The Cathedral Eye Clinic

Dry Eyes are one of the most common ocular surface problems seen by ophthalmologists today with over 4 million people in the UK estimated to suffer from this condition.

It occurs when an individual does not produce enough tears or the composition of the tears is abnormal and cannot adequately cover the surface of the eye. The tear film is an essential part for ensuring the overall health of the ocular surface. It cleanses, lubricates, and nourishes the surface of the eye as well as protecting it against infection. Both the quality and quantity of the tears must be maintained within certain levels to ensure a healthy and clear refractive surface essential for good vision.

Symptoms

There are many symptoms associated with dry eye, the most common being:

• Grittiness or Sandy Feeling in the eyes
• Burning or Stinging sensation
• Itching and Scratchiness
• Soreness or Painful
• Foreign body sensation
• A feeling of Dryness
• Sensitivity to light

There are many different causes of dry eye. Some of the most common causes are shown here.

• Adverse Environmental Conditions : Air conditioning, low humidity in aeroplanes, central heating, car heaters, windy weather and smoky environments can all cause tears to evaporate more quickly resulting in a feeling of irritated eyes.
• Contact Lenses, Watching TV and looking at a Computer Screen for long periods of time can all result in a decrease in your rate of blinking which adversely affects your tearfilm.
• Hormones: Many women find that they experience dry eye symptoms on reaching the menopause.
• Medications such as anti-depressants and anti-histamines
• Age :The incidence of dry eye increases with age due to the natural aging process.
• Blepharitis – Bacteria and inflammation of the lids can restrict the proper functioning of the meibomian glands that are involved in producing lipids essential for a healthy tear film.
• Sjögren’s Syndrome :This is an autoimmune disorder that affects the lacrimal gland that is responsible for normal tear production.
• Other causes of dry eye include chronic allergies and conditions such as rheumatoid arthritis and lupus.

Diagnosis

The criterion for the accurate diagnosis of Dry Eye can be complicated and is often controversial amongst clinicians and researchers. This is because there is a wide variety of ocular surface assessments and clinical diagnostic tests currently available some of which do not always correlate with patient symptoms.

Some of the most common tests are:

• Dry Eye Questionnaire :this helps the ophthalmologist to assess patient symptoms and correlate them with signs of tear film disorders. Free online dry eye questionnaire to find out immediately if you may have dry eye.
• Physical Examination :The ophthalmologist will perform an assessment of the whole surface of the eye looking for signs of inflammation and meibomian gland disorders, which are often connected to tear film abnormalities.
• Phenol Red Thread Test :A small thread which changes colour from yellow to red when wet is placed into the lower conjunctival sac for 15 seconds to measure tear volume.
• Schirmer Test :this is a simple test to measure tear production and is performed by placing a filter paper strip over lower eyelid for 5 minutes. The amount of tears absorbed into the paper in this time indicates whether there are enough or too little tears being produced.
• Assessment of Tear Film Stability :Evaluation of the stability of the tear film is considered to be one of the most useful tools for the diagnosis of dry eye since an unstable and unrefreshed tear film is one of the most indicative signs of the presence of dry eye. The measurement of tear stability can be carried out by measuring the time in seconds between one complete blink and the first appearance of a discontinuity or dry spot in the fluorescein stained tear film. Many ophthalmologists consider the assessment of tear film stability by use of fluorescein to be the most important clinical diagnostic test available today.
• Impression cytology to look at goblet cell numbers in the conjunctiva: The ophthalmologist takes a small sample of cells from the surface of the eye using a small piece of specialised filter paper. These cells that are collected on the paper can stained so the number of goblet cells can be counted. People with only a small number or even none of these cells usually have Dry Eye.

Treatments

Management of dry eye is usually a combination of treatments and lifestyle changes that are tailored to the needs of an individual patient. Professor Moore believes that there are two main goals when addressing the treatment of his dry eye patients. “My primary aim is to alleviate symptomatic discomfort and then secondary to prevent or reverse complications and further ocular surface damage that may cause a deterioration of their vision.”

• Artificial Tears :“While many find rapid relief using artificial tears, often this reprieve short-lived with the patient having to use them up to eight to ten times per day,” explains Dr Moore. Indeed some artificial tears contain preservatives that may in fact exacerbate the problem and therefore it is often recommended that non-preservative tear supplements should be the first choice.
• Warm Compresses: Some patients’ symptoms can be alleviated by applying warm moist compresses to the skin of closed eyelids which allows easier release of lipids from the meibomian glands.
• Surgery : blocking of the tear duct with a permanent or semi-permanent plug (usually silicone, collagen or plastic) often helps those with severe dry eye by preventing the drainage of the tears.

Cataracts result in loss of transparency of the natural clear lens which results in patients finding it increasingly difficult to see. The first sign may be an increased reliance upon reading glasses. These can be removed through a simple quick operation. A choice exists of types of intraocular lenses available to replace the cataract with new types of intraocular lenses.

Intraocular Lens Procedures

An intraocular surgical procedure is used to treat patients who are either not suitable for laser surgery because their refractive error is too great or they have a corneal problem. The two principal types of intraocular procedure include phakic IOL implantation or clear lens extraction.

• Phakic IOLs gain their name on the basis that a person retains their own lens within the eye and these lenses are additional. They can be thought of as implantable contact lenses.
• Clear Lens Extraction is particularly suitable for people over the age of 40 where their natural lens is becoming less flexible and unable to change shape and focus. The procedure is reserved for patients with large refractive errors who are not suitable for laser refractive surgery

Cataract results

In 2007 alone Cathedral Eye Clinic has currently carried out more than 900 cataract operations. The results of these surgeries are constantly being audited with the aim to ensure that results are of the highest standard possible and where possible to fine tune and constantly improve these results.

Postoperative overall visual results of cataract surgery carried out by The Cathedral Eye Clinic demonstrated that greater than 90% of patients resulted in a best corrected vision of 6/12 or better. This compares well with similar studies carried out in the UK with the final visual acuity in some patients very much related to the degree of co-morbidity.

The first column represents the visual results published from the most commonly reported national UK study of cataract results called the National cataract survey published by Desai in the BJO, this represents the visual results from 15787 patients. The second column represents the visual results from 400 consecutive cataract patients treated in 2007 by the Cathedral Eye Clinic in conjunction with 352 medical consulting.

Best Corrected Visual Acuity Post surgery:

UK NCS

Cathedral Eye Clinic / 352
All patients 86% >/= 6/12
92.5%>/=6/12

Desai; P, Minassian DC & Reidy A. National cataract surgery survey 1997−8: a report of the results of the clinical outcomes. Br J Ophthalmol 1999; 83: 1336−1340.

Age related macular degeneration is the leading cause of visual loss in the over 65s in the developed world. As the elderly population increases the incidence of this disease consequently also increases. Various different treatments have been evolving to manage this condition over the years.

• Laser
• Photodynamic therapy
• Surgery
• Anti-VEGF therapies
• Possible nutrient prophylaxis (Age Related Eye Disease Study)

Risk Factors:

• Age
• Smoking
• Genetics
• Gender
• Nutrient status (possibly)

When are treatments for ARMD useful?

Laser, Photodynamic therapy, Surgery and anti-VEGF therapies are only useful when choroidal neovascularisation has occurred. The process of choroidal neovascularisation occurs when blood vessels accompanied by inflammatory cells grow under and through the retinal pigment epithelium to disrupt and damage the delicate overlying retinal cells.

The tissue invasion is as described above not only new blood vessels but also inflammatory cells. Specific treatments to target either or both of these components are being actively researched. Anti-VEGF treatments principally target the vascular components. Injectable steroids such as triamcinolone target principally the inflammatory cell component This has been termed a two component target therapeutic model for CNV

(Gasparini G, et al. (2005)J Clin Oncol 23:1295-1311)

Cathedral Eye Clinic are currently using both anti-VEGF, intraocular steroids and laser photocoagulation as part of the therapeutic modalities designed to manage these conditions.

Diabetes is very common, affecting approximately 1 in 25 patients in the developed world. In the UK up to 9% of the whole NHS budget is used to treat diabetes and its related complications.

The condition can start in childhood or later in life. It can affect many different parts of the body, but particularly the eye.

How does diabetes affect the eye?

Diabetes can affect the eye in various ways. The most serious effects however are through problems in the retina. This problem is called diabetic retinopathy.

Diabetic retinopathy occurs as a consequence of diabetes and can result in loss of vision either through leaky blood vessels causing swelling of the retina or by causing the production of abnormal blood vessels which result in bleeding within the eye and scaring of the retina.

Screening is essential to detect vision threatening stages prior to loss of vision.

Having diabetes does not mean that a person will have eye problems, but it is important that regular eye examinations are carried out to ensure that any potential problems are diagnosed early. Sight loss from diabetes can usually be prevented if retinopathy is diagnosed and treated early. After diagnosis the condition can be graded by a person’s eye specialist depending on its severity.

Treatment

The most important aspect of management of diabetes is to ensure that good cooperation exists between each patient and the team of health professionals who are involved in managing their care. The general practitioner is key to proper management of all systemic medical factors. However, the ophthalmologist as a diabetic retinopathy screener in addition to directly managing retinal problems should provide support to the GP by helping to communicate the value of good systemic medical management. Strategies for treatment combine optimization of systemic risk factors such as blood glucose control, blood pressure management, reducing blood lipid levels.

Evidence for the value of controlling these factors includes:

Glycaemic Control:- Diabetes Control and Complications Trial (DCCT) demonstrated a 26% reduction in the risk of developing macular oedema where there was intensive insulin treatment

Blood Pressure Control:- UK Prospective Diabetes Study (UKPDS) reported a 47% reduction in loss of vision from macular oedema in Type II diabetics where there was tight blood pressure control

Blood Lipid Control:- The DCCT and the ETDRS studies have demonstrated positive correlations between lipid profiles and the development of macular oedema in patients with type I Diabetes.

Smoking:- This is a well recognized risk factor for diabetic micro- and macrovascular problems. No diabetic should smoke.

Local Ophthalmic Treatment

The Cathedral Eye Clinic follows the Early Treatment of Diabetic Retinopathy Study (ETDRS) guidelines when managing diabetics with laser photocoagulation. This study sponsored by the US National Eye Institute has shown that early laser intervention when clinically significant macular oedema is present can reduce the risk of moderate visual loss by 50%.

In addition to the ETDRS study guidelines the institute advocates using larger spot sizes with longer durations and lower energy profiles. This is in response to more recent studies demonstrating effectiveness of this technique while minimising any side-effects of the laser treatment. (Roider J et al, 2000, BJO 84(1):40-47)