What is Hruby lens?

Hruby lens (Figure 1 & 2) is a high minus (originally -58.6 D) non-contact lens mounted on the slit lamp for stability. It provides a high resolution, upright image of structures in the posterior pole. …

What is the dioptric power of a Hruby lens?

Attachment to the microscope is also of advantage with the Hruby lens. The concave contact lens of 64 dioptres is best suited for detailed examination of vitreous and fundus and for measurements.

What is 90 D lens in ophthalmology uses?

The 90D is the most widely known fundoscopy lens and is to date considered the gold standard in exam rooms across the world. The small profile of the 90D coupled with its optical profile makes it a great first lens. This lens is a perfect choice for general examination and retinal imaging.

What is 90D lens examination?

This slit lamp lens is used for general examination of the fundus and small pupil examinations. This Slit lamp lens is the most popular power for non-contact fundus examination. It offers a wide-field fundus imaging out to and beyond the equator.

How do you use a Hruby lens?

Using the Hruby Lens The concave surface of the lens is placed towards the patient, and aligned so the light beam and oculars of the slit lamp shine through the lens into the patient’s eye. The microscope is then moved forward or backwards until the fundus is brought into focus.

What is Gonio lens?

3-15 Indirect gonioscopic lenses use mirrors or prisms to it has no handle to reflect the light from the irido-corneal angle (a) so that it leaves the eye perpendicular to the face of the contact lens. 3‑16, 3‑17 Goldmann three-mirror lens. The shortest mirror is for examining the angle.

Which is better 78D vs 90D?

The traditional 78D has been in use for decades and is an excellent general purpose fundus or macula lens with better stereopsis than the 90D. The Super 66 and Digital 1.0x, both 66D, provide 1.0x magnification for optic nerve measurements without applying a scaling factor.

How do you calculate vergence?

To solve vergence problems such as this one, the key is to solve U+P=V for the first lens, then treat the image thus produced as the object for the next lens. This can be continued for any number of lenses. An object is located ½ m to the left of a +4D lens, which is in turn 1 m to the left of a +3D lens.

What is the magnification of a 20D lens?

The +20D lens is the standard lens for general examination offering 3x magnification and a field of view of approximately 45°.

What is a 20D lens?

Perhaps the most recognized lens around the world, the Volk 20D is the lens that started the legacy of double aspheric lens design for BIO and is still considered as a gold standard. The contributing factors for this are the perfect balance of field of view and magnification of the 20D.

What is a Gonio lens?

What is a fundus lens?

Fundus Contact Lens: It is a diagnostic aid that makes a difficult diagnosis simple. The combination of binocular vision, great light intensity and a range of magnification powers using the fundus contact lens and the slit lamp give your ophthalmologist an excellent resolution to view the fundus.

What is Shaffer’s grading?

Shaffer System A more commonly used grading system is that of Shaffer (1960, 1962). This system describes the degree to which the angle is open rather than the degree to which it is closed. Whereas Scheie’s grade IV denotes a closed angle, on the Shaffer scale grade 4 refers to a wide-open angle.

What is Schwalbe’s line?

Schwalbe’s line (SL) is often defined as the posterior limbal zone bordering the cornea where Descemet’s membrane (DM) terminates; this feature is visible as a smooth zone when examined by scanning electron microscopy (SEM).

What is a vergence?

A vergence is the simultaneous movement of both eyes in opposite directions to obtain or maintain single binocular vision.

What does vergence mean in optics?

Vergence is a concept in ophthalmic optics in which distances are converted to a dioptric power. Vergence is defined as. where d is the absolute distance between an object and a plane of interest, and n is the refractive index of the space.

What is 5x diopter magnification?

For a 5-diopter lens of a magnifier, its magnification = 5/4 + 1 or 1.25 + 1 = 2.25x. Objects viewed under a 5 diopter lens will appear 2.25X larger than normal.

What is the Zeiss 4 mirror gonioscopy lens?

Four mirrors angled at 62° help in viewing all quadrants of the anterior chamber without rotation. The small contact surface of 9 mm diameter makes the lens very convenient to use. It has a unique detachable handle.

How do you examine Fundi?

The examination should take place in a suitably darkened room. The patient’s right eye should be examined with the examiner’s right eye, and vice versa. The patient is asked to focus on an object in the distance, and the examiner’s head is kept vertical to permit this.