Comparison of the safety and efficacy of the fixed combination of dorzolamide/timolol and the concomitant administration of dorzolamide and timolol: a clinical equivalence study

AIMS—To compare the tolerability and efficacy of a fixed combination solution of dorzolamide/timolol (Cosopt), administered twice daily with the concomitant administration of its components, dorzolamide (Trusopt) twice daily and timolol (Timoptic) twice daily.
METHODS—After a 2 week timolol run in, patients with open angle glaucoma or ocular hypertension were randomised (1:1) to receive treatment with either the dorzolamide/timolol combination solution twice daily (combination) or the dorzolamide solution twice daily plus timolol maleate solution twice daily (concomitant) for 3 months.
RESULTS—299 patients were entered and 290 patients completed the study. Compared with the timolol baseline, additional IOP lowering of 16% was observed at trough (hour 0) and 22% at peak (hour 2) at month 3 in both the concomitant and combination groups. The IOP lowering effects of the two treatment groups were clinically and statistically equivalent as demonstrated by the extremely small point differences (concomitant − combination) observed in this study−0.01 mm Hg at trough and 0.08 mm Hg at peak. The safety variables of the concomitant and combination groups were very similar. Both combination and concomitant therapy were well tolerated and few patients discontinued due to adverse effects.
CONCLUSIONS—The dorzolamide/timolol combination solution administered twice daily is equivalent in efficacy and has a similar safety profile to the concomitant administration of the components administered twice daily.

Keywords: dorzolamide; timolol; intraocular pressure; glaucoma; ocular hypertension     

Effects of latanoprost and dipivefrin, alone or combined, on intraocular pressure and on blood-aqueous barrier permeability

AIM—To investigate the effect on intraocular pressure (IOP) and aqueous flare of topical applications of latanoprost and dipivefrin alone or combined.
METHODS—22 patients with open angle glaucoma or ocular hypertension were included in a 4 week open label study. Median age was 68 years (range 50-79). They were allocated to either 2 weeks' treatment with once daily evening administration of latanoprost monotherapy (50 µg/ml) or twice daily dipivefrin monotherapy (1 mg/ml), followed by 2 weeks' combination therapy with both drugs.
RESULTS—Latanoprost alone reduced IOP from 19.3 (SD 1.4) to 14.8 (0.9) mm Hg (p<0.01). Addition of dipivefrin caused a further reduction to 12.4 (0.9) mm Hg (p<0.01 compared with latanoprost alone). In the group where the treatment started with dipivefrin IOP was reduced from 22.3 (1.2) to 18.4 (1.0) mm Hg (p<0.01) and with the combination to 14.9 (0.9) mm Hg (p<0.01). No change in aqueous flare was observed with either drug, alone or in combination. A slight increase in conjunctival hyperaemia was observed when the two drugs were combined.
CONCLUSIONS—Latanoprost and dipivefrin have an additive effect on IOP and no clinically significant effect on the permeability to proteins of the blood-aqueous barrier. This implies that the two drugs can be a useful combination for the treatment of glaucoma.

Keywords: aqueous flare; intraocular pressure; latanoprost; dipivefrin     

Prevalence and management of elevated intraocular pressure in patients with Graves' orbitopathy

AIMS—To investigate the prevalence and to discuss the necessity of treating elevated intraocular pressures (IOP) in patients with Graves' orbitopathy (GO). In addition, to study the effects of orbital decompression and extraocular muscle surgery on IOP.
METHODS—The records of consecutive patients with GO referred in a 5 year period were studied and those selected, in which glaucoma medication had been prescribed, or a diagnosis of primary open angle glaucoma (POAG) or of ocular hypertension (22 mm Hg) (OH) had been made. The necessity of treating these patients with glaucoma medication was questioned and the effects of corticosteroids, orbital decompression, and extraocular muscle surgery on the IOP were evaluated.
RESULTS—Of 482 patients with GO, 23 (4.8%) met the inclusion criteria. Four patients (0.8%) had POAG, four had elevated IOPs and visual field defects consistent with dysthyroid optic neuropathy, and 15 (3.1%) had only elevated IOPs. Five patients with OH showed a permanent drop of IOP after orbital decompression, two had a marked decrease of their IOP after recession of the inferior rectus muscle.
CONCLUSIONS—POAG has the same prevalence in the general Dutch population as in the GO subgroup. The combination of elevated IOPs and visual field defects in GO patients may be attributed to other mechanisms than obstructed aqueous outflow in the trabecular meshwork and should be treated accordingly. Orbital decompression and extraocular muscle surgery may lower the IOP in patients with GO.

Keywords: Graves' orbitopathy; primary open angle glaucoma; intraocular pressure     

Effects of short term increase of intraocular pressure on optic disc cupping

AIMS—To evaluate the effect of acute elevation of intraocular pressure (IOP) on optic disc cupping.
METHODS—10 emmetropic and 10 myopic volunteers were included in this study. The cup area (CA) and cup volume (CV) of the optic disc were determined with the Heidelberg retina tomograph (HRT). After baseline determinations, a suction cup was used to increase the intraocular pressure (IOP) to 20-25 mm Hg above the baseline and HRT images were obtained.
RESULTS—Baseline IOP was 13.5 (SD 1.3) mm Hg and 12.6 (2.6) mm Hg in the emmetropic and myopic groups, respectively. The IOP was elevated to 35.4 (3.3) mm Hg and 34.4 (2.5) mm Hg in the emmetropic and myopic groups, respectively. When compared with their baseline values, the cupping variables (CA and CV) were significantly increased (p<0.05) during the suction treatment in both emmetropic and myopic subjects.
CONCLUSION—There was a significant enlargement in the optic disc cupping during the artificial increment of intraocular pressure in both emmetropic and myopic eyes. In non-glaucomatous eyes the optic nerve head has a partially dynamic topography dependent upon the level of IOP.

Keywords: optic disc; intraocular pressure; compliance; glaucoma     

Brain natriuretic peptide: identification of a second natriuretic peptide in human aqueous humour

AIMS/BACKGROUND—To measure aqueous humour levels of brain natriuretic peptide (BNP) and atrial natriuretic peptide (ANP) in humans. To compare peptide levels in glaucomatous and control eyes to test the hypothesis that these peptides are increased in glaucoma. BNP and ANP are cyclic endopeptides whose principal biological effects are natriuresis and vasodilatation. Experimental glaucoma in animal models results in elevated aqueous ANP. Intravenous ANP administration in both animals and humans causes lowering of intraocular pressure (IOP). There are equivocal data to support a role for ANP in IOP regulation in human eyes. There are as yet no published data on BNP in human aqueous humour.
METHOD—This was a case-control study. Cases were primary open angle, pseudoexfoliation, and mixed mechanism glaucoma eyes undergoing trabeculectomy. Controls were cataract extraction eyes. There were 47 trabeculectomy eyes (44 patients) and 47 cataract extraction eyes (46 patients) matched for age, sex, race, systemic medications, and type of anaesthetic. 100-200 µl of aqueous humour were aspirated by paracentesis as the first step in the surgical procedure. Peptide levels were later measured by radioimmunoassay.
RESULTS—The presence of BNP and ANP in human aqueous humour was confirmed. BNP was present in higher concentrations than ANP. BNP levels tended to be greater in control eyes—glaucoma median 56.5 (range 0-3526.5) pg/ml versus control median 65.16 (range 0-1788) pg/ml (Wilcoxon signed rank test p = 0.78). ANP levels tended to be greater in glaucoma eyes than in controls: glaucoma median 3 (range 0-68.5) pg/ml versus control median 0 (range 0-60) pg/ml (Wilcoxon signed rank test p = 0.82). ANP and BNP were log linearly related in both groups (r glaucoma group = 0.961, r control group = 0.894).
CONCLUSION—This is the first report of BNP and ANP in human aqueous humour. Peptide levels did not differ significantly between glaucoma and cataract extraction eyes. A linear relation between log BNP and ANP was found. Further studies are required to clarify the role of these peptides in aqueous humour production and IOP regulation.

Keywords: brain natriuretic peptide; aqueous natriuretic peptide; aqueous humour; glaucoma     

Deep sclerectomy with collagen implant: medium term results

AIMS—To study prospectively the success rate and complications of deep sclerectomy with collagen implant (DSCI), a new non-penetrating filtration procedure.
METHODS—Non-randomised prospective trial involving consecutive patients. 100 eyes of 100 patients with medically uncontrolled primary and secondary open angle glaucoma. A superficial scleral flap was raised and a deep sclerectomy was performed in the scleral bed. Schlemm's canal was opened and dissection of the cornea was performed up to Descemet's membrane, at which point aqueous percolated through the remaining trabeculo-Descemet's membrane. A collagen implant was sutured radially in the scleral bed. Visual acuity, intraocular pressure (IOP) measurements, and slit lamp examinations were performed before surgery and after surgery at 1 and 7 days, and 1, 3, 6, 9, 12, 18, 24, 30, and 36 months.
RESULTS—The mean follow up period was 17.8 (SD 8.7) months. The mean preoperative IOP was 27.8 (8.6) mm Hg; the mean postoperative IOP was 5.7 (4.0) at day 1, 11.2 (4.6) at month 1, 14.0 (3.5) at month 12, and 13.0 (3.8) at month 36. Complete success rate, defined as an IOP lower than 21 mm Hg without medication, was 44.6% at 36 months. Qualified success rate, defined as an IOP lower than 21 mm Hg with medication, was 97.7% at 36 months. Early postoperative complications included hyphaema in seven patients, wound leak in 10 patients, and subtle choroidal detachment in 11 patients. Goniopuncture was performed in 41 of the patients, and 5-fluorouracil injections were made in 23 patients; cataract progression occurred in seven patients. When comparing the different types of open angle glaucoma, no difference was found in terms of reduction in IOP, number of patients requiring antiglaucoma medications, or success rate.
CONCLUSIONS—Deep sclerectomy with collagen implant appears to provide reasonable control of IOP at medium term follow up, with few immediate postoperative complications.

Keywords: deep sclerectomy; glaucoma surgery; collagen implant     

A double masked comparison of the intraocular pressure reducing effect of latanoprost 0.005% and 0.001% administered once daily in open angle glaucoma and ocular hypertension

AIM—To compare the intraocular pressure (IOP) reducing effect of latanoprost 0.005% and 0.001%.
METHODS—Twenty four patients with glaucoma or ocular hypertension were randomised into two groups. Twelve patients (group 1) were given latanoprost 0.005% once daily for 4 weeks and then latanoprost 0.001% once daily for the following 4 weeks. Twelve patients (group 2) were given latanoprost 0.001% once daily for 4 weeks and then latanoprost 0.005% for the following 4 weeks.
RESULTS—There was a significant IOP reduction from baseline in both groups on day 28 as well as on day 56. When the results from both groups were used for calculations, the mean IOP reduction from baseline after 4 weeks of treatment with latanoprost 0.005% (day 28 or 56) was 9.6 (SD 3.3) mm Hg (35.0%). After 4 weeks of treatment with latanoprost 0.001%, the IOP reduction (day 28 or 56) was 7.6 (3.4) mm Hg (27.7%). The difference in IOP reduction between the two concentrations was 2.0 (2.3) mm Hg (p<0.001).
CONCLUSIONS—Latanoprost 0.005% was more effective than latanoprost 0.001% in reducing IOP. Even the lower concentration was surprisingly effective, and potentially may be of importance for use in clinical practice. Furthermore, it is at present unknown whether the increase in iris pigmentation seen in certain patients treated with latanoprost 0.005% is dose dependent and might be less pronounced with latanoprost 0.001%. Long term studies with a larger number of patients are required in order to answer this question.

     

Effects on IOP restoration and blood-aqueous barrier after long term treatment with latanoprost in open angle glaucoma and ocular hypertension

AIMS—To evaluate whether long term treatment with the prostaglandin analogue latanoprost has a deleterious effect on the blood-aqueous barrier (BAB) and to determine the duration of the effect on intraocular pressure (IOP) after withdrawal of treatment.
METHODS—Patients with ocular hypertension or glaucoma were topically treated with latanoprost 50 µg/ml once daily for 6-12 months. In 26 patients IOP was followed for 14 days after withdrawal of treatment. Aqueous flare was measured with a laser flare meter during 6-12 months' treatment in 16 patients.
RESULTS—On the last day of treatment IOP was 6.9 mm Hg (95% CI 5.3-8.5) lower than before treatment. It increased slowly during the follow up period but was still 1.3 mm Hg (95% CI 0.2-2.5) lower than pretreatment IOP 14 days after cessation of treatment. No change in aqueous flare was seen throughout the study.
CONCLUSION—Latanoprost has no clinically significant effect on the permeability of the BAB and IOP will return to pretreatment levels within a few weeks, indicating that latanoprost is safe for long term treatment.

     

Tono-Pen determination of intraocular pressure in patients with band keratopathy or glued cornea

AIMS—To evaluate the intraocular pressure (IOP) measurements in patients with band keratopathy or glued corneas obtained from affected and non-affected areas.
METHODS—15 patients with band keratopathy or glued corneas were prospectively recruited. When both eyes were affected, only the right eye was analysed. Tono-Pen readings of IOP were obtained sequentially from the affected and non-affected corneal surface. Additionally, Goldmann applanation tonometry was attempted.
RESULTS—Determination of IOP with the Tono-Pen was possible in all cases, while Goldmann tonometry was not performed in three patients because of severe corneal irregularities. The average of the Tono-Pen readings obtained from the affected cornea (34.8 (SD 14.0) mm Hg) was consistently and significantly higher (p<0.001) than mean IOP obtained by the Tono-Pen from the non-affected area (14.8 (4.3) mm Hg). The average of Goldmann tonometry readings (14.4 (6.1) mm Hg) did not differ significantly from the Tono-Pen values obtained from the non-affected corneal area (p=0.47) but was significantly lower than the Tono-Pen measurements obtained from the affected area (p<0.001)
CONCLUSION—In patients with band keratopathy or glued corneas determination of IOP by Tono-Pen tonometry varies from affected to non-affected area. The Tono-Pen overestimates the level of IOP when it is applied to areas with band keratopathy or with glue.

Keywords: intraocular pressure; applanation tonometry; Tono-Pen; keratopathy     

CA 19-9 ELISA test: a new method for studying mucus changes in tears

AIMS—This study investigated mucus changes in the tears in various eye conditions using impression cytology. The quantity of mucins was measured by enzyme linked immunosorbent assay (ELISA) using the tumour marker CA 19-9. This assay quantifies the sialylated Lewis^a structure mainly associated with ocular mucins.
METHODS—Impression cytology was performed using a cellulose nitrate membrane, on 53 healthy patients, 50 glaucoma patients treated with β blockers, 24 patients suffering from dry eye syndrome, and 45 contact lens wearers. The tear film glycoproteins were eluted and CA 19-9 was measured.
RESULTS—CA 19-9 content expressed as kilo units (kU) per µg of tears was significantly decreased in dry eye syndrome (25.8 kU (SD 17.3)/µg) (p<0.05), glaucoma patients over 60 years (28.9 (19.5) kU/µg) (p<0.05), and contact lens wearers (28.4 kU (18)/µg) (p<0.05), when compared with healthy individuals (39.4 kU (22.2)/µg).
CONCLUSION—Impression cytology can be regarded as a valuable method for obtaining samples of glycoconjugates of mucin. The decrease of sialylated chains observed with this method confirms the hypothesis that some quantitative changes in the tear film may be encountered in ocular surface disorders.

Keywords: impression cytology; tears; glycoconjugate; sialic acid     

Histomorphometry of the optic disc in highly myopic eyes with absolute secondary angle closure glaucoma

AIM—To evaluate histomorphometrically the optic nerve head in highly myopic eyes with absolute secondary angle closure glaucoma.
METHODS—Optic disc sections of 16 highly myopic eyes with an axial length of more than 26 mm and of 19 eyes with an axial length of less than 26 mm were histomorphometrically evaluated. All eyes had been enucleated due to painful absolute secondary angle closure glaucoma.
RESULTS—In the highly myopic eyes compared with the non-highly myopic eyes, mean optic disc diameter was significantly larger (mean 2.33 (SD 0.55) mm versus 1.77 (0.50) mm; p=0.01), and the optic cup was significantly shallower (optic cup depth 0.34 (0.29) mm versus 0.63 (0.23) mm; p=0.03). The peripapillary scleral ring was significantly broader (0.58 (0.65) mm versus 0.08 (0.06) mm; p=0.001), and the β zone (0.83 (0.74) mm versus 0.28 (0.25) mm; p=0.006) of the parapapillary chorioretinal atrophy was significantly larger in the highly myopic eyes.
CONCLUSIONS—The results of the present study agree with biomorphometric data of the optic nerve head in highly myopic eyes with glaucoma. In the highly myopic group, a markedly enlarged peripapillary scleral ring characterised by absence of Bruch's membrane and choriocapillaris contributes in addition to α and β zone to the parapapillary atrophy.

Keywords: optic disc; histomorphometry; myopia; angle closure glaucoma     

Short term comparative study of topical 2% carteolol with and without benzalkonium chloride in healthy volunteers

AIM—A crossover, randomised double blind study was undertaken in 30 healthy volunteers, in order to compare the tolerance of 2% carteolol with and without preservative in short term use.
METHODS—Complete ophthalmic examinations were performed before and 30, 60, and 180 minutes after instillation of one drop of the solution, and after 3 days of preservative treatment. After a 5 day washout, the same examinations were done with the second drug.
RESULTS—Results showed good general tolerance for both formulations. No significant difference in subjective tolerance, corneal aesthesiometry, punctuate keratitis, Schirmer's test, intraocular pressure (IOP) decrease (about 25% in the two groups at 3 hours, 10% after 3 days of treatment), resting cardiac frequency, or blood pressure was observed. However, break up time was significantly reduced from baseline by preserved carteolol both at 3 hours (10.40 (5.9) seconds to 6.15 (3.9) seconds, p=0.001) and after 3 days (7.72 (5.5) seconds, p=0.04). Preservative free carteolol did not significantly change the break up time (baseline 9.08 (5.7) seconds; 3 hours = 7.88 (5.5) seconds, not significant; day 3 = 8.35 (5.8), non-significant).
CONCLUSIONS—These results confirm that carteolol is well tolerated, either with or without preservative. The preservative free group showed better stability of the tear film, without loss of effect on IOP. This difference, although mild in the healthy young subjects in the present study could be much more relevant in those patients treated long term, older patients, and/or those suffering from ocular surface disorders. In such instances, preservative free drugs could be of potential benefit to protect the lacrimal fluid integrity and corneoconjunctival surface.

Keywords: glaucoma; carteolol; benzalkonium; preservatives; β blockers     

Trabeculectomy with intraoperative sponge 5-fluorouracil in Afro-Caribbeans

AIM—To study the efficacy and safety of intraoperative 5-fluorouracil (5-FU) in Afro-Caribbean patients.
METHODS—The results of trabeculectomy in 18 eyes of 18 Afro-Caribbean patients in whom a sponge soaked in 25 mg/ml solution of 5-FU was applied between Tenon's capsule and sclera for 5 minutes before excision of the trabecula were compared with 16 eyes of 16 Afro-Caribbean patients matched for age, quantity, and duration of preoperative medications, who underwent trabeculectomy without 5-FU.
RESULTS—The mean postoperative intraocular pressure (IOP) at 1 month was 15.6 (SD 6.1) mm Hg in the 5-FU group and 18.0 (5.2) mm Hg in the control group (p=0.15). There was no significant difference in the IOP at 6, 12, 15, 18, and 24 months in the two groups. Success rate at 18 months defined as an IOP less than or equal to 21 mm Hg with no adjunctive medication was 56% in the 5-FU group and 55% in the control group. No major complications were noted in either group.
CONCLUSION—Intraoperative sponge 5-FU alone is safe but does not appear to decrease the risk of failure of trabeculectomy in Afro-Caribbeans.

     

Pars plana vitrectomy with pars plana tube implantation in eyes with intractable glaucoma

AIMS—Intractable glaucoma is glaucoma resistant to medical therapy and conventional surgical procedures. In this study, a planned surgical technique is discussed for controlling the increased intraocular pressure in selected cases with intractable glaucoma.
METHODS—Total pars plana vitrectomy with pars plana tube implantation was performed in 17 eyes of 17 cases with intractable glaucoma. Patients with neovascular glaucoma were not included in this study. The mean age of these patients (seven men, 10 women) was 44.6 (SD 22.1) years and mean follow up period was 30.3 (15.5) months (range 4-71). Drainage implants with a disc were used in 16 cases, whereas, a tube with scleral buckle (Schocket surgery) was preferred in one case. An intraocular pressure below or equal to 20 mm Hg without any adjunctive medication or with only one type of antiglaucomatous drop was considered as an adequate operative outcome.
RESULTS—16 out of 17 eyes maintained adequate pressure control. Only three out of these 16 eyes required prophylactic antiglaucomatous medications. One patient underwent reoperation for pressure control. The most severe complications observed postoperatively were intravitreal haemorrhage (one case), choroidal detachment (one case), implant failure (one case), total retinal detachment (two cases), and corneal endothelial decompensation (five cases).
CONCLUSION—Pars plana placement of drainage tube following pars plana vitrectomy should be considered as an alternative method for controlling increased intraocular pressures in selected patients with intractable glaucoma.

Keywords: glaucoma; pars plana vitrectomy; pars plana tube implantation     

Sensitivity and specificity of optic disc variables and analysis of a new variable (MP/D) for glaucoma diagnosis with the Glaucoma-Scope

AIM—In an attempt to use the quantitative optic disc measurements of the Glaucoma-Scope (OIS Sacramento, CA, USA) to distinguish glaucomatous from normal optic discs, a new variable was investigated, the mean disc corrected for the disc size by dividing by the disc area: MP/D.
METHODS—Glaucoma-Scope disc evaluation was performed on 81 eyes of 51 patients split into the following groups based on Humphrey 24-2 visual field and clinical criteria of glaucoma: chronic glaucoma n=27 (including only early, n=17, and low tension glaucoma, n=10), ocular hypertension n=24, pseudoglaucomatous large discs, n=12, and normal eyes, n=18. Classic optic disc variables (the vertical and horizontal c/d ratios, and the c/d area) were compared with the new MP/D index calculating receiver operating characteristic curves.
RESULTS—The MP/D ratio was able to identify the glaucomatous eyes more easily than other ratios. Areas under the curves were: 0.91 (MP/D); 0.87 (c/d area); 0.85 (c/d vertical); and 0.80 (c/d horizontal). The MP/D index was also correlated with the mean deviation (r=0.466; p=0.001).
CONCLUSION—MP/D may prove useful in detecting glaucomatous optic nerve damage and could be an interesting screening tool for primary open angle glaucoma.

     

Vertical cup/disc ratio in relation to optic disc size: its value in the assessment of the glaucoma suspect

AIMS—The vertical cup/disc ratio (CDR) has long been used in the assessment of the glaucoma suspect, though the wide range of CDR values in the normal population limits its use. Cup size is related physiologically to disc size and pathologically to glaucomatous damage. Disc size can be measured at the slit lamp as the vertical disc diameter (DD). The ability of the CDR, in relation to DD, to identify glaucomatous optic discs was investigated.
METHODS—88 normal, 53 early glaucoma, and 59 ocular hypertensive subjects underwent stereoscopic optic disc photography and clinical biometry. Photographs were analysed in a masked fashion by computer assisted planimetry. The relation between vertical cup diameter and DD was explored by linear regression, and expressed in terms of CDR. The upper limit of normal was defined by the 95% prediction intervals of this regression (method 1) and by the upper 97.5 percentile for CDR (method 2). The sensitivity and specificity of CDR to identify an optic disc as glaucomatous was tested with these disc size dependent and disc size independent cut offs in small, medium, and large discs.
RESULTS—The CDR was related to DD by the equation CDR = (−1.31 + (1.194 × DD))/DD. The sensitivity in small, medium, and large discs was 80%, 60%, and 38% respectively for method 1 and 33%, 67%, and 63% respectively for method 2. Specificity was 98.9% (method 1) and 97.7% (method 2).
CONCLUSIONS—The CDR, relative to disc size, is useful clinically, especially to assist in identifying small glaucomatous discs.

Keywords: cup/disc ratio; glaucoma; imaging     

Intraocular pressure and central visual field of normal tension glaucoma

AIM—To study whether damage in the central 30° field of normal tension glaucoma (NTG) is relatively heterogeneous or homogeneous with respect to intraocular pressure (IOP) related damage.
METHODS—Using the results of Humphrey perimeter examinations, the central 30° field was divided into four subfields; superior and inferior hemifields excluding the caecocentral field (30-2 program) and superior and inferior 10° hemifields (10-2 program). In 103 NTG cases, the intraindividual bilateral difference in the mean of total deviations (mean TD) in the four subfields was analysed by multiple linear regression to correct the effects of factors other than IOP. Explanatory variables were the intraindividual bilateral difference in the mean of clinic IOP (IOP_mean), that in the ratio of area of peripapillary atrophy corresponding to each subfield to disc area, and that in myopic refraction.
RESULTS—The intraindividual bilateral difference in the mean TD was significantly and negatively correlated with that in IOP_mean in three of the above four subfields (p<0.005) and correlation tended to be negative (p=0.07) in the superior 10° hemifield.
CONCLUSIONS—Diffuse IOP related damage was suggested in the central 30° field of NTG; greater extent of the damage in the above four subfields was correlated with higher mean IOP. The present findings may have clinical implications.

     

Impaired motion sensitivity as a predictor of subsequent field loss in glaucoma suspects: the Roscommon Glaucoma Study

AIM—To determine if impaired motion sensitivity is a significant predictor of subsequent field loss in glaucoma suspects.
METHOD—A population based prospective study; a 5 year follow up of all glaucoma suspects who had been identified from a population based random sample survey in the west of Ireland. 78 glaucoma suspects whose visual field function was annually measured by Henson CFS 2000 and for whom data on family history of glaucoma, ocular status, and motion impairment had been recorded. Visual field loss was defined as Henson visual field survival score of 94 or less.
RESULTS—18 people developed visual field loss in at least one eye. Motion impairment at baseline was associated with a 2-18 times greater risk of development of the visual field loss (p<0.001). This association was independent of sex, family history of glaucoma, intraocular pressure, and C/D ratio at baseline. The Cox's proportional hazards regression analysis confirmed the above results after adjustment for age and the C/D ratio.
CONCLUSION—Motion impairment is an independent predictor of visual field loss in glaucoma suspects, although it is not clear how long motion impairment precedes visual field loss.

Keywords: glaucoma; perimetry; screening; motion     

Neuroretinal rim width ratios in morphological glaucoma diagnosis

AIMS—To evaluate the inferior to temporal neuroretinal rim width ratio and superior to temporal rim width ratio as measures of rim shape for diagnosis of glaucoma.
METHODS—Colour stereo optic disc photographs of 527 normal subjects, 100 ocular hypertensive individuals with normal visual fields, and 202 open angle glaucoma patients with a mean perimetric defect of less than 10 dB were morphometrically evaluated. Eyes with an optic cup area of < 0.2 mm² were excluded.
RESULTS—In the normal subjects, inferior to temporal rim width ratio (1.67 (SD 0.53)) was significantly (p<0.0001) higher than superior to temporal rim width ratio (1.56 (0.49)). Both ratios were significantly (p<0.0001) higher the more vertically the optic disc was configured. In the normal eyes, both ratios were statistically independent of disc size, rim area, refractive error, age, and sex. With the differences being more marked for the inferior to temporal ratio than for the superior to temporal ratio, both rim width ratios were significantly (p<0.005) lower in the ocular hypertensive group than in the normal group. Despite the high significance of the differences, diagnostic power of the inferior ratio and the superior ratio was 59% and 58%, respectively, indicating a marked overlap between the groups.
CONCLUSIONS—Abnormally low inferior to temporal and superior to temporal rim width ratios can indicate glaucomatous optic nerve damage in some ocular hypertensive eyes. Being independent of optic disc size and ocular magnification, the rim width ratios may be taken as one among other variables for the ophthalmoscopic optic disc evaluation, taking into account, however, a pronounced overlap between normal eyes and ocular hypertensive eyes.

Keywords: neuroretinal rim width ratios; glaucoma; ocular hypertension     

Blue-yellow colour vision in an onchocercal area of northern Nigeria

AIM—To determine if the City University Tritan Test is a useful addition to visual function assessment in rural communities in northern Nigeria.
METHODS—The study was a cross sectional survey. The participants were 8394 people, aged 5 years and over, living in 37 rural communities, mesoendemic and non-endemic for onchocerciasis, in Kaduna State in northern Nigeria. The main outcome measures were the detection of a defect in blue-yellow colour vision by two criteria: (1) failure with the City University tritan screening plates; (2) failure with the City University grading plates to identify severe tritan defects.
RESULTS—91% of those aged 10 years and above could perform the test. Below this age, there were difficulties in comprehension. The test showed good inter- and intraobserver agreement. After adjustment for confounders the odds of failing the screening plates were significantly increased in the presence of optic atrophy or glaucoma (3.55 (2.48-5.08) and 15.9 (4.22-60.2) respectively). There was a greater increase in the adjusted odds of failing the grading plates in the presence of optic atrophy or glaucoma (5.30 (2.97-9.45) and 8.87 (1.61-48.7) respectively). Cataract had a smaller effect on the screening plates, adjusted odds 1.63 (0.95-2.80).
CONCLUSION—Blue-yellow colour vision testing is a useful addition to visual function assessment in those aged 10 years and above in rural northern Nigeria, particularly in the detection of optic nerve disease.

Keywords: tritan defects; optic nerve disease; onchocerciasis; visual function assessment