Anne M. V. Brooks

Congenital fibrosis of the vertically acting extraocular muscles maps to the FEOM3 locus

Abstract. The diagnosis of congenital fibrosis of the extraocular muscles (CFEOM) encompasses several different inherited strabismus syndromes characterized by congenital restrictive ophthalmoplegia affecting extraocular muscles innervated by the oculomotor and/or trochlear nerves. The OMIM database (http://www.ncbi.nlm.nih.gov/Omim/) currently contains four familial CFEOM phenotypes: CFEOM1–3, which map to the FEOM1–3 loci (MIM 135600, 602078, 604361), respectively, and congenital fibrosis of the vertically acting extraocular muscles (MIM 600638), reported in a single family without a corresponding genotype. We have had the opportunity to study the reported family with this fourth phenotype and now demonstrate that their phenotype can be reclassified as CFEOM3 and that it maps to FEOM3, flanked by D16S498 to 16qter, with a maximum lod score of 6.0.

Congenital Fibrosis of the Vertically Acting Extraocular Muscles: A New Group of Dominantly Inherited Ocular Fibrosis with Radiologic Findings

BACKGROUND The authors studied a family with a form of congenital fibrosis of the extraocular muscles different from any group previously reported. METHODS A careful examination was done of all affected and all, except one, unaffected members of a family of 15 members extending over three generations. The authors performed computed tomography on five affected and four unaffected family members. RESULTS All affected family members showed complete loss of vertical ocular movement but largely free horizontal movement except for variable restriction of adduction in some members. A variable degree of ptosis was present, ranging from gross to nil, but with poor levator function and an absent Bell phenomenon in all affected members. All affected members showed superficial keratopathy, many with corneal scarring. Ocular alignment showed considerable variation. Refractive error and amblyopia also were variable. Computed tomographic scan indicated reduction in size of the extraocular muscles, particularly the superior recti with intracranial ventricular asymmetry in three of five patients examined, and abnormality in shape of the eye globes in two patients. CONCLUSIONS The findings indicate a new group best described as dominantly inherited congenital fibrosis of the vertical-acting extraocular muscles, which is part of the syndrome of congenital ocular fibrosis. Computed tomographic scanning suggested that the clinical picture was produced by changes present in the orbit, but intracranial ventricular asymmetry also was present in some patients and asymmetry of the eye globes in others.

Astigmatic change 1 year after excimer laser treatment of myopia and myopic astigmatism

Purpose: To evaluate the surgically induced astigmatism (SIA) 1 year after excimer laser photorefractive astigmatic keratectomy (PARK) and photorefractive keratectomy (PRK). Setting: Royal Victorian Ear and Eye Hospital, Melbourne, Australia. Methods: This study comprised 333 PARK patients and 155 PRK patients treated with a VISX 20/20 excimer laser and followed prospectively for 12 months. Vector analysis of the change in astigmatism was used to calculate the SIA in the PRK group and the percentage of astigmatism corrected in the PARK group. Results: Among patients with low cylinders astigmatic correction varied greatly, particularly in those treated for large amounts of myopia. The spherical PRK treatments yielded a mean induced postoperative astigmatism of 0.47 diopter. There was a linear relationship between this inadvertent SIA and increasing myopia. Conclusion: Excimer laser surgery for myopia creates a low degree of random, unpredictable SIA that may be the result of irregular epithelial thickening during postoperative healing. This creates a background noise of astigmatic change upon which the targeted astigmatic correction is superimposed.

Clinical features at presentation of anterior segment pigment dispersion syndrome.

One hundred and twenty patients with anterior segment pigment dispersion syndrome were reviewed in order to ascertain the features of the condition and form some idea of their significance. Patients were regarded as having pigment dispersion syndrome on the basis of heavy trabecular mesh pigmentation with at least one other feature of the condition. Although common in men, 44 patients, or a little over one‐third, were women. Average age at presentation was 47.8 years with women presenting 10 years later than men. Intraocular pressure was very variable at presentation being less than 20 mmHg in 23 patients. Some patients with elevated pressure had no field loss. Variable myopia was recorded in 38 patients; 30 patients were not myopic. Anterior chamber depth was also variable, the average being 3.0 mm, but six patients had a depth of 2.2 mm or less. The syndrome is extremely variable in its features at presentation. The mild hypoplasia and the hypoperfusion of the iris previously described is consistent with the laxity of the iris noted by Ritch and colleagues.

Predictability of excimer laser treatment of myopia and astigmatism by the VISX Twenty-Twenty

Background: To determine the predictability of excimer laser photorefractive keratectomy (PRK) to correct myopia, astigmatism, or both between −1.00 and −19.00 diopters (D). Setting: Royal Victorian Eye and Ear Hospital, East Melbourne, Australia. Methods: This study comprised 1218 consecutive eyes treated with a VISX TwentyTwenty excimer laser and followed prospectively for 12 months. Low myopia was treated with one ablation zone (6.0 mm), high myopia with two ablation zones (5.0 and 6.0 mm), and extreme myopia with three ablation zones (4.5, 5.0, and 6.0 mm). Maximum spherical treatment was 15.00 D at the corneal plane. Data were analyzed to determine the predictability of the postoperative outcomes by preoperative refraction. Results: Nine hundred eighty eyes (80.5%) were available for the 12 month follow‐up. The predictability of refraction and uncorrected and best corrected visual acuities progressively decreased with increasing myopia, although a comparable percentage of spherical correction was achieved at each diopter of myopia. The likelihood of losing lines of best corrected visual acuity and corneal haze increased with increasing myopia. Conclusion: These data can be used to counsel patients of likely outcomes of excimer laser PRK to correct myopia.

Central retinal vein occlusion in pseudoexfoliation of the lens capsule.

In surveying an extensive group of patients with unilateral pseudoexfoliation of the lens capsule certain interesting points emerged, particularly on the incidence of central retinal vein occlusion in this condition, and perhaps in glaucoma also. A total of 284 patients with unilateral pseudoexfoliation of the lens capsule were examined clinically after an ophthalmic and general history were taken. Mean intraocular pressure (IOP) was 30.9 mmHg in the affected eye and 18.1 mmHg in the unaffected eye. Central retinal vein occlusion occurred in 10 affected eyes but no unaffected eyes and always in affected eyes with a rise in IOP. Average IOP in the affected eye with central retinal vein occlusion was 37.5 mmHg (range 26−54 mmHg); in the unaffected fellow eye it was 18.0 mmHg (range 11−28 mmHg). Although the process involved in producing pseudoexfoliation of the lens capsule may contribute to the precipitation of central retinal vein occlusion, these findings suggest the rise in IOP is the more important cause. This may also be so in other forms of glaucoma.

Identifying anterior segment crystals.

A series of 22 patients with crystals in the anterior segment of the eye was examined by specular microscopy. Of 10 patients with hypermature cataract and hyperrefringent bodies in the anterior chamber cholesterol crystals were identified in four patients and in six of the 10 in whom aspirate was obtained cholesterol crystals were demonstrated in three, two of these having shown crystals on specular microscopy. In 10 patients with intracorneal crystalline deposits, cholesterol crystals were found on specular microscopy, including one case of Schnyders crystalline corneal dystrophy. Of two patients with multiple myeloma, corneal crystals were demonstrated in one. Crystals of the anterior segment of the eye are most likely to be cholesterol, and identification is important for future treatment.

Determination of the Nature of Corneal Crystals by Specular Microscopy

The use of the specular microscope as a noninvasive in vivo method of identifying cholesterol crystals in two cases of crystalline corneal deposits is described. This illustrates the advantage of using the specular microscope under living conditions with a much higher magnification than is obtained with the slit lamp. Attention is drawn to the wider applications of this method.

Comparison of colour Doppler imaging of orbital vessels in elderly compared with young adult patients.

Purpose: Colour Doppler imaging provides an estimate of the velocity of blood flow in vessels supplying the eye. Methods: To assess changes in orbital blood flow with age, we used a method to study peak systolic velocity in 20 young normal patients, mean age 25.2 ± 2.4 years and 30 elderly normal patients, mean age 69.5 ± 7.9 years. Results: Peak systolic velocity was significantly higher in the central retinal artery and the temporal division of the posterior ciliary artery in elderly patients. There was greater variation in the peak systolic velocity readings in the distal part of the ophthalmic artery in the elderly than in the younger group. There was greater variation in the pulsatility index in the central retinal artery in young subjects. Conclusions: Though not large, these differences suggest changes in the orbital blood vessels with age which could affect the development of disease processes in elderly patients. These changes should be taken into account when assessing blood flow in elderly patients.

Excimer laser filtration surgery.

PURPOSE In order to remove precisely scleral tissue overlying Schlemms canal with minimal trauma as an outpatient procedure under local anesthetic, we used a VisX Twenty/Twenty excimer laser. METHODS We performed excimer laser filtration in three enucleated pig eyes, seven enucleated human eyes, and seven eyes of seven patients with severe glaucoma. Precise ablation to Schlemms canal was confirmed by scanning electron microscopy in the enucleated eyes. For the patients, a local anesthetic was used, and a custom-made holder was used to mobilize the conjunctiva and fix the eye. RESULTS A functional sclerostomy was obtained with 1,780 to 5,965 pulses, using a 2 x 1-mm slit. In our mean follow-up of nine months (range, six to 12 months) the excimer laser filtration technique achieved controlled filtration in five of seven patients and minimized conjunctival trauma. One patient subsequently underwent cataract extraction. CONCLUSIONS This study indicates that excimer laser filtration is an effective technique for achieving filtration in glaucoma. It may reduce the complications of glaucoma filtration surgery, particularly the incidence of shallow anterior chamber postoperatively, as it leaves the trabecular meshwork intact.