John A. Dyer

A 48-Year Clinical and Epidemiologic Study of Keratoconus

From 1935 through 1982, keratoconus was newly diagnosed in a total of 64 residents (35 males and 29 females) of Olmsted County, Minnesota. There were no significant trends in incidence rates over time; the overall average annual rate was 2.0 per 100,000 population. The age-specific incidence rates were greatest in the younger groups. The incidence rates did not differ significantly by sex. On Dec. 31, 1982, the overall prevalence rate was 54.5 per 100,000 population. At the time of diagnosis, keratoconus was unilateral in 26 patients (41%) and bilateral in 38 patients (59%). Follow-up of the patients showed that survival did not differ significantly from that of the general population. The cumulative probability of survivorship without corneal transplantation for more than 20 years after diagnosis was greater than 80%.

Torsional diplopia after transantral orbital decompression and extraocular muscle surgery associated with graves'orbitopathy

Graves orbitopathy can be associated with horizontal, vertical, and torsional diplopia. Of 428 patients treated with transantral orbital decompression, 21 had incycloduction (mean, 12.8 degrees; range, 5 to 20 degrees) and five had excycloduction (mean, 12 degrees; range, 5 to 20 degrees). All 26 patients had had recessions of the medial or inferior rectus muscle (or both) before onset of torsional diplopia. Mean recession was 5.5 mm (range, 4 to 10 mm) and 5.3 mm (range, 2 to 10 mm) of medial rectus muscle and inferior rectus muscle, respectively. An A pattern was often associated with the condition. Superior oblique tenectomy and inferior oblique myectomy were performed most frequently for incycloduction and excycloduction, respectively. Superior oblique tenectomy induced a mean incycloduction decrease of 7.1 degrees (range, 0 to 12 degrees). Exotropia in downgaze was decreased, and a small ipsilateral hyperdeviation was induced. Bilateral inferior oblique myectomy in one patient decreased excycloduction 10 degrees without inducing new deviation. At follow-up (mean, 63.7 months) after last strabismus operation, 15 patients with incycloduction and two with excycloduction had no diplopia.

Role of Cycloplegics in Progressive Myopia

Abstract Atropine sulfate 1% was instilled in both eyes of 86 children (172 eyes) on a daily basis for a period of two to eight years. No untoward changes in intraocular pressure, pupillary response, accommodation, or appearance of the ocular fundi were noted. A comparison with a similar group of children having only glasses prescribed during a similar time span revealed that atropine is effective in reducing the progression of myopia in children; a permanent reduction in the degree of myopia may be achieved. Relaxation of accommodation by means of cycloplegic drugs may be a safe and effective treatment of myopia.

Sensitivity to vasovagal maneuvers in normal children and adults

In 15 male and 15 female healthy subjects who were 10 to 48 years of age, we studied alterations in heart rate and finger blood flow in response to the cold pressor test and four strong vasovagal maneuvers: diving response (apneic facial exposure to an ice water bag), Valsalva maneuver (forced expiration against a column of mercury to 40 to 50 mm Hg), unilateral carotid sinus massage, and oculocardiac reflex (inflation of a Honan balloon against one eye). Peripheral vasoconstriction as a consequence of the diving response paralleled the vasoconstriction from the cold pressor test, but it preceded the bradycardia that resulted from the diving response maneuver. In contrast, the rate of finger blood flow was high during the bradycardia that followed stage 4 of the Valsalva maneuver. Changes in heart rate correlated with age for the diving response, the Valsalva maneuver, and the oculocardiac reflex. Changes in heart rate and finger blood flow were not dependent on sex. The change in heart rate noted with the diving response was significantly correlated with that noted with the Valsalva maneuver and the oculocardiac reflex. Changes in finger blood flow did not correlate with changes in heart rate for any maneuver. This study provides a response profile of relative sensitivities to strong vasovagal maneuvers in normal children and adults.

Acquired Divergent Strabismus: Presumed Metastatic Gastric Carcinoma to the Medial Rectus Muscle

A patient with rapidly progressive metastatic gastric carcinoma developed diplopia and diminished adduction of the right eye. The right medial rectus muscle belly was enlarged, as shown by computed tomography. This case is unusual, because gastric carcinoma comprises only 1% of orbital metastases and less than 5% of all orbital metastases localize to extraocular muscle.

Bilateral medial rectus muscle recession and lateral rectus muscle resection in the treatment of congenital esotropia.

In a retrospective study of 36 patients with congenital esotropia treated surgically by bilateral medial rectus muscle recession and lateral rectus muscle resection, we found that 22 patients (61%) had not required further surgery and that 14 patients (39%) had required further corrective surgery. Seven of these 14 patients had overcorrections and seven had undercorrections. Patients who required a second operation were significantly younger (mean age, 12 months) than those who did not (mean age, 23 months). The most common second surgical procedure was bilateral tenotomy or disinsertion of the inferior oblique muscle. Bilateral medial rectus muscle recession and lateral rectus muscle resection is useful in severe (50 prism diopters or more) congenital esotropia. The surgical success rate may be improved with bilateral inferior oblique muscle disinsertions or tenotomies in patients with inferior oblique muscle overaction. Accurate preoperative examinations in patients old enough to cooperate may help avoid overcorrection and undercorrection.

Lack of Global Vagal Propensity in Patients with Oculocardiac Reflex

Background: Profound bradycardia during ophthalmic surgery is a rare but potentially serious event. Little is known about the predictability of the oculocardiac reflex. Methods: Four vagotonic maneuvers were performed on six patients who had profound oculocardiac reflex (3- to 10-second asystole) during eye surgery, the results of which were compared with 30 previously studied control subjects. Electrocardiographs were monitored during the following vagotonic maneuvers: diving response (apneic facial immersion), Valsalva maneuver, ocular compression, and carotid sinus massage. Results: The degree of heart rate slowing as a result of diving response, Valsalva maneuver, and, notably, ocular compression did not differ when these patients were compared with the 30 previously studied control subjects. Carotid sinus massage produced significantly ( P = 0.01) more bradycardia in the six patients (mean ± standard deviation, -24% ± 6%) than in the 30 control subjects (-12% ± 7%). The heart rate response to pressure on the eyes did not correlate with prior intraoperative oculocardiac reflex. Conclusion: The discrepancy in heart rate sensitivity between surgical extraocular muscle tension and ocular compression may be due to different sensory receptors and brain stem processing for the trigeminally mediated oculocardiac reflex. Carotid sinus massage may help predict low heart rates during eye surgery.

Anterior Subcapsular Cataracts As a Possible Adverse Ocular Reaction to Isotretinoin

Inquiries to David C. Herman, M.D., Mayo Clinic, 200 First St. S.W., Rochester, MN 55905. A 45-year-old woman who was not taking any medications and had no known allergies was prescribed isotretinoin (40 mg twice daily) on Dec. 12, 1985, for chronic cystic acne. Durxad ing the ensuing 14 weeks, the patient noted dryness of her eyes and skin but no visual disturbances. Chemistry and hematology proxad files checked before and during the treatment with isotretinoin were normal. The isotretinoin was discontinued after 14 weeks because the

Marginal myotomy of the medial rectus with lateral rectus resection as a secondary procedure for esotropia.

Between 1964 and 1982, 89 marginal myotomies were performed, 70 on the medial rectus with lateral rectus resection as a combined secondary procedure for esotropia. Successful realignment was attained in 51% of the cases (for both distance and near measurements); undercorrection occurred in 34% (either distance or near), and overcorrection in 14% (either distance or near). Further operation was required in 17%, of which 4% were for overcorrection. Initial postoperative alignment was maintained at subsequent follow-up. The degree of change in deviation did not correlate with the degree of resection of the lateral rectus or the degree of medial rectus myotomy. Marginal myotomy of the medial rectus with lateral rectus resection is a useful procedure that should be part of the repertoire of all strabismus surgeons.

Ophthalmic Manifestations of Narcolepsy

We reviewed the records of 755 patients in whom narcolepsy was diagnosed between 1979 and 1983. In a subset of 405 previously undiagnosed and untreated patients, the following variables were assessed: the subspecialty in which the condition was diagnosed, age and sex of the patients, family history, expressed symptoms in the total group, symptoms in patients whose condition was diagnosed by ophthalmologists, laboratory aids used for diagnosis, treatment, and outcome.