IBN AL-NAFIS

 

ʿAlāʾ al-Dīn Abū al-Ḥasan ʿAlī ibn Abī Ḥazm al-Qarashī, better known as Ibn al-Nafīs, is regarded as: 

• the "father of circulatory physiology"
• the “greatest physician of his time”
• the “greatest physiologist of the Middle Ages”
• the “author of the largest encyclopedia by a single person”
• mentioned by some historians as the “second Ibn Sina”

He was the first person to challenge the long-held contention of the Galen School that blood could pass through the cardiac interventricular septum, and in keeping with this he believed that all the blood that reached the left ventricle passed through the lung. He also stated that there must be small communications or pores (manafidh in Arabic) between the pulmonary artery and vein, a prediction that preceded by 400 years the discovery of the pulmonary capillaries by Marcello Malpighi. 

He was one of the many Arab polymaths, that is scholars who worked in a large number of different areas. It is presumed that Al-Nafis wrote more than 110 volumes of medical textbooks.

Ibn al-Nafis was born around 1210-1213 in Karashia, a village near Damascus. He studied theology, philosophy, and literature. At the age of 16, he went to Nuri Hospital in Damascus and studied medicine there for 10 years. At the age of 23, he was invited to Egypt by the Ayyubid Sultan Al-Kamil. There, he was appointed as the chief physician at al-Naseri Hospital. He also taught jurisprudence at Al-Masruriyya Madarsa. He passed away in Cairo on 17th December 1288.

Among the various treatises written by Ibn al-Nafis, the most voluminous is the Al-Shamil fi Al-Tibb (The Comprehensive Book on Medicine). It was planned as a 300-volume encyclopedia, however, only 80 volumes could be completed by Ibn al-Nafis. It is one of the largest medical encyclopedias ever written by one person, and it gave a complete summary of the medical knowledge in the Islamic world at the time. His most famous treatise is regarded as the Sharh Tashrih al-Qanun ("Commentary on Anatomy in Books I and II of Ibn Sina's Kitab al-Qanun"), which he wrote at the age of 29 years.

The opening page of a book on medicine by Ibn al-Nafis

He also wrote a book on ophthalmology titled “al-Muhaḏḏab fī al-Kuhl” (“Polished Book on ophthalmology”); an original book on ophthalmology. Ibn al-Nafis wrote this book to polish and build on the concepts of ophthalmology originally made by Masawaiyh and Ibn Ishaq.

REFERENCES:

• West JB. Ibn al-Nafis, the pulmonary circulation, and the Islamic Golden Age. J Appl Physiol (1985). 2008 Dec;105(6):1877-80. doi: 10.1152/japplphysiol.91171.2008. Epub 2008 Oct 9. PMID: 18845773; PMCID: PMC2612469.

• Light From the East: How the Science of Medieval Islam Helped to Shape the Western World, John Freely.
• Galileo Goes to Jail and Other Myths about Science and Religion, Edited by Ronald L. Numbers.
• Feucht, Cynthia; Greydanus, Donald E.; Merrick, Joav; Patel, Dilip R.; Omar, Hatim A. (2012). Pharmacotherapeutics in Medical Disorders. Walter de Gruyter. p. 2. ISBN 978-3-11-027636-7.
• Moore, Lisa Jean; Casper, Monica J. (2014). The Body: Social and Cultural Dissections. Routledge. p. 124. ISBN 978-1-136-77172-9.

BIO-INTERVENTIONAL CYCLODIALYSIS AND SCLERAL REINFORCEMENT

 

Iantrek, a company based in the USA, has developed a bio-interventional cyclodialysis and scleral reinforcement procedure. It is being used in open-angle glaucoma (OAG) patients undergoing cataract surgery. 

CYCLO-PEN

SCAFFOLD IMPLANTATION

An ab-interno approach is used to create a sectoral cyclodialysis in OAG patients. Subsequently, visco-cycloplasty with scleral reinforcement using a homologous minimally modified allograft scaffold is performed to maintain the patency of the cyclodialysis reservoir and increase uveoscleral outflow.

From a mechanistic standpoint, cyclodialysis has a dual mechanism of IOP lowering, through increased uveoscleral outflow as well as reduction in aqueous production from the detached ciliary body.

Bio-reinforced cyclodialysis technique uses adjunct allogeneic scleral tissue scaffolding as reinforcement to prevent the premature closure of the cyclodialysis intervention by maintaining a permanent uveoscleral conduit for aqueous outflow. An internal uveoscleral filtration reservoir is thus supported by the allogeneic bio-scaffold, which acts as a biologic non-absorbable spacer between the ciliary body and the adjacent scleral wall.

The CREST clinical study is a real-world evidence registry in which patients are followed prospectively through 24 months after undergoing cyclodialysis intervention. The results of a multi-center study involving 12 surgeons from the CREST US and OUS clinical studies have been published recently.

As per the results of the study, successful cyclodialysis and allograft bio-scaffold reinforcement was achieved in 117 eyes.

At baseline, mean BCVA was 0.48 (95% CI: 0.42‒0.54; 20/40 Snellen), and mean ± SD medicated IOP was 20.2 ± 6.0 mmHg on 1.4 ± 1.3 IOP-lowering medications.

At 12 months, there was a 27.1% reduction from baseline mean medicated IOP. In eyes with medicated baseline IOP > 21 mmHg (n = 45), there was a 39.7% paired IOP reduction at 12 months with a concurrent reduction in the mean number of IOP lowering medications to 0.8 ± 0.9 which was statistically significant (p < 0.01).

81.9% of eyes achieved a medicated IOP ≤ 18 mmHg with no increase in medications at 12 months.

Complications included minimal blood reflux from the cyclodialysis cleft, which was not associated with any significant postoperative hyphema, transient hypotony occurred in one eye, three patients who underwent concurrent phaco surgery developed cystoid macular edema,

Secondary glaucoma surgery such as Selective Laser Trabeculoplasty (SLT), Ahmed Valve or Xen-gel implantation, and cyclophotocoagulation was performed in 3.2% of the cases.

REFERENCE:

Ianchulev T, Weinreb RN, Calvo EA, Lewis J, Kamthan G, Sheybani A, Rhee DJ, Ahmed IK. Bio-Interventional Cyclodialysis and Allograft Scleral Reinforcement for Uveoscleral Outflow Enhancement in Open-Angle Glaucoma Patients: One-Year Clinical Outcomes. Clin Ophthalmol. 2024;18:3605-3614. https://doi.org/10.2147/OPTH.S496631.

FOR COMPANY DETAILS PLEASE CLICK THE LINK BELOW:

https://iantrekmed.com/

 

ROLE OF ETHNICITY IN GLAUCOMA

 

Glaucoma is globally more prevalent among the Black population, compared with white patients, develops 10 years earlier on average, and is 15 times more likely to cause visual impairment. The outcomes of medical and surgical treatment for glaucoma are worse for black than white populations.

An observational study was performed in the UK to assess whether patients from minority ethnic groups have different perceptions about the quality-of-life (QOL) outcomes that matter most to them.

The study involved 511 patients diagnosed with primary open-angle glaucoma and ocular hypertension.

The self-reported priorities for health outcomes among the responders was divided into:

(1) vision, (2) drop freedom, (3) intraocular pressure (IOP), and (4) one-time treatment.

For White patients, the priority for QOL was good vision.

However, for Black/Black British patients the priority was drop freedom, followed by control of IOP and finally the possibility of one-time treatment.  

For Asian/Asian British patients, the priority was control of IOP. This was almost the same as the priority for vision.

Other ethnic minority groups also had higher odds ratios (ORs) for prioritizing health outcomes other than vision alone: 4.50 (1.03 to 19.63, p=0.045) for drop freedom and 5.37 (1.47 to 19.60, p=0.011) for IOP.

The study showed that ethnicity is strongly associated with differing perceptions regarding health outcomes and QOL priority. Therefore, an individualized and ethnically inclusive approach is needed when selecting and evaluating treatments in clinical and research settings.

Certain important implications from this study include the fact that the patient’s priority for care may not be the same as the treating physician. A large number of patients in this study regarded freedom from drops as the most important priority. This implies that minimally-invasive glaucoma surgeries (MIGS) and laser procedures such as selective laser trabeculoplasty (SLT) could be a useful approach in making the patient drop-free. Therefore, non-white patients could be more perceptive for such procedures.

It also shows that black patients may not use their eye drops regularly, causing detrimental outcomes.

Furthermore, QoL outcomes from studies which predominantly recruit certain ethnic groups may not be generalizable to other ethnic groups. This requires a tailored-approach to perform QOL studies.

In conclusion, ethnicity plays a major role in the occurrence of glaucoma, the management profile, and the perceptions of patients across various ethnicities.

REFERENCE:

Safitri A, Konstantakopoulou E, Gazzard G, et al. Priorities for health outcomes in glaucoma in an ethnically diverse UK cohort: an observational study. BMJ Open 2024;14:e081998. doi:10.1136/ bmjopen-2023-081998

A 1938 ARTICLE ON PATHOGENESIS OF GLAUCOMA

 

A wonderfully elaborate article was published in 1938 by Elwyn regarding the pathogenesis of chronic simple glaucoma (primary open-angle glaucoma).

According to him, intraocular pressure (IOP) depends on the tension exerted on the sclera by the intraocular structures. These structures include the sclera, the iridocorneal angle, the ciliary body, the vitreous, and the choroid.

The theories regarding the causation of glaucoma can be classified as follows:

1. Retention theories, based on a hindrance to the elimination of the aqueous
2. Theory based on an increase in the production of aqueous
3. Theory based on an increase in the volume of one or more of the intraocular structures

RETENTION THEORIES:

Retention due to a change in the sclera:

According to this theory, the sclera loses its elasticity and shrinks, and that affects the normal outflow of the aqueous out of the eye. The loss of elasticity is either due to a senile change or to the sequence of inflammatory changes.

Retention of aqueous in the eye due to block at the iridocorneal angle:

1. This can happen due to pressure of the iris against the angle. It can occur from inflammatory changes in the anterior segment of the eye followed by adhesions between the iris and the cornea;
2. It can also occur from deposits of pigment in the pectinate ligament
3. Or due to primary sclerosis of the pectinate ligament

Retention can also occur due to blocking of the aqueous outflow in the iris as a result of a deposit of pigment or from degenerative changes.

THEORY BASED ON AN INCREASE IN THE PRODUCTION OF AQUEOUS:

An increase in the production of aqueous has been assumed to be due to disturbances in innervation and to inflammatory and degenerative causes.

THEORY BASED ON AN INCREASE IN THE VOLUME OF THE INTRA-OCULAR STRUCTURES:

Vitreous:

The vitreous, behaves as a colloid, and swells when it is turned acidic. It is presumed in glaucoma the vitreous changes towards the acidic side. That causes it to swell and increases IOP.

Some investigations have shown that normally the pH of the vitreous is around 7.5 to 7.6. A change in the reaction toward the acidic side causes a diminution in the volume of the vitreous until the isoelectric point, which is 4.2, is reached. The contrary has been assumed by others, that is, that the vitreous becomes more alkaline and swells.

Under normal conditions the vitreous in the living eye is at its maximum turgescence.

Choroid:

The choroid is a highly vascular membrane that can easily change its thickness by varying its blood content. Obstruction of the vortex veins occurs owing to kinking of the veins at the sinus or due to endophlebitic or sclerotic processes in the veins. Relaxation of the vasomotor mechanism causes a relaxation of the uveal vessels and an increase in the blood content of the eye.

Several local and general factors play a role in the etiology of glaucoma, including disturbances in the regulation of the intraocular vascular apparatus which cause changes in the circulation and the exchange of fluid between blood and tissues.

A close study of these theories brings the conviction that they are insufficient to explain the pathogenesis of glaucoma.

Some authors, like Thiel, hint at a disturbance in regulation, at a multiplicity of factors, and at a relation to the endocrine and sympathetic nervous systems in a vague sort of way. However, no definite theory which is based on a disturbance in regulation has so far been advanced.

ASSOCIATION OF RHEUMATOID ARTHRITIS WITH GLAUCOMA

 

Rheumatoid arthritis (RA) is a progressive, inflammatory, autoimmune disease. Several factors, including autoantibodies, immune complexes, T cell-mediated antigen-specific responses, and T cell-independent cytokine networks, are involved in the pathogenesis of RA.

There is evidence of immunological mechanisms in the development and progression of primary open-angle glaucoma (POAG). Autoantibodies and CD4+ T cells involved in the pathogenesis of RA are also observed in patients with POAG. Similarly, there is enhanced expression of Heat-Shock protein (HSP) in glaucoma patients. Another indirect evidence comes from the use of etanercept, a tumor necrosis factor–α inhibitor used to control RA progression, reduced retinal ganglion cell (RGC) loss by approximately 50% in a rat glaucoma model.

However, there is limited evidence connecting RA, the most common autoimmune disease, with the risk of developing POAG.

Kim and colleagues conducted a nationwide propensity-matched cohort study using data from the Korean National Health Insurance Service-Senior cohort from 2002 to 2013. Data analysis was performed from November 2020 to July 2021.

A total of 2049 patients with incident seropositive RA and 8196 time-dependent, propensity score–matched, risk-set controls were included.

The cumulative incidence of POAG was higher in the RA cohort than in the matched cohort during the entire follow-up period. The 2-year cumulative incidence risk of POAG was 2.36% in the RA cohort and 1.28% in the matched-control cohort; the 4-year cumulative incidence risk was 4.29% in the RA cohort and 2.64% in the matched control cohort.

POAG developed in 86 of 2049 patients with RA and 254 of 8196 matched controls.

In the RA cohort, the incidence rate of POAG was 981.8 cases per 100 000 person years (95% CI, 794.3-1213.7 cases per 100 000 person years), whereas in the matched controls, the incidence rate was 679.5 cases per 100 000 person years (95% CI, 600.8- 768.3 cases per 100 000 person years).

Patients with RA were more likely to develop POAG than the matched controls (hazard ratio [HR], 1.44; 95% CI, 1.13-1.84). Increased POAG risk in the RA cohort was predominantly observed 2 years into the follow-up period (HR, 1.83; 95% CI, 1.28-2.61) and in those aged 75 years or older (HR, 2.12; 95% CI, 1.34-3.35).

These findings suggest that RA is associated with a higher risk of developing POAG, especially within 2 years after diagnosis or among patients aged 75 years or older.

When considered collectively, it is reasonable to suspect that RA and POAG share common pathogenic pathways, including autoimmune components.

REFERENCE:

Kim SH, Jeong SH, Kim H, Park EC, Jang SY. Development of Open-Angle Glaucoma in Adults With Seropositive Rheumatoid Arthritis in Korea. JAMA Netw Open. 2022 Mar 1;5(3):e223345. doi: 10.1001/jamanetworkopen.2022.3345.

GENES ASSOCIATED WITH GLAUCOMA