1. This document discusses fitting rigid gas permeable (RGP) contact lenses to toric corneas.
2. It describes various lens designs including spherical, aspheric, toric base curve, and spherical power equivalent lenses.
3. Guidelines are provided for selecting the appropriate lens type based on factors such as the amount of corneal toricity and whether the corneal cylinder matches the spectacle cylinder. Formulas and spreadsheets are also described to calculate the lens power.
Fitting an Astigmatic Patient is really a challenging.Though fitting a Toric Cornea is another challenge in CL Dispensing practice.This Slide will give you a basic considerations in RGP Toric lens.
It contains Examination Protocol for Contact Lenses along with information about pre-requisites for fitting a Contact Lens. A helpful guide for all Students, Eye Care Practitioners (Optometrist, Ophthalmologist).
Scleral lens is a large rigid contact lens with a diameter range of 15mm to 25mm. Its resting point is beyond the
corneal borders, and are believed to be among the best vision correction options for irregular corneas. Wearing scleral lens also can postpone or even prevent surgical intervention as well as decrease the risk of corneal scarring.
Fitting an Astigmatic Patient is really a challenging.Though fitting a Toric Cornea is another challenge in CL Dispensing practice.This Slide will give you a basic considerations in RGP Toric lens.
It contains Examination Protocol for Contact Lenses along with information about pre-requisites for fitting a Contact Lens. A helpful guide for all Students, Eye Care Practitioners (Optometrist, Ophthalmologist).
Scleral lens is a large rigid contact lens with a diameter range of 15mm to 25mm. Its resting point is beyond the
corneal borders, and are believed to be among the best vision correction options for irregular corneas. Wearing scleral lens also can postpone or even prevent surgical intervention as well as decrease the risk of corneal scarring.
Troubleshooting bifocals and Market Availability in Nepal
Bifocals in Anisometropia
Prismatic Effect in Bifocal
Bifocal Prescription
Bifocals in High Astigmatism
Troubleshooting bifocals and Market Availability in Nepal
Bifocals in Anisometropia
Prismatic Effect in Bifocal
Bifocal Prescription
Bifocals in High Astigmatism
This presentation is mainly focused on progressive addition lenses along with the brief description of single vision reading lenses ,bifocal and trifocals which are the other options available for the management of presbyopia. It also include a short description on the fitting of the PAL. PAL is the most used option worldwide for the management of presbyopia .PAL is also used in the management of progressive myopia and the studies shows it is more effective than the bifocal lenses. PAL are more effective in myopia management when the myopia comes along with the near esophoria and accommodation lag. In this modern century personalised progressive lenses are the most effective in matching the need of the patients.
Various laser lenses have been introduced following Goldmann 3- mirror and Goldmann fundus contact lens for retinal photocoagulation.
Below described some of the time-tested lenses in widespread use. Precise knowledge of these lenses is necessary for safe retinal photocoagulation.
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
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TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
NVBDCP.pptx Nation vector borne disease control programSapna Thakur
NVBDCP was launched in 2003-2004 . Vector-Borne Disease: Disease that results from an infection transmitted to humans and other animals by blood-feeding arthropods, such as mosquitoes, ticks, and fleas. Examples of vector-borne diseases include Dengue fever, West Nile Virus, Lyme disease, and malaria.
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
1. FITTING THE TORIC CORNEA WITH RGP LENSES
Lens designs available:
A. Spherical Base and Peripheral Curves
B. Aspheric Lenses
C. Spherical Base Curve and Toric Peripheral Curves
D. Toric Base Curves
E. Prism Ballasted Front Surface Cylinders
F. Hydrogel Torics
2. CHOOSING THE TYPE OF LENS TO USE
Corneal cylinder approximately equals the spectacle cylinder
(with 2.00 D. or less of corneal toricity)
Rigid spherical or aspheric lens
-tear layer corrects cylinder equal to the corneal
toricity, therefore no cylinder power required in CL
Example: -2.50 -1.50 x 180 spectacle Rx
43.50 @ 180; 45.00 @ 090 K-reading
Toric hydrogel lens
-need toric lens since there is no power in the tear layer
3. CHOOSING THE TYPE OF LENS TO USE
Corneal cylinder with little or no spectacle cylinder
-use spherical hydrogel lens
(rigid lens would induce residual astigmatism
due to a toric tear lens)
Example: -3.00 -0.25 x 180 spectacle Rx
43.00 @ 180; 44.25 @ 090
4. CHOOSING THE TYPE OF LENS TO USE
Corneal cylinder =>2.00 D. and corneal cylinder does not equal
spectacle cylinder
-rigid spherical lens would create residual astigmatism
-use a toric base curve rigid or toric hydrogel.
-with high cylinders (over 3.00 D.) RGP bitoric lenses
usually give better vision (rotation of the RGP usually
has insignificant effect on vision).
5. CHOOSING THE TYPE OF LENS TO USE
Corneal cylinder does not equal spectacle cylinder
(with less than 2.00 D. corneal toricity).
A spherical rigid lens would create residual astigmatism :
Use:
1. toric hydrogel
2. prism ballast front cylinder
6. CHOOSING THE TYPE OF LENS TO USE
With-the-rule corneal toricity and against-the-rule residual
astigmatism with a non-flexing lens use:
1. thin RGP which will flex and correct the residual
astigmatism.
2. a toric hydrogel to correct the cylinder.
Example: K-reading 43.00 @ 180; 45.00 @ 090
Spectacle Rx -3.00 -1.25 x 180
If RGP does not flex there is -0.75 x 090 over-refraction
If RGP lens is made thin and flexes 0.75 D. the
residual astigmatism would be corrected
7. Using Spherical Base Curve RGP Lenses on Toric Corneas
A. Advantages:
1. simple
2. inexpensive
B. Disadvantages:
1. Lenses may not center well
2. May be excessive movement
3. May cause corneal distortion
4. Fluctuations in vision-because of lens
movement and decentration
5. Lens flexure
8. 1. If corneal toricity less than 2.00 D. then spherical lens
is lens of choice
2. On 2 to 3 D. corneal toricity may be able to use sphere
3. On K fit- results in excessive movement and decentration
4. Best compromise fit (common rules of thumb)
-base curve = 1/3 of toricity added to flat K
-mean K minus 0.50 D.
5. Diameter: same as for near spherical cornea-depends on
lid position
6. Peripheral curves- same as standard spherical lenses.
Using Spherical Base Curve RGP Lenses on Toric Corneas
9. FITTING A TORIC CORNEA WITH A SPHERICAL BCR
On K fit (lens BCR matches flat meridian of cornea):
-horizontal band of touch on WTR corneas
-edge stand-off at 12 and 6 o’clock
-excessive movement and rocking on blinking
-lens tends to ride high if held up by lid or drops and
rides low
-lens may be easily lost from eye
due to edge catching
lens edge due to stand-off
10. FITTING A TORIC CORNEA WITH A SPHERICAL BCR
Spherical base curve on a 3.00 D.
toric cornea. Horizontal band of
touch.
Lenses fitted this flat typically
ride ride high if pulled up by the
upper lid or drop and ride low.
11. FITTING A TORIC CORNEA WITH A SPHERICAL BCR
Lens fitted steeper than K
-lens rests on cornea in mid-periphery
-dumbell or H fluorescein pattern
-Best compromise fit:
Lens fitted steeper than K by approx. 1/3 of corneal
toricity
Example: 43.00/44.50 cornea 43.50 base curve lens
-Can cause corneal distortion with spectacle blur
12. FITTING A TORIC CORNEA WITH A SPHERICAL BCR
Best compromise fit is one where
lens base curve is steeper than K
by about 1/3 of corneal toricity.
For example if K’s are 42.00/45.00,
then lens base curve should be
43.00 D. This gives a “dumbell” or
“H” pattern.
This lens is fitted too steep with
lens resting on cornea at the
peripheral curve of the lens.
13. Use when there are high amounts of corneal toricity
(2.00 D. or more corneal toricity)
Physical fit of lens to cornea is much better than with
a spherical lens. “Saddle on the horse” concept.
Toric Base Curve RGP Lenses
14. Overall and optical zone diameter determination:
-use same overall diameter (OAD) and optical zone
diameter (OZD) as you would for a spherical lens.
-OAD determination based on lid positions
-OZD based on lens diameter and pupil size
FITTING TORIC BASE CURVE RGP LENSES
15. FITTING TORIC BASE CURVE RGP LENSES
Base curve radii selection:
a. select the flat meridian of lens to match flat corneal meridian
-with a large diameter-large optical zone lens you may
need to go 0.25 D flatter than flat K and with a
small lens you may have to go 0.25 or 0.50 D. steeper
than flat K.
b. Select the steeper meridian of the base curve to give
the CL about ¾ of the toricity of the cornea.
Example: K-readings: 43.00 @ 180; 47.00 @090
CL base curve: 43.00/46.00 D (7.85/7.34 mm)
16. Use the same criterion used for spherical base curve lenses
-for example if for a given diameter/optical zone of a
spherical lens the SCR is 1.5 mm flatter than the BCR
do the same for the toric BCR lens
Keep difference between meridians of the SCR the same as BCR
-For example if BCR 7.70/7.30 mm then SCR maybe
9.20/8.80 mm.
This keeps the OZD round and secondary clearance even.
FITTING TORIC BASE CURVE RGP LENSES
Peripheral (secondary) curve selection:
17. FITTING TORIC BASE CURVE RGP LENSES
Fluorescein pattern of a toric BCR lens on a toric cornea
should look like a spherical lens on a spherical cornea.
7.6/8.0 BCR on toric cornea
Even fluorescein pattern
Toric base curve lens with
both meridians too steep.
Try next lens 0.50 D. flatter
in each meridian.
18. FITTING TORIC BASE CURVE RGP LENSES
Toric BCR RGP lens with too much toricity in the lens.
Note the central pooling and the touch at 12 & 6 o’clock
19. A toric BCR lens with too little toricity in the lens. Looks
like a spherical lens on a low toricity cornea with a central
band of touch.
FITTING TORIC BASE CURVE RGP LENSES
20. Using diagnostic lenses to fit toric corneas:
a. can use spherical BCR diagnostic lenses to determine
fit on flat meridian and use 3/4 rule for steep
meridian.
b. best to use toric base curve lenses
most used set has 2.00 D. toricity
3.00 D. and 4.00 D. sets useful
SPE designed sets are best
FITTING TORIC BASE CURVE RGP LENSES
21. Spherical Power Equivalent (SPE) Toric Base Curve Lenses
Design:
-toric base curve lens with a front toric to give spherical
power effect when on the eye.
-in air the cylinder power will be the same as the
difference in the base curve toricity specified
in diopters.
-example: base curve toricity 42.00/46.00;
power plano/-4.00 in air.
FITTING TORIC BASE CURVE RGP LENSES
22. FITTING TORIC BASE CURVE RGP LENSES
SPE diagnostic sets:
Possible 2.00 D. Toric Spherical Power Equivalent Diagnostic Set
(diameter 9.5 mm; OZD 8.0 mm; PCW 0.3 mm)
Base Curves (D) Base Curves (mm) Powers Secondary curves Peripheral curves
39.00/41.00 8.65/8.23 -3.00/-5.00 10.2/9.8 12.5/12.1
39.50/41.50 8.54/8.13 -3.00/-5.00 10.1/9.7 12.3/11.9
40.00/42.00 8.44/8.04 -3.00/-5.00 10.0/9.6 12.0/11.6
40.50/42.50 8.33/7.94 -3.00/-5.00 9.9/9.5 11.7/11.3
41.00/43.00 8.23/7.85 -3.00/-5.00 9.8/9.4 11.3/10.9
41.50/43.50 8.13/7.76 -3.00/-5.00 9.7/9.3 10.9/10.5
42.00/44.00 8.04/7.67 -3.00/-5.00 9.6/9.2 10.5/10.1
42.50/44.50 7.94/7.58 -3.00/-5.00 9.4/9.0 10.4/10.0
43.00/45.00 7.85/7.50 -3.00/-5.00 9.2/8.8 10.3/9.9
43.50/45.50 7.76/7.42 -3.00/-5.00 9.0/8.7 10.1/9.8
44.00/46.00 7.67/7.34 -3.00/-5.00 8.8/8.5 10.0/9.7
44.50/46.50 7.58/7.26 -3.00/-5.00 8.6/8.3 9.9/9.6
45.00/47.00 7.50/7.18 -3.00/-5.00 8.4/8.1 9.8/9.3
45.50/47.50 7.42/7.11 -3.00/-5.00 8.2/7.9 9.7/9.4
Lenses designed to have an axial edge lift of 0.12 mm in the flat meridian
23. Spherical Power Equivalent (SPE) Toric Base Curve Lenses
Advantage of SPE lenses:
-corrects patient's cylinder when the spectacle cylinder
equals corneal toricity
-example: K-readings: 43.00/46.00;
spectacle cylinder -3.00 D.
-if lens rotates on eye it has no detrimental effect on
patient's vision-tear lens compensates.
-ideal for diagnostic lenses since it allows for easy,
accurate over-refractions.
FITTING TORIC BASE CURVE RGP LENSES
24. FITTING TORIC BASE CURVE RGP LENSES
With SPE lens (or any diagnostic lens) on the eye, do a
sphere-cylinder over-refraction.
Using the diagnostic lens base curve and power with the
over-refraction to determine lens to order.
Compensate for any base curve change from the diagnostic lens.
Keep it simple, calculate power needed in each meridian
and order lens. Do not worry about what the front surface
will be, let lab calculate that.
Compare lens to order using K’s & spectacle Rx to that
using the diagnostic lens and over-refraction. Both should
give same lens power to order.
25. Determining the lens power to order in a toric BCR lens
Using the spectacle Rx and K-readings
43. 00
K-READING
46.50
43.50
BASE CURVE
-0.50
+0.50
LACRIMAL LENS
-0.50
+0.50
LACRIMAL LENS
-6.50
-2.00
SPECT. RX
-6.00
-2.50
CL RX
47.00
43.00
26. Mandell-Moore form for calculating bitoric lens power.
Available on the RGPLI web site: http://www.rgpli.org
27. 45.00
45.00
DIAGNOSTIC CL BC
46.50
43.50
BC TO BE ORDERED
+1.50
-1.50
CHANGE IN LL P0WER
-3.00
-3.00
DIAG. LENS POWER
-1.50
-1.00
OVER-REFRACT. CHANGE IN LL P0WER
+1.50
-1.50
-6.00
-2.50
CL POWER
Determining lens power using a diagnostic lens and
over-refraction.
28. Excel spreadsheet for calculating bitoric lens power using
the K-readings and spectacle Rx.
Available on the web at http://www.****
CALCULATION OF POWER FOR BITORIC RGP LENSES
USING K-READINGS AND SPECTACLE RX
Enter the requested values in the blank (white) cells.
Flat K Steep K
K-readings 45.00 49.00
Sphere Cylinder Vertex distance (mm)
Spectacle Rx -5.00 -3.50 12
(minus cyl form)
Flat K Sphere Power Steep K Sph + Cyl
(corrected for VD) (corrected for VD)
45.00 -4.72 49.00 -7.71
Fit factor* 0.25 -0.75
CL Rx Flat BCR (D.) Power Steep BCR (D.) Power
45.25 -4.97 48.25 -6.96
Flat BCR (mm) steep BCR (mm)
7.46 6.99
*if lens is fitted steeper than flat meridian put in dioptric value steeper as a plus value;
if fitted flatter than flat K put diopter value flatter as a minus value.
*for the steep meridian fit factor enter the diopter value flatter than the steep meridian
as a minus value.
29. Excel spreadsheet to calculate bitoric lens power using
a diagnostic lens and over-refraction.
CALCULATION OF POWER FOR BITORIC RGP LENSES
USING DIAGNOSTIC LENSES AND OVER-REFRACTION
Enter the requested values in the blank (white) cells.
Flat meridian Steep meridian
Diagnostic Lens BC (D.) 44.00 44.00
Power of diagnostic lens* -3.00 -3.00 *enter total power in each meridian
Over-refraction** -1.00 -3.00 vertex distance (mm) 12
Over-refraction vertexed -0.99 -2.90
Base curve ordering (D.) 43.00 46.00
**total power of over-refraction in each meridian
CL Rx Flat Meridian power Flat meridian BC Steep meridian power Steep meridian BC
-2.99 43.00 -7.90 46.00
This spreadsheet program can be downloaded from:
http://www.opt.indiana.edu/lowther/index.htm
31. SUMMARY OF FITTING TORIC BASE CURVE RGP LENSES
Using K-readings and Spectacle Rx
1. Do exam and obtain K-readings and spectacle Rx
2. Determine lens diameter and optical zone
3. Select base curve: flat K and ¾ corneal toricity in lens.
4. Calculate lens power
a) calculate using power crosses
b) Use spreadsheet program
c) Mandell-Moore form
5. Order lens
Can use spherical diagnostic lens and do over-refraction.
From this calculate power needed in bitoric lens as a check
on the power required.
32. SUMMARY OF FITTING TORIC BASE CURVE RGP LENSES
Using bitoric diagnostic lens:
1. Do exam and obtain K-readings and spectacle Rx
2. Determine lens diameter and optical zone
3. Select base curve: flat K and ¾ corneal toricity in
lens
4. Evaluate fluorescein pattern-change diagnostic lens if
necessary to get best fit.
5. Do an over-refraction
6. Calculate lens power
7. Order lens