William S. Hagler

Radial perivascular retinal degeneration: a key to the clinical diagnosis of an ocular variant of Stickler syndrome with minimal or no systemic manifestations.

PURPOSE To identify the genetic defect and present the ocular and extraocular findings in a large pedigree of predominantly ocular Stickler syndrome. DESIGN Observational case series. METHODS An eight-generation pedigree with hereditary retinal detachments was retrospectively and prospectively studied. Clinical information was obtained by medical records, telephone interviews, medical questionnaires, detailed ophthalmologic examinations, physical examinations, and personal observations. Linkage analysis of the COL2A1 gene was performed on 21 family members, and mutation analysis was performed on three family members. RESULTS The pedigree consisted of 100 affected individuals. The ocular findings, frequently bilateral, consisted of radial perivascular retinal degeneration (RPRD) (100%), vitreous syneresis (100%), high myopia (76%), retinal detachment (65%), presenile cataract development (occurring before 50 years of age; 78%), and glaucoma (18%). Most (70%) of the retinal detachments occurred between 4 and 18 years of age. Extraocular manifestations, characteristic for Stickler syndrome, were detected in only four of 100 (4%) affected individuals. Linkage analysis with COL2A1 flanking markers showed evidence for linkage to the COL2A1 locus. The COL2A1 gene analysis identified a mutation converting a codon TGC for cysteine(86) to a premature termination codon in the alternatively spliced exon 2. CONCLUSIONS A variant of Stickler syndrome, caused by mutations in exon 2 of COL2A1, may present in families with all of the ocular findings and no clinically identifiable extraocular findings associated with Stickler syndrome. The predominant ocular findings are a congenitally abnormal vitreous and an acquired radial perivascular retinal degeneration that may lead to complicated childhood and adult retinal detachment.

Results of surgery for ocular Toxocara canis.

It has been shown that the diagnosis of ocular Toxocara canis is highly accurate when the typical clinical findings are associated with a positive ELISA titer in the serum of 1:8 or greater. The inflammatory reaction in this disorder can be devastating and not infrequently leads to a tractional detachment of the posterior pole or a rhegmatogenous detachment and/or a progressive cyclitic membrane leading to phthisis bulbi. We have recently performed vitreoretinal surgery on 17 patients with complications secondary to ocular T canis. Fifteen patients had stability or improvement in visual acuity, and one patient had a decrease in visual acuity. There were no surgical complications present. The clinical features, operative techniques used, and postoperative course are summarized, and the indications for the used of various surgical procedures are presented.

Ophthalmomyiasis Interna Causing Visual Loss

Ophthalmomyiasis interna caused severe intraocular inflammation and loss of vision in two eyes. In the first eye, the organism was found in the vitreous and created a severe uveitis; a second-stage larva of Hypoderma lineatum was later removed from the anterior chamber. Phthisis bulbi ensued with loss of all vision. In a second eye, a subretinal maggot was observed to produce tracks in the pigment epithelium, with subretinal and vitreous hemorrhage. Severe uveitis and traction retinal detachment later developed. Despite successful reattachment of the retina, visual acuity remained only light perception. These cases demonstrate that ophthalmomyiasis interna is not always a benign condition.

Rhegmatogenous Retinal Detachment Following Chorioretinal Inflammatory Disease

Preexisting ocular inflammatory disease was responsible for 44 cases (1.7%) of rhegmatogenous retinal detachment in a large series of consecutive retinal detachments. Characteristics of retinal detachments following ocular inflammatory disease include a longer duration of the detachment, fewer observable retinal breaks, a higher incidence of visible vitreous membranes and preoperative macular puckers, a younger age distribution, and a higher incidence of phakic patients. In comparing the group of postinflammatory rhegmatogenous retinal detachments with detachments not associated with inflammation, the following characteristics did not show any statistically significant difference: sex, the eye involved, the status of the ciliary epithelium, the presence or types of retinal folds, the rate of operative complications, or the rate of reattachment at six months.

Eye Tumor Identification Tests Using Semiconductor Detectors

The 32P eye tumor identification test is being reevaluated using semiconductor detectors. Diagnostic tests for both anterior and posterior lesions of the uveal tract are being performed on patients, and a comparison is being made between the conventional G. M. eye tumor counter and the silicon lithium drifted, Si(Li), silicon surface barrier and silicon avalanche beta detectors. Results from 31 tests performed to date indicate that among the detectors tested, the Si(Li) posterior detector gives the most consistent, sensitive and reliable results. For tumors of the uveal tract a beta energy threshold as determined by the detector window thickness and electronic noise can be as high as several hundred keV. Surface barrier detectors placed in suitable probes can therefore also be used for these lesions. For more deeply imbedded tissue tumors, such as lesions of the choroid, iris or retina, the silicon avalanche detector shows considerable promise because of its greater sensitivity for lower energy betas.

Applanation-Schiøtz Disparity afrer Retinal Detachment Surgery Utilizing Cryopexy

Previous reports of applanation-Schiøtz disparity following retinal detachment surgery involved patients whose detachments were treated with diathermy and scleral buckling. In 73 patients with retinal detachments treated by cryopexy and scleral buckling, applanation and Schiøtz pressures were measured before and after surgery. In the postoperative period, applanation tension values were significantly higher than Schiøtz values in the operated eyes only; the mean disparity was 6 mm Hg, with a range of 0 to 14 mm Hg. Sex, age, surgical aphakia, and length of time after surgery did not influence the data. Placement of the buckle, rather than extent of cryopexy, appeared to be the main factor in producing this disparity. Ophthalmologists who utilize the Schiøtz tonometer should be aware of the various conditions, including retinal detachment surgery, which produce low ocular rigidity.

Medical Problems in Eye Tumor Identification

The accurate identification of eye tumors continues to be a difficult medical diagnostic problem. The several non-nuclear clinical diagnostic techniques that have been used, such as direct and indirect ophthalmoscopy, slit lamp examination, transillumination, fluorescein angiograph, ultrasonography and direct analysis of the subretinal fluid, have all resulted in a high percentage of misdiagnoses. This has resulted in eyes being enucleated that did not contain malignant melanomas, but more tragically, eyes with malignant tumors were not enucleated, resulting in the death of the patient due to the metastatic spread of the tumor. At the present state of development, the 32p uptake test offers the best diagnostic method. For tumors of the uveal tract both G. M. and semiconductor detectors can be used. Detectors more sensitive to lower energy betas are needed to diagnose deeper lying tumors and to study the possible correlation between percent 32p uptake and the particular cell type of the tumor.