Mr Akash Raj MBBS & MD (AIIMS), MRCS, DRCOphth, FRCS, FRCOphth, PG Dip (Distinction) Consultant Ophthalmologist, Glaucoma specialist and Cataract surgeon, Birmingham, Dudley, Ashby De La Zouch, Midlands, UK
Mr Akash Raj MBBS & MD (AIIMS), MRCS, DRCOphth, FRCS, FRCOphth, PG Dip (Distinction)Consultant Ophthalmologist, Glaucoma specialist and Cataract surgeon, Birmingham, Dudley, Ashby De La Zouch, Midlands, UK 

Basis of Eye Pressure & Aqueous humour circulation



 

The eye pressure (Intraocular Pressure=IOP) is intricately related to the production and the drainage of Aqueous humour and it is essential to normal functioning of the eye. Aqueous humour is a clear fluid and mainly composed of water (98%), amino acids, electrolytes, ascorbic acid, glucose, immunoglobulins and glutathione.

 

The main functions of Aqueous humour involves in maintaining eye pressure, inflating the eye ball and maintaining the shape and size of the eye, providing nutrition (e.g. amino acids and glucose) for the eye and to defend against pathogens.

 

 

Production and drainage of Aqueous Humour

Aqueous humour is produced by the ciliary processes (about 70 in total per eye) of the ciliary body specifically the non-pigmented epithelium of the ciliary body (pars plicata)) and is secreted into the posterior chamber of the eye situated behind the iris (the coloured part of the eye). It then flows forward through the pupil and into the anterior chamber of the eye (the space in front of the iris & behind the cornea). It then drains out of the eye via the trabecular meshwork and into the Schlemm’s canal and finally via 25-30 collector channels (aqueous veins) to the episcleral veins. 

In normal circumstances there is equilibrium where Aqueous humour is continually produced by the ciliary processes and this rate of production is balanced by an equal rate of aqueous humour drainage. Small variations in the production or outflow of aqueous humour may have a large influence on the eye pressure.

The greatest resistance to aqueous flow is provided by the trabecular meshwork, and the inner wall of the Schlemm’s canal (diameter of 190-350 Micrometers) and this is where most of the aqueous outflow occurs. The pressure of Aqueous Humour is normally 15 mmHg (0.6 in Hg) above atmospheric pressure, so if a needle is introduced surgically into the eye the fluid flows out easily.

The normal eye pressure is in the range of 10-21mm Mercury and vast majority of people will have their eye pressure in the middle of this range. Very high eye pressure as well as very low eye pressure (under 6mm Mercury and called Hypotony) are detrimental to the normal functioning of the eye and can impair vision. Higher is the level of eye pressure greater is the risk of Glaucoma. The raised pressure in the eye is caused by the breakdown of the equilibrium between the production of and the drainage of the aqueous humour. It may be as a result of either increased production or decreased outflow of aqueous humour. The peripheral part of the anterior chamber, between the cornea and the iris region is referred to as the filtration angle (at the junction of the white and black of the eye but inside the eye). A delicate connective tissue web work, the trabecular meshwork through which the aqueous humour drain out of the eye. The production of the aqueous humour is a constant process; and its removal is vitally important: the balance between production and drainage determines the eye pressure.

Aqueous humour is produced at an average rate of 2.0–3.0 µL/min, and its composition is altered as it flows from the posterior chamber, through the pupil, and into the anterior chamber. The volume of the Anterior Chamber is 250 microliters (µL) and the volume of the Posterior Chamber is 60 microliters (µL), therefore the turnover of aqueous humour is 1.5 - 2 hours.  

 

Aqueous humour formation is known to decrease during sleep (suppression of 45±20%), advancing age (decrease of 2% per decade), uveitis, Retinal detachment, and ciliochoroidal detachment. The rate of aqueous humour formation is relatively pressure-insensitive.

 

Please feel free to discuss any of the above points with Mr Raj if you would like further information.

Private & NHS patients

How to see Mr Raj

For private patients & referrals

 

Mr Akash Raj 

Consultant Ophthalmologist, Glaucoma specialist & Cataract surgeon

 

West Midland Hospital

(Alternate Thursday AM)

Colman Hill

Halesowen

West Midlands

B63 2AH

 

Appointments:

01384 632 640

 

Private Secretary: Liz Carter : 01384 632 636 

                               Fax:     01384 632702

                                            FAO Liz Carter

 

 

 

Mr Akash Raj

Consultant Ophthalmologist, Glaucoma & Cataract specialist

 

BMI The Priory Hospital, Edgbaston

(Thursday PM)
Priory Rd, Birmingham, West Midlands
B5 7UG
 
Appointments:
0121 446 1638
(Consultation by appointment only)
 
Private Secretary:
Liz Carter
Direct Line: 01384632636 

 



 

 

 

 

For NHS Referrals through GP/Opticians

 

Mr Akash Raj

Consultant Ophthalmologist (Glaucoma Lead)

 

Russells Hall Hospital

Pensnett Road

Dudley

West Midlands

DY1 2HQ

 

Phone: 01384456111

Extn. 5815 (NHS Secretary: Lyn Eaton)

 

Fax:     01384244880

            FAO  Lyn Eaton

 



Mr Raj's private consultation times

Telephone consultations @ mutually convenient times. Please see options above.

 



Thursdays (alternate) 9am to 12 Noon @ West Midland Hospital, Colman Hill, Halesowen.

 

 

 

EveryThursday (2 pm - 4 pm) @   The Priory Hospital, Edgbaston(With prior appointments only)

 

 

 

 

Ashby Eye Clinic: 

 

Every Friday at Dr Dawes's Surgery. Please call the surgery for appointments.

The Surgery, Ashby
30 North Street
Ashby-de-la-zouch
Leicestershire, LE65 1HS
Tel: 01530 417415

Please lookout for timings.

http://www.thesurgerynorthstreetashby.nhs.uk

 

 

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