Which bio to buy optometry

Similar in specifications are the Superfield and Digital WideField lenses. My SVF has a smaller mag with large field, but can get in through a smaller pupil.

This is more indicated in my current patient base who sometimes dilate poorly. On patients with findings that you need to get a better look at think: optic nerve head details, epiretinal membrane, macular edema , you want a higher magnification lens.

The 78D lens works lovely for this purpose, but if you can grab a Super 66 or its newer Digital 1. The beauty of this baby is that due to the math of the optics involved, the magnification factor is 1. This means that no matter what magnification your slit lamp is on, the mm setting you set your lamp on, this is the direct size. Three-mirrored, flanged gonioscopy lenses are required of almost all optometry students due to the fact that they are multi-purpose.

The three-mirror lens is used to teach the gonioscopy procedure due to the flange adding stability on the eye while the student learns. In addition, this lens can be used on a dilated pupil to assess the far periphery and posterior pole in more detail than a BIO lens can assess. The downside to using the flanged lenses is that they are large and cumbersome to the patient, require celluvisc, and for a routine gonio exam, require rotation on the part of the examiner to all four quadrants of the eye.

Four-mirrored gonioscopy lenses are much faster and more efficient for gonio, as they contain only 4 bullet mirrors angled for the anterior chamber angle. It provides many benefits to the examiner with very few shortcomings once mastered. Practitioners who are new to the technique are encouraged to attempt it alongside their standard procedures on all patients, especially those with large pupils initially to gain confidence.

Patients may find it more comfortable as the practitioner is out of their personal space. Magnification is relatively independent of ametropia and can be altered with lens choice.

Patient needs to be able to reach slit lamp — this can be difficult in particularly young children, patients with back or neck problems etc. The image is inverted and reversed which may confuse practitioners new to the technique. Hold the lens in your left hand to examine the right eye and vice versa. The hand may be steadied by resting your little finger against the forehead rest, and your elbow may be placed on the lens case.

Move the illumination system with their gaze. Bothersome reflections may be combated by tilting the lens away from the beam slightly e. Ensure the fine blood vessels remain in sharp focus and adjust the joystick accordingly. Figure 3A: Use of slit lamp biomicroscopy.

Figure 3B: The view of the disc by such means. When choosing a lens, the key features to consider are magnification and field of view see Table 1. Other things to consider may be cost, lens diameter from a practitioner handling point of view and usability on undilated pupils.

Often practitioners have a few at hand for different uses. The author uses a Superfield for general examination due to its wide field of view and larger diameter versus the 90D and successful use on all but the smallest of pupils, combined with a Super 66 for a high magnification view of the disc and macula, and where measurements are required. Table 1: Properties of some slit-lamp BIO lenses. This technique may be used on surprisingly young children. The edge of a raised retinal lesion such as a pigment epithelial detachment can be made more obvious when the slit beam is placed over it.

The edge of such a lesion appears to glow. A yellow filter may be attached to the most common lens types. This can aid patient comfort and purports to protect against phototoxicity. Once slit lamp biomicroscopy is mastered the Watzke-Allen test can be used as a simple and effective subjective method of distinguishing full thickness macular holes from its differential diagnoses.

A thin slit beam is centred over the macula in vertical and horizontal meridians and the patient is asked what they can see. Those with a full thickness macular hole may report a broken or narrowed beam, while those with a lamellar or pseudohole will report it as distorted or normal As with the direct ophthalmoscope, several filters on the slit lamp can be used to examine different features for example the red-free filter can be used when examining the retinal nerve fibre layer, vasculature and haemorrhages.

The axial point of light entering the eye lies on the cornea and allows for a larger field of view. Studies into ease of use, sensitivity and specificity are mixed but largely favourable in patient comfort due to patient-practitioner distance and shorter examination time.

Originally, the development of headset BIO in the s by Charles Schepens was to aid the examination of patients with retinal detachment, however it has become commonplace in other clinical settings especially paediatric examination.

Low magnification approximately 3x — not good for examination of the central fundus as small lesions may be missed. It is recommended that the patient is in the supine position which may be problematic in a standard optometric setting.

If reflections are a problem tilt the lens slightly. If the patient is able, get them to look in eight positions of gaze, tilting the lens accordingly. When looking at different areas it is important to keep a direct line between the viewing system and condensing lens.

Lens choice impacts both magnification and field of view. The latter has been suggested to be better for paediatric assessment Volk catalogue. While still more common in ophthalmology than primary optomtetric practice, this is a handy technique to master when examining patients particularly children, those who cannot reach the slit lamp for example those in a wheelchair and those that require a thorough examination of the peripheral retina.

Some practitioners advocate the use of a modified technique for using the condensing lenses mentioned above.

The headset may be cumbersome when examining younger children and scary to the patient, thus the use of a direct ophthalmoscope in conjunction with a condensing lens held in front of one eye for a monocular view or on the bridge of the nose for a binocular view when dilated is a useful method of examining the fundus from a distance. It is also used in laser treatments for some retinal conditions. The central lens provides a greater level of stereopsis compared with non-contact slit lamp biomicroscopy.

Like all reusable contact lenses there is a theoretical risk of vCJD — sterilisation or disposable equipment is required. The Goldman 3-mirror is useful as it combines a central lens for viewing the macula, with 2 mirrors for assessing the peripheral fundus as well as a gonioscopy mirror Figure 4.

Figure 4: The Goldmann three-mirror contact lens. Mydriatics come in two forms: parasympathetic antagonists such as Tropicamide, or sympathetic agonists such as Phenylephrine. Parasympathetic antagonists are used to paralyze the iris sphincter muscle while sympathetic agonists are used to stimulate the iris dilator muscle. Through this enlarged pupil the examiner is able to view the center and periphery of the retina. A technique commonly used with BIO is scleral depression. This complements the dynamic viewing of the retina and vitreous.

The forward and inward curvature of the globe in the anterior portion of the eye obscures and prevents far peripheral viewing Therefore, scleral depression or special contact lenses such at Goldman 3-Mirror contact lens is needed to indent the scleral and bring the peripheral retina into view..

To depress the sclera, a scleral depressor is placed against the sclera either on the globe or on the eyelid overlying the globe and gentle firm pressure is applied. By looking into the depression the doctor can view more of the peripherals of the fundus. Scleral depression is also a helpful way of examining patients who complain of flashes and floaters or patients who are at risk of peripheral retinal anomalies such as tears or detachments. When patients have high risk symptoms, scleral depression is highly recommended to allow complete viewing of the retina.

Create account Log in. Main page. Getting Started. Recent changes. View form. Table 1. Alternative to 78D if the practitioner elects to use just one lens. Ideal option if thepractitioner uses a single lens. Ideal for pediatric examination, when scleral indentation is required and for patients with nystagmus. Useful when slit lamp examination is not possible. Current Issue. All rights reserved.

Reproduction in whole or in part without permission is prohibited. Indirect Lenses and Their Typical Use. View the posterior pole using a slit lamp.