Has the quantity of fluidics used during phacoemulsification an

effect on the corneal endothelium?

Author: Adriana Stănilă, D.M. Stănilă, Elena Mihai, N.G. Sârbu, A.L. Stupariu

University Lucian Blaga Faculty of Medicine “ Victor Papilian “ Sibiu

Clinical Emergency Hospital , Sibiu

Research Centre of Ocular Surface Diseases

Introduction

The cataract is one of the most frequent ocularsurgical disease. The cataract means the opacifation of the lens. The removal of the opacified lens is madeusualy through the phacoemulsificationtechnique. The removal of the lens presumes his replacement with an artificial lens

This procedure can have different effects on the endoocular structures and especially on the cornea ( endothelial cells layer)

The corneal endothelium is a single layer of cells

Its role is essential in maintaining the integrity of the cornea. Its cells can’t regenarate. Starting with the second decade of life the density of the cells decrease from 3000 – 4000 cells/mm2 to 2500 – 2700 cells/mm2 in the eight decade of life. The loss of cells with the age causes the expansion of the neighbor cells in order to fill the empty spaces.

Corneal transparency is controlled by the active endothelial ionic pumps, which maintain a low level of stromal hydration

When the endothelial cell count drops below 600 to 800 cells/mm2,cornealdecompensation, and corneal edema occuras a result of the compromised pump function

The aim of the study

The purpose is to show the effects of the cataract operation through the phacoemulsification technique on the corneal endothelium related with the quantity of fluidics used.

Material and Methods

Our study is based on 40 patients which where operated through this type of surgery in the clinic of ophthalmology of the Sibiu hospital. All cases where age related cataract with the index of nuclear sclerosis up to third degree.

Exclusion criteria where the ocular diseases , systemic diseases , corneal pachymetry greater than 0,60mm and the preoperative endothelial cells count less than 1800.

The pachymetry presumes the measuring of the cornea which is an indicator of the integrity of the corneal endothelium ( normal thickness in the central area is between 0,49 – 0,56 mm )

All the surgeries where performed by the same surgeon and by the same technique.

The surgical procedure topical anaesthesia , with tetracaine 0,5 % administrated 10 minutes

before surgery the clear corneal microincision (2,2mm) using OVD (ophthalmic

viscosurgical device) cohesive and dispersive phacoemulsification with the Infinity machine. Implantation of foldable artificial lens

The number of the endothelial cells and the pachymetry of the cornea where performed through specullar microscopy in the day before and after 7-14 days after surgery

Results and Discussions

We have found a statistic value (p<0,05), concerning the loss of endothelial cells count and change of corneal thickness. At values over 120 cc we found no statistical value.

Variabila Frecventa Medie Deviatie standard p – test t pereche

Preoperator 40 2106,82 262,03 Densitate

Postoperator 40 1794,70 375,85 0,000**

Preoperator 40 593,98 43,85 Grosime

Postoperator 40 609,10 49,15 0,009**

Cantitate – 45 ÷ 60

Preoperator 14 2134,79 181,99 Densitate

Postoperator 14 1995,07 267,59 0,035*

Preoperator 14 594,21 27,80 Grosime

Postoperator 14 608,50 44,26 0,167

Cantitate – 61 ÷ 80

Preoperator 16 2151,50 288,36 Densitate

Postoperator 16 1722,13 397,04 0,000**

Preoperator 16 597,25 55,46 Grosime

Postoperator 16 614,50 54,77 0,061*

Cantitate – 81 ÷ 120

Preoperator 5 2045,20 348,27 Densitate

Postoperator 5 1618,40 311,32 0,010*

Preoperator 5 582,20 57,67 Grosime

Postoperator 5 614,00 57,92 0,046*

Cantitate – >120

Preoperator 5 1947,20 285,26 Densitate

Postoperator 5 1642,20 476,48 0,102

Preoperator 5 594,60 34,05 Grosime

Postoperator 5 588,60 43,72 0,744

Results

0

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1 4 7 10 13 16 19 22 25 28 31 34 37

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Corneal endothelial cells density

Densitate preoperator

Densitate postoperator

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1 4 7 10 13 16 19 22 25 28 31 34 37

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Grosime corneanapreoperator

Grosime corneanapostoperator

R² = 0.0471

-400

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The endothelial cells loss related with the fluidics

The correlation coefficient between the quantity of fluidics used and the cells endothelial loss has a low value

R²=0,0471

The risk of endothelial cells loss corelated with the fluidcs dinamic is low.

Until recently it was belived that the human cornea had an average value of 550 microns, having 5 layers: epithelium, Bowman membrane, stroma, Descemet membrane and endothelium, Recently the clinical experienced from the corneal transplantation has lead to the discovery of new layer, the 6th. This discovery was made by Harminder Dua from the University of Nottingham.

The layer is between the stroma and the Descememt membrane. This layer has been highlated by injecting air between the layers of the cornea and has been confirmed by electronic microscopy.

Even if it is very thin (only 15 microns), Dua’s layer is very resistant and is able to resist to pressusre up to 1,5 – 2 bars. In the present it is belived that different corneal edema is caused by discontinuities in Dua’ s layer caused by different factors.

Conclusions

The injury of the cornea during phacoemulsification is multifactorial.

The loss of endothelial cells related with fluidics is not significant

The phacoemulsification technique through microincision and the usage of OVD is very safe for the cornea.

References

A. Stanila , Cristalinul 2001 ( pg. 164 – 175) B. K. Nayak and Elesh Kumar Jain , Comparison of corneal

endothelial cell loss during phacoemulsification – Indian Journal of ophthalmology ; Sept 24 2008

Steve A. Arshinoff , Cataract surgery is unsafe without the protection of OVD’s – Cataract and refractive surgery today ; april2010 vol.5 nr. 4 (pg. 21-26)

Lara C. Pullen, Newly Identified Dua's Layer in Cornea May Improve Surgeries. Medscape Medical News, Jun 2013

Dua H, Faraj LA, Said DG, Gray T, Lowe J. Human Corneal Anatomy Redefined: A Novel Pre-Descemet's Layer (Dua's Layer). Symposium on Evolving Techniques in Corneal Surgery – Layer by Layer and EuCornea Annual Congress, Milan, 2012.

Thank You

Thank You !