Combining spectral domain optical coherence tomography of retinal nerve fiber layer and noncontact tonometry in mass glaucoma screening during the World Glaucoma Week.

PURPOSE: This study reports the combination of noncontact tonometry and spectral domain optical coherence tomography (SD-OCT) in mass glaucoma screening in the Lebanese population. METHODS: This cross-sectional study included Lebanese individuals who participated in a glaucoma screening campaign in March 2018 and March 2019 for World Glaucoma Week. Intraocular pressure (IOP) was measured by noncontact tonometry. Optic nerve head (ONH) and retinal nerve fiber layer (RNFL) scans were obtained using SD-OCT. Glaucoma suspects were defined as individuals having an IOP above 21mmHg in at least one eye and/or RNFL thinning in either the superior or the inferior quadrant. RESULTS: Among the 1116 individuals who were examined, 15.5% were found to be glaucoma suspects based upon their IOP readings, 15.5% based on OCT, and 3.0% based on both criteria combined. The mean vertical and horizontal disc diameter was 1.75±0.23mm and 1.57±0.22mm, respectively. Eyes that were suspects by OCT with normal IOP had thinner corneas when compared to eyes with normal OCT and high IOP (512.25µm vs. 559.12µm, P<0.0001). CONCLUSION: SD-OCT can be an easy and relatively fast component of mass glaucoma screening in addition to IOP measurement. Further studies are needed to establish this combination as a valid glaucoma screening method.

Multiple CYP1B1 mutations and incomplete penetrance in an inbred population segregating primary congenital glaucoma suggest frequent de novo events and a dominant modifier locus.

Primary congenital glaucoma (PCG) is an autosomal recessive disorder associated with unknown developmental defect(s) in the anterior chamber. Recently, we reported three distinct mutations in CYP1B1, the gene for cytochrome P4501B1, in 25 Saudi families segregating PCG. For this report, we analyzed 37 additional families and confirmed the initial finding of decreased penetrance. Mutations and intragenic single-nucleotide polymorphisms (SNPs) were also analyzed from direct sequencing of all CYP1B1 coding exons. Eight distinct mutations were identified: G61E, R469W and D374N, the most common Saudi mutations, account for 72, 12 and 7%, respectively, of all the PCG chromosomes. Five additional homozygous mutations (two deletions and three missense mutations) were detected, each in a single family. Affected individuals from five families had no CYP1B1 coding mutations, and each family had a unique SNP profile. The identification of eight distinct mutations in a single gene, on four distinct haplotypes, suggests a relatively recent occurrence of multiple mutations in CYP1B1 in Saudi Arabia. These data demonstrate decreased penetrance of the PCG phenotype in the Saudi population, because 40 apparently unaffected individuals in 22 families have mutations and haplotypes identical to their affected siblings. Two individuals were subsequently diagnosed with glaucoma and two others had abnormal ocular findings that are consistent with milder forms of glaucoma. Analysis of these 22 kindreds suggests the presence of a dominant modifier locus that is not linked genetically to CYP1B1. Linkage and Southern analyses excluded three candidate modifier loci.

Detachment of Descemet's membrane.

PURPOSE: To determine predisposing factors, best method of treatment, and the final outcome in cases of Descemet's membrane detachment. SETTING: A tertiary care teaching eye hospital. METHODS: All cases of Descemet's detachment from January 1986 to May 1994 were retrospectively reviewed. Twelve eyes of 11 patients with partial or total detachment of Descemet's membrane were identified. Patients with small localized detachments at the incision area were excluded. RESULTS: All but one patient had surgical repair. Ten eyes had successful reattachment after up to four attempts at repair. Methods of repair included intracameral air or sulfur hexafluoride (SF6) 20% gas, with or without corneal sutures. After a followup of 3 to 79 months, eight eyes retained clear corneas, four eyes developed corneal edema and scarring, and two required penetrating keratoplasty. No definite predisposing factor could be identified, although four eyes had preoperative diagnoses of glaucoma and recent corneal edema. CONCLUSION: Surgical repair with injection of intracameral air or SF6 20% was successful in most cases of Descemet's membrane detachment. A preoperative diagnosis of glaucoma and a recent episode of corneal edema may increase the risk of detachment.

Mutations in CYP1B1, the gene for cytochrome P4501B1, are the predominant cause of primary congenital glaucoma in Saudi Arabia.

The autosomal recessive disorder primary congenital glaucoma (PCG) is caused by unknown developmental defect(s) of the trabecular meshwork and anterior chamber angle of the eye. Homozygosity mapping with a DNA pooling strategy in three large consanguineous Saudi PCG families identified the GLC3A locus on chromosome 2p21 in a region tightly linked to PCG in another population. Formal linkage analysis in 25 Saudi PCG families confirmed both significant linkage to polymorphic markers in this region and incomplete penetrance, but it showed no evidence of genetic heterogeneity. For these 25 families, the maximum combined two-point LOD score was 15.76 at a recombination fraction of .021, with the polymorphic marker D2S177. Both haplotype analysis and homozygosity mapping in these families localized GLC3A to a 5-cM critical interval delineated by markers D2S2186 and D2S1356. Sequence analysis of the coding exons for cytochrome P4501B1 (CYP1B1) in these 25 families revealed three distinctive mutations that segregate with the phenotype in 24 families. Additional clinical and molecular data on some mildly affected relatives showed variable expressivity of PCG in this population. These results should stimulate a study of the genetic and environmental events that modify the effects of CYP1B1 mutations in ocular development. Furthermore, the small number of PCG mutations identified in this Saudi population makes both neonatal and population screening attractive public health measures.

Congenital glaucoma, limb deformities, skeletal dysplasia, and facial anomalies: report of another family.

We report on a family of first cousin parents in which 2 of 3 children presented with congenital glaucoma, large anterior fontanelle, prominent forehead, hypertelorism, down-slanting palpebral fissures, broad and flat nasal bridge, broad nasal tip, anteverted nostrils, high-arched palate, gingival hypertrophy, pectus excavatum, prominent coccyx with skin fold, short fingers and toes, single palmar creases, flexion deformities of fingers, club feet, and osseous malformations. Despite some clinical differences, their anomalies are very similar to those seen in a new and rare autosomal recessive entity described by ter Haar et al. [1982]. Differential diagnoses are discussed.

A gene for primary congenital glaucoma is not linked to the locus on chromosome 1q for autosomal dominant juvenile-onset open angle glaucoma.

BACKGROUND: Primary congenital glaucoma is an uncommon autosomal recessive condition that results from a developmental defect in the trabecular meshwork and anterior chamber angle, manifesting in the neonatal or infantile period with increased intraocular pressure, corneal enlargement and edema, and optic nerve cupping with consequent loss of vision. Nothing is known about its genetic location. PATIENTS AND METHODS: Linkage analysis was performed in 25 primary congenital glaucoma Saudi Arabian families with six polymorphic DNA markers on chromosome 1q in a region that has shown tight linkage to a locus for autosomal dominant juvenile-onset open angle glaucoma (GLC1A). Twenty-four of these families are highly consanguineous. RESULTS: Each family was shown separately to exclude the 8-centimorgan (cM) interval containing the GLC1A locus. Four families independently demonstrated overlapping regions of exclusion (theta < or = -2) that spanned the entire 8-cM interval. Assignment of a primary congenital glaucoma locus in this region could be excluded by a cadre of 21 families because a primary congenital glaucoma disease locus did not segregate in an autosomal recessive manner on haplotypes constructed with markers in this region. For all families, no affected individuals demonstrated homozygosity of alleles in regions tightly linked to the GLC1A locus. CONCLUSION: These results exclude the 8-cM region on chromosome 1q shown to contain the GLC1A locus from containing a disease locus for primary congenital glaucoma in this population of 25 Saudi Arabian families.

The glaucomas in pseudophakia.

The glaucomas in pseudophakia are not uncommon. Because they can be related to different mechanisms, each case should be evaluated individually. Once glaucoma has been established and medication fails to maintain the intraocular pressure at a safe level, several options are available. As a group, the glaucomas are considered both difficult to manage with medications and also at high risk for failure of filtration surgery. Trabeculectomy adjuvated with anti-metabolites, draining implants, and cyclodestructive procedures are all effective procedures. Although complications and loss of vision as a consequence of glaucoma surgery are not frequent, they were reported by several authors. The likelihood of any given treatment to preserve the quality of life should be discussed with each patient and should be part of the decision-making process. This article reviews studies on the glaucomas in pseudophakia published from October 1994 to September 1995.

Transscleral neodymium:YAG laser cyclophotocoagulation for end-stage glaucoma, refractory glaucoma, and painful blind eyes.

We used transscleral Neodymium:YAG laser cyclophotocoagulation (TSYLCC) to treat 47 patients (47 eyes) with end-stage, refractory, or absolute glaucoma. The mean pretreatment intraocular pressure (IOP), 40.5 +/- 10.8 mm Hg, decreased a mean of 13 +/- 8 months following treatment to 15.6 +/- 10.6 mm Hg, a statistically significant change (P < .05). Our overall rate of success (final IOP < or = 25 mm Hg, with or without medications) was 79% (37 eyes). Early complications included pain (11 eyes) and inflammation (13 eyes); late complications included hypotony (7 eyes), high IOP (5 eyes), and decreased visual acuity (4 eyes). TSYLCC seems to be a safe, effective, and convenient outpatient procedure.

Neodymium:YAG laser iridotomy in the initial management of phacomorphic glaucoma.

Acute angle-closure glaucoma can be triggered by a mature or intumescent cataract, and occurs in eyes with open angles, as well as in those with narrow, occludable angles. This is encountered more in developing countries, where patients present late. They tend to wait until the cataract becomes mature, because it is common belief among these patients that cataracts should not be operated on until vision drops to the level of hand movements or light perception. The authors reviewed the charts of 10 patients who were treated for phacomorphic glaucoma, by first undergoing neodymium:YAG (Nd:YAG) laser iridotomy. In all patients, the acute angle-closure glaucoma attack could be reversed or prevented by the iridotomy, before subsequent cataract extraction. The value of Nd:YAG laser iridotomy in the initial management of phacomorphic glaucoma is discussed.

The results of glaucoma surgery in aniridia.

Aniridia is an uncommon disorder that may be associated with glaucoma that is usually refractory to conventional medical and surgical therapy. In this study, we report our experience with the surgical management of glaucoma in aniridia in 17 eyes of 10 patients. A total of 45 surgical procedures were performed. The mean preoperative intraocular pressure was 38 mm Hg. The intraocular pressure was ultimately controlled successfully in 11 eyes (intraocular pressure range, 8 to 20 mm Hg) with a mean of 2.8 surgical procedures required in successful cases. Trabeculectomy controlled the intraocular pressure in one eye, but it was successful in only 9% of cases in which it was performed. Cyclocryotherapy was successful in five eyes (25% of cases in which it was performed), although complications of phthisis bulbi and progressive cataract occurred. We detail our experience with the Molteno implant, which was successful in five eyes (83% of cases in which it was performed). We have found this type of drainage device to be effective in controlling intraocular pressure in aniridic eyes when previous attempts at control have failed.

The glaucomas in aphakia and pseudophakia.

Intraocular pressure may become temporarily or permanently elevated at various intervals following cataract surgery. There are several mechanisms by which glaucoma develops as a complication of the cataract extraction itself. The presence of a pseudophakos may or may not contribute to the pathogenesis. Important diagnostic clues include the anterior chamber depth, the presence or absence of an iridectomy, gonioscopic findings, and the appearance of the optic nerve head. Life-long medical treatment is frequently justified, as alternative laser or surgical modalities may not be successful. The exact causes for high failure of filtration surgery in aphakic eyes is not clearly understood; scarring of the conjunctiva, the vitreous, and altered characteristics of the aqueous humor have all been incriminated. Current research to improve surgical success includes the development of effective artificial drainage implants or the use of pharmacologic modulators of wound healing, which promote filtration by preventing scar formation.

Clinical experience with the Molteno implant in advanced infantile glaucoma.

The alternatives in the management of infantile glaucoma refractory to conventional treatment are quite limited and unrewarding. We did a retrospective study of 49 patients (53 eyes) under 12 years of age with advanced, uncontrolled glaucoma who each underwent implantation of a single-plate Molteno implant in one stage. Over the follow-up period ranging from 6 months to 3 years (mean 18 months), 36 of the 53 eyes (68%) had an intraocular pressure less than or equal to 21 mm Hg and were considered a success. Fourteen eyes (26%) required further glaucoma surgery, 2 eyes developed severe chronic hypotony, and 1 eye lost light perception following endophthalmitis. The number of anti-glaucoma medications was decreased from a mean of 2 (+/- 1) to 1 (+/- 1). The probability for success of the Molteno implant in controlling glaucoma increased with the age of the patient. Six eyes (11%) were late failures, most probably due to fibrous encapsulation of the bleb. Complications observed were: prolonged hypotony and flat anterior chamber, retinal detachment, migration of the tube, erosion of the tube through the conjunctiva, and an ingrowth of fibrous tissue in the anterior chamber. We consider the Molteno implant to be a reasonable option in the management of difficult cases of infantile glaucoma.

Cyclocryotherapy in selected cases of congenital glaucoma.

We investigated the efficacy of cyclocryotherapy, a procedure which destroys the ciliary epithelium, thereby decreasing the production of aqueous humor, by retrospectively studying 109 eyes with advanced primary congenital glaucoma that had undergone the procedure. The eyes were divided into two groups: group I comprised 75 eyes (69%) that had undergone conventional surgical procedures for congenital glaucoma prior to cyclocryotherapy; group II, 34 eyes (31%) that had not undergone any such previous procedures. All eyes were followed for at least 12 months after the last cyclocryotherapy. With "success" defined as "having an IOP greater than or equal to 8 mmHg, greater than or equal to 19 mmHg with or without medication," the success rate in all eyes was 30%, with no significant difference between the success rates in groups I and II (P greater than .05). Chronic hypotony (IOP less than 8 mmHg) was found in seven eyes (6%). Six eyes (6%) developed cataract during the course of treatment with cyclocryotherapy. Cyclocryotherapy appears to be a reasonable addition to the treatment of eyes with advanced, uncontrolled, primary congenital glaucoma.

Neodymium-YAG laser goniotomy vs surgical goniotomy. A preliminary study in paired eyes.

Goniotomy and trabeculotomy are two widely accepted modalities of treatment for primary congenital/infantile glaucoma. Both procedures may be associated with complications. We treated 10 patients with bilateral, symmetrical congenital/infantile glaucoma and clear corneas. One eye of each patient underwent surgical goniotomy under general anesthesia, and the other was treated by neodymium-YAG laser goniotomy under oral chloral hydrate sedation (average energy, 76.6 mJ). Mean pretreatment intraocular pressure in the surgical goniotomy group was 28.4 mm Hg and in the laser goniotomy group it was 29.5 mm Hg, decreasing to 23.6 and 23.1 mm Hg, respectively, following treatment. There was a strong positive correlation (r = .81) between the percent of intraocular pressure change after laser treatment (mean, -14.4%) and that after surgery (mean, -14.3%). Our preliminary results indicate that neodymium-YAG laser goniotomy is an effective, noninvasive alternative to surgical goniotomy.

The long-tube single plate Molteno implant for the treatment of recalcitrant glaucoma.

One hundred cases of recalcitrant glaucoma were operated with a long tube single-plate Molteno implant (LSMI). At the median follow-up of 15 months an intraocular pressure of less than or equal to 19 mm Hg was obtained in 64 of the 87 eyes (73%) which have a minimum follow-up of 6 months (secondary non-neovascular glaucomas = 19; congenital glaucomas = 26; secondary neovascular glaucomas = 12). The interval probability (percentage +/- standard error) of obtaining a successful result (IOP less than or equal to 19 mm Hg) was 79% (+/- 13) at twelve months from surgery, and 53% (+/- 24) at the eighteen month interval. The least favorable results were obtained in the secondary non-neovascular glaucomas. Complications observed included choroidal detachment (24%), tube exposure (4%), tube-endothelium contact (6%), plus band keratopathy, fibrous ingrowth, traction retinal detachment and corneal ulcers. Seventeen cases needed repeated surgery for the management of complications. In order to decrease the post-operative hypotony, we have been using a tourniquet suture around the tube at the time of implantation to occlude it temporarily and limit the outflow.

Extracapsular cataract extraction using a temporal limbal approach after filtering operations.

We reviewed the charts of 29 patients who underwent extracapsular cataract extraction after filtering surgery. Seven of these patients also had simultaneous implantation of a posterior chamber intraocular lens. All eyes were operated on using a temporal limbal approach. The median postoperative follow-up was 13 months. There was no statistically significant difference between the preoperative and postoperative intraocular pressures, but there tended to be an increase in the number of antiglaucoma medications administered postoperatively. None of these patients, however, required further surgery for intraocular pressure control.

Neodymium-YAG laser posterior capsulotomy for the treatment of aphakic and pseudophakic pupillary block.

We examined five patients who developed pupillary block after extracapsular cataract extraction. One of the patients also had a posterior chamber intraocular lens implanted at the time of cataract operation. In all five patients, pupillary block was promptly relieved by Nd:YAG laser posterior capsulotomy.

Limbal- vs fornix-based conjunctival trabeculectomy flaps.

We studied 20 patients with uncontrolled symmetric glaucoma who had undergone bilateral trabeculectomy after having received the same medical or laser treatment to both eyes. In each patient, the techniques and suture material used in the two eyes were identical, and the surgeon was the same. The only variable was the type of conjunctival flap used: one eye received a limbal-based flap and the other a fornix-based flap. These patients were followed up from three to 13 months (median, 8.5 months). There was no difference between the two groups in postoperative anterior chamber depth, intraocular pressure control, occurrence of hyphema, size and shape of the bleb, or the rate of complications. The fornix- and limbal-based conjunctival flaps in trabeculectomy were found to yield comparable results in terms of safety and short-term efficacy of pressure control.