Each recommendation is rated based on the level of the evidence and the grades of recommendation. Definitions of the level of evidence (Ia-IV) and the grades of recommendations (A, B, C, and GPP) are defined at the end of the Major Recommendations field.
Introduction
C - Steroid eye drops are a frequently unrecognised cause of glaucoma. They should only be used as short-term therapy and intraocular pressure (IOP) monitoring is vital in such patients. (Grade C, Level IV)
This is especially so in those who have been applying them for more than 1 week, and includes steroid eye drops produced in combination with an antibiotic. Doctors must also ascertain that the patient has not already received similar therapy recently, before initiating a course of steroid eye drops. (Kersey & Broadway, 2005; Palmberg et al., 1975; Ng et al., 2000; Baratz & Hattenhauer, 1999)
Diagnosis of Glaucoma
The clinical features of the primary glaucomas are summarised in the table below. Please note that this list of signs and symptoms highlights key features and is not exhaustive. Please also refer to the photographs displayed in the original guideline document.
Table. Clinical Features of the Primary Glaucomas
|
Acute Angle Closure Glaucoma |
Primary Open Angle Glaucoma (POAG) & Chronic Angle Closure Glaucoma (CACG) |
SYMPTOMS |
|
- Painful red eye
- Blurring of vision, haloes
- Severe headache, nausea, and vomiting
- History of similar episodes in the past, which were aborted spontaneously with sleep
- The patient is frequently an elderly Chinese lady.
|
- Usually asymptomatic until advanced stages of the diseases
|
SIGNS |
Visual Acuity |
Decreased |
Normal / decreased in advanced stages |
Conjunctiva |
Injected |
Normal |
Cornea |
Hazy in symptomatic eye |
Clear |
Anterior Chamber |
Shallow in both eyes
Positive "eclipse sign" (nasal iris not illuminated by light shone from the temporal side, see Figure 1 on page 12 in the original guideline document) |
Deep in both eyes |
Gonioscopy |
Closed angles |
POAG - open angles
CACG - closed angles |
IOP |
Much higher than 21 mmHg and the eye may feel harder than fellow eye on digital palpation |
Usually higher than 21 mmHg |
Pupil |
Mid-dilated in symptomatic eye |
Relative Afferent Pupillary Defect (RAPD) if asymmetrical involvement |
Optic disc |
- May be difficult to examine due to hazy cornea
- Can be normal, hyperemic or cupped if there have been previous neglected attacks
|
- Vertical cup disc ratio >0.7 in a normal-sized disc
- Increase in cup disc ratio over time
- Asymmetry in cup disc ratio >0.2 between the 2 eyes
- Flame-shaped haemorrhages that extend across the disc margin (splinter haemorrhages)
- Focal loss of neuroretinal rim (notching)
|
Visual Field |
If glaucomatous nerve damage has been sustained, perimetry shows defects that are consistent with nerve fibre layer loss and these include:
- Temporal island
- Central island in advanced glaucoma
- Nasal step
- Paracentral or arcuate scotomas
|
Diagnostic Evaluation and Monitoring of Glaucoma
Baseline Tests
C - Patients suspected of having glaucoma should undergo the following three baseline tests (South-East Asian Glaucoma Interest Group [SEAGIG], 2004):
- IOP measurement by Goldmann Applanation Tonometry
- Disc documentation, preferably by photography
- Perimetry
(Grade C, Level IV)
B - The visual acuity and IOP are neither specific nor sensitive enough in themselves to be effective diagnostic or screening tools (Tielsch et al., 1991; Sommer et al., 1991). (Grade B, Level IIa)
GPP - IOP measurements should be combined with disc and visual field examination for greater sensitivity and specificity. (GPP)
Follow-Up
C - IOP measurement, disc appearance, and perimetry should be monitored during follow-up (SEAGIG, 2004). (Grade C, Level IV)
Treatment of Glaucoma
Goals of Therapy
A - IOP lowering is the only clinically effective approach in the management of glaucoma ("Comparison of glaucomatous progression," 1998; AGIS, 2000; Lichter et al., 2001; Heijl et al., 2002; Kass et al., 2002). (Grade A, Level Ia)
C - The target IOP is an estimate of the mean IOP achieved with treatment that is expected to prevent further optic nerve damage. An individualised target IOP range should be set for every glaucoma patient (SEAGIG, 2004). (Grade C, Level IV)
Pharmacological Treatment of Glaucoma
C - The first line of treatment in primary open angle glaucoma (POAG) is medical therapy and the choice of the drug depends on the target IOP, the safety profile of the drug, patient acceptance, and cost. (Grade C, Level IV)
A - The first line of treatment in primary angle closure glaucoma (PACG) is a laser iridotomy. A laser iridotomy is also required for the fellow eye. Supplemental medical therapy may also be required (Fleck, Wright, & Fairley, 1997; Lam et al., 2002). (Grade A, Level Ib)
C - In the emergency setting of acute angle closure glaucoma, additional systemic drugs like osmotic diuretics and oral/parenteral carbonic anhydrase inhibitors may be employed to rapidly reduce the IOP to avoid permanent, devastating nerve damage (SEAGIG, 2004). (Grade C, Level IV)
Laser Therapy for Glaucoma
A - In open angle glaucoma, laser trabeculoplasty may be used as an adjunct to medical therapy (The Advanced Glaucoma Intervention Study [AGIS], 1998; The Glaucoma Laser Trial [GLT], 1990). (Grade A, Level Ia)
Surgery for Glaucoma
C - Surgery is indicated in patients who fail or are unable to comply with medical therapy and may be combined with cataract removal for enhanced visual rehabilitation (SEAGIG, 2004). (Grade C, Level IV)
C - Trabeculectomy is the primary surgery of choice in medically uncontrolled glaucoma (Wilson, 1977; Watson & Barnett, 1975; Sherwood et al., 1993). (Grade C, Level IV)
GPP - Patients who have undergone glaucoma surgery should be advised that there is a lifelong need to be aware of symptoms of infection, which include blurring of vision, pain, redness, discharge, and swelling. (GPP)
Screening for Glaucoma
B - Routine population screening for glaucoma is not recommended at this stage. However, high-risk individuals such as first degree relatives of a glaucoma patient, age >65 years and elderly Chinese females (who are at risk of angle closure glaucoma) may be considered as target populations for case detection programmes (Tielsch et al., 1994; Rosenthal & Perkins, 1985; Foster, 2002; The U.S. Preventive Services Task Force [USPSTF] Recommendations for Glaucoma Screening, 2005). (Grade B, Level IIa, IIb)
Definitions:
Levels of Evidence
Level Ia: Evidence obtained from meta-analysis of randomised controlled trials
Level Ib: Evidence obtained from at least one randomised controlled trial
Level IIa: Evidence obtained from at least one well-designed controlled study without randomisation
Level IIb: Evidence obtained from at least one other type of well-designed quasi-experimental study
Level III: Evidence obtained from well-designed non-experimental descriptive studies, such as comparative studies, correlation studies, and case studies
Level IV: Evidence obtained from expert committee reports or opinions and/or clinical experiences of respected authorities
Grades of Recommendation
Grade A (evidence levels Ia, Ib): Requires at least one randomised controlled trial as part of the body of literature of overall good quality and consistency addressing the specific recommendation
Grade B (evidence levels IIa, IIb, III): Requires availability of well conducted clinical studies but no randomised clinical trials on the topic of recommendation
Grade C (evidence level IV): Requires evidence obtained from expert committee reports or opinions and/or clinical experiences of respected authorities. Indicates absence of directly applicable clinical studies of good quality
GPP (good practice points): Recommended best practice based on the clinical experience of the guideline development group.