[Visual field loss in eyes undergoing minimally invasive glaucoma surgery in Iceland].

INTRODUCTION: Glaucoma is a degenerative disease of the optic nerve and is marked by visual field defects (VFD). The only approved treatment is IOP lowering, either with eye drops, laser or surgery. Minimally invasive glaucoma surgery (MIGS) has become an appealing treatment modality, offering IOP lowering effect without the complication rates of trabeculectomy or the patient adherence required for pharmacologic therapy. In this study we aim to describe the severity of VFD in patients undergoing their first MIGS surgery. METHODS: Retrospective study reviewing the medical records of all patients that underwent MIGS surgery at the University Hospital of Iceland from January 2019 to June 2020. Eyes with previous glaucoma surgeries and secondary glaucomas were excluded. The results were divided into two groups, MIGS with phacoemulsification and standalone MIGS. RESULTS: 112 eyes included in the study. Mean age 74.5 ± 10.6 years. The mean defect (MD) score was 8.8 ± 6.4 and the number of glaucoma medications 1.8 ± 1.0 for the group as a whole. Significant difference (p<0.01) was between the age, MD score and the number of glaucoma medications between the two groups. Looking at the eyes that did not undergo phacoemulsification a significant difference (p<0.05) was between the MD score of primary open angle glaucoma eyes, 11.2 ± 6.5 dB and pseudoexfoliation glaucoma, 6.0 ± 3.3 dB. CONCLUSION: Visual field defect and the number of glaucoma medications at referral to surgery was markedly less compared to a trabeculectomy study done in Iceland 3 years prior. Few comparable studies include MD score in their results, most focus on changes in intraocular pressure. Comparing the MD score to three studies from Germany and Austria the MD score seems to be similar. In our study a lower MD score for pseudoexfoliation glaucoma implies that Icelandic ophthalmologists send pseudoexfoliation eyes earlier for an operation.

[Glaucomatous visual field loss in eyes undergoing first trabeculectomy in Iceland]. / Sjónsviðsskerðing við fyrstu hjáveituaðgerð (trabeculectomiu) vegna gláku

INTRODUCTION: Glaucoma is a degenerative disease in the optic nerve with associated visual field defects (VFD). Trabeculectomy is the most common glaucoma surgery. Surgery is indicated if glaucomatous optic neuropathy progresses despite tolerated medical treatment or in patients with severe VFD. The purpose of this paper is to describe the severity of visual field damage in patients undergoing their first trabeculectomy in Iceland. METHODS: A retrospective review of medical records of all patients with open angle glaucoma that underwent first trabeculectomy at Landspítali University Hospital, from June 2013 to March 2016. Visual fields were examined by Octopus automated perimetry and the severity of glaucoma damage was staged according to the mean defect (MD). RESULTS: 86 eyes were included in the study, mean age 75 ± 11 years, 57% men. Patients used on average three IOP lowering medications. Mean MD at referral to surgery was 13.4 ± 7.7dB (min 0.8dB, max 26.2 dB), 21% had early glaucomatous damage (MD <6dB), 23% moderate (MD 6-12 dB) and 56% severe (MD > 12). CONCLUSION: VFD at referral to surgery varied from mild VFD to severe damage. Like clinical guidelines recommend, treatment seems to be individualized and the most common indication for surgery was increased VFD despite medical treatment. Mean MD at referral to surgery was high compared to other studies. Eyes with severe VFD had on average lower IOP and thinner cornea. This might indicate that great emphasis is placed on high IOP and perhaps too little emphasis on VFD and cornea thickness.

[Medical management of glaucoma and interaction between glaucoma and systemic medications].

INTRODUCTION: Glaucoma used to be the most common cause for blindness in Iceland. As the incidence of glaucoma increases with age, the patients often have numerous comorbidities and use various medications. It is important to keep in mind interactions and side effects of glaucoma medications when deciding systemic medical treatment for these patients to ensure their safety and comfort. The goal of the study was to gather information about drug use of patients with severe glaucoma. METHODS: A retrospective study where data were collected from 100 consecutive patients who underwent a trabeculectomy as first glaucoma surgery at Landspitali National University Hospital of Iceland during 2013-2017. All systemic and ophthalmic medications during 6 months before and after the surgery, medical diagnoses, age and gender of the patients were registered. RESULTS: Of all 100 patients, 87 used systemic medication, averaging 5.3 drugs/patient. Mean number of glaucoma medication used was 3.0. Mean age at surgery was 75 years and 53 were women. The most common systemic drug class was anti-hypertensives, used by 57 patients where beta-blockers were the most common, used by 30 patients. Zopiclone was the most common single drug, used by 29 patients. CONCLUSION: It is evident that patients with glaucoma take various drugs for systemic illness that can affect their glaucoma and have interactions with glaucoma drugs. It is urgent that healthcare providers keep this in mind when deciding on systemic treatment for patients with glaucoma, with regards to possible interactions with glaucoma drugs and the effect on patient's overall health.

Can postoperative dexamethasone nanoparticle eye drops replace mitomycin C in trabeculectomy?

PURPOSE: Compare (a) nonmitomycin C (MMC) trabeculectomy and 1.5% dexamethasone nanoparticle (DexNP) eye drops postoperatively with (b) trabeculectomy with MMC and Maxidex® eye drops postoperatively. METHODS: Randomized prospective single masked clinical trial with 20 patients with primary open-angle glaucoma undergoing primary trabeculectomy. The study group consisted of 10 patients without MMC intraoperatively and postoperative DexNP eye drops, and the control group consisted of 10 patients treated with MMC intraoperatively and postoperative Maxidex® . The drops were tapered out over 8 weeks. The main outcome measures were as follows: rates of complete success, that is intraocular pressure (IOP) within target pressures at different time-points without IOP-lowering medication, or reoperation. Secondary outcome measures included the following: relative success rate (with IOP-lowering medications), number of glaucoma medications and reoperations. Patients were followed for 36 months. RESULTS: Both groups showed similar postoperative course and IOP reduction. Intraocular pressures (IOPs) in the DexNP group and in the control group were 25.6 and 24.4 mmHg, respectively, at baseline. Intraocular pressures (IOPs) were reduced to 13.2 and 14.5 mmHg at 12 months, 11.7 and 12.6 mmHg at 24 months and 11.7 and 12.1 mmHg at 36 months, respectively. There were no statistically significant differences between the groups in absolute (p = 0.36) or relative (p = 1.0) success rates, number of medications (p = 0.71) or reoperations (p = 1.0) between the groups at any time-point. CONCLUSIONS: DexNP eye drops are effective postoperative treatment following trabeculectomy. The potent anti-inflammatory and antifibrotic effect of DexNP may offer an alternative to mitomycin C in glaucoma surgery.

[Case report: Two patients with eye worm and recurrent swelling of the extremities].

We report two cases of Loa loa (eye worm) infection in Iceland; the former in a 35-year-old woman born in Africa but living in Iceland for several years; the latter in a 31-year- old woman who had traveled in Africa. Both women sought medical attention due to discomfort in one eye. On exami-nation a worm was noted in both cases, moving under the conjunctiva, 3 cm in length and 0.5 mm in diameter. Both patients also had symptoms from the extremities; episodic swelling and itching in the former case, and muscle pain in the latter. Both patients were diagnosed with loiasis with Calabar swellings of the extremities and were successfully treated with albendazole and diethylcarbamazine. Increased awareness is needed for infections which previously have been rare in the Nordics.

Retinal oxygen metabolism in healthy subjects and glaucoma patients.

BACKGROUND: To test whether retinal oxygen metabolism is different in glaucoma patients compared with healthy subjects. METHODS: This was a two-centre study where retinal vessel oxygen saturation was measured in glaucoma patients and healthy individuals with a non-invasive spectrophotometric retinal oximeter. Visual fields were obtained in the glaucoma patients. RESULTS: No statistical difference was found in retinal oxygen saturation in arterioles (p=0.16), venules (p=0.16) and arteriovenous difference (p=0.24) when all glaucoma patients (n=74) were compared with healthy individuals (n=89). When patients with advanced glaucoma (visual field mean defect (MD ≥ 10 dB, n=21)) were compared with healthy individuals, the oxygen saturation in venules was higher in glaucoma patients (58.2% ± 5.4% vs 53.8% ± 6.4%; p=0.0054, mean ± SD) and the arteriovenous difference was lower in glaucoma patients (36.4% ± 4.7% vs 39.5% ± 5.7%; p=0.021). In glaucoma patients with mild glaucoma (visual field MD ≤ 5 dB, n=33), no statistical differences were found in retinal oxygen saturation compared with healthy individuals. CONCLUSIONS: Glaucoma patients with advanced glaucoma have higher oxygen saturation in venules and lower arteriovenous difference in oxygen saturation compared with healthy individuals. The decreased arteriovenous difference in severe glaucoma may be related to lower oxygen consumption secondary to neuropathy.

Retinal oximetry in primary open-angle glaucoma.

PURPOSE. To determine whether retinal vessel oxygen saturation is affected in primary open-angle glaucoma (POAG) patients. METHODS. Retinal oxygen saturation in patients with POAG was measured in retinal vessels with a spectrophotometric retinal oximeter in darkness, and visual fields were obtained. Oxygen tension (Po(2)) was calculated from oxygen saturation values. Statistical analysis was performed using Pearson's correlation and Student's t-test. RESULTS. Mean oxygen saturation in venules was higher in persons with poor visual fields (68% ± 4%, mean ± SD) than in those with good visual fields (62% ± 3%; P = 0.0018). The mean arteriovenous difference in oxygen saturation was lower in persons with poor visual fields (30% ± 4%, n = 9) than in those with good visual fields (37% ± 4%; P = 0.0003; n = 12). No correlation was found between saturation in retinal arterioles and visual field mean defect (n = 31; r = -0.16; P = 0.38). Oxygen saturation in retinal venules correlated positively with worsening visual field mean defect (r = 0.43; P = 0.015). Arteriovenous difference in oxygen saturation decreased significantly as the visual field mean defect worsened (r = -0.55; P = 0.0013). Mean Po(2) in venules was 38 ± 3 mm Hg. It was significantly higher in persons with poor visual field fields (40 ± 3 mm Hg) than in those with good visual fields (36 ± 2 mm Hg; P = 0.0016). CONCLUSIONS. Deeper glaucomatous visual field defects are associated with increased oxygen saturation in venules and decreased arteriovenous difference in retinal oxygen saturation. The data suggest that oxygen metabolism is affected in the glaucomatous retina, possibly related to tissue atrophy.

Common variants near CAV1 and CAV2 are associated with primary open-angle glaucoma.

We conducted a genome-wide association study for primary open-angle glaucoma (POAG) in 1,263 affected individuals (cases) and 34,877 controls from Iceland. We identified a common sequence variant at 7q31 (rs4236601[A], odds ratio (OR) = 1.36, P = 5.0 × 10⁻¹°). We then replicated the association in sample sets of 2,175 POAG cases and 2,064 controls from Sweden, the UK and Australia (combined OR = 1.18, P = 0.0015) and in 299 POAG cases and 580 unaffected controls from Hong Kong and Shantou, China (combined OR = 5.42, P = 0.0021). The risk variant identified here is located close to CAV1 and CAV2, both of which are expressed in the trabecular meshwork and retinal ganglion cells that are involved in the pathogenesis of POAG.

Glaucoma filtration surgery and retinal oxygen saturation.

PURPOSE: Glaucoma may involve disturbances in retinal oxygenation and blood flow. The purpose of this study was to measure the effect of glaucoma filtration surgery on retinal vessel oxygen saturation. METHODS: A noninvasive spectrophotometric retinal oximeter was used to measure hemoglobin oxygen saturation in retinal arterioles and venules before and after glaucoma filtration surgery. Twenty-five consecutive patients were recruited, and 19 had adequate image quality. Fourteen underwent trabeculectomy and five glaucoma tube surgery. Twelve had primary open-angle glaucoma and seven had exfoliative glaucoma. IOP decreased from 23 +/- 7 to 10 +/- 4 mm Hg (mean +/- SD, P = 0.0001). RESULTS: Oxygen saturation increased in retinal arterioles from 97% +/- 4% to 99% +/- 6% (n = 19; P = 0.046) after surgery and was unchanged in venules (63% +/- 5% before surgery and 64% +/- 6% after, P = 0.76). There were no significant changes in saturation in the fellow eyes (P > 0.60). The arteriovenous difference was 34% before and 36% after surgery (P = 0.35). CONCLUSIONS: Glaucoma filtration surgery had almost no effect on retinal vessel oxygen saturation.