For optometry students Ophthalmic instrument

1. 𝗞𝗘𝗥𝗔𝗧𝗢𝗠𝗘𝗧𝗘𝗥
𝗣𝗿𝗲𝘀𝗲𝗻𝘁𝗲𝗱 𝗯𝘆 - 𝗠𝘂𝘀𝗵𝗮𝗵𝗶𝗱 𝗥𝗮𝘇𝗮
𝗕.𝗼𝗽𝘁𝗼𝗺
𝗥𝗮𝗺𝗮 𝗠𝗲𝗱𝗶𝗰𝗮𝗹 𝗖𝗼𝗹𝗹𝗲𝗴𝗲 𝗸𝗮𝗻𝗽𝘂𝗿

3. 𝗜𝗻𝘁𝗿𝗼𝗱𝘂𝗰𝘁𝗶𝗼𝗻
• The radii of the curvature of the cornea
• The presence of any corneal distortion
• The degree of corneal astigmatism
• Keratometry is essential in the fitting of contact lens
• The determination of appropriate Intra ocular lens Implant power for
Pt. Undergoing cataract surgery
• Evaluating the Pt. With Keratoconus
• The direction of principal meridians of of the eye, determining
whether the astigmatism is with-the-rule Or against- the- rule a
Factor in contact lens fitting

4. 𝗣𝗔𝗥𝗧𝗦 𝗢𝗙 𝗞𝗘𝗥𝗔𝗧𝗢𝗠𝗘𝗧𝗘𝗥

5. 𝗢𝗽𝘁𝗶𝗰𝗮𝗹 𝗣𝗿𝗶𝗻𝗰𝗶𝗽𝗮𝗹
• Cornea is Convex refracting surface
• Anterior surface of Cornea – Convex mirror
• From image size formed by anterior surface of the cornea ( 1st
purkinje image) – radius of curvature of cornea can be calculated.

6. 𝗢𝗽𝘁𝗶𝗰𝘀

7. 𝗧𝗬𝗣𝗘𝗦 𝗢𝗙 𝗞𝗘𝗥𝗔𝗧𝗢𝗠𝗘𝗧𝗘𝗥
There are two types of keratometer which is given below –
1- Javal- Schiotz model keratometer
2- Bausch & Lomb keratometer
1- Javal- Schiotz model keratometer
It is two 𝙿𝙾𝚂𝙸𝚃𝙸𝙾𝙽 𝙸𝙽𝚂𝚃𝚁𝚄𝙼𝙴𝙽𝚃 which uses a fixed image
and doubling size adjustable object size to determine the radius
Of curvature of the refractive surface.

8. ᴊᴀᴠᴀʟ- sᴄʜɪᴏᴛᴢ ᴍᴏᴅᴇʟ ᴋᴇʀᴀᴛᴏᴍᴇᴛᴇʀ

9. 𝟸- Bausch & Lomb keratometer
One position Keratometer - it measures two meridians at the same
time.
It contains two prism.

10. 𝗣𝗿𝗼𝗰𝗲𝗱𝘂𝗿𝗲
𝗦𝘁𝗲𝗽 𝟭 - 𝙴𝚢𝚎𝚙𝚒𝚎𝚌𝚎 𝚊𝚍𝚓𝚞𝚜𝚝𝚖𝚎𝚗𝚝
Turn the eyepiece counter clockwise ( anti clockwise) place
a white sheet of a paper in
front of the telescope part.

11. 𝗦𝘁𝗲𝗽 𝟮 - 𝚃𝚞𝚛𝚗 𝚝𝚑𝚎 𝚎𝚢𝚎𝚙𝚒𝚎𝚌𝚎 𝚌𝚕𝚘𝚌𝚔𝚠𝚒𝚜𝚎
Until the specified target in the instrument become in sharp
focus.

12. 𝗦𝘁𝗲𝗽 𝟯 - 𝙰𝚍𝚓𝚞𝚜𝚝 𝚝𝚑𝚎 𝚑𝚒𝚐𝚑𝚝 𝚘𝚏 𝚝𝚑𝚎 𝚒𝚗𝚜𝚝𝚛𝚞𝚖𝚎𝚗𝚝
Align the outer a canthus of the pt. With the leveling sight
Sign

13. 𝗦𝘁𝗲𝗽 𝟰 - 𝙾𝚌𝚌𝚕𝚞𝚍𝚎 𝚝𝚑𝚎 𝚗𝚘𝚗 𝚝𝚎𝚜𝚝𝚎𝚍 𝚎𝚢𝚎
𝗦𝘁𝗲𝗽 𝟱 - 𝙰𝚜𝚔 𝚝𝚑𝚎 𝙿𝚝. 𝚃𝚘 𝚕𝚘𝚘𝚔 𝚊𝚝 𝚝𝚑𝚎 𝚌𝚎𝚗𝚝𝚎𝚛 𝚘𝚏 𝚝𝚑𝚎
𝚒𝚗𝚜𝚝𝚛𝚞𝚖𝚎𝚗𝚝 - If you are aligned, you can see the circles in the eye
The Pt. Can see the picture Of their eye
in the instrument.

14. 𝗦𝘁𝗲𝗽 𝟲 - 𝙰𝚍𝚓𝚞𝚜𝚝 𝚝𝚑𝚎 𝚏𝚘𝚌𝚞𝚜𝚒𝚗𝚐 𝚔𝚗𝚘𝚋
Such that you get a single image of the central circles

15. 𝗦𝘁𝗲𝗽 𝟳 – use the HORIZONTAL AlIGNMENT KNOB to bring the crosses
on each other.

16. 𝗦𝘁𝗲𝗽 𝟴 – use the VERTICAL ALIGNMENT KNOB to bring the crosses
on each other.

17. 𝗦𝘁𝗲𝗽 𝟵 - Read the value from the scale.