Comparison of bifocal and progressive addition lenses on aviator target detection performance.

The objective of this project was to determine if the type of presbyopic correction worn by aviators, conventional bifocal versus progressive addition lenses (PAL's), differentially affects aviator visual search performance. Experienced aviators, most with tactical fighter aircraft experience, searched for high-contrast targets under simulated dawn/dust (mesopic) lighting conditions (approximately 3.0 cd/m2) while wearing either a standard bifocal (ST-25) or PAL spectacle correction. Latency of locating high-contrast targets under these viewing conditions was differentially affected by the type of presbyopic correction used. Specifically, compared to a standard bifocal (ST-25), a PAL correction (Varilux Infinity) significantly lowered the time needed to locate static targets at a cockpit instrument viewing distance (83 cm). Accuracy of target location responses was not affected by the type of correction used. In addition, 7 months post-experiment, 7 of the 12 participants (58%) indicated that they used their PAL correction exclusively when flying the T-39 Sabre Liner. Three subjects (25%) used their PAL correction intermittently (primarily at night) when flying and two subjects preferred not to use the PAL's. These results suggest that relative to bifocals, speed of responding to static targets at intermediate viewing distances may be improved by wearing PAL's, and that subjects were able to adapt to PAL lenses quickly in a laboratory setting, using them later in a functional aviation environment.

The fate of eyewear in aircraft ejections.

Ejection from jet aircraft has been exhaustively studied from many perspectives; e.g., causes of ejection, types and causes of ejection injuries, etc. Curiously, no reports exist describing the fate of eyewear in ejections. Many pilots wear required corrective lenses during flight operations, and many wear tinted lenses. What happens to these during ejection? What injuries are a result of the eyewear? What factors can be identified that influence retention of the eyewear and severity of related injury? Do contact lenses provide significant advantages? There were 48 ejections occurring between 1977 and 1990 that involved corrective or tinted lens use that were retrospectively examined using Naval Safety Center records and personal questionnaires. There were five contact lens wearers included. Retention rates were calculated as functions of several variables. Although 37 of 46 lost all lenses, each instance of retention occurred with visor down, oxygen mask on, helmet properly secured, and at lower ejection speeds. Related injuries were minor and occurred in only 20%. The utility and need for enforcement of standard operating procedures (i.e., mask on, helmet secured, and visor down) was clearly demonstrated. Only 19 of 46 clearly met all 3 criteria. Contact lens users were too few to allow meaningful conclusions.

Photo-refractive keratectomy (PRK): threat or millennium for military pilots?

The development of the excimer laser, which is capable of correcting myopia without leaving obvious scars as does radial keratotomy, makes it certain that this promising but very new modality is something the military aviation community will be facing in the immediate future. Methods of detection are available, but are expensive and time-consuming. Should military aviation permit or even sponsor a group of PRK student pilots in order to observe them closely, and then perhaps use this new modality in place of contact lenses or even spectacles?

Variations on the theme of involutional entropion and the Quickert repair.

The late Marvin Quickert originated a lower lid entropion repair successful especially in recurrent cases. Probable reasons for its success is correction of all three main conditions predisposing to entropion, namely increased horizontal length, excessive vertically mobile preseptal orbicularis, and lax retractors, whereas other entropion procedures correct only one or two factors. A bridge flap of lid is created by an incision at the base of the tarsus, and this is then transected vertically in its outer third. The amount of horizontal redundance determined, a rectangle of full thickness lid is excised, and the ends reapproximated. Wies type sutures are placed approximating superior anterior lamella to inferior posterior lamella. Redundant skin is excised laterally and the entire skin incision closed. A Wies procedure resulting in immediate ectropion can easily be converted to this procedure.

Surgical repair of extreme bilateral ptosis by modified anterior approach.

This report describes an apparently unique anterior approach surgical repair of a congenital ptosis which had progressed with age and had functionally almost blinded the patient. Poor tear production was the reason that neither conventional maximal levator resection nor sling procedures were considered desirable. A method of levator resection with no interference with the conjunctiva is presented, although since performance of the surgery, a similar method has been published. A few caveats of ptosis surgery are offered.

Evacuation of orbital hematoma by continuous suction.

An orbital hematoma, unusual in its delayed onset and association with indirect trauma, is described. Successful therapy consisted of continuous suction through a polyethylene catheter. Various methods of therapy, conservative and surgical, have been described in the ophthalmic literature, but no previous report was found of the employment of continuous suction.

Ophthalmic screening of the mentally defective.

Rationale, technique, and equipment required for mass, but accurate, ophthalmic screening of mental defective children is described. A review of the various diagnoses of systemic and ocular diseases of children attending special retarded schools is presented. Conditions in which the author thought correction was warranted are discussed. The philosophy of dealing with such patients is presented.