A STUDY ON CORNEAL THICKNESS AND ENDOTHELIAL CELL COUNT IN DIABETES MELLITUS AND NON – DIABETES MELLITUS PATIENTS
Brief resume of intended work
6.1 Need for study
Diabetes Mellitus is a major health problem all over the globe. It is estimated that by the year 2025 5.4 % of the population will be affected by Diabetes. The number of adults with diabetes in the world will rise from 135 million in 1995 to 300 million in the year 2025.1
Diabetes Mellitus affects several structural changes in the eye including cornea. Corneal thickness is increased in Diabetic patients compared to healthy controls. In adults increased corneal thickness may have very real implications in the diagnosis and management of glaucoma. The influence of corneal thickness on the measured intra ocular pressure with thicker corneas having artificially high readings. Close attention should be paid to pachymetry in the management glaucoma in diabetic patients2
Diabetes mellitus causes alterations in stromal collagen fibrils and proteoglycans.The loss in endothelial cells compromises the endothelium’s capacity to maintain stromal homeostasis via ATP – dependant pumping of water and ions. This compromised endothelium leads to stromal thickness and results in decreased corneal transparency.2
A detailed study helps to know the functionality of the endothelium before conducting the cataract surgery, Pan Retinal Photocoagulation, and long term use of contact lenses in Diabetes mellitus patients.
6.2 Review of literature:
N.Busted et.al. In their study “clinical observations on the corneal thickness and the corneal endothelium in diabetes mellitus” found that the augmented corneal thickness in the diabetic subjects is tentatively interpreted as minimal corneal swelling. It seemed to be present very early in the disease and may thus be one of the earliest clinically detectable changes of the diabetic eye.3
Roszkowska AM et.al., in their study” Corneal endothelium evaluation in type I and type II diabetes mellitus” concluded that corneal endothelium in diabetics should still be considered as a tissue under continuous metabolic stress with consequent high vulnerability, especially in case of any external insult such as a surgical procedure.4
Saini JS et.al. in their study” In vivo assessment of corneal endothelial function in diabetes mellitus” found significantly lower corneal endothelial function in patients with non-insulin-dependent diabetes mellitus and thus suggests a higher potential to decompensate following any deleterious stress.5
de la Messeliere S et.al, In their study” corneal endothelium of diabetic patients. A study using specular microscopy” concluded that diabetes alters but does not significantly destroy the corneal endothelial cell. This result must be taken into account in corneal surgery as the diabetic cornea is a high risk cornea.6
MM Choo et.al., in their study” Corneal changes in type II diabetes mellitus in Malaysia” found Type II diabetes causes a significant alteration in the state of the cornea including reduction in endothelial cell density and increased pleomorphism and polymegathism. Central corneal thickness is unaffected.7
Siribunkum J, et.al. In study of” Corneal abnormalities in diabetes” Found that the diabetic corneas tended to be thicker and had more pleomorphism and polymegathism, though this was not statistically significant. Duration of diabetes mellitus correlated significantly with these corneal changes. This suggests that corneal changes should be evaluated and confirmed before intraocular surgery in chronic diabetic patients.8
Shenoy Ret.al., in their study of” corneal endothelium in patients with diabetes mellitus: a historical cohort study” found corneal endothelium in diabetic patients seems to be compromised. Evaluation of corneal endothelium should be part of protocol for eye care of diabetic patients.9
JS Lee et.al., in their study of “Differences in corneal thickness and corneal endothelium related to duration in Diabetes” found Those patients with diabetic duration of over 10 years have more corneal morphological abnormalities, especially the coefficient of variation in cell size, compared with the normal subjects. The central corneal thickness was significantly correlated with diabetic duration after controlling for age.10
Sudhir RR et.al., in their study of “Changes in the corneal endothelial cell density and morphology in patients with type 2 diabetes mellitus: a population-based study Sankara Nethralaya Diabetic Retinopathy and Molecular Genetics Study (SN-DREAMS, Report 23)” Found that from a large population-based sample, support the earlier theories of lower endothelial cell counts among subjects with type 2 diabetes mellitus in comparison with non-diabetic controls.11
6.3.Aims and Objectives of the study : To study and document the corneal thickness and endothelial cell count in Diabetes mellitus patients of type 1 & type 2 with age matched control of non – Diabetes mellitus patients
Materials and method
7.1 Source of the data: Diabetes mellitus patients attending Minto ophthalmic hospital & regional ophthalmic centre Bangalore attached to Bangalore Medical College and Research Institute, Bangalore.
7.2. Method of collection of data :
Study design: Hospital based interventional prospective study.
Study period : October 2013 to May 2015
Place of study: Minto Ophthalmic hospital attached to Bangalore Medical college and research institute, Bangalore.
Sample size : 100 patients of Diabetic type 1 & type 2 and 100 non- diabetic patients
Inclusion criteria: Patients with diabetes of type 1 and type 2 who are already diagnosed and on treatment.
G. Methodology: Diabetes Mellitus patients attending Minto Ophthalmic Hospital who full fill the inclusion & exclusion criteria will be selected by simple random sampling and complete timed ophthalmic evaluation will be performed. Specular Microscopy will be performed on all patients for endothelial cell count assessment .All patients will undergo corneal thickness measurement by Ultrasonic Pachymeter. The evaluation of the corneal thickness and endothelial cell count will be documented. The readings will be correlated and analyzed.
H.Statistical analysis : depending upon the data available appropriate statistical test will be applied and analysis will be done
7.3. Does the study require any investigation of interventions to be conducted on patients or other humans or animals? if so ,please describe briefly
Yes. It involves following investigations and interventions on human subjects
7.4 Has the ethical clearance been obtained from institution in case of 7.3
List of reference
King H, Aubert RE, Herman WH. Global burden of diabetes, 1995-2025: prevalence, numerical estimates, and projections. Diabetes Care. 1998 Sep; 21(9):1414-31.
Metabolic Disorders of cornea Stephen.G.odaibo,nikisha.q.richards,Robert .A Copel;and Jr, Copeland and afshari’s Principles and practice of cornea Jaypee – Highlights ,2013 volume 1 622 – 624
N Busted, T Olsen and O Schmitz Clinical observation on the corneal thickness and the corneal endothelium in diabetes mellitus Br j ophthalmol 1981 65:687 -690
Roszkowska AM, Tringali CG, Colosi P, Squeri CA, Ferreri G. Corneal endothelium evaluation in type I and type II diabetes mellitus. Ophthalmologica. 1999; 213(4):258-61.
Saini JS, Mittal S. In vivo assessment of corneal endothelial function in diabetes mellitus. Arch Ophthalmol. 1996 Jun; 114(6):649-53.
de la Messeliere S, Renard G. The corneal endothelium of diabetic patients. A study using specular microscopy J Fr Ophtalmol. 1987;10(11):647-55
MM Choo, K Prakash, A Samsudin, T Soong, N Ramli, and AJ KadirCorneal changes in type II diabetes mellitus in Malaysia Eur J Ophthalmol. 2009 May-Jun; 19(3):369-75.
Siribunkum J, Kosrirukvongs P, Singalavanija A. Corneal abnormalities in diabetes. J Med Assoc Thai. 2001 Aug;84(8):1075-83
Shenoy R, Khandekar R, Bialasiewicz A, Al Muniri A. Corneal endothelium in patients with diabetes mellitus: a historical cohort study. Eur J Ophthalmol. 2009 May-Jun; 19(3):369-75.
Lee JS, Oum BS, Choi HY, Lee JE, Cho BM. Differences in corneal thickness and corneal endothelium related to duration in diabetes. Eye (Lond). 2006 Mar; 20(3):315-8.
Sudhir RR, Raman R, Sharma T. Changes in the corneal endothelial cell density and morphology in patients with type 2 diabetes mellitus: a population-based study, Sankara Nethralaya Diabetic Retinopathy and Molecular Genetics Study (SN-DREAMS, Report 23). Cornea. 2012 Oct; 31(10):1119-22.
Signature of the candidate
Remarks of the Guide : Evaluation of corneal endothelium and thickness by Specular microscopy and usg will provide more information regarding the state of the cornea ,though clinically it might appear translucent .Identification of potential risk factors viz., low endothelial count ,endothelial dimorphism and corneal thickness etc., provides us information and helps us to plan appropriate surgical procedure with improvised techniques viz., use of cohesive viscoelastics for intraocular surgery
I, Mr/Mrs/Ms ___________________________________exercising my own free will power of choice, hereby give consent for myself as an subject in the evaluation of corneal thickness and endothelial cell count conducted under the guidance of Dr.G.Nagraju by Dr.B.J.Nagesh at minto ophthalmic hospital attached to Bangalore Medical College and Research Institute ,Bangalore
The attending doctors have informed me to my satisfaction and in the language best understood by me, the purpose of this study, the materials to be used during the course of this study as well as the side effects / complications associated with methods / tools to be used
I shall not hold doctors or the staff responsible for any untoward consequences.
I am also aware of my right to opt out of the study without prejudice to further treatment at any time during the course of the study without having to give reasons to do so.
Signature of the attending doctor: Signature/ Left thumb