperatively. The open-angle group and occludable-angle group each comprised 35 patients. The occludable-angle group had a shallower ACD, shorter AL, thicker and relatively anterior lens position, and higher IOP preoperatively; postoperatively, there was a significant increase in ACD and a significant reduction in IOP (P<.01). Anterior chamber deepening was inversely related to preoperative ACD in the occludable-angle group (P<.01). The mean preoperative IOP was higher in the occludable-angle group (15.77 mm Hg +/- 2.20 [SD]) than in the open-angle group (14.52 +/- 2.65 mm Hg) (P<.05). The IOP dropped progressively and significantly over 12 weeks postoperatively; the mean decrease was 2.31 +/- 0.99 mm Hg in the occludable-angle group and 0.77 +/- 1.17 mm Hg in the open-angle group. The IOP decrease in the occludable-angle group was inversely related to the preoperative IOP (P<.01). Phacoemulsification led to anterior chamber deepening and lower IOP in eyes with occludable angles, which suggests it is an option for preventing acute angle-closure attacks in eyes with occludable angles and cataract. No author has a financial or proprietary interest in any material or method mentioned.

Prophylactic laser peripheral iridotomy and cataract progression

To determine whether prophylactic laser peripheral iridotomy (LPI) for primary angle closure (PAC) is associated with cataract progression. In 1999, Mongolian volunteers aged>or=50 years were invited to participate in a longitudinal study. Glaucoma was excluded in all participants and 712 of them were selected to undergo a full ophthalmic examination as part of the study protocol. Lenses were graded and PAC diagnosed using international classification systems. In 2005, all traced participants underwent a similar dilated examination. Diagnosis of cataract progression was based on the inter-observer variation +2 standard deviations. The association between LPI at baseline and cataract progression was assessed using chi2-test and logistic regression. Of 712 participants, 158 were diagnosed with occludable angles and treated with LPI. In 2005, 137 participants (19.2%) had died, 315 (315/575=54.8%) were traced, and dilated examination was performed on 276 (48%) of them. Progression of nuclear opacity (NO), cortical, and posterior subcapsular (PSC) opacities were evident in 40 (14.5%, 95% confidence interval (CI)=10.6-19.2%), 89 (32.2%, 95% CI=26.8-38.1%), and 11 participants (4.0%, 95% CI=2.0-7.0%), respectively. Although NO was more likely to progress in those with LPI in a crude analysis (odds ratio (OR)=2.02, 95% CI=1.00-4.11, P=0.05), no evidence of an independent association was detected in multivariate analysis adjusting for age, sex, and baseline Schaffer grading (adjusted OR=1.24, 0.41-3.75, P=0.7). There was no evidence of an association between LPI and progression of PSC or cortical opacities. There is no evidence that prophylactic LPI is independently associated with cataract progression in this study.

Probing the amodal completion of asymmetrically occluded angles: A test of interpolation models

Probing the amodal completion of asymmetrically occluded angles: A test of interpolation models

New considerations on pupillary block mechanim

To study the mechanisms of pupillary block in eyes with occludable angle by ultrasound biomicroscopy. Initially, a pilot study of 13 eyes with acute primary angle-closure without medication was executed. Ultrasound biomicroscopy measurements of the angle, posterior chamber depth and iris thickness were performed in the temporal quadrant under light and dark conditions. Afterwards, ultrasound biomicroscopy measurements of iris-lens contact distance and iris-lens angle in the temporal quadrant and central anterior chamber depth were made in 32 eyes with acute primary angle-closure or intermittent primary angle-closure without medication, under light and dark conditions before and after laser peripheral iridectomy. In the pilot study, a significant decrease in the angle as well as a significant increase in the iris thickness occurred when comparing light to dark conditions. Before and after laser peripheral iridectomy (second study), significant differences were found in iris-lens contact distance (P<0.001) and iris-lens angle (P<0.001) under light and dark conditions. Also, significant differences were found in light and dark conditions, before laser peripheral iridectomy, in iris-lens angle (P=0.005), and after laser peripheral iridectomy, in iris-lens contact distance (P<0.001). No significant change occurred with anterior chamber depth. A decreased angle was correlated to an increase in iris thickness. After laser peripheral iridectomy, acute primary angle-closure or primary angle-closure eyes had an increased iris-lens contact distance and a decreased iris-lens angle. The anterior chamber depth did not change. These findings contradict the theory that pupillary block is the mechanism of acute primary angle-closure.