Most big lens manufacturers now have their own lens ordering softwear, and these often contain a lens comparison module, such as Essilor's 'Opsys' system. Figure 2 shows its use for a comparison between a -8.00 lens in CR39 and 1.8 glass. The Essilor Opsys system also enables you to digitally rotate a lens (to scale) so that the patient can view it from all angles (Figure 3).

Pub Lights forbar

View PDF    Sometimes a patient may enquire about the different lens options and how thick they may be. This is especially for a myope interested in paying more for higher index materials. The myopic patient needs to know how much thinner the lens will be and be able to relate this to the cost of the lens. Hyperopes tend to be less bothered by the 'value' for the thickness of their lens, and base their thinking on how thick they 'feel' the lens is. Telling a hyperope that the lens is actually 0.5mm thinner may be meaningless, if the lens still appears thick.To calculate the thickness of a lens, you first need to calculate the sag, of both surfaces, and take in to account the centre thickness of a minus lens or the centre thickness of a plus one.Meniscus lens From Figure 1 (above)t + s2 = e + s1sot = e + s1 - s2There are two approximate sag formulae, the first from when crown glass was the norm in the optical world s = y2 F1000 Where y = half the diameter of lensToday we are more likely to use it in the following format as this allows the index of the lens to be taken in to accounts = y2 F2000 (n-1)These approximate formulae are best used on the 'power' of the lens rather than each surface as the accuracy achieved by looking at both surfaces is negated by the inaccuracies of the approximate methods. Strangely the accurate sag calculations are just as easy as the approximations.Exact sag formula is:s = r -vr2 - y2Where you will need to calculate the radius of curvature using:n-1 = rFExample: Calculate the sag of a -11.00 curve, diameter 50mm in crown glass.Using the accurate methodn-1 = 1-1.523 = 0.0475 mF 11.00r = 47.5mm s = r - vr2 - y2s = 47.5 - v47.52 - 252s = 47.5 - v2256.2 - 625s = 47.5 - v1631.2s = 47.5 - 40.38s = 7.1mmUsing an approximate formulas = y F 2000 x n-1s = 25 x 25 x111046s = 6.57mmWhen calculating the thickness it is essential that you remember to include the edge thickness in plus lenses and the centre thickness in minus ones.You will need to check with the manufacturer to find the centre thickness of a specific material, but as we could be dealing with fractions of a millimetre between manufacturers, it is a useful guide to assume that glass and higher index resins were 1mm thick and CR39 2mm. Any thinner than this and the lens could be a potential danger for your patient.For plus lenses you need to be aware of the minimum edge 'thinness'. A lens any thinner than 0.6mm will be dangerously thin, but in a plastics frame the edge should ideally be about 1mm and in metal a little thicker at 1.8mm. Exceptions to this are supras and rimless. A supra needs to be 2-3mm thick to take the supra cord. So care needs to be taken in dispensing a plus lens in to a supra, as the lens will need to be thicker than in a full rim equivalent. Be aware that if you dispense a 'thinner' aspheric lens into a supra frame this would also need to be made a little thicker. This may defeat the object of a thinner lens, but it would still be 'flatter', and consequently cosmetically better. In a rimless frame the edge needs to satisfy a minimum thickness, which may vary with the method of attachment. A useful guide would be to keep it at 2-3mm.More often that not, it is easier to compare the thickness of a new lens to that of the old. If you know what the patient is wearing you can tell them it will be x per cent thinner/thicker. The curve variation factor (CVF) can be used to compare thicknesses of lenses to that of Crown glass (1.523)n CVF 1 498 1.05 (5% thicker than crown)1.523 1.00 1.7 0.75 (25% thinner than crown)1.8 0.65 (35% thinner than crown)1.9 0.58 (42% thinner than crown)Companies such as Norville, Essilor and Nikon produce dispensing mats which illustrate lens thickness and help explain thicknesses to patients.Most big lens manufacturers now have their own lens ordering softwear, and these often contain a lens comparison module, such as Essilor's 'Opsys' system. Figure 2 shows its use for a comparison between a -8.00 lens in CR39 and 1.8 glass. The Essilor Opsys system also enables you to digitally rotate a lens (to scale) so that the patient can view it from all angles (Figure 3).Patients generally want thinner and lighter lenses, and expect a knowledgeable practitioner to help them through the maze of indices and lens forms. It's important that you dispense what the patient wants and needs, rather that what you decide they are going to have. Always dispense a lens for a reason, and 'because that's what I always do' is not one of those reasons. We saw in the last part of this series (Optician, January 12, 2007) the importance of dispensing the correct index, very relevant when talking about thickness of lenses. Later in this series we shall look at some other aspects of thinner high index lenses, such as chromatic aberration. ?? Janet Carlton is dispensing manager at the City University Optometry Clinic

When calculating the thickness it is essential that you remember to include the edge thickness in plus lenses and the centre thickness in minus ones.

What’s interesting about afternoon lighting is that it will change with the time of year. During the winter season in North America, it will get dark outside earlier. This means consider lights that have the ability to dim to match how the outside light changes.

You will need to check with the manufacturer to find the centre thickness of a specific material, but as we could be dealing with fractions of a millimetre between manufacturers, it is a useful guide to assume that glass and higher index resins were 1mm thick and CR39 2mm. Any thinner than this and the lens could be a potential danger for your patient.

The myopic patient needs to know how much thinner the lens will be and be able to relate this to the cost of the lens. Hyperopes tend to be less bothered by the 'value' for the thickness of their lens, and base their thinking on how thick they 'feel' the lens is. Telling a hyperope that the lens is actually 0.5mm thinner may be meaningless, if the lens still appears thick.

Minibar lightingideas

Today we are more likely to use it in the following format as this allows the index of the lens to be taken in to account

Remember how we said that lighting can come in all shapes, sizes, colors, and forms? (Actually in that sense, lighting is kind of like beer.) While it’s true there are an infinite number of products out there, we’ve tracked down a few of the most popular styles of lights to try right now.

Modernbar lightingideas

Patients generally want thinner and lighter lenses, and expect a knowledgeable practitioner to help them through the maze of indices and lens forms. It's important that you dispense what the patient wants and needs, rather that what you decide they are going to have. Always dispense a lens for a reason, and 'because that's what I always do' is not one of those reasons.

Untappd for Business can help increase your revenue while providing powerful insight and analytics about what your guests are drinking locally.

It’s important to create an environment where your clientele feels comfortable while also staying true to your brand. Different types of lighting say different things about your establishment. There are countless options, but in general lighting comes down to a few categories.

Pretty popular right now, suspended lighting (sometimes referred to as pendant or drop lights) extends down from the ceiling. Suspended lights hang from a cord, chain, or rod, offering a striking piece of modern lighting. You can hang them over the bar or even tables. Suspended lights that are used in a group are great for ambient lighting while those used independently can be great for accent lighting.

Elegant and sophisticated, chandleries set a specific tone for your brewery, bar or restaurant. Higher-end establishments often use chandeliers to make a statement. They can be larger lighting fixtures and they typically have more bulbs, so that’s a consideration in terms of upkeep. But chandeliers are great for setting a mood.

Best Lighting: Accent lighting. Place brighter lights in a few strategic spots to create that ambience while also keeping the general tone darker inside.

We saw in the last part of this series (Optician, January 12, 2007) the importance of dispensing the correct index, very relevant when talking about thickness of lenses. Later in this series we shall look at some other aspects of thinner high index lenses, such as chromatic aberration. ?

Companies such as Norville, Essilor and Nikon produce dispensing mats which illustrate lens thickness and help explain thicknesses to patients.

More often that not, it is easier to compare the thickness of a new lens to that of the old. If you know what the patient is wearing you can tell them it will be x per cent thinner/thicker.

To calculate the thickness of a lens, you first need to calculate the sag, of both surfaces, and take in to account the centre thickness of a minus lens or the centre thickness of a plus one.

Homebar lighting

Best Lighting: Those that dim. On the spectrum, consider lights that can easily go from warm to brighter hues as the light outside dims earlier.

For plus lenses you need to be aware of the minimum edge 'thinness'. A lens any thinner than 0.6mm will be dangerously thin, but in a plastics frame the edge should ideally be about 1mm and in metal a little thicker at 1.8mm. Exceptions to this are supras and rimless. A supra needs to be 2-3mm thick to take the supra cord. So care needs to be taken in dispensing a plus lens in to a supra, as the lens will need to be thicker than in a full rim equivalent. Be aware that if you dispense a 'thinner' aspheric lens into a supra frame this would also need to be made a little thicker. This may defeat the object of a thinner lens, but it would still be 'flatter', and consequently cosmetically better. In a rimless frame the edge needs to satisfy a minimum thickness, which may vary with the method of attachment. A useful guide would be to keep it at 2-3mm.

For example, if you are a family-friendly space operating during the day, your lighting should be different than a twenty-one-plus space that sees most of its traffic come through at night. All these factors contribute to the type of lighting that you’ll use in your brewery or restaurant.

A fairly standard way of lighting a restaurant, bar, or brewery, wall lights offer a large area of illumination. Many establishments use wall lights because they act as the main source of light. While this isn’t the most creative of options, wall lights certainly get the job done well.

General rule of thumb: When it’s dark outside you’ll most likely want to create a slightly dimmer atmosphere inside. Bars and restaurants tend to lower their lights at night to create a cozy, comfortable environment.

Bar LightingLED

In this month's look at calculations in practice, Janet Carlton describes how best to calculate what is all imoprtant to most patients - lens thickness

Accent lighting plays off your ambient light or lack thereof. With accent lighting, you place brighter lights in certain spots around the room to illuminate a space or area without lighting the whole room. It’s a strategy that can be great for showing off pieces of art, an interesting part of your space like an herb wall or garden, or even just your tap list. Accent lighting is where you can get really creative and playful.

These approximate formulae are best used on the 'power' of the lens rather than each surface as the accuracy achieved by looking at both surfaces is negated by the inaccuracies of the approximate methods. Strangely the accurate sag calculations are just as easy as the approximations.

The morning is a time for everyone—folks on their way to work who just want to grab a coffee, those who have just finished a workout and want to stay for a bite, families on their way to school, etc. If your establishment gets a lot of light while you’re open in the morning, the mood you want to set is a comfortable place for customers to start their day.

What may seem like a very tiny detail such as lighting can actually have a big impact on your business. The lighting sets the mood of your operation and illustrates your brand to your potential customer base.

This is your main source of lighting that your establishment doesn’t receive from the natural ambient light. These fixtures typically illuminate your different rooms from overhead or on the wall.

Designing your restaurant, bar, or brewery sets the tone for your entire establishment. How you outfit your space speaks to your larger brand and will attract potential customers. We have several top tips on how to design the overall look of your brewery or restaurant, but often it’s the smallest of details that matter. Such as your lighting.

Sometimes a patient may enquire about the different lens options and how thick they may be. This is especially for a myope interested in paying more for higher index materials.

Bar lightingdesign

If you’re a little bit more of an artistic or creative operation, consider can lighting. Also known as recessed lighting, this type of fixture illuminates a hollow part of the ceiling while simultaneously lighting up the entire room. One of the best advantages of can lighting is that the bulb can normally be dimmed, so it’s a great option for daytime-to-nighttime operations.

For one of the best forms of accent lighting, consider track lighting. This type of illumination consists of smaller light bulbs attached along a long track on the ceiling. They’re great for bars and breweries because track lights can normally be dimmed.

Simply put: This is the natural light that comes into your bar, restaurant, or brewery from the outside. If you have big windows or roll-up garage doors, you will definitely be able to take advantage of your ambient lighting. Since this is natural light, many different types of lighting fixtures work well with it.

The first consideration when it comes to your restaurant, bar, or brewery lighting is the time of day you operate. Taking into account your hours of operation will help determine what type of lighting is best for you.